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Dictionary ofAviation

second edition

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Dictionary ofAviation

second edition

David Crocker

A & C Black � London

Originally published by Peter Collin Publishingas Dictionary of Aeronautical English

First edition published 1999Second edition published 2005 by Bloomsbury Publishing Plc

Reprinted 2007 by�&C Black Publishers Ltd

38 Soho Square, London W1D 3HB

Copyright © David Crocker and Peter Collin Publishing Ltd. 1999Revisions and additional material © A&C Black Publishers Ltd 2007

All rights reserved. No part of this publication maybe reproduced in any form or by any means without the

prior written permission of the publishers.

A CIP record for this book is available from the British Library

eISBN-13: 978-1-4081-0226-8

Text Production and ProofreadingKaty McAdam, Sandra Anderson, Heather Bateman, Emma Harris

This book is produced using paper that is made from wood grown in managed,sustainable forests. It is natural, renewable and recyclable. The logging andmanufacturing processes conform to the environmental regulations of the

country of origin.

Text processed and typeset by A&C BlackPrinted in Spain by GraphyCems

PrefaceEnglish is the universal language of communication used in civil aviation. Thisdictionary provides the basic vocabulary of terms used by pilots, cabin staff,maintenance crews, ground staff and travellers worldwide. The terms are those usedin everyday work on aircraft, and cover parts of the aircraft, manipulating theaircraft on the ground and in the air, instructions to passengers, conversations withair traffic control, weather, emergencies, etc.

Unlike conventional aeronautical dictionaries, the Dictionary of Aviation definesvocabulary often found in conjunction with the purely technical terms as well as thetechnical terms themselves. Simple explanations are presented in simple language,making the dictionary ideal for those working towards a private or commercialpilot’s licence, as well as trainee maintenance engineers and more experiencedprofessionals. We also give examples to show how the words are used in context.

We have selected quotations from various specialised magazines to show the wordsand phrases as they are used in real-life situations. The supplements at the back givefurther information in the form of tables.

We are particularly grateful to the staff at Qatar Aeronautical College for their helpin the production of the first edition of this dictionary. Thanks are also due toStephen Copeland and Gavin Rowden for specialist advice and helpful suggestionsduring the preparation of this new edition.

The information contained in this dictionary is not to be regarded as a substitute forformal training in a given discipline.

Pronunciation GuideThe following symbols have been used to show the pronunciation of the mainwords in the dictionary.

Stress is indicated by a main stress mark ( � ) and a secondary stress mark ( � ) .Note that these are only guides, as the stress of the word changes according to itsposition in the sentence.

Vowels Consonants

� back b buckɑ� harm d deadɒ stop ð othera type d� jumpaυ how f fareaə hire � goldaυə hour h headɔ� course j yellowɔ annoy k cabe head l leaveeə fair m mixe make n nileυ go ŋ sing�� word p printi� keep r resti happy s saveə about ʃ shop fit t takeə near tʃ changeu annual θ theftu� pool v valueυ book w workυə tour x loch' shut � measure

z zone

AAAIB

AAIB abbreviation Air Accident Inves-tigation BranchAARA

AARA abbreviation air to air refuellingareaabbreviate

abbreviate /ə |�bri�viet/ verb toshorten a word or a text � Air TrafficControl is usually abbreviated to ATC.� abbreviated weather report a short-ened weather reportabbreviation

abbreviation /ə|�bri�vi |�eʃ(ə)n/ nounthe short form of a word or text � Aero-nautical charts use abbreviations andsymbols. � Km is the abbreviation forkilometre.

COMMENT: Abbreviations can causeconfusion. They may range from thosewhich have a very specific meaning asdefined by an authoritative body, toothers which may come aboutbecause of personal usage in note-making, etc. ICAO approvedabbreviations may differ from thoseused in JARs. AC can mean‘alternating current’ or ‘altocumulus’.CPL is generally taken to meanCommercial Pilot’s Licence but theICAO definition is Current Flight Plan.Advances in technology havesignificantly increased the number ofabbreviations with which pilots andengineers must be familiar.Abbreviations in this dictionary includethose with generally accepteddefinitions and others with specificICAO definitions.

ability

ability /ə |�blti/ noun the power,knowledge or skill needed to do some-thing � Strength is the ability of a mate-rial to support a load. � he has greatability he has good skills or is veryclever

able

able /�eb(ə)l/ adjective skilful andcompetent � to be able to to have thepower, knowledge, skill or strength todo something � Is she able to carry thisheavy suitcase?able-bodied

able-bodied /�eb(ə)l �bɒdid/ adjec-tive referring to a person who has nophysical disabilities � Physically disad-vantaged as well as able-bodied peoplecan gain a PPL.abnormal

abnormal /�b |�nɔ�m(ə)l/ adjectivenot normalabnormalityabnormality /��bnɔ� |�m�lti/ nounsomething that is not normal, expectedor correct, and is therefore possiblyworrying � Any abnormality in engineperformance should be checked.abnormal loadabnormal load /�b |�nɔ�m(ə)l �ləυd/noun a load which is heavier than nor-malabort

abort /ə|�bɔ�t/ verb 1. to stop some-thing taking place � They had to abortthe landing because of a violent storm2. to end something before it has fin-ishedabsolute

absolute /��bsəlu�t/ adjective com-plete, total � absolute necessity some-thing that you cannot manage withoutunder any circumstances � absolutesilence a condition in which no soundof any kind can be heardabsolute ceiling

absolute ceiling /��bsəlu�t �si�lŋ/noun the maximum height above sealevel at which an aircraft can maintainhorizontal flightabsolute humidity

absolute humidity /��bsəlu�t hju�|

�mdəti/ noun the vapour concentrationor mass of water in a given quantity ofair

Aviation.fm Page 1 Wednesday, November 24, 2004 3:45 PM

absolute pressure 2absolute pressure

absolute pressure /��bsəlu�t�preʃə/ noun a unit of force per unit ofarea without comparison to other pres-sure � Aircraft show absolute pressurein inches of mercury on the inlet mani-fold pressure gauge.absolute value

absolute value /��bsəlu�t �v�lju�/noun the size or value of a numberregardless of its sign � The absolutevalue of –64.32 is 64.32.absolute zero

absolute zero /��bsəlu�t �zərəυ/noun the lowest temperature possible,0 °K, or –273.15 °Cabsorb

absorb /əb |�zɔ�b/ verb to take in �

Warm air absorbs moisture more easilythan cold air. � Our bodies absorb oxy-gen. � to absorb information to under-stand and remember something � Onlya few passengers absorb the pre-depar-ture safety information.absorption

absorption /əb |�zɔ�pʃən/ noun theact of taking something in � There isabsorption of energy by the tyre whenthe aircraft lands.AC

AC abbreviation 1. alternating current2. altocumulus (ICAO)ACARS

ACARS abbreviation airborne com-munication, addressing and reportingsystemACAS

ACAS /�ek�s/ abbreviation airbornecollision avoidance systemACC

ACC abbreviation area control centreaccelerate

accelerate /ək|�seləret/ verb toincrease speed � After start-up, theengine accelerates up to idling speed. �The aircraft accelerated down the run-way and took off. Opposite decelerateacceleration

acceleration /ək |�selə|�reʃ(ə)n/noun 1. the act of increasing the speedof something or of going faster. Oppo-site deceleration (NOTE: Accelerationcan be felt as an aircraft begins its take-off run.) 2. a force that pulls outwardsand is caused by a change in directionrather than a change in speed � Acceler-ation forces can be felt during aerobaticmanoeuvres.acceleration due to earth’s gravity

acceleration due to earth’sgravity noun the pulling force exertedon a body by the Earth. It has an inter-national standard value of 9.80665

metres per second per second. Abbrevi-ation gaccelerometer

accelerometer /ək|�selə |�rɒmtə/noun an instrument that measures anaircraft’s accelerationaccept

accept /ək|�sept/ verb 1. to be able totake or receive � Some units acceptelectrical inputs from the autopilot. 2.to take or receive something when it isgiven to you � She accepted the awardon behalf of the whole crew. � to accepta gift, to accept a prize to take a prizewhich is handed to you 3. to be willingto receive or admit something � toaccept the blame to be willing to admitthat you were the person who causedsomething bad to happen � The airlineaccepted the blame for the loss of theirbaggage. � to accept responsibility tobe willing to be answerable for some-thing � The copilot accepted responsi-bility for the incident.acceptable

acceptable /ək |�septəb(ə)l/ adjectiveallowed or approved of, although it maynot be perfect � acceptable level ofsafety a good enough standard of safety� acceptable limits the limits generallyregarded as correct � there must be acontinuous flow of clean oil at anacceptable temperature the tempera-ture of the oil must be within givenmaximum and minimum figuresacceptance

acceptance /ək|�septəns/ noun 1.willingness to believe something oragree to something � There is a growingacceptance that safety is the main pri-ority. 2. willingness to do or use some-thing � acceptance of new technologywillingness to use new technologyaccepted

accepted /ək|�septd/ adjectivebelieved or recognised � It is acceptedthat incorrect use of English played apart in the accident. � It is generallyaccepted that flying is one of the safestforms of transport.access

access /��kses/ noun a way to find orget at something � to gain access to tomanage to enter a place � access toinformation the means to get at,retrieve and use information � verb tofind and use � to access data, to accessinformation to find, retrieve and usedata or information


3 according toaccessibility

accessibility /ək|�ses |�blti/ nounthe ease with which something can bereached or found � Accessibility of com-ponents and equipment during servic-ing enables work to be done morequickly.accessible

accessible /ək |�sesb(ə)l/ adjectiveeasy to get at � It is a good idea to havea set of emergency charts in an accessi-ble place in the cockpit. � Instrumentswhich need resetting in flight must beaccessible to the crew.accessoryaccessory /ək |�sesəri/ noun a systemor piece of equipment of secondaryimportance � a camera with severalaccessories � adjective of secondaryimportance � There are many accessorysystems which need engine power tooperate them – pumps, generators,magnetos, etc. (NOTE: The noun acces-sory is not connected with the nounaccess or the verb to access.)access panel

access panel /��kses �p�n(ə)l/noun a part of the aircraft skin whichcan be easily removed so internal com-ponents can be inspectedaccidentaccident /��ksd(ə)nt/ noun 1.something which happens which seemsto have no cause � it was an accidentnobody planned that it should happen ordeliberately caused it to happen � byaccident by chance � we met by acci-dent we met by chance 2. an unfortu-nate or harmful event, something caus-ing damage � An accident must bereported. � The flight attendant wasinjured in the accident.

‘Mr Skidmore lost both arms in anaccident while serving in the army as ayoung man, and is believed to be the firstpilot in the UK – and possibly the world –to go solo with two artificial arms’ [Pilot]

accidental

accidental /��ks |�dent(ə)l/ adjective1. happening by accident, not deliberateor planned � There is a safety device toprevent accidental retraction of theundercarriage. 2. relating to an acci-dent, or happening as a result of an acci-dent � We were told of his accidentaldeath.accompanied

accompanied /ə|�k�mp(ə)nid/adjective found together with � accom-panied luggage luggage which belongs

to one of the passengers and is carriedon the same aircraft. � unaccompaniedaccompany

accompany /ə |�k�mp(ə)ni/ verb togo together with something else �

Engine failure is sometimes accompa-nied by fire. � Mr Smith was accompa-nied by his wife and children on theflight to New York Mr Smith’s wifeand children were with him on the flightaccomplish

accomplish /ə |�k�mplʃ/ verb (in for-mal technical texts) to do something �

Feathering is accomplished by movingthe pilot’s control lever. � Retraction ofthe undercarriage is accomplished byelectrical power. � to accomplish atask to successfully finish doing some-thing demanding � She was the firstwoman to accomplish the feat in a sin-gle-engined aircraft.accomplishment

accomplishment /ə |�k�mplʃmənt/noun 1. an achievement � Charles Lind-bergh’s flight across the Atlantic in May1927 was a great accomplishment. 2.(in physics) work done � Power is meas-ured by units of accomplishment corre-lated with time.accordance

accordance /ə |�kɔ�d(ə)ns/ noun � inaccordance with in agreement with orfollowing something such as rules,instructions or laws � Fuels must beused in accordance with instructions. �in accordance with Buys Ballot’s Lawas described by Buys Ballot’s Law

‘…use full heat whenever carburettorheat is applied, partial hot air should onlybe used if an intake temperature gauge isfitted and only then in accordance withthe Flight Manual or Pilot’s OperatingHandbook’ [Civil Aviation Authority,General Aviation Safety Sense Leaflet]

accordingly

accordingly /ə |�kɔ�dŋli/ adverb asneeded � Check for increasing manifoldpressure and reduce power accordingly.according to

according to /ə |�kɔ�dŋ tu�/ preposi-tion 1. as determined by or in relation to� The force exerted by the pilot on thecontrol column will vary according to anumber of factors. 2. as written or saidby somebody else � According to thecopilot, engine vibration was detectedin engine number one. 3. in agreementwith something, e.g. instructions, etc. �according to instructions exactly as


account 4

said in the instructions � according torequirements as requiredaccountaccount /ə |�kaυnt/ noun � to takesomething into account to remembersomething and consider it carefully �

When planning a flight, wind speed anddirection must be taken into account. �

In the event of an in-flight emergency,the aircraft should be landed at thenearest suitably equipped airport, tak-ing into account fuel available. � on noaccount under no circumstances, never� On no account should anybody fly anaircraft without carrying out pre-flightchecks.account foraccount for /ə |�kaυnt fə/ verb 1. tomake up or constitute � Kevlar and car-bon fibre account for a large percentageof the materials used in modern air-craft. 2. to provide the main reason forsomething � High humidity accountedfor the longer take-off run.accreteaccrete /ə|�kri�t/ verb to increase inamount by slow external addition, toaccumulate � ice accretes on the rotorice builds up on the rotoraccretionaccretion /ə |�kri�ʃ(ə)n/ noun increaseor accumulation by slow external addi-tion � Ice accretion can cause loss of liftand significantly increase the weight ofthe aircraft.accumulateaccumulate /ə |�kju�mjυlet/ verb tocollect and increase � Due to katabaticeffects, cold air flows downwards andaccumulates over low ground.accumulationaccumulation /ə|�kju�mjυ|�leʃ(ə)n/noun the collection and increase ofsomething � Fire in a toilet couldpresent difficulties due to the confinedspace and possible smoke accumula-tion.accumulatoraccumulator /ə |�kju�mjυletə/ noun1. a device for storing energy in hydrau-lic systems � An accumulator is fitted tostore hydraulic fluid. 2. an electric cir-cuit in a calculator or computer, inwhich the results of arithmetical andlogical operations are formedaccuracyaccuracy /��kjυrəsi/ noun 1. thestate of being correct � to check foraccuracy to make certain that the resultis correct 2. the ability to find, hit orshow things correctly � The accuracy of

modern navigational equipment ismuch greater than older systems.accurateaccurate /��kjυrət/ adjective 1. cor-rect � Skill in accurate flying can onlybe achieved by practice. � accurateresults results which are exactly correct2. precise � This watch is very accurate.ACFTACFT abbreviation aircraftachieve

achieve /ə |�tʃi�v/ verb 1. to manage todo something demanding � In order toachieve a safe landing in a crosswind,the correct techniques must be used. 2.to obtain � In wind shear conditions, afly-by-wire system allows the pilot toachieve maximum lift by pulling hardback on the stick without risk of a stall.achievementachievement /ə |�tʃi�vmənt/ nounsomething difficult that somebody suc-ceeds in doing and feels proud about �

For most trainee pilots, making theirfirst solo flight is a great achievement.acid

acid /��sd/ noun a chemical sub-stance which reacts with a base to forma salt � sulphuric acid (H2SO4) (NOTE:An acid turns a litmus indicator red andhas a sour taste.)acidity

acidity /ə |�sdti/ noun having an acidcontent � the acidity of a substance theamount of acid in a substanceacid-proofacid-proof /��sd pru�f/ adjectiveable to resist the harmful effects of anacidacid testacid test /��sd �test/ noun a difficultor exacting test of worth or quality � Apilot’s ability to react appropriately inan emergency situation is the acid testof his or her professionalism.ACMSACMS noun a computer which recordsinformation from various aircraft sys-tems during flight. Full form aircraftcondition monitoring systemACNACN abbreviation aircraft classifica-tion numberacousticacoustic /ə |�ku�stk/ adjective refer-ring to soundacoustic ear muffs

acoustic ear muffs /ə |�ku�stk �ə�m�fs/ plural noun coverings to protectthe ears from loud noise. Also calledear protectors, ear defendersacquire

acquire /ə |�kwaə/ verb to buy or oth-erwise obtain � to acquire a new air-


5 adapt

craft � Speed control is used to acquireand maintain a selected airspeed.acquisitionacquisition /��kw|�zʃ(ə)n/ nounthe act of buying or otherwise obtaining� Each computer checks data acquisi-tion. � The image of the airlineimproved after the acquisition of thenew aircraft.acronymacronym /��krənm/ noun a wordwhich is made up of the initial letters ofa name, and is pronounced as a word �

NASA is the acronym for National Aer-onautics and Space Administration. �

VASI is the acronym for visualapproach slope indicator.actact /�kt/ verb 1. to behave in a partic-ular way � The crew must act withauthority. 2. to take the role of � Moun-tain ranges act as a barrier. � The gov-ernor spill valve also acts as a safetyrelief valve. 3. � to act on to produce aneffect � Bending and twisting forces acton a propeller. � Gravity acts verticallydownwards.actingacting /��ktŋ/ adjective temporarilytaking on the responsibilities of some-body � Captain Smith will be actingChief Flying Instructor while CaptainWhite is absent from work.actionaction /��kʃən/ noun 1. somethingdone or to be done � to take action toso something � If there is a risk of colli-sion, the crew should take the appropri-ate action. 2. an effectactivateactivate /��ktvet/ verb to make asystem or a piece of equipment or a pro-cedure start to work or to operate � Thesystem is activated by the pilot or copi-lot. � The sounding of the alarm willactivate emergency procedures.activationactivation /�kt|�veʃ(ə)n/ noun theact of making something start to workor to operate � Activation may bemechanical or electrical.activeactive /��ktv/ adjective 1. live, inaction or use � the system is active thesystem is on and working 2. not passive� in a secondary radar system, thetarget is active in a secondary radarsystem the target transmits a signalwhile in a primary radar system it doesnot 3. � active Cb clouds developingcumulonimbus clouds

active runwayactive runway /��ktv �r�nwe/noun a runway that is being used

‘…never cross an active runway withoutpermission from the tower: there may bemore than one active runway’ [CivilAviation Authority, General AviationSafety Sense Leaflet]

activityactivity /�k |�tvti/ noun a movementor action of some kind � Sunspot activ-ity can affect the amount of solar radia-tion.actualactual /��ktʃuəl/ adjective real � Theactual path of the aircraft over theground is called its track, which maynot be the same as the desired course.actuallyactually /��ktʃuəli/ adverb in fact, inreality � The design is such that,although the aircraft loses altitude rap-idly, it does not actually stall.actuateactuate /��ktʃu |�et/ verb 1. to move adevice or a part � The fore and aft move-ment of the control column actuates theelevators. 2. to switch on a system or apiece of equipment, or put it into opera-tion � A lever actuates the fire delugesystem. 3. to put a procedure into action� Receipt of the distress signal willactuate the support facilities at the air-port.actuationactuation /�ktʃυ |�eʃ(ə)n/ noun 1.the act of making a device or a partmove � electrical actuation the use ofan electric motor to make somethingmove � mechanical actuation the useof a mechanical part such as a rod, armor lever to make something move 2. amovement made by a device or partactuatoractuator /��ktʃυetə/ noun a devicewhich changes electrical or hydraulicenergy into mechanical motion � Theactuator control is sensitive to enginerpm. � Actuators are classified as eitherlinear or rotary.AD

AD abbreviation airworthiness direc-tiveA/D

A/D abbreviation aerodromeADAADA abbreviation advisory airspaceadaptadapt /ə |�d�pt/ verb 1. to change ormodify for special use � The turbopropengine is often used in transport air-craft and can be adapted for use in sin-gle-engine aircraft. 2. to change to suit


adaptation 6

new conditions � Crew flying long-haulroutes have to adapt to time changes.adaptationadaptation /��d�p |�teʃ(ə)n/ noun 1.the act of changing or modifying some-thing for special use � Doppler VOR isan adaptation of VOR to reduce errorscaused by location. 2. adjustment tonew conditions � Adaptation to timechanges when travelling west to easttakes time.adapteradapter /ə |�d�ptə/ noun 1. a piece ofequipment or device which allows achange or modification � a ‘T’ pieceadapter a device for connecting twoinputs to one output or vice versa 2. adevice that allows two incompatibledevices to be connectedADCADC /�e di� �si�/ abbreviation air datacomputeraddadd /�d/ verb 1. to put figures togetherto form a sum, to make a total � Add thetwo numbers together to find the sum. 2.to put together to make a larger group ora group with different properties �

There are only nine chairs, add anotherone. � A substance is added to the fuelto clean fuel injectors.additionaddition /ə |�dʃ(ə)n/ noun 1. a mathe-matical operation consisting in puttingnumbers together � Addition is nor-mally taught before subtraction, multi-plication and division. � The additionsign is +. 2. the act of adding something� With the addition of methanol, the tur-bine inlet temperature is restored. 3. �in addition also � in addition to aswell asadditionaladditional /ə |�dʃ(ə)nəl/ adjectiveadded or extraadditiveadditive /��dtv/ noun a chemicalsubstance, often liquid, added toanother substance to give it extra quali-ties � Additives are used in engine oilsto prolong the life of the engine. � Anti-icing additives are used in radiatorcoolants.adequateadequate /��dkwət/ adjectiveenough, sufficient � The compressormust provide an adequate airflowthrough the engine. � adequate fuelenough fuelADFADF abbreviation automatic directionfinder

adhereadhere /əd |�hə/ verb to stick as ifglued � Clear ice adheres strongly toairframes.adhesiveadhesive /əd|�hi�sv/ noun glue �

adjective having the sticking quality ofglue � adhesive tape � Adhesive bond-ing of aluminium parts is widelyemployed.ADIADI /edi� |�a/ abbreviation attitudedirection indicator or attitude directorindicatoradiabaticadiabatic /��də|�b�tk/ adjective 1.referring to processes through whichheat cannot be lost or gained 2. refer-ring to a change in temperature in amass of air, which occurs when the airis compressed or expanded by anincrease or decrease in atmosphericpressure and does not involve the airlosing heat to, or gaining heat from, itssurroundingsadiabatic compressionadiabatic compression/��dəb�tk kəm|�preʃ(ə)n/ nouncompression caused by atmosphericfactors, which makes descending airwarm upadiabatic coolingadiabatic cooling /��dəb�tk�ku�lŋ/ noun a process in whichascending air is cooled by a decrease inatmospheric pressure without heattransferadiabatic expansionadiabatic expansion /��dəb�tkk |�sp�nʃ(ə)n/ noun expansion causedby atmospheric factors, which makesascending air cool down � Cooling byadiabatic expansion may result in cloudformation.adiabatic heatingadiabatic heating /�diə |�b�tk�hi�tŋ/ noun a process in whichdescending air is heated by an increasein atmospheric pressure without heattransferadjacentadjacent /ə|�d"es(ə)nt/ adjectivenext to or near � Fire extinguishersshould be positioned adjacent to theaircraft during all ground-runningoperations.adjustadjust /ə |�d"�st/ verb to change andimprove the position or setting of apiece of equipment � The pilot adjuststhe throttle or propeller controls. � toadjust the seat to move the seat into aposition suitable for yourself � to


7 advice

adjust the volume to increase ordecrease the volume to improve thesound qualityadjustableadjustable /ə|�d"�stəb(ə)l/ adjectivedesigned to be adjusted � An adjustablestop on the throttle control ensures apositive idling speed.adjustmentadjustment /ə |�d"�stmənt/ noun 1. achange to improve the setting, positionor operation of something � A slightadjustment to the seat will make it muchmore comfortable to sit in. 2. the act ofchanging something to improve its set-ting or position � Maximum systempressure is often controlled by adjust-ment of the main engine-driven pump.admitadmit /əd |�mt/ verb to allow to enter �Cold air can be admitted to the cabinthrough adjustable louvres or shutters.adoptadopt /ə |�dɒpt/ verb to choose to usesomething as standard equipment or tomake it standard procedure � A policy ofno smoking on all flights has beenadopted by many airlines. � widelyadopted now in standard use with manycompanies, institutions and organisa-tionsadoptionadoption /ə |�dɒpʃən/ noun the act ofusing something as standard equipmentor making it standard procedure � Inspite of the adoption of the axial flowtype compressor, some engines retainthe centrifugal type.ADRADR abbreviation accident datarecorderADSADS abbreviation automatic depend-ent surveillanceADTADT abbreviation approved departuretimeadvanceadvance /əd|�vɑ�ns/ noun 1. a changethat improves something � enormousadvances in aircraft design greatprogress or developments in aircraftdesign 2. � in advance of ahead of �

The Gulf region is three hours inadvance of GMT. � verb 1. to move for-wards, or move something forwards �the throttle lever is advanced thethrottle lever is moved forwards 2. tomake something happen at an earliertime � to advance the ignition to adjustthe timing of the ignition so that thespark occurs earlier

advancedadvanced /əd |�vɑ�nst/ adjectivemodern and sophisticated � The A340 isan advanced type of aircraft.

‘…a Seattle-based modification companyspecializing in advanced winglet designsis developing a lightweight winglet forthe Boeing 747 200F’ [FlightInternational 1–7 May 1996]

advantageadvantage /əd |�vɑ�ntd"/ noun agood or beneficial factor � The multi-wheel combination has the advantageof smaller and lighter undercarriagestructures. � to take advantage of toget benefit from a situation � to takeadvantage of favourable winds to usetailwinds to increase ground speed andthus save time and money. Oppositedisadvantageadvantageousadvantageous /��dvən |�ted"əs/adjective better � the most advanta-geous the best � The minimum time pathis the most advantageous for economy.advectadvect /əd|�vekt/ verb to move in ahorizontal direction due to convection �Dispersal of hill fog takes place whensurface heating lifts the cloud base ordrier air is advected.advectionadvection /əd |�vekʃ(ə)n/ noun themovement of air in a horizontal direc-tionadvection fogadvection fog /əd |�vekʃ(ə)n fɒ$/noun fog which forms when warmermoist air moves over a colder surfaceadventadvent /��dvent/ noun an arrival,especially of something very important� With the advent of satellite navigationsystems, pilots of light aircraft have amore accurate means of knowing theirposition.adverseadverse /��dv%�s/ adjective 1. bad orpoor � Only in extremely adverse condi-tions should the crew evacuate the air-craft. � adverse handling characteris-tics aspects of an aircraft’s handlingwhich are poor 2. acting or goingagainst youadverse yawadverse yaw /��dv%�s jɔ�/ noun yawcaused by aileron drag, in the oppositedirection to the direction of the intendedturnadviceadvice /əd|�vas/ noun useful or help-ful information � The instructor’sadvice was of great help to the student


advisability 8

pilot. (NOTE: Advice has no pluralform.)advisability

advisability /əd |�vazə |�blti/ noun �the advisability of something whethersomething is a good idea or not � Flyingmanuals often contain guidance on theadvisability of flying with a cold.advisable

advisable /əd|�vazəb(ə)l/ adjectiverecommended, suggested � It is advisa-ble to check the condition of the tyresafter each landing.advise

advise /əd |�vaz/ verb 1. to inform, tonotify � The flight deck advised thecabin crew that descent would start in20 minutes. 2. to recommend, to sug-gest � Because of the bad weather, theinstructor advised the trainee pilot notto fly. � to advise against to recom-mend or to suggest that somethingshould not be doneadvisory

advisory /əd |�vaz(ə)ri/ adjective giv-ing advice and informationadvisory airspace

advisory airspace /əd |�vaz(ə)ri�eəspes/ noun airspace containingadvisory routes in which air traffic con-trol provide an advisory service but notfull control. Abbreviation ADAadvisory route

advisory route /əd |�vaz(ə)ri ru�t/noun a published route for which thereis an advisory service. AbbreviationADRadvisory service

advisory service /əd |�vaz(ə)ri�s%�vs/ noun a service in which AirTraffic Control provides advice andinformation to assist a pilot in the safeconduct of a flightAEEC

AEEC abbreviation airlines electronicengineering committeeaerate

aerate /�eəret/ verb to put a gas,especially carbon dioxide or air, into aliquid so that bubbles are formed � Aer-ated fuel causes problems. Opposite de-aerateaeration

aeration /eə |�reʃ(ə)n/ noun the act ofputting a gas, especially carbon dioxideor air, into a liquid � The purpose of thebooster pump is to prevent fuel aera-tion. Opposite de-aerationaerator

aerator /eə |�retə/ noun a device to puta gas – especially carbon dioxide or air– into a liquid. Opposite de-aerator

aerialaerial /�eəriəl/ adjective 1. happeningin the air 2. done by an aircraft in flight� noun a device to send or receive radioor TV signals � Ice-covering reducesthe effectiveness of aerials. (NOTE: TheUS English word with this meaning isantenna.)aerial displayaerial display /�eəriəl ds|�ple/ nouna display of flying skills and aircraftperformanceaerial photographyaerial photography /�eəriəl fə |

�tɒ$rəfi/ noun photography done froman aircraft in the airaero-aero- /eərəυ/ prefix 1. referring to theair � aerodynamic 2. referring to air-craft � aero-engine � aero-towaerobaticaerobatic /�eərə|�b�tk/ adjectivereferring to aerobatics � Loops and rollsare aerobatic manoeuvres.aerobatic aircraftaerobatic aircraft /�eərəb�tk�eəkrɑ�ft/ noun an aircraft which isdesigned to perform aerobatics

COMMENT: One of the most famouscompetition aerobatic aircraft is thePitts Special which first flew in 1944.

aerobatic displayaerobatic display /�eərəb�tk ds |

�ple/ noun a demonstration, often pub-lic, of piloting skill and aircraft per-formanceaerobaticsaerobatics /�eərəυ |�b�tks/ noun theart of performing spectacular controlledmovements in a flying aircraft for thepurposes of entertainment or competi-tion � The Russian pilot gave a greatdisplay of aerobatics.aerobatic teamaerobatic team /�eərə |�b�tk �ti�m/noun a team of pilots and aircraft whoperform aerobaticsaerodromeaerodrome /�eərədrəυm/ noun anyarea of land or water designed for thetaking off and landing of aircraft � Air-ports and military air bases or stationsare types of aerodrome. � All aero-dromes are marked on charts. Abbrevi-ation A/D � disused aerodrome an aer-odrome which is no longer in use for thepurpose of taking off and landing aero-planesaerodrome boundariesaerodrome boundaries/�eərədrəυm �baυnd(ə)riz/ plural nounthe physical or geographical limits of anaerodrome


9 aeronauticsaerodrome circuitaerodrome circuit /�eərədrəυm�s%�kt/ noun the pattern and directionof aircraft movement in the air aroundthe aerodromeaerodrome QFEaerodrome QFE /�eərədrəυm �kju�ef �i�/ noun the barometric pressure set-ting at which the altimeter reads zerowhen the aircraft is on the runwayaerodrome QNHaerodrome QNH /�eərədrəυm �kju�en �etʃ/ noun the barometric pressuresetting at which the altimeter reads aer-odrome elevation when the aircraft is onthe runwayaerodrome surveillance monitoring indicatoraerodrome surveillance moni-toring indicator /�eərədrəυm�s%�veləns �mɒntərŋ �ndketə/noun same as airport surface detec-tion equipmentaerodrome traffic zoneaerodrome traffic zone/�eərədrəυm �tr�fk �zəυn/ noun anarea of protected airspace around anaerodrome, which pilots need permis-sion to enter or to move in. Abbrevia-tion ATZaerodynamicaerodynamic /�eərəυda|�n�mk/adjective 1. referring to the way inwhich objects are affected when theymove through the atmosphere 2. refer-ring to a smooth rounded shape whichmoves easily through the air � aerody-namic design a streamlined shape thatenables something to move easilythrough the airaerodynamic brakingaerodynamic braking /�eərəυdan�mk �brekŋ/ noun the brakingeffect of dragaerodynamic forcesaerodynamic forces /�eərəυdan�mk �fɔ�sz/ noun the forces ofthe air which act on an aircraft in flightaerodynamic resistanceaerodynamic resistance /�eərəυdan�mk r |�zstəns/ noun same asdragaerodynamicsaerodynamics /�eərəυda |�n�mks/noun the science that deals with theinteraction of moving objects with theatmosphere � Aerodynamics is one ofthe major areas of study for a traineepilot.aerodyneaerodyne /�eərəυdan/ noun an air-craft that is heavier than air and whoselift in flight results from forces causedby its motion through the air, e.g. aplane or helicopter

aero-engineaero-engine /�eərəυ �end"n/ nounan engine used in aircraft � Most pistonaero-engines are cooled by air.aerofoilaerofoil /�eərəυfɔl/ noun a surfacewhich is shaped to produce more liftthan drag when moved through the air �Wings, ailerons, elevators, fins and pro-pellers are all examples of aerofoils.(NOTE: The US English word is airfoil.)aeronauticalaeronautical /�eərə|�nɔ�tk(ə)l/adjective referring to aeronauticsaeronautical chartaeronautical chart /�eərə|

�nɔ�tk(ə)l �tʃɑ�t/ noun a map used inair navigation which may include topo-graphic features, hazards and obstruc-tions, navigational aids and routes, des-ignated airspace and airportsaeronautical engineeraeronautical engineer/�eərənɔ�tk(ə)l �end"|�nə/ noun anengineer who specialises in the designof aircraftaeronautical engineeringaeronautical engineering/�eərəυnɔ�tk(ə)l �end" |�nərŋ/ nounthe science or study of the design of air-craftaeronautical fixed serviceaeronautical fixed service/�eərənɔ�tk(ə)l �fkst �s%�vs/ noun aradio communications service betweenfixed points that is designed to enableaircraft to travel safely. AbbreviationAFSaeronautical fixed telecommunication networkaeronautical fixed telecommu-nication network /�eərənɔ�tk(ə)l�fkst �telikəmju�n|�keʃ(ə)n �netw%�k/noun a ground-based network of tele-printers that transmits flight plans andsimilar data between control centres.Abbreviation AFTNaeronautical information circularaeronautical information circu-lar /�eərənɔ�tk(ə)l �nfə|�meʃ(ə)n�s%�kjυlə/ noun a notice issued by anaviation authority in which informationis given about administrative, technical,safety or operational mattersAeronautical Information PublicationAeronautical Information Publi-cation noun a document issued by astate in which information is givenabout aviation in that country. Abbrevi-ation AIPaeronauticsaeronautics /�eərə |�nɔ�tks/ noun 1.the science of aircraft design, construc-tion and operation 2. the theory andpractice of aircraft navigation


aeroneurosis 10aeroneurosis

aeroneurosis /�eərəυnjυ |�rəυss/noun anxiety and fatigue in airlinepilots as a result of long periods of fly-ingaeroplane

aeroplane /�eərəplen/ noun apower-driven, heavier-than-air craftwith fixed wings (NOTE: Many peopleuse the words aeroplane and aircraftas if they had exactly the same mean-ing. However, aeroplanes, hot-air bal-loons, helicopters, airships and glidersare all aircraft. The US English is air-plane.)aeroplane performance

aeroplane performance/�eərəplen pə|�fɔ�məns/ noun adescription in figures of what a planecan do, including, e.g., its speed, rate ofclimb, and the length of its take-off runaerostat

aerostat /�eərəυst�t/ noun a hot-airor gas-filled aircraft, e.g. an airship orballoonaero-tow

aero-tow /�eərə |�təυ/ noun a tech-nique of using a powered aircraft to pulla glider into the air � An aero-tow to2,000 feet costs $25.AFCS

AFCS abbreviation automatic flightcontrol systemAFDS

AFDS abbreviation autopilot flightdirector systemaffect

affect /ə|�fekt/ verb to have an influ-ence on something, or cause a change insomething � Humidity and air densityare factors which affect the output of theengine. Compare effectAFI

AFI abbreviation assistant flyinginstructorAFIC

AFIC abbreviation assistant flyinginstructor courseAFIS

AFIS abbreviation aerodrome flightinformation serviceAFS

AFS abbreviation aeronautical fixedserviceaft

aft /ɑ�ft/ adjective towards the rear partof the aircraft � The rear part of thefuselage is called the aft section. � aftcabin the passenger compartment at theback of the aircraft � adverb rearwardsor backwards � to move the controlcolumn aft to move the control columnbackwards. Opposite fore, forward

afterafter /�ɑ�ftə/ adjective positionedcloser to the rear of an aircraft � adverbcloser to the rear of an aircraftafterburnerafterburner /�ɑ�ftəb%�nə/ noun asystem that injects fuel into the hotexhaust gases of a jet engine in order toincrease thrustAFTNAFTN abbreviation aeronautical fixedtelecommunication networkagentagent /�ed"ənt/ noun 1. a chemicalsubstance which causes a change � Ifde-icing fluid is used as an anti-icingagent it should be sprayed onto the air-craft before the onset of icing. � extin-guishing agent a substance used to putout fires 2. a person who represents acompany or arranges something for acompany � the agent for British Air-ways � a travel agentaggregateaggregate /��$r$ət/ noun the totalobtained by adding � The aggregate ofthe capacity of all the fuel tanks is 50gallons. � verb to add or come togetherto form a mass or total � Ice crystalsaggregate to form snowflakes.AGLAGL abbreviation above ground levelagreeagree /ə |�$ri�/ verb 1. to have the sameidea or opinion about something � Thecrew agreed with the findings of theinvestigation. 2. to come to an under-standing � After hours of discussion, thecabin staff agreed to call off the plannedstrike.agreedagreed /ə |�$ri�d/ adjective generallyaccepted � The millibar is an agreedunit of pressure.agreementagreement /ə |�$ri�mənt/ noun 1. thestate of having the same idea or opinionas somebody � we are in agreement weagree 2. a document in which the thingsthat two or more people or organisa-tions have agreed to do are writtendown � Regional Air Navigation Agree-mentsaheadahead /ə|�hed/ adverb in front � lookahead look some distance in front ofyou � straight ahead directly in frontahead ofahead of /ə |�hed əv/ preposition 1. infront of � Air ahead of a cold front iswarmer than air behind a cold front. 2.in advance of or at an earlier time than� The flight from Paris arrived 10 min-utes ahead of schedule.


11 aircraftAHRSAHRS noun a sensor which providesinformation on the pitch, bank andheading of an aircraft. Full form atti-tude heading reference systemAIAI abbreviation attitude indicatorAIAAAIAA abbreviation area of intense airactivityAICAIC abbreviation aeronautical informa-tion circularaidaid /ed/ noun something which helpssomebody do something � verb to help� Computers can aid students in theirstudies.AIDSAIDS /edz/ abbreviation 1. airborneintegrated data system 2. aircraft inte-grated data systemaileronaileron /�elərɒn/ noun a horizontalcontrol surface hinged to the main-plane, which enables an aeroplane tobank or roll � By rotating the yoke theailerons are moved and the aircraft rollsinto a turn. (NOTE: The word comesfrom the French ‘aile’, meaning ‘wing’.)aimaim /em/ noun a goal or objective � A100% safe operation is the aim of allairline companies. � verb to intend or totry to do something � we aim to suc-ceed we intend to succeedAIPAIP abbreviation Aeronautical Infor-mation Publicationairair /eə/ noun the mixture of gaseswhich forms the Earth’s atmosphere �

Air enters the cabin through an inlet.AIRACAIRAC abbreviation aeronauticalinformation regulation and controlAir Accident Investigation BranchAir Accident InvestigationBranch /�eər ��ksd(ə)nt n |�vest |

�$eʃ(ə)n �brɑ�ntʃ/ noun the depart-ment of the CAA of the United King-dom responsible for establishing thecause of accidents. Abbreviation AAIBairborneairborne /�eəbɔ�n/ adjective liftedand kept in the air by aerodynamicforces � Shortly after the aircraftbecomes airborne, the undercarriage isretracted.airborne installationairborne installation /�eəbɔ�n�nstə |�leʃ(ə)n/ noun a radio device inan aircraft which operates in conjunc-tion with a ground installation � Theairborne installation comprises anantenna, receiver and indicator(s).

airborne weather radarairborne weather radar /�eəbɔ�n�weθə �redɑ�/ noun a radar installationin an aircraft to give the flight crewinformation about the weather alongtheir route. Abbreviation AWRair-breathing engineair-breathing engine /�eə �bri�θŋ�end"n/ an engine that burns a mixtureof liquid fuel and air (NOTE: There arefour types of air-breathing engine: turbojet, turbo prop, turbofan and ramjet.)air bridgeair bridge /�eə brd"/ noun a link pro-vided by aircraft that carry people andsupplies between two places, especiallyin situations where travel by land is notpossibleAirbusAirbus /�eəb�s/ a trademark for alarge passenger jet aircraft manufac-tured by aerospace companies from dif-ferent European countries workingtogetherair conditionerair conditioner /�eə kən |�dʃ(ə)nə/noun a device which filters and coolsthe air in a room or in an aircraft � Inorder to obtain maximum engine power,the air conditioner should be switchedoff for take-off.air conditioningair conditioning /eə kən |�dʃ(ə)nŋ/noun a system for controlling the tem-perature of the air in a building or in anaircraftair-cooledair-cooled /�eə �ku�ld/ adjectivecooled by means of a flow of air � air-cooled engines piston aero-enginescooled by air, not waterair corridorair corridor /�eə �kɒrdɔ�/ noun aroute that aircraft must take through anarea in which flying is restrictedaircraftaircraft /�eəkrɑ�ft/ noun a machinethat is able to travel through the air �

Aeroplanes, gliders, balloons, airships,helicopters, etc., are all aircraft. Abbre-viation ACFT (NOTE: Aircraft has noplural form.)aircraft classification numberaircraft classification number/�eəkrɑ�ft �kl�sf|�keʃ(ə)n �n�mbə/noun a number expressing the relativeeffect of an aircraft on a pavement for aspecified sub-grade strength. Abbrevia-tion CANaircraftaircraft condition monitoringsystem /�eəkrɑ�ft kən |�dʃ(ə)n�mɒnt(ə)rŋ �sstəm/ noun full formof ACMS


aircraft configuration 12aircraft configurationaircraft configuration /�eəkrɑ�ftkən |�f$ə |�reʃ(ə)n/ noun a particularcombination of moveable parts such asflaps and landing gear that affects theaerodynamics of the aircraftaircraft proximity hazardaircraft proximity hazard/�eəkrɑ�ft prɒk |�smti �h�zəd/ nounsame as airproxaircraft stabilityaircraft stability /�eəkrɑ�ft stə |

�bləti/ noun the tendency of an aircraftto return to its original attitude afterbeing deflectedaircrewaircrew /�eəkru�/ noun the pilot, nav-igator and other crew members of anaircraftair cushion vehicleair cushion vehicle /�eə �kυʃ(ə)n�vi�k(ə)l/ noun same as hovercraftair data computerair data computer /�eə �detə kəm |

�pju�tə/ noun an electronic devicewhich provides information such as airtemperature, airspeed and static pres-sure. Abbreviation ADCair densityair density /�eə �densəti/ noun thedensity of the atmosphereairfieldairfield /�eəfi�ld/ noun an area of landgiven over to runways, taxiways andaprons � When the pressure setting onthe altimeter is set to 1013.25 millibars,the pressure altitude of the airfield isknown as QNE.air filterair filter /�eə �fltə/ noun a device tofilter solid particles out of the air inengine and ventilation systemsairflowairflow /�eəfləυ/ noun 1. the move-ment of air over the aircraft as it travelsthrough the atmosphere 2. a current ofair flowing through or past an object orbody � The compressor must provide anadequate airflow through the engine.airfoilairfoil /�eərfɔl/ noun US same asaerofoilairframeairframe /�eəfrem/ noun the body ofthe aircraft without the engines, instru-ments and internal fittings � The air-frame has to be built to very specificrequirements.airframe icingairframe icing /�eəfrem �asŋ/noun ice that forms on the aircraft struc-ture as opposed to on components suchas carburettorsair gapair gap /�eə $�p/ noun a spacebetween two things � air gap type

spark plug a spark plug with a spacebetween the electrodes, across whichthe spark jumpsair intakeair intake /�eə �ntek/ noun the frontpart of a jet engine where air entersair laneair lane /�eə len/ noun a regular routethat aeroplanes fly alongairlineairline /�eəlan/ noun a companywhich manages air transport servicesfor passengers or goods � Which airlineis she working for, Air France or AirCanada? � Most airlines do not allowpassengers to smoke during flight.airlinerairliner /�eəlanə/ noun an aeroplanedesigned to carry large numbers of pas-sengers � Concorde is the world’s fast-est airliner.airline representativeairline representative /�eəlan�repr |�zentətv/ noun a person whoacts on behalf of an airline, or a personwho works for an airline � Passengersshould assemble in the departurelounge where an airline representativewill meet them.airline security areaairline security area /�eəlan s |

�kjυərti �eəriə/ noun an area in whichmeasures are taken by an airline toensure the safety of people and propertyAirline Transport Pilot’s LicenceAirline Transport Pilot’sLicence /�eəlan �tr�nspɔ�t �paləts�las(ə)ns/ noun the licence that a per-son must have to be the pilot-in-com-mand or co-pilot of a public transportaircraft. Abbreviation ATPLairmanairman /�eəmən/ noun a person whois a member of a country’s Air Forceairmanshipairmanship /�eəmənʃp/ noun all-round skill in piloting an aircraft whichincludes academic knowledge, com-mon sense, quick reactions, awareness,experience, consideration for other peo-ple and property � Keeping a carefullookout for other aircraft in the circuitis good airmanship.

‘I was always told by my airmanshipinstructor, in an emergency, to find thelargest piece of asphalt with the biggestfire trucks’ [INTER PILOT]

air massair mass /�eə m�s/ noun a very largemass of air in the atmosphere in whichthe temperature is almost constant andwhich is divided from another mass bya front � Air masses are divided into two


13 air taxi

types according to source region, andthese are known as polar and tropicalair masses.airparkairpark /�eəpɑ�k/ noun a small air-port, usually found near a business orindustrial centreairplaneairplane /�eəplen/ US same as aero-planeair pocketair pocket /�eəpɒkt/ noun a smallarea where the air is less dense or wherethere is a downward air current, andwhich makes an aircraft lose heightsuddenlyair pollutionair pollution /eə pə|�lu�ʃ(ə)n/ nounpollution of the air by gas, smoke, ash,etc. � Solid particles in the air includedust, sand, volcanic ash and atmos-pheric pollution. Also called atmos-pheric pollutionairportairport /�eəpɔ�t/ noun a civil aero-drome designed for the take-off andlanding of passenger-carrying aircraftfor the general public and/or cargo air-craft � London Heathrow is one of thebusiest airports in the world. Abbrevia-tion A/Pairport authorityairport authority /�eəpɔ�t ɔ�|�θɒrti/noun the organisation responsible forthe running of an airportairport security officerairport security officer /�eəpɔ�t s |

�kjυərti �ɒfsə/ noun a personemployed by an airport authority tocheck passengers and baggage for ille-gal substances or devices, e.g. drugs,gunsairport surface detection equipmentairport surface detection equip-ment /�eəpɔ�t �s%�fs d |�tekʃ(ə)n |

�kwpmənt/ noun short-range radarequipment that scans the surface area ofan airport and tracks the movement ofaircraft and other vehicles on thegroundairproxairprox /�eəprɒks/ noun a situation inwhich aircraft are too close to oneanother in an area of airspace and thereis the possibility of danger to them.Also called aircraft proximity hazardair-sea rescueair-sea rescue /�eə si� �reskju�/noun a rescue at sea in which aircraft,especially helicopters, are usedairshipairship /�eəʃp/ noun a powered, gas-filled balloon which can be steered � An

airship is classified as a lighter-than-air craft.airshowairshow /�eəʃəυ/ noun a public dis-play of aircraft in flight and on theground, held at an airfieldairsideairside /�eəsad/ noun the part of anairport where the aircraft take off andland, load, or unloadair sockair sock /�eə sɒk/ noun same as wind-sockairspaceairspace /�eəspes/ noun the part ofthe atmosphere that is above a particulargeographical area and is subject to thelaws of a particular country or control-ling authority � The Korean 747 flewinto Soviet airspace and was shot down.airspeedairspeed /�eəspi�d/ noun the speed ofthe aircraft relative to the air around it �Maintain a constant airspeed on finalapproach.airspeed indicatorairspeed indicator /�eəspi�d�ndketə/ noun a primary cockpit orflight deck instrument which shows thepilot the speed of the aircraft in relationto the air around it � Airspeed is shownin knots on the airspeed indicator.Abbreviation ASI

COMMENT: The position of the pitottube and the attitude of an aircraft canaffect the accuracy of the airspeedindicator. Aircraft operatinghandbooks usually have a table tohelp pilots calculate calibratedairspeed (CAS).

air stationair station /�eə �steʃ(ə)n/ noun asmall airfield with facilities for themaintenance of aircraftairstreamairstream /�eəstri�m/ noun the flowof air caused by the movement of theaircraft through the air � Pressure isbuilt up inside the pitot tube by the air-stream.

COMMENT: Unlike airflow, airstreamdoes not refer to the movement of airaround the airframe and itsaerodynamic effect.

airstripairstrip /�eəstrp/ noun a place for air-craft to take off and land that has nofacilities and is often temporaryair taxiair taxi /�eə �t�ksi/ noun a small com-mercial aircraft used for short flightsbetween places not on a regular airlineroute


air terminal 14air terminalair terminal /�eə �t%�mn(ə)l/ noun 1.an airport building with a range of facil-ities where passengers check in beforeboarding their plane and where theyarrive when their plane lands 2. a build-ing in a city for receiving passengerswho are being transported to or from anairport by train or busair terrorismair terrorism /�eə �terərz(ə)m/noun violent actions that aim to frightenor kill passengers, disrupt air services,or damage or destroy aircraft in anattempt to achieve a political objectiveair-tightair-tight /�eə tat/ adjective closed orsealed so that air cannot get in or outair-to-airair-to-air /�eətə |�eə/ adjective betweenone airborne aircraft and another � air-to-air communications � air-to-aircommunications communicationsbetween one airborne aircraft andanotherair to air refuelling areaair to air refuelling area /�eə tə �eəri�|�fju�əlŋ �eəriə/ noun an area of air-space in which tanker aircraft are per-mitted to refuel other aircraft in flight.Abbreviation AARAair-to-ground visibilityair-to-ground visibility /�eə tə�$raυnd �vz |�blti/ noun a descrip-tion of how easily seen an object on theground is from the air � Glare caused byreflection of sunlight from the top of alayer of fog or haze can seriouslyreduce the air-to-ground visibility.air-to-surfaceair-to-surface /�eə tə �s%�fs/ adjec-tive directed from a flying aircraft to apoint on the groundair trafficair traffic /�eə �tr�fk/ noun aircraftoperating in the air or on the airport sur-face � Students practising circuit flyingneed to keep a very careful lookoutespecially at times when there is a lot ofair traffic.air traffic controlair traffic control /�eə �tr�fk kən |

�trəυl/ noun a service that oversees andguides the movements of aircraft andprovides for the safe and efficient flowof air traffic � Controllers in the towerprovide an air traffic control service foraircraft in the air around the airfield.Abbreviation ATC

COMMENT: Air Traffic Control’s mainfunction is to maintain separationbetween aircraft operating within

Instrument Flight Rules (IFR), but italso provides a service to aircraftusing Visual Flight Rules (VFR).Ground control is for aircraft taxiing toand from runways. The tower controlsaircraft around an airport, clearingthem for take-off or landing. Departureand approach controls monitor andcontrol aircraft around the airport, anden route centres control trafficbetween airports.

air traffic controllerair traffic controller /�eə �tr�fkkən |�trəυlə/ noun a person who worksin air traffic control and whose maintask is to ensure correct separation ofaircraft in all phases of flight � The airtraffic controller approved the emer-gency landing. Abbreviation ATC. �

controllerair traffic movementsair traffic movements /�eə �tr�fk�mu�vmənts/ plural noun the numberof aircraft taking off and landing � anincrease in air traffic movementsairwayairway /�eəwe/ noun an area of thesky, usually rectangular in cross-sec-tion, along which civil aircraft fly fromplace to place � Airways provide a highdegree of safety by ensuring adequateseparation between aircraft. � Aircraftinside an airway are controlled by ATC.(NOTE: Airways are usually 10 nm widewith a centreline joining navigationalbeacons.)AirwaysAirways /�eəwez/ noun a commer-cial company operating flights (NOTE:Usually used in the names of compa-nies, e.g. British Airways, South AfricanAirways)airworthinessairworthiness /�eə |�w%�ðinəs/ nounthe state of an aircraft with regard towhether it can fly safely, as determinedby a national certifying authorityairworthiness directiveairworthiness directive noun aregulation issued by an aviation author-ity when a problem has been identifiedwith a particular aircraft part. Abbrevi-ation ADairworthyairworthy /�eəw%�ði/ adjective meet-ing the standards of a national certify-ing authority � It is the pilot’s responsi-bility to ensure that the aircraft isairworthy.AISAIS abbreviation aeronautical informa-tion services


15 allowanceaisle

aisle /al/ noun a long passagewaybetween the seats in the passenger cabinof an airliner � aisle seat a seat which isby an aisle, as opposed to a window seatalarm

alarm /ə |�lɑ�m/ noun 1. fear or worry �If the ammeter shows a high level ofcharge after start-up, it is quite normaland no cause for alarm. 2. a warningsound or light � In the event of fire oroverheat, the control unit will producean alarm. � verb to frighten or worry �

Severe turbulence may alarm passen-gers.alert

alert /ə |�l%�t/ adjective fully awake,watchful and ready to deal with any sit-uation � The crew must be alert at alltimes to the possibility of hijacking,bombs and stowaways. � noun a signal,warning everyone to be alert � to be onthe alert to be watchful and ready foranything that may happen � verb towarn � It is the cabin staff ’s responsibil-ity to alert the flight crew if they seesmoke coming from an engine.alight

alight /ə |�lat/ adjective on fire �

Although the passenger thought he hadextinguished his cigarette, it was stillalight when he threw it into the wastedisposal bin. � verb (formal) 1. (of peo-ple) to leave or get off an aeroplane � Atsome airports, passengers alight ontothe apron when they leave the aircraft.2. (of aircraft) to land � An aeroplanemay not fly over a city below such aheight as would allow it to alight in theevent of an engine failure.align

align /ə |�lan/ verb 1. to position alongan axis or line � The nose wheel must bealigned in a fore and aft direction dur-ing retraction. 2. to set in a correct posi-tion in relation to something else �

Aligned white marks on the wheel andtyre indicate that there is no creep.alignment

alignment /ə|�lanmənt/ noun 1.position in relation to an axis or a line �to check the alignment of somethingto make sure it is in the correct positionrelative to an axis or line � to maintainalignment with the runway to keepthe aircraft on the imaginary extendedcentre line of the runway 2. correctposition in relation to something else �

out of alignment not aligned as itshould bealkalinealkaline /��lkəlan/ noun a substancewith a pH value of more than 7alleviatealleviate /ə |�li�viet/ verb to reduce orlessen the harmful effect of something �Anti-icing additives are available toalleviate the problem of icing.alleviationalleviation /ə |�li�vi|�eʃ(ə)n/ noun areduction or lessening of the harmfuleffect of something � Deep, regularbreathing may provide some alleviationfrom stress.allocateallocate /��ləket/ verb to providesomething particular for a given pur-pose � Special seats are allocated tomothers with small children.allocationallocation /��lə |�keʃ(ə)n/ noun theprovision of something particular for agiven purpose � At the check-in desk,airline staff are responsible for the allo-cation of seats to passengers. � fre-quency allocation the frequency orrange of radio frequencies set aside fora particular use � The frequency alloca-tion for VOR is 108–117.975 MHz.allowallow /ə|�laυ/ verb to enable, to permitor to authorise � An engine should berun at low rpm after flight to allowengine components to cool. � Addi-tional fuel is carried to allow for hold-ing en route. � Passengers are notallowed to smoke on some aeroplanes.allowableallowable /ə |�laυəb(ə)l/ adjective per-mitted or authorised � maximum allow-able weight � maximum allowable tyrepressureallowanceallowance /ə |�laυəns/ noun 1. consid-eration for possibilities or changing cir-cumstances � to make allowances forto take into account � When estimatingflight duration, make allowances fortaxiing time. 2. something such asmoney given at regular intervals or for aspecific purpose � a travel allowance tocover hotel and restaurant bills. 3. theamount of something that somebody isallowed to have

‘…with many four and six seat aircraft, itis not possible to fill all the seats, use themaximum baggage allowance, fill all thefuel tanks and remain within the approvedcentre of gravity limits’ [Civil Aviation


alloy 16

Authority, General Aviation Safety SenseLeaflet]

alloyalloy /��lɔ/ noun a mixture of metals� an alloy of aluminium and lithiumaloftaloft /ə |�lɒft/ adjective up in the airalteralter /�ɔ�ltə/ verb to change, modify oradjust � If there is a risk of collision,alter course to the right. � If the rate ofdescent is too low, alter the throttle set-ting accordingly. � The rudder linkagewas altered to comply with certificationrequirements.alterationalteration /�ɔ�ltə |�reʃ(ə)n/ noun 1. achange, modification or adjustment � Itwas discovered that alterations hadbeen made to the log book. � As a resultof the accident, alterations were madeto the design of the carburettor heat sys-tem. 2. the act of making changes, mod-ifications or adjustments � headingalteration the act of making of headingcorrectionsalternate

alternate adjective /ɔ�l |�t%�nət/ 1.every other � A, c, e, and g are alternateletters, as are b, d, f, h, etc. � alternatedays every other day � There are out-ward flights on alternate days, i.e. onMondays, Wednesdays and Fridays. 2.US same as alternative � noun /ɔ�l|

�t%�nət/ an aerodrome of second choiceto be used if the aircraft cannot belanded at the aerodrome of first choicebecause of bad weather, etc. � The pointof no return is calculated before depar-ture to cover the chance that both theterminal airfield and its alternatebecome unavailable during flight. �

verb /�ɔ�ltənet/ to happen in turns �Captain Smith and Captain Jonesalternate as CFI on a daily rota eachcaptain has one day on duty as CFI fol-lowed by a day off, on which the othercaptain acts as CFIalternating currentalternating current /�ɔ�ltənetŋ�k�rənt/ noun an electric current whichreverses its direction at regular intervals� Resistance to alternating currentremains almost constant and is inde-pendent of frequency. Abbreviation ACalternativealternative /ɔ�l|�t%�nətv/ adjectivereferring to another or a second possi-bility � A turbine bypass, in the form ofan alternative exhaust duct is fitted with

a valve. � an alternative means ofdoing something another or differentway of doing something � noun anotherchoice or possibility � In some emer-gency situations the pilot may have noalternative but to force-land the aircraftas soon as possible.alternatoralternator /�ɔ�ltənetə/ noun a typeof generator designed to produce ACpoweraltimeteraltimeter /��ltmi�tə/ noun a radioinstrument for measuring vertical dis-tance or altitude � altimeter check aroutine check to ensure that the altime-ter pressure setting is correct � altime-ter display the display of altitude infor-mation, which can be given in analogueor digital form. � pointeraltitudealtitude /��lttju�d/ noun the verticaldistance between an aircraft, or a pointor a level, and mean sea-level � to losealtitude to descend from higher tolower altitude � cabin altitude the arti-ficial altitude created in the cabin bypressurisationalto-alto- /�ltəυ/ prefix at a moderate orhigh altitudealtocumulusaltocumulus /�ltəυ |�kju�mjυləs/noun small white cumulus cloudswhich form as a layer at moderate alti-tude, usually meaning fair weather.Compare stratocumulusaltostratusaltostratus /�ltəυ |�strɑ�təs/ noun auniform layer cloud at moderate alti-tudealuminiumaluminium /��lə |�mniəm/ noun astrong, light metal used in the construc-tion of aircraft (NOTE: The US English isaluminum.)

COMMENT: In recent years, aluminiumhas been increasingly replaced by theuse of composite materials in theconstruction of different types ofaircraft, from small home-built lightaircraft to transport aircraft such as theAirbus A320.

aluminumaluminum /ə|�lu�mnəm/ noun USsame as aluminiumAMAAMA abbreviation approach monitor-ing aidamberamber /��mbə/ adjective an orange oryellow colour � An amber light flasheson the instrument panel. (NOTE: Amber


17 analogue

is often used to describe the colour ofthe yellow light in traffic signals.)ambientambient /��mbiənt/ adjective refer-ring to the surrounding atmosphericconditions � Fresh ambient air is routedinto the cabin. � ambient temperaturethe temperature outside the aircraftambient pressureambient pressure /��mbiənt�preʃə/ noun the pressure outside theaircraftambiguityambiguity /��mb|�$ju�ti/ nounsomething heard or seen which can beunderstood in more than one way, thusresulting in possible confusion � toavoid ambiguity to avoid misunder-standing or confusion � Correct use ofR/T phraseology avoids ambiguity.ambiguousambiguous /�m |�b$juəs/ adjectiveable to be understood in more than oneway � It is important that R/T transmis-sions are not ambiguous.AMDAMD abbreviation amendmentamendamend /ə|�mend/ verb to change,update, improve or correct something �he amended the entry in his log bookhe corrected or changed the entry in hislog bookamendmentamendment /ə|�mendmənt/ noun achange, updating, improvement or cor-rection made, e.g., to a document orprocedure � When a terminal aero-drome forecast requires amendment,the amended forecast is indicated byinserting AMD after TAF.ammeterammeter /��mi�tə/ noun an instru-ment for measuring amperes in order togive the strength of an electric current �The centre-zero ammeter tells the pilotthe status of the aircraft battery.ampamp /�mp/ abbreviation ampereamperageamperage /��mpərd"/ noun thestrength of an electric current expressedin amperes � Measuring the amperageof a motor can give a rough estimate ofthe load on the motor.ampereampere /��mpeə/ noun a unit of elec-tric current equal to one volt flowingthrough an impedance of one ohm � a13-amp fuse � Current flow is measuredin amperes. Abbreviation amp �ampere hours number of amperes perhour � Battery capacity is rated inampere hours.

ampleample /��mpəl/ adjective plenty of �

During the course you will have ampleopportunity to demonstrate your skill. �ample time plenty of timeamplificationamplification /��mplf|�keʃ(ə)n/noun the act of increasing the strengthof an electrical signal � Amplification ofthe signal increases the volume.amplifieramplifier /��mplfaə/ noun an elec-tronic device for increasing the strengthof an electrical signal � If the powersupply from the amplifier to the gaugefails, the needle slowly falls to zero.amplifyamplify /��mplfa/ verb to increasethe strength of an electrical signal � Anelectric current is amplified and thentransmitted. (NOTE: amplifies – ampli-fying – amplified)amplitudeamplitude /��mpltju�d/ noun themaximum variation of a vibration oroscillation from the position of equilib-rium � to calculate fuel required, multi-ply the duration of the flight by the con-sumption of the engine at the requiredpowerAMSAMS abbreviation aeronautical mobileserviceAMSLAMSL abbreviation above mean sealevelAMSSAMSS abbreviation automatic mes-sage switching systemanabaticanabatic /�nə|�b�tk/ adjectivereferring to a warm flow of air travel-ling up a hillside or mountainside.Compare katabaticanabatic windanabatic wind /��nəb�tk �wnd/noun a wind current, caused by solarheating of the land, that rises up a south-facing mountainside � South-facingslopes are most suitable for the ana-batic wind. Compare katabatic windanaloganalog /��nəlɒ$/ adjective same asanalogueanalogousanalogous /ə |�n�lə$əs/ adjectivesimilar or comparable to � Isobars areanalogous to contour lines.analogueanalogue /��nəlɒ$/ adjective 1. rep-resenting a quantity or signal that variescontinuously by means of a physicalapparatus such as a dial and pointer �

The electronic centralised aircraft mon-itor (ECAM) does not have analogue


analyse 18

presentation of engine information. 2. �analogue display (on a clock) a tradi-tional hands and face display on a clockor dial. Compare digital displayanalyse

analyse /��nəlaz/, analyze verb tobreak down into parts and study veryclosely � to analyse fuel to separatefuel into its different parts to find outwhat it consists of � to analyse a chartto examine a chart in detailanalysis

analysis /ə|�n�ləss/ noun breakingdown a substance into its parts in orderto study them closely � At a crash site,samples of materials are removed foranalysis. (NOTE: The plural form is anal-yses /ə|�n�lsi�z/ .) � chart analysiscareful study of chartsanchor

anchor /��ŋkə/ noun a device con-nected to and dropped from a boat inorder to prevent the boat from movingin the water � verb to drop an anchor toprevent the boat from movinganemograph

anemograph /ə |�nemə$rɑ�f/ nounan instrument which maintains a contin-uous recording of wind direction andspeed on a graph � The anemographgives a continuous recording of windvelocity which is displayed on a chartand reveals gusts, squalls and lulls.anemometer

anemometer /�n|�mɒmtə/ noun aninstrument, usually attached to a build-ing, with three or four ‘cups’ whichrotate with the wind thus providingwind-speed information � The strengthof the wind can be seen by the speedwith which the anemometer rotates.aneroid

aneroid /��nərɔd/ adjective not con-taining or using liquidaneroid barometer

aneroid barometer /��nərɔd bə |

�rɒmtə/ noun a barometer which usesan aneroid capsule to sense atmosphericpressure changesaneroid capsule

aneroid capsule /��nərɔd�k�psju�l/ noun a thin flexible cylin-drical box, usually made of metal,which has most of the air removed fromit and which expands and contracts withchanges in atmospheric pressure � Theaneroid capsule in the barometer isconnected to a system of levers whichoperate a pointer.

aneroid switch

aneroid switch /��nərɔd swtʃ/noun a switch operated by an aneroidcapsuleangle

angle /��ŋ$əl/ noun the difference indirection between two lines or surfacesmeasured in degreesangle of attack

angle of attack /��ŋ$(ə)l əv ə|�t�k/noun the angle formed between the rel-ative airflow and the chord line of theaerofoil

COMMENT: The angle of attack isrelated to the flight path of the aircraft,not to the angle the wing makes withthe horizontal. If the angle of attackbecomes too great, the smooth airflowover the upper surface of the wing willbreak down. If no corrective action istaken by the pilot, there will be asudden loss of lift and the aircraft willstall.

angle of incidence

angle of incidence /��ŋ$(ə)l əv�nsd(ə)ns/ noun the angle formedbetween the chord-line of the main-plane and the horizontal when the air-craft is in the rigging positionangle of inclination

angle of inclination /��ŋ$(ə)l əv�nkl |�neʃ(ə)n/ noun the angle formedbetween a sloping path or surface and areference point or line which is eitherhorizontal or vertical � Between anytwo meridians there is an angle of incli-nation one to the other which varieswith latitude.angular

angular /��ŋ$jυlə/ adjective refer-ring to or forming an angle � The angu-lar difference between the direction ofmagnetic north and compass north iscalled variation.anneal

anneal /ə|�ni�l/ verb to heat and allowto cool slowly in order to strengthen �

Sheet and plate magnesium areannealed at the rolling mill.annotate

annotate /��nətet/ verb to add notesto an existing document, book, chart,etc. � He annotated his report after hewas asked to give the exact time of theincident. � Variation is annotated eastor west according to the direction ofchange.annotation

annotation /��nə |�teʃ(ə)n/ noun theact of adding notes to a document,book, chart, etc., or the notes added


19 anti-icing fluidannounceannounce /ə |�naυns/ verb to statesomething publicly or officially � Brit-ish Airways announce the departure offlight BA152 to New York.announcementannouncement /ə |�naυnsmənt/noun a public statement � The captainmade a public address (PA) systemannouncement asking passengers toremain seated.annualannual /��njuəl/ adjective 1. happen-ing once a year � annual inspection aninspection that happens once a year 2.over a period of one year � Overloadoperations should not exceed 5% ofannual departures.annularannular /��njυlə/ adjective shapedlike a ringannunciationannunciation /ən�nsi|�eʃ(ə)n/ nounan announcement or indication on theannunciator panel � failure annuncia-tion signals on the annunciator panelindicating the failure of a systemannunciatorannunciator /ə |�n�nsietə/ noun adevice which gives off a sound or lightto indicate which of several electricalcircuits is active � An annunciatorpanel may contain a precise warning.anodeanode /��nəυd/ noun a positive poleor electrode � The positive connector ofa battery is usually called the anodeand is indicated by the sign +.anodiseanodise /��nədaz/, anodize verb tocoat or cover by using electrolysis �

Anti-corrosion treatment includes theanodizing of aluminium parts.anomalousanomalous /ə |�nɒmələs/ adjectivereferring to something unusual, unex-pected or otherwise departing fromwhat is the normal order or range � ananomalous instrument reading anunusual instrument reading which mayrequire further investigationanomalyanomaly /ə |�nɒməli/ noun somethingunusual, unexpected or otherwise notwithin the normal order or range � Anyanomalies in the localiser will bedetected during calibration.anoxiaanoxia /� |�nɒksiə/ noun a state inwhich no oxygen reaches the body tis-sues, resulting in death. � hypoxia

COMMENT: Anoxia is a complete lackof oxygen and can, of course, be fatal.

Hypoxia is a lack of sufficient oxygen,the symptoms of which are sometimesdifficult to detect.

antennaantenna /�n|�tenə/ noun US same asaerialanti-anti- /�nti/ prefix against, opposing �

anti-icing � anticlockwise � anti-corro-sionanticipateanticipate /�n|�tspet/ verb to real-ise what is likely happen and do what isnecessary in readiness � during take-offs, pilots should anticipate anengine failure pilots should thinkahead and be ready to act immediatelyif an engine fails during take-offanticipationanticipation /�n |�ts|�peʃ(ə)n/ nouna state in which you realise what islikely to happen and do what is neces-sary in readinessanticipation of landmarksanticipation of landmarks /�n|

�tspeʃ(ə)n əv �l�ndmɑ�ks/ noun theaction of watching out for landmarks,which you know from flight planningshould be visible at a particular stage ofa flightanticlockwiseanticlockwise /��nti|�klɒkwaz/adjective, adverb referring to a circularmovement in the opposite direction tothe hands of a clock � Turn the nut anti-clockwise to loosen it. Opposite clock-wiseanti-collisionanti-collision /��nti kə|�l"(ə)n/adjective helping to prevent collisionsanti-collision lightanti-collision light /��nti kə|

�l"(ə)n lat/ noun a flashing white lighton an aircraftanti-corrosionanti-corrosion /��nti kə |�rəυ"(ə)n/adjective protecting against corrosion,especially rust � an anti-corrosiontreatmentanticycloneanticyclone /��nti |�sakləυn/ nounan area of high atmospheric pressure,usually associated with fine dry weatherin summer and fog in winter � Windscirculate round an anticyclone clock-wise in the northern hemisphere andanticlockwise in the southern hemi-sphere.anti-icinganti-icing /��nti �asŋ/ adjectivepreventing icing � anti-icing additiveanti-icing fluidanti-icing fluid /��nti �asŋ �flu�d/noun a fluid which prevents icing


anti-skid 20anti-skid

anti-skid /��nti �skd/ adjectivedesigned to prevent skiddinganvil

anvil /��nvl/ noun a metal blockwhich ends in a point, has a roundedbottom and a flat top, and on whichhorseshoes, etc., are made � A cumulo-nimbus cloud has a characteristic anvilshape.anvil cloud

anvil cloud /��nvl klaυd/ noun acloud, usually a large dark thunder-cloud, which has the shape of an anvilA/P

A/P abbreviation 1. airport 2. autopilotapart

apart /ə |�pɑ�t/ adverb separated fromone another � The jets were only 200feet apart, vertically.aperture

aperture /��pətʃə/ noun an opening� Any aperture or cut-out in the fuse-lage structure must be speciallystrengthened.APHAZ

APHAZ abbreviation aircraft proxim-ity hazardAPP

APP abbreviation 1. approach 2.approach controlapparent

apparent /ə |�p�rənt/ adjective 1.obvious, clear � It became apparentthat carbon monoxide was entering thecabin. � from the above, it will beapparent that … from the above, itwill be clear that … 2. seeming orappearing to be � an apparent failure ofthe system � The ILS showed an appar-ent deflection to the right.appear

appear /ə |�pə/ verb 1. to come intoview � Another aircraft appeared on theradar screen. 2. to seem to be �

Although air may appear to be still, it isin fact, moving.appearance

appearance /ə |�pərəns/ noun 1. aninstance of being seen or coming intoview � The appearance of the passen-ger on the flight deck surprised thecrew. 2. the way something looks � Itmay be difficult to recognise a particu-lar stretch of coast in an area simply byits appearance.appendix

appendix /ə |�pendks/ noun a sectioncontaining additional information,often found at the end of a book, etc. �

Charts are reproduced as an appendixto the map section. (NOTE: The pluralform is appendices.)

applicable

applicable /ə |�plkəb(ə)l/ adjective 1.relevant or appropriate � rule 24 is notapplicable in this case rule 24 cannotbe used in this case 2. suitable, neces-sary, appropriate � Emergency systemsare checked when applicable.application

application /��pl |�keʃ(ə)n/ noun 1.a formal request, often on paper, foremployment � application form a formto be filled out by a person looking for ajob, and sent back to the organisationoffering the job 2. the act of putting asubstance onto something � the appli-cation of a coat of paint the coveringof something with a coat of paint 3. theact of using something, e.g. an ability,to carry out a task � When an accidentoccurs, the application of knowledgeand skills is important.apply

apply /ə |�pla/ verb 1. � to apply for ajob to formally ask for employment �

He applied for the post of chief engineerbut was not successful. 2. to put on � toapply a coat of paint � Apply a plasterto the skin. 3. to use something to carryout a task � Apply the same method asin the example. 4. to be relevant or relateto � The rules which apply to the meas-urement of wind velocities on isobariccharts apply equally to contour charts.(NOTE: applying – applied)appreciable

appreciable /ə |�pri�ʃəb(ə)l/ adjective1. possible to measure � Appreciableweakening may be permitted withoutrisk of failure. 2. considerable, large insize or amount � there is an apprecia-ble difference between statute milesand nautical miles there is a big differ-ence between statute miles and nauticalmilesappreciate

appreciate /ə |�pri�ʃiet/ verb 1. tounderstand or recognise the importanceor significance of something � The mapreader is in a position to appreciate therelative values of the features seen onthe ground. 2. to increase in value � Thevalue of the building has appreciated by100% in 10 years. Opposite depreciate3. to be thankful or grateful for some-thing � The student appreciated theextra help given by the instructor.appreciation

appreciation /ə |�pri�ʃi |�eʃ(ə)n/ noun1. understanding � It is essential to have


21 APRX

an appreciation of the basic gas laws. 2.an increase in value � There has been anappreciation of 100% in the value of thebuilding in 10 years. Opposite depreci-ation 3. thankfulness, gratitude � Aftergaining her private pilot’s licence, thenewly-qualified pilot showed her appre-ciation by sending a letter of thanks toher instructor.approach

approach /ə |�prəυtʃ/ noun 1. a pathtowards something � The approach tothe terminal was blocked by an over-turned lorry. 2. the descent of an air-craft towards the place where it intendsto land. Abbreviation APP 3. a way ofachieving or doing something � to takea different approach to a situation todeal with or to manage a situation in adifferent way � verb 1. to move nearerin place or time to something � The air-craft is approaching a danger area. �nightfall is approaching it will soon bedark 2. to have a particular mental atti-tude towards something � Heapproaches his studies with greatenthusiasm. 3. to speak to or get intouch with somebody � You mustapproach the chief flying instructorregarding your request for a week’s hol-iday.approach control

approach control /ə |�prəυtʃ kən |

�trəυl/ noun a control station in an airtraffic control centre that guides an air-craft while it is making its approachapproach monitoring aid

approach monitoring aid /ə |

�prəυtʃ �mɒntərŋ �ed/ noun aninstrument or system that helps an airtraffic controller to track the positionand movements of an aircraft during itsapproach. Abbreviation AMAapproach path

approach path /ə|�prəυtʃ pɑ�θ/noun the course taken by the aircraft inpreparation for landingapproach plate

approach plate noun a documentissued by an aviation authority whichprovides detailed information abouthow to land at a given airport in verypoor visibilityapproach to land

approach to land /ə |�prəυtʃ tə�l�nd/ noun the final stage of the flightwhen the aircraft is manoeuvred intoposition, relative to the landing area, inpreparation for landing � on the

approach to land, the aircraft reducesspeed and heightappropriateappropriate /ə|�prəυpriət/ adjectivesuitable or needed � appropriateaction the action that is needed to dealwith the situationappropriatelyappropriately /ə|�prəυpriətli/adverb in a way that it is suitable or nec-essary � to adjust the mixture appro-priately to adjust the mixture to suit theconditionsapprovalapproval /ə |�pru�v(ə)l/ noun permis-sion or agreement � with the captain’sapproval with the permission of thecaptain � to meet with the approval tobe approved by � The management’splans for restructuring the airline metwith the approval of the shareholders.approveapprove /ə |�pru�v/ verb 1. to allow oragree to something � The air traffic con-troller approved the emergency land-ing. 2. � to approve of to believe some-thing to be right or good � Nearlyeverybody approved of the new colourscheme for the furnishings. � hedoesn’t approve of women being air-line pilots he believes that it is wrongfor women to be airline pilotsapproxapprox /ə|�prɒks/ same as approxi-mate, approximatelyapproximateapproximate adjective /ə|

�prɒksmət/ not exact, around or about� an approximate distance of 60 nmabout 60 nautical miles � verb /ə|

�prɒksmet/ to be close to, to bearound (NOTE: Approximate can beshortened to approx or APRX (ICAO).)approximatelyapproximately /ə |�prɒksmətli/adverb not exactly, around or about �

Approximately 2,000 people work in theairport. (NOTE: Approximately can beshortened to approx or APRX (ICAO).)approximationapproximation /ə |�prɒks |�meʃ(ə)n/noun a calculation which is not exactbut near enough, a rough estimate � anapproximation of aircraft height arough estimate of aircraft heightapronapron /�eprən/ noun an area of tar-mac, concrete, etc., outside a hangar forparking aircraft (NOTE: The US term isramp.)APRXAPRX abbreviation (ICAO) 1. approxi-mate 2. approximately


APU 22APUAPU abbreviation auxiliary power unitaquaplaningaquaplaning /��kwəplenŋ/ nounsliding in an uncontrolled way over athin layer of water on the runway �

Aquaplaning is caused by a layer ofwater between the tyre and the runway.arbitraryarbitrary /�ɑ�btrəri/ adjectivedecided by chance rather than by care-ful logical thought, happening withoutplanning or at random � The statutemile is an arbitrary unit of measure-ment. (NOTE: The nautical mile is not anarbitrary unit: it is based on calculationswhich have a wider use. See arc.)arcarc /ɑ�k/ noun part of the circumfer-ence of a circle � A nautical mile is thelength of an arc on the Earth’s surfacesubtended by an angle of one minute atthe centre of the Earth. � verb to jumpacross a gap � The spark arcs from oneelectrode to another. � The condenserprevents spark plugs from arcing. � gapArcticArctic /�ɑ�ktk/ adjective referring tothe area around the North Pole � coldArctic air cold air from the Arctic � theArctic Circle a parallel running roundthe Earth at latitude 66°32N, to thenorth of which lies the Arctic region �

noun � the Arctic the area of theEarth’s surface around the North Pole,north of the Arctic Circle � The aircraftflew over the Arctic.areaarea /�eəriə/ noun 1. a defined part ofa surface 2. a region � area forecasts aweather forecast for a region ratherthan, e.g., an aerodromearea control servicearea control service /�eəriə kən |

�trəυl �s%�vs/ noun a unit that providesair traffic control services to flightswithin the area for which it is responsi-blearea navigationarea navigation /�eəriə �n�v|

�$eʃ(ə)n/ a method of navigation thatpermits aircraft to operate on anydesired flight path within the area cov-ered by ground-based navigational aids,self-contained navigational aids or acombination of the two. AbbreviationRNAVargumentargument /�ɑ�$jυmənt/ noun 1. afactor � QNH is the pressure at stationlevel reduced to sea level using argu-ments of station height and an interna-

tional standard atmosphere. 2. a verbaldisagreement � to have an argument todisagree openly and verbally withsomebody � The investigation revealedthat there had been an argumentbetween the commander and the copilotabout the advisability of continuingwith the final approach to land. 3. a rea-son � One of the arguments in favour ofbuilding the new terminal is theincrease in opportunities of employ-ment for the local residents.aridarid /��rd/ adjective very dry � aridterrain desert � an arid, sub-tropicalclimate a hot, dry climatearisearise /ə |�raz/ verb to come into being,to happen, to show up or to appear �

Should any problems arise, report backto me immediately. (NOTE: arising –arose – arisen)armarm /ɑ�m/ noun 1. a device similar infunction to a human arm, operating as alever 2. the horizontal distance from areference point to the centre of gravity �The principle of the arm is used inweight and balance calculations for anaircraft. � verb to make ready for actionor use � Door-mounted escape slidesare armed before flight.armaturearmature /�ɑ�mətʃə/ noun the rotat-ing coils of an electric motor or dynamo� Secondary windings are wound overthe primary windings and the wholeassembly is known as an armature.ARRARR abbreviation arrivalarrangearrange /ə |�rend"/ verb 1. to organ-ise, to plan and prepare � to arrange ameeting 2. to put in special position �

Charts should be numbered andarranged in order of use. � A series ofdipoles are arranged in a circle.arrangementarrangement /ə |�rend"mənt/ noun1. a plan � The arrangements for theVIPs are being handled by the publicrelations department. 2. the relativepositions of a number of different parts� The diagram shows a simple arrange-ment of pistons, cylinders and pipes.arrayarray /ə |�re/ noun an arrangement ofantennas � The localiser antenna arrayis very wide.arrestarrest /ə |�rest/ verb 1. to stop or to pre-vent something from happening � to


23 assess

arrest the spread of a fire to stop thefire spreading 2. to hold somebody forbreaking the law � He was arrested atthe airport. � noun the act of holdingsomebody for breaking the law � Hisarrest was unexpected.arresterarrester /ə |�restə/ noun a device orsubstance which prevents or stopssomething from happeningarrivalarrival /ə |�rav(ə)l/ noun the act ofreaching somewhere. AbbreviationARR � Gulf Air announce the arrivalof flight GF147 from Abu Dhabiflight GF147 from Abu Dhabi has justlandedarrivalsarrivals /ə |�rav(ə)lz/ noun the part ofan airport that deals with passengerswho are arrivingarrivearrive /ə|�rav/ verb to reach some-where � the flight from Tokyo arrivedat 8.30 the flight from Tokyo landed at8.30arrowarrow /��rəυ/ noun a painted orprinted sign which points to something� Non-return valves are marked with anarrow which shows the direction offlow.arrow conventionarrow convention /��rəυ kən |

�venʃ(ə)n/ noun an agreed method ofusing arrows when drawing wind trian-glesarticlearticle /�ɑ�tk(ə)l/ noun an object, anitem � loose articles things which maymove during flight and cause problemsartificialartificial /�ɑ�t |�fʃ(ə)l/ adjective notnatural, made by humans � The smallneedle indicates cabin altitude or theartificial altitude created by the pres-surisation system.artificial horizonartificial horizon /�ɑ�tfʃ(ə)l hə |

�raz(ə)n/ noun an instrument that dis-plays the degree of pitch or bank of anaircraft relative to the horizonascendascend /ə|�send/ verb to rise, to go ormove upwards � Hot air ascends. � inascending order in order of number orrank with the smallest or less importantat the bottom and the largest or moreimportant at the top. Opposite descendascentascent /ə |�sent/ noun a rise, a slowupward movement � the forced ascentof air over high ground � In a stableatmosphere where the ascent of air is

forced, precipitation is mostly light andoccasionally moderate.ascertainascertain /��sə |�ten/ verb to findout, to make certain � During pre-flightchecks, control surfaces should bemoved by hand to ascertain that theyhave full and free movement.ASDEASDE abbreviation airport surfacedetection equipmentASIASI abbreviation airspeed indicatorASMIASMI abbreviation aerodrome surfacemovement indicatoraspectaspect /��spekt/ noun 1. a part of aproblem or subject � Vertical motion isan important aspect of meteorology. �safety aspects matters related to safety2. the view from a particular position �

The aspect of the runway on finalapproach helps the pilot to judge heightand progress.aspect ratioaspect ratio /��spekt �reʃiəυ/ nounthe ratio of the length of an aircraft’swing to the average distance betweenthe front and back edge of the wing(NOTE: Aircraft that operate at lowspeeds, for example gliders, need ahigh aspect ratio and have long narrowwings. Supersonic aircraft need a lowaspect ratio, which is created by swing-ing the wings back.)asphyxiationasphyxiation /əs |�fksi|�eʃ(ə)n/noun unconsciousness or death causedby lack of oxygen � Fire may result inthe cabin being filled by smoke causingasphyxiation.ASRASR /�e es �ɑ�/ abbreviation 1. airportsurveillance radar 2. altimeter settingregionassembleassemble /ə |�semb(ə)l/ verb 1. to puta number of parts together � The partsare made in different countries but theplane is assembled in France. 2. togather together � Passengers shouldassemble in the departure lounge wherean airline representative will meetthem.assemblyassembly /ə |�sembli/ noun 1. some-thing that is made up of smaller parts 2.the act of putting parts together to makea whole � Final assembly of the A320takes place in France.assessassess /ə|�ses/ verb to check, estimateor find out � Cabin crew must assess if


assessment 24

their exits are usable. � to assess a sit-uation to consider all aspects of a situ-ationassessmentassessment /ə |�sesmənt/ noun ajudgement on a situation based on care-ful thought � The captain’s assessmentof factors such as aircraft damage, pas-senger-load, fire, etc., will affect thedecision on whether to evacuate theaeroplane or not.assignassign /ə |�san/ verb to set apartbeforehand or allocate for a specificpurpose � assigned seats seats selectedbeforehand for particular people � Crewsit in their assigned seats. � Individualcarriers assign codes to aircraft.assist

assist /ə |�sst/ verb to help � If youhave any difficulty, cabin staff willassist you. � When evacuating the air-craft, hand signals by cabin staff assistin directing passengers to the exits. �

powerassistanceassistance /ə |�sst(ə)ns/ noun help �to require assistance to need help � Ifa pilot requires assistance, they shouldcontact ATC. � to provide assistance togive helpassociateassociate /ə|�səυsiet/ verb to comewith or be linked to something else �

Turbulence is often associated withstrong winds. � The airport authorityhas to overcome a lot of problems asso-ciated with its plans to build a new ter-minal.associationassociation /ə |�səυsi|�eʃ(ə)n/ noun1. a group of people who organisethemselves into an official body withcommon objectives and a code of con-duct � British Air Line Pilots Associa-tion. 2. � in association with togetherwith � Rain-ice occurs only rarely overthe British Isles and is usually found inassociation with warm fronts.assumeassume /ə |�sju�m/ verb 1. to take astrue before there is proof � I assumethat she’s ill because she’s not at worktoday – but I may be wrong. 2. to sup-pose � for our studies we will assumethat the earth is a perfect sphere weknow that the Earth is not a perfectsphere but it helps if we accept, for thetime being, that it is � assuming (that)accepting or supposing that � Assuming

that the return flight from the point of noreturn to A is made on three engines,calculate the distance from D to thepoint of no return. 3. to take on, toundertake the duties of somebody � Thecopilot assumed control of the aircraftafter the captain was taken ill duringthe flight. 4. to take a particular bodilyposition � The correct technique ofusing the escape slides is to assume asitting position.assumption

assumption /ə |�s�mpʃ(ə)n/ noun anunderstanding or belief � The one-in-sixty rule is based on the assumptionthat one nautical mile subtends anangle of one (at a distance of 60 nauti-cal miles).asymmetric

asymmetric /��s |�metrk/, asym-metrical /��s |�metrk(ə)l/ adjectivenot identical or equal on each side of animaginary central dividing line. Oppo-site symmetricasymmetric flight

asymmetric flight /��smetrk�flat/ noun a condition in which oneengine, displaced from the aircraft’scentre-line is not workingasymmetric power

asymmetric power /��smetrk�paυə/ noun power on one side of theaircraft’s centre line onlyasynchronous

asynchronous /ə|�sŋkrənəs/ adjec-tive 1. not happening at the same time orrate � An asynchronous orbit is a 24-hour orbit which enables a satellite toremain overhead one part of the Earth’ssurface. 2. not in frequency or phaseasynchronous computer

asynchronous computer /e |

�sŋkrənəs kəm|�pju�tə/ noun a com-puter which does not process informa-tion according to the internal clockATA

ATA /�e ti� �e/ abbreviation actualtime of arrivalATC

ATC /�e ti� �si�/ abbreviation 1. airtraffic control 2. air traffic controllerATCC

ATCC abbreviation air traffic controlcentreATCRU

ATCRU abbreviation air traffic controlradar unitATD

ATD /�e ti� �di�/ abbreviation actualtime of departureATFM

ATFM abbreviation air traffic flowmanagement


25 attenuateATISATIS abbreviation Automatic TerminalInformation ServiceATMATM /�e ti� �em/ abbreviation air traf-fic managementatmosphereatmosphere /��tməsfə/ noun 1. amixture of gases in a mass surroundingthe earth � The surrounding atmospheremoves with the earth. 2. a unit of meas-urement of pressure

COMMENT: The main gases found inthe atmosphere are nitrogen andoxygen. The atmosphere contains lessthan 1% carbon dioxide and argon,and also traces of hydrogen, helium,krypton, neon, ozone and xenon.

atmosphericatmospheric /��tməs |�ferk/ adjec-tive referring to the atmosphere �

atmospheric densityatmospheric attenuationatmospheric attenuation/��tməsferk ə |�tenju |�eiʃ(ə)n/ nounthe weakening of a radio signal as itpasses through the airatmospheric pollutionatmospheric pollution/��tməsferk pə|�lu�ʃ(ə)n/ noun sameas air pollution � Solid particles in theair include dust, sand, volcanic ash andatmospheric pollution.atmospheric pressureatmospheric pressure/��tməsferk �preʃə/ noun normal airpressure on the surface of the earthatmospheric refractionatmospheric refraction/��tməsferk r|�fr�kʃən/ nounchange in direction of waves due to var-iations in temperature, pressure andhumidity, particularly at lower altitudesatomatom /��təm/ noun the smallestamount of a substance which can takepart in a chemical reaction � An atomconsists of a nucleus and electrons.atomicatomic /ə|�tɒmk/ adjective referringto atoms � atomic structure of matterthe structure of materials and sub-stances at their smallest levelatomisationatomisation /�təma |�zeʃn/, atomi-zation /��təma|�zeʃ(ə)n/ noun thereduction of liquids to a fine spray � Thefuel achieves fine atomisation underpressure.atomiseatomise /��təmaz/, atomize verb toreduce liquids to a fine spray � The fuelmust be atomised or vaporised to com-bine with the air to permit combustion.

ATPLATPL abbreviation Airline TransportPilot’s LicenceATSATS abbreviation air traffic servicesATSUATSU abbreviation air traffic serviceunitattachattach /ə |�t�tʃ/ verb to join or fixsomething to something � The icedetector is attached to the fuselage.attachmentattachment /ə |�t�tʃmənt/ noun 1.the act of joining or fixing something tosomething � The attachment of wingletsimproved the handling characteristicsof the aeroplane. 2. an accessory whichcan be attached � The video camera issold with a number of attachmentsincluding a carrying strap and a batterypack.attachment pointattachment point /ə |�t�tʃməntpɔnt/ noun a place on the airframewhere something such as an engine isattached by means of bolts � Additionalstrength is required for the power plantattachment points.attainattain /ə |�ten/ verb to reach, to achievesomething, often with difficulty � Inorder to attain a fuller understanding ofgas turbines, it is essential to knowsomething about basic gas laws.attemptattempt /ə |�tempt/ noun a try � Anyattempt to increase range by applyingmore power is of little or no benefit. �

verb to try � He attempted to landdespite the poor visibility but thendecided to divert to another airfieldwhere he landed safely.attendantattendant /ə|�tendənt/ adjectiveaccompanying something else � Fuelspillage and attendant fire risk must beminimised. � attendant problems asso-ciated problems � noun a personemployed to help members of the pub-licattentionattention /ə |�tenʃən/ noun the abilityor power to concentrate on something �The crew’s attention is alerted by anautomatic display. � attention pleaselisten carefully to what will be said �pay attention listen to the speaker andconcentrate on what is being saidattenuateattenuate /ə |�tenjuet/ verb to losepower or strength � A wave becomesattenuated or loses strength as rangeincreases.


attenuation 26attenuationattenuation /ə |�tenju |�eʃ(ə)n/ nounloss of strength � Atmospheric attenua-tion is negligible until the upper end ofthe UHF band when it increases rapidlyto limit the highest usable frequency toabout 10 GHz.attenuativeattenuative /ə |�tenjuətv/ adjectivebecoming weaker � Rain has an attenu-ative effect.attitudeattitude /��ttju�d/ noun 1. the posi-tion of the aircraft in the air in relationto the horizon � Angle of attack willvary with changes in engine speed andaircraft attitude. � nose down attitudethe attitude of the aircraft when the noseis at a lower level than the tail 2. a wayof thinking and feeling about or ofbehaving towards something or some-body � he has an excellent attitudetowards his training programme he ispositive and motivated in his trainingprogrammeattitude heading reference systemattitude heading reference sys-tem /��ttju�d �hedŋ �ref(ə)rəns�sstəm/ noun full form of AHRSattitude indicatorattitude indicator /��ttju�d�ndketə/ noun a flight instrumentthat gives the pilot information aboutthe position of the aircraft in the air inrelation to the horizon � In light air-craft, the attitude indicator is situatedon the instrument panel, directly infront of the pilot. � pitch, bank

COMMENT: The attitude indicator issometimes referred to as the ‘artificialhorizon’. In instrument flight training,the attitude indicator is the primaryreference instrument. It is positionedon the instrument panel directly in frontof the pilot.

attractattract /ə|�tr�kt/ verb 1. to cause todraw near � If two magnets, with unlikepoles are brought together, they willattract each other. � to attract atten-tion to behave in such a way that peoplewill notice you 2. to cause people towant to have or do somethingattractionattraction /ə |�tr�kʃən/ noun 1. aforce that draws things towards some-thing � The strength of the magneticforce will depend, amongst otherthings, on the magnitude of attraction atthe magnetic source. 2. a quality thatcauses people to want to have or do

something � The attraction of flyingwas the factor which made him decideto train as a pilot.attractive

attractive /ə|�tr�ktv/ adjective 1.referring to something you feel youwould like to have � After long talks, theprospective buyer made a financiallyattractive offer for the aircraft. 2. niceto look atATZATZ abbreviation aerodrome trafficzoneaudibleaudible /�ɔ�db(ə)l/ adjective possibleto hear � The fire detection systemshould contain an audible warningdevice.audio

audio /�ɔ�diəυ/ noun an audible soundor sound signal � The diagram shows anamplitude modulation case where thelower frequency of the audio is about300 Hertz.augmentaugment /ɔ�$ |�ment/ verb to makelarger by adding something � The seabreeze may augment the up-slopemotion of an anabatic wind.aural

aural /�ɔ�rəl/ adjective referring tohearing � The aural and visual alertswill continue until the crew take actionto cancel them. (NOTE: Aural is some-times pronounced /�aυrəl/ to show thedifference with oral.)authoriseauthorise /�ɔ�θəraz/, authorize verbto allow officially, to give permission �

A signature is required to authorise therepair.authorisedauthorised /�ɔ�θərazd/, authorizedadjective officially allowed, permitted �Aircraft with a maximum authorisedweight of 12,500 lb or less. � anauthorized person a person who hasbeen given power to act and performparticular tasks or dutiesauthoritativeauthoritative /ɔ� |�θɒrtətv/ adjec-tive in the manner of somebody withauthority, in a commanding way � crewmust act in an authoritative mannercrew must give firm instructions orordersauthority

authority /ɔ�|�θɒrti/ noun 1. com-plete control or power over something �While boarding, the captain has theauthority to ask an unruly passenger toleave the aircraft. 2. an official or gov-


27 average

ernment body with the power to makedecisionsauto-auto- /ɔ�təυ/ prefix automatic or auto-matedautogiroautogiro /�ɔ�təυ |�d"arəυ/ noun anaircraft that uses a propeller to produceforward motion and has an unpoweredhorizontal rotor for lift and stabilityautolandautoland /�ɔ�təυl�nd/ abbreviationautomatic landingautomateautomate /�ɔ�təmet/ verb to makee.g. a device or procedure automatic �automated systems systems whichhave been made less dependent ondirect human control or managementautomaticautomatic /�ɔ�tə |�m�tk/ adjective 1.done without needing to think � In theearly stages of training, student pilotshave to think about the use of the flyingcontrols, but after a while these actionsbecome automatic. 2. which works byitself without the need of an operator �

The normal activation method is auto-matic.automatic dependent surveillanceautomatic dependent surveil-lance /�ɔ�təm�tk d|�pendənt sə |

�veləns/ an electronic surveillance sys-tem that uses data that aircraft provideautomatically via a datalink and is ableto identify and track the aircraftautomatic direction finderautomatic direction finder/�ɔ�təmetd da|�rekʃ(ə)n �fandə/noun a radio navigation instrument thatreceives signals from non-directionalradio beacons � The needle on the ADFindicator points toward the selectedradio signal. Abbreviation ADFautomatic landingautomatic landing /�ɔ�təm�tk�landŋ/ noun automatic flight controlsystem capable of landing an aircraft‘hands-off.’ Abbreviation autolandautomatic mixture controlautomatic mixture control/�ɔ�təm�tk �mkstʃə kən |�trəυl/ nouna subsystem in a piston engine whichadjusts the flow of fuel to balancechanges in air densityautomatic pilotautomatic pilot /�ɔ�təm�tk�palət/ noun full form of autopilotAutomatic Terminal Information ServiceAutomatic Terminal InformationService /�ɔ�təm�tk �t%�mn(ə)l�nfə|�meʃ(ə)n �s%�vs/ noun a record-ing of information played continuouslyon a specified radio frequency which

gives pilots the current weather, runwayin use, etc. � Students listen to the ATISto practise their language skills. Abbre-viation ATISautomationautomation /�ɔ�tə |�meʃ(ə)n/ nounthe automatic operation or automaticcontrol of a piece of equipment, a proc-ess, or a system � Automation hasspeeded up baggage handling. � Auto-mation of throttle control has removedthe need for pilots to monitor airspeedso closely. � It is possible that the alter-nate source might provide a reducedlevel of automation.autopilotautopilot /�ɔ�təυpalət/ noun a sys-tem which automatically stabilises anaircraft about its three axes, restores theoriginal flight path following an upsetand, in some systems, causes the air-craft to follow a preselected airspeed,altitude or heading. Full form auto-matic pilot. Abbreviation A/Pauxiliaryauxiliary /ɔ�$ |�zliəri/ adjective sec-ondary, which is used when necessaryto help or substitute for something elseauxiliary gearboxauxiliary gearbox /ɔ�$ |�zliəri �$ə|

�bɒks/ noun a gear box which allowsmain engine power to be used for sec-ondary systemsauxiliary power unitauxiliary power unit /ɔ�$ |�zliəri�paυə �ju�nt/ noun a small jet engineused to generate electrical power forair-conditioning, etc., when the aircraftis parked on the ground. AbbreviationAPUauxiliary rotorauxiliary rotor /ɔ�$ |�zliəri �rəυtə/noun the tail rotor of a helicopteravailabilityavailability /ə |�velə|�blti/ noun thefact of being available � The status of anairport is determined by the availabilityof suitable navigation aids.availableavailable /ə |�veləb(ə)l/ adjectiveready for immediate use � On a multi-engine aircraft, all the fuel must beavailable for use by any engine.averageaverage /��v(ə)rd"/ adjective refer-ring to an average � For load sheet pur-poses, an average weight of the passen-gers and crew members may be used. �

noun the total divided by the number ofitems added � The average of 1, 5, 9, 10and 15 is 8 (1+5+9+10+15 = 40 ÷ 5 =8). � verb to reach a particular figure as


avert 28

an average � Brake temperatures aver-age around 500°C during normal oper-ations.avertavert /ə |�v%�t/ verb to avoid � To averta collision, he changed direction.AVGASAVGAS /��v$�s/ abbreviation avia-tion gasolineaviationaviation /�evi |�eʃ(ə)n/ noun flyingan aircraft � Wind speeds in aviation areusually given in knots.aviation gasolineaviation gasoline /�evieʃ(ə)n�$�səli�n/ noun fuel used in piston-engined aircraft. Abbreviation AVGASaviation lawaviation law /�evi|�eʃ(ə)n �lɔ�/ nounthe laws relating to flyingaviation routine weather reportaviation routine weather report/�evieʃ(ə)n �ru�ti�n �weθə r |�pɔ�t/noun a weather report issued regularlyat intervals of an hour or half an hourdescribing weather conditions at an air-port. Abbreviation METARaviatoraviator /�evietə/ noun a person whoflies aircraftavionicsavionics /�evi |�ɒnks/ noun elec-tronic communication, navigation, andflight-control equipment of an aircraft �The trainee engineer is doing an avion-ics course. Full form aviation elec-tronicsavoidavoid /ə|�vɔd/ verb 1. to preventsomething from happening � She justmanaged to avoid an accident. 2. tokeep away from something � Avoid fly-ing close to any person or vessel. �

Cumulonimbus clouds and thunder-storms should be avoided by as great adistance as possible.avoidanceavoidance /ə |�vɔd(ə)ns/ noun an actof avoiding something � avoidance ofthunderstorms is recommended it isrecommended to keep away from thun-derstormsawaitawait /ə |�wet/ verb to wait for � Awaitinstructions from the flight deck.awareaware /ə |�weə/ adjective knowing andbeing conscious of something � The

pilot should be aware of the positions ofall other aircraft in the circuit.awareness

awareness /ə |�weənəs/ noun thestate of being aware or conscious ofsomething � safety awareness the stateof being familiar with and prepared forany situation in which safety is impor-tantAWRAWR abbreviation airborne weatherradaraxial

axial /��ksiəl/ adjective referring to anaxisaxial flow compressoraxial flow compressor /��ksiəlfləυ kəm |�presə/ noun a compressor inwhich the flow of air is along the longi-tudinal axis of the engine � In spite ofthe adoption of the axial flow type com-pressor, some engine retain the centrif-ugal type.axisaxis /��kss/ noun 1. an imaginaryline around which a body rotates � TheEarth rotates around its own axis. � Anaircraft moves around three axes – ver-tical, longitudinal and lateral. � pitch,roll, yaw 2. a horizontal or vertical scaleon a graph, often referred to as the Xaxis, the horizontal axis, and the Y axis,the vertical axis � The plot shows theeffect of airspeed on lift with airspeedshown on the horizontal axis and lift onthe vertical axis. (NOTE: The plural formis axes.)axle

axle /��ksəl/ noun a shaft on which awheel is mounted � Unequal tyre-pres-sures, where two wheels are mounted onthe same axle, will result in one tyrecarrying a greater share of the loadthan the other. (NOTE: The wheel eitherturns round the axle or is fixed to theaxle.)azimuthazimuth /��zməθ/ noun the horizon-tal angle or direction of a compass bear-ing � Where precision approach radaris installed, the controller can informthe pilot if they depart from either theextended centre-line in azimuth orheight or both.


Bback

back /b�k/ verb (of the wind) tochange direction in an anticlockwisedirection. Opposite veerbackup

backup /�b�k�p/ adjective, noun asecond or third system, instrument orcomputer disk available to be used if thefirst one fails � The backup system orthe backup failed as well. � Backup gen-erators are driven by the engine.backward

backward /�b�kwəd/ adjectivedirected towards the back � a backwardmovementbackwards

backwards /�b�kwədz/ adverbtowards the back � Unlike most aircraft,the C130 can move backwards using itsown power. (NOTE: The US English isbackward.)backwash

backwash /�b�kwɒʃ/ noun a back-ward flow of air produced by an aircraftpropeller or jet enginebaffle

baffle /�b�f(ə)l/ noun a metal plate forpreventing the free movement of soundor liquids � Integral fuel tanks can bestrengthened by fitting baffle plates.baggage

baggage /�b�$d"/ noun luggage,cases and bags which you take with youwhen travelling � One passenger had ahuge amount of baggage. � She lost onepiece of baggage. (NOTE: The word lug-gage is also used in British English.) �baggage hall an area where arrivingpassengers pick up their baggage �carry-on baggage small bags of lim-ited size and weight that passengers areallowed to take with them into the cabinof an aircraftbaggage allowance

baggage allowance /�b�$d" ə |

�laυəns/ noun the weight of baggageeach air passenger is allowed to take

free � There is an accompanied bag-gage allowance of 18 kilos.baggage handlingbaggage handling /�b�$d"�h�ndlŋ/ noun the process by whichpassengers’ baggage is loaded onto anaircraft, or unloaded and moved to theairport terminalbalancebalance /�b�ləns/ noun 1. a state inwhich weight, force or importance areevenly distributed � The propelling noz-zle size is extremely important and mustbe designed to obtain the correct bal-ance of pressure, temperature andthrust. 2. the act of staying steady �

verb 1. to be opposite and equal inweight, force or importance to some-thing else � The pressure exerted by theweight of the atmosphere above thelevel of the bowl balances a column ofmercury in the tube. 2. to stay steady,especially when resting on the centre ofgravity

‘…balance refers to the location of thecentre of gravity along the longitudinalaxis of the aeroplane’ [Civil AviationAuthority, General Aviation Safety SenseLeaflet]

ballball /bɔ�l/ noun in an inclinometer, theround object which indicates if a turn iscoordinated � to step on the ball to cor-rect a skid or a slip by putting pressureon the rudder on the side to which theball in an inclinometer has moved dur-ing a turn. If the ball has moved to theleft, the turn can be corrected by puttingpressure on the left rudder, and viceversa.balloonballoon /bə |�lu�n/ noun a large baginflatable with hot air or gas to providelift, but without power � Balloons aresent into the upper atmosphere to col-


BALPA 30

lect information useful to meteorolo-gists.BALPABALPA /�b�lpə/ abbreviation BritishAir Line Pilots Associationbandband /b�nd/ noun 1. a narrow strip �

A jet stream is a narrow band of high-altitude strong winds. 2. a range ofnumbers or frequencies between twolimits within a radio systembandwidthbandwidth /�b�ndwdθ/ noun thewidth of a band of radio frequencies �

The sharp setting means the bandwidthis reduced to one kilohertz to minimisenoise or interference.bankbank /b�ŋk/ verb (of an aircraft) torotate or roll around its longitudinalaxis to a particular angle � Stresses areincreased when the aircraft banks, turnsor pulls out of a dive. � noun (of an air-craft) a rotating or rolling movementaround its longitudinal axis to a particu-lar angle � An attitude indicator givesthe pilot pitch and bank information.barbar /bɑ�/ noun 1. a long, straight, rigidpiece of metal � The part is made froma solid bar of aluminium. 2. (in meteor-ology) a unit of atmospheric pressureequal to 1,000 millibars. � millibarbarographbarograph /�b�rə$rɑ�f/ noun aninstrument for measuring and recordingatmospheric pressure � The most com-mon type of barograph is that which uti-lises an aneroid capsule mechanicallyconnected to a pen.barometerbarometer /bə|�rɒmtə/ noun aninstrument for measuring the atmos-pheric pressurebarometricbarometric /b�rə|�metrk/ adjectivereferring to a barometer � barometricpressure atmospheric pressure as indi-cated by a barometerbarometric tendencybarometric tendency/�b�rəmetrk �tendənsi/ noun theamount of change in pressure withincrease in altitudebarrel rollbarrel roll /�b�r(ə)l rəυl/ noun amanoeuvre in which an aircraft turnscompletely over sideways while flyingalongbarrierbarrier /�b�riə/ noun 1. somethingsuch as a wall that prevents the move-ment of something else � Elevation ofthe ground over which the aircraft flies

can be a dangerous barrier to flight. 2.something that prevents a person frommaking progress � His medical prob-lems were a barrier to his successfulcompletion of the course.basebase /bes/ noun the bottom part orlowest part � verb to develop or developsomething from something else � Theoperation of the auxiliary power unit isbased on the gas turbine engine. � Theprinciple of vapour cycle cooling isbased upon the ability of a refrigerantto absorb heat.base legbase leg /�bes le$/ noun the part ofthe airfield traffic circuit flown atapproximately 90° to the direction oflanding, followed by the final approach.� legbasicbasic /�besk/ adjective referring tothe most important but often simplestpart of something, from which every-thing else is derived � This chapter pro-vides a basic understanding from whichthe study of meteorology can develop. �basic principle a central or fundamen-tal idea or theorybasic area navigationbasic area navigation /�besk�eəriə �n�v|�$eʃ(ə)n/ noun a standardof performance for navigation thatrequires an aircraft to remain within 5nautical miles of the centreline of itscourse for 95% of the timebasisbasis /�bess/ noun the central andmost important part of something fromwhich everything else is derived � Thebasis of air navigation is the triangle ofvelocities. (NOTE: The plural form isbases.)batbat /b�t/ noun an object shaped like atable-tennis bat used by a person on theground to guide an aircraft when it istaxiing or parkingbatsmanbatsman /�b�tsmən/ noun some-body who uses a pair of bats to guide anaircraft when it is taxiing or parkingbatterybattery /�b�t(ə)ri/ noun a chemicaldevice that produces electrical current �This piece of equipment is powered by 2batteries. � chargerbaybay /be/ noun 1. a space or area in thestructure of an aeroplane where equip-ment can be located � To avoid damageto the wheel bay, the nose wheel must be


31 beware

aligned in a fore and aft direction dur-ing retraction. 2. a part of the coast thatcurves inwards � the Bay of Bengalbayonet fitting

bayonet fitting /�beənt �ftŋ/noun a means of attaching something tosomething, in which an object with twoside pins is inserted into a L-shaped slotin another object on some light-bulbs �

Magnetic chip detectors are of the bay-onet type fitting and can be removedand replaced very quickly.beacon

beacon /�bi�kən/ noun a light or radiosignal for navigational purposes � If theaircraft turns towards the beacon, sig-nal strength will increase.beam

beam /bi�m/ noun 1. a long thickmetal bar used as a support � A beam isdesigned with a breaking load of 12tons but when a three ton load isapplied repeatedly, the beam may fail.2. a shaft of light or radiation travellingin one direction, as from a car’s head-lights � The electron gun produces astream of fast-moving electrons andfocuses them into a narrow beam.beam sharpening

beam sharpening /�bi�m�ʃɑ�pənŋ/ noun the process of makinga radio or light beam narrower � Anysystem employing beam sharpening isvulnerable to side lobe generation atthe transmitter.bear

bear /beə/ verb 1. to carry or to hold �The undercarriage has to bear theweight of the aircraft on the ground. �rain-bearing cloud a cloud carryingmoisture which can fall as rain 2. � tobear something in mind to keep inmind � it should be borne in mind itshould be remembered � bearing inmind considering � Bearing in mindthat she hadn’t flown for three weeks,the student pilot’s landings were verygood. 3. to be able to deal with some-thing without becoming distressed orannoyed � He can’t bear the noise.(NOTE: bearing – bore – borne) � hecan’t bear the heat the heat is toomuch for himbearing

bearing /�beərŋ/ noun 1. the angle,measured in a clockwise direction, of adistant point, relative to a referencedirection � To plot a position line fromthe non-directional radio beacon, it is

first necessary to convert the relativebearing to a true bearing and then cal-culate the reciprocal. 2. a device con-taining steel balls or needles whichallows free rotation of one componentaround anotherBeaufort scaleBeaufort scale /�bəυfət skel/ nounscale from 1–12 used to refer to thestrength of wind � Wind speeds can beestimated by using the Beaufort scale ofwind force.belly flopbelly flop /�beli flɒp/ noun same asbelly landingbelly landingbelly landing /�beli �l�ndŋ/ nounan emergency landing of an aircraftwhen the wheels have not come downbeltbelt /belt/ noun 1. a long, relativelynarrow area � high-pressure belt longnarrow area of high pressure � precipi-tation belt a long narrow area of rain,snow or hail � rain belt long narrowarea where rain falls � The cirrus cloudcan be 900 miles ahead of the surfacefront with a rain belt as wide as 200miles. 2. a loop of strong material con-necting two pulleys or wheels, one driv-ing the otherbelt-drivenbelt-driven /�belt �drv(ə)n/ adjec-tive (of a wheel) moved by a belt linkedto another wheel which, in turn, ismoved by a motor or an engine � Air-craft generators are belt-driven orshaft-driven.belt-driven generatorbelt-driven generator /�belt�drv(ə)n �d"enəretə/ noun a genera-tor whose pulley is turned by a beltattached to an engine-driven pulleybendbend /bend/ noun a curve � verb tocurve from a straight shape (NOTE:bending – bent) � to bend down-wards to curve down from a horizontalposition � to bend upwards to curve upfrom a horizontal position � The wingssupport the weight of the aircraft andthey bend upwards in flight.bending loadbending load /�bendŋ ləυd/ noun aload that causes a structure to bendBernoulli’s principleBernoulli’s principle /b%� |�nu�li�z�prnsp(ə)l/ noun � liftbewarebeware /b|�weə/ verb to be careful orto watch out for � Beware of carburettoricing. � Beware of other aircraft in thecircuit.


beyond 32beyondbeyond /b|�jɒnd/ preposition furtheraway than � The radio horizon extendsbeyond the visible horizon. � it isbeyond his understanding he cannotunderstand it at all, it is too difficult forhim to understandbi-bi- /ba/ prefix 1. two 2. twicebiannualbiannual /ba |��njuəl/ adjective hap-pening two times a year � biannualinspection an inspection done twiceevery yearbillbill /bl/ noun US same as note noun 4bimetallicbimetallic /�bame |�t�lk/ adjectivemade of two metalsbimetallic stripbimetallic strip /�bamet�lk�strp/ noun a strip made of two sepa-rate metals with different rates ofexpansion, joined together side by sideso that when the strip is heated, it bendsand makes, or breaks, electrical contact� Circuit breakers use a bimetallic stripas the sensing element.binarybinary /�banəri/ adjective referring toa number system used in computers thatonly uses the digits 0 and 1 � Logicgates work with binary data. � Comput-ers only process binary information.biplanebiplane /�baplen/, bi-plane noun anold aeroplane design with two pairs ofwings, one above the other � Most of theaircraft used in the 1914–18 war werebiplanes.bird strikebird strike /�b%�d strak/ noun a col-lision between a bird or birds and an air-craft that is flyingblack boxblack box /�bl�k �bɒks/ noun sameas flight data recorder (NOTE: It isoften called the black box, although itis not black.)bladeblade /bled/ noun a flattened part of apropeller or rotor � blade tip the end ofthe blade furthest from the centre ofrotation � turbine blade a flat part in aturbine, which has an aerodynamiceffect on the airblade angleblade angle /�bled ��ŋ$(ə)l/ nounthe angle between the blade axis and theaxis of rotation � With a variable pitchpropeller, the blade angle may bechanged in flight.blade slipblade slip /�bled slp/ noun a loss ofpropulsive power from a propeller

caused by the difference between geo-metric and effective pitchblade twistblade twist /�bled twst/ noun 1. areduction in propeller blade angle fromroot to tip 2. the unwanted variation inpropeller blade pitch from root to tipcaused by aerodynamic loadsblankblank /bl�ŋk/ adjective 1. with noth-ing written, printed or drawn on it � ablank sheet of paper � a blank form aform without the details filled in 2. (of aTV, computer or video screen) withnothing appearing on it � When hereturned to his computer, the screen wasblank.bleed airbleed air /�bli�d eə/ noun compressedair from the engine compressor used forcabin pressurisation or to drive otherservices � Bleed air from the rightengine can power items normally pow-ered by the left engine.bleed screwbleed screw /�bli�d skru�/ noun asmall screw in highest point of ahydraulic system to allow for theremoval of air or vapourblind transmissionblind transmission /�bland tr�nz |

�mʃ(ə)n/ noun a transmission from onestation to another in a situation wheretwo-way communication cannot beestablished but where it is believed thatthe called station is able to receive thetransmissionblockblock /blɒk/ noun a large mass ofsomething � verb 1. to prevent some-thing such as a fluid from passing freelythrough a pipe or channel � At high alti-tude, any water condensing out of thefuel could freeze and block the filters. 2.to prevent a course of action � The gov-ernment blocked attempts to prevent thebuilding of the new airport.blockageblockage /�blɒkd"/ noun 1. a collec-tion of something blocking a pipe, nar-row channel, filter, etc. � Ice crystalsmay form to cause a blockage of the fuelfilter. 2. the state of being blocked � Theblockage was caused by ice.blowblow /bləυ/ noun 1. an impact � a blowon the head 2. a disappointment � Thenews of her failure in the examinationwas a severe blow. � verb 1. (of the windor air) to move � The sea breeze mayblow almost parallel to the coast. 2. (of


33 boot

a fuse) to break, as it should, when thecircuit is overloaded (NOTE: blowing –blew – blown)blow-backblow-back /�bləυ b�k/ noun a sud-den movement of fluid in the oppositedirection to the general flow � A suddenrelease of pressure may cause a blow-back.blowerblower /�bləυə/ noun a device forblowing air � Air for combustion isobtained from a blower.boardboard /bɔ�d/ noun 1. a flat, square orrectangular piece of wood or othermaterial 2. � on board on an aircraft �

The flight plan records the callsign andthe number of people on board. � verbto get on to an aircraft � In an emer-gency, many passengers only rememberthe entrance by which they boarded theaircraft.boarding gateboarding gate /�bɔ�dŋ $et/ nounthe door through which passengersleave the terminal building to get on toan aircraft � Boarding gates 1 – 10 areon the left.boarding passboarding pass /�bɔ�dŋ pɑ�s/ nouna temporary pass, issued at the check-indesk, which allows the holder to boardthe aircraft � Boarding passes must beshown at the gate. (NOTE: The pluralform is boarding passes.)boarding stepsboarding steps /�bɔ�dŋ steps/ plu-ral noun stairs used by passengers andcrew to get on board an aircraft � Pas-sengers had to wait in the aircraft for 15minutes before the boarding steps wereput in position.boarding timeboarding time /�bɔ�dŋ tam/ nounthe time when passengers are due toboard the aircraft � Boarding time is at13.30 hrs.bodybody /�bɒdi/ noun 1. the whole of aperson or an animal 2. the main part ofa person, but not the arms or legs 3. themain part of an aeroplane, system, text,etc. � The body of an aircraft is alsocalled the ‘airframe’. � A flow-controlvalve consists of a body and a floatingvalve. 4. a large mass of liquid or gas �body of air a large quantity of airbehaving in a particular way 5. anobject � Acceleration is the rate ofchange of velocity of a body.

boil

boil /bɔl/ verb to heat a liquid until itreaches a temperature at which itchanges into gas � Water boils at100°C. � boiling point the temperatureat which a liquid changes into gas � Theboiling point of water is 100°C.bolt

bolt /bəυlt/ noun 1. a metal rod with ahead, which screws into a nut � The twohalves of the wheel are held together bybolts. 2. � bolt of lightning one electri-cal discharge of lightning � verb toattach with a bolt � Aircraft wheels areconstructed in two halves which arebolted together.bond

bond /bɒnd/ noun the power thatholds surfaces together, when they arejoined using heat, cold, chemicals orglue � The de-icing boot breaks thebond between the ice and the outer skin.� verb to join surfaces together nor-mally using heat, cold, chemicals orglue � The skin is bonded to the internalmembers by the redux process.boom

boom /bu�m/ noun in some aircraft, aspar that connects the tail to the fuse-lageboost

boost /bu�st/ noun an increase orimprovement � The improvement in acountry’s economy often gives a boostto the airline industry. � verb 1. to makeor to help something increase � An oilpump boosts engine oil pressure. 2. toincrease � The instructor’s commentsboosted the student pilot’s confidence.booster

booster /�bu�stə/ noun a devicewhich increases the force or amount ofsomethingbooster pump

booster pump /�bu�stə p�mp/ nouna centrifugal pump often positioned atthe lowest point of a liquid fuel tank toensure positive pressure in the supplylines to the engine � Fuel is fed througha filter and a booster pump. � The pur-pose of the booster pump is to preventfuel aeration.boot

boot /bu�t/ noun one of a set of flat,flexible tubes bonded to the leadingedge or wings and other surfaces which,when pressurised with fluid, break upice � The boots on the leading edge ofthe wings were damaged by hail.


bottleneck 34bottleneckbottleneck /�bɒt(ə)lnek/ noun abuildup of air traffic causing delays intaking off or landingboundbound /baυnd/ adjective � bound foron the way to � an aircraft bound forParis � the Copenhagen-bound flightthe flight on the way to Copenhagen �outward bound leaving home, espe-cially for another countryboundaryboundary /�baυnd(ə)ri/ noun a phys-ical or imaginary limit between twoareas � The boundary between two airmasses is called the frontal surface.boundary layerboundary layer /�baυnd(ə)ri �leə/noun the layer of fluid next to the sur-face over which it is flowing and,because of friction, travelling moreslowly than layers further from the sur-facebowserbowser /�baυzə/ noun a mobile fueltank for refuelling aircraft � It is impor-tant to prevent the possibility of an elec-tric spark by earthing the aircraft andthe bowser.Boyle’s LawBoyle’s Law /�bɔlz lɔ�/ noun a sci-entific principle that states that the vol-ume of a given mass of gas, whose tem-perature is maintained constant, isinversely proportional to the gas pres-surebracebrace /bres/ verb 1. to strengthen aconstruction using cross-membersand/or wires � Early aircraft were of thebraced type of construction. 2. to take aprotective body position in preparationfor a crash landing � The cabin-crewwill repeat the ‘brace’ order and bracethemselves. � to brace yourself toquickly prepare yourself mentally andphysically for what is shortly to happenbrace positionbrace position /�bres pə |�zʃ(ə)n/noun the position that a person is rec-ommended to adopt before impact in acrash, protecting the head with the armsand bringing the legs up underneath thechestbracketbracket /�br�kt/ noun 1. a metalsupport, often triangular or L-shaped �component bracket a metal device toattach and support a component 2. arange of frequencies within a band ofradio frequencies � Terminal VOR is inthe frequency bracket 108–112 MHz. 3.

� round brackets the printing symbol () used to separate words in a sentence,or within a text � square brackets theprinting symbol [ ] used to enclosesome types of textbrakebrake /brek/ noun a device for stop-ping a vehicle or a machine � parkingbrake a brake used to prevent the air-craft moving after it has come to a stop� verb to slow down or to stop by press-ing the brakes � He had to brake hardafter landing in order to turn off at thecorrect taxiway. (NOTE: braking –braked)brake drum

brake drum /�brek dr�m/ noun around hollow part of the brake mecha-nism, which is attached to the wheeland against which the brake shoes rub,thus preventing the wheel from turningbrakingbraking /�brekŋ/ noun the act ofputting on the brakes to slow down or tostop � adjective slowing down � thebraking effect of drag � actionbreaking loadbreaking load /�brekŋ ləυd/ nouna load capable of being supportedbefore a structure breaksbreatherbreather /�bri�ðə/ noun 1. a pipe con-necting the crankshaft to the atmos-phere to prevent build-up of crankcasepressure 2. a short rest (informal ) � totake a breather to have a short break,to relax before starting againbreezebreeze /bri�z/ noun a gentle windespecially near the coast � There’s nowind, not even a breeze. � land breezea light wind which blows from the landtowards the sea � Land and sea breezesoccur in coastal areas. � sea breeze agentle wind which blows from the seatowards the land � The strength of thesea breeze decreases with height.briefbrief /bri�f/ adjective short � briefvisit a visit that lasts only short time �brief letter a letter containing only afew words � noun general instructionsto enable somebody to perform theirduties � The inspector’s brief is to findout as much as possible about thecauses of accidents. � verb to give basicinformation to somebody � Before take-off, cabin crew must brief passengers onthe location and use of emergency exitsand life jackets.


35 bulkheadbriefing

briefing /�bri�fŋ/ noun a short meet-ing to enable instructions and basicinformation to be givenBritish Isles

British Isles /�brtʃ �alz/ pluralnoun the islands which make up GreatBritain and Ireland � The climate of theBritish Isles is affected by the AtlanticOcean.British thermal unitBritish thermal unit /�brtʃ�θ%�m(ə)l/ noun the amount of heatneeded to raise the temperature of onepound of water by one degree Fahren-heit. Abbreviation Btubrittle

brittle /�brt(ə)l/ adjective having atendency to break easily, like thin glass� Absorption of oxygen and nitrogenfrom the air at temperatures above1,000° F makes titanium brittle.BRNAV

BRNAV abbreviation basic area navi-gationbroad

broad /brɔ�d/ adjective 1. very wide �a broad river 2. wide or general � Threebroad categories of aircraft are consid-ered – rotary wing aircraft, light single-engine aircraft and twin-engine air-craft. Opposite narrowbroadcast

broadcast /�brɔ�dkɑ�st/ verb totransmit, often to a large number of peo-ple, a radio signal or message whichrequires no answer � The cabin crewcan use the public address system tobroadcast messages to passengers only.(NOTE: broadcasting – broadcast) �

noun a transmission of informationrelating to air navigation that is notaddressed to a specific station or sta-tionsbroadly

broadly /�brɔ�dli/ adverb widely orgenerally � broadly speaking gener-ally speakingbrush

brush /br�ʃ/ noun 1. a tool that haslengths of hair or wire fixed into a han-dle and is mainly used for painting orcleaning 2. a small, replaceable block ofcarbon which rubs against the surfaceof a commutator in a generator or elec-tric motor � At high altitude, the airbecomes drier and this causes a greatlyincreased rate of wear on the brushes.buckle

buckle /�b�k(ə)l/ noun a metal part ofa belt used for joining the two endstogether � verb to bend out of shape

because of heat or force � Overheatingwill make the battery plates buckle.buffet

buffet /�b�ft/ noun a shaking move-ment of the aircraft caused by the break-down of the airflow over the upper sur-face of the wing � Large aircraft use astick shaker to supplement the naturalstall warning of buffet. � verb to pusharound with great force, as by water orwind � The storm buffeted the coast. �

The aircraft was buffeted by strongcrosswinds as it made its final approachto land.

COMMENT: Buffet is a warning to thepilot that the smooth airflow over thewing is breaking down and that heshould take corrective action toprevent a stall.

buffeting

buffeting /�b�f(ə)tŋ/ noun an irregu-lar shaking of a part or the whole of anaircraft during flight, usually caused bystrong windsbuffet speed

buffet speed /�b�ft spi�d/ noun thespeed at which buffet is first noticedbug

bug /b�$/ noun a fault in computersoftware which causes the program tooperate incorrectlybuild up

build up /�bld ��p/ verb to form byaccumulation � In icing conditions, icebuilds up on the leading edges. � built-up (NOTE: building up – built up)build-up

build-up /�bld �p/ noun a gradualaccumulation � a build-up of staticelectricitybuilt-up

built-up /�blt ��p/ adjective � built-up area an area which is full of houses,shops, offices, and other buildings, andwith very little open spacebulb

bulb /b�lb/ noun 1. a glass ball insidea lamp that gives electric light � If alamp does not work, the bulb may needreplacing. 2. something shaped like alamp bulb � The most common type ofhygrometer is the wet and dry bulb ther-mometer arrangement.bulkhead

bulkhead /�b�lkhed/ noun a dividingpartition across the structure of thefuselage separating one compartmentfrom another for reasons of safety orstrength � A fireproof bulkhead is pro-vided to separate the cool area of theengine from the hot area.


bulletin 36bulletinbulletin /�bυltn/ noun a short reportor information on a situation � newsbulletin � weather bulletin � A terminalaerodrome forecast bulletin may consistof forecasts for one or more aero-dromes.BUMFBUMF � mnemonicburbleburble /�b%�b(ə)l/ noun a break in theflow of air around an aircraft’s wing,which leads to turbulenceburstburst /b%�st/ noun 1. a minor explo-sion caused by increased pressure � Therisk of tyre burst through overheating isincreased by hard application of thebrakes. 2. a very short period of activityfollowed by no activity � The groundinstallation transmits a code in twoshort bursts. � burst of energy a veryshort period of energy � verb to explodebecause of increased pressure or punc-ture � Metal debris on the runway maycause a tyre to burst. (NOTE: bursting –burst)busbarbusbar /�b�sbɑ�/ noun an electricalconductor used to carry a particular

power supply to various pieces ofequipment � Complex busbars are thickmetal strips or rods to which input andoutput connections are made.button

button /�b�t(ə)n/ noun a little rounddisc which you push to operate some-thing, e.g. to ring a bellBuys Ballot’s Law

Buys Ballot’s Law /�baz �b�ləts�lɔ�/ noun a rule for identifying lowpressure areas, based on the Corioliseffect

COMMENT: In the northernhemisphere, if the wind is blowing frombehind you, the low pressure area is tothe left, while in the southernhemisphere it is to the right.

buzz

buzz /b�z/ verb to fly low in an aircraftover people or buildings, or to fly acrossthe path of other aircraftbypass

bypass /�bapɑ�s/ noun 1. an alterna-tive pipe, channel, etc. � A turbinebypass in the form of an alternativeexhaust duct is fitted with a valve. 2.same as shunt


CCC symbol 1. Celsius 2. centigradeCAACAA abbreviation Civil AviationAuthoritycabincabin /�k�bn/ noun a passenger com-partment in an aircraft � Air enters atthe front of the cabin and leaves at therear.cabin attendantcabin attendant /�k�bn ə |

�tendənt/ noun member of the flightcrew who looks after passengers, servesfood, etc. � If you need something, pressthe call button and a cabin attendantwill respond within a few minutes. Alsocalled flight attendantcabin compressor and blower systemcabin compressor and blowersystem /�k�bn kəm|�presə ən�bləυə �sstəm/ noun part of the airconditioning system for the cabincabin crewcabin crew /�k�bn kru�/ noun air-line staff who are in direct contact withthe passengers and whose in-flightresponsibilities include: ensuring cor-rect seating arrangements, serving foodand attending to the general well-beingof passengers, etc.cabin environmentcabin environment noun the condi-tions inside the aircraft cabin, includingthe temperature, the space, the colourscheme, the seating arrangements, etc.cabin pressurecabin pressure /�k�bn �preʃə/noun the pressure of air inside the cabinwhich allows people to breathe nor-mally at high altitudescabin pressurisationcabin pressurisation /�k�bn�preʃəra |�zeʃ(ə)n/ noun the mainte-nance of an acceptable atmosphericpressure in an aircraft while flying athigh altitude � At 35,000 ft (feet) pas-sengers can breathe freely because ofcabin pressurisation.

cablecable /�keb(ə)l/ noun 1. thick metalwire � control cables thick metal wirelinking the pilot’s cockpit controls tocontrol surfaces such as the elevatorsand ailerons 2. a thick metal wire usedfor electrical connections � Earthreturn is by cable to the negative pole ofthe battery.cabotagecabotage /�k�bətɑ�"/ noun the rightof a country to operate internal air traf-fic with its own airlines and not those ofother countriescalculatecalculate /�k�lkjυlet/ verb to findout an answer to a problem by workingwith numbers � The total flight fuel canbe calculated by multiplying the time ofthe flight by kilograms of fuel per hour.calculationcalculation /�k�lkjυ |�leʃ(ə)n/ nounan act of finding out an answer to aproblem by working with numberscalculation of fuel requiredcalculation of fuel required/�k�lkjυleʃ(ə)n əv �fju�əl r |�kwaəd/noun an arithmetic estimation of fuelneeded by using time, distance and fuel-consumption factorscalculatorcalculator /�k�lkjυletə/ noun anelectronic machine for making calcula-tions � Students are not allowed to usecalculators in the examination.calibratecalibrate /�k�lbret/ verb to adjustthe scale or graduations on a measuringinstrument or gauge � The internationalstandard atmosphere is used to cali-brate pressure altimeters.calibrated airspeedcalibrated airspeed /�k�lbretd�eəspi�d/ noun indicated airspeed cor-rected for instrumentation and installa-tion errors. Abbreviation CAScalibrationcalibration /�k�l|�breʃ(ə)n/ nounthe adjusting of the scale or graduations


call button 38

on a measuring instrument or gauge �

The international standard atmosphereis used for the calibration of instru-ments.call button

call button /�kɔ�l �b�t(ə)n/ noun abutton, often on the arm of a passengerseat, which can be pushed when youneed help from an attendantcallsign

callsign /�kɔ�lsan/ noun a series ofwords and/or letters and/or numbersused to identify an aircraft or station �

The aircraft’s callsign is ‘College 23’. �VOR stations transmit a two or threeletter aural Morse callsign.calorie

calorie /�k�ləri/ noun the amount ofheat required to raise the temperature of1 gram of water by 1°C, equal to 4.186joules � After 2 calories have beenreleased the temperature will have risen2 degrees i.e. to 0°C, and so the freezingprocess ceases temporarily. Abbrevia-tion calcalorific

calorific /�k�lə |�rfk/ adjective refer-ring to calories � calorific value theheat produced by the complete burningof a given amount of fuel � The calorificvalue of a fuel is an expression of theheat or energy content released duringcombustion.cam

cam /k�m/ noun an oval or egg-shaped wheel which, when rotating,converts circular motion into recipro-cating motion � In a piston engine, theshape of each cam is designed to givethe correct amount of opening to thevalve.CAMFAX

CAMFAX /�k�mf�ks/ noun the civilaviation meteorological facsimile net-workcamplate

camplate /�k�mplet/ noun a rotat-ing or non-rotating plate with cams on it� The fuel pump consists of a rotorassembly fitted with several plungers,the ends of which bear onto a non-rotat-ing camplate.camshaft

camshaft /�k�mʃɑ�ft/ noun a rotat-ing shaft carrying cams, which opensand closes valves in a piston engine � Asthe camshaft rotates, the cam will trans-mit a lifting force.canard

canard /�k�nɑ�d/ noun a projectionsimilar to a small wing fitted close to

the nose of an aircraft and designed toincrease its horizontal stabilitycandelacandela /k�n |�di�lə/ noun the SI unitof brightness of a light � The red andgreen wing tip navigation lights must beat least 5 candela. (NOTE: It is usuallywritten cd with figures.)candle powercandle power /�k�nd(ə)l �paυə/noun a unit to measure the brightness ofa light � Estimation of visibility isachieved by noting the distances atwhich lights of a known candle powercan be observed.canopycanopy /�k�nəpi/ noun 1. a transpar-ent cover, typically on some fighters,light aircraft and gliders, designed toslide backwards and forwards or hingeupwards to allow pilots to enter or leavean aircraft 2. a covering to protect peo-ple in a life raft � The canopy should beerected to provide protection from theweather.cantilevercantilever /�k�ntli�və/ noun a beamfixed and supported at one end only �

The mainplanes or wings are of canti-lever design.capcap /k�p/ noun a top or lid � theexhaust valve capCAPCAP abbreviation Civil Aviation Pub-licationcapabilitycapability /�kepə |�blti/ noun thecapacity or ability to do something �the flare has a day and night capabil-ity the flare is effective in daylight andin the dark

‘France has a large capability in the areasof commercial aviation training andsimulation’ [Civil Aviation Training]

capablecapable /�kepəb(ə)l/ adjective com-petent, having an ability � Aircraft usedin aerobatics must be capable of with-standing the extra loads imposed on theairframe by the manoeuvres. � In mostmodern multi-engine jet transport air-craft, each fuel tank is capable of feed-ing any engine. � a capable person aperson who works wellcapacitancecapacitance /kə|�p�stəns/ noun theability of a system of conductors andinsulators to store an electrical chargewhen there is a positive dischargebetween the conductors � If the supplyfrequency is low, the voltage has more


39 cardioid

time to build up a larger charge, orcapacitance. (NOTE: Capacitance ismeasured in farads and can either be afixed amount or variable amount.)capacitivecapacitive /kə |�p�stv/ adjectivereferring to the ability of a system ofconductors and insulators to store anelectrical charge � Overspeed is usuallya fault in the constant speed drive unitwhich causes the generator to over-speed and damage the capacitive loadson the aircraft.capacitorcapacitor /kə |�p�stə/ noun a systemof conductors and insulators whichstore electrical charge (NOTE: A capaci-tor is used in a circuit to store energy fora short while.)capacitycapacity /kə |�p�sti/ noun 1. the abil-ity to do something easily � Energy isthe capacity for performing work. 2. theamount of something which a containercan hold � Each cylinder has a capacityof 0.5 litres. � battery capacity theamount of electrical energy a batterycan store and deliver expressed inampere hours 3. the ability of an ATCsystem, in a given area, to provide anormal service, expressed in numbersof aircraft

‘…a 500 to 600 seat ultra-high capacitytype aircraft is now being studied byAirbus Industrie and Boeing’ [FlightInternational 1–7 May 1996]

capillarycapillary /kə |�pləri/ noun a very fineor narrow tubecapillary actioncapillary action /kə |�pləri ��kʃən/,capillary flow /kə |�pləri fləυ/ noun theaction by which a liquid rises up a nar-row tubecapsulecapsule /�k�psju�l/ noun a smallclosed containercaptaincaptain /�k�ptn/ noun the person incharge of an aircraft � The captainasked all passengers to remain seateduntil the aircraft had come to a stop.captivecaptive /�k�ptv/ adjective not free tomovecaptive ballooncaptive balloon /�k�ptv bə|�lu�n/noun a balloon which, when in flight, isattached to the ground by a long cablecarboncarbon /�kɑ�bən/ noun 1. a non-metallic element, which is a componentof living matter and organic chemical

compounds and is found in variousforms, e.g. as diamonds or charcoal 2. ablack material with good electricalpropertiescarbon brush

carbon brush /�kɑ�bən br�ʃ/ noun asmall, replaceable, carbon block foundin electric motors, generators and alter-nators, which provides the passage ofelectric currentcarbon depositscarbon deposits /�kɑ�bən d|

�pɒztz/ plural noun residues of burntoil deposited in the combustion cham-ber, etc., in the course of the combus-tion process � Carbon deposits on aspark-plug electrode may cause misfir-ing.carbon dioxide

carbon dioxide /�kɑ�bən da|

�ɒksad/ noun a colourless, odourless,non-toxic gas found in the atmosphere,and also used in fire extinguishers andfizzy drinks � Carbon dioxide can besolidified at low temperature to producedry ice. Symbol CO2carbon fibrecarbon fibre /�kɑ�bən �fabə/ noun athin, light and very strong strand of purecarbon which can be combined withother materials to make them strongercarbon monoxide

carbon monoxide /�kɑ�bən mə|

�nɒksad/ noun a colourless but poi-sonous gas from incomplete combus-tion found in the exhausts of spark igni-tion engines. Symbol COcarburationcarburation /�kɑ�bju |�reʃ(ə)n/ nounthe process of mixing fuel with air in acarburettor � Carburation must ensurethat rapid and complete burning willtake place within the cylinder.carburettor

carburettor /�kɑ�bə |�retə/ noun adevice for mixing air with fuel in theright quantities before combustion �

Most carburettors are installed so thatthey are in a warm position.carburettor heatcarburettor heat /�kɑ�bə |�retə hi�t/noun a system for keeping the carburet-tor and associated components free oficecarburettor icingcarburettor icing /�kɑ�bəretə�asŋ/ noun a process by which, underparticular conditions, ice forms in theventuri tube of the carburettorcardioid

cardioid /�kɑ�diɔd/ adjective shapedlike a heart � The cardioid polar dia-


carousel 40

gram of the magnetic field around abar-magnet.carouselcarousel /�k�rə |�sel/ noun a rotatingplatform from where arriving passen-gers can pick up their baggage � Bag-gage from flight AC123 is on carouselNo 4.carriagecarriage /�k�rd"/ noun the act ofcarrying � Regulations require the car-riage of life-rafts when flying overwater.carriercarrier /�k�riə/ noun 1. a person ororganisation that carries people orgoods from one place to another � Indi-vidual carriers assign codes to aircraft.2. a frame or bag in which objects canbe carriedcarrier wavecarrier wave /�k�riə wev/ noun aradio signal that is transmitted continu-ously at a constant amplitude and fre-quency � Amplitude modulation hasonly one pair of usable sidebands eachat about one sixth of the signal strengthof the carrier.carrycarry /�k�ri/ verb to take somebody orsomething from one place to another �

The aircraft was carrying 120 passen-gers. (NOTE: carrying – carried)cartridgecartridge /�kɑ�trd"/ noun a remova-ble unit for an air filter � Cabin air fil-ters normally consist of a casing, hous-ing a replaceable filter cartridge.CASCAS abbreviation 1. calibrated air-speed 2. controlled airspacecasecase /kes/ noun 1. an outer covering,housing or jacket � Cooling air isdirected through passages in the enginecase to control engine case tempera-ture. 2. an example, situation or circum-stance � In some special cases, e.g. forlanding and take-off, wind directionsare measured from magnetic north.casingcasing /�kesŋ/ noun a cover thatencloses a piece of equipment, etc. �

Annular and outer air casing form atunnel around the spine of the engine.CATCAT /k�t/ abbreviation clear air turbu-lencecatastrophecatastrophe /kə |�t�strəfi/ noun avery bad event or accident, a disaster �

the recent air catastrophe off the NovaScotia coast. � Although the familywere not at home when it happened, the

crash which destroyed their house wasa catastrophe for them.catastrophiccatastrophic /�k�tə|�strɒfk/ adjec-tive terrible, disastrous � In a cata-strophic accident where many personsmay be disabled, those who show signsof life should be rescued first.categorisecategorise /�k�t$əraz/, catego-rize verb to put into groups, classes orcategories � Figure 2 categorises thetypes of wave by frequency band. � Air-craft can be categorised by weight,number of engines, role, etc.categorycategory /�k�t$(ə)ri/ noun an offi-cial class or group � Load factors varydepending on the category of aircraft.cathodecathode /�k�θəυd/ noun a negativeelectrode or terminal � The cathode is ametal cylinder fitted with an internalheater.cathode ray tubecathode ray tube /�k�θəυd �re�tju�b/ noun a high-vacuum tube inwhich cathode rays produce an imageon a screen such as a TV screen � Elec-tronic indicating systems show engineindications, systems monitoring andcrew alerting functions on one or morecathode ray tubes or liquid crystal dis-plays mounted in the instrument panel.Abbreviation CRTcausecause /kɔ�z/ noun something thatmakes something else happen, a reason� If the ammeter shows a high state ofcharge after start up, it is quite normaland no cause for alarm. � verb to makesomething happen � Air in the fuel linecan cause an engine to flame-out orstop.cautioncaution /�kɔ�ʃ(ə)n/ noun 1. advice ora warning to be careful � If a problemoccurs in the spoiler system, a mastercaution light illuminates. 2. care � Pro-ceed with caution.cavitationcavitation /�k�v |�teʃ(ə)n/ noun theformation of vapour-filled cavities orholes in liquids and gases, caused bylow pressure or high speed � Most res-ervoirs are pressurised to provide apositive fluid pressure at the pump inletand thus prevent cavitation and the for-mation of bubbles.cavitycavity /�k�vti/ noun a hole � De-icing fluid flows into the cavity in the


41 centrifuge

distributor panels before passingthrough the porous steel outer skin.CBCB abbreviation cumulonimbuscccc /�si� �si�/ abbreviation cubic centi-metrescdcd symbol candelaCDICDI abbreviation course deviation indi-catorceasecease /si�s/ verb to stop � If fuel, oxy-gen or heat is removed from the fire tri-angle, combustion will cease.ceilingceiling /�si�lŋ/ noun 1. the highestpoint 2. the greatest pressure height thatcan be reached � The aircraft has a ceil-ing of 50,000 ft.celestialcelestial /sə |�lestiəl/ adjective refer-ring to the sky � celestial navigationnavigation by using the stars in the skycellcell /sel/ noun 1. a system of positiveand negative plates for storage of elec-tricity that form a battery � A battery isa device which converts chemicalenergy into electrical energy and ismade up of a number of cells. 2. the cen-tral part of a thunder cloud � The lifecycle of the thunderstorm cell endswhen the downdraughts have spreadthroughout the cloud.CelsiusCelsius /�selsiəs/ noun a scale formeasuring temperature in which waterfreezes at 0° and boils at 100°. SymbolC. Compare Fahrenheitcentercenter /�sentə/ noun, verb US same ascentrecenterlinecenterline /�sentəlan/ noun USsame as centrelinecentigradecentigrade /�sent$red/ noun ascale for measuring temperature inwhich water freezes at 0° and boils at100°. Symbol C. Compare Fahrenheitcentimetrecentimetre /�sentmi�tə/ noun ameasure of length that is equal to onehundredth of a metre (NOTE: 2.54 cm =1 inch.)centralcentral /�sentrəl/ adjective located inthe centre or in the middle � The controlknob is moved from the central position.Central Flow Management Unit Central Flow Management Unit(Brussels) /�sentr(ə)l fləυ�m�nd"mənt �ju�nt �br�s(ə)lz/noun a central agency in Brussels that isresponsible for air traffic management

throughout the area controlled by theECACcentralise

centralise /�sentrəlaz/, centralizeverb to put into the centre or into themiddle position � The operating jackcentralises the control surface after theturn.Central Standard Time

Central Standard Time /�sentrəl�st�ndəd �tam/ noun the time zone ofthe east-central part of the USA andCanada, 6 hours behind GMTcentrecentre /�sentə/ noun 1. the middle �

The plane of the great circle passesthrough the centre of a sphere. � centreof a circle mid-point of a circle, point inthe middle of a circle 2. a main buildingor office � Area Forecasting Centre �

verb to move to a central position �

Centre the control column. (NOTE: cen-tred – centring; the US English is cen-tered – centering.)centre fix

centre fix /�sentə fks/ noun same asself-positioningcentrelinecentreline /�sentəlan/ noun apainted or imaginary line running alongthe centre of the runway (NOTE: It is alsowritten centre line; written centerlinein US English.)centre of gravity

centre of gravity /�sentə əv�$r�vti/ noun the point at which abody can be balanced � Distribution ofthe tanks and the fuel in the tanks isvital in maintaining the aircraft centreof gravity and trim. Abbreviation CG

COMMENT: If the centre of gravity isoutside the limits, the aircraft may bedifficult or impossible to control.

centrifugal

centrifugal /�sentr|�fju�$(ə)l, sen |

�trfjυ$(ə)l/ adjective moving awayfrom the centre � The blades must bestrong enough to carry the centrifugalloads due to rotation at high speed.centrifugal forcecentrifugal force /�sentrfju�$(ə)l�fɔ�s/ noun outward force caused byturning motioncentrifugecentrifuge /�sentrfju�d"/ noun adevice which uses centrifugal force toseparate or remove liquids � verb toseparate liquids by using centrifugalforce � The rotating vanes of thebreather centrifuge the oil from themist.


centripetal 42centripetalcentripetal /�sentr|�pi�t(ə)l, sen |

�trpt(ə)l/ adjective moving towardsthe centrecentripetal force

centripetal force /sen |�trpt(ə)l�fɔ�s/ noun inward, centre-seekingforce working in opposition to centrifu-gal force � The magnitude of the cen-tripetal force varies with the square ofthe wind speed. � In a turn, lift providesthe centripetal force.certaincertain /�s%�t(ə)n/ adjective 1. partic-ular, some � in certain areas � at cer-tain times � under certain circum-stances 2. sure � There are certain to behorizontal differences in the mean tem-perature of a layer. � to make certainto make sure � Make certain that theparking brake is on before doing enginerun-up checks.certificatecertificate noun /sə|�tfkət/ an offi-cial document which states that particu-lar facts are true � verb /sə|�tfket/ toaward or give a certificate � aircraftwhich are certificated for flight air-craft which have the necessary paper-work to be authorised to flycertificate of airworthinesscertificate of airworthiness /sə |

�tfkət əv �eəw%�ðnəs/ noun a docu-ment issued by an aviation authoritystating that an aircraft meets specificsafety and performance requirementsthat allow it to be used in service � Anauthorised person may require produc-tion of the Certificate of Airworthiness.Abbreviation C of Acertification

certification /sə |�tf|�keʃ(ə)n/ nounthe process of giving certificates � Theinferential method of ice detection isused on flight trials for certification ofaircraft.certify

certify /�s%�tfa/ verb to authorise orpermit the use of something � The air-craft is certified for aerobatic flight.CFICFI abbreviation chief flying instructorCFMUCFMU abbreviation Central FlowManagement UnitCFRP

CFRP abbreviation carbon fibre rein-forced plasticchalkchalk /tʃɔ�k/ noun a soft white lime-stone rock that may be used in powderform or as a shaped stick for writingwith � Oil, which is trapped in the

defects, is absorbed by the chalk thusindicating their positions.chamberchamber /�tʃembə/ noun a smallenclosed compartmentchandellechandelle /ʃ�n |�del/ noun a steepclimbing turn in which an aircraftalmost stalls as it uses momentum toincrease its rate of climbchannelchannel /�tʃ�n(ə)l/ noun a specialfrequency band for the transmission ofradio signals � The system operates onVHF communications between 118 and135.95 MHz giving 360 channels at 50kHz spacing.charactercharacter /�k�rktə/ noun 1. a qual-ity or set of qualities which make some-thing different and separate from some-thing else � The circulation of theatmosphere is zonal in character. 2. anindividual letter, number or symbolused in printing and writingcharacterise

characterise /�k�rktəraz/, char-acterize verb � to be characterised byto have qualities or features which makeit different and separate from otherthings � The stratosphere is character-ised by a temperature structure which issteady or increases with height.characteristiccharacteristic /�k�rktə|�rstk/adjective typical of a class or group ofthings � a characteristic feature a nor-mal feature of the thing in question �

noun a feature or quality making some-thing different or separate from some-thing else � Air masses have distinctcharacteristics which can be used toseparate them on a chart. � handlingcharacteristics features of an aircraftthat make it different from other aircraftwhen handling it � summer character-istics climatic conditions which are typ-ical of summertimechargecharge /tʃɑ�d"/ noun 1. an amount ofelectricity � Friction causes a charge ofstatic electricity. � The battery was soold, it would not take a charge. � a highlevel of charge a high amount of elec-tricity 2. money demanded or paid forthe providing of a service � overnightparking is free of charge it costs noth-ing to park overnight � verb 1. to passelectrical current through somethingand thereby make it electrically active �


43 circuit

An installed battery becomes fullycharged by the aircraft generator. �charged particles atmospheric parti-cles which have either a positive or neg-ative electrical charge 2. to take moneyfor a service � We do not charge forovernight parking.charger

charger /�tʃɑ�d"ə/ noun � batterycharger device for putting an electricalcharge into a battery. � turbochargerchart

chart /tʃɑ�t/ noun a map for naviga-tional purposes � significant weatherchart a weather chart with importantweather information marked on itchase plane

chase plane /�tʃes plen/ noun anaircraft whose role is to escort anotheraircraft or to photograph itcheck

check /tʃek/ noun an examination tomake certain that something is as itshould be � safety check � A check wasmade on the undercarriage and air-frame after the pilot reported a heavylanding. � run � verb to examine some-thing in order to find out if it is correct� It is the pilot’s responsibility to checkthat the aircraft is airworthy.

‘European Union (EU) airports may beempowered to carry out safety checks onforeign airlines’ [Flight International 1–7 May 1996]

check in

check in /�tʃek �n/ verb to register bygiving in your ticket, showing yourpassport and giving your baggage at anairline desk before a flight � Passengersshould check in two hours before depar-ture.check-in

check-in /�tʃek n/ noun an airlinedesk where passengers register before aflight � The check-in is on the first floor.� check-in time time at which passen-gers should check incheck-in counter

check-in counter /�tʃek n�kaυntə/, check-in desk noun counterwhere passengers check inchecklist

checklist /�tʃeklst/ noun a list ofitems, often in booklet form, to bechecked in a given sequence � Beforeevery flight, the pilot should performpre-flight checks using a checklist.chemical

chemical /�kemk(ə)l/ adjectivereferring to chemistry � a chemicalreaction � noun a substance used in or

made by a chemical process � a chemi-cal such as anti-ice for propellerschemistrychemistry /�kemstri/ noun 1. thescience of chemical substances andtheir reactions 2. the nature of some-thing � The basic chemistry of fire canbe illustrated by the three sides of a tri-angle representing fuel, oxygen andheat.chiefchief /tʃi�f/ adjective most important,main � the chief factors the mostimportant factorschief flying instructorchief flying instructor /�tʃi�f�flaŋ n|�str�ktə/ noun the senior rankof flying instructor. Abbreviation CFIchockchock /tʃɒk/ noun a wooden or metaldevice placed in front of the wheels of aparked aircraft to prevent it from mov-ing � The accident happened becausethe chocks had been removed before theengine was started.chokechoke /tʃəυk/ noun a valve in a carbu-rettor, which controls the amount of aircombining with fuel � verb 1. to block atube, etc., making a liquid unable tomove � a choked nozzle a blocked orpartly-blocked nozzle 2. to stop breath-ing because you have inhaled water orsmokechoke tubechoke tube /tʃəυk tju�b/ noun sameas venturi � Increase in rpm increasesthe speed of air passing through thechoke tube or venturi.chopperchopper /�tʃɒpə/ (informal ) nounsame as helicopter � verb to transportsomething or somebody by helicopter,or to travel by helicopterchordchord /kɔ�d/ noun the shortest dis-tance between the leading and trailingedges of an airfoilchutechute /ʃu�t/ noun same as parachute(informal)circlecircle /�s%�k(ə)l/ noun a line forming around shape, or a round shape formedby objects or people � They stood in acircle on the tarmac. � great circledirection an imaginary circle on thesurface of the Earth which lies in aplane passing through the centre of theEarthcircuitcircuit /�s%�kt/ noun 1. a completeroute around which an electrical currentcan flow 2. the pattern of take-off,


circuit board 44

climb-out, turn onto crosswind leg, turnonto downwind leg, turn onto base leg,turn onto final approach and landing �

When carrying out practice landings atan aerodrome, the pilot should keep asharp lookout for other aircraft in thecircuit.circuit board

circuit board /�s%�kt bɔ�d/ noun aninsulating board which holds compo-nents connected into an electrical cir-cuitcircuit-breaker

circuit-breaker /�s%�kt �brekə/noun a small protective device in thecircuit which blows or breaks before adangerous overload of current arisescircuitry

circuitry /�s%�ktri/ noun a system ofelectrical circuits � In an anti-skid brak-ing system, circuitry is employed whichcan detect individual wheel decelera-tion.circular

circular /�s%�kjυlə/ adjective shapedlike a circle � Anodes are circularplates with centre holes. � semi-circu-lar shaped like a half-circle � noun adocument distributed to a large numberof people � an aeronautical informationcircularcircular slide rule

circular slide rule /�s%�kjυlə �slad�ru�l/ noun a calculating device onwhich all manner of conversions andcomplex calculations can be made toassist in flight planningcirculate

circulate /�s%�kjυlet/ verb to moveround in such a way as to arrive at thepoint of departure � Water circulatesvia the radiator and pump through tothe engine block itself.circulation

circulation /�s%�kjυ |�leʃ(ə)n/ nounthe act of moving round in such a wayas to arrive at the point of departure �

The general circulation is indicated bythe arrows. � cyclonic circulation thecirculation of air which, if viewed fromabove, is anticlockwise in the northernhemisphere and clockwise in the south-ern hemispherecirculatory

circulatory /�s%�kjυ |�let(ə)ri/ adjec-tive moving around a circuit � a self-contained re-circulatory oil systemcircumference

circumference /sə|�k�mf(ə)rəns/noun the distance around the edge of acircle � The angle subtended by an arc

equal to one 360th part of the circum-ference of a circle is called one degree.circumstancecircumstance /�s%�k�mstns/ noun acondition which affects something in agiven situation � in some circum-stances, under certain circumstancesin some particular situationscirro-cirro- /srəυ/ prefix high altitude, i.e.above 20,000 feetcirrocumuluscirrocumulus /�srəυ |�kju�mjυləs/noun a layer of broken cloud at about20,000 feetcirrostratuscirrostratus /�srəυ |�strɑ�təs/ noun alayer cloud at about 20,000 feetcirruscirrus /�srəs/ noun a high cloud in amass of separate clouds which areformed of ice crystalsCivil Aviation AuthorityCivil Aviation Authority /�svl�evi|�eʃ(ə)n ɔ�|�θɒrəti/ noun theorganisation which licences operators,aircraft and employees for non-military,especially commercial aviation. Abbre-viation CAACivil Aviation PublicationCivil Aviation Publication /�svl�evi|�eʃ(ə)n �p�blkeʃ(ə)n/ noun abook, etc., published by the Civil Avia-tion Authority, each publication havingits own reference number � The proce-dure for obtaining a bearing can befound in CAP 413. Abbreviation CAP

COMMENT: CAA (Civil AviationAuthority) publications are referred toas CAPs and each has a referencenumber for identification: theprocedure for obtaining a bearing isdescribed in CAP 413.

cladclad /kl�d/ verb to protect by covering� Alloys can be protected from corro-sion by cladding the exposed surfacewith a thin layer of aluminium.clamshell doorclamshell door /�kl�mʃel dɔ�/ nounthe hinged part of a thrust reverser �

Clamshell doors are hydraulically orpneumatically opened, and direct theexhaust gases forwards to producereverse thrust.classificationclassification /�kl�sf |�keʃ(ə)n/noun the act of putting things intogroups or classes because they possessparticular common features � Classifi-cation of aircraft consists of a multi-level diagram with each categorydivided into sub-categories. � A full


45 climatic zone

classification of layer cloud is given inthe table.classify

classify /�kl�sfa/ verb to groupitems so that those with similar charac-teristics are in the same group � Precip-itation is classified as light, moderateor heavy according to its rate of fall. �

The weather associated with visibilityreductions by particles suspended in theatmosphere is classified either as fog,mist, haze, or smoke.clearclear /klə/ adjective 1. referring toconditions in which it is easy to see, e.g.with no cloud or fog � a clear sky a skywith no cloud � a clear winter night anight with no fog, mist or other condi-tions which might impair visibility 2.possible to easily see through 3. withnothing blocking the way � clear run-way, the runway is clear nothing is onthe runway � keep the exits clear donot put anything and do not stand infront of the exits 4. away from 5. easy tohear � clear of cloud either above orbelow cloud � keep clear (of) keepaway (from) 6. easy to understand � Theexplanation is very clear. 7. understood8. understood � is it clear? do youunderstand? � verb 1. to remove ablockage or some other unwanted effectwhich prevents a system from workingcorrectly � A heater element is fitted toclear the detector of ice. 2. to disappear� In winter frost and fog are slow toclear. 3. to make sure that it is all rightto do something � clear it with the CFImake sure that the CFI agrees with therequest 4. to officially ask people toquickly leave a given area or place � toclear the building to quickly leave thebuilding

‘…the principles of weight and balanceshould have been learned by all pilotsduring their initial training, but it is clearthat, afterwards, some forget’ [CivilAviation Authority, General AviationSafety Sense Leaflet]

COMMENT: On 27th March 1977 twoBoeing 747s collided on the runway atLos Rodeos airport Tenerife in poorvisibility, resulting in 575 deaths. AKLM 747 commenced take-off while aPan Am 747 was still taxiing towards iton the same runway. There was clear-ly a breakdown in communications,

perhaps a misunderstood radio call.The Pan Am aircraft had been askedby the controller, who was unable tosee either aircraft due to low cloud,‘Are you clear of the runway?’ TheKLM aircraft had already commencedthe take-off roll without clearance. It ispossible that the KLM pilot mistook thecall to the other aircraft thinking that hewas ‘clear to take off’.

clear air turbulenceclear air turbulence /�klər eə�t%�bjυləns/ noun turbulence encoun-tered in air where no cloud is present(NOTE: CAT is often associated with thejet stream.)clearanceclearance /�klərəns/ noun 1. a spacemade to allow for the movement ofhardware relative to other hardware �

clearance between rocker arm andvalve tip 2. official permission � Obtainclearance for IFR flight. 3. the disap-pearance of something unwanted, oftenrain, fog or snow � Low temperaturescaused a delay in the clearance of fog.clearance limitclearance limit /�klərəns �lmt/the point to which an aircraft is allowedto proceed when granted an air trafficcontrol clearanceclear iceclear ice /�klər �as/ noun ice whichis glass-like rather than whiteclear passclear pass /�klə �pɑ�s/ noun anexam result which is in no doubtclear to landclear to land /�klə tə �l�nd/ nounair traffic control permission to landclimateclimate /�klamət/ noun weather con-ditions particular to a given area � Med-iterranean climate � tropical climate �temperate climate a type of climatewhich is neither very hot in summer norvery cold in winter. � continentalclimaticclimatic /kla |�m�tk/ adjective refer-ring to climate or weather conditionsparticular to a given area � The aircraftforward speed and altitude as well asclimatic conditions will influence thevalue of thrust.climatic zoneclimatic zone /kla|�m�tk zəυn/noun one of the eight areas of the Earthwhich have distinct climates

COMMENT: The climatic zones are: thetwo polar regions (Arctic andAntarctic); the boreal zone in thenorthern hemisphere, south of theArctic; two temperate zones, one in


climatology 46

the northern hemisphere and one inthe southern hemisphere; twosubtropical zones, including thedeserts; and the equatorial zone whichhas a damp tropical climate.

climatologyclimatology /klamə|�tɒləd"i/ nounthe science of the study of climate �

Although pilots do not need to beexperts in climatology, they should havea good understanding of the factorswhich produce changes in the weather.climbclimb /klam/ noun the act of increas-ing altitude by use of power � Fine pitchenables full engine speed to be usedduring take-off and climb. Oppositedescent � verb to increase altitude byuse of power � After take-off, the air-craft climbed to 5,000 ft. Oppositedescendclimb-outclimb-out /�klam |�aυt/ noun a flightafter take-off from 35 feet to 1,500 feetduring which undercarriage and flapsare retracted � Turn right after climb-out.clockwiseclockwise /�klɒkwaz/ adjective,adverb describing a circular movementin the same direction as the hands of aclock � a clockwise direction � The rel-ative bearing indicated is measuredclockwise from the nose of the aircraft.Opposite anticlockwiseclogclog /klɒ$/ verb to prevent movementof fluid through a pipe, etc., because ofa build-up of solid matter � Most filtersallow unfiltered fluid to pass to the sys-tem when the filter becomes clogged.closeclose /kləυz/ verb to shut � Close thedoor.closureclosure /�kləυ"ə/ noun the act of clos-ing or shutting � The voltage regulatoris turned on by the closure of the gener-ator control relay.cloudcloud /klaυd/ noun a mass of watervapour or ice particles in the sky thatcan produce rain

COMMENT: The most important typesof cloud are the following:altocumulus, cloud formed at about12,000 feet as a layer of roundedmass with a level base; altostratus,cloud formed as a continuous layerbetween 6,000 and 20,000 feet usuallyallowing the sun or moon to be seenfrom the surface; cirrocumulus, a

layer of broken cloud at about 20,000feet; cirrostratus, layer cloud at about20,000 feet; cirrus, cloud made of icecrystals at 25,000 – 40,000 feetappearing as hair-like formations;cumulonimbus, cloud formed as atowering mass and often associatedwith thunderstorms; cumulus, cloudformed in rounded masses with a flatbase at low altitude, resulting from upcurrents of air; nimbostratus, thickdark layer cloud at low altitude fromwhich rain or snow often falls (nimbus= rain cloud); stratocirrus, cloudsimilar to cirrostratus but morecompact; stratocumulus, a layer ofconnected small clouds at low altitude.

cloud basecloud base /�klaυd bes/ noun thebottom part of a layer of cloud � In gen-eral, the lower the cloud base, the lessheat is lost by the earth.cloud ceilingcloud ceiling /�klaυd �si�lŋ/ nounthe height above the ground or water ofthe base of the lowest layer of cloudcloud groupcloud group /�klaυd $ru�p/ noun acollection of different cloud typeswhich have similarities, e.g. stratuscloudscmcm abbreviation centimetreco-co- /kəυ/ prefix together � co-axialhaving the same axis � co-located hav-ing the same locationcoalescecoalesce /�kəυə |�les/ verb to jointogether to form a large mass or number� The moisture in the air coalesces intolarge water droplets.coalescencecoalescence /�kəυə |�les(ə)ns/ nounthe act of joining together to form alarger mass or number � Coalescence ofwater vapour in the atmosphere formslarger droplets of water.coastcoast /kəυst/ noun an area where theland meets the sea � Valentia is situatedon the coast of south west Ireland.coastalcoastal /�kəυst(ə)l/ adjective refer-ring to the coast � coastal area an areanear a coast � Land and sea breezesoccur in coastal areas.coastal refractioncoastal refraction /�kəυst(ə)l r |

�fr�kʃən/ noun change in direction ofwaves when a signal crosses a coastlinefrom sea to landcoastlinecoastline /�kəυstlan/ noun the out-line of a coast seen from a distance or


47 collapse

on a map � It is normally easy to iden-tify a coastline or island.coatcoat /kəυt/ noun a thin covering of asubstance such as paint � The coats ofpaint on a large aircraft significantlyincrease its weight. � verb to cover witha thin layer of a substance such as paint� Metals are coated for protectionagainst corrosion.coatingcoating /�kəυtŋ/ noun 1. a thin layerof a substance � There are two coatingson the inside of CRT screens. 2. the actof covering with a thin layer of a sub-stancecockcock /kɒk/ noun a manually controlledvalve or tap to control the flow of a liq-uid � It is necessary to have a mastercock for each engine.cockpitcockpit /�kɒkpt/ noun the forwardarea in an aircraft from where the air-craft is controlled by the pilot � In thecase of an in-flight oil loss, a warningindicator will light in the cockpit.

‘…in the cockpit of the future there willbe two animals, a pilot and a dog. Thepilot will be there to feed the dog, and thedog will be there to bite the pilot if he triesto touch anything’ [NYT News Service]

codecode /kəυd/ noun 1. a system of num-bers, letters or symbols used to repre-sent language which has to be learnedand decoded in order for the receiver tounderstand the meaning 2. a series ofpulses by which an aircraft transponderreplies to a signal from the groundcodesharecodeshare /�kəυdʃeə/ noun � code-share deal an agreement between air-lines regarding connecting flights � Thetwo airlines have entered into a code-share deal for flights between Dubaiand Bangkok.codeshare partnercodeshare partner /�kəυdʃeə�pɑ�tnə/ noun an airline which has anagreement with another airline regard-ing connecting flightscodesharingcodesharing /�kəυdʃeərŋ/ noun 1.a procedure which allows travellers touse connecting flights between one air-line and another partner airline forworldwide destinations 2. an arrange-ment by which two airlines sell seats onthe same flight using their own flightnumbers

coefficientcoefficient /�kəυ|�fʃ(ə)nt/ noun amathematical quantity placed beforeand multiplying anotherC of AC of A abbreviation certificate of air-worthinessC of GC of G abbreviation centre of gravitycoilcoil /kɔl/ noun a device consisting ofcoiled wire for converting low voltageto high voltage � A voltage coil is con-nected across the generator.coiled wirecoiled wire /�kɔld �waə/ noun alength of wire twisted round and round� A coiled wire connects the terminal toearth.coincidecoincide /�kəυn |�sad/ verb to hap-pen at the same time and/or in the sameplace � When the aircraft heading isdirectly into wind or down wind, trackand heading coincide.coincidentcoincident /kəυ |�nsdənt/ adjectivehappening at the same place or at thesame time � The Earth’s true north andmagnetic north poles are not coinci-dent.colcol /kɒl/ noun an area of slack pressuregradient between two centres of high orlow pressure � The persistence andmovement of cols are governed by themovement of the adjacent pressure sys-tems.cold frontcold front /kəυld fr�nt/ noun anadvancing mass of cold air, movingunder and lifting warmer air � A coldfront brought rainy, windy conditions tothe country.collapsecollapse /kə |�l�ps/ noun a suddenand complete fall � the collapse of acompany the end of the existence of thecompany � verb 1. to fall suddenly andcompletely � The magnetic field willreach a maximum in one direction, col-lapse to zero and reach a maximum inthe opposite direction. 2. to fold or toclose suddenly and unintentionally �the undercarriage collapsed (of anapparatus) the undercarriage could notsupport the aircraft and broke orretracted on its own 3. to faint � thepassenger collapsed the passenger felland became semi- or fully unconsciousbecause of some medical problem

‘…as the aeroplane slid off the runway,the left landing gear collapsed’ [Pilot]


collect 48collect

collect /kə|�lekt/ verb 1. to gather overa period of time � Any given object willusually collect ice more quickly at highspeed. 2. to take something or to picksomething up from a placecollection

collection /kə |�lekʃən/ noun 1. anumber of things brought together � acollection of vintage aircraft 2. an act ofbeing collected by somebody � Thedocuments are in the office awaitingcollection.collide

collide /kə |�lad/ verb to bump or tocrash into something � The aircraft leftthe runway and collided with a firetruck.collisioncollision /kə |�l"(ə)n/ noun a crashbetween two objects, two vehicles, etc.� If there is a risk of collision, altercourse to the right. � collision avoid-ance the prevention of collisions by tak-ing measures beforehand to ensure thatthey do not happencolumn

column /�kɒləm/ noun 1. a body offluid or solid with a tall, narrow shape �Torricelli first demonstrated that theatmosphere has weight by showing thatit can support a column of liquid. 2. avertical section of a table in a document� Column four of the table shows thetotals of the other three columns.combat

combat /�kɒmb�t/ verb to fightagainst � Fire extinguishers are pro-vided to combat fire.combat aircraftcombat aircraft /�kɒmb�t�eəkrɑ�ft/ noun aircraft designed forwarfarecombination

combination /�kɒmb|�neʃ(ə)n/noun two or more things broughttogether to form one � The combinationof wind direction and wind speed iscalled velocity.combine

combine /kəm |�ban/ verb to bringtwo or more things together to makeone � The stabilising channels for ailer-ons and elevators are combined. �

Thrust and lift combine to overcomedrag and gravity.combustible

combustible /kəm |�b�stəb(ə)l/adjective burning or igniting easily �combustible materials materialswhich will catch fire easily, e.g. wood,paper, etc.

combustion

combustion /kəm |�b�stʃən/ nounburning, especially that which takesplace in an engine � The heat generatedby combustion is considerable.combustion chamber

combustion chamber /kəm |

�b�stʃ(ə)n �tʃembə/ noun the part ofthe cylinder in a piston engine wherethe ignition of the fuel/air mixture takesplacecombustor

combustor /kəm |�b�stə/ noun thepart of a jet or gas-turbine engine thatburns fuel to produce power. It consistsof the fuel injection system, the igniter,and the combustion chamber.command

command /kə |�mɑ�nd/ noun an order� the command to evacuate the orderto leave the aircraft in an emergency �in command having responsibility forand authority over � verb to order some-thing to be done � The captain com-manded the evacuation of the aircraft.commander

commander /kə |�mɑ�ndə/ noun apilot in control of, and responsible for,the aircraft and its contents during flighttime � the commander of an aircraftthe member of the flight crew specifiedby the operator as being the commandercommence

commence /kə |�mens/ verb to start todo something � commence the evacua-tion start getting people out of the air-craftcommercial

commercial /kə |�m%�ʃ(ə)l/ adjectivereferring to a business activity � com-mercial aviation flying as a businessenterprisecommercial aircraft

commercial aircraft /kə |�m%�ʃ(ə)l�eəkrɑ�ft/ noun aircraft used to carrycargo or passengers for paymentCommercial Pilot’s Licence

Commercial Pilot’s Licence /kə |

�m%�ʃ(ə)l �paləts �las(ə)ns/ noun thelicence that a person requires to bepilot-in-command of public transportaircraft certified for single-pilot opera-tions. Abbreviation CPLcommon sense

common sense /�kɒmən �sens/noun ordinary good sense � You shoulduse your common sense as well as fol-low the rules if a passenger feelsunwell.comms

comms /kɒmz/ abbreviation commu-nications


49 compensatecommunicate

communicate /kə |�mju�nket/ verbto make contact with somebody in orderto pass information � The cabin attend-ants should communicate with the cap-tain.communication

communication /kə |�mju�n |

�keʃ(ə)n/ noun the act of passing infor-mation to somebody usually, but notalways, by using language � Two meth-ods of communication are available tocrew members – language and handsignals.communication link

communication link /kə |�mju�n |

�keʃ(ə)n �lŋk/ noun a telephone orradio connection, as between theground crew and flight deck while anaircraft is preparing for departurecommunications

communications /kə |�mju�n |

�keʃ(ə)nz/ plural noun a system ofpassing information � satellite commu-nications � VHF communications areallocated the frequency bracket 118–137 MHz. Abbreviation commscommutator

commutator /�kɒmjutetə/ noun adevice containing metal bars connectedto the coils of a generator to produceelectrical current � As the power outputrequired is DC not AC, a commutator isfixed at one end of the armature.compact

compact /kəm |�p�kt/ adjectivesmall, close together, or not takingmuch space � The annular system, asused on modern aircraft, provides acompact system, and, for the same out-put and mass flow, a shorter system. �

verb 1. to make smaller or more denseby pressing 2. to compress, by drivingover with heavy machinery � When tax-iing on grass, aircraft wheels compactthe earth as the aircraft moves over it.compaction

compaction /kəm |�p�kʃ(ə)n/ nounthe act of pressing things together toform one, or of compressing somethingto make it hard � The speed of impactwhen the aircraft passes through asnowstorm causes compaction of snow-flakes into a solid mass on leadingedges and air-intakes.comparable

comparable /�kɒmp(ə)rəb(ə)l/adjective possible to compare equallywith something else � Titanium is non-magnetic and has an electrical resist-

ance comparable to that of stainlesssteel.comparatorcomparator /kəm |�p�rətə/ noun adevice to compare two things � Theautopilot comparator monitors theoperation of the elevator and aileronchannels.comparecompare /kəm |�peə/ verb to find thesimilarities and dissimilarities betweentwo or more things � When the chart isproperly orientated, it is easier to com-pare the distance between landmarkson the ground with their correspondingdistances on the chart. � An aneroidbarometer is small compared with amercury barometer. (NOTE: Comparewith is regarded by some as betterusage than compare to.)comparisoncomparison /kəm |�p�rs(ə)n/ nouna statement expressing the differencesand similarities between two or morethings � A table showing a comparisonof fixed points on various temperaturescales is given on page three.compartmentcompartment /kəm |�pɑ�tmənt/noun a small space or area in a structurefor a particular purpose � engine com-partment � crew compartment the areareserved for crewcompasscompass /�k�mpəs/ noun an instru-ment usually with a magnetic needlewhich always points to the magneticnorthcompass bearingcompass bearing /�k�mpəs�beərŋ/ noun a direction or positionrelative to a fixed point measured indegrees on a compasscompatibilitycompatibility /kəm |�p�t|�blti/noun the ability of a component to oper-ate successfully with other components� Problems of compatibility caused thecomputerised system to malfunction.compatiblecompatible /kəm |�p�tb(ə)l/ adjec-tive referring to a component or systemwhich can be used with a different com-ponent or system without causing anyproblems � Computer softwaredesigned for one particular system maynot be compatible with other systems.compensatecompensate /�kɒmpənset/ verb 1.to make up for the loss of something �

The floor covering may be designed tocompensate for temperature, pressuri-


compensation 50

sation and bending loads. � The fall inair temperature increases the air den-sity and so compensates to some extentfor the loss of the thrust due to atmos-pheric pressure. 2. to give money to aperson or organisation to make up for aphysical or financial loss � The moneyoffered by the company did not compen-sate for the injuries she received in theaccident.compensation

compensation /�kɒmpən |�seʃ(ə)n/noun money paid to an individual ororganisation to replace or make up forphysical or financial loss � The com-pany paid out $2 million in compensa-tion to the families of those who losttheir lives in the tragedy.compilationcompilation /�kɒmp|�leʃ(ə)n/ nounthe putting together of suitable informa-tion � The manual is a compilation ofmaterials used by each of the instruc-tors.compilecompile /kəm |�pal/ verb to puttogether a number of pieces of informa-tion � Aviation routine weather reportsare compiled half-hourly or hourly atfixed times.complementcomplement /�kɒmplment/ verb tofit in with and improve the performanceof something � Ultra-sonic detection isused to complement other methods offlaw detection.complementarycomplementary /�kɒmpl|

�ment(ə)ri/ adjective the fact of fittingin with and improving the performanceof something � SSR is complementaryto the primary radars used by ATC.complete

complete /kəm |�pli�t/ adjective 1.containing all the parts it should contain� The centre section can be constructedeither as a complete unit or as two sep-arate units. 2. absolute and total � verb1. to finish or make whole � Thenumber of revolutions for the crank-shaft to complete a full cycle is alwaystwo. � complete the work to continueuntil the work is finished 2. to fill ininformation � complete the flight planto fill in the required information in theflight plancompletioncompletion /kəm |�pli�ʃ(ə)n/ noun thesatisfactory finishing of a task � It isimportant to carry out an inspection of

an aircraft after completion of de-icingoperations.complexcomplex /�kɒmpleks/ adjective com-plicated and therefore possibly difficultto understand � Of all the pre-departureactivities, route planning is one of themost complex. � noun 1. a whole madeup of many different parts � a cumulo-nimbus cloud complex a collection ofcumulonimbus clouds forming a system2. a building made up of many differentparts � the terminal three complex themain building and associated buildingswhich together make up terminal threecomplexitycomplexity /kəm |�pleksti/ noun thecondition of being complex, or a com-plication � Up-to-date design does notnecessarily mean structural complexity.complicatecomplicate /�kɒmplket/ verb tomake more difficult � Map reading isoften complicated by seasonal varia-tions.complicatedcomplicated /�kɒmplketd/ adjec-tive not easy to understandcomplicationcomplication /�kɒmpl |�keʃ(ə)n/noun a difficulty or problem � The com-plication with the Mercator’s projectionis that great circle directions must beconverted to rhumb line directions bythe application of conversion anglebefore they can be plotted.complycomply /kəm |�pla/ verb to be or dowhat is required by an instruction or law� Equipment and furnishings of modernjet transports must comply with safetyregulations. � Passengers must complywith the no-smoking signs. (NOTE: com-plying – complied)componentcomponent /kəm |�pəυnənt/ noun 1.a part of an aircraft, aircraft system orpiece of equipment � The undercar-riage is made up of a number of differ-ent components. 2. one part of a forcesuch as wind which consists of anumber of different parts 3. a substancewhich forms part of a compoundcomposecompose /kəm |�pəυz/ verb to makesomething from a number of parts � Theatmosphere is composed of a mixture ofgases.compositecomposite /�kɒmpəzt/ adjectivereferring to something made up of anumber of different parts � composite


51 concentration

material � The flight crew route flightplan is a composite document whichserves as a navigation log. � noun alightweight but very strong man-madematerial used in aircraft manufacturing� To make a composite it is necessary tocombine the reinforcing glass fibreswith special glue or resin. (NOTE: Theword composite was originally anadjective, but through frequent usagethe term composite material has beenshortened to composite.)

‘Canadian Aerospace Group (CAG) isworking with Pratt & Whitney Canada ona turboprop-powered version of itsWindeagle all-composite light aircraft’[Flight International 16–22 July 1997]COMMENT: Composites are used inthe construction of many modernaircraft, from gliders to aircraft such asthe Airbus A320, because they arestrong and lighter than metals.

compositioncomposition /�kɒmpə |�zʃ(ə)n/ nounthe make-up or structure of something �composition of the atmosphere thecombination of gases which make upthe atmospherecompoundcompound /�kɒmpaυnd/ adjectivereferring to something made up of twoor more parts or substances � noun asubstance made up of two or more com-ponents � A chemical compound hasqualities that are different from those ofthe substances from which it is made. �

Advances in sealing compounds havenow made fuel tanks less liable to leaks.compound wound generatorcompound wound generator/�kɒmpaυnd �wu�nd �d"enəretə/noun a generator which consists of anumber of windingscompresscompress /kəm |�pres/ verb to putunder pressure thereby reducing vol-ume � Pressure is created when a fluidis compressed.compressibilitycompressibility /kəmpresə |�blti/noun the natural ability of a substanceto change volume when under varyingpressures � In systems using very highpressure, the compressibility of the liq-uid becomes important.compressiblecompressible /kəm |�presəb(ə)l/adjective referring to something thatcan be compressed � Air is compressi-ble, but water is not.

compressioncompression /kəm |�preʃ(ə)n/ nounan act or instance of putting pressure onsomethingcompression strokecompression stroke /kəm |

�preʃ(ə)n strəυk/ noun the stage of aninternal combustion cycle when thefuel/air mixture comes under pressurefrom the upward-moving pistoncompressivecompressive /kəm |�presv/ adjec-tive referring to forces caused by pres-sure on a surface � A strut is designed towithstand compressive loads.compressive loadcompressive load /kəm |�presv�ləυd/ noun a load caused by forces act-ing in opposite directions towards eachothercompressive stresscompressive stress /kəm |�presv�stres/ noun the resistance of a body tocrushing by two forces acting towardseach other along the same straight linecompressorcompressor /kəm |�presə/ noun adevice such as a pump to compress air,in order to increase pressure � A shaftconnects the turbine to the compressor.� axialcomprisecomprise /kəm |�praz/ verb to bemade of (NOTE: The correct use of com-prise is often disputed. Some peopleregard it as a synonym for the verbconsist of, while others believe itshould be used in an opposite sense: atank, pipes, a filter, a pump and a car-burettor comprise the fuel system. It issometimes used in its passive form: thefuel system is comprised of a number ofdifferent parts.)concentrateconcentrate /�kɒnsəntret/ verb 1.to collect in a particular place ratherthan spread around � Most of the massof air is concentrated at the lowest lev-els of the atmosphere. 2. to give atten-tion and thought to something in partic-ular � This chapter concentrates oncharts. � to concentrate hard to giveall one’s thought and attention to some-thingconcentrationconcentration /�kɒnsən |�treʃ(ə)n/noun 1. the fact of being collected in aparticular place rather than spreadaround � The maximum concentrationof ozone is between 20 and 25 km abovethe Earth’s surface. 2. the act of givingattention and thought to something � In


concentric 52

the early stages of training, instrumentflying requires great concentration onthe part of the student pilot.concentricconcentric /kɒn |�sentrk/ adjectivehaving the same centre � concentriccircles circles of different diameters butwith the same centre pointconceptconcept /�kɒnsept/ noun an idea orabstract principle � The concept of openskies is not one with which everybodyagrees. � a complicated concept anidea or series of ideas or principleswhich are difficult to understandconcernconcern /kən |�s%�n/ noun 1. seriousinterest � a matter for concern some-thing which must be taken very seri-ously 2. responsibility � Attention to thewelfare of passengers is the concern ofthe cabin crew. � Safety is everybody’sconcern. � this is no concern of oursthis is nothing to do with us � verb 1. tocause somebody to feel worried � thisreport concerns me enormously I amnot at all happy about this report 2. to beabout or to be the subject of � If there isserious vibration, the crew should shutdown the engine concerned. � thisreport concerns me this report is aboutme 3. to be of interest and relevance to� the regulations concern all employ-ees the regulations apply to all employ-ees

‘…the correct storage and handling ofcargo and especially dangerous goods isan area which is of considerable concernto the Federation’ [INTER PILOT]

concreteconcrete /�kɒŋkri�t/ noun a sub-stance made of cement, sand and waterused in the construction of buildings,roads, etc. � Rock, sand and concretereflect only 10–20% of radiation.condensationcondensation /�kɒnden |�seʃ(ə)n/noun the process by which vapourchanges into liquid � If the air becomessaturated, further cooling results incondensation. Opposite evaporationcondensation trailcondensation trail /�kɒnden |

�seʃ(ə)n trel/ noun same as vapourtrailcondensecondense /kən |�dens/ verb 1. tochange from vapour to liquid form �

The most common type of hygrometer isone in which a surface in contact with

the atmosphere is cooled until moisturebegins to condense on the surface.Opposite evaporate 2. to removeunnecessary parts from a text to make itshorter � The synoptic code condensesinformation without loss of sense.condensercondenser /kən|�densə/ noun anelectrical capacitor � The condenserprevents spark plugs from arcing.conditioncondition /kən |�dʃ(ə)n/ noun 1. thepresent state of something � althoughthe aircraft is old, it is in good condi-tion the aircraft is old but well cared for2. the state of the surrounding atmos-phere � In a high relative humidity con-dition, the evaporation rate is low. �abnormal weather conditions unusualor unfavourable weather � adverseweather conditions bad weather 3. cir-cumstances 4. something on whichanother thing depends � on conditionthat only if � the flight will depart oncondition that the weather improvesthe flight will depart only if the weatherimprovesconduciveconducive /kən |�dju�sv/ adjectivefavourable, which allows something tohappen more easily � Atmospheric con-ditions conducive to the formation ofice are detected and these operate awarning system.

‘…when refuelling, ensure the aircraft isproperly earthed. The very low humidityon a crisp, cold day can be conducive to abuild-up of static electricity’ [CivilAviation Authority, General AviationSafety Sense Leaflet]

conductconduct /kən |�d�kt/ noun /�kɒnd�kt/1. a manner or way of doing something� The captain is responsible for the safeconduct of the flight. 2. behaviour � Theinvestigation found that the flightattendant’s conduct was unacceptable.� verb 1. to organise and do something;to carry out � Crew will conduct areachecks. � Security conducted a searchof the building. 2. to allow somethingsuch as electricity, heat etc. to passthrough � Water conducts electricity.conductionconduction /kən |�d�kʃən/ noun theprocess by which heat or electricitypasses through a substance � Heat istransferred to the layer of air next to theEarth’s surface by conduction.


53 connectionconductive

conductive /kən|�d�ktv/ adjectivereferring to the ability of a substance toallow heat or electricity to pass through� Steel is a conductive material. � Landmasses are less conductive than water.conductivityconductivity /�kɒnd�k |�tvti/ nounthe ability of a material to allow heat orelectricity to pass through � Because ofthe poor conductivity of air, heat istransferred from the Earth’s surfaceupwards by convection.conductor

conductor /kən |�d�ktə/ noun a sub-stance through which heat or electricitycan pass � Water and steel are goodconductors.cone

cone /kəυn/ noun a solid body with abase in the shape of a circle, and withsides which narrow to a point, or anyobject which has that shapeconfigurationconfiguration /kən |�f$jə |�reʃ(ə)n/noun the pattern or way in which thingsare arranged � configuration of an air-craft’s fuel tank system the way inwhich the tanks are laid outconfine

confine /kən|�fan/ verb 1. to limit to aparticular area � Cooling is confined tothe air in contact with the ground. � Thedamage was confined to a small area. 2.to limit to a given subject � the reportconfines itself to the incident of 3rdJanuary the report deliberately doesnot mention anything other than theincident of the 3rd Januaryconfinedconfined /kən |�fand/ adjective lim-ited, small � a confined space a smalldefined space which does not allow freemovementconfirm

confirm /kən|�f%�m/ verb to agree thatsomething is correct, or to repeat it toremove any uncertainty � The attitudeindicator shows that the aircraft is in anose down attitude and the increasingairspeed confirms that the aircraft is notin level flight. � Can you confirm thatthe instructor was flying the aircraft atthe time of the collision? � VHF and/orUHF radio aids confirm ADF bearings.

COMMENT: Cross-checking of certainflight instruments is used to confirmreadings from other instruments, e.g.the airspeed indicator and verticalspeed indicator confirm pitchinformation from the attitude indicator.

conformconform /kən |�fɔ�m/ verb to corre-spond to required standards � Fuelsmust conform to strict requirements. �to conform to regulations to do what isrequired by rules and regulationsconformalconformal /kən|�fɔ�m(ə)l/ adjectiverepresenting angles, bearings, etc., cor-rectly � Lambert’s conformal projec-tioncongestioncongestion /kən |�d"estʃən/ noun asituation where there are too many peo-ple or vehicles in a confined space forthem to be able to move freely � Whenleaving the aircraft in an emergency, toavoid congestion, passengers should bedirected to move away from exitsquickly.conicconic /�kɒnk/ adjective based on theshape of a cone � conic projection thestandard two-dimensional representa-tion of the earthconicalconical /�kɒnk(ə)l/ adjective shapedlike a cone � The nose of Concorde hasa conical shape.conjunctionconjunction /kən |�d"�ŋkʃən/ noun �in conjunction with working or operat-ing together with � Built-up areas, usedin conjunction with other features suchas rivers, railways and coastlines whichare near them, are more easily identi-fied.connectconnect /kə|�nekt/ verb to join � Bat-teries are sometimes connected inseries. � A cockpit lever is connected toa needle valve in the float chamber.connecting flightconnecting flight /kə|�nektŋ �flat/noun a second aircraft which a passen-ger should arrive on time to catch, andwhich will take him or her to the finaldestination � Instead of flying direct toLondon, take the flight to Amsterdamand then take a connecting flight toLondon Heathrow.connecting rodconnecting rod /kə |�nektŋ rɒd/noun an engine part that connects thepiston to the crankshaftconnectionconnection /kə |�nekʃən/ noun 1. thepoint at which things are joined � Thereis an electrical connection to the bat-tery. 2. a link or feature that makesthings interdependent � There is a con-nection between temperature changeand altitude. 3. the process of catching


connector 54

a second aircraft to arrive at a final des-tination � Follow the ‘Flight Connec-tion’ signs.connectorconnector /kə |�nektə/ noun a devicewhich connects two or more things � Aconnector is used to connect twolengths of wire together. � Standardconnectors consist of a metal couplingwith a rubber sandwich joint.consecutiveconsecutive /kən |�sekjυtv/ adjec-tive following one another without abreak � 4, 5 and 6 are three consecutivenumbers. � a period of 28 consecutivedays 28 days following immediatelyone after the otherconsequenceconsequence /�kɒnskwəns/ nounthe result of an action � The accidentwas a consequence of the pilot’sactions. � as a consequence as a resultconsequentconsequent /�kɒnskwənt/ adjec-tive resulting � As temperature rises,there will be a consequent increase inthe volume of the gas.consequentlyconsequently /�kɒnskwəntli/adverb therefore, as a result � She waslate, consequently she missed the startof the examination.conserveconserve /kən |�s%�v/ verb to avoidusing unnecessarily � Release thebrakes when necessary and conservemain system pressure. � to conserveenergy to use only as much energy asyou really need � to conserve fuel touse as little fuel as possibleconsiderconsider /kən|�sdə/ verb to thinkcarefully about something � If the air-craft is low on fuel, the commandershould consider diverting to the nearestsuitable airport.

‘…many purchasers of flight simulatorswould argue that, when considering themajor manufacturers, there is little tochoose between them’ [Civil AviationTraining]

considerableconsiderable /kən|�sd(ə)rəb(ə)l/adjective a lot of, quite large � Therequired range of trim change is consid-erable. (NOTE: Considerable does notmean that something should bethought about, as the meaning for theverb consider might suggest.) � a con-siderable amount of fuel a lot of fuel,a large amount of fuel � a considerable

distance a long distance � considera-ble force a lot of forceconsideration

consideration /kən |�sdə |�reʃ(ə)n/noun 1. something important to remem-ber and to think carefully about � totake into consideration to rememberto include when thinking about some-thing, solving a problem or making acalculation 2. thoughtfulness, respect �to show consideration for other peo-ple and property to show respect forwhat belongs to other peopleconsist

consist /kən|�sst/ verb � to consist ofto be made up of � Layer cloud namesconsist of a prefix, according to heightof base, and a suffix according to shape.� to consist in to mean, to beconsistent

consistent /kən |�sstənt/ adjectivealways reacting or behaving in the sameway � Human hair responds in a con-sistent manner to changes in the rela-tive humidity. � consistent perform-ance performance which maintains aparticular standardconsolidate

consolidate /kən |�sɒldet/ verb tomake more solid or strong � revision ofthe subject helps to consolidate itrevision of the subject helps to set itmore firmly in the memoryconsolidation

consolidation /kən |�sɒl |�deʃ(ə)n/noun 1. a process by which somethingis made more solid or strong 2. thegrouping of goods together for ship-mentconstant

constant /�kɒnstənt/ adjectiveunchanging � the temperature of thegas remains constant the temperatureof the gas stays the same � constantpressure pressure which stays the sameconstant speed drive unit

constant speed drive unit/�kɒnstənt spi�d �drav �ju�nt/ nouna device fitted to aircraft with constantspeed propellers. Abbreviation CSDUconstant speed propeller

constant speed propeller/�kɒnstənt spi�d prə |�pelə/ noun a pro-peller with a control system which auto-matically adjusts pitch to maintainselected rpmconstant speed unit

constant speed unit /�kɒnstənt�spi�d �ju�nt/ noun a device that auto-matically keeps a propeller at a speedset by the pilot. Abbreviation CSU


55 contaminateconstituent

constituent /kən |�sttjυənt/ nounany one of the various parts that makeup a whole � Water, whether in the formof vapour, liquid or ice, is a very impor-tant constituent of the atmosphere.constitute

constitute /�kɒnsttju�t/ verb tomake up, to form � Oxygen and nitro-gen together constitute most of theatmosphere.constrain

constrain /kən|�stren/ verb 1. to pre-vent somebody from being completelyfree or from doing something they wantto do � The airline was constrained inits purchase of new aircraft by lack offinancial resources. 2. to force some-body to do something � Lack of finan-cial resources constrained the airline tocancel the purchase of new aircraft.constraint

constraint /kən |�strent/ noun some-thing that reduces freedom of action �

The number of landings per 24-hourperiod is subject to constraint.constrict

constrict /kən|�strkt/ verb to makesomething narrower, especially to makethe flow of gas or liquid more difficultby narrowing the passage throughwhich it flows � In the carburettor ven-turi, the flow of air is constricted.constriction

constriction /kən |�strkʃən/ nounthe act of constricting, or a place wheresomething is particularly narrow � Athermometer has a constriction in thebase of the tube between the bulb andthe beginning of the scale.construct

construct /kən |�str�kt/ verb 1. to puttogether � The table on page 4 can beused to construct the low level forecastfor the route. 2. to build � to constructan aircraft to manufacture or build anaircraft � Wings are constructed of lightalloy pressed ribs and an outer skin.construction

construction /kən |�str�kʃən/ noun1. the act of putting things together, orthe way in which something is puttogether � The basic construction of thelead-acid cell consists of a positiveelectrode and negative electrode. 2. abuilding � The construction of thehome-built aircraft took two years.consume

consume /kən|�sju�m/ verb 1. to useup in a given time � Drag must be over-come with thrust, which requires

engines, which in turn consume fuel. 2.to eatconsumptionconsumption /kən |�s�mpʃ(ə)n/noun 1. the amount used up in a giventime � Fuel consumption is higher inbigger, more powerful engines. 2. theprocess of using up fuel or otherresources 3. the amount eaten 4. the actof eatingcontactcontact /�kɒnt�kt/ noun 1. touch � incontact with touching � The air in con-tact with the Earth’s surface cools. 2. �to be in contact with to communicatewith e.g. by telephone or radio � to bein visual contact to see � to make con-tact to communicate � to lose contactto stop communicating � ATC lost con-tact with the aircraft. 3. a person whocan be contacted in order to get some-thing done � I have a contact inMadrid who can help I know some-body in Madrid who can help 4. an elec-trical connection � Dirty contacts werethe cause of the problem. � verb to getin touch with somebody e.g. by radio ortelephone � The captain couldn’t con-tact ATC.contact breakercontact breaker /�kɒnt�kt�brekə/ noun a mechanically operatedswitch which is timed to break the pri-mary circuit when maximum current isflowingcontact flightcontact flight /�kɒnt�kt flat/ nouna method of navigation for aircraft inwhich the pilot or crew use no naviga-tional aids, but find their way byobserving visible features of the groundcontact numbercontact number /�kɒnt�kt�n�mbə/ noun a telephone numberwhere information can be obtainedcontaincontain /kən|�ten/ verb to hold, tohave inside � Most clouds contain somesuper-cooled water droplets. � Thebooklet contains details of the airline’sflight schedule.containercontainer /kən |�tenə/ noun a box,bottle, etc., which holds something else� A smouldering fire in a waste con-tainer could become very active due topressure changes during ascent.contaminatecontaminate /kən |�t�mnet/ verbto make something impure, harmful ordangerous � If contaminated air enters


contaminated fuel 56

the cabin, the dump valve can beopened.contaminated fuel

contaminated fuel /kən |

�t�mnetd �fju�əl/ noun fuel whichcontains an unwanted substance, suchas water, and is therefore dangerous tousecontamination

contamination /kən |�t�m|

�neʃ(ə)n/ noun a process by which aliquid, gas or object is made unusablebecause impurities or foreign matter areallowed into or onto it � contaminationof air air pollution � fuel contamina-tion a situation in which fuel becomesunusable because an unwanted sub-stance such as water gets into it �nuclear contamination damage doneto an object, person or substancebecause of contact with nuclear radia-tioncontent

content /�kɒntent/ noun the amountof a substance that is contained withinsomething, often expressed as a per-centage � The stratosphere is a layer inwhich the water vapour content is low.� the moisture content of the atmos-phere the amount of water vapour in theaircontinent

continent /�kɒntnənt/ noun one ofthe seven great land masses of the Earth� the continent of Europe

COMMENT: The seven continents are:Asia, Africa, North America, SouthAmerica, Australia, Europe andAntarctica.

continental

continental /�kɒnt |�nent(ə)l/ adjec-tive referring to a continentcontinental climate

continental climate/�kɒntnent(ə)l �klamət/ noun thetype of climate found in areas wherethere is no effect from the seacontingencycontingency /kən |�tnd"ənsi/ nounsomething which might happen in thefuture and therefore must be plannedforcontingency reserve fuel

contingency reserve fuel /kən |

�tnd"ənsi r |�z%�v �fju�əl/ noun fuelwhich would only be used in an unusualsituation such as a diversioncontinuity

continuity /�kɒnt|�nju�ti/ noun con-tinuing � continuity of precipitationcontinuing rain, snow or hail

contourcontour /�kɒntυə/ noun the shape ofsomethingcontour chartcontour chart /�kɒntυə tʃɑ�t/ nounchart which shows areas of high andlow groundcontour gradientcontour gradient /�kɒntυə�$rediənt/ noun steepness of changein elevationcontour linecontour line /�kɒntυə lan/ noun aline on a map or chart joining points ofequal elevationcontractcontract /kən |�tr�kt/ verb to becomesmaller in volume � Liquids will expandor contract as a result of temperaturechanges. Opposite expandcontractioncontraction /kən|�tr�kʃən/ noun thedecrease in volume of a substancebrought about by cooling � Due to con-traction, the length of a mercury columnshortens. Opposite expansioncontrailcontrail /�kɒntrel/ noun same asvapour trailcontrastcontrast /�kɒntrɑ�st/ noun 1. theamount of light and dark in somethingseen � Contrast and colour enable apilot to identify ground features. 2. thedifference between two things � Thereis an enormous contrast between theperformance of the two aircraft. � incontrast to when compared with � Airat altitude is cold in contrast to air atthe surface.contributecontribute /kən|�trbju�t/ verb togive or provide as part of the whole �

Exhaust gases contribute to enginepower. � although the weather wasbad, pilot error contributed to theaccident pilot error was partly respon-sible for the accidentcontributioncontribution /�kɒntr |�bju�ʃ(ə)n/noun 1. the part that something plays inmaking or causing something � The dif-ferences in the effect of solar radiationon land and sea make the biggest con-tribution to weather and climate. 2. theact of contributing or something, espe-cially money, that is given or providedcontributorcontributor /kən|�trbjυtə/ noun aperson or thing that contributes tosomething � There are other factorswhich cause the division of the loweratmosphere into two layers but theozone effect is a major contributor.


57 conventionalcontrol

control /kən |�trəυl/ noun 1. theauthority or ability to direct somebodyor something 2. � crowd control themanagement of the movements of largenumbers of people 3. checking or exam-ining � verb to direct, to manage or tomake a machine, system, procedure,etc., work in the correct way � The pur-pose of the centrifugal switch is to con-trol the starting and ignition circuits.(NOTE: The word control in English isused in a different way to similar wordsin other languages. In English, the verbcheck is more often used to mean ‘lookat and verify’ while control is used inthe sense of ‘to make something workin a particular way’: the yoke and rud-der pedals are used to control themovement of the aircraft. Note also:controlling – controlled.)control area

control area /kən |�trəυl �eəriə/ nounthe airspace above a particular area onthe ground, which is controlled by aparticular authority. Abbreviation CTAcontrol column

control column /kən |�trəυl �kɒləm/noun the main hand control used by thepilot to control the aircraft in roll andpitchcontrolled airspace

controlled airspace /kən|�trəυld�eəspes/ noun airspace which is gov-erned by rules and regulations whichpilots must comply with. AbbreviationCAScontroller

controller /kən |�trəυlə/ noun 1. adevice which ensures that somethingoperates in the correct way � the propel-ler speed controller 2. a person whomanages systems to ensure the smoothoperation of procedurescontrols

controls /kən |�trəυlz/ plural nounmanual or automatic devices that areused to control a machine, a system,etc., or to make a machine, a system,etc., work in a correct way � the pilot atthe controls of the aircraft the pilotwho is operating the flying controlscontrol surfaces

control surfaces /kən |�trəυl�s%�fsz/ plural noun moveable aero-foils, usually on the wings and tail-plane, which can be operated from thecockpit by the pilot, thus changing air-craft attitude

control towercontrol tower /kən |�trəυl �taυə/noun a tall building on an airfield fromwhich air-traffic controllers organiseincoming and outgoing aircraft byspeaking to their pilots by radiocontrol zonecontrol zone /kən|�trəυl zəυn/ nouna designated ATC area. AbbreviationCTRconvectionconvection /kən |�vekʃ(ə)n/ noun theprocess by which hot air rises and coolair descends � Heat is transferred fromthe Earth’s surface upwards largely byconvection.convectiveconvective /kən |�vektv/ adjectivereferring to convection, or somethingwhich is affected by the vertical circula-tion of air � convective movementmovement caused by warm air risingand cool air descendingconvective cloudsconvective clouds /kən |�vektv�klaυdz/ plural noun clouds formed as aresult of warm moist air rising and con-densing at altitudeconvenienceconvenience /kən |�vi�niəns/ noun 1.personal comfort and benefit � Readinglights are provided for passengers’ con-venience. � at your convenience whenit is least troublesome for you 2. ease ofunderstanding � For convenience wewill assume that the Earth is round. 3.usefulness, or easiness to useconvenientconvenient /kən |�vi�niənt/ adjective1. useful � The circular slide rule has aconvenient scale for converting weightsand volumes. 2. suitable and unlikely tocause problems � We must arrange aconvenient time and place for the meet-ing.conventionconvention /kən |�venʃən/ noun 1. anidea which because of long usage hasbecome normal and accepted � By con-vention, wind direction is the directionfrom which the wind blows. 2. a meetinginvolving large numbers of people andlong discussions in order to arrive at anagreed course of action often outlinedin a public statement � the Tokyo Con-ventionconventionalconventional /kən |�venʃ(ə)n(ə)l/adjective usual or familiar to most peo-ple � Every pilot must know the conven-tional symbols used for depicting thevarious ground features on charts.


converge 58convergeconverge /kən|�v%�d"/ verb to cometogether at a particular point � Meridi-ans converge towards the poles. � air-craft on converging courses aircraft oncourses which may eventually be tooclose to each other if no correctiveaction is taken. Opposite divergeconvergenceconvergence /kən |�v%�d"əns/ nounthe fact of coming together at a particu-lar point � The inter-tropical conver-gence zone is the zone in which thetrade winds from the two hemispheresapproach each other. � There is conver-gence of meridians of longitude at thenorth and south poles. Opposite diver-genceconverseconverse /�kɒnv%�s/ noun the oppo-site � The converse of port is starboard.� warm air rises – the converse is alsotrue in other words, cool air descendsconversionconversion /kən |�v%�ʃ(ə)n/ noun 1. achange to a different system or set ofrules � The conversion of km into nm isnot difficult. 2. � conversion courseflying training which enables and qual-ifies a pilot to fly a different aircrafttypeconvertconvert /kən |�v%�t/ verb to change to adifferent system or set of rules � to con-vert km into nm � How do you convertdegrees C into degrees F?converterconverter /kən |�v%�tə/ noun a devicewhich alters the form of something � Abackup converter converts the alternat-ing current power into direct current.convertibleconvertible /kən |�v%�təb(ə)l/ adjec-tive possible to change easily, e.g. to fitin with a new system or set of standards� The statute mile, unlike the nauticalmile, is not readily convertible intoterms of angular measurements.conveyconvey /kən |�ve/ verb to carry ormove from one place to another � Alarge number of tubes convey the cool-ing medium through the matrix. � Busesare used to convey passengers from theaircraft to the terminal building. � toconvey information to pass informa-tion from one person to another, or fromone place to anothercoolcool /ku�l/ adjective a little cold � coolweather weather which is not hot,warm nor very cold � verb to become or

cause to become less hot � The airflowis used to cool the oil. � air-cooledcoolantcoolant /�ku�lənt/ noun a substance,usually liquid, used to cool somethingsuch as an engine � radiator coolant �

The coolant is sprayed into the combus-tion chamber inlet.coolercooler /�ku�lə/ noun a device for cool-ing � A self-contained system, consist-ing of an oil tank, pump, filter, cooler,and oil jets, lubricates the auxiliarypower unit.coolingcooling /�ku�lŋ/ noun the action ofmaking something cool � the cooling ofthe oil by the airflow � adjective reduc-ing the temperature of something �cooling medium a substance whichreduces the temperature of another sub-stance or materialcoordinatecoordinate /kəυ |�ɔ�dnət/ verb 1. tobring together the various parts of a pro-cedure or plan to ensure that the opera-tion works correctly � It is the task ofair traffic controllers to coordinate themovement of traffic in and out of a ter-minal. 2. to make different parts of thebody work well together � During ahover, helicopter pilots must be able tocoordinate movements of both handsand feet.coordinated flightcoordinated flight /kəυ |�ɔ�dnetd�flat/ noun flight, especially duringturns, in which the horizontal and verti-cal forces acting on the aircraft are inbalance � In coordinated flight, the ballin the turn coordinator will be in thecentre.

COMMENT: The ball in the balanceindicator of the turn coordinator showsthe pilot if the aircraft is in coordinatedflight or if it is slipping or skidding.When the ball moves to the left thepilot should apply left rudder pedalpressure, if the ball moves to the right,the pilot should apply right rudderpedal pressure.

Coordinated Universal TimeCoordinated Universal Time/kəυ |�ɔ�dnetd �ju�n |�v%�s(ə)l tam/noun time used in aviation based on the24-hour clock format. � GMTcoordinatescoordinates /kəυ |�ɔ�dnəts/ pluralnoun values used to locate a point on agraph or a map � The airfield can beseen on the map at coordinates B:12.


59 corrodecoordinationcoordination /kəυ|�ɔ�d |�neʃ(ə)n/noun 1. the process of bringing togetherthe various parts of a procedure or planto ensure that it works correctly � A res-cue coordination centre is set up to con-trol the emergency. 2. the ability to usedifferent parts of the body together well� A pilot must have good hand/eyecoordination.copecope /kəυp/ verb to manage to dosomething, often with some difficulty �In heavy rainstorms, the windscreenwipers may not be able to cope. � Theaircraft structure must be able to copewith increased loads caused by turningmovement.copilotcopilot /�kəυpalət/, co-pilot noun alicensed pilot who is second in com-mand to the captain of an aircraft � Thecopilot landed the aircraft.coptercopter /�kɒptə/ noun same as heli-copter (informal )cordcord /kɔ�d/ noun a strong thread, usu-ally of nylon � Tyres are of pure rubberand are either cord-strengthened orreinforced. (NOTE: Cord is used to rein-force tyres.)corecore /kɔ�/ noun the central part, theheart of something � The primary wind-ings consist of heavy gauge wiremounted on a soft iron core. � the coreof a problem the central, most funda-mental part of a problemCoriolis forceCoriolis force /�kɒri |�əυls �fɔ�s/noun force which accelerates the move-ment of a rotating mass perpendicularto its motion and towards the axis ofrotation � The Coriolis force explainswhy wind patterns are clockwise in thenorthern hemisphere and anti-clock-wise in the southern hemisphere.

COMMENT: The Coriolis force acts at aright angle to wind direction and isdirectly proportional to wind speed. Itis named after G. G. Coriolis, a Frenchengineer who died in 1843.

correctcorrect /kə|�rekt/ adjective right �correct tyre pressure the pressure atwhich the tyres should be maintained �

verb 1. to adjust in order to make right� A servo-motor fitted in the elevatortrim system will automatically correctfor loads. � Calibrated airspeed or rec-

tified airspeed is indicated airspeedcorrected for instrumentation andinstallation error. 2. to mark answersright or wrong, as in an examination �

The instructor has corrected the stu-dents’ examination papers.correctioncorrection /kə|�rekʃ(ə)n/ noun 1. anadjustment or change made to some-thing to make it correct 2. the use of amathematical formula for adjusting aknown inaccuracy of calculation � Inapplying this correction the reading isconverted to that which would occur atmean sea level. 3. an alteration on, e.g.a test answer, which provides the rightanswer in place of the wrong answergiven � I made several corrections tothe text.correctivecorrective /kə |�rektv/ adjectivereferring to something designed to cor-rectcorrective actioncorrective action /kə |�rektv��kʃən/ noun action taken to put a situ-ation right � If the pilot realises that theplane is too high on the approach, he orshe should take corrective action imme-diately.correlatecorrelate /�kɒrəlet/ verb to measuresomething against something else inorder to form a relationship between thetwo � Power is measured not by theamount of work done, but by units ofaccomplishment correlated with time.correlationcorrelation /�kɒrə |�leʃ(ə)n/ noun ameasurable and predictable relationship� At a given speed, there is a correlationbetween time and distance.correspondcorrespond /�kɒr|�spɒnd/ verb 1. tofit with or have a direct relationshipwith � Movements of the control sur-faces correspond to movements of thepilots flying controls. 2. to be similar to� In the interests of passenger comfort,the ideal cabin conditions to maintainwould be those corresponding to sealevel.corridorcorridor /�kɒrdɔ�/ noun same as aircorridorcorrodecorrode /kə |�rəυd/ verb 1. to destroyby a slow chemical process such as rust� The sulphur and water content of tur-bine fuels tend to corrode the compo-nents of the fuel and combustion sys-


corrosion 60

tems. 2. to be destroyed by a slowchemical process such a rust � Alumin-ium will not corrode easily.corrosioncorrosion /kə|�rəυ"(ə)n/ noun thedestruction of a material by chemicalprocesses � Aluminium has a highresistance to corrosion. � anti-corro-sioncorrosion protectioncorrosion protection /kə|�rəυ"(ə)nprə |�tekʃən/ noun action and/or meas-ures taken to prevent corrosion such asrustcorrosivecorrosive /kə |�rəυsv/ adjective caus-ing corrosion � Sulphuric acid is verycorrosive.cosinecosine /�kəυ |�san/ noun a trigono-metric function defined as the length ofthe side adjacent to an angle in a right-angled triangle divided by the length ofthe hypotenuse. Abbreviation coscountercounter /�kaυntə/ verb to act againstsomething so as to remove or reduce itseffect � For level flight, lift must counterthe force of gravity. � Some people findthat swallowing hard counters theeffects of changes in pressure.counter-counter- /kaυntə/ prefix againstcounterclockwisecounterclockwise /�kaυntə |

�klɒkwaz/ adjective, adverb US sameas anticlockwisecounter-rotating propellerscounter-rotating propellers/�kaυntə rəυ |�tetŋ prə|�peləz/ pluralnoun propellers which turn in oppositedirections (NOTE: They are also calledcontra-rotating propellers.)couplecouple /�k�p(ə)l/ noun two of some-thing � a couple of minutes two orthree minutes � verb 1. to connect or tojoin, often mechanically � The auxiliarypower unit is a self-contained unitwhich normally consists of a small gasturbine engine which is coupled to agearbox. 2. to combine � Pilot error,coupled with poor weather conditions,resulted in an accident.couplingcoupling /�k�plŋ/ noun a joining orconnecting component � When not inuse, the coupling is sealed by a dustcap.coursecourse /kɔ�s/ noun 1. an imaginaryline across the surface of the Earthwhich must be followed in order toarrive at the destination � to alter

course to change direction or to followa different route 2. a formal period ofstudy � a meteorology course 3. contin-uing time � in the course of the brief-ing during the briefingcourse correction

course correction /�kɔ�s kə |

�rekʃ(ə)n/ noun same as heading cor-rectioncourse deviation indicator

course deviation indicator /�kɔ�s�di�vi |�eʃ(ə)n �ndketə/ noun a nee-dle in an omni-bearing indicatorwhich indicates if an aircraft is on aselected course. Abbreviation CDIcover

cover /�k�və/ verb 1. to include e.g.the complete extent of a period of timeor the whole of a particular area � Therestriction covers the period from 4th-8th July. � the area covered by theforecast the area which the forecastdeals with 2. to deal with a subject, as ina text � The subject of central warningsystems is covered in the systems book.3. to be completely over something soas to hide what is underneath � The areais covered in snow. � noun somethingwhich goes over something else com-pletely � cloud cover the amount ofcloud � snow cover a situation in whichthere is a layer of snow on top of theearth so that the earth cannot be seencoverage

coverage /�k�v(ə)rd"/ noun 1. theamount of space or time given to a sub-ject, an event, etc. � More complete cov-erage of the one-in-sixty rule is given inthe plotting section of these notes. 2. thearea within which a radar unit candetect objects � glidepath coverage �

localiser coveragecowl

cowl /kaυl/ noun a covering usuallymade up of hinged or removable panels� cowl flap a removable or hinged panelof a cowl � Further cooling can beobtained by the use of controllable cowlflaps which regulate the amount of airflowing across the cylinders.cowling

cowling /�kaυlŋ/ noun a coveringusually made up of hinged or removablepanels � Access to the engine compart-ment is normally via hinged cowlingpanels.CPL

CPL abbreviation Commercial Pilot’sLicence


61 cross-pointer indicatorcrab

crab /kr�b/ noun a manoeuvre inwhich an aircraft is steered slightly intoa crosswind to compensate for flyingslightly off course � verb to steer an air-craft slightly into a crosswind to com-pensate for flying slightly off coursecraft

craft /krɑ�ft/ noun 1. a boat, etc., forcarrying people or goods on water 2. anaircraft or spacecraft for carrying peo-ple or goods in the air or in space � Anairship is classified as a lighter-than-air craft.crankcase

crankcase /�kr�ŋkkes/ noun thepart of the engine that houses the crank-shaft and also usually the oil pump � Oilpassages in the crankcase allow lubri-cating oil to pass through.crankshaft

crankshaft /�kr�ŋkʃɑ�ft/ noun thepart of a piston engine connecting thepistons, via the connecting rods, to theflywheel and gearbox � Rpm is thenumber of revolutions per minute thatthe engine crankshaft is making.crash

crash /kr�ʃ/ noun an accident thatcauses damage � verb to have an acci-dent or collision that causes damage �

The aircraft crashed into the sea.crash-divecrash-dive /�kr�ʃ dav/ verb tomove downwards quickly through theair front first and crash, or cause an air-craft to do thiscrash-land

crash-land /�kr�ʃ �l�nd/ verb toland heavily without using the under-carriage, so that the aircraft is damaged� The aircraft crash-landed short of therunway.crash-landing

crash-landing /�kr�ʃ �l�ndŋ/ nounan act of landing an aircraft heavily,sometimes without the undercarriage �

The crash-landing did not damage theaircraft as much as the pilot expected.create

create /kri|�et/ verb to make, to pro-duce � The velocity and pressure of theexhaust gas create the thrust in the tur-bojet engine.creep

creep /kri�p/ noun 1. a process ofweakening and slow damage to some-thing � Creep is a particular feature ofcomponents which are subjected tooperation at high temperatures. 2. aslight movement of a tyre on a wheelcaused by landing � Aligned white

marks on the wheel and tyre indicatethat there is no creep.crest

crest /krest/ noun the top of a moun-tain or wave � Wind speeds increasewith height, the speed of the wind at thecrest of a mountain or wave being thegreatest.crew

crew /kru�/ noun two or more peoplewho have responsibility for flight oper-ationscriteria

criteria /kra|�təriə/ � criterioncriterion

criterion /kra |�təriən/ noun a stand-ard by which you define, decide orjudge something (NOTE: The plural formis criteria.) � the criterion for promo-tion is seniority senior staff will be pro-moted firstcritical

critical /�krtk(ə)l/ adjective 1.extremely important, essential � Tem-perature and oil pressure are critical toany type of system. 2. at which animportant change occurs � As the angleof attack is increased, it reaches thecritical point when the airflow over theupper surface of the wing begins tobreak down.cross

cross /krɒs/ verb 1. to get from oneside of an area to another � to cross theAtlantic to go from one side of theAtlantic to the other 2. to go across eachother at an angle � Meridians intersectat the poles and cross the equator atright angles.cross-check

cross-check /�krɒs tʃek/ noun veri-fication, making certain � verb to verifyor make certain � Cross-check doorsclosed and locked and escape slidesarmed. (NOTE: This word is often usedin brief messages from one crew mem-ber to another, as from the pilot to cabinstaff, to confirm that an action has beencarried out.)cross-country

cross-country /�krɒs �k�ntri/ nouna flight during which the student pilotmust demonstrate navigation skills �

the qualifying cross-country flight forthe PPLcross-pointer indicator

cross-pointer indicator /�krɒs�pɔntə �ndketə/ noun a displaywith crossing horizontal and verticalbars to indicate aircraft position in rela-tion to the glideslope


cross-section 62cross-sectioncross-section /�krɒs �sekʃən/ nouna view of an object seen as if cutthrough � The diagram is a cross-sec-tion of a turbojet engine.crosswindcrosswind /�krɒswnd/ noun a sur-face wind which blows at an angle tothe landing or take-off heading � Onsome aircraft, crosswind take-offsshould be made with full aileron deflec-tion in the direction from which thewind is blowing.

COMMENT: A crosswind landing is oneof the most difficult exercises for astudent pilot. The final approach isusually made with the aircraft yawedinto wind, while tracking the extendedrunway centreline. Just beforetouchdown, the pilot aligns the aircraftwith the direction of flight using therudder pedals. Correct timing for thealignment and accurate airspeed arerequired to achieve positive contactwith the runway surface otherwise theaircraft may depart the runway to oneside.

crosswind componentcrosswind component /�krɒs |

�wnd kəm |�pəυnənt/ noun that part ofthe wind force acting at an angle to thedirection of flightcrosswind legcrosswind leg /�krɒswnd le$/noun part of the airfield traffic circuitflown at approximately 90° to the direc-tion of take off and climb out, followedby the downwind legCRTCRT /�si� ɑ� �ti�/ abbreviation cathoderay tubecruisecruise /kru�z/ noun the main part ofthe flight between top of climb aftertake-off and descent for landing � verbto fly the main part of the flight betweentop of climb after take-off and descentfor landing � We are cruising at 500 kt.� Cruising speed, cruising power andcruising altitude are selected to givemaximum engine efficiency and prolongengine life.cruising altitudecruising altitude /�kru�zŋ��lttju�d/, cruising level noun thealtitude at which most of a flight isflown en route to a destination, from topof climb to top of descent � Our cruis-ing altitude will be 35,000 feet.cruising powercruising power /�kru�zŋ �paυə/noun engine power used to give

required speed from top of climb to topof descent usually giving fuel economyand long engine life � Cruising power isabout 2,300 rpm.cruising speedcruising speed /�kru�zŋ spi�d/,cruise speed noun the speed selectedfrom top of climb to top of descent, usu-ally giving fuel economy and longengine life � The cruising speed is 110knots.cruising weightcruising weight /�kru�zŋ wet/noun the weight of an aircraft in flight,consisting of its weight when empty, theweight of its payload, and the weight ofthe fuel that it has leftcrushcrush /kr�ʃ/ verb to damage by pres-sure � Excessive load on the beam maycrush the core.crystalcrystal /�krstəl/ noun a regular geo-metric shape formed by minerals, or aswater freezesCSDUCSDU abbreviation constant speeddrive unitCSUCSU abbreviation constant speed unitCTACTA abbreviation control areaCTOTCTOT abbreviation calculated take-offtimeCTRCTR /kən |�trəυl/ abbreviation controlzonecubiccubic /�kju�bk/ adjective measuredin volume, by multiplying length, depthand width � cubic centimetres (cc) theusual unit used to measure the capacityof an internal-combustion engine � Theengine has a capacity of 2,000cc.Abbreviation cc � cubic foot, cubicinch, cubic metre, cubic yard the vol-ume of a cube whose edge measuresone foot, inch, metre or yard, respec-tivelycumuliformcumuliform /�kju�məlfɔ�m/ adjec-tive which develop vertically � cumuli-form clouds such as cumulonimbuscumulonimbuscumulonimbus /�kju�mjυləυ |

�nmbəs/ noun a dark, low cumulus –type of cloud associated with thunder-storms � A cumulonimbus has a charac-teristic anvil shape. Abbreviation CBcumuluscumulus /�kju�mjυləs/ noun big,fluffy, white or grey cloud heaped orpiled up, which develops at low altitude� Cumulus clouds may develop because


63 cylindrical

of thermal activity resulting from thewarming of the surface. � Grey cumulusoften develop into cumulonimbus. �

altocumulus, stratocumuluscumulus cloudcumulus cloud /�kju�mjυləsklaυd/ noun clouds which form only inan unstable atmosphere and, as thename suggests, often build vertically forgreat distances. Also called heap cloudcurrentcurrent /�k�rənt/ adjective present,actual, happening at the moment � cur-rent weather conditions presentweather conditions � current positionthe position now � noun 1. an electricalsupply � alternating current � directcurrent 2. flowcurvaturecurvature /�k%�vətʃə/ noun a curvedshape � curvature of the earth thecurving of the Earth’s surface due to thespherical form of the Earthcustomarycustomary /�k�stəməri/ adjectivenormal or usual � It is customary for thesenior cabin supervisor to introduceherself to passengers at the start of aflight.customscustoms /�k�stəmz/ noun an officialdepartment of government concernedwith movement of people and freightacross national borders � customs aer-odrome an aerodrome, usually near aborder or coast, with customs facilitiescustoms dutycustoms duty /�k�stəmz �dju�ti/noun same as import duty � the dutypayable on a carton of cigarettescyclecycle /�sak(ə)l/ noun a series ofactions which end at the same point asthey begin � With the piston engine, thecycle is intermittent, whereas in the gasturbine, each process is continuous. �life cycle of the thunderstorm cell the

process of formation, development anddecay of a thunderstormcycliccyclic /�sklk, �saklk/, cyclical/�sklk(ə)l/ adjective referring to orhappening in a cycle � Off-shore andon-shore wind patterns are cyclic.cyclonecyclone /�sakləυn/ noun a system ofwinds rotating inwards to an area of lowbarometric pressure � These areas oflow pressure are called hurricanes inthe Atlantic Ocean, cyclones in theIndian Ocean and Bay of Bengal, andtyphoons in the China Sea. Also calledlow, depressioncycloniccyclonic /sa|�klɒnk/ adjective refer-ring to air movement, which turns in thesame direction as the Earth and which,when seen from above, is anticlockwisein the northern hemisphere and clock-wise in the southern hemisphere � Inwinter the sub-tropical high retreatsand gives way to cyclonic pressure pat-terns which produce cool unsettled con-ditions with rain at times.cylindercylinder /�slndə/ noun a deviceshaped like a tube, in which a pistonmoves � Smaller aircraft have a statichydraulic system similar to a car, with amaster cylinder and individual brakecylinders at each wheel. � cylinderblock the casing containing the cylin-ders in a internal combustion engine �cylinder head the removable top part ofa piston engine cylinder containingplugs, inlet and exhaust connectionsand valvescylindricalcylindrical /s|�lndrk(ə)l/ adjectivewith the shape of a cylinder � The mod-ern jet engine is basically cylindrical inshape.


DDD abbreviation danger areaDADA abbreviation danger areaDAAISDAAIS abbreviation danger area activ-ity information serviceDACSDACS abbreviation danger area cross-ing serviceDADCDADC abbreviation digital air datacomputerDADSDADS abbreviation digital air data sys-temDALRDALR abbreviation dry adiabatic lapseratedamagedamage /�d�md"/ noun harm that iscaused to something � If the tempera-ture rises it can cause serious damageto the engine. � verb to cause harm tosomething � Small stones around therun-up area may damage propellers.damage tolerancedamage tolerance /�d�md"�tɒlərəns/ noun the ability of a materialor structure to withstand or resist dam-age � The structural efficiency ofbonded and machined structure is notachieved at the expense of damage tol-erance.dampendampen /�d�mpən/ verb 1. todecrease or reduce � An accumulator isfitted to store hydraulic fluid underpressure and dampen pressure fluctua-tions. 2. to make slightly wetdamperdamper /�d�mpə/ noun a device todecrease or reduce something � A yawdamper is used for rudder control.D & DD & D abbreviation distress and diver-sion celldanger areadanger area /�dend"ə �eəriə/ nounairspace of a particular length, widthand depth, within which at particulartimes there may be activities which are

dangerous to the flight of the aircraft.Abbreviation D, DAdanger zonedanger zone /�dend"ə zəυn/ nounan area where danger existsdatadata /�detə/ noun 1. informationmade up of numbers, characters andsymbols often stored on a computer insuch a way that it can be processed �

Airspeed information is supplied froman air data computer. � meteorologicaldata information about weather condi-tions stored on a computer 2. informa-tion. � recorderdatumdatum /�detəm/ noun a reference orbase point of a scale or measurement,e.g. mean sea leveldatum shift trim systemdatum shift trim system /�detəmʃft �trm �sstəm/ noun a trim systemwhich varies the incidence of an all-moving tailplane without moving thecockpit controls � In some aircraft, thedatum shift is operated automatically.dBdB abbreviation decibelDCDC abbreviation direct currentDCLDCL abbreviation departure clearancede-de- /di�/ prefix undo, remove or stop �

deactivate � depressurisedeactivatedeactivate /di� |��ktvet/ verb toturn off a system or a piece of equip-ment thus stopping it being ready tooperate � On some aircraft nose wheelsteering must be deactivated prior toretraction.dead reckoningdead reckoning /�ded �rekənŋ/,ded reckoning noun navigation usingcalculations based on airspeed, course,heading, wind direction and speed,ground speed, and time � In the earlystages of practical navigation, the stu-dent pilot navigates by using dead reck-


65 deck

oning. Abbreviation DR (NOTE: Theterm comes from ‘deduced’ reckoningor ‘ded’ reckoning.)de-aerate

de-aerate /�di� �eərəet/ verb toremove gas, especially carbon dioxideor air, from a liquid such as fuel � Thepump helps to de-aerate the fuel beforeit enters the engine.de-aerationde-aeration /�di� eə |�reʃ(ə)n/ nounthe process of removing gas from a liq-uid such as fuel � Partial de-aeration offuel takes place in the pump.de-aeratorde-aerator /�di� eə |�retə/ noun adevice to remove gas from a liquidde-aerator tray

de-aerator tray /�di� eə |�retə �tre/noun a device in the lubrication systemto remove air bubbles from oildeal

deal /di�l/ noun � a great deal a largeamount of, a lot of � A great deal ofdamage was done to the aircraft as aresult of the fire. � verb to handle ormanage � A computer can deal with theconstant inputs required to control anunstable aircraft.debris

debris /�debri�/ noun scattered brokenpieces � Before running up the engine,check that the aircraft is on firm groundand that the area is free of stones andother debris. � The aircraft exploded inmid-air, spreading debris over a widearea of the countryside.decaldecal /d|�k�l/ noun picture, letters ordigits printed on adhesive paper, whichis transferred onto a surface and may bepeeled away � A red decal with AVGAS100LL in white letters indicates the typeof fuel to be used.decelerate

decelerate /di� |�seləret/ verb to slowdown � Reverse thrust and brakes helpto decelerate the aircraft after landing.Opposite acceleratedecelerationdeceleration /di� |�selə |�reʃ(ə)n/noun slowing down � Anti-skid brakingsystems units are designed to preventthe brakes locking the wheels duringlanding, thus reducing the possibility ofwheel skid caused by the sudden decel-eration of the wheel. Opposite acceler-ationdecibel

decibel /�desbel/ noun a unit formeasuring the loudness of a sound.Abbreviation dB

decimal

decimal /�desm(ə)l/ noun a decimalfraction � adjective � decimal fractiona fraction as expressed in the decimalsystem � 0.50 is a decimal fraction thatis equal to 1/2. � correct to threeplaces of decimal or to three decimalplaces correct to three figures after thedecimal point � 2.754 is correct to threedecimal places, 2.7 is correct to onedecimal place.decimal notation

decimal notation /�desm(ə)l nəυ|

�teʃ(ə)n/ noun the method of writing anumber in the decimal system � Thefraction 3/4 can be written as 0.75 indecimal notation. � Prices and numberare normally written using decimalnotation. � He finds it difficult to under-stand how the computer works becauseit uses binary not decimal notation.decimal place

decimal place /�desm(ə)l �ples/noun the position of a number to theright of the decimal pointdecimal point

decimal point /�desm(ə)l �pɔnt/noun the dot (.) used to separate a wholenumber from a decimal fraction

COMMENT: The decimal point is usedin the USA and Britain. In mostEuropean countries a comma (,) isused to show the decimal, so 4,75% inGermany is written 4.75% in Britain.

decimal system

decimal system /�desm(ə)l�sstəm/ noun system of countingbased on the number 10 and using thedigits 0 – 9decision

decision /d |�s"(ə)n/ noun the act ofdeciding or of making up one’s mind �to make a decision to choose a courseof action � The decision to evacuate theaircraft was made by the captain.decision height

decision height /d |�s"(ə)n hat/noun the altitude at which, during anILS landing approach, a pilot mustdecide whether to land or carry out amissed approach � The pilot waiteduntil she was at decision height beforeinitiating the missed approach proce-dure. Abbreviation DH

COMMENT: An ILS approach generallyhas a decision height of 200 ft (60 m)above ground level.

deck

deck /dek/ noun the floor of a ship oraircraft


decode 66decode

decode /di� |�kəυd/ verb to changecoded information into readable form �

Incorrectly spaced information pulsescan result in failure by the ground sta-tion to decode the aircraft information.decoder

decoder /di�|�kəυdə/ noun a deviceused to decode signals from the air traf-fic control radar beacon system � Theaircraft receiver is set to the requiredfrequency and linked to a selective callsystem decoder which has a 4-lettercode.decrease

decrease noun /�di�kri�s/ a lesseningor reduction � A decrease in powerresults in the aircraft descending. �

verb /d |�kri�s/ to become less, to fall �

Air density and pressure decrease withan increase in altitude. � opposite (allsenses) increasededuce

deduce /d|�dju�s/ verb to work some-thing out in the mind using informationprovided � Sometimes, it is possible toestimate the depth of the layer of mist orfog from the ground observations andhence to deduce the ground range fromany height.defect

defect /�di�fekt/ noun a fault or error� Low oil pressure or excessive temper-ature indicate the development of a pos-sible defect.defective

defective /d |�fektv/ adjective faultyor not operating correctly � Loss of sup-ply pressure is caused by either a defec-tive booster pump or lack of fuel.define

define /d |�fan/ verb 1. to give anexact explanation, as in a dictionary � itis not easy to define the word it is dif-ficult to say exactly what the wordmeans 2. to set the limits of something� Cloud tops are very difficult to define.definite

definite /�def(ə)nət/ adjective refer-ring to something which is not in doubt,which is certain � Using a time scale onthe track, the pilot should be preparedto look for a definite feature at a definitetime. Opposite indefinitedefinition

definition /�def |�nʃ(ə)n/ noun anexact explanation of what a word orexpression means � The definition of ayear is the time taken for a planet todescribe one orbit around the sun. � bydefinition understood by the use of the

word itself � A sphere is, by definition,round.deflatedeflate /di�|�flet/ verb to allow air toescape from something, so that itbecomes smaller or collapses. Oppositeinflate � to deflate a tyre to allow theair to escape from a tyredeflationdeflation /di� |�fleʃ(ə)n/ noun the actof allowing air to escape from some-thing, so that it becomes smaller or col-lapses � Deflation of a tyre is done bydepressing the valve.deflectdeflect /d |�flekt/ verb 1. to cause anobject to move away from a neutral orcentral position � During an out-of-bal-ance turn, the ball in the slip indicatorwill be deflected to the left or right. 2. tomove a moving object, gas or liquidaway from its intended path � In anopen-cockpit aircraft, the windshielddeflects the airflow over the pilot’shead.deflectiondeflection /d|�flekʃ(ə)n/ noun 1.movement away from a central or neu-tral position � Full deflection of theailerons is sometimes needed on take-off to counteract a crosswind. 2. themovement of a moving object, gas orliquid away from its intended path � Inthe southern hemisphere the deflectionof wind at the equator is to the left.deformationdeformation /�di�fɔ�|�meʃ(ə)n/noun a change of the correct shapecaused by stress � Deformation of wingpanels may be an indication of seriousstructural damage.degdeg abbreviation degreedegradationdegradation /�de$rə |�deʃ(ə)n/ nouna decrease in quality � Degradation ofthe radio signal sometimes makes itimpossible to understand the message.degradedegrade /d |�$red/ verb to decreasethe quality of something � Interferingsignals degrade VOR performance.degreedegree /d|�$ri�/ noun 1. a level,amount or quantity � the degree ofcompression the amount of compres-sion � a high degree of safety a highlevel of safety � to a greater degreemore than � to a lesser degree less than2. a unit of temperature � twentydegrees Celsius (20°C) � twentydegrees Centigrade (20°C) � seventy


67 density altitude

degrees Fahrenheit (70°F) 3. a unit ofmeasurement of an angle equal to1/360th of a circle – each degree isdivided into 60 minutes and each min-utes into 60 seconds � Make a turn tothe right at a bank angle of 30°. � anangle of 90° a right angle 4. a unit ofdirection as measured on a compass �

east = 090° � west = 270°degrees truedegrees true /d|�$ri�z �tru�/ noundegrees of direction measured from truenorth, not magnetic north. Also calledtrue degrees. Symbol °Tdehydrationdehydration /�di�ha|�dreʃ(ə)n/noun an unwanted and sometimes dan-gerous loss of water from the body �

Dehydration can be avoided by drink-ing plenty of water.de-icede-ice /�di� �as/ verb to remove ice �

The ground crew de-iced the aircraftprior to take-off.de-icerde-icer /�di� �asə/ noun a device orsubstance used to remove ice � De-icerspray should be checked to make sure itis not harmful to light aircraft wind-screens.de-icingde-icing /�di� �asŋ/ noun theremoval of ice � adjective referring tothe removal of ice � de-icing fluid �

anti-icing, icingdelaydelay /d|�le/ noun a period after theexpected time that you have to waitbefore something happens, the length oftime by which something is late � Byday, the presence of cloud can cause adelay in clearance of fog. � verb 1. tomake late, to cause to be late � Take-offwas delayed because of fog. 2. to putsomething off until later � He delayedtelling her the news until they hadlanded.delayed-actiondelayed-action /d |�led ��kʃən/adjective in which there is an unusualpassing of time between stimulus andresponse � The door is fitted with adelayed-action lock which operates oneminute after the power has beenswitched off.deliverdeliver /d |�lvə/ verb to provide, togive � The motor will continue to runbut will deliver only one-third the ratedpower. � The pump can deliver fuel atthe rate of 2,000 gph.

deliverydelivery /d|�lv(ə)ri/ noun the act ofproviding or giving � On some pumps, adepressurising valve is used to blockdelivery to the system.delivery pressuredelivery pressure /d|�lv(ə)ri�preʃə/ noun the pressure normallyexpected when fuel is being pumpeddelugedeluge /�delju�d"/ noun � fire delugesystemdemanddemand /d|�mɑ�nd/ noun 1. a need oruse caused by necessity � high currentdemand on a generator a situationrequiring the generator to produce a lotof electricity 2. a request which is madefirmly � on demand when asked for orordered � A computer will produce, ondemand, a flight plan giving the opti-mum route, levels and fuel. � verb 1. torequire as a necessity � Higher operat-ing weights of modern aircraft demandan increase in the number of wheels fit-ted to the landing gear. 2. to ask firmly� He demanded an explanation.demonstratedemonstrate /�demənstret/ verb toshow by clear example or explanation �Torricelli first demonstrated that theatmosphere has weight. � It will bedemonstrated in chapter 12 that turbu-lence is associated with strong winds.demonstrationdemonstration /�demən |�streʃ(ə)n/noun a clear, often visual, description orexplanation � Your instructor will give ademonstration of the stall-recoverytechnique.densedense /dens/ adjective 1. referring toa substance which is closely compacted� dense fog thick fog 2. referring to theamount of mass of a substance for agiven unit of volume � Air which con-tains water vapour is less dense than airwhich does not.densitydensity /�densti/ noun a quantity ofmass for a given unit of volume � airdensitydensity altitudedensity altitude /�densəti��lttju�d/ noun the pressure altitudecorrected for non-ISA temperature

COMMENT: Density altitude is a veryimportant factor in calculating aircraftperformance because of its effect onengine performance, time to reachtakeoff speed (and therefore length oftake-off run) and rate of climb.


density error 68density errordensity error /�densəti �erə/ noun acorrection to airspeed to give true air-speedDEPDEP abbreviation departure messagedepartdepart /d|�pɑ�t/ verb to leave � Theflight departs at 0200 GMT. Oppositearrivedepartmentdepartment /d|�pɑ�tmənt/ noun aseparate part of a complex whole, espe-cially of an organisationdeparturedeparture /d |�pɑ�tʃə/ noun 1. the actof leaving � departure time the timewhen an aircraft becomes airborne 2.the distance between two meridians atany given latitudedeparture loungedeparture lounge /d |�pɑ�tʃəlaυnd"/ noun a room at an airportwhere passengers wait to board theiraircraftdeparture pointdeparture point /d|�pɑ�tʃə pɔnt/noun a place on the map representingthe place from which a flight beginsdeparturesdepartures /d |�pɑ�tʃəz/ noun thepart of an airport that deals with passen-gers who are leavingdependdepend /d |�pend/ verb 1. to be con-trolled or affected entirely by some-thing � Whether or not an object can beseen by aircrew at a given distance willdepend on factors such as size, shapeand colour of the object. � If an aircraftditches in the sea, early rescue dependson rapid location of survivors. 2. to relyon � Pilots depend on air traffic con-trollers to help them conduct a safeflight.dependabledependable /d |�pendəb(ə)l/ adjec-tive reliable, trustworthy � Mercurybarometers have largely been replacedby precision aneroid barometers whichare smaller, simpler to use, and moredependable.dependentdependent /d|�pendənt/ adjectiverelying on or unable to do withoutsomething � The height indicated by analtimeter is dependent on the pressurewhich is set on the sub-scale.deploydeploy /d|�plɔ/ verb to come intoaction, to become ready to be used �

Slide rafts are door-mounted and auto-matically deploy and inflate when thedoor is opened in the armed position.

deposit

deposit /d|�pɒzt/ noun a layer ofcollected matter on a surface � Adeposit of ice crystals causes the air-craft surfaces to change their aerody-namic characteristics. � Wheel brakesshould be inspected for snow or icedeposits.depreciate

depreciate /d |�pri�ʃiet/ verb todecrease in value � The aircraft depre-ciated by 100% over the 5 year period.Opposite appreciatedepreciation

depreciation /d|�pri�ʃi|�eʃ(ə)n/noun a decrease in value � There was adepreciation of 100% in the value of theaircraft over the 5 year period. Oppo-site appreciationdepress

depress /d|�pres/ verb to push down� Switches on the control columnsinstantly disengage the autopilot whendepressed.depression

depression /d|�preʃ(ə)n/ noun 1. anarea of low atmospheric pressure � Inthe northern hemisphere, the windblows anticlockwise round a depressionand clockwise round an anticyclone andvice versa in the southern hemisphere. �deep depression area of very low rela-tive atmospheric pressure 2. a lowerarea on a surface, which is often diffi-cult to see � A depression on the wingsurface must be investigated in case it isan indication of more serious structuraldamage.depressurisation

depressurisation /di� |�preʃəra |

�zeʃ(ə)n/, depressurization noun aloss, especially sudden, of cabin pres-sure � Emergency oxygen must be avail-able in the event of depressurisation.depressurise

depressurise /di� |�preʃəraz/,depressurize verb to lose pressuresuddenly, or to cause to lose pressure �

The aircraft began to depressurise at20,000 feet.depth

depth /depθ/ noun the distance fromthe top surface of something to the bot-tom � The troposphere’s depth is varia-ble in temperate latitudes.derive

derive /d |�rav/ verb to get or to obtain� Performance data is derived fromflight tests. � Kepler derived the lawswhich relate to the motion of planets intheir orbits.


69 detachable wheel spatsdescend

descend /d |�send/ verb to lose alti-tude, usually in a planned manoeuvre �the aircraft descended to 10,000 feetthe pilot reduced altitude until the air-craft was at 10,000 feet. Oppositeclimb, ascenddescent

descent /d|�sent/ noun a planned lossof altitude � The descent from cruisealtitude took 40 minutes. � in thedescent during planned loss of altitude,usually in preparation for landing

‘…a search of radar recordings showedthat a DC-10 had tracked within a fewhundred metres of the house whilepassing 9,500 feet in the descent toGatwick’ [Pilot]

describe

describe /d |�skrab/ verb 1. to givethe particular features of something � todescribe what happened put intowords exactly what happened 2. to drawa geometric figure or to move in a linethat forms a geometric figure � The def-inition of a year is the time taken for aplanet to describe one orbit around thesun. � to describe an arc to draw ormove in an arcdescription

description /d |�skrpʃən/ noun 1.the act of giving the particular featuresof something � a detailed description ofworld climate 2. the drawing or makingof a geometric figure � the descriptionof a triangle the drawing of a triangledesert

desert /�dezət/ noun a large area ofdry often sandy country � Over desertareas the lack of water vapour producescold nights.design

design /d |�zan/ noun a plan or draw-ing of something before it is made � Thedesign and testing of aircraft are impor-tant stages in the development pro-gramme. � verb to draw plans usingaccurate information in preparation forconstructing something � to design anaircraft to have the idea, make draw-ings, calculate data, etc., with the inten-tion of producing an aircraftdesignate

designate /�dez$net/ verb tochoose for a special purpose � Thisregion is designated as a fire zone.designator

designator /�dez$netə/ noun agroup of letters and/or numbers thatidentify something

designerdesigner /d |�zanə/ noun a personwho has the idea for, and makes plans toproduce, something � Rutan is adesigner of unusual-looking aircraft.

‘…test-pilot’s tip for a safe first flight –take the designer with you’ [FlightInternational 9–15 Oct. 1996]

desirabledesirable /d|�zaərəb(ə)l/ adjectivepreferred or wanted � Equalisation ofthe air pressure across the eardrum ismore difficult to achieve duringdescents than ascents, and a minimumrate of pressure change is desirable.despitedespite /d |�spat/ preposition in spiteof � Many beacons and aids which areprovided for low operations are left outto keep the chart clear – despite this, thecharts still look very difficult to under-stand. � despite the weather, we tookoff although the weather was bad, wetook offDESTDEST abbreviation destinationdestinationdestination /�dest|�neʃ(ə)n/ nounthe place to which somebody or some-thing is going � Aerodrome forecastsare normally given in code form fordestination and alternates.destroydestroy /d|�strɔ/ verb to damage somuch as to make useless � The aircraftwas destroyed in the accident.destructiondestruction /d|�str�kʃən/ noun anact or instance of making completelyuseless by breaking � By testingselected parts to destruction, a safe lifecan be assessed for all structures andcomponents.destructivedestructive /d|�str�ktv/ adjectivereferring to something which destroys �the winds of a tornado are extremelydestructive tornadoes cause a lot ofserious damagedetachdetach /d |�t�tʃ/ verb to remove a partfrom something, or to be removed � Afuselage panel became detached andhad to be replaced. � The parachuteflare is a device which is fired to aheight of 1,200 ft where a red flare andparachute detach.detachabledetachable /d |�t�tʃəb(ə)l/ adjectivereferring to something which can beunfixed and removeddetachable wheel spatsdetachable wheel spats /d|

�t�tʃəb(ə)l �wi�l �sp�ts/ plural noun


detail 70

streamlined coverings for the wheels oflight aircraft which can be taken off toallow inspection and repairs of tyresdetaildetail /�di�tel/ noun the important andless important facts about something �

The amount of detail which appears ona topographical chart depends upon thescale.detectdetect /d|�tekt/ verb to discover thepresence of something � Apart fromsensing the abnormal rate of descent ofa false glide slope, the pilot can detectan error by comparing height with dis-tance to go.detectiondetection /d|�tekʃən/ noun the dis-covery of the presence of somethingdetectordetector /d |�tektə/ noun a device fordiscovering the existence of something� ice detector a device for detecting thepresence of ice on the airframe � Whenice forms on the vibrating rod ice detec-tor head, the probe frequencydecreases.deterioratedeteriorate /d|�təriəret/ verb tobecome or make bad or worse � Theelectrolyte in the cells of a nickel-cad-mium battery does not chemically reactwith the plates and so the plates do notdeteriorate. � deteriorating weatherworsening weatherdeteriorationdeterioration /d|�təriə|�reʃ(ə)n/noun worsening � a deterioration inthe situation a worsening of the situa-tiondeterminationdetermination /d|�t%�m|�neʃ(ə)n/noun 1. the act of finding out by calcu-lation � Structure design for a givensafe life has led to the determination ofthe minimum number of flying hourswhich should pass before major failureoccurs. 2. the strength of mind to dowhat is required � Determination was amajor factor in the trainee passing hisexams.determinedetermine /d |�t%�mn/ verb 1. to findout by calculation � To determine theaverage age, divide the total number ofyears by the number of people. � Whenwe wish to fly from one place to another,it is first necessary to determine thedirection of the destination from thedeparture point. 2. to set or to fix pre-cisely � On a large transport aircraft,

the safety of hundreds of passengers isinvolved, and regulations determine theminimum crew that must be carried.detonation

detonation /�detə |�neʃ(ə)n/ noun asudden, explosive burning of theair/fuel mixture � Prior to the accident,engine detonation could be heard bypeople on the ground.

COMMENT: Detonation imposesexcessive loads on the pistons andother engine components, possiblycausing engine damage and resultingin engine failure.

develop

develop /d|�veləp/ verb 1. to comeinto being � Carburettor icing maydevelop in any type of carburettor inrelatively warm air temperatures. �

Vertical motion and therefore turbu-lence suggest that thunderstorms maydevelop. 2. to get bigger, to grow andchange � During the day, light breezesmay develop into strong winds.development

development /d|�veləpmənt/ noun1. something new, made as an improve-ment on something older � Satellitenavigation aids for light aircraft are arecent development. 2. growth andchange � To study weather and itsdevelopment, the meteorologist has tobe aware of the horizontal changes inatmospheric pressure both in space andtime.deviate

deviate /�di�viet/ verb to move awayfrom the normal position or path � If theaircraft deviates beyond the normal ILSglide slope, the flight crew are alerted.deviation

deviation /�di�vi|�eʃ(ə)n/ noun 1. theprocess of moving away from the nor-mal position or path � On finalapproach, any deviation from theextended centreline of the runwayshould be corrected immediately. 2. amagnetic compass error in a particularaircraft caused by magnetic influencesin the structure and equipment of theaircraft itself � Deviation is not a con-stant value but varies from one aircraftto another.device

device /d |�vas/ noun an object, espe-cially mechanical or electrical, whichhas been made for a particular purpose� A capacitor is a device with the abilityto temporarily store an electric charge.


71 diffusiondewdew /dju�/ noun drops of condensedmoisture left on the ground overnight incool placesdew pointdew point /�dju� pɔnt/ noun thetemperature at which air is saturatedwith water vapour and condensationbegins

COMMENT: Weather reports usuallyinclude the air temperature and dewpoint temperature. When thedifference between temperature anddew point is small, there is a strongpossibility of fog, clouds, orprecipitation.

DFDF abbreviation direction findingDFDRDFDR abbreviation digital flight datarecorderDFRDFR abbreviation departure flow regu-lationDFTIDFTI abbreviation Distance fromtouchdown indicatorDHDH abbreviation decision heightDIDI abbreviation direction indicatordiagonaldiagonal /da|��$ən(ə)l/ adjective 1.joining two opposite corners of a rec-tangle 2. sloping halfway between thevertical and horizontal � Early aircraftwere of the wire braced type of con-struction, the wire being superseded bytubular diagonal struts. � noun a linejoining two opposite corners of a rec-tanglediagramdiagram /�daə$r�m/ noun an oftensimplified drawing showing the struc-ture or workings of something � Thediagram shows a simple open-circuitsystem.diagrammaticdiagrammatic /�daə$rə |�m�tk/adjective referring to something whichis shown as a drawing of a system orstructure � diagrammatic format inthe form of a diagramdialdial /�daəl/ noun the face of an instru-ment showing a scale � A cup anemom-eter is connected to an instrument witha dial showing wind speed in knots.diameterdiameter /da|��mtə/ noun the dis-tance from one side of a circle to theother, passing through the centre �equatorial diameter the distance fromthe equator, through the centre of theEarth to the equator on the opposite sideof the globe

diaphragmdiaphragm /�daəfr�m/ noun a thinsheet of material used to separate partsor chambers � Some switches are oper-ated by a diaphragm which flexes underfluid or air pressure.differdiffer /�dfə/ verb to be unlike � Trackand heading differ by the amount ofdrift. � Because the chart time and thedeparture/arrival times differ, it is nec-essary to consider the movement of anyweather system which might affect theroute.differentialdifferential /�dfə |�renʃəl/ adjectivereferring to things which react differ-ently when measured against a norm orstandard � differential heating of theatmosphere the heating of the atmos-phere to varying temperatures depend-ing on the relative warmth of the land atthe equator and the polesdifferential expansion switchdifferential expansion switch/�dfərenʃəl k |�sp�nʃ(ə)n �swtʃ/noun a switch which operates on theprinciple that the coefficients of expan-sion of dissimilar metals are differentdifferentiatedifferentiate /�dfə|�renʃiet/ verb torecognise the difference between twothings; to show two things to be differ-ent � Some types of colour blindnessmake the sufferer unable to differentiatebetween blue and red.diffractiondiffraction /d|�fr�kʃ(ə)n/ noun thebreaking down of a beam of radiation �Diffraction produces a surface wavewhich follows the curvature of theearth.diffusediffuse /d|�fju�s/ adjective spread outin every direction � Glare caused by dif-fuse reflection of sunlight from the topof a layer of fog or haze can seriouslyreduce air-to-ground visibility. � verb tospread out in every direction � Light dif-fuses as it passes through fog.diffuserdiffuser /d |�fju�zə/ noun a device in ajet engine that alters the direction offlow of the air entering the engine aspart of the process of compressing itbefore it reaches the combustion cham-berdiffusiondiffusion /d |�fju�"(ə)n/ noun theprocess of spreading out � Gas from theturbine enters the exhaust system athigh velocities but, because of high fric-


digit 72

tion losses, the speed of flow isdecreased by diffusion.digit

digit /�dd"t/ noun any number from0 to 9 � Information is provided in afour-digit group.digital

digital /�dd"t(ə)l/ adjective referringto a system or device which uses signalsor information in the form of numbersdihedral

dihedral /da |�hedr(ə)l/ noun theangle between an upward sloping air-craft wing and a horizontal linediluted

diluted /da|�lu�td/ adjective madeweaker by adding water or some otherfluid � Spillage from a lead acid batterymay be neutralised by washing with adiluted solution of sodium bicarbonate.diluter

diluter /da |�lu�tə/ noun a device fordecreasing the strength or concentrationof a liquid or gas � Most flight decks usethe diluter demand system in which theoxygen is diluted with cabin air.dimension

dimension /da |�menʃən/ noun ameasurable distance such as height,length, etc., or a measurement of height,length, etc. � Variations of atmosphericpressure produce changes in the dimen-sion of the capsule chamber.diminish

diminish /d|�mnʃ/ verb to decreaseor to reduce in size or importance �

Friction is greatest near the ground anddiminishes with height. � At higher alti-tudes, ground objects are less easilyseen because of diminished size.diode

diode /�daəυd/ noun an electroniccomponent that allows an electrical cur-rent to pass in one direction and not theotherdioxide

dioxide /da|�ɒksad/ noun an oxidecontaining two atoms of oxygen. � car-bon dioxidedip

dip to move e.g. the wing or nose of anaircraft so that it points downwardsdirect

direct /da |�rekt/ adjective 1. in astraight line; by the shortest route � adirect flight 2. complete � the directopposite � verb to guide or control themovement of something � Clamshelldoors are hydraulically or pneumati-cally opened, and direct the exhaustgases forwards to produce reversethrust.

direct currentdirect current /da |�rekt �k�rənt/noun an electric current flowing in onedirection only � An electric starter isusually a direct current electric motorcoupled to the engine, which automati-cally disengages after the engine starts.Abbreviation DCdirectiondirection /da |�rekʃən/ noun thecourse taken by somebody or some-thing � The Earth rotates about its ownaxis in an anticlockwise direction.directionaldirectional /da|�rekʃən(ə)l/ adjec-tive referring to the course taken bysomebody or somethingdirectional gyrodirectional gyro /da|�rekʃ(ə)n(ə)l�d"arəυ/ noun a gyroscopic instrumentwhich indicates direction but does nothave a north-seeking magnet � Thedirectional gyro should be set to corre-spond with the magnetic compass. �

heading indicatordirectional radar beamdirectional radar beam /da |

�rekʃ(ə)n(ə)l �redɑ� �bi�m/ noun a sig-nal from a directional beacon enablingthe pilot to determine a bearing from thebeacon with a communications receiverdirection indicatordirection indicator /da|�rekʃən�ndketə/ noun an instrument whichgives direction information. Abbrevia-tion DIdirectivedirective /da|�rektv/ adjective refer-ring to the ability of a device to send orreceive signals in straight lines � Theantenna is highly directive in transmis-sion and reception. � noun general ordetailed instructions from managementto staff to guide them in their work �

According to the management directive,all late arrivals should be logged.directordirector /da|�rektə/ noun 1. a devicewith a central controlling function �

EFIS is a highly sophisticated type offlight director system. 2. a person whois a member of the board that controlsthe activities of a company � managingdirectordisadvantagedisadvantage /�dsəd |�vɑ�ntd"/noun an unwanted situation or condi-tion, or a factor which makes somebodyor something less likely to succeed �

The disadvantage of a booster pump isthat the output is constant so that whenengine demand is high, fuel pressure


73 dispense

tends to be low and vice versa. Oppositeadvantagedisadvantaged

disadvantaged /�dsəd |�vɑ�ntd"d/adjective � physically disadvantaged(person) a person who has a physicaldisability

COMMENT: The word ‘disadvantaged’may be regarded by some people as apolitically correct term for ‘disabled’.With the help of specially-adaptedcontrols, more and more disabledpeople are learning to fly.

disappear

disappear /�dsə|�pə/ verb 1. to van-ish � If air blew at right angles to iso-bars, the horizontal pressure differ-ences would eventually disappear. 2. topass out of sight � The aircraft took off,climbed out and soon disappeared fromview.disarm

disarm /ds|�ɑ�m/ verb 1. to switch offan active or live system � On the groundapproaching the terminal, the flightdeck will instruct the cabin crew to dis-arm the escape devices. 2. to forciblyremove a weapon from somebody � Thehijacker was disarmed by securityforces.disc

disc /dsk/ noun a circular flat plate �

A turbine consists of a disc on which ismounted a number of blades.discharge

discharge /ds |�tʃɑ�d"/ noun arelease of power from a source such asa battery � A lightning flash is a large-scale example of an electrical spark, ordischarge. � battery discharge the lossor release of electrical supply from abattery � verb to release electrical sup-ply from a source such as a battery �

The battery discharged overnight.disconnect

disconnect /�dskə |�nekt/ verb toseparate two things attached to oneanother � The electrical supply can bedisconnected by pulling out the plug.discrimination

discrimination /d|�skrm |

�neʃ(ə)n/ noun the ability to know orsee the difference between two similarthings � Targets on the same bearingwhich are separated radially by lessthan half a pulse length distance willappear at the receiver as one echo, sogood target discrimination requiresshort pulses.

discussdiscuss /d|�sk�s/ verb to write aboutor talk about a subject � This chapterwill discuss HF and VHF voice commu-nications.disembarkdisembark /�dsm |�bɑ�k/ verb toleave the aircraft after landing � Thepassengers finally disembarked at20.00 hours.disembarkationdisembarkation /�dsmbɑ�|

�keʃ(ə)n/ noun the act of leaving theaircraft after landing � The exits areused as conventional doors for disem-barkation.disengagedisengage /�dsn |�$ed"/ verb toswitch off a system or device � Switcheson the control columns instantly disen-gage the autopilot when depressed.dishdish /dʃ/ noun a shallow container forfooddish antennadish antenna /�dʃ �n |�tenə/ noun acircular antenna with a shape like ashallow bowldisintegrationdisintegration /ds |�nt |�$reʃ(ə)n/noun the falling apart or destruction ofsomething � Electromagnetic radia-tions resulting from the disintegrationof radioactive materials are known asgamma rays.dismantledismantle /ds |�m�nt(ə)l/ verb totake apart into single components � Onetype of inspection is able to revealfatigue cracks, corrosion, internal dam-age, the presence of loose articles andmercury spillage without the need todismantle the aircraft. Oppositeassemble (NOTE: The verb ‘mantle’ isnot used.)disorientationdisorientation /�dsɔ�riən|�teʃ(ə)n/noun a state of confusion in which thereis loss of understanding of where one isor which direction one is facing, etc. �

When the cabin is rapidly and com-pletely filled by smoke and fumes pas-sengers will suffer from disorientation.dispensationdispensation /�dspen|�seʃ(ə)n/noun permission not to have to dosomething � At very high altitudes theflying pilot must be on oxygen at alltimes, unless an aircraft dispensationhas been obtained.dispensedispense /d|�spens/, dispense withverb not to include or not to use some-thing � In some cases the rivets are dis-


dispersal 74

pensed with and the skin is fixed to theinternal members by the redux process.dispersaldispersal /d |�sp%�s(ə)l/ noun 1. theact of leaving an area and going in dif-ferent directions � the dispersal of acrowd the disappearance of a crowd 2.the clearing away of something such asmist, e.g. by the wind � the dispersal ofhill fog � Dispersal of cloud takes placewhen surface heating lifts the cloudbase or drier air is advected.dispersedisperse /d |�sp%�s/ verb 1. to leave anarea going in different directions � thecrowd dispersed the people in thecrowd left the area, going in differentdirections, so that eventually the crowddisappeared 2. to clear away � The fluo-rescent green dye will disperse slowly ina calm sea but quickly in a moderate torough sea.displacedisplace /ds |�ples/ verb to movesomething out of its normal position �

The atmosphere is said to be stable if,when a parcel of air is displaced verti-cally, it tends to return to its originallevel.displacementdisplacement /ds |�plesmənt/ nounmovement away from the normal posi-tion � The ILS is a cross-pointer indica-tor which shows the aircraft horizontaldisplacement from the localiser andvertical displacement from the glidepath.displaydisplay /d|�sple/ noun 1. the appear-ance of information on a monitor screenor on the panel of an instrument or of anindicator � There are three differenttypes of electronic display systems:EFIS, EICAS and ECAM. � digital dis-play information shown as numbers �

The clock uses a digital display to showthe time of 12:33. 2. a show or demon-stration � verb to show, e.g. on a panelor a screen � Alerting and warninginformation is displayed.disseminatedisseminate /d |�semnet/ verb tosend out or spread � Meteorologicalstations make routine weather observa-tions at fixed intervals and disseminatethis information locally.dissimilardissimilar /d|�smlə/ adjective refer-ring to something which is not the sameas, or is unlike, something else � Differ-

ential expansion switches operate onthe principle that the coefficients ofexpansion of dissimilar metals are dif-ferent.dissipate

dissipate /�dspet/ verb to spreadout and lose power or strength, or tocause something to do this � Tropicalstorms often dissipate as they pass fromsea to land.dissipation

dissipation /�ds|�peʃ(ə)n/ noun theprocess of spreading out and losingpower or strength � The rubber used onnose or tail wheels is usually con-structed to form a good electrical con-ductor for the safe dissipation of staticelectricity.dissolve

dissolve /d |�zɒlv/ verb to become orto cause to become part of a liquid andform a solution � Sugar dissolves inwater. � There is a possibility that insome types of accumulator, gas may bedissolved into the fluid and thus intro-duced into the system.dissolved

dissolved /d |�zɒlvd/ adjective thathas melted and become of a liquid �dissolved water water in solution infueldistance

distance /�dstəns/ noun a spacebetween two places or points, or themeasurement of such a space � The dis-tance from point A to point B is 100 nm.� The distance from point A to point Bon the diagram is 2 cm. � The height ofthe aircraft is the vertical distance,measured in feet, of the aircraft abovethe surface of the Earth.distance measuring equipment

distance measuring equipment/�dstəns �me"(ə)rŋ |�kwpmənt/noun an airborne secondary radarwhose signal is converted into distance� It is quite common to find a VORlocated together with DME (DistanceMeasuring Equipment) to give simulta-neous range and bearing from the samepoint on the ground. Abbreviation DME

COMMENT: DME equipment is usuallylocated in a VOR station. Otherequipment in the aircraft transmits asignal to the VOR station, whichreplies. The equipment in the aircraftconverts the signal into distance andalso calculates ground speed and thetime needed to reach the station.


75 diurnaldistillation

distillation /�dst|�leʃ(ə)n/ noun theprocess by which a liquid is heated andthe resulting vapour is then condensedand collected � With kerosene-typefuels, the volatility is controlled by dis-tillation.distinct

distinct /d|�stŋkt/ adjective clearand easily seen or understood � When alead-acid battery is fully charged, eachcell displays three distinct indications.distinction

distinction /d|�stŋkʃən/ nounsomething which makes one thing dif-ferent from another � A clear distinc-tion is made between showers and gen-eral precipitation.distinctivedistinctive /d |�stŋktv/ adjectiveeasily recognised because of particularfeatures or characteristics � Concorde isa very distinctive-looking aeroplane.distinguish

distinguish /d|�stŋ$wʃ/ verb toknow or to see the difference betweenthings � A receiver antenna would beunable to distinguish between signalsunless they had some differing charac-teristics.distinguishable

distinguishable /d |

�stŋ$wʃəb(ə)l/ adjective easily rec-ognised as different from � Usefulground features must be easily distin-guishable from their surroundings.distort

distort /d |�stɔ�t/ verb 1. to put out ofshape � Stress could cause the body ofthe aircraft to distort or change itsshape. 2. to produce a bad radio signal� The sound of the transmission is dis-torted if the volume is set too high.distortion

distortion /d |�stɔ�ʃ(ə)n/ noun 1. thebending or twisting of something sothat it is out of shape � Difficulty inclosing a door may be caused by distor-tion of the airframe. 2. alteration of theelectrical signal that makes a transmis-sion unclear � Distortion of the signalmade it difficult for the controller tounderstand what the pilot said.distress

distress /d |�stres/ noun 1. seriousdanger or difficulty 2. a personal worryor anxiety � Some passengers were indistress after the incident.distress and diversion cell

distress and diversion cell /d |

�stres ənd da |�v%�"(ə)n �sel/ noun aunit at an air traffic control centre that

provides immediate assistance to air-craft in difficultydistress signal

distress signal /d |�stres �s$n(ə)l/noun a signal transmitted by an aircraftin dangerdistribute

distribute /d|�strbju�t/ verb 1. togive or send out � There are two basicconfigurations which are used to dis-tribute electrical power, the parallelsystem and the split bus system. 2. tospread over a wide area � Multiplewheel undercarriage units distributethe weight of the aircraft.distribution

distribution /�dstr|�bju�ʃ(ə)n/ noun1. the act of giving or sending out � Par-allel AC and DC power distribution sys-tems are found on commercial aircraftcontaining three or more engines. 2. thefact of being spread over an area �

There is a high distribution of used anddisused airfields in the south of Eng-land.distributor

distributor /d |�strbjυtə/ noun adevice which sends an electrical chargeto each spark plug in turn � The distrib-utor directs the high voltage impulses tothe cylinders in turn as they reach theirignition point.disturb

disturb /d|�st%�b/ verb to upset thenormal condition of something � Smallhills can disturb the flow of air.disturbance

disturbance /d |�st%�bəns/ nounsomething that upsets the normal condi-tion of something � In general, thehigher the mountain and the faster theair flow the greater is the resulting dis-turbance.ditch

ditch /dtʃ/ verb to land a plane in thesea, in an emergency � Even though air-craft have ditched successfully, liveshave been lost because life rafts werenot launched in time.ditching

ditching /�dtʃŋ/ noun the act oflanding a plane in the sea, in an emer-gency � After all four engines stopped,the captain had to seriously considerthe possibility of a ditching in theIndian Ocean.diurnal

diurnal /da|�%�n(ə)l/ adjective refer-ring to the 24-hour cycle of day andnight � Diurnal changes in surface tem-perature over the sea are small.


dive 76divedive /dav/ noun a steep nose-downattitude of an aircraft � to pull out of orfrom a dive to return the aircraft tolevel flight after a nose-down flight path� During manoeuvring of an aircraft,when banking, turning and pulling outfrom a dive, stresses on the airframe areincreased. � verb to put the aircraft intoa steep nose-down attitude � The air-craft dived to avoid the other aircraft.(NOTE: diving – dived)divergediverge /da |�v%�d"/ verb to move fur-ther apart from something else � Airdiverges at low levels and converges athigh levels, causing a sinking or subsid-ing effect in the atmosphere. Oppositeconvergedivergencedivergence /da|�v%�d"əns/ noun theact of moving apart � Divergence of airat high levels leads to rising air at lowlevels with a consequent pressure fall.Opposite convergencedivergentdivergent /da|�v%�d"ənt/ adjectivereferring to something which movesfurther apart from something elsedivergent ductdivergent duct /da |�v%�d"ənt d�kt/noun a duct which has an inlet areawhich is smaller than the outlet areadiversiondiversion /da |�v%�ʃ(ə)n/ noun achange in route or destination caused bybad weather, technical problem, etc. �

The aircraft had to make a diversion toanother airport due to fog.divertdivert /da|�v%�t/ verb to turn awayfrom a course or a destination � Anautomatic cut-out valve is fitted todivert pump output to the reservoirwhen pressure has built up to normaloperating pressure. � The aircraft wasdiverted to Manchester airport becauseof fog.dividedivide /d |�vad/ verb 1. to separateinto parts � Air masses are divided intotwo types according to source regionand these are known as polar and trop-ical air masses. 2. to calculate howmany times a number is contained inanother number � Eight divided by fourequals two (8 ÷ 4 = 2).divisiondivision /d|�v"(ə)n/ noun 1. separa-tion into parts � the division of thelower atmosphere the separation of theatmosphere into its component layers 2.

the calculation of how may times anumber is contained in another number� The division sign is ÷.DME

DME abbreviation distance measuringequipmentdocument

document /�dɒkjυmənt/ noun apiece of writing, e.g. a memo, letter orreport � The flight crew route flight planis a composite document which alsoserves as a navigation log.documentationdocumentation /�dɒkjυmen |

�teʃ(ə)n/ noun a collection of letters,memos, reports, etc. � Flight crews areprovided with a full meteorologicalbriefing, backed by documentation, ashort time before ETD.domestic

domestic /də|�mestk/ adjectivereferring or belonging to inside a coun-try � Domestic flights usually leavefrom Terminal 1.dominantdominant /�dɒmnənt/ adjectivemain or most influential � Both pres-sure and temperature decrease withheight but the pressure change is thedominant one and so, as pressuredecreases with height, so does density.dominate

dominate /�dɒmnet/ verb to havethe most effect or influence on �

Because the chart time and the depar-ture/arrival times differ, it is necessaryto consider the movement of anyweather system which will dominate theroute.Doppler radarDoppler radar /�dɒplə �redɑ�/ nounradar which can distinguish betweenfixed and moving targets or provideground speed and track informationfrom an airborne installationDoppler VOR

Doppler VOR /�dɒplə vi� əυ �ɑ�/noun an adaptation of VOR to reduceerrors caused by locationdotdot /dɒt/ noun a small circular mark onpaper � The highest point in a locality ismarked by a dot with the elevationmarked alongside.downdraughtdowndraught /�daυndrɑ�ft/ noun 1.cool air which flows downwards as arainstorm approaches. Oppositeupdraught 2. air which flows rapidlydown the lee side of a building, moun-tain, etc. (NOTE: It is also written down-draft in US English.)


77 drivedownstreamdownstream /�daυn |�stri�m/ adverbin the direction of flow, or further alongthe line of flow � Internally drivensuperchargers are generally used onmedium and high powered engines andare fitted downstream of the throttlevalve.downwarddownward /�daυnwəd/ adjectivemoving to a lower level � When flying inturbulent air conditions, an aircraft issubjected to upward and downwardgust loads.downwardsdownwards /�daυnwədz/ adverb toa lower level, towards the bottom � Pullthe toggles downwards to inflate the lifejacket. Opposite upwards (NOTE: In USEnglish, downward is used as anadverb and as an adjective.)downwinddownwind /daυn |�wnd/ adjective,adverb in the same direction as the windis blowing � turn downwind turn theaircraft so that it is flying in the samedirection as the wind is blowing. Oppo-site upwinddownwind legdownwind leg /�daυnwnd le$/noun part of the airfield traffic circuitwhich runs parallel to, but in the oppo-site direction to, the approach to landwhich is made into windDRDR abbreviation dead reckoningdraftdraft /drɑ�ft/ noun US same asdraught � a down draft or an updraftdragdrag /dr�$/ noun the resistance of theair created by moving the aircraftthrough the air � To reduce the effect ofdrag on an aircraft by the fixed under-carriage a retractable type was intro-duced. � If an engine failure occurs, thewindmilling propeller may cause con-siderable drag.

COMMENT: There are two basic typesof drag called parasite drag andinduced drag. Parasite drag is causedby friction between the air and theaircraft surface, aerials, landing gear,etc. Induced drag is produced by lift.

draindrain /dren/ noun a device to allowfluid to escape from its container �

When the cabin is pressurised thedrains close, preventing loss of pres-sure. � verb to allow fluid to escape byproviding a hole or tube, etc., throughwhich it can pass � The moisture drains

in the lower skin of the cabin are openwhen the cabin is unpressurised, allow-ing moisture to drain.drainage

drainage /�drend"/ noun 1. the actof allowing a fluid to escape from itscontainer � Drainage of water from thefuel system should be carried out beforethe first flight of the day. 2. a system ofoutlets for fluid such as water or fuel topass out of a closed areadraught

draught /drɑ�ft/ noun a local currentof air � a down draught or an updraught(NOTE: This word is written draft in USEnglish.)draw

draw /drɔ�/ verb 1. to make a picture aswith a pencil, on paper, etc. � Becausethere is a temperature gradient acrosseach front it is possible to draw iso-therms which reduce in value fromwarm to cold air. 2. to pull or to take �

Fluid is drawn into the pump body. 3. topull towards oneself (NOTE: drawing –drew – drawn)drift

drift /drft/ noun movement awayfrom the desired course, created bywind blowing at an angle to theintended direction of flight � If the winddirection is not the same as the aircrafttrack or its reciprocal, then the aircraftwill experience drift. � verb to moveaway from the desired course � Whenlanding, a cross-wind from the rightwill cause the aircraft to drift to the left.drill

drill /drl/ noun 1. a short series ofactions carried out in a particularsequence � The starting drill variesbetween different aircraft types and astarting check procedure is normallyused. 2. a tool, often electrically pow-ered, for making holes in metal, wood,etc.drive

drive /drav/ noun a series of con-nected devices that transmit power tothe wheels, propellers, etc. � Rotationof the engine for starting is done by anelectric starter motor connected to adrive shaft in the accessories gearbox. �verb 1. to make something move or turn� shaft-driven using a rotating shaft asa means of transmitting power from onepart to another, e.g. from a turbineengine to a helicopter rotor 2. to control


driven 78

and guide � He’s learning to drive.(NOTE: driving – drove – driven)drivendriven /�drv(ə)n/ � drivedrizzledrizzle /�drz(ə)l/ noun precipitation,often persistent, in the form of verysmall drops of water � Drizzle is thelightest form of precipitation consistingof fine water droplets.

COMMENT: In weather reports andforecasts, drizzle is abbreviated to DZ.

drogue parachutedrogue parachute /�drəυ$�p�rəʃu�t/ noun a small parachute usedin releasing a larger parachute from itspackdronedrone /drəυn/ noun an aircraft whoseflight is controlled from the grounddropdrop /drɒp/ noun 1. a small amount ofliquid that falls � a drop of water � a fewdrops of rain 2. a sudden lowering � Thepassage of a cold front is usually fol-lowed by a drop in temperature. � Asudden drop in oil pressure is normallyan indication of serious engine trouble.� verb to become lower or to decreasesuddenly � The temperature dropped byseveral degrees.dropletdroplet /�drɒplət/ noun a small dropof liquid � Experiments show thatsmaller droplets of rain can remainsuper cooled to much lower tempera-tures than large droplets.drovedrove /drəυv/ � drivedrumdrum /dr�m/ noun a cylindricaldevice, often with closed endsdrydry /dra/ adjective containing nowater or no moisture � dry air � lapseratedry icedry ice /�dra �as/ noun solidified car-bon dioxidedualdual /�dju�əl/ adjective double, in pair� Most light aircraft with side-by-sideseating have dual controls.ductduct /d�kt/ noun a channel or tubethrough which fluids or cables can pass� The modern jet engine is basically aduct into which the necessary parts arefitted.duedue /dju�/ adjective 1. expected toarrive � the flight is due at 10 o’clockthe flight should arrive at 10 o’clock 2.� due to because of � Due to daytimeheating, the stability decreases and the

wind speed increases. � adverb exactlyand directly � The aircraft flew dueeast.dump

dump /d�mp/ verb to offload quickly� Normal operating cabin pressure canbe reduced rapidly in the event of emer-gency landings, by dumping air. � Theaircraft flew out to sea in order to dumpfuel before landing.duplicationduplication /�dju�pl|�keʃ(ə)n/ nounthe act of copying or doubling � Controlsurfaces are divided into sections oper-ated by a separate control unit, thusproviding duplication to guard againstfailure of a unit.durability

durability /�djυərə |�blti/ noun theability of a substance or device to last along time � High quality componentshave good durability.durationduration /djυ |�reʃ(ə)n/ noun thelength of time for which somethingcontinues � The duration of the exami-nation is two hours. � The duration ofthe flight was three hours.dust

dust /d�st/ noun a fine powdery sub-stance blown by the wind and found onsurfaces � Solid particles in the airinclude dust, sand, volcanic ash andatmospheric pollution.duty

duty /�dju�ti/ noun 1. a period of work� on duty at work � off duty not atwork 2. same as import duty � the dutypayable on a carton of cigarettesdyedye /da/ noun a material used tochange the colour of something �

Minute surface cracks which are diffi-cult to detect by visual means may behighlighted by using penetrant dyes.dynamic

dynamic /da |�n�mk/ adjectivereferring to something in motion �dynamic pressure pressure created bythe forward movement of the aircraft �

If the dynamic pressure increases due toan increase in forward speed, the forcerequired to move the control columnwill increase. Opposite static pressuredynamic sealdynamic seal /da |�n�mk �si�l/noun a seal which is part of a movingcomponent, e.g. in a hydraulic system �dynamic seals require lubrication toremain effectiveDZ

DZ /�di� �zed/ abbreviation drizzle


EEE abbreviation eastearear /ə/ noun the hearing organear defendersear defenders /�ə d|�fendəz/ pluralnoun same as acoustic ear muffseardrumeardrum /�ədr�m/ noun a membraneinside the ear which vibrates with soundand passes the vibrations to the innerear � Equalisation of the air pressureacross the eardrum is more difficult toachieve during descents than ascents.ear muffsear muffs /�ə m�fs/ plural noun �

acoustic ear muffsear protectorsear protectors /�ə prə |�tektəz/ plu-ral noun same as acoustic ear muffsearthearth /%�θ/ noun 1. � (the planet)Earth the planet where we live 2.ground or soil � verb to connect an elec-trical appliance to a position of zeropotential � When refuelling a light air-craft, ensure that the aircraft is properlyearthed. (NOTE: The US expression isto ground.)easteast /i�st/ noun 1. a compass point onthe mariner’s compass 90° clockwisefrom due north and directly oppositewest � London is east of New York. 2.the direction in which the Earth rotates,the direction of the rising sun � adjec-tive 1. referring to areas or regions lyingin the east � the east coast of Canada 2.the eastern part of a region � East Africa� adverb towards the east � The aircraftwas flying east.eastboundeastbound /�i�stbaυnd/ adjectivetravelling towards the east � an east-bound flighteasterlyeasterly /�i�stəli/ adjective 1. situatedtowards the east 2. � easterly compo-nent one part of the wind directioncoming from the east 3. � to move in an

easterly direction to move towards theeast � noun a wind which blows fromthe easteastern

eastern /�i�st(ə)n/ adjective situatedin the east � one of the eastern prov-inces of CanadaEastern Standard Time

Eastern Standard Time /�i�stən�st�ndəd �tam/ noun the time zone ofthe eastern USA and Canada, 5 hoursbehind GMT. Abbreviation ESTeastward

eastward /�i�stwəd/ adjective goingtowards the east � adverb US same aseastwardseastwards

eastwards /�i�stwədz/ adverbtowards the east � Flying eastwards orwestwards for long periods of timeaffects sleep patterns.east wind

east wind /i�st wnd/ noun a windblowing from or coming from the east(NOTE: A wind is named after the direc-tion it comes from.)EAT

EAT abbreviation expected approachtimeEATMP

EATMP abbreviation European airtraffic management programmeECAC

ECAC abbreviation European civilaviation conferenceECAM

ECAM abbreviation electronic central-ised aircraft monitorecho

echo /�ekəυ/ noun 1. the repetition ofa sound by reflection of sound wavesfrom a surface 2. the return of a signalback to the source from which it wastransmitted � The strength of the return-ing echo from a radar transmissiondepends on a number of factors.economic

economic /�i�kə|�nɒmk/ adjectivefinancially rewarding � It was no longer


economical 80

economic to keep the maintenanceoperation going.economicaleconomical /�i�kə |�nɒmk(ə)l/ adjec-tive referring to a substance or devicefor which input is minimised and outputmaximised (thereby saving costs) �economical engine an engine whichuses less fuel to produce the samepower as comparable engines � Jetengines are more efficient and econom-ical when operated at high altitudes.ECSECS abbreviation environmental con-trol systemEDDUSEDDUS abbreviation electronic datadisplay and update systemeddyeddy /�edi/ noun a current of air mov-ing in the opposite direction to the maincurrent, especially in a circular motion� When wind flows over an obstructionsuch as a building, an eddy is formed onthe lee, or downwind side.edgeedge /ed"/ noun a line of intersectionor joining of two surfacesEETEET abbreviation estimated elapsedtimeeffecteffect /|�fekt/ noun 1. somethingwhich results from a cause � Ultra-vio-let radiation has the effect of warmingthe atmosphere. � Pressure patternshave an effect on weather. 2. the condi-tion of being in full force � in effect inoperation � to take effect, to come intoeffect to start to operate � A new regula-tion comes into effect tomorrow. � witheffect from starting from � verb tocause or carry out � to effect a changeto make a change � modifications wereeffected modifications were carriedout. Compare affecteffectiveeffective /|�fektv/ adjective 1. hav-ing an expected and satisfactory result �the new cleaning fluid was very effec-tive it cleaned well 2. operative, ineffect � The regulation is effectiveimmediately.effectivenesseffectiveness / |�fektvnəs/ nounhow well something works � Ice cover-ing reduces the effectiveness of an aer-ial.effective pitcheffective pitch /|�fektv �ptʃ/ nounthe distance the aircraft moves forwardin flight for one 360° rotation of thepropeller

efficiencyefficiency /|�fʃ(ə)nsi/ noun 1. thefact of being able to act or producesomething with a minimum of waste,expense, or unnecessary effort � Effi-ciency is a key component of a success-ful business. 2. the ratio of the energydelivered by a machine to the energysupplied for its operation � mechanicalefficiency � propeller efficiency � ther-mal efficiency the efficiency of conver-sion of fuel energy to kinetic energyefficientefficient / |�fʃ(ə)nt/ adjective able toact or produce something with a mini-mum of waste, expense, or unnecessaryeffort � At some speeds and altitudesthe pure jet engine is less efficient thana piston engine. � efficient combustioncombustion in which fuel energy is usedto its maximum capabilityefforteffort /�efət/ noun 1. the use of physi-cal or mental energy to do something �

In order to qualify for a licence, it isnecessary to put some effort into thetraining course. � Flying a high per-formance aerobatic light aircraft to itslimits requires a lot of physical effort onthe part of the pilot. 2. force appliedagainst inertia � Actuators are capableof exerting low-speed turning effort.EFISEFIS abbreviation electronic flightinstrument systemeggbeatereggbeater /�e$bi�tə/ noun a rotary-wing aircraft (informal)EGNOSEGNOS noun a European system thatimproves the quality of data from exist-ing satellite navigation systems to makethe data suitable for use by aircraft. Fullform European Geostationary Navi-gation Overlay Service (NOTE: TheUS equivalent is WAAS.)EICASEICAS noun a cockpit display formonitoring the engines and warning ofmalfunction. Full form engine indicat-ing and crew alerting systemejecteject /|�d"ekt/ verb to throw out force-fully � On depressurisation the oxygenmask is ejected automatically from theservice panel.ejectionejection /|�d"ekʃən/ noun an act ofthrowing out forcefully � ejection seatejection seatejection seat /|�d"ekʃən si�t/, ejec-tor seat / |�d"ektə si�t/ noun an emer-gency escape seat in military aircraft


81 electronic

which is fired out of the aircraft whilethe crew-member is still in itejectorejector / |�d"ektə/ noun 1. a device tothrow something out forcefully 2. adevice using a jet of water, air, or steamto withdraw a fluid or gas from a space� A jet transfer pump or fuel ejector isused to transfer fuel.elapseelapse / |�l�ps/ verb to pass � Theradio altimeter works on the principlethat, if the path followed by the radiowave is straight down and up, then theelapsed time between the outgoing andincoming signal is a function of the air-craft’s height.elasticelastic /|�l�stk/ adjective flexible,easily returning to its original shapeafter being stretched or expanded � Atlow values of stress, if the plot of stressand strain is a straight line, this indi-cates that the material is elastic withinthis range.elasticityelasticity /�l� |�ststi/ noun the prop-erty of returning to an original form orstate following deformation � Titaniumfalls between aluminium and stainlesssteel in terms of elasticity, density andelevated temperature strength.electricelectric /|�lektrk/ adjective poweredor worked by electricityelectricalelectrical /|�lektrk(ə)l/ adjective 1.referring to electricity � an electricalfault 2. powered or worked by electric-ity � Activation may be mechanical orelectrical.electric currentelectric current / |�lektrk �k�rənt/noun the mass movement of electriccharge in a conductorelectricityelectricity /|�lek |�trsti/ noun anelectric current used to provide light,heat, powerelectric powerelectric power / |�lektrk �paυə/noun electricity used to drive machinesor deviceselectro-electro- / |�lektrəυ/ prefix electricityelectrodeelectrode /|�lektrəυd/ noun a solidelectrical conductor through which anelectric current enters or leaves an elec-trolytic cell � A battery has a positiveand a negative electrode.electrolyteelectrolyte / |�lektrəlat/ noun achemical compound that becomes con-

ductive when dissolved or molten � Theelectrolyte in a lead-acid battery con-sists of sulphuric acid diluted with dis-tilled water.electrolyticelectrolytic / |�lektrə|�ltk/ adjective� electrolytic cell a cell consisting ofelectrodes in an electrolyte solutionelectro-magnetelectro-magnet /|�lektrəυ�m�$nt/ noun a magnet consisting ofa coil of insulated wire wrapped arounda soft iron core that is magnetised onlywhen current flows through the wireelectro-magnetismelectro-magnetism /|�lektrəυ�m�$nə |�tz(ə)m/ noun a force exertedby a magnetic field found around anyconductor carrying current, the strengthof which will depend on the amount ofcurrent flowelectromotive forceelectromotive force /|

�lektrəυməυtv �fɔ�s/ noun a source ofelectrical energy required to produce anelectric current, produced by devicessuch as batteries or generators andmeasured in volts. Abbreviation emfelectronelectron /|�lektrɒn/ noun a sub-atomic particle that has a negative elec-trical charge � Electrons in the outerorbits of an atom may not be stronglyattracted to the nucleus and may be lost.electronicelectronic /�elek |�trɒnk/ adjectivereferring to, based on, operated by, orinvolving the controlled conduction ofelectrons especially in a vacuum, gas, orsemi-conducting material � Lightningdoes not often seriously damage air-craft but it may affect sensitive elec-tronic equipment.electronic centralised aircraft monitorelectronic centralised aircraftmonitor /�elektrɒnk �sentrəlazd�eəkrɑ�ft �mɒntə/ noun a display ontwo cathode ray tubes giving pilotsengine and systems information.Abbreviation ECAMelectronicelectronic flight instrumentsystem /�elektrɒnk �flat�nstrυmənt �sstəm/ noun primaryflight and navigation information on acathode ray tube. Abbreviation EFIS

COMMENT: The electronic flightinstrument system can show basicflight information and engineperformance information, as well asmoving maps and checklists.


element 82element

element /�elmənt/ noun 1. a sub-stance composed of atoms with an iden-tical number of protons in each nucleus� Elements cannot be reduced to sim-pler substances by normal chemicalmethods. 2. the resistance coil in anelectrical device such as a heater 3. aremovable component or removablepart, such as in an air filter or oil filterelevate

elevate /�elvet/ verb to move some-thing to a higher place or position froma lower one; to lift � In some light air-craft the magnetic compass is elevatedto a position as far away from the inter-fering effect of other components aspossible.elevated

elevated /�elə |�vetd/ adjective � ele-vated temperature increased or raisedtemperatureelevation

elevation /�elə|�veʃ(ə)n/ noun theheight at which something is above apoint of reference such as the ground orsea level � The highest point in a local-ity is marked by a dot with the elevationmarked alongside. � aerodrome eleva-tion distance in feet of the aerodromeabove sea level � Elevation is indicatedon charts by means of contour lines,spot heights, etc.elevator

elevator /�elvetə/ noun 1. a mova-ble control surface, usually attached tothe horizontal stabiliser of an aircraft,used to produce the nose up/downmotion of an aircraft in level flightknown as pitch � Elevators should bechecked for full and free movementimmediately prior to take-off. 2. USsame as lift noun 2

COMMENT: Some aircraft have an all-moving tailplane called a ‘stabilator’ (acombination of the words stabiliserand elevator).

eliminate

eliminate /|�lmnet/ verb to get ridof or remove � Air dryers are providedto eliminate the possibility of ice form-ing. � To eliminate the need for complexmechanical linkage, the selector isoperated electrically. � to eliminate adanger to remove a dangerellipse

ellipse /|�lps/ noun an oval-shapedline � Each planet moves in an ellipseand the sun is at one of the foci.

ellipticalelliptical /|�lptk(ə)l/ adjective hav-ing an oval shape � the elliptical path ofthe Earth around the sunELRELR abbreviation 1. environmentallapse rate 2. extra long range (ICAO)embarkationembarkation /�embɑ� |�keʃ(ə)n/noun the act of going onto an aircraft �

Embarkation will start in ten minutes.(NOTE: Boarding is usually preferred.)� embarkation time the time at whichpassengers will be asked to go onto theaircraftembedembed /m |�bed/ verb to fix firmly in asurrounding mass � A temperatureprobe is embedded into the stator of thegenerator. � Water outlets have heaterelements embedded in rubber seals inthe outlet pipe.emergencyemergency / |�m%�d"ənsi/ noun aserious situation that happens unexpect-edly and demands immediate action �

to deal with or to handle an emergencyemergency descentemergency descent / |�m%�d"ənsid |�sent/ noun a planned rapid losing ofaltitude because of a serious situationemergency equipmentemergency equipment noundevices for use only in serious situa-tionsemergency exitemergency exit / |�m%�d"ənsi�e$zt/ noun a way out only to be usedin case of an emergency � How manyemergency exits are there in the air-craft?emergency frequencyemergency frequency / |

�m%�d"ənsi �fri�kwənsi/ noun 121.5MHz, the frequency on which aeronau-tical emergency radio calls are madeemergency landingemergency landing / |�m%�d"ənsi�l�ndŋ/ noun a landing made as aresult of an in-flight emergencyemergency proceduresemergency procedures pluralnoun a set of actions pre-planned andfollowed in the event of a serious situa-tionemergency servicesemergency services / |�m%�d"ənsi�s%�vsz/ plural noun the fire, ambu-lance and police services � The alarmwill activate the emergency services.emfemf abbreviation electromotive forceemissionemission /|�mʃ(ə)n/ noun 1. theprocess of sending out e.g. matter,energy or signals � light emissions �


83 engine block

radio emission � One factor on whichthe operational range of a radio emis-sion depends is the transmitted power.2. a substance discharged into the air, asby an internal combustion engine �

Exhaust emissions contain pollutants.emit

emit /|�mt/ verb to send out e.g. mat-ter, energy or radiation � radiation emit-ted by the sun � An X-ray tube emitsradiation. � Latent heat is emitted whencondensation takes place. (NOTE: emit-ting – emitted)empennage

empennage /em |�pend"/ noun thetail assembly of an aircraft � Theempennage usually includes the fin,rudder, horizontal stabiliser (or tail-plane), and elevator.emphasis

emphasis /�emfəss/ noun force ofexpression that gives importance tosomething � It is only in recent yearsthat much emphasis has been placed ondetermining the causes of metal fatigue.emphasise

emphasise /�emfəsaz/, emphasizeverb to give importance to something �

On some maps, different elevations areemphasised by colouring.employ

employ /m |�plɔ/ verb 1. to use �

There are two methods employed tocool the cylinders down. � In some air-craft, particularly those employingnickel-cadmium batteries, temperaturesensing devices are located within thebatteries to provide a warning of highbattery temperatures. 2. to give some-body regular paid workempty weight

empty weight /�empti wet/ theweight of a plane without fuel, peopleor freightenable

enable /n|�eb(ə)l/ verb to makesomething possible or easier � Isolationvalves are fitted to enable servicing andmaintenance to be carried out.enclose

enclose /n |�kləυz/ verb to surroundon all sides � The housing encloses thevarious mechanical parts. � Fuses forma weak link in a circuit and are usuallymade of a strip of tinned copperenclosed in a glass tube.encode

encode /n |�kəυd/ verb to put intocode � Weather information is encodedto allow large amounts of informationto be given in a short space of time.

encounter

encounter /n |�kaυntə/ verb to meetsomething unexpected or unwanted �

Severe icing can be encountered inwave cloud.endurance

endurance /n |�djυərəns/ noun thelength of time an aircraft can stay in theair without refuelling � The flight timeto the PNR and back will equal theendurance of the aircraft.energy

energy /�enəd"i/ noun 1. the ability ofa physical system to do work 2. powerfrom electricity, petrol, heat, etc. � Theengine converts heat energy intomechanical energy. � The generatorconverts mechanical energy into elec-trical energy.engage

engage /n|�$ed"/ verb 1. to switchon and use � The autopilot may beengaged during climb or descent.Opposite disengage 2. � engaged inworking on a particular job or task �

Personnel engaged in ground runningmust ensure that any detachable cloth-ing is securely fastened and they shouldwear acoustic ear muffs.engine

engine /�end"n/ noun a machine thatconverts energy into mechanical forceor motion, different from an electric orhydraulic motor because of its use of afuel � jet engine � piston engine � inter-nal combustion engine � combustion,jet, piston � engine-driven referring toequipment and devices which take theirpower from the engine when it is run-ning � engine-driven generator �

engine-driven pump � engine runningengine operating or working � theengine is running the engine is work-ing � The accident investigation demon-strated that the engine was running atfull power when the aircraft hit theground.

COMMENT: In British usage, there is aclear distinction between the terms‘engine’ and ‘motor’, the term ‘motor’only being used for electric powerunits. In American usage, however,‘motor’ is used for all types of powerunit including the internal-combustionengine.

engine block

engine block /�end"n blɒk/ noun acylinder block with integral crankcase


engine capacity 84engine capacityengine capacity /�end"n kə|�|

�p�sti/ noun the swept volume of anengineengine compartmentengine compartment /�end"nkəm |�pɑ�tmənt/ noun a space in the air-frame where the engine is locatedengineerengineer /�end"|�nə/ noun a personwho is qualified to design, build andrepair machines � aircraft engineer anengineer who specialises in the mainte-nance and repair of aircraftengineeringengineering /�end" |�nərŋ/ nounthe use of scientific and mathematicalprinciples for practical reasons such asthe design, manufacture, and operationof machines and systems, etc. � aircraftengineering the branch of aviation con-cerned with the maintenance and repairof aircraft � Reinforced plastics or com-posites are being used in aircraft engi-neering instead of metals because theyare much lighter.engine failureengine failure /�end"n �feljə/noun a situation in which an enginestops during runningengine indicating and crew alerting systemengine indicating and crewalerting system /�end"n�ndketŋ ən �kru� ə|�l%�tŋ �sstəm/noun full form of EICASengine instrumentsengine instruments /�end"n�nstrυmənts/ plural noun instrumentswhich give the pilot information aboutengine temperature, speed, etc.engine intakeengine intake /�end"n �ntek/noun the front part of the engine whereair enters the engineengine malfunctionengine malfunction /�end"n m�l|

�f�ŋkʃən/ noun a situation in which theengine does not work as it shouldengine oilengine oil /�end"n ɔl/ noun oil usedespecially to lubricate enginesengine performanceengine performance /�end"n pə |

�fɔ�məns/ noun a description of howwell the engine works or detailed statis-tical information about the capabilitiesof the engineenhanceenhance /n |�hɑ�ns/ verb to makegreater or better or clearer � Chances ofsurvival are enhanced if passengersknow where the emergency exits are.

‘…any automation must be designed toenhance the decision making abilities of

the crew, not replace them’[INTER PILOT]

enhancementenhancement /n |�hɑ�nsmənt/ nounthe process of making greater, better orclearer � enhancement of an image ona screen the improvement of an imageon a screenenlargeenlarge /n|�lɑ�d"/ verb to make big-ger or larger � enlarge the hole makethe hole biggerenplaneenplane /en|�plen/ verb to board orallow somebody to board an aircraften routeen route /�ɒn �ru�t/ adverb, adjectiveon or along the way � en route fromNew York to London on the way fromNew York to London � en route alter-nate an airfield where it is possible toland if there is an in-flight problem � enroute weather conditions a descriptionof the weather along the path of flightensureensure /n |�ʃυə/ verb to make certain,to make sure � The generator cut-outensures that the battery cannot dis-charge. � Before the engine is stopped,it should normally be allowed to run fora short period at idling speed, to ensuregradual cooling.enterenter /�entə/ verb 1. to come or go into� Air enters at the front of the cabin andleaves at the rear. 2. to write down e.g.information � Enter the rectified air-speed in the log. � Enter your name inthe correct place in the form. 3. to putdata into a computer, especially byusing the keyboard to type it in � Enterthe data into the computer.entireentire /n|�taə/ adjective whole, hav-ing no part excluded or left out � theentire life of a thunderstorm the com-plete life of a thunderstormentryentry /�entri/ noun 1. the act orinstance of going in � the flow of trafficat entry points to the airfield. 2. thewriting in of an item, as in a record orlog � An entry should be made in thetechnical log.entry pointentry point /�entri pɔnt/ noun aposition on the ground above which anaircraft entering a control zone crossesthe boundaryenvelopenvelop /n |�veləp/ verb to surroundand cover � The atmosphere envelopsthe earth.


85 equivalent shaft horsepowerenvelope

envelope /�envələυp/ noun 1. the setof limitations within which a techno-logical system, especially an aircraft,can perform safely and effectively �

The boundaries of flight envelopes varybetween aircraft categories and per-formance groups but in each case, thereis a speed which must not be exceededwhich is called the Vne (never-exceedspeed). 2. a cover � The atmosphere isthe gaseous envelope surrounding theearth.environment

environment /n|�varənmənt/ noun1. nearby conditions or circumstances �A body of air warmer than its environ-ment will rise. � a non-computer envi-ronment a computer-free working situ-ation 2. the natural world in whichpeople, animals and plants live � Peopleare interested in issues to do with theenvironment, such as global warming.environmental

environmental /n |�varən |

�ment(ə)l/ adjective referring to theimmediate surroundings � environmen-tal conditionsenvironmental control system

environmental control system/n |�varənment(ə)l kən |�trəυl�sstəm/ noun an air-conditioning sys-tem for the aircraft. Abbreviation ECSenvironmental lapse rate

environmental lapse rate/�nvarənment(ə)l �l�ps �ret/ nounthe rate at which the temperature of theair falls as one rises above the earth �

Although there is an average ELR of1.98°C per 1,000 feet, in practice theELR varies considerably with spaceand time. Abbreviation ELRepoxy-based primer

epoxy-based primer / |�pɒksibest �pramə/ noun a primer contain-ing epoxy resin, a substance which,with the addition of hardeners, becomesvery strong and hard after a time at nor-mal temperaturesequal

equal /�i�kwəl/ adjective having thesame quantity, measure, or value asanother � For every action, there is anequal and opposite reaction. � verb tobe the same in value as � Two plus twoequals four (2 + 2 = 4).equalise

equalise /�i�kwəlaz/, equalize verbto become the same in quantity, meas-ure or value � Fluid pressure and gas

pressure equalise at normal systempressure.equate

equate /|�kwet/ verb to be the sameas � In an electrical circuit, an increasein length equates to an increase inresistance.equation

equation /|�kwe"(ə)n/ noun a state-ment, usually in symbols, that twoquantities or mathematical expressionsare equal � X2 + Y2 = Z2. � The equa-tion Vg = P can be used to find the geos-trophic wind.equator

equator /|�kwetə/ noun the imagi-nary great circle around the Earth’s sur-face, equidistant from the poles and per-pendicular to the Earth’s axis of rotationwhich divides the Earth into the north-ern hemisphere and the southern hemi-sphere � Every point on the equator isequidistant from the poles.equatorial

equatorial /�ekwə |�tɔ�riəl/ adjectivereferring to the equator or to conditionsthat exist at the Earth’s equator � equa-torial heat � equatorial climateequilibrium

equilibrium /�i�kw |�lbriəm/ noun astate of physical balance � When an air-craft is in unaccelerated straight andlevel flight at a constant speed, theforces of lift, thrust, weight and dragare in equilibrium.equipment

equipment / |�kwpmənt/ noundevices, systems, machines, etc., thatare needed for a particular purpose(NOTE: Equipment has no plural form;for one item say: a piece of equipment.)� electrical equipment devices, com-ponents, systems, etc., which use elec-tricityequivalent

equivalent / |�kwvələnt/ adjectivehaving the same purpose or value assomething else � The function of a logicgate is equivalent to that of a switch. �

A metal part could be as much as 25times heavier than an equivalent plasticpart.equivalent shaft horsepower

equivalent shaft horsepower /|

�kwvələnt ʃɑ�ft �hɔ�spaυə/ noun theunit used for stating the total power of aturboprop engine, consisting of theshaft horsepower of the engine plusthe thrust from the engine. Abbrevia-tion ESHP


error 86errorerror /�erə/ noun 1. a mistake or incor-rect calculation � an error in some-body’s work � errors caused by location2. the known inaccuracy of an instru-ment or system which has to be cor-rected by calculating the true valueescapeescape /|�skep/ noun the act of get-ting away from or out of a place afterbeing held � escape of fuel or oilunwanted loss of fuel or oil � escapefrom danger getting to a safe place �

verb to get away from or out of afterbeing held � If there is a hole in thefuselage of a pressurised aircraft, airescapes from the cabin to the atmos-phere.escape hatchescape hatch / |�skep h�tʃ/ noun asmall doorway only used in emergen-ciesescape routeescape route / |�skep ru�t/ noun thepassengers’ way out of an aircraft afteran emergency landingescape slideescape slide /|�skep slad/ noun adevice which allows passengers to exitthe aircraft safely in an emergency,when no steps are availableESHPESHP abbreviation equivalent shafthorsepoweressentialessential /|�senʃəl/ adjective abso-lutely necessary � Teamwork within thecrew is essential. � A knowledge of thetropopause is essential. � non-essentialnot necessaryESTEST abbreviation 1. Eastern StandardTime 2. estimate (ICAO) 3. estimated(ICAO)establishestablish / |�st�blʃ/ verb 1. to beconfirmed as stable in a particular flightcondition, such as a flight level orglideslope, etc. � Once established onthe downwind leg, the pilot should per-form the checks. 2. to work out or to cal-culate � establish your position findout where you are 3. to position � Low-power NDBs (Non-Directional RadioBeacons) are often established at theouter or middle marker sites. 4. � toestablish communication to makecontact with � to establish control toget controlestimateestimate /�estmet/ verb 1. to calcu-late approximately the cost, value orsize of something � I estimate that it

will take about two hours for us to reachour destination. � Cloud heights may bemeasured or estimated. 2. to form ajudgement about � to estimate thechances of something to weigh thepossibilities and form an opinionestimated take-off time

estimated take-off time/�estmetd �tek ɒf �tam/ noun thetime when an aircraft is expected to takeoff. Abbreviation ETOTestimated time of arrivalestimated time of arrival/�estmetd �tam əv ə |�rav(ə)l/ nounthe time when an aircraft is expected toarrive. Abbreviation ETAestimated time of departure

estimated time of departure/�estmətd �tam əv d |�pɑ�tʃə/ nounthe time when an aircraft is expected totake off. Abbreviation ETDestimation

estimation /�est |�meʃ(ə)n/ noun 1.an approximate calculation � an estima-tion of ground speed � Estimation ofvisibility is achieved by noting the dis-tances at which lights of known candlepower can be observed and relatingthese distances to visibility-by-day val-ues. 2. an opinion � in my estimation inmy opinionETA

ETA abbreviation estimated time ofarrivalETD

ETD abbreviation estimated time ofdepartureETOTETOT abbreviation estimated take-offtimeEurocontrolEurocontrol /�jυərəυkən |�trəυl/noun the European organisation for thesafety of air navigation (NOTE: Eurocon-trol operates the ATC centre at Maas-tricht in the Netherlands and the Cen-tral Flow Management Unit inBrussels.)European Geostationary Navigation Overlay Service

European Geostationary Navi-gation Overlay Service/�jυərəpiən �d"i�əυsteʃ(ə)n(ə)ri�n�v$eʃ(ə)n �əυvəle �s%�vs/ nounfull form of EGNOSevacuateevacuate /|�v�kjuet/ verb 1. toremove all the people from somewherein the event of an emergency � to evac-uate all passengers from the airport 2.to empty somewhere of all people in itbecause of an emergency � to evacuatethe aircraft 3. to create a vacuum �


87 examination

evacuate a glass jar remove all the airfrom a glass jarevacuation

evacuation /|�v�kju |�eʃ(ə)n/ noun1. the act of removing all people fromsomewhere in the event of an emer-gency � The evacuation of the passen-gers from the airport was not ordered.2. an act of emptying somewhere of allpeople in it because of an emergency �

The evacuation of the aircraft did nottake long. � evacuation command anevacuation order from the captain �ditching evacuation an evacuationafter the aircraft has force-landed onwaterevaluate

evaluate / |�v�ljuet/ verb to examineand judge carefully � Deposits of iceare detected and continuously evalu-ated to operate a warning system.evaluation

evaluation /|�v�lju|�eʃ(ə)n/ nounthe examination and judgement ofsomething � The ice detector systemprovides continuous evaluation of con-ditions conducive to the formation ofice.evaporate

evaporate /|�v�pəret/ verb to con-vert or change a liquid into a vapour � Inthe heat of the day, water evaporatesfrom the surface of the earth. Oppositecondenseevaporation

evaporation /|�v�pə|�reʃ(ə)n/ nounthe changing of a liquid into vapour,vaporisation � Carburettor icing can becaused by the expansion of gases in thecarburettor and the evaporation of liq-uid fuel.even

even /�i�v(ə)n/ adjective 1. flat orsmooth, with no bumps or dents 2. thesame in all parts of an area or over awhole surface � an even distribution ofpassengers � an even application ofpaint 3. � even numbers exactly divis-ible by 2, e.g. 4, 6, 20 � adverb 1. yetmore � It will be even higher than thenew building. � even faster not just asfast as, but more 2. � even if whether ornot � Stop at the holding point even ifthere are no other aircraft on theapproach. � even though in spite of thefact that � He gained his private pilot’slicence even though he was 73 yearsold.

event

event /|�vent/ noun a happening � TheParis air show is a major event. � in theevent of if something should happen �

Passengers should fasten their seatbelts in the event of turbulence. � in theevent of main pump failure if thereshould be a failure of the main pump �in the event of fire if there should be afireeventual

eventual /|�ventʃuəl/ adjective hap-pening at an unspecified time in thefuture � Water in the fuel may lead toeventual engine stoppage.eventually

eventually / |�ventʃuəli/ adverb at anunspecified time in the future � Vapourcools and eventually condenses.evidence

evidence /�evd(ə)ns/ noun an out-ward sign � external evidence ofcracks something which can be seen onthe surface which suggests that there isa deeper structural problem � Deformedwing panels may be evidence of anover-stressed airframe.evident

evident /�evd(ə)nt/ adjective obvi-ous, easily seen or understood � It isevident from the information availablethat language problems played a part inthe cause of the accident. � self-evidentclear in itself, without further explana-tionexact

exact /$|�z�kt/ adjective completelyaccurate or correct � The exact fuel flowand pressure is adjusted. � the calcula-tion is not exact the calculation is not100% correctexactly

exactly /$|�z�ktli/ adverb 1. accu-rately, correctly � Measure the quantityexactly. 2. absolutely, completely � Afuel injection system performs exactlythe same function as a carburettor.examination

examination /$ |�z�m|�neʃ(ə)n/noun 1. a set of questions or exercisestesting knowledge or skill � The exami-nation includes a flight plan. 2. � med-ical examination medical check-up 3. acareful observation or inspection � theexamination of a faulty component

‘…the pilot of a Grumman Cheetahrefused to be breathalysed, and was takento a police station for examination by apolice surgeon, who confirmed that hehad been drinking’ [Pilot]


examine 88examineexamine /$|�z�mn/ verb 1. to findout how much knowledge or skill some-body possesses by means of questionsor exercises � Students will be examinedin four subjects. 2. to test or check thecondition or health of somebody � toexamine a patient 3. to study or analysesomething � to examine chartsexceedexceed /k |�si�d/ verb to be greaterthan � Vertical velocity of updraughtscan exceed 50 kt.exceptionexception /k |�sepʃən/ noun some-thing or somebody not included � anexception to the rule an examplewhich does not conform to a generalrule � with the exception of not includ-ing � with the exception of Smith, allthe students passed their examsSmith did not pass, but the other stu-dents didexceptionalexceptional /k |�sepʃən(ə)l/ adjec-tive 1. being an exception, uncommon �in exceptional circumstances in unu-sual circumstances 2. well above aver-age, extraordinary � an exceptionalpilot a very good pilotexcessexcess /k |�ses/ noun an amount orquantity beyond what is normal or suf-ficient � excess power the differencebetween horsepower available andhorsepower required � in excess ofmore than � a height in excess of50,000 feet a height greater than 50,000feetexcess baggageexcess baggage /�ekses �b�$d"/noun an amount, usually expressed asweight, of baggage which exceeds theairline’s limit per passengerexcessiveexcessive /k |�sesv/ adjective morethan the normal, usual, reasonable, orproper limit � Excessive use of powerwhen taxiing will require excessive useof brakes.exchangeexchange /ks|�tʃend"/ verb to givein return for something received �

Meteorological stations exchangeinformation with other meteorologicalstations.excitationexcitation /�eks |�teʃ(ə)n/ noun theact of supplying a small current to thewindings of larger electrical motors,etc. � Pilot excitation consists of a pilotexciter and a main exciter, to provide

the direct current for the motor of thealternating current generator.exciter

exciter /k |�satə/ noun the source of asmall current to supply electrical cur-rent to the windings of larger electricalmotors, etc., e.g. a battery � Pilot exci-tation consists of a pilot exciter and amain exciter, to provide the direct cur-rent for the motor of the alternatingcurrent generator.exclude

exclude /k |�sklu�d/ verb to keep out,to prevent from entering � Joints andinterfaces should exclude moisture andimprove fatigue life.exercise

exercise /�eksəsaz/ noun an activitythat requires physical or mental effort orpractice � a classroom exercise � Swim-ming is good physical exercise for peo-ple such as pilots who spend a lot oftime sitting down. � verb to use or to putinto play or operation � Student pilotsmust exercise special care when land-ing in a strong crosswind.exert

exert /$ |�z%�t/ verb � to exert a forceto put a force on something � Pressureis the force per unit area exerted by theatmosphere on a given surface area. �to exert an influence to have an influ-ence � to exert pressure to put pressureonto somethingexhaust

exhaust /$|�zɔ�st/ noun 1. the escapeor release of vaporous waste materialfrom an engine 2. a pipe through whichwaste gases pass out of the engine � Theexhaust valve opens to allow for the exitof exhaust gases. � verb to consume oruse up all of something � Supplies offuel are exhausted. (NOTE: To run out isless formal.)exhaust gas

exhaust gas /$|�zɔ�st $�s/ noun gaswhich is the product of the combustionprocess and which is passed out throughthe exhaust system � Exhaust gasescontain carbon monoxide.exhaust system

exhaust system /$ |�zɔ�st �sstəm/noun a system of pipes, silencers, etc.,which carry exhaust gases from theengine to a point where they arereleased into the atmosphereexhaust valve

exhaust valve /$ |�zɔ�st v�lv/ nouna valve in a piston engine which allowsexhaust gases to leave the cylinder


89 experimentalexhibitexhibit /$|�zbt/ verb to have or todisplay � Composites, due to their con-struction, exhibit good fatigue behav-iour. � Altocumulus are (usually) whitelayers or patches of cloud frequentlyexhibiting a waved appearance.existexist /$|�zst/ verb to be present underparticular circumstances or in a speci-fied place � Water can exist in theatmosphere in three forms. � A fire riskmay exist following failure or leakage ofany component.existenceexistence /$ |�zstəns/ noun the factor state of being � Warning systems areprovided to give an indication of a pos-sible failure or the existence of a dan-gerous condition.exitexit /�e$zt/ noun 1. the act of goingout of a place � The exhaust valve opensto allow for the exit of exhaust gases. �exit velocity the velocity of exhaustgases from a jet engine 2. a way outexit nozzleexit nozzle /�ekst �nɒz(ə)l/ noun apipe or opening through which exhaustgases leave a jet engineexit pointexit point /�ekst pɔnt/ noun a posi-tion on the ground above which an air-craft leaving a control zone crosses theboundaryexpandexpand /k|�sp�nd/ verb to increase insize, volume or quantity, to enlarge �

Air expands when heated and contractswhen cooled.expansionexpansion /k |�sp�nʃən/ noun anincrease in size, volume or quantity �

There is an expansion of the gas when itis heated.expansion chamberexpansion chamber /k |�sp�nʃən�tʃembə/ noun a container whichallows for expansion of a fluid causedby increase in temperature, etc.expectexpect /k |�spekt/ verb to hope or toassume that something is going to hap-pen � the weather to be expected alonga route � We expect flight AC 309 withinten minutes. � as might be expected aspeople think would happen

‘…by 1959 there were some 40 pilotspast age 60 flying the line with thenumber expected to rise to 250 within thenext few years’ [INTER PILOT]

expectedexpected /k |�spektd/ adjectivebeing thought or hoped to be taking

place � the expected number of passen-gersexpected approach time

expected approach time /k|

�spektd ə |�prəυtʃ �tam/ the time atwhich air traffic control expects anarriving aircraft to complete itsapproach for landing, following a delay.Abbreviation EATexpedite

expedite /�ekspdat/ verb to speedup the progress of � to expedite theevacuation to speed up the evacuation �to expedite the disembarkation to getthe passengers off the aircraft quicklyexpel

expel /k|�spel/ verb to force out, todrive out � Exhaust gases are expelledfrom the cylinder by the upward move-ment of the piston. � The piston drawsfluid into the cylinders on the outwardstroke and expels fluid into the systemon the inward stroke.experience

experience /k |�spəriəns/ noun 1.the building up of knowledge or skillover a period of time by an active partic-ipation in events or activities � a pilotwith 20 years’ experience 2. an event orincident � The first solo is an experi-ence most pilots never forget. � verb toundergo, participate in or find oneself ina particular situation � It is not unusualto experience traffic delays on theground prior to departure. � Turbulencecan be experienced when flying througha trough.experiment

experiment noun /k |�spermənt/ ascientific test, carried out under control-led conditions, that is made to demon-strate or discover something � Experi-ments have shown that left-handedpeople often have better hand/eye coor-dination than right handed people. � toconduct an experiment to perform anexperiment � verb /k |�sperment/ � toexperiment (with) to carry out a scien-tific test under controlled conditions inorder to demonstrate or discover some-thingexperimental

experimental /k |�sper|�ment(ə)l/adjective referring to something still atan early stage of development, not triedand tested � the experimental and test-ing stages of a new type of aircraft. � anexperimental aircraft an aircraftdesigned to be used for experimental


explanatory 90

purposes � The experimental aircraftwere used to investigate high-speedflight.explanatoryexplanatory /k |�spl�nət(ə)ri/ adjec-tive referring to something whichexplains � explanatory paragraph aparagraph of text which explains some-thing � self-explanatory somethingwhich does not need any further expla-nationexplosionexplosion /k|�spləυ"(ə)n/ noun 1. arelease of energy in a sudden and oftenviolent way � an explosion caused by abomb 2. an act of bursting as a result ofinternal pressure � tyre explosion due tooverheating 3. the loud sound made asa result of an explosion � The passen-gers heard an explosion.explosiveexplosive /k |�spləυsv/ adjectivereferring to something having thenature of an explosion � an explosiveeffect having the effect of an explosion� noun a substance, especially a pre-pared chemical, that explodes or causesexplosions, e.g. Semtexexposeexpose /k |�spəυz/ verb to uncoversomething or leave something uncov-ered so that it is not protected fromsomething such as rain or sunlight �

When the slope of a hill is exposed tosolar radiation, wind currents are setup. � exposed to the sun in sunlightwithout covering � exposed surface asurface without paint or covering of anysortexposure

exposure /k |�spəυ"ə/ noun 1. thefact of being exposed, especially tosevere weather or other forces of nature� After 24 hours in the sea, she was suf-fering from the effects of exposure andwas taken to hospital. 2. the fact ofbeing subjected to something � Expo-sure to radio-active substances maycause cancer.expressexpress /k |�spres/ verb to put intowords, symbols or signs � Bearingsmay be expressed as true or relative. �

An angle may be expressed in degrees,minutes and seconds. � Pressure alti-tudes are expressed in hundreds of feet.extendextend /k |�stend/ verb to stretch orspread from one point to another inspace or time � Air from the Gulf of

Mexico can extend into Canada. �

Cumulonimbus clouds may extend toover 50,000 ft. � to extend the dura-tion of something to prolong the time �The visit was extended to allow time formore discussions.extensiveextensive /k |�stensv/ adjectivelarge in range or amount � an extensivearea a large area � extensive cloud a lotof cloud � extensive use is made ofmuch use is made ofextentextent /k |�stent/ noun a range oramount of something � The horizontalextent of the cloud averages about 50km. � Clouds of great vertical extent arenot uncommon. � to a certain extent, tosome extent partly � The accident wascaused, to a certain extent, by the poorweather. � to a lesser extent not asmuch as something previously stated �

The cloud types which are most likely toaffect flying conditions in terms oficing, precipitation and turbulence arecumulus, cumulonimbus and, to a lesserextent, nimbostratus.externalexternal /k|�st%�n(ə)l/ adjective refer-ring to, existing on, or connected withthe outside or an outer part � The onlyexternal force acting on air is gravity.Opposite internal � external appear-ance the appearance of something fromthe outsideexternal ambient pressure

external ambient pressure /k |

�st%�n(ə)l ��mbiənt �preʃə/ noun pres-sure outside the aircraftextinguish

extinguish /k|�stŋ$wʃ/ verb to putout � The fire services extinguished thefire.extinguisher

extinguisher /k|�stŋ$wʃə/ noun aportable mechanical device for spray-ing and putting out a fire with chemicals� Hand-operated fire extinguishers areprovided to combat any outbreaks offire in the flight crew compartment andpassengers’ cabins.extractextract noun /�ekstr�kt/ a part takenfrom a longer text � The following par-agraph is an extract from a flight man-ual. � verb /k |�str�kt/ 1. to obtain froma substance by chemical or mechanicalaction � A dehumidifier extracts mois-ture from the atmosphere. 2. to take outor to obtain information from some-


91 eye

thing � Extract the important informa-tion from a text.extrapolateextrapolate /k|�str�pəlet/ verb toestimate by using known facts � Infor-mation given on a synoptic chart can beextrapolated, by the use of some simpleguidelines.extremeextreme /k|�stri�m/ adjective 1. mostdistant in any direction, the outermostor farthest � the most extreme point onthe map 2. to the greatest or highest

degree, very great � extreme care mustbe taken the greatest care must be taken� extreme difficulty great difficulty �

noun either of the two things, values,situations, etc., situated at opposite endsof a range � the extremes of boiling andfreezing � The region experiencesextremes of temperature.eye

eye /a/ noun an organ in the headwhich lets you see. � coordination,vision


FFF symbol 1. Fahrenheit 2. faradFAAFAA abbreviation US Federal AviationAdministrationfabricfabric /�f�brk/ noun material or clothproduced especially by knitting orweaving � A breathing mask has a fab-ric carrying bag.fabricatefabricate /�f�brket/ verb to makeor manufacture � Selected wing panelsare fabricated entirely from magnesiumalloys. � The ease with which alumin-ium can be fabricated into any form isone of its most important qualities.faceface /fes/ noun 1. the surface of anobject � the face of the earth � Theexhaust cone prevents the hot gasesfrom flowing across the rear face of theturbine disc. � the north face of themountain the vertical or near-verticalside facing north 2. the front part withdial, indicators, etc. � the face of aninstrument � the face of a clock thefront part of the clock with numbers 3.the front of the head, including the eyes,nose, mouth � full face smoke mask aprotective mask for fighting fires whichcovers the whole face � verb to beturned towards a particular direction �

Hills and mountains which face the sunreceive more intense radiation. � thebuilding faces north the building hasits front towards the northfacilitatefacilitate /fə |�sltet/ verb to enablesomething to happen more easily orquickly � A ramp is used to facilitateaccess to the wing. � Clearly markedexits facilitate rapid evacuation of pas-sengers.facilityfacility /fə |�slti/ noun 1. ability orease in moving, acting, or doing some-

thing � a facility in learning to fly agood natural ability for flying 2. aninstallation or building which providesspecific operating assistance � DME(Distance Measuring Equipment)ground facility 3. a mode of operationwhich allows the user of equipment todo something � The printer has a self-test facility. 4. � facilities things, espe-cially buildings or equipment, that peo-ple can use � a clubhouse with goodfacilities a clubhouse with a number offeatures which can be used by membersand guests, e.g. restaurant, bar, readingroom, swimming pool � medical facili-ties hospitals, clinics, etc.facsimile

facsimile /f�k|�smli/ noun same asfaxfact

fact /f�kt/ noun information pre-sented as real � Temperature changesare an important fact in meteorology. �in (point of) fact in reality, in truthfactor

factor /�f�ktə/ noun 1. an importantpart of a result, a process, etc. � Visibil-ity remains a very important factor inaviation. � critical factor extremelyimportant factor � dominant factormost important factor � safety factorsomething which plays an importantpart in safety 2. � by a factor of quan-tity by which a stated quantity is multi-plied or divided, so as to indicate anincrease or decrease in a measurement �by a factor of ten ten times � The rateis increased by a factor of 10. � conver-sion factor a formula or figure used forconversion of temperatures, distances,etc., from one system to another � Theconversion factor for converting UKgallons to litres is: x 4.546.


93 falsefade

fade /fed/ noun 1. a periodic reduc-tion in the received strength of a radiotransmission � Surface wave at nightcauses fade of the signal. 2. a periodicreduction in braking power � Hardbraking can cause fade and tyre burstthrough overheating. � verb to losestrength, brightness, loudness, or bril-liance gradually � the lights faded thelights became less and less bright, thelights dimmed � the radio signal fadedthe radio signal became weaker andweakerFahrenheit

Fahrenheit /�f�rənhat/ noun a scaleof temperatures where the freezing andboiling points of water are 32° and 212°respectively. Compare Celsius, centi-grade (NOTE: Used in the USA but nowless common in the UK; usually writtenas an F after the degree sign: 32° F.)fail

fail /fel/ verb 1. to stop working prop-erly � the brakes failed the brakes didnot work � the wing failed during ahigh-speed turn the wing broke duringa high-speed turn 2. to receive an aca-demic grade below the acceptable min-imum in an examination or a course ofstudy � the trainee failed his naviga-tion examination the trainee did notpass her navigation exam � without failcertainly, definitely � Be here at 8o’clock without fail.fail safe

fail safe /�fel sef/ noun the principleof designing a structure so that the fail-ure of one part does not affect the safetyof the wholefail safe system

fail safe system /�fel sef �sstəm/noun a system or device which has in-built safeguards against total failure �

The term fail safe means that the struc-ture, though damaged, is capable ofsupporting a reasonable percentage ofits design load.failure

failure /�feljə/ noun 1. a stoppage ora breakdown � bearing failure � Enginefailure is sometimes accompanied byfire. � power failure loss of enginepower, or loss of electrical power sup-ply 2. the fact of not achieving thedesired goal or result � the failure of anexperiment � failure to do somethingnot doing something � The steward’sfailure to remain at his station made the

emergency situation worse. 3. the factof not passing a course, a test, or anexamination � His failure in the GFT(General Flying Test) meant that hedidn’t finish the course.fair

fair /feə/ adjective 1. free of clouds orstorms, clear and sunny � fair weathergood weather 2. just, reasonable, free offavouritism or bias � a fair exam anexam which tested students on whatthey had been taught, was of reasonabledifficulty and duration and which didnot trick the candidates � it is fair tosay that he should have done better itis reasonable to say that he should havedone better � verb to join pieces so as tobe smooth, even, or regular � The air-craft’s wing is faired into the fuselage.fairing

fairing /�feərŋ/ noun a device toimprove the flow of air over a surface �There is a dorsal fairing at the base ofthe fin or vertical stabiliser. � Wheelfairings, called spats, are fitted to lightaircraft to reduce drag. � spat, nacellefairly

fairly /�feəli/ adverb moderately,rather, quite � fairly high levels moder-ately high levels � fairly simple moder-ately simplefall

fall /fɔ�l/ noun 1. a drop or lessening inamount � fall in pressure a drop inpressure 2. the amount of rain or snowwhich comes down at any one time � anovernight fall of snow 3. US autumn �

verb 1. to become less in amount �atmospheric pressure is falling atmos-pheric pressure is decreasing 2. to beincluded within the range of something� Aircraft fall into a number of type cat-egories. � Design methods fall into fourgroups. � Long-range high-frequencycommunications fall in the frequencybracket 2–25 MHz. 3. to drop or comedown freely because of gravity � Lightrain may fall occasionally. 4. to occur ata particular time � New Year’s Day fallson a Thursday this year. (NOTE: falling– fell – fallen)false

false /fɔ�ls/ adjective not true, incor-rect � Lightning may cause false read-ings from sensitive instruments. � falseglide path information incorrect glidepath information


familiar 94familiarfamiliar /fə |�mliə/ adjective 1. oftenseen, common � Clouds are the mostfamiliar visible meteorological feature.2. known � Symbols and abbreviationswhich are strange at present becomefamiliar after a time. � to be familiarwith to have some knowledge of some-thing � He is familiar with the proce-dure.familiarisefamiliarise /fə |�mliəraz/, familiar-ize verb � to familiarise yourself withto get to know something wellfanfan /f�n/ noun a circular device withrotating blades, powered by an engineor motor, for moving a gas such as air �The compressor has large rotating fanblades and stator blades.fanjetfanjet /�t%�bəυf�n/ noun US same asturbofanFANSFANS abbreviation future air naviga-tion systemsFARFAR abbreviation US Federal AviationRegulationfaradfarad /�f�r�d/ noun the SI unit ofcapacitance. Symbol Ffastenfasten /�fɑ�s(ə)n/ verb to secure or toclose, as by fixing firmly in place � fas-ten your seat belt put on and attachyour seat belt � If in-flight conditionsrequire the captain to activate the fas-ten seat belt sign, all cabin serviceceases and cabin crew take up theirassigned seats and strap in.fatiguefatigue /fə |�ti�$/ noun 1. physical ormental tiredness resulting from exertion� Pilot fatigue was a contributing factorin the accident. 2. the weakening or fail-ure of a material such as metal, result-ing from stress � Fan blades must beresistant to fatigue and thermal shock. �Titanium has good fatigue resistance. �fatigue crack crack due to materialfatiguefaultfault /fɔ�lt/ noun a defect in a circuit orwiring caused by bad connections, etc.� A fault in the automatic boost controlunit was repaired.faultyfaulty /�fɔ�lti/ adjective containing afault or defect, imperfect � The faultycomponent was replaced.faxfax /f�ks/ noun 1. an exact copy of adocument, drawing, etc., transmitted

and received by a fax machine con-nected to a telephone link 2. an elec-tronic apparatus linked to a telephoneused to send and receive a fax � Chartsare transmitted by fax to meteorologicaloffices. � CAMFAX � verb to send a fax� Charts are faxed to meteorologicaloffices.FDPSFDPS abbreviation flight data process-ing systemFDRFDR abbreviation flight data recorderFDSFDS abbreviation flight director sys-temfeatherfeather /�feðə/ verb � to feather apropeller to turn the blades of astopped propeller edge on to the airflowin order to reduce drag or wind resist-ance � The feathered position not onlyreduces drag, but also minimises enginerotation, thus preventing any additionaldamage to the engine.featheringfeathering /�feðərŋ/ noun the act ofturning the blades of a stopped propel-ler edge on to the airflow in order toreduce drag � Feathering is accom-plished by moving the pilot’s controllever.feathering gatefeathering gate /�feðərŋ $et/noun a device on the propeller pitchcontrol to prevent unwanted selectionof the feathering positionfeathering positionfeathering position /�feðərŋ pə |

�zʃ(ə)n/ noun a position of the propel-ler pitch control in which the blades arefeatheredfeaturefeature /�fi�tʃə/ noun 1. an important,noticeable or distinctive aspect, quality,or characteristic � Sea breeze is a regu-lar feature of coastal climates. 2. �ground features noticeable, importantobjects in the landscape which are use-ful aids to navigation, e.g. bridges, riv-ers, railway lines, etc. � verb to have asa particular characteristic � Many Rutandesigns feature a canard wing.Federal Aviation AdministrationFederal Aviation Administra-tion /�fed(ə)rəl �evi|�eʃ(ə)n��dmnstreʃ(ə)n/ noun the bodyresponsible for the regulation of avia-tion in the United States � The FAAissues licenses. Abbreviation FAAFederal Aviation RegulationFederal Aviation Regulation/�fed(ə)rəl �evieʃ(ə)n �re$jυ |


95 fine

�leʃ(ə)n/ noun a regulation governingaviation in the United States. Abbrevia-tion FARfeedfeed /fi�d/ noun a supply of fuel,energy, etc. provided for usefeedbackfeedback /�fi�db�k/ noun 1. thereturn of part of the output of a processor system to the input, especially whenused to maintain performance or to con-trol a system � The LC ensures that afeedback signal of the monitored outputfrequency is sent back to the CSDU. 2. afeedback mechanismferryferry /�feri/ verb to make a delivery ofan aircraft by flying it to its operatorfibrefibre /�fabə/ noun a natural or syn-thetic filament like cotton or nylon(NOTE: The US English is fiber.)FICFIC abbreviation flight informationcentrefieldfield /fi�ld/ noun 1. an area of grass onfarmland, in the countryside � In theevent of a power failure, it is importantto select the most suitable field for aforced landing. 2. an imaginary areafield of visionfield of vision /�fi�ld əv �v"(ə)n/noun the area in which something canbe seen without moving the head or theeyesfighterfighter /�fatə/ noun small, single-seator two-seat aircraft for use in militaryconflict � The F16 is an American-builtfighter.figurefigure /�f$ə/ noun 1. a diagram ordrawing � Figure 1 shows a cross-sec-tion of an internal combustion engine.2. a number, especially in mathematicalcalculations � a head for figures goodat figures, arithmetic, accounting, etc. �a two-figure code a code with twonumbers between 0 and 9 3. a form con-sisting of any combination of points orlines, e.g. a trianglefilmfilm /flm/ noun 1. a thin skin or layer� An electrical element made of goldfilm is sandwiched between the layers ofglass. 2. a thin covering or coating �

There is a film of oil between the pistonand cylinder wall.filterfilter /�fltə/ noun 1. a material ordevice through which a liquid or a gas ispassed in order to separate the fluidfrom solid matter or to remove

unwanted substances � fuel filter � oilfilter 2. an electric, electronic, acoustic,or optical device used to reject signals,vibrations, or radiations of particularfrequencies while passing others � Thetuner is a band pass filter which con-fines the bandwidth passed to thereceiver to that required. � verb to passa liquid or gas through a filter in orderto remove unwanted substances � Fuelis filtered before entering the carburet-tor.filter cartridge

filter cartridge /�fltə �kɑ�trd"/noun same as filter elementfilter element

filter element /�fltə �elmənt/ nouna removable paper or metal componentin a filter housing which must bereplaced periodically � From time totime the filter element must be removedand cleaned or replaced. Also called fil-ter cartridgefin

fin /fn/ noun a fixed vertical aerofoil atthe rear of a plane, the vertical stabiliser� The fin provides directional stabilityabout the vertical axis. Also called ver-tical stabiliserfinal

final /�fan(ə)l/ noun the end part of aseries or process � adjective coming atthe end � final assembly the last in aseries of stages of construction of anaircraft when all the pre-assembledparts are put togetherfinal approach

final approach /�fan(ə)l ə|�prəυtʃ/noun 1. a flight path in a direction alongthe extended centre line of the runwayon which a plane is about to land � Theaspect of the runway on final approachhelps the pilot to judge height andprogress. 2. the last stage of an aircraft’sdescent before landing, from when itturns into line with the runway to theprocedures immediately before it landsfine

fine /fan/ adjective 1. of superiorquality, skill, or appearance � a fine daya day when the weather is good � fineweather good weather 2. very small insize, thickness or weight � Cirrus cloudhas a fine, hair-like appearance. � finepowder powder consisting of verysmall particles � fine spray a spray con-sisting of very small drops of liquid 3. �fine wire very thin wire 4. referring tothe pitch or blade angle setting of the


FIR 96

propeller � Fine pitch enables fullengine speed to be used on take-off andcoarse pitch allows an economicalengine speed to be used for cruising.FIRFIR abbreviation flight informationregionfirefire /faə/ noun an area of burning � Toguard against the risk of fire, passen-gers are requested not to smoke in thetoilets. � an engine fire a fire in anengine � verb to shoot a gun, or tolaunch something such as a flare or arocketfire deluge systemfire deluge system /�faə �delju�d"�sstəm/ noun a system which extin-guishes fire by spraying large quantitiesof water on it � A lever actuates the firedeluge system.fire detection systemfire detection system /�faə d|

�tekʃən �sstəm/ noun a system todetect the presence of fire in an aircraftfire extinguisherfire extinguisher /�faər k |

�stŋ$wʃə/ noun a portable device fullof foam, water, powder, etc., for puttingout firesfireprooffireproof /�faəpru�f/ adjectivedesigned to resist the effect of fire � Afireproof bulkhead is provided to sepa-rate the cool area of the engine from thehot area.fire trianglefire triangle /�faə �tra�ŋ$əl/ nounthe illustration of the chemistry of fireas the three sides of a triangle represent-ing fuel, oxygen and heat � If fuel, oxy-gen or heat is removed from the fire tri-angle, combustion will cease.first aid kitfirst aid kit /�f%�st �ed �kt/ noun asmall pack containing plasters, band-ages, antiseptic cream, etc., to be usedin case of an emergencyfirst officerfirst officer /�f%�st �ɒfsə/ noun theofficer who is second-in-command tothe captain of an aircraftFISFIS abbreviation flight informationservicefishtailfishtail /�fʃtel/ verb to move the tailof an aircraft from side to side as a wayof reducing speedFISOFISO abbreviation flight informationservice operatorfitfit /ft/ adjective in good physical con-dition, healthy � Keep fit with diet and

exercise. � noun the exactness withwhich surfaces are adjusted to eachother in a machine � There should be aloose fit between the cylinder and thepiston, the difference being taken up bythe piston rings. � verb 1. to be the cor-rect size and shape for � Oxygen masksshould fit the wearer properly. 2. to puton or attach � Wheel fairings, calledspats, are fitted to some light aircraft toreduce drag. (NOTE: fitting – fitted)fitmentfitment /�ftmənt/ noun an act ofattaching or fixing � Attachment pointsare supplied for the fitment of heavyequipment.fitnessfitness /�ftnəs/ noun the state or con-dition of being physically fit, especiallyas the result of exercise and proper eat-ing habits � The age and physical fit-ness of some passengers can be a limit-ing factor in an evacuation. � fitness tofly description of the physical or mentalcapabilities a person needs to fly an air-craftfixed-wingfixed-wing /�fkst �wŋ/ adjectivereferring to an aircraft that has wingsthat do not move, rather than rotorbladesFLFL abbreviation flight levelflagflag /fl�$/ noun 1. a usually square orrectangular piece of cloth with a sym-bolic design or colour � Flags are flownfrom the signal mast. 2. a small visualwarning or indicating device on the faceof an instrument � There is a warningflag on the instrument if there is a prob-lem.flameflame /flem/ noun the usually yellowarea of burning gases seen when some-thing is burning � Flames were seencoming from number 2 engine.flame arresterflame arrester /�flem ə |�restə/ nouna device to prevent flame from an exter-nal source from entering a fuel tankflame outflame out /�flem �aυt/ verb to ceasefrom some cause other than the shuttingoff of fuel � Air in the fuel line cancause an engine to flame out or stop.flame-outflame-out /�flem aυt/ noun the ceas-ing of combustion in a gas turbineengine from some cause other than theshutting off of fuel (NOTE: The word isalso written flameout.)


97 flight attendantflammable

flammable /�fl�məb(ə)l/ adjectiveeasily ignited and capable of burningfiercely and rapidly, and therefore haz-ardous � Aviation gasoline is a flamma-ble liquid. (NOTE: Flammable andinflammable mean the same thing.)flange

flange /fl�nd"/ noun the outside edgeor rim of a part such as a beam or wheel� The web connects the upper and lowerflanges of a beam.flapflap /fl�p/ noun a movable control sur-face on the trailing edge of an aircraftwing, used primarily to increase lift anddrag during final approach and landing� Flaps should be retracted immedi-ately after landing to decrease lift andtherefore increase brake effectiveness. �cowl

COMMENT: Flaps are not usually usedfor take-offs in light aircraft exceptwhen a short take-off run is required.Flaps are not primary control surfacesof an aircraft.

flareflare /fleə/ noun 1. a stage of the flightimmediately before touchdown whenthe nose of the aircraft is raised into thelanding attitude � The approach, flareand landing can be carried out by auto-matic systems. 2. a small rocket-likedevice with a bright light, for attractingattentionflash

flash /fl�ʃ/ noun giving off light insudden or periodic bursts � Lightning isaccompanied by a brilliant flash. � Lossof vision may occur due to lightningflashes especially at night. � verb 1. togive off light in regular bursts � warn-ing lights flash warning lights go onand off rapidly 2. to appear or to happensuddenly � The image flashed onto thescreen.flash point

flash point /fl�ʃ pɔnt/ noun tem-perature at which fuel vapour or oilvapour will burst into flameflatflat /fl�t/ adjective 1. having a hori-zontal surface without a slope, tilt orcurvature � It has been shown that theflat chart misrepresents the globe-shaped earth. � flat country countrywith no hills or mountains 2. having noair inside � The flat tyre had to bechanged because it had a puncture. 3.electrically discharged or with no elec-

trical charge left in it � The enginewouldn’t start because the battery wasflat.flat spinflat spin /�fl�t �spn/ noun a descentin small circles by an aircraft flying in anearly horizontal positionflattenflatten /�fl�t(ə)n/, flatten out verb tomake flat � As altitude increases, thecountryside appears to flatten out. �

The Earth is spherical in shape but it isflattened at the poles.flawflaw /flɔ�/ noun an imperfection in amaterial, often hidden, that may be anindication of future structural failure �flaw detection a process or system bywhich small weaknesses in metal struc-tures are foundflewflew /flu�/ � flyflexibilityflexibility /�fleks |�blti/ noun 1. theamount or extent to which somethingcan be bent or flexed � Wing structuresmust have flexibility in order to absorbsudden changes in loading. 2. the extentto which a system or device can changeor respond to a variety of conditions orsituations � The more reliable and quickfly-by-wire system allows a muchgreater degree of flexibility with aircraftstability. Opposite rigidityflexibleflexible /�fleksb(ə)l/ adjective 1. notrigid, not stiff � flexible pipes pipesmade of soft material such as rubber orplastic 2. capable of responding to avariety of conditions or situations;adaptable � AC electrical energy ismore flexible and more efficient thanDC. Opposite rigidflierflier /�flaə/ noun 1. the pilot of an air-craft 2. a passenger on an aircraftflightflight /flat/ noun 1. the motion of anobject in or through the Earth’s atmos-phere or through space 2. the distancecovered by a body, e.g. an aircraft, as itflies through the atmosphere � Theflight from London to Paris took 55 min-utes. 3. a scheduled airline journey �

Passengers for flight GF 008 to Ammanshould proceed to gate number 4.flight attendantflight attendant /�flat ə|�tendənt/noun a member of the flight crew wholooks after passengers, serves food, etc.� If you need something, press the callbutton and a cabin attendant will


flight bag 98

respond within a few minutes. Alsocalled cabin attendantflight bagflight bag /�flat b�$/ noun a bagused by flight crew to carry manuals,documents, headset, etc.flight-briefing roomflight-briefing room /�flat �bri�fŋru�m/ noun a room where instructorstalk to trainees immediately before atraining flight or where a pilot talks tohis or her crew immediately beforeboarding the aircraftflight crewflight crew /�flat kru�/ noun airlinestaff responsible for flying the aircraftflight data recorderflight data recorder /�flat �detə r |

�kɔ�də/ noun an electronic devicelocated in the tail section of an aircraftthat picks up and stores data about aflight. Abbreviation FDR. Also calledblack box (NOTE: It is often called theblack box, although it is not black.)flight deckflight deck /�flat dek/ noun a placewhere the flight crew of an airliner sitwhile flying the aircraftflight deck instrumentsflight deck instruments pluralnoun instruments used by the flightcrew when flying an aircraftflight engineerflight engineer /�flat �end"nə/noun the member of the crew of a planewho is responsible for checking that itssystems, including the engines, performproperlyflight envelopeflight envelope /�flat �envələυp/noun same as envelopeflight information regionflight information region /�flat�nfə |�meʃ(ə)n �ri�"ən/ noun airspacewith defined limits which has an airtraffic control information and alertingservice. Abbreviation FIRflight levelflight level /�flat �lev(ə)l/ noun 1.the level of constant atmospheric pres-sure related to a reference datum of1013.25 mb � FL 250 = 25,000 ft.Abbreviation FL 2. the height at whicha particular aircraft is allowed to fly at aparticular timeflight lineflight line /�flat lan/ noun the areaof an airfield, especially a military air-field, where aircraft are parked, serv-iced, and loaded or unloadedFlight ManualFlight Manual /�flat �m�njυəl/noun same as Pilot’s Operating Hand-book

flight operationsflight operations /�flat�ɒpəreʃ(ə)nz/ plural noun the use ofaircraftflight pathflight path /�flat pɑ�θ/ noun a line,course or track along which an aircraftfliesflight planflight plan /�flat plan/ noun a writ-ten statement that gives details of theflight that a pilot intends to makeflight progress stripflight progress strip /�flat�prəυ$res �strp/ a thin cardboard stripwith information on it about a flight,which is updated by air traffic control-lers as the flight progressesflight simulatorflight simulator /�flat �smjυletə/noun a device or computer programwhich allows a user to pilot an aircraft,showing a realistic control panel andmoving scenes, used as training pro-grammeflight-testflight-test /�flat test/ verb to test theperformance of an aircraft or compo-nent in flightfloatfloat /fləυt/ noun 1. a floating ballattached to a lever to regulate the levelof a liquid in a tank, etc. � float-oper-ated switch a shut-off valve operatedby a float 2. a hollow structure fixedbelow an aircraft that allows it to floaton water. Also called pontoon � verb toremain on the surface of a fluid withoutsinking � Because of the air-tightnature of the fuselage, most large air-craft will float for some time beforesinking.float chamberfloat chamber /�fləυt �tʃembə/noun the part of a carburettor whichhouses the floatfloatplanefloatplane /�fləυtplen/ noun a sea-plane that has hollow structuresattached underneath its wings andsometimes its fuselage on which itfloats so that the main body of the planeis not in contact with the water. Com-pare flying boatflowflow /fləυ/ verb 1. to move or runsmoothly with continuity, as a fluid �

Air flows over the wing surfaces and liftis produced. 2. to circulate � Liquidcoolant flows around the engine. � nouncontinuous movement in a particulardirection � The flow of fuel from the fueltanks to the engines.


99 fogflowmeter

flowmeter /�fləυmi�tə/ noun a devicefor measuring the flow of a liquid or gas� The oxygen flowmeter should blinkonce for each breath.fluctuate

fluctuate /�fl�ktʃuet/ verb to vary orchange irregularly � The magnetic fieldwill fluctuate at the supply frequency.fluid

fluid /�flu�d/ noun a substance whichis not solid, whose molecules movefreely past one another and that takesthe shape of its container � de-icingfluid a liquid for removing icefluorescent

fluorescent /flυə|�res(ə)nt/ adjectivereferring to the emission of electromag-netic radiation of visible light � The flu-orescent penetrant process of flawdetection uses a penetrant containing afluorescent dye which fluoresces inultra-violet light.fly

fly /fla/ verb to move through the air orto cause an aircraft to move through theair in a controlled manner � An aero-plane may not fly over a city below sucha height as would allow it to alight inthe event of an engine failure. � He’slearning to fly. (NOTE: flying – flew –flown) � to fly in formation to fly as agroup which maintains a particular pat-tern or arrangement in the airfly-by-wire

fly-by-wire /�fla ba �waə/ nountechnology which interprets move-ments of the pilot’s controls and, withthe aid of computerised electronics,moves the control surfaces accordingly� Using fly-by-wire technology, thestalling angle cannot be exceededregardless of stick input. � The morereliable and quick fly-by-wire systemallows a much greater degree of flexi-bility with aircraft stability.

COMMENT: Fighters like the GeneralDynamics F16 and large transportaircraft such as the Boeing 777 andAirbus A320 have fly-by-wire systems.

flying

flying /�flaŋ/ noun the act of makingan aircraft move through the air in acontrolled mannerflying boat

flying boat /�flaŋ bəυt/ noun a sea-plane with a body that acts like a boat’shull and allows the plane to float onwater. Compare floatplane

flying conditionsflying conditions /�flaŋ kən|

�dʃ(ə)nz/ plural noun the weather andits suitability for flyingflying controlsflying controls /�flaŋ kən|�trəυlz/plural noun the yoke or control column,rudder pedals and other devices used bythe pilot in order to manoeuvre the air-craftflying fieldflying field /�flaŋ fi�ld/ noun asmall airfield from which light aircraftcan operateflying instructorflying instructor /�flaŋ n|

�str�ktə/ noun a trained person, a pilot,who teaches people how to fly an air-craftfly-pastfly-past /�fla pɑ�st/ noun the flight ofan aircraft or group of aircraft over aplace as a spectacle for people on thegroundFMSFMS /�ef em �es/ abbreviation flightmanagement systemfoamfoam /fəυm/ noun 1. a mass of bub-bles of air or gas in a liquid film � foamfire extinguishers � Airport fire crewscovered the fuselage with foam to con-trol the fire. 2. any of various light,porous, semi-rigid or spongy materialsused for thermal insulation or shockabsorption � Polyurethane foam is usedin packaging.focal pointfocal point /�fəυk(ə)l pɔnt/ nounsame as focusfocusfocus /�fəυkəs/ noun the point atwhich rays of light or other radiationconverge � The focus of a lens is alsocalled the focal point. (NOTE: The pluralform is foci. /�fəυsa/) � to come intofocus to become clearer as through theviewfinder of a camera � verb 1. tomake things such as light rays convergeon a central point � A parabolic reflec-tor focuses the transmission into a nar-row beam. 2. to give an object or imagea clear outline or detail by adjustment ofan optical device � Focus the micro-scope in order to make the image easierto see. 3. to direct toward a particularpoint or purpose � The crew focused alltheir attention on finding a solution tothe problem.fogfog /fɒ$/ noun condensed watervapour in cloud-like masses lying closeto the ground and limiting visibility �


föhn 100

When visibility is less than 1,000 mowing to suspended water droplets inthe atmosphere, the condition is knownas fog. � evaporation fog steam fog �

Evaporation fog is usually confined towater surfaces and adjacent areas ofland.föhn

föhn /f%n/ noun a warm dry wind thatblows down the lee side of a mountain,particularly in the Alps (NOTE: Theword is also written foehn.)foil

foil /fɔl/ noun same as aerofoilfoot

foot /fυt/ noun a unit of length in theUS and British Imperial Systems equalto 12 inches or 30.48 centimetres. Sym-bol ft (NOTE: The plural form is feet; footis usually written ft or ’ after figures:10ft or 10’.)foot-pound

foot-pound /fυt paυnd/ noun theability to lift a one pound weight a dis-tance of one foot. Abbreviation ft-lbforce

force /fɔ�s/ noun 1. the capacity to dowork or cause physical change � theforce of an explosion 2. power usedagainst a resistance � In small aerobaticaircraft, considerable force is neededon the control column when performinghigh-speed manoeuvres. 3. a vectorquantity that produces an accelerationof a body in the direction of its applica-tion (NOTE: We say centrifugal force,but the force of gravity.) � the force ofgravity the natural force of attractionwhich pulls bodies towards each otherand which pulls objects on Earthtowards its centre � verb 1. to use poweragainst resistance � Because of distor-tion to the airframe, the pilot had toforce the door open in order to exit theaircraft. 2. � to force someone to dosomething to use physical or psycho-logical power to make somebody dosomething they otherwise would not do� The hijackers forced the crew to fly toAthens.forced landing

forced landing /�fɔ�st �l�ndŋ/noun an unexpected landing that a pilotof an aircraft has to make because of anemergency situationforce down

force down /�fɔ�s �daυn/ verb toforce an aircraft to land, usuallybecause of an emergency situation

force-land

force-land /�fɔ�s �l�nd/ verb to landan aircraft before it gets to its destina-tion because of an emergency situation,or land in these circumstancesforces of flight

forces of flight /�fɔ�sz əv �flat/plural noun the aerodynamic forces, lift,drag, weight and thrust, which act on anobject that is travelling though the airfore

fore /fɔ�/ adjective located at ortowards the front � the fore and aft axisof the aircraft the longitudinal axis ofthe aircraft � to come to the fore tobecome important or to start to play aleading role � The jet engine came tothe fore in the late forties. � aftforecast

forecast /�fɔ�kɑ�st/ noun a statementof what is likely to happen in the futureor describing expected events or condi-tions � weather forecast � forecastweather charts charts with informationabout the weather coming to a particu-lar area � verb to estimate or calculateweather conditions by studying meteor-ological information � Rain is forecastfor this afternoon. (NOTE: forecasting –forecast or forecasted)forecast chart

forecast chart /�fɔ�kɑ�st tʃɑ�t/noun same as prognostic chart �

Prognostic or forecast charts are pre-pared, by the central meteorologicaloffice of each region, normally for peri-ods up to 24 hours ahead.form

form /fɔ�m/ noun 1. a document withblanks for the insertion of details orinformation � insurance form � appli-cation form 2. a kind or type � Theground automatic relief valve is a formof discharge valve. � Drizzle is thelightest form of precipitation. 3. theshape of an object � Fluids take on theform of the container in which they arefound. � in the form of a triangle in theshape of a triangle 4. the way in whicha thing exists, acts, or shows itself �

water in the form of ice � fuel in theform of a spray � verb 1. to come intobeing � In some conditions, ice formson the leading edge of the wing. �

Cumulus clouds only form in an unsta-ble atmosphere. 2. to make a shape �

Three points on the chart form a trian-gle. 3. to make up or constitute � The


101 front

classroom and accommodation build-ing form the main part of the college.formation

formation /fɔ�|�meʃ(ə)n/ noun 1. theprocess of coming into being or form-ing � cloud formation the natural pro-duction and development of clouds �ice formation the natural productionand development of ice 2. � to fly information to fly in a group whichmaintains a particular pattern orarrangement in the airformerformer /�fɔ�mə/ adjective having beenin the past � a former military pilot apilot who used to be a military pilot �

noun 1. the first of two things men-tioned 2. a light secondary structure ofthe airframe which gives improvedshape

‘…much has changed in the formerEastern European States, especially interms of aviation operations and training’[Civil Aviation Training]

formula

formula /�fɔ�mjυlə/ noun a mathe-matical rule expressed in symbols � Theformula for calculating speed is D ÷ T= S (where D = distance, T = time andS = speed). (NOTE: The plural form isformulas or formulae.)forward

forward /�fɔ�wəd/ adjective at, near,or belonging to the front � the forwardsection of the aircraft � forward and aftexitsforwards

forwards /�fɔ�wədz/ adverb towardsa position in front � The throttles aremoved forwards for take-off. (NOTE: TheUS English is forward.)fouling

fouling /�faυlŋ/ noun contaminationof the spark plugs with oil or petrol sothat they do not fire correctly � Theengine should be run at a positive idlingspeed to prevent spark plug fouling.four-digit group

four-digit group /�fɔ� �dd"t�$ru�p/ noun four single numbers foundtogetherfour-stroke combustion engine

four-stroke combustion engine/�fɔ� strəυk kəm |�b�stʃ(ə)n �end"n/noun an engine which operates inaccordance with the four-stroke cycle �

Induction, compression, power andexhaust are the four phases of the four-stroke combustion engine.fpm

fpm abbreviation feet per minute

FPPSFPPS abbreviation flight plan process-ing systemframeframe /frem/ noun 1. a structure thatgives shape or support � Early aircraftfuselages were made of a frame coveredby a fabric. 2. an open structure forholding, or bordering � a door or win-dow frameFREDAFREDA � mnemonicfreezefreeze /fri�z/ verb to pass from the liq-uid to the solid state by loss of heat � Insome conditions, rain droplets freezerapidly on striking the aircraft. (NOTE:freezing – froze – frozen)freightfreight /fret/ noun anything otherthan people transported by a vessel orvehicle, especially by a commercial car-rier � Freight holds are usually locatedbeneath the passenger cabins.freighterfreighter /�fretə/ noun an aircraftdesigned to carry freightfrequencyfrequency /�fri�kwənsi/ noun 1. thenumber of times or the rate at whichsomething happens in a given period oftime � The frequency of flights to holi-day destinations increases during thesummer time. 2. the number of repeti-tions per unit time of a complete wave-form, as of an electric current frequency

‘…a Baltimore man adjusted a babyalarm to improve its performance andfound his youngster’s squawks werebeing picked up by incoming aircrafttuned to the local NDB frequency’ [Pilot]

frequency bracketfrequency bracket /�fri�kwənsi�br�kt/ noun a range of frequencies �

VHF communications are allocated thefrequency bracket 118–137 MHz.frequentfrequent /�fri�kwənt/ adjective hap-pening or appearing often � frequentinspectionfrictionfriction /�frkʃ(ə)n/ noun a force thatresists the relative motion or tendencyto such motion of two bodies in contact� Energy is converted to heat throughfriction.frontfront /fr�nt/ noun 1. the forward partor surface � The entrance is at the front.2. the area, location, or position directlybefore or ahead � in front in a forwardposition relative to something else �

Row 23 is in front of row 24. 3. the


frontal 102

mixed area between air masses of dif-ferent temperatures or densitiesfrontal

frontal /�fr�nt(ə)l/ adjective 1. refer-ring to the forward part or surface areaof something � the frontal area � fron-tal surface the boundary between twoair masses 2. of or relating to a meteor-ological weather front � a frontal stormfrontal depression

frontal depression /�fr�nt(ə)l d|

�preʃ(ə)n/ noun an area of low pressurefound together with a weather frontfrontal system

frontal system /�fr�nt(ə)l �sstəm/noun a series of rain-bearing changes inthe weatherfrost

frost /frɒst/ noun a deposit of verysmall ice crystals formed when watervapour condenses at a temperaturebelow freezing � Frost had to be clearedfrom training aircraft which had beenparked outside overnight. � hoarft

ft /fυt/ abbreviation footfuel

fuel /�fju�əl/ noun a substance such asgas, oil, petrol, etc., which is burnt toproduce heat or power � Each wing tankholds 20 gallons of fuel. � A fuel systemincludes tanks, fuel lines, fuel pumps,fuel filters and a carburettor or fuelinjection system.fuel/air mixture

fuel/air mixture /�fju�əl eə�mkstʃə/ noun a combination of fueland air which is ignited in a pistonengine to provide power

COMMENT: Aircraft engines operate atdifferent altitudes and the pilot mustadjust the mixture to produce the mostefficient fuel/air mixture for theatmospheric density.

fuel gauge

fuel gauge /�fju�əl $ed"/ noun aninstrument indicating fuel contentsfuel injection

fuel injection /�fju�əl n|�d"ekʃ(ə)n/,fuel injection system noun system inwhich fuel is sprayed under pressureinto the combustion chamber of anengine

fuel injectorfuel injector /�fju�əl n|�d"ektə/noun an injector that sprays fuel into thecombustion chamber of an enginefuel pumpfuel pump /�fju�əl p�mp/ noun adevice which moves fuel along pipesfrom the tanks to the enginefumesfumes /fju�mz/ plural noun smoke,gas or vapour given off by a substance,often unpleasant or harmful � When thecabin is rapidly and completely filled bysmoke and fumes, passengers will sufferfrom disorientation.functionfunction /�f�ŋkʃən/ noun 1. a spe-cific occupation or role � Rota planningis one of the functions of the chiefinstructor. 2. purpose � Seals perform avery important function in a hydraulicsystem. � The function of the flaps is toincrease lift and drag. � verb 1. to actas, or to serve the purpose of � Theescape slide also functions as a life raft.2. to operate or to work � The systemfunctions well.fundamentalfundamental /�f�ndə|�ment(ə)l/adjective 1. of or relating to the founda-tion or base � the fundamental laws ofaerodynamics 2. central, forming orserving as an essential component of asystem or structure � Electricity is oneof the fundamental types of energy thatexist in nature.fungal growthfungal growth /�f�n$əl �$raυθ/noun a type of organism which livesand multiplies in particular fuels � Fuelcontains chemicals for the inhibition offungal growth.fusefuse /fju�z/ noun a safety device thatprotects an electric circuit from anexcessive current � Circuit breakersperform the same function as a fuse.fuselagefuselage /�fju�zəlɑ�"/ noun the cen-tral body of a plane, to which the wingsand tail assembly are attached andwhich accommodates the crew, passen-gers, and cargo � The fire started in thewing but soon spread to the fuselage.


Gg

g /d"i�/ symbol the acceleration due toEarth’s gravity � abbreviation gramG

G /d"i�/ abbreviation giga-GA

GA abbreviation general aviationgain

gain /$en/ noun 1. an increase �

There is a gain of heat by the Earth dueto solar radiation. � a gain in altitudean increase in altitude 2. an increase insignal power, voltage, or current � Theamplifier boosts the gain of the incom-ing signal. 3. a benefit or advantage �

verb 1. to increase � He failed the testbecause the aircraft gained 100 ft in the360° level turn. 2. to get or obtain � Shegained a pass in her meteorology exam.gale

gale /$el/ noun a very strong windusually blowing from a single direction� Gales are forecast for the area.gallon

gallon /�$�lən/ noun 1. � imperialgallon unit of volume in the BritishImperial System, used in liquid meas-ure and sometimes in dry measure,equal to 4.546 litres � The system deliv-ers fuel at the rate of 100 to 2,000 gal-lons per hour. Abbreviation gal 2. a unitof volume in the US Customary Sys-tem, used in liquid measure, equal to3.785 litresGAMAGAMA abbreviation General AviationManufacturers Associationgamma rays

gamma rays /�$�mə rez/ pluralnoun electromagnetic radiation givenoff by some radioactive substances �

Gamma rays are given off when radio-active material breaks down.gap

gap /$�p/ noun 1. a space betweenobjects or points 2. the difference �

Micro switches have a very small gapbetween make and break. 3. an opening

� The pilot could see the airfieldthrough a gap in the clouds.gasgas /$�s/ noun a state of matter otherthan solid and liquid � Oxygen andnitrogen are gases. � gas turbineengine an engine with a turbine whichis rotated by expanding hot gasesgaseousgaseous /�$�siəs/ adjective relatingto, or existing as a gas � The atmosphereis the gaseous envelope surrounding theearth.gasketgasket /�$�skt/ noun any of a widevariety of seals or packings usedbetween matched machine parts oraround pipe joints to prevent the escapeof a gas or fluid � Seals, gaskets andpacking make a seal by being squeezedbetween two surfaces.gasolinegasoline /�$�səli�n/ noun US a liq-uid made from petroleum, used as a fuelin an internal combustion engineGATGAT abbreviation general air trafficgategate /$et/ noun 1. a device for con-trolling the passage of water or gasthrough a pipe � The waste gate may becontrolled manually by the pilot. � Dur-ing a descent from altitude, with lowpower set, the turbocharger waste gateis fully closed. 2. a circuit with manyinputs and one output that works onlywhen a particular input is received � Alogic gate is almost the same as aswitch. 3. a device to prevent a leverfrom being moved to an incorrect set-ting � It is necessary to move the rpmcontrol lever through a feathering gateto the feathering position.gaugegauge /$ed"/ noun 1. an instrumentfor measuring or testing � temperaturegauge � pressure gauge 2. a unit of


GCA 104

diameter or width � heavy gauge wirethick wire � verb calculate approxi-mately by using the senses � In fog, it isdifficult to gauge horizontal distances.(NOTE: gauging – gauged)GCAGCA abbreviation ground-controlapproachgeargear /$ə/ noun 1. a toothed wheel thatturns with another toothed part to trans-mit motion or change speed or direction2. � valve gear the mechanism foropening and closing valves 3. equip-ment and/or clothing

‘…as pilots, we understand the need for aconvenient way to transport flight gear.That’s why we custom-designed this lineof soft-sided flight bags in a variety ofstyles’ [Advertisement in Pilot]

gearboxgearbox /�$əbɒks/ noun a device toallow changes in the ratio of enginespeed to final drive speed � The auxil-iary power unit (APU) is a small gasturbine engine which is connected to agearbox.GEMGEM abbreviation ground-effectmachinegeneragenera /�d"enərə/ plural of genusgeneralgeneral /�d"en(ə)rəl/ adjective con-cerned with or applicable to a wholegroup of people or things � generaldescription not a detailed description �general principles main ideas � gen-eral purpose switches all-purposeswitches � general weather situationthe overall weather picture without thedetail � as a general rule usually � ingeneral use used a lotgeneral aviationgeneral aviation /�d"en(ə)rəl �evi|

�eʃ(ə)n/ noun all aviation other thancommercial airlines or the military �

The number of GA aircraft stolen isdown sharply since the general aviationcommunity has taken steps to enhancesecurity. Abbreviation GAgeneral flying testgeneral flying test /�d"en(ə)rəl�flaŋ �test/ noun a test of aircraft-han-dling skills for student pilots. Abbrevia-tion GFTgenerategenerate /�d"enəret/ verb 1. tobring into being � In an emergency, itmay be necessary for crew to generate alittle panic in passengers to motivatethem to move. 2. to produce something

such as heat or electricity as a result ofa chemical or physical process � Thepassage of air around the wing gener-ates lift.generationgeneration /�d"enə |�reʃ(ə)n/ noun1. the act or process of creating or mak-ing � generation of ideas the process ofproducing or getting ideas � generationof electricity the production of electric-ity 2. a class of objects derived from anearlier class � a new generation ofcomputers computers which share arecent development in computer tech-nology which separates them as a classfrom earlier computersgeneratorgenerator /�d"enəretə/ noun apower-operated device for making elec-tricity � Starter generators are a combi-nation of a generator and a starterhoused in one unit.genusgenus /�d"i�nəs/ noun a class, group,or family � Various types of cloud aregrouped into ten basic cloud genera.(NOTE: The plural form is genera.)geographicgeographic /d"i�ə|�$r�fk/, geo-graphical /�d"i�ə |�$r�fk(ə)l/ adjectivereferring to geography � a specific geo-graphical area � the north geographicpolegeographygeography /d"i|�ɒ$rəfi/ noun �physical geography the study of theEarth’s surface and its featuresgeometricgeometric /�d"i�ə|�metrk/ adjectivereferring to geometry � A triangle is ageometric figure. � Geometric pitch(US) is the distance which a propellershould move forward in one revolution.geometrygeometry /d"i |�ɒmətri/ noun 1. thestudy of the properties, measurement,and relationships of points, lines,angles, surfaces, and solids � An under-standing of geometry is essential to thestudent of navigation. 2. a configurationor arrangement � the geometry of theengine nacellegeostationarygeostationary /�d"i�əυ |

�steʃ(ə)n(ə)ri/ adjective referring to anobject, such as a satellite in space,which rotates round the Earth at thesame speed as the Earth and is thereforestationary with reference to a point onthe Earth � There are two main types ofsatellite that are used for collection and


105 governor

transmission of meteorological data,polar and geostationary.geostrophic windgeostrophic wind /�d"i�əυstrɒfk�wnd/ noun a wind which blows hori-zontally along the isobars, across thesurface of the earthGFTGFT abbreviation general flying testGHzGHz abbreviation gigahertzgiga-giga- /$$ə/ prefix one thousand mil-lion. Symbol Ggigahertzgigahertz /�$$əh%�ts/ noun a fre-quency of 109 Hertz. Abbreviation GHzgivengiven /�$v(ə)n/ adjective 1. particu-lar, specified, fixed � At high altitudes,less fuel is consumed for a given air-speed than for the same airspeed at alower altitude. 2. � given (that) takinginto account, considering � Given thecondition of the engine, it is surprisingthat it starts.glareglare /$leə/ noun a strong blindinglight � Glare can be caused by diffusereflection of sunlight from the top of alayer of fog.glass fibre reinforced plasticglass fibre reinforced plasticnoun a composite material made ofplastic which is strengthened by glassfibres, used in the manufacture of air-frames and other aircraft components.Abbreviation GRPglideglide /$lad/ verb to fly without power� In the event of an engine failure, it isimportant to have enough altitude to beable to glide clear of houses, people,etc.glidepathglidepath /�$ladpɑ�θ/, glide pathnoun a path followed by the aircraftdown the glide slope � glidepath cov-erage the vertical and horizontaldimensions of the glide slope radiobeamgliderglider /�$ladə/ noun a fixed wing aer-oplane, normally with no power plantpropulsion � Nowadays, gliders areoften made of composite materials.glideslopeglideslope /�$ladsləυp/, glideslope noun the part of the ILS whichprovides a radio beam at an angle ofapproximately 3° to the point of touch-down from the outer marker thus givingthe pilot information about the height ofthe aircraft on final approach

glidinggliding /�$ladŋ/ noun 1. flying in aglider � gliding club association ofmembers who fly gliders as a pastime 2.flying in a powered aircraft with theengine either switched off or idling �

The best gliding speed for the aircraft is75 knots.

COMMENT: On June 24th 1982, aBritish Airways 747 flying from KualaLumpur to Perth lost all power from allfour engines for 13 minutes, yetlanded safely in Jakarta: proof thateven a large aircraft is capable ofgliding.

globalglobal /�$ləυb(ə)l/ adjective world-wide, referring to something related tothe whole Earth � global pressure pat-terns the pressure patterns of the wholeplanetglobal positioning systemglobal positioning system/�$ləυb(ə)l pə |�zʃ(ə)nŋ �sstəm/ nouna satellite-based navigation system.Abbreviation GPSglobeglobe /$ləυb/ noun an object shapedlike a ball � If the Earth were a uniformglobe, the average temperature wouldvary only with latitude.GLONASSGLONASS noun a system of satellitenavigation operated by Russia. Fullform Global Orbiting Navigation Sat-ellite SystemGMTGMT abbreviation Greenwich MeanTimeGNSSGNSS abbreviation global navigationsatellite systemgo-aroundgo-around /�$əυ ə |�raυnd/ noun aclimb into the circuit and manoeuvringinto position for a new approach andlanding � Because the plane was toohigh on the approach, the pilot executeda go-around.governgovern /�$�v(ə)n/ verb to control orlimit the speed, size or amount of some-thing � The size and number of valvesrequired for a particular type of aircraftis governed by the amount of air neces-sary for pressurisation and air condi-tioning. � The type of undercarriage fit-ted to an aircraft is governed by theoperating weight.governorgovernor /�$�v(ə)nə/ noun a devicefor controlling or limiting the speed sizeor amount of something � Overspeed-


gph 106

ing of the engine is prevented by a gov-ernor in the fuel system. � valvegphgph /�d"i� �pi� �etʃ/ abbreviation gal-lons per hourGPSGPS abbreviation global positioningsystemGPWSGPWS abbreviation ground proximitywarning systemGRGR abbreviation hailgradegrade /$red/ noun 1. a position in ascale of size or quality � Kevlar 49 is thegrade used in aircraft composites. 2. amark indicating a student’s level ofaccomplishment � Students who scoredbelow a particular grade in the exami-nations were not allowed to continuethe course.gradientgradient /�$rediənt/ noun the rate atwhich a quantity such as temperature orpressure changes relative to change in agiven variable, especially distance �

Because there is a temperature gradientacross each front it is possible to drawisotherms which reduce in value fromwarm to cold air. � A pressure gradientoccurs aloft from land to sea.gradualgradual /�$r�d"uəl/ adjective hap-pening slowly but continuously � Lossof cabin pressure may be gradual ratherthan sudden. � gradual change achange which takes place over a periodof timegraduategraduate /�$r�d"u |�et/ verb 1. to begranted an academic degree or diploma� She graduated from Oxford Univer-sity with a first class honours degree. 2.to advance to a new level of skill,achievement, or activity � After 50hours of flying the single engine trainer,the student pilots graduate to flying thetwin engine aircraft. 3. to divide intomarked intervals, especially for use inmeasurement � A thermometer has ascale graduated in degrees Celsius.gramgram /$r�m/ noun a unit of measure-ment of weight, equal to one thousandthof a kilogram. Symbol ggraphgraph /$rɑ�f/ noun a diagram thatshows a relationship between two setsof numbers as a series of points oftenjoined by a line � The graph shows therelationship between lift and drag atvarious airspeeds.

graphic

graphic /�$r�fk/ adjective 1. �graphic solution a technique of usinggeometric constructions to solve prob-lems � One side of the calculator has amoveable slide which is used for thegraphic solution of triangle of velocitiesproblems. 2. described in vivid detail �

The eye witness provided a graphicdescription of the events leading to theaccident. � noun a picture used in acomputer application � The instructor’sworksheets were greatly improved bythe incorporation of graphics to aidcomprehension of the subject matter.grasshoppergrasshopper /�$rɑ�shɒpə/ noun alight, unarmed military aeroplane usedfor reconnaissancegraticulegraticule /�$r�tkju�l/ noun 1. aseries of fine lines in an optical instru-ment such as a telescope, used formeasuring 2. the network of linesformed by the meridians and parallelsof longitude and latitude of the Earth ona flat sheet of paper � A graticule oflines of latitude and longitude is imag-ined to cover the Earth.gravitygravity /�$r�vti/ noun 1. a naturalforce of attraction which pulls bodiestowards each other and which pullsobjects on Earth towards its centre � Inorder for an aeroplane to fly, lift mustovercome the force of gravity. 2. seri-ousness � Throughout the crisis causedby the engine failure, the passengerswere unaware of the gravity of the situ-ation.gravity feedgravity feed /�$r�vəti fi�d/ noun afeed which uses the force of gravity tomove the fuel from the tank to the car-burettorgreat

great /$ret/ adjective 1. large in size,quantity, number, etc. � great distanceslong distances � a great deal of moneya large sum of money � great impor-tance enormous importance 2. verygood, enjoyable or excitingGreenwich Mean Time

Greenwich Mean Time /�$rentʃ�mi�n �tam/ noun local time on theGreenwich Meridian. AbbreviationGMT

COMMENT: GMT is now calledCoordinated Universal Time (UTC)and is also known as Zulu time. UTC is


107 guard

expressed in 24-hour format; forexample, 7:00 P.M. is 1900 hours(say: nineteen hundred hours).

gridgrid /$rd/ noun 1. a pattern of equallyspaced vertical and horizontal lines,sometimes used on a map � Grid linesfacilitate the quick location of a point ofreference. 2. a metal cylinder in a cath-ode ray tube 3. a pattern of equallyspaced vertical and horizontal metalrods or bars � Lead-antimony alloy gridplates are components in a lead-acidbattery.groundground /$raυnd/ noun the solid sur-face of the earth � Hail being muchdenser and heavier than snow, falls at amuch faster rate and can reach theground even with the 0° isotherm at10,000 ft. � verb 1. to prohibit an air-craft or member of an aircrew from fly-ing � The pilot was grounded after fail-ing a medical examination. 2. US toconnect an electrical circuit to a posi-tion of zero potential � While refuellinga light aircraft it is important to groundthe airframe to prevent sparking causedby static electricity. (NOTE: To earth ispreferred in British English.)ground crewground crew /�$raυnd kru�/ noun ateam of employees who service andmaintain the aircraft while it is on thegroundground-effect machineground-effect machine /�$raυnd |

�fekt mə |�ʃi�n/ noun a hovercraft.Abbreviation GEMground elevationground elevation /�$raυnd�eləveʃ(ə)n/ noun the vertical dis-tance, in feet, of the ground above sealevelground instructorground instructor /�$raυnd n |

�str�ktə/ noun a trained person whoteaches support subjects such as mete-orology in a classroomgroundlinggroundling /�$raυndlŋ/ noun amember of the ground crew at an airportor air force baseground loopground loop /�$raυnd lu�p/ noun asharp unplanned turn made by an air-craft that is taxiing, taking off, or land-ing, caused by unbalanced dragground movementground movement /�$raυnd�mu�vmənt/ noun a manoeuvre such astaxiing carried out by an aircraft while

on the ground, or any movement on anairfield by people or surface vehiclesground positionground position /�$raυnd pə|

�zʃ(ə)n/ noun the point on the surfaceof the Earth immediately beneath theaircraftground proximity warning systemground proximity warning sys-tem /�$raυnd prɒk |�smti �wɔ�nŋ�sstəm/ noun a system in aircraftwhich warns pilot, by means of an audi-ble signal, that the aircraft is below apreset height. Abbreviation GPWSground-running operationground-running operation/�$raυnd �r�nŋ �ɒpə |�reʃ(ə)n/ noun aprocedure of running the engine whilethe aircraft is stationary on the groundto check engine performanceground signalground signal /�$raυnd �s$n(ə)l/noun a visual signal displayed on an air-field to give information about localtraffic rules to aircraft in the airground speedground speed /�$raυnd spi�d/ nounthe speed of the aircraft in relation tothe ground over which it is flying.Abbreviation GS, G/Sground temperatureground temperature /�$raυnd�temprtʃə/ noun the temperaturerecorded by a thermometer placed atground levelground visibilityground visibility /�$raυnd�vzblti/ noun horizontal visibilitynear the surface of the earthgroupgroup /$ru�p/ noun 1. a number ofindividual items or people broughttogether because of similarities 2. a col-lection of letters, numbers or symbolsused in weather forecasting, etc.growthgrowth /$rəυθ/ noun an increase insize, number, amount, etc. � the growthof ice crystals � the growth of air travelGRPGRP abbreviation glass fibre rein-forced plasticGSGS, G/S abbreviation ground speedguardguard /$ɑ�d/ noun 1. a device to pre-vent injury or loss, etc. � The thermo-couple probes consist of two wires ofdissimilar metal that are joinedtogether inside a metal guard tube. 2. aperson who protects or keeps watch � asecurity guard � verb to protect fromharm by watching over � to guardagainst to take steps to ensure that


guidance 108

something does not happen � To guardagainst the risk of fire, passengers arerequested not to smoke in the toilets.guidanceguidance /�$ad(ə)ns/ noun 1. help-ful advice � Guidance is provided toassist people in filling in the form. � Thebooklet contains guidance on the advis-ability of flying with a cold. 2. the actionof giving directions to an aircraftguidance systemguidance system /�$ad(ə)ns�sstəm/ noun a system which providessignals to the flight control system forsteering the aircraftguideguide /$ad/ noun something thatdirects or indicates � rough guide asimple explanation to help a person tofind his or her own way through morecomplex information � verb to direct orto indicate � If there is smoke in thecabin, clear commands from the crewwill help to guide passengers to theemergency exits.gustgust /$�st/ noun a strong, sudden rushof wind � a gust of 30 feet per second �On final approach, the pilot must beprepared to counteract the effect ofgusts in order to maintain a smoothdescent along the extended centreline ofthe runway. � gust load an increasedload to the airframe caused by a suddenincrease in wind strength � verb toincrease in strength suddenly � Wind isat 10 knots gusting to 20 knots.gyrogyro /�d"arəυ/ noun same as gyro-scopegyro-gyro- /�d"arəυ/ prefix gyroscopicgyrocompassgyrocompass /�d"arəυ |�k�mpəs/noun a compass which uses gyroscopicdirectional stability rather than magnet-ism to indicate direction � The gyro-compass should be checked against the

magnetic compass and reset if neces-sary.gyroplanegyroplane /�d"arəυplen/ noun anaircraft fitted with an unpowered rotorfor producing liftgyroscope

gyroscope /�d"arəskəυp/ noun adevice consisting of a spinning wheel,mounted on a base so that its axis canturn freely in one or more directions andthereby maintain its own direction evenwhen the base is moved � The tradi-tional attitude indicator, heading indi-cator and turn-coordinator containgyroscopes. � directional (NOTE: Theword is often shortened to gyro.)

COMMENT: A spinning gyro maintainsits position even when an aircraftbanks, climbs, or dives. Gyros drivethe attitude indicator, directionindicator and turn coordinator to helppilots control an aircraft while flying incloud or in poor visibility.

gyroscopicgyroscopic /�d"arə|�skɒpk/ adjec-tive referring to a gyroscope or using theproperties of a gyroscopegyroscopic compass

gyroscopic compass/�d"arəskɒpk �k�mpəs/ noun a com-pass which uses gyroscopic directionalstability rather than magnetism to indi-cate directions. Also called gyrocom-passgyroscopic precessiongyroscopic precession/�d"arəskɒpk pri|�seʃ(ə)n/ noun acharacteristic of a gyroscope, that theforce applied to a spinning gyroscopewill act at a point 90° in the direction ofrotation, not at the point where the forceis applied � Forces of gyroscopic pre-cession act on the direction indicator tokeep it aligned vertically and horizon-tally.


Hhailhail /hel/ noun precipitation as smallpellets of ice � Precipitation is the fall-ing of water, as rain, sleet, snow or hailonto the surface of the earth. �

Although hail, and in particular, heavyhail is rare and of short duration, dam-age to an aircraft may be severe.

COMMENT: In weather reports andforecasts, hail is indicated by theabbreviation ‘GR’.

hailstonehailstone /�helstəυn/ noun a smallpellet of ice which falls from clouds � Ahailstone starts as a small ice particlein the upper portion of a cumulonimbuscloud.hailstormhailstorm /�helstɔ�m/ noun a storm,where the precipitation is hail instead ofrain or snow � Flying through the hail-storm damaged the leading edges.hand flyinghand flying /�h�nd �flaŋ/ noun fly-ing an aircraft by moving the flight con-trols with the hands rather than by usingthe autopilothand-heldhand-held /�h�nd held/ adjectivepossible to hold in the hand � Nowa-days, headsets are usually used in pref-erence to hand-held microphones. �

holdhandlehandle /�h�nd(ə)l/ noun a device forholding, or being operated, by the hand� a door handle � a fire control handle� verb 1. to touch with the hands �

Cabin staff should not handleunwrapped food which is to be served topassengers. 2. to move or operate byhand � The student pilot handled theaircraft well in the turbulent conditions.3. to deal with, or to manage � Flightcrew must be able to handle any emer-gency when it occurs.

handlinghandling /�h�ndlŋ/ noun 1. the actof touching with the hands 2. the use ofthe hands to move or operate something� aircraft handling the act of manoeu-vring the aircraft in the desired manner3. the act of dealing with or managingsomething � Her handling of a difficultsituation won the admiration of thewhole crew.hand luggage

hand luggage /�h�nd �l�$d"/ nounsmall bags that passengers can takewith them into the cabin of an aircraft �The amount of hand luggage is limitedto one bag.hand signals

hand signals /�h�nd �s$n(ə)lz/ plu-ral noun same as marshalling signalshands off

hands off /�h�ndz �ɒf/ adjective,adverb where the operator does notcontrol the operation, which is auto-matic � Automatic flight control systemcapable of landing an aircraft handsoff.hangar

hangar /�h�ŋə/ noun a large shelterfor housing and maintaining aircraft �

Light aircraft should be left with park-ing brakes off so that they can be movedquickly in the event of a fire in thehangar.hard landing

hard landing /�hɑ�d �l�ndŋ/ nounan uncontrolled landing by an aircraftthat results in its being damaged ordestroyedHASELL

HASELL � mnemonichaul

haul /hɔ�l/ noun � long-haul, short-haulhazard

hazard /�h�zəd/ noun a possible dan-ger � Thunderclouds are of specialinterest to aircrew because of the haz-ards they may pose to aircraft in flight.


hazardous 110hazardoushazardous /�h�zədəs/ adjective pos-sibly risky or dangerous � Flying overmountainous terrain can be hazardous.� Structural icing is a hazardous phe-nomenon for rotary wing as well asfixed wing aircraft.hazehaze /hez/ noun dust or smoke in theatmosphere � Haze can seriouslyreduce air-to-ground visibility.headhead /hed/ noun 1. the top part of thebody above the shoulders 2. a person �head count an easy way of countinglarge numbers of people 3. a main endpart or top of something 4. a leader,chief or director � head of departmentthe most senior person in the depart-ment � verb to fly in a particular direc-tion � head north to fly towards thenorthheadingheading /�hedŋ/ noun the directionin which the longitudinal axis of the air-craft is pointing, expressed in degreesfrom north

COMMENT: Wind affects an aircraft inflight, therefore heading does notalways coincide with the aircraft’strack. The pilot must head the aircraftslightly into the wind to correct for drift.

heading bugheading bug /�hedŋ b�$/ noun amovable plastic marker on the horizon-tal situation indicatorheading correctionheading correction /�hedŋ kə |

�rekʃ(ə)n/ noun a change of heading inorder to deal with a new situation. Alsocalled course correctionheading indicatorheading indicator /�hedŋ�ndketə/ noun an instrument whichgives course or direction informatione.g. a horizontal situation indicator(HSI) or direction indicator (DI)

COMMENT: The heading indicator isdriven by a gyro and provides steady,exact indications of heading.

heading to steerheading to steer /�hedŋ tə �stə/noun a gyro-compass point in which todirect the aircrafthead-onhead-on /�hed �ɒn/ adjective, adverb� to approach head-on to approachfrom opposite directionshead-on collisionhead-on collision /�hed ɒn kə |

�l"(ə)n/ noun a collision between twothings or vehicles coming from oppo-site directions

headphonesheadphones /�hedfəυnz/ nounsmall speakers with padding, worn overa person’s ears, used for private listen-ing � Headphones are used to monitorthe signal.headsetheadset /�hedset/ noun headphoneswith a microphone attached, used forRT communications � Headsets areusually used in preference to hand-heldmicrophones.head-up displayhead-up display noun a cockpit sys-tem where data from flight instrumentsis projected onto a screen or the wind-screen so that the pilot can see it with-out having to look down. AbbreviationHUDheadwindheadwind /�hedwnd/ noun a windwhich is blowing in the opposite direc-tion to the direction of movement orflight. Compare tailwind (NOTE: Theword is also written head wind.)headwind componentheadwind component /�hedwndkəm |�pəυnənt/ noun one of the threepossible components of a wind, theother two being crosswind and tailwindheapheap /hi�p/ noun a group of thingspiled or thrown one on top of anotherheap cloudheap cloud /�hi�p klaυd/ noun sameas cumulus cloudheatheat /hi�t/ noun warmth, being hot �

The heat generated by combustion isconsiderable. � verb to make warm orwarmer � The air leaving the turbo-charger is very warm and can be used toheat the cabin.heaterheater /�hi�tə/ noun a device for heat-ing � Pitot heads contain heater ele-ments to prevent icing.heatingheating /�hi�tŋ/ noun the process ofmaking something warmer � the heat-ing action of the sun � kineticheavier-than-airheavier-than-air /�heviə θən �eə/adjective weighing more than the air itdisplaces, and so needing power to flyheavyheavy /�hevi/ adjective having a lot ofweight � a heavy load a load of greatweight � heavy rain rain which is denseand distributes a lot of water over thesurface of the Earth in a relatively shorttimeheavy-dutyheavy-duty /�hevi �dju�ti/ adjectivereferring to something designed for


111 hill

hard wear or use � a heavy-duty battery� Longerons are heavy-duty steel mem-bers.heavy landingheavy landing /�hevi �l�ndŋ/ nouna routine landing in which the aircraftmakes contact with the surface withmore force than usual, thereby possiblycausing damage to the undercarriage �

The pilot reported a heavy landing.hedgehophedgehop /�hed"hɒp/ verb to fly atvery low height above the groundheightheight /hat/ noun the vertical dis-tance of a point, level or object meas-ured from a particular point, e.g. sealevel � Pressure decreases with increas-ing height. � height of the aircraft thevertical distance, measured in feet, ofthe aircraft above the surface of theearthheldheld /held/ � holdheliheli /�heli/ noun a rotary-wing aircraftheliborneheliborne /�helibɔ�n/ adjective trans-ported by helicopterhelicopterhelicopter /�helkɒptə/ noun an air-craft with one or more rotors rotatingaround vertical axes which provide liftand control � Helicopter operations arecarried out at the airport.helicopter rotorhelicopter rotor /�helkɒptə �rəυtə/noun two or more rotating blades,known as the main rotor, which providelift and thrust for a helicopter;helideckhelideck /�helidek/ noun a deck onsomething such as a ship or offshore oilplatform that is used as a landing areafor helicoptersheliographheliograph /�hi�lə|�$rɑ�f/ noun aninstrument with a mirror to send mes-sages by reflecting the sun � Helio-graphs enable reflected sunlight to bedirected to a ship or aircraft in periodsof direct sunlight.helipadhelipad /�helip�d/ noun an areawhere helicopters take off and landheliportheliport /�helipɔ�t/ noun an airportdesigned for helicoptershelistophelistop /�helistɒp/ noun a placewhere helicopters can take off and land,but usually one that does not have thesupport facilities found at a heliporthelohelo /�hi�ləυ/ noun 1. a rotary-wingedaircraft 2. same as heliport

hemispherehemisphere /�hemsfə/ noun half asphereHertzHertz /h%�ts/ noun the SI unit of fre-quency, defined as the number of cyclesper second of time. Abbreviation HzHFHF abbreviation high frequencyhighhigh /ha/ adjective 1. having greatvertical distance � a high mountain 2.great, large, a lot � high engine rpmfast engine speed � high pressure a lotof pressure � high reliability good reli-ability � high speed a fast speed � hightemperature a hot temperature � nounan area of high atmospheric pressure �

There is a high over the British Isles.high frequencyhigh frequency /�ha �fri�kwənsi/,high frequency band /�ha�fri�kwənsi �b�nd/ noun a radio com-munications range of frequenciesbetween 3–30 MHz. Abbreviation HFhigh-performancehigh-performance /�ha pə|

�fɔ�məns/ adjective a system whichprovides better-than-usual output � anengine with a high performance � Somehigh-performance engines have coolantand oil system thermostats which aidwarming-up.high performance aircrafthigh performance aircraft /�hapə|�fɔ�məns �eəkrɑ�ft/ noun an aircraftcapable of flying faster, higher or withmore manoeuvrability than normal air-crafthijackhijack /�had"�k/ verb to take overcontrol of an aircraft by one or severalunauthorised person or persons with theintention of forcing the crew to fly it toa different destination � The airlinerwas hijacked on its way to Paris.hijackerhijacker /�had"�kə/ noun a personwho hijacks an aircraft or other vehiclehijackinghijacking /�had"�kŋ/ noun the actof taking over control of an aircraft byone or several unauthorised person orpersons with the intention of forcing thecrew to fly it to a different destination �The crew must be alert at all times to thepossibility of hijacking, bombs andstowaways.hillhill /hl/ noun an easily-seen, naturalelevation, smaller than a mountain �

Slopes on the side of a hill or mountainfacing away from the sun receive lessintense radiation. � Hill shading is pro-


hinder 112

duced by assuming that bright light isshining across the chart sheet so thatshadows are cast by the high ground.hinder

hinder /�hndə/ verb to make it diffi-cult for something to happen � Freeflow of fuel may be hindered by a block-age in the fuel line. � Her illness hin-dered his progress on the course.hinge

hinge /hnd"/ noun a device whichallows a door, flap or lid to open andclose on a stationary frame � Flyingcontrol hinges should be inspectedbefore flight. � verb to move against astationary frame � Access to the enginecompartment is normally via hingedcowling panels.HIRF

HIRF abbreviation high-intensity radi-ated fieldsHMR

HMR abbreviation helicopter mainroutehoar

hoar /�hɔ�/, hoar frost noun a frozendew which forms on outside surfaceswhen the temperature falls below freez-ing point � Rapid descent from coldaltitudes into warm moist air may pro-duce hoar frost on the aircraft.hold

hold /həυld/ noun an area or compart-ment within the aircraft for carryingfreight � Carry-on baggage is limitedby regulations as to size and weight anditems in excess of this should be stowedin the luggage hold. � verb 1. to keepand prevent from moving � The func-tion of the autopilot system is to holdthe aircraft on a desired flight path bymeans of gyroscopes and/or accelerom-eters. � If the operating pressure falls orfails, a mechanical lock holds thereverser in the forward thrust position.2. to keep an aircraft in a particularposition on the ground or in the airwhile waiting for further clearance fromair traffic control � It is normal practicefor ATC to hold taxiing aircraft wellclear of the glide path and localiserantenna when visibility is poor. 3. tohave and keep in the hand � Hold themicrophone in your right hand. � hand-held possible to hold in the hand �

Nowadays, headsets are usually used inpreference to hand-held microphones.4. to have (NOTE: holding – held) � he

holds an IMC rating he has an IMCratingholderholder /�həυldə/ noun 1. a device forholding something � a holder for a fireextinguisher 2. a person who has a par-ticular title or qualification � a holder oftwo awards for distinguished serviceholding fuelholding fuel /�həυldŋ �fju�əl/ nounextra fuel carried by an aircraft to allowfor time spent in the hold waiting for airtraffic control clearanceholding patternholding pattern noun a racetrack-shaped flight pattern with two parallelsides and two turns, flown usually whilean aircraft is waiting for clearance tolandholding pointholding point /�həυldŋ pɔnt/ noun1. a particular location, in the air or onthe ground where aircraft spend time,waiting for further clearance from airtraffic control 2. a place, often desig-nated Alpha, Bravo, Charlie, etc., whereaircraft wait before entering the runway,as instructed by air traffic controlholding stackholding stack /�həυldŋ st�k/ anarea of airspace where planes areinstructed to wait before landing if thereare delays (NOTE: Aircraft circle anddescend according to the controller’sinstructions until they are released fromthe lowest height in the stack for theirfinal approach to the airport.)hollowhollow /�hɒləυ/ adjective having aspace within, not solid � a hollow driveshaft Opposite solidhomehome /həυm/ noun the home airfield �home airfield the airfield which onereturns to after a two-leg flighthomewardhomeward /�həυmwəd/ adjectivegoing towards home � homeward jour-ney � adverb � homeward boundheading towards homehomewardshomewards /�həυmwədz/ adverbtowards home � They were headinghomewards when the accident hap-pened.hominghoming /�həυmŋ/ noun a flighttowards or away from a radio stationwhile using direction finding equip-ment � Where an RBI is fitted, homingto an NDB can be made by initiallyturning the aircraft until the relativebearing is zero.


113 hubhomogeneoushomogeneous /�həυməυ |�d"i�niəs/adjective of the same kind � If the airover a large region were homogeneous,there would be no horizontal differ-ences in surface temperature. � Theatmosphere is not homogeneous – pres-sure, temperature and humidity can allchange with height.hophop /hɒp/ noun a flight or section of aflight in an aircraft (informal )horizonhorizon /hə |�raz(ə)n/ noun the linewhere the sky and the ground appear tojoin � visual horizon a horizon whichcan be seenhorizontalhorizontal /�hɒr|�zɒnt(ə)l/ adjectiveparallel to the horizon, or at right anglesto the vertical � The horizontal motionof air is known as wind.horizontal axishorizontal axis /�hɒrzɒnt(ə)l��kss/ noun a horizontal reference lineof a graph � The plot shows the effect ofairspeed on lift with airspeed shown onthe horizontal axis and lift on the verti-cal axis.horizontal situation indicatorhorizontal situation indicator/�hɒrzɒnt(ə)l �stʃu |�eʃ(ə)n�ndketə/ noun a cockpit instrumentwhich gives the pilot information aboutthe direction of the aircraft’s flight path� On the aircraft, the horizontal situa-tion indicator is located on the instru-ment panel below the attitude indicator.Abbreviation HSI

COMMENT: The horizontal situationindicator combines the function of theheading indicator and a VOR/ILSdisplay.

horizontal stabiliserhorizontal stabiliser/�hɒrzɒnt(ə)l �stebəlazə/ noun atailplane � The horizontal stabiliserprovides stability about the lateral axisof the aircraft.hornhorn /hɔ�n/ noun a device for project-ing sound � warning horn devicewhich emits a loud warning noisehorn balancehorn balance /�hɔ�n �b�l(ə)ns/noun part of a control surface forwardof the hinge line which reduces theforce needed by the pilot to move thesurfacehorsepowerhorsepower /�hɔ�spaυə/ noun theaccepted unit for measuring the rate ofdoing work � Horsepower is defined as

33,000 foot-pounds of work done in oneminute. Abbreviation h.p., HPhosehose /həυz/ noun a long, flexible pipeusually made of fabric, plastic or rubberfor pumping gases or liquids � refuel-ling hose a flexible pipe used to pumpfuel from the bowser to the aircrafthothot /hɒt/ adjective very warm, havinga high temperature � hot weather � hotair air introduced to melt ice forming inthe carburettor in a piston engine air-crafthourhour /aυə/ noun 1. a period of timewhich lasts sixty minutes � It’s a three-hour flight to Greece from London. 2. amethod of indicating time � Flight BA321 landed at Heathrow at 10.30 hours.househouse /haυz/ verb to contain oraccommodate � The areas between theribs in the wings are utilised to housefuel tanks. � The wing tips house thenavigation lights.housinghousing /�haυzŋ/ noun a compart-ment or container � The crankcase isthe housing that encloses the variousmechanical parts surrounding thecrankshaft. � engine housing enginecompartmenthoverhover /�hɒvə/ verb to remain station-ary, relative to the earth, while in the air� noun a period of stationary flight �

During a hover, helicopter pilots mustbe able to coordinate movements ofboth hands and feet.hovercrafthovercraft /�hɒvəkrɑ�ft/ noun avehicle that can travel over land andwater supported on a cushion of air thatis produced by a powerful engine thatblows air downwards. Also called aircushion vehicle, ground effectmachinehowever

however /haυ|�evə/ adverb but � Thewind was gusty, however the landingwas good. � The incident was serious,however she escaped with only a warn-ing.hrshrs abbreviation hoursHSIHSI abbreviation horizontal situationindicatorhubhub /h�b/ noun a major airport whereinternational or long-distance flightstake off and land


hub airport 114hub airporthub airport /�h�b �eəpɔ�t/ nounsame as hubHUDHUD abbreviation head-up displayhuman factorshuman factors /�hju�mən �f�ktəz/noun the study of the way in whichhumans handle, and react to, things intheir environment. It is used in aviationto develop safer systems and proce-dures. (NOTE: Human factors is followedby a verb in the singular.)humidhumid /�hju�md/ adjective contain-ing a lot of water vapour � humidweather weather which, althoughwarm, feels damp and uncomfortablehumidityhumidity /hju�|�mdti/ noun a meas-urement of how much water vapour iscontained in the air � the humidity ishigh there is a lot of moisture or watervapour in the airhydraulichydraulic /ha |�drɔ�lk/ adjectivereferring to any system or device whichuses fluids such as oil to transmit aforce from one place to another usingpipes � a hydraulic pumphydraulic fluidhydraulic fluid /ha|�drɒlk �flu�d/noun thin oil used in hydraulic brakingsystems, etc.

hydraulic pressure

hydraulic pressure /ha|�drɔ�lk�preʃə/ noun the pressure exerted byhydraulic fluidhydraulic tubing

hydraulic tubing /ha|�drɔ�lk�tju�bŋ/ noun system of tubes or thinpipes connecting the main componentsof a hydraulic systemhydro-

hydro- /hadrəυ/ prefix water � ahydro-mechanical governorhygrometer

hygrometer /ha |�$rɒmtə/ noun aninstrument used for the measurement ofhumidity � The most common type ofhygrometer is the wet and dry bulb ther-mometer arrangement.hypoxia

hypoxia /ha |�pɒksiə/ noun a medicalcondition in which not enough oxygenis supplied to the body � The symptomsof hypoxia are sometimes difficult todetect.

COMMENT: Cabin pressurisation oroxygen equipment is usually requiredfor flying at altitudes at or above about10,000 ft (3,048 m).

Hz

Hz abbreviation Hertz


IIASIAS /�a e �es/ abbreviation indicatedairspeedIATAIATA abbreviation International AirTransport AssociationI-beamI-beam /�a bi�m/ a large bar of metalor some other strong substance with across-section shaped like the letter ‘I’ICAOICAO /a |�keəυ/ abbreviation Interna-tional Civil Aviation Organizationiceice /as/ noun frozen waterice crystalice crystal /�as �krst(ə)l/ noun atype of precipitation composed of crys-tals in the form of needles, plates or col-umnsicingicing /�asŋ/ noun a process by whichpart of the aircraft becomes covered inice while in flight � Engine icing can beextremely hazardous to flight. � Air-frame icing can be encountered in wavecloud. � anti-icing, de-icingidealideal /a |�dəl/ adjective perfect, asgood as can be expected or the best pos-sible � an ideal situation a very goodsituation � ideal flying conditions verygood flying conditionsidentident /�adent/ noun a function on thetransponder panel which helps a con-troller to identify the aircraft � The identis suppressed until the standby VOR isfully run-up and has passed its monitorchecks. Full form identityidenticalidentical /a |�dentk(ə)l/ adjectiveexactly the same � identical computerscomputers which are exactly the sameidentificationidentification /a |�dentf |�keʃ(ə)n/noun the process by which a person, air-craft, etc., is recognised � identifica-tion of ground features means bywhich particular features on a chart,

such as railway lines or bridges, arematched with the real feature on thegroundidentification beacon

identification beacon /a|�dentf|

�keʃ(ə)n �bi�kən/ noun an aeronauticalbeacon which gives out a Morse signalwhich enables a pilot to establish theirlocation in relation to the beacon � Civiland military aerodrome identificationbeacons can be distinguished by colour.identifier

identifier /a|�dentfaə/ noun agrouped number/letter code by which aweather station or beacon can be recog-nised � When a TAF requires amend-ment, the amended forecast is indicatedby inserting AMD (amended) after TAFin the identifier and this new forecastcovers the remaining validity period ofthe original TAF.identifyidentify /a |�dentfa/ verb to recog-nise � Crew members can be identifiedby their uniforms. � In conditions ofpoor visibility, it is sometimes difficultto identify ground features.identityidentity /a |�dentti/ noun the nameand details of a person, aircraft, etc. �

The air traffic controllers are trying toestablish the identity of the aircraft. �

identidle

idle /�ad(ə)l/ noun the state of anengine when it is running but not deliv-ering power to move the vehicle or air-craft � verb to turn over slowly withoutproviding enough power to move thevehicle or aircraft � After starting a pis-ton engine from cold, it is good practiceto allow it to idle for a short time beforeopening the throttle wide.idle cut-off

idle cut-off /�ad(ə)l �k�t �ɒf/ noun aposition on the mixture control of a


idle rpm 116

light aircraft which allows the engine tobe shut down without leaving a com-bustible fuel/air mixture in the engineidle rpm

idle rpm /�ad(ə)l �ɑ� pi� �em/ nounthe speed at which a piston engine turnswhen it is not running fast enough tomove the vehicle or aircraft, i.e. on alight aircraft when the throttle is almostclosedidlingidling /�ad(ə)lŋ/ noun a state inwhich the engine is turning over slowlywithout providing enough power tomove the vehicle or aircraftidling speed

idling speed /�ad(ə)lŋ spi�d/ nounthe rpm of the engine when it is idling �After start-up, the engine acceleratesup to idling speed. � Before the engineis stopped, it should normally beallowed to run for a short period atidling speed to ensure gradual cooling.IFIF abbreviation 1. instrument flying 2.intermediate frequencyIFRIFR abbreviation instrument flightrulesignite

ignite /$ |�nat/ verb to burn or causeto burn � The spark plug ignites thefuel/air mixture. � The air/fuel mixtureignites.igniter

igniter /$ |�natə/ noun a device forstarting gas turbine engines � An elec-tric spark from the igniter plug startscombustion.ignitionignition /$ |�nʃ(ə)n/ noun 1. the start-ing of burning of a substance � Satisfac-tory ignition depends on the quality ofthe fuel. 2. the moment, in an internalcombustion engine, when a spark fromthe spark plug causes the fuel/air mix-ture to burn � Ignition should occur justbefore top-dead-centre. 3. an electricalsystem, usually powered by a battery ormagneto, that provides the spark toignite the fuel mixture in an internal-combustion engine � Ignition problemsare a source of many engine failures. 4.a switch that activates the ignition sys-tem � the key is in the ignition the keyis in its position in the ignition lockignition key

ignition key /$|�nʃ(ə)n ki�/ noun akey used to switch on the ignitionignition lock

ignition lock /$|�nʃ(ə)n lɒk/ noun akey-operated switch for activating the

ignition circuit of an aircraft or a vehi-cleilluminate

illuminate /|�lu�mnet/ verb 1. togive light to an otherwise dark area � Aflare illuminates the ground below it. 2.to show a light or become bright � Whenthe aircraft is 5 knots above stallingspeed, a warning lamp illuminates.illumination

illumination / |�lu�m |�neʃ(ə)n/ nounlight � Batteries provide about 20 min-utes illumination for the lamp. � day-light illumination the amount of lightin normal daytime conditionsillustrate

illustrate /�ləstret/ verb 1. to dem-onstrate or explain clearly, often byusing pictures � Contour charts illus-trate the horizontal distribution ofheight above mean sea level. 2. to showas an example � A number of aviationdisasters have illustrated the impor-tance of clear, correct use of languagein R/T (Radiotelephony) communica-tions.illustration

illustration /�lə |�streʃ(ə)n/ noun 1.a picture which explains something �

The illustration on page 23 shows across section of a typical gas-turbineengine. 2. an example � The mechanicsof the föhn wind provide a good illustra-tion of the adiabatic process in action.ILS

ILS abbreviation instrument landingsystemILS glideslope

ILS glideslope /�a el es�$ladsləυp/ noun a radio beam in anILS which gives vertical guidance � Theangle of the glide slope is usually aboutthree degrees to the horizontal. �

glideslopeILS locator beacon

ILS locator beacon /�a el es ləυ |

�ketə �bi�k(ə)n/ noun a non-direc-tional beacon used for final approach �

Power output can be as little as 15 wattsfor an ILS locator beacon.IM

IM abbreviation inner markerimage

image /�md"/ noun a reproduction ofthe form of an object or person �

Although difficult to see, the photo-graph shows the image of the aircraftwith part of the fin missing. (NOTE: Itsuggests that the image has no detailand that it is the shape which is impor-tant.)


117 inactiveimaginaryimaginary / |�m�d"n(ə)ri/ adjectivenot real � The equator is an imaginaryline around the earth.IMC

IMC abbreviation instrument meteoro-logical conditionsimmediateimmediate /|�mi�diət/ adjective 1.happening at once or instantly � Fireextinguishers should be ready for imme-diate use in the event of an emergency.� in the immediate future in the verynear future 2. nearby, close at hand �

The immediate area surrounding theEarth is known as the atmosphere.immerse

immerse /|�m%�s/ verb to cover com-pletely in liquid, to submerge � Fuel ispumped from the main tanks via fullyimmersed booster pumps mounted onthe base of the fuel tank.imminent

imminent /�mnənt/ adjective due tohappen in a very short time � The trans-mission made it clear that the aircraftwas in imminent danger. � A messagefrom the flight deck informs cabin staffthat take-off is imminent.impact

impact /�mp�kt/ noun the striking ofone body against another, a collision �on impact as soon as it hit something �One of the tyres burst on impact (withthe ground). � Super-cooled waterdroplets start to freeze on impact withan aircraft surface.impact resistanceimpact resistance /�mp�kt r |

�zstəns/ noun the ability of a materialto withstand an impactimpair

impair /m |�peə/ verb to cause tobecome less effective � Constant expo-sure to very loud noise impairs thehearing. � The pilot’s vision may betemporarily impaired by lightningflashes. � An incorrect grade of fuelimpairs engine performance.impairment

impairment /m |�peəmənt/ noun alessening of effectiveness � De-icingequipment is used to prevent impair-ment of the lifting surfaces through iceformation.impart

impart /m |�pɑ�t/ verb to give, to passon � A rotating propeller imparts rear-ward motion to a mass of air.impedance

impedance /m |�pi�d(ə)ns/ noun totalelectrical resistance to current flow inan alternating current circuit � Imped-

ance will vary with changes in fre-quency.impedeimpede /m |�pi�d/ verb to hinder orobstruct progress � Hills and mountainsimpede the horizontal flow of air.impellerimpeller /m |�pelə/ noun a rotor usedto force a fluid in a particular directionimportance

importance /m |�pɔ�t(ə)ns/ noun sig-nificance, strong effect or influence �

Upper winds are of great importance inmeteorology. (NOTE: The expressionsof fundamental importance, of greatimportance, of prime importance, ofutmost importance, of vital impor-tance all mean very important.)import dutyimport duty /�mpɔ�t �dju�ti/ nounpayment made to a government on par-ticular goods imported or exported � theduty payable on a carton of cigarettesAlso called customs duty, dutyimposeimpose /m |�pəυz/ verb 1. to forcesomething upon a person or thing � Thetrimmer is used to ease the loadsimposed on the flying controls duringflight. 2. � to impose a fine to requiresomebody to pay a sum of money aspunishment � to impose restrictions toplace limitations on somebody’s actionsimproveimprove /m |�pru�v/ verb to make orbecome better � Turbochargers improveaircraft performance. � The trainee’sflying skills improved a lot in a shortperiod of time.improvementimprovement /m |�pru�vmənt/ nounthe process of becoming better, orsomething that makes a thing better �

An improvement in weather conditionsenabled the flight to depart.impulseimpulse /�mp�ls/ noun a force ofshort duration � A magneto is designedto produce electrical impulses one afteranother at precise intervals, so thateach separate impulse can be used toprovide a spark at a spark plug.impulse magnetoimpulse magneto /�mp�ls m�$|

�ni�təυ/ noun a magneto with a mecha-nism to give a sudden rotation and thusproduce a strong sparkinabilityinability /�nə|�blti/ noun the fact ofbeing unable to do somethinginactiveinactive /n |��ktv/ adjective notswitched on, in a passive state � At the


inadvertent 118

time of the accident the autopilot wasinactive.inadvertent

inadvertent /�nəd|�v%�t(ə)nt/ adjec-tive not intended, not meant, accidental� A safety mechanism prevents inad-vertent retraction of the undercarriagewhile the aircraft is on the ground.inboard

inboard /�nbɔ�d/ adverb closer to thecentre of an aircraft rather than the sidesor edgesinbound

inbound /�nbaυnd/ adverb, adjectivetowards a destination � The aircraft fliesoutbound from the beacon along theairway and inbound to the facility at theother end of the leg. � inbound trafficaircraft flying towards an airfieldincapacity

incapacity /�nkə |�p�sti/ noun theinability to do what is needed, not hav-ing the necessary power to do some-thing � crew incapacity an injury to acrew member which prevents him orher from performing his or her normalduties � Accident research has shownthat crew incapacity greatly increasesthe risk to passengers’ safety.inch

inch /nʃ/ noun a British Imperial Sys-tem unit of length, also used in the US,equal to 25.4 millimetres or 2.54 centi-metres or 1/12 of a foot. Abbreviationin (NOTE: The plural form is inches,usually written in or " with numbers, 5ft6in or 5’ 6". Say five foot six inches.)incidence

incidence /�nsd(ə)ns/ noun the fre-quency of occurrence � The incidenceof structural failure has decreased withthe introduction of modern constructionmaterials and techniques.incident

incident /�nsd(ə)nt/ noun an eventor happening which interrupts normalprocedure � A violent passenger had tobe removed from the aircraft beforedeparture, and details of the incidentwere reported in the local newspapers.

‘…in 1995, a pilot flying above LasVegas was struck by a laser beam andincapacitated for more than two hours. Itwas one of over fifty incidents involvinglasers and aircraft reported in the area thatyear’ [Pilot]

inclination

inclination /�nkl|�neʃ(ə)n/ noun aslope or slant from the horizontal orvertical

inclineincline /n |�klan/ verb to slope or slantfrom the horizontal or vertical, to tilt �

The runway inclines slightly upwards. �noun /�nklan/ a slope or slant � Thereis a steep incline at the end of the run-way.inclinometerinclinometer /�nkl |�nɒmtə/ nounthe lower part of a turn coordinator, inwhich a ball in a sealed curved tubeindicates if a turn is coordinated. Alsocalled rudder ball. � ballincludeinclude /n |�klu�d/ verb to take in as apart, to count along with others � Solidparticles in the atmosphere includedust, sand, volcanic ash and atmos-pheric pollution. � A fuel systemincludes tanks, fuel lines, fuel pumps,fuel filters and a carburettor or fuelinjection system. Opposite excludeinclusiveinclusive /n |�klu�sv/ adjective tak-ing in the extremes in addition to thepart in between � bearings 180° to270° inclusive bearings 180° and 270°are part of the range of bearings men-tionedincomingincoming /�nk�mŋ/ adjectivesomething which is being received, e.g.radio waves or solar radiation � incom-ing transmissions � incoming signal �

There is a fall of temperature untilabout one hour after dawn when incom-ing solar radiation balances outgoingterrestrial radiation. Opposite outgo-ingincorporateincorporate /n |�kɔ�pəret/ verb toinclude as part of something whichalready exists � Some types of outflowvalve incorporate safety valves. �

Warning lamps often incorporate apress-to-test facility.

‘…the instrument panel on the MooneyEncore has been re-engineered toincorporate improvements’ [CivilAviation Training]

incorrectincorrect /�nkə|�rekt/ adjective notcorrect, not right � If the trim position isincorrect, a warning horn will soundwhen number three thrust lever isadvanced.increaseincrease noun /�nkri�s/ a rise to agreater number or degree � Decreasingengine rpm results in an increase in therate of descent. Opposite reduction �


119 inductance

verb /n |�kri�s/ to become greater ormore, to rise � As you increase height,the countryside below you appears toflatten out. Opposite reduce � opposite(all senses) decreaseincrementincrement /�ŋkrmənt/ noun some-thing added � The minimum detectionrange of a pulse radar system is equalto half the pulse length plus a smallincrement.incurincur /n |�k%�/ verb to acquire or toreceive something, often somethingunwanted � Fuel penalties can beincurred if fuel surplus to requirementsis carried. � In some aircraft, the datumshift is operated automatically to caterfor any large trim changes incurred byoperating undercarriage, flaps, etc.(NOTE: incurring – incurred) � toincur a financial loss to lose money, ina business or commercial senseindefiniteindefinite /n|�def(ə)nət/ adjectivewithout limits � an indefinite period oftime a period of time which, in reality,may have no endindependentindependent /�nd |�pendənt/ adjec-tive free from the influence or effects ofother people or things � Airspeed isindependent of wind and is the sameregardless whether the aircraft is flyingupwind, downwind or at any angle tothe wind. � independent system a sys-tem which can operate by itselfindexindex /�ndeks/ noun an alphabeticallist of references to page numbers foundat the end of a book or long document(NOTE: The plural form is indexes orindices /�ndsi�z/ .)index letter

index letter /�ndeks �letə/, indexnumber /�ndeks �n�mbə/ noun a let-ter or number which makes it easier toreference or look up information � Eachobserving meteorological station isshown on the chart as a small circle,identified by its own index number.indicateindicate /�ndket/ verb 1. to show orpoint out � A lamp on the instrumentpanel will indicate when the pump isoperating. � The needle indicated tozero. 2. to serve as a sign or symptom �Black smoke from the exhaust may indi-cate a rich mixture or worn pistonrings.

indicated airspeed

indicated airspeed /�ndketd�eəspi�d/ noun the airspeed shown bythe cockpit or flight-deck instrument �

The aircraft stalls at an indicated air-speed of 50 knots. Abbreviation IASindication

indication /�nd |�keʃ(ə)n/ noun 1.pointing out � Indication of altitude isgiven on the altimeter. 2. a sign orsymptom � A drop in engine rpm is anindication of ice forming in the carbu-rettor. � audible indication a soundwhich serves as a warning, e.g. a bleepindicator

indicator /�ndketə/ noun some-thing which shows informationindividual

individual /�nd|�vd"uəl/ adjectiveexisting as a separate thing � Thehydraulic braking system consists of amaster cylinder with individual brakecylinders at each wheel. � There is amaintenance manual for each individ-ual engine. � noun a separate humanbeing considered as one rather than as amember of a larger group � The instruc-tor regards her trainees as a number ofindividuals rather than a group.induce

induce /n |�dju�s/ verb to bring about,to cause to happen � If a coil carrying achanging current is placed nearanother coil, the changing magneticfield cuts the other coil and induces avoltage in it. � Unequal deposits onmoving parts can induce severe vibra-tion especially on propellers and heli-copter rotors.induced drag

induced drag /n|�dju�st �dr�$/noun part of total drag, created by lift �There are two basic types of drag,induced drag and parasite drag.

COMMENT: Induced drag is createdwhen high-pressure air below a wingrotates around the tip to the low-pressure area above and increases asairspeed decreases and angle ofattack increases.

inductance

inductance /n |�d�ktəns/ noun ameasure of a conductor’s ability tobring a voltage into itself when carryinga changing current, e.g. during shorttimes when the circuit is switched on oroff � At low frequencies, the rate of col-lapse of the magnetic field will be slowand the inductance will be low.


induction 120induction

induction /n |�d�kʃən/ noun 1. theprocess by which the fuel/air mixture isdrawn into the cylinders of an internalcombustion engine � The four strokes ofthe engine are induction, compression,combustion and exhaust. 2. the produc-tion of electrical current in a conductorby a change of magnetic field � A trans-former is a static device that changesthe amplitude or phase of an alternat-ing voltage or current by electro-mag-netic induction.inductive

inductive /n |�d�ktv/ adjective refer-ring to the production of electrical cur-rent in a conductor by a change of mag-netic field � One side effect of lowfrequency in an inductive circuit is thatexcess heat may be produced.inductor

inductor /n|�d�ktə/ noun a compo-nent in the ignition system that pro-duces electrical current in itself by achange of magnetic fieldinert

inert /|�n%�t/ adjective not reactingwith other substanceinert gas

inert gas / |�n%�t $�s/ noun a gas thatdoes not react with other substances �

Inert gases, dust, smoke, salt, volcanicash, oxygen and nitrogen together con-stitute 99% of the atmosphere. (NOTE:The inert gases include helium, neon,argon, krypton and xenon.)inertia

inertia / |�n%�ʃə/ noun the tendency ofa body at rest to stay at rest or of a mov-ing body to continue moving in astraight line unless acted on by an out-side force � Inertia switches operateautomatically when a particular g(acceleration due to Earth’s gravity)loading occurs.inertial

inertial /|�n%�ʃ(ə)l/ adjective referringto inertiainertial navigation system

inertial navigation system /|

�n%�ʃ(ə)l �n�v|�$eʃ(ə)n �sstəm/noun a navigation system which calcu-lates aircraft position by comparingmeasurements of acceleration withstored data, using gyros rather thanradios. Abbreviation INSinferential

inferential /nfə|�renʃ(ə)l/ adjectiveobtained by deduction � The inferentialmethod of ice detection is used in flighttrials for aircraft certification.

inflammableinflammable /n |�fl�məb(ə)l/ adjec-tive easily set on fire � Petrol is aninflammable liquid. (NOTE: Flammableand inflammable mean the samething.) � highly inflammable very eas-ily set on fire, and therefore hazardousinflateinflate /n |�flet/ verb to blow air intosomething and thereby increase its size� A sharp pull on the cord will dis-charge the gas bottle and inflate the lifejacket. Opposite deflateinflationinflation /n|�fleʃ(ə)n/ noun 1. the actof blowing air into something, e.g. aballoon or a tyre, and so increasing itssize � Tyre inflation pressures should bemaintained within 4% limits. 2. a con-tinuing increase in the price of thingsand a decrease in the buying power ofmoney � Annual inflation is 4%. Oppo-site deflationin-flightin-flight /�n flat/ adjective takingplace during a flight � in-flight emer-gency � in-flight oil lossinfluenceinfluence /�nfluəns/ noun a powerwhich affects people or things � TheAtlantic Ocean has a great influence onthe climate of the British Isles. � verb tohave an effect on, to change � In anemergency, a crew member’s power ofcommand will influence the reaction ofpassengers.informinform /n|�fɔ�m/ verb to tell some-body something � After a particularlyheavy landing, the pilot should informan engineer so that checks can be madeto the aircraft structure.informationinformation /�nfə |�meʃ(ə)n/ noun acollection of facts or data � Meteorolog-ical visibility gives information on thetransparency of the atmosphere to a sta-tionary ground observer. (NOTE: Infor-mation has no plural form.)infra-infra- /nfrə/ prefix below or beneathinfraredinfrared /�nfrə |�red/, infra-red adjec-tive referring to the range of invisibleradiation wavelengths from about 750nanometres to 1 millimetre � Solarradiation is short wave and of highintensity while terrestrial radiation isinfra-red.infrequentinfrequent /n |�fri�kwənt/ adjectivenot often � In northern Europe, thun-derstorms are infrequent in winter time.


121 inputingestingest /n|�d"est/ verb to take in, or toabsorb into, something such as a jetengine through the intake � Jet enginesmay be damaged by ingested chunks ofice.ingestioningestion /n|�d"estʃən/ noun the actof taking something into somethingsuch as a jet engine through the intake �Ingestion of birds may seriously dam-age the blades of turbo-fan engines.inherentinherent /n|�hərənt/ adjective exist-ing as a basic or fundamental character-istic � A boiling point of 100°C is aninherent characteristic of water.in hgin hg noun the unit for measuringabsolute pressure. Full form inch(es)of mercuryinhibitinhibit /n |�hbt/ verb to prevent or tolimit the effect of something � Cloudcover inhibits cooling of the Earth’ssurface at night.inhibitioninhibition /�nh|�bʃ(ə)n/ noun theprevention or limitation of the effect ofsomething � Fuel contains chemicalsfor the inhibition of fungal growth.inhibitorinhibitor /n |�hbtə/ noun a device orsubstance which prevents or limits theeffect of something � icing inhibitor asubstance added to fuel to prevent fuelsystem icinginitialinitial /|�nʃ(ə)l/ adjective relating toor occurring at the beginning, the first �initial climb the period of climb imme-diately after take-off � initial letter thefirst letter of a word � initial stage firststage � noun the first letter of a wordinitialsinitials /|�nʃ(ə)lz/ plural noun thefirst letters of a name � His name isJohn Smith, his initials are JS.initiateinitiate /|�nʃiet/ verb to get some-thing going by taking the first step, tostart � In a serious emergency, a mem-ber of the cabin crew may initiate anevacuation of the aircraft.initiationinitiation / |�nʃi |�eʃ(ə)n/ noun the actof getting something going by takingthe first step, starting � Normally speak-ing, the captain is responsible for theinitiation of emergency procedures.initiativeinitiative /|�nʃətv/ noun the poweror ability to begin or to follow throughcompetently with a plan or task � Crew

members must be able to act collec-tively and with initiative in unusual sit-uations.injectinject /n |�d"ekt/ verb to force or drivea fluid into something � An acceleratorpump, operated by the movement of thethrottle lever, injects fuel into the choketube.injectioninjection /n |�d"ekʃən/ noun the forc-ing of fluid into something � Power out-put can be boosted to a value over100% maximum power, by the injectionof a water methanol mixture at the com-pressor inlet or at the combustionchamber inlet.injectorinjector /n|�d"ektə/ noun a devicethat will force or drive a fluid intosomethinginjuryinjury /�nd"əri/ noun damage or harmdone to a person � Escape slides aredesigned to minimise the risk of injuryto passengers when leaving the aircraft.inlandinland /�nlənd/ adjective, adverbreferring to the interior of a country orland mass � Sea fog can extend for con-siderable distances inland.inletinlet /�nlet/ noun 1. an opening whichallows an intake of something � turbineinlet � combustion chamber inlet � Airenters the cabin through an inlet. 2. acoastal feature such as at the mouth of ariverinlet valveinlet valve /�nlət v�lv/ noun thevalve in a piston engine which allowsfuel to enter the cylinderinnerinner /�nə/ adjective positioned far-ther inside � inner wing the part of thewing near the fuselageinner markerinner marker /�nə �mɑ�kə/ noun anILS marker beacon placed between themiddle marker and the end of the ILSrunwayinoperativeinoperative /n |�ɒpərətv/ adjectivenot functioning � To prevent accidentalretraction of the undercarriage, a safetyswitch is fitted in such a way to the oleo,that when it is compressed on theground, the ‘undercarriage up’ selec-tion is inoperative.inputinput /�npυt/ noun something such asenergy, electrical power or information,put into a system to achieve output or aresult � Pumps require high input cur-


INS 122

rent. � If the number of turns on the sec-ondary winding is greater than thenumber of turns on the primary, the out-put voltage from the secondary will begreater than the input voltage to the pri-mary. � pilot control input movementson the flying controls made by the pilotINS

INS abbreviation inertial navigationsysteminsert

insert /n |�s%�t/ verb to put in or into �To prevent tyre explosion due to over-heating, fusible plugs are inserted intothe wheel assemblies. � Insert your tel-ephone number in the space providedon the form. � Insert the key in the lockand turn it.insertion

insertion /n |�s%�ʃ(ə)n/ noun the actof putting in or into � There is a spaceon the form for the insertion of a postaladdress. � When the contours for a par-ticular pressure level have been drawnin, the chart is completed by insertion ofspot temperatures and wind speedinformation.insignificant

insignificant /�ns$ |�nfkənt/adjective not important, of no conse-quence � Minor changes in wind speedor direction are insignificant.inspect

inspect /n |�spekt/ verb to look atsomething closely and to check forproblems or defects � Propellers shouldbe inspected prior to flight.inspection

inspection /n |�spekʃ(ə)n/ noun acareful check for problems � Beforeflight, the pilot should carry out a care-ful inspection of the aircraft.instability

instability /�nstə |�blti/ noun a con-dition in which a body or mass moveseasily, and with increasing speed, awayfrom its original position � Atmosphericinstability often results in strong verti-cal currents of air. � The built-in insta-bility of some modern fighter aircraftmakes them highly manoeuvrable butdifficult to control without fly-by-wiretechnology.install

install /n |�stɔ�l/ verb to put in posi-tion, connect and make ready for use �

Most carburettors are installed in awarm position to help against icing. �installed battery a battery in positionin the aircraft

installationinstallation /�nstə|�leʃ(ə)n/ noun 1.the act of putting equipment or devicesinto position and connecting them foruse � The installation of the computertook three hours. 2. equipment ordevices which are installed � In someauxiliary-power-unit installations theair intake area is protected against iceformation by bleeding a supply of hotair from the compressor over the intakesurfaces.instanceinstance /�nstəns/ noun an examplewhich is used to provide evidence ofsomething � Failure to check fuel levelsbefore take-off is an instance of bad air-manship. � for instance e.g.instantinstant /�nstənt/ adjective immedi-ate, happening immediately � noun avery short period of time � The pilot hasto act in an instant to counteract thesevere downdraughts of a microburst.instinctiveinstinctive /n |�stŋktv/ adjectivenatural, rather than thought-out � Inmost modern light aircraft, use of thetrim wheel is instinctive, i.e. forwardsfor nose down and backwards for noseup.instructinstruct /n |�str�kt/ verb to give infor-mation or knowledge, usually in a for-mal setting such as a lesson or briefing� The safety officer instructs employeeson the use of the breathing equipment. �The training captain instructs traineepilots in the simulator.instructioninstruction /n |�str�kʃən/ noun 1. theact of giving information or knowledge,usually in a formal setting such as a les-son or briefing � Trainees receive first-aid instruction. 2. information on howsomething should be operated or used �You must follow the instructions.instruction manualinstruction manual /n |�str�kʃən�m�njuəl/ noun a book containinginformation on how something shouldbe operated or usedinstructorinstructor /n |�str�ktə/ noun a personwho gives information or knowledge,usually in a formal setting such as a les-son or briefinginstrumentinstrument /�nstrυmənt/ noun adevice for recording, measuring or con-trolling, especially functioning as partof a control system � Airspeed is given


123 intake

on an instrument called the airspeedindicator.instrument approach procedureinstrument approach procedure/�nstrυmənt ə |�prəυtʃ prə |�si�d"ə/noun a set of procedures which a pilotmust follow when approaching an air-port under instrument flight rulesinstrumentationinstrumentation /�nstrυmen |

�teʃ(ə)n/ noun a set of specialisedinstruments on an aircraft � Instrumen-tation in some basic light aircraft isrestricted to a few instruments only. �

Some modern light aircraft have verysophisticated instrumentation.instrument errorinstrument error /�nstrυmənt�erə/ noun the difference between indi-cated instrument value and true valueinstrument flight rulesinstrument flight rules/�nstrυmənt �flat �ru�lz/ plural nounregulations which must be followedwhen weather conditions do not meetthe minima for visual flight � The flightfrom Manchester to Prestwick was con-ducted under instrument flight rules.Abbreviation IFRinstrument flyinginstrument flying /�nstrυmənt�flaŋ/ noun flying using no referencesother than the flight instruments � Someconditions require instrument flying. �

When in cloud, instrument flying isrequired. Abbreviation IFinstrument landinginstrument landing /�nstrυmənt�l�ndŋ/ noun the landing of an aircraftwhen a pilot is relying on informationobtained from instruments rather thanfrom what can be seen outside the air-craftinstrument landing systeminstrument landing system/�nstrυmənt �l�ndŋ �sstəm/ nounaids for an instrument landing approachto an airfield, consisting of a localiser,glide slope, marker beacons andapproach lights � The instrument land-ing system provides both horizontal andvertical guidance to aircraft approach-ing a runway. Abbreviation ILS

COMMENT: The ILS is the most usedprecision approach system in theworld.

instrument meteorological conditionsinstrument meteorological con-ditions /�nstrυmənt �mi�tiərəlɒd"k(ə)l kən |�dʃ(ə)nz/ plural nounmeteorological conditions of visibility

and distance from cloud ceiling whichare less than those for visual meteoro-logical conditions � The basic licencedoes not permit the pilot to fly in instru-ment meteorological conditions. Abbre-viation IMCinstrument ratinginstrument rating /�nstrυmənt�retŋ/ noun an additional qualifica-tion added to a licence, such as PPL,allowing a pilot to fly in instrumentmeteorological conditions � He gainedhis instrument rating in 1992. Abbrevi-ation I/R

COMMENT: An instrument rating isrequired for operating in clouds orwhen the ceiling and visibility are lessthan those required for flight undervisual flight rules (VFR).

insufficientinsufficient /�nsə |�fʃ(ə)nt/ adjec-tive not enough � Insufficient heightresulted in the pilot landing short of therunway.insulateinsulate /�nsjυlet/ verb 1. to preventthe passing of heat, cold or sound intoor out of an area 2. to prevent the pass-ing of electricity to where it is notrequired, especially by using a non-con-ducting material � Bus bars are insu-lated from the main structure and arenormally provided with some form ofprotective covering.insulatinginsulating /�nsjuletŋ/ adjectivepreventing the unwanted passage ofheat, cold, sound or electricityinsulating tapeinsulating tape /�nsjυletŋ �tep/noun special adhesive tape which isused to insulate electrical wires � Insu-lating tape was used to prevent the elec-trical wires from touching.insulationinsulation /�nsjυ |�leʃ(ə)n/ noun anact of or state of preventing the passingof heat, cold, sound or electricity fromone area to another � For continuoussupersonic flight, fuel tank insulation isnecessary to reduce the effect of kineticheating.insulatorinsulator /�nsjυletə/ noun a sub-stance which will insulate, especiallywhich will not conduct electricity �

Wood is a good insulator.intakeintake /�ntek/ noun an openingthrough which a fluid is allowed into acontainer or tube


intake guide vane 124intake guide vaneintake guide vane /�ntek $ad�ven/ noun a device to direct the flowof air at the air-intakeintake lipintake lip /�ntek lp/ noun the rim oredge of the air intake of a jet engine � Assonic speed is approached, the effi-ciency of the intake begins to fallbecause of shock waves at the intake lip.intake temperature gaugeintake temperature gauge/�ntek �temprtʃə �$ed"/ noun aninstrument to indicate the temperatureof air entering an engineintegralintegral /�nt$rəl/ adjective whichcompletes the whole or which belongsto a whole � Meteorology is an integralpart of a flying training course. � inte-gral fuel tanks tanks which are locatedwithin the structure of the aircraftintegrityintegrity /n|�te$rti/ noun the state ofbeing complete and in good workingcondition � The engine fire warningsystem is checked to test its integrity. �

The integrity of an aid used to conductprocedural approaches must be high.intendintend /n|�tend/ verb to have a partic-ular plan, aim or purpose � A battery isintended to supply only limited amountsof power. � intended track desiredcourse of flightintenseintense /n |�tens/ adjective 1. extremein amount � intense heat very high heat� intense wind very strong wind 2. �intense concentration very hard ordeep concentrationintensityintensity /n |�tensti/ noun theamount or strength of heat, light, radia-tion � Surface air temperatures dependmostly on the intensity and duration ofsolar radiation.intentionintention /n |�tenʃən/ noun the courseof action one means or plans to follow �It is not the intention of this chapter togive a detailed description of worldweather. � Our intention is to providesafe, cost-effective flying.inter-inter- /ntə/ prefix betweeninteractinteract /�ntər|��kt/ verb to act oneach other � Angle of attack and theprofile of the wing section interact toproduce lift. � Direct and reflected pathsignals can interact to cause bending ofthe localiser and/or generation of afalse glidepath.

interceptintercept /�ntə |�sept/ verb to stop orinterrupt the intended path of something� When a radio transmission is madefrom a moving platform, there will be ashift in frequency between the transmit-ted and intercepted radio signals.interconnectinterconnect /�ntəkə |�nekt/ verb toconnect together � The fire extinguish-ers for each engine are interconnected,so allowing two extinguishers to beused on either engine.inter-crewinter-crew /�ntə �kru�/ adjective �inter-crew communications commu-nications between members of the crew� The lack of inter-crew communicationcontributed to the accident.interfereinterfere /�ntə |�fə/ verb � to inter-fere with to get in the way of somethingor come between things and thus createa problem � An engine intake close toanother surface, such as the fuselagetail section, must be separated from thatsurface so that the slower boundarylayer air does not interfere with the reg-ular intake flow.interferenceinterference /�ntə|�fərəns/ nounthe prevention of reception of a clearradio signal � Some equipment, such asgenerators and ignition systems, willcause unwanted radio frequency inter-ference. � precipitation interferenceinterference caused by rain, snow orhailinterlockinterlock /�ntə |�lɒk/ noun a series ofswitches and/or relays � Interlocksoperate in a specific sequence to ensuresatisfactory engagement of the autopi-lot. � verb to connect together parts of amechanism, so that the movement oroperation of individual parts affectseach other � The two parts interlock tocreate a solid structure.intermediateintermediate /�ntə|�mi�diət/ adjec-tive 1. in a position between two others2. between beginners and advanced �he is at an intermediate stage in hisstudies he is in the middle of his courseof study � an intermediate level lan-guage student a second languagelearner who has reached a level betweenelementary and advanced levelintermediate approachintermediate approach/�ntəmi�diət ə |�prəυtʃ/ noun the part


125 interrupt

of the approach from arriving at the firstnavigational fix to the beginning of thefinal approachintermediate frequencyintermediate frequency/�ntəmi�diət �fri�kwənsi/ noun thefrequency in a radio receiver to whichthe incoming received signal is trans-formed. Abbreviation IFintermittentintermittent /�ntə |�mt(ə)nt/ adjec-tive stopping and starting at intervals �

The cycle of induction, compression,combustion and exhaust in the pistonengine is intermittent, whereas in thegas turbine, each process is continuous.internalinternal /n|�t%�n(ə)l/ adjective refer-ring to the inside or interior of some-thing � internal damage Oppositeexternalinternal combustion engineinternal combustion engine /n |

�t%�n(ə)l k�m |�b�stʃən �end"n/ nountype of engine in which the fuel is burntwithin the cylinders of the engine, asopposed to the steam engineinternationalinternational /�ntə |�n�ʃ(ə)nəl/adjective between countries � interna-tional call a telephone call betweenpeople in two different countriesInternational Air Transport AssociationInternational Air TransportAssociation /�ntən�ʃ(ə)nəl eə�tr�nspɔ�t ə |�səυsieʃ(ə)n/ noun aninternational organisation that super-vises and coordinates air transport andto which most major airlines belong.Abbreviation IATAInternational Calling FrequencyInternational Calling Frequency/�ntən�ʃ(ə)nəl �kɔ�lŋ �fri�kwənsi/,International Distress Frequency/�ntən�ʃ(ə)nəl ds |�tres �fri�kwənsi/noun 2182 kHz or 500 kHzInternational Civil Aviation OrganizationInternational Civil AviationOrganization /�ntən�ʃ(ə)nəl �svl�evi|�eiʃ(ə)n �ɔ�$ənazeʃ(ə)n/ nounan organisation established in 1947 bygovernments that ‘agreed on particularprinciples and arrangements in orderthat international civil aviation may bedeveloped in a safe and orderly man-ner…’ � Air navigation obstructions inthe United Kingdom are shown onICAO aeronautical charts. Abbrevia-tion ICAO

COMMENT: ICAO is based in Montreal(Canada).

international standard atmosphereinternational standard atmos-phere /�ntən�ʃ(ə)nəl �st�ndəd��tməsfə/ noun an internationallyagreed unit of pressure used in the cali-bration of instruments and the measure-ment of aircraft performance � For enroute weather the datum chosen isinternational standard atmosphere atmean sea level. Abbreviation ISAinterphoneinterphone /�ntəfəυn/ an internaltelephone communications systemwithin an aircraft that enables membersof the crew to speak to one anotherinterpolationinterpolation /n |�t%�pə |�leʃ(ə)n/noun the estimation of a middle valueby reference to known values each side� Spot temperatures at positions otherthan those printed are obtained byinterpolation.interpretinterpret /n |�t%�prt/ verb to under-stand something presented in code orsymbolic form � Aircrew must be ableto interpret information printed on acontour chart.interpretationinterpretation /n |�t%�pr|�teʃ(ə)n/noun an understanding of somethingpresented in code or symbolic form �

Synoptic charts require interpretationin order to understand the informationgiven.interrogateinterrogate /n |�terə$et/ verb totransmit SSR or ATC signals to activatea transponder � Secondary surveillanceradar interrogates the aircraft equip-ment which responds with identificationand height information.interrogationinterrogation /n |�terə|�$eʃ(ə)n/noun the transmission of a SSR or ATCsignal to activate a transponder � Atransponder replies to interrogation bypassing a four-digit code.interrogatorinterrogator /n |�terə$etə/ noun aground-based surveillance radar beacontransmitter/receiver � The questioner,better known as the interrogator, is fit-ted on the ground, while the responder,also known as the transponder, is anairborne installation.interruptinterrupt /�ntə|�r�pt/ verb to breakthe continuity of something � The con-versation was interrupted by a tele-phone call. � In the northern hemi-sphere, the westerly flow of air is


interruption 126

interrupted by variations which occurin pressure patterns.interruptioninterruption /�ntə |�r�pʃən/ noun abreak in the continuity of something �

Because of the summer holiday, therewas an interruption in the flying train-ing course.intersectintersect /�ntə |�sekt/ verb to cutacross each other � Meridians intersectat the poles and cross the equator atright angles.intersectionintersection /�ntə|�sekʃən/ noun thepoint at which two lines cross eachother � The aircraft came to a stop atthe intersection between runways 09and 16. � The intersection of the driftline and the wind vector gives the driftpoint.intertropical convergence zone

intertropical convergence zone/�ntətrɒpk(ə)l kən |�v%�d"əns �zəυn/noun the boundary between the tradewinds and tropical air masses from thenorthern and southern hemispheres �

The intertropical convergence zone isthe zone in which the trade winds fromthe two hemispheres approach eachother. Abbreviation ITCZintervalinterval /�ntəv(ə)l/ noun 1. theamount of space between places orpoints � The intervals at which contoursare drawn depends on the scale of thechart and this interval, known as thevertical interval, is noted on the chart.2. the period of time between twoevents � A precise interval is essentialto obtain correct ignition timing on allcylinders.introduction

introduction /�ntrə|�d�kʃ(ə)n/ noun1. something written which comes atthe beginning of a report, chapter, etc.,or something spoken which comes atthe beginning of a talk � In his introduc-tion, the chief executive praised theefforts of the workforce over the previ-ous 12 months. 2. the act of bringinginto use � The introduction of fly-by-wire technology has made the pilot’stask easier.inverseinverse /n |�v%�s/ adjective reversed inorder or effect � There is an inverserelationship between altitude and tem-perature, i.e. temperature decreases asaltitude increases.

inversioninversion /n |�v%�ʃ(ə)n/ noun 1. anatmospheric phenomenon where coldair is nearer the ground than warm air �Smog is smoke or pollution trapped onthe surface by an inversion of tempera-ture with little or no wind. 2. turningsomething upside down � Inversion ofthe aircraft in flight may result in fuelstoppage.inversion layerinversion layer /n|�v%�ʃ(ə)n �leə/noun a layer of the atmosphere in whichthe temperature increases as altitudeincreasesinvertinvert /n|�v%�t/ verb to turn upsidedown � A glass tube is sealed at oneend, filled with mercury and theninverted so that the open end isimmersed in a bowl containing mer-cury.investigateinvestigate /n |�vest$et/ verb toexamine or look into something in greatdetail � If the starter engaged light stayson after starting, it means that power isstill connected to the starter and, if it isstill on after 30 seconds, the cause mustbe investigated.investigationinvestigation /n |�vest |�$eʃ(ə)n/noun a detailed inquiry or close exami-nation of a matter � accident investiga-tion process of discovering the cause ofaccidents

‘…accident investigation by the FAA andthe German LBA revealed that thecrashed aircraft had been completelyrepainted in an unauthorized paint shop’[Pilot]

investigatorinvestigator /n|�vest$etə/ noun aperson who investigates � Accidentinvestigators found poor coordinationbetween controllers.invisibleinvisible /n |�vzb(ə)l/ adjectiveimpossible to see � Oxygen is an invisi-ble gas.involveinvolve /n |�vɒlv/ verb to include � Inlarge transport aircraft, because of thedistance and numbers of peopleinvolved, effective and rapid communi-cations are required between flightcrew and cabin crew and between cabincrew and passengers. � Two aircraftwere involved in an accident.involvedinvolved /n|�vɒlvd/ adjective over-complex, difficult � The procedure for


127 item

replacing a lost passport is veryinvolved.inward

inward /�nwəd/ adjective directed toor moving towards the inside or interior� To provide protection against smokeand other harmful gases, a flow of100% oxygen is supplied at a positivepressure to avoid any inward leakage ofpoisonous gases at the mask.inwards

inwards /�nwədz/ adverb towardsthe inside or the interior � The dooropens inwards. Opposite outwardsion

ion /�aən/ noun an atom or a group ofatoms that has obtained an electriccharge by gaining or losing one or moreelectrons � negative ion � positive ion �Ultra-violet light from the sun cancause electrons to become separatedfrom their parent atoms of the gases inthe atmosphere, the atoms left withresultant positive charges being knownas ions.ionisation

ionisation /�aəna|�zeʃ(ə)n/, ioni-zation noun the process of producingions by heat or radiation � The intensityof ionisation depends on the strength ofthe ultra-violet radiation and the den-sity of the air.ionosphere

ionosphere /a|�ɒnəsfə/ noun thepart of the atmosphere 50 km above thesurface of the earth � Since the strengthof the sun’s radiation varies with lati-tude, the structure of the ionospherevaries over the surface of the earth.ionospheric

ionospheric /a |�ɒnə |�sferk/ adjec-tive referring to the ionosphereionospheric attenuation

ionospheric attenuation /a |

�ɒnəsferk ə|�tenju |�eiʃ(ə)n/ noun lossof signal strength to the ionosphereionospheric refraction

ionospheric refraction /a |

�ɒnəsferk r|�fr�kʃən/ noun a changein direction as the wave passes throughan ionised layerI/R

I/R abbreviation instrument ratingirregular

irregular / |�re$jυlə/ adjective notregular � Pilots of long-haul flights aresubject to an irregular sleep pattern.irrespective

irrespective /r|�spektv/, irrespec-tive of preposition taking no account of,regardless of � Rescue flights continue

their work irrespective of the weatherconditions.ISA

ISA /�asə/ abbreviation internationalstandard atmosphereisobar

isobar /�asəυbɑ�/ noun a line on aweather chart joining points of equalatmospheric pressure � Isobars areanalogous to contour lines.isobaric

isobaric /asə|�b�rk/ adjective refer-ring to or showing isobars � isobaricchartsisolate

isolate /�asəlet/ verb to separatesomething from other things or some-body from other people � The low-pres-sure fuel cock isolates the airframe fuelsystem from the engine fuel system toenable maintenance and engine remov-als to be carried out.isolated

isolated /�asəletd/ adjective sepa-rate � isolated rain showers wellspaced out rain showersisolation

isolation /�asə |�leʃ(ə)n/ noun thestate of being separated from somethingor somebody � Isolation of the air-craft’s passengers and crew from thereduced atmospheric pressure at alti-tude is achieved by pressurisation of thecabin.isotach

isotach /�asəυ |�t�ʃ/ noun a line ofequal wind speed on charts (NOTE: Windspeed is normally given in the form ofisotachs.)isotherm

isotherm /�asəυθ%�m/ noun a line ofequal temperature on charts � Ascent ofstable air over high ground may resultin a lowering of the 0°C isotherm.issue

issue /�ʃu�/ noun a number or copy �The article was in last month’s issue ofthe magazine. � verb 1. to give out � Thecaptain issued the evacuate command.2. to publish � The magazine is issuedmonthly. 3. to give out, to grant � TheCivil Aviation Authority issue licences.ITCZ

ITCZ abbreviation intertropical conver-gence zoneitem

item /�atəm/ noun a single article orunit in a collection, on a list, etc. �

Before practising stalls, the pilot shouldsecure all loose items in the cockpit.


JJJ symbol jouleJAAJAA abbreviation Joint AviationAuthoritiesjackjack /d"�k/ noun a powered device tomove heavy components, such as con-trol surfaces of large aircraftjacketjacket /�d"�kt/ noun 1. a short coatwith long sleeves worn with trousers orskirt 2. an outer covering or casing �

Liquid cooling of a piston engine isachieved by circulating a liquid aroundthe cylinder barrels, through a passageformed by a jacket on the outside.jamjam /d"�m/ verb to cause movingparts to become locked and unable to bemoved � a jammed door a door whichhas become fixed and unmovable � Theinvestigation revealed that the accidenthad been caused by the controls beingjammed due to a spanner caught in thecontrol cables.JARJAR abbreviation Joint AviationRequirementsjatojato /�d"etəυ/ noun an auxiliary jet orrocket designed to aid the combinedthrust of aircraft jet engines duringtake-offjeopardisejeopardise /�d"epədaz/, jeopardizeverb to put in doubt or danger � Injuryto a crew member will seriously jeop-ardise the successful evacuation of theaircraft.Jeppesen chartJeppesen chart /�d"epəs(ə)n tʃɑ�t/noun a type of aeronautical chart pro-duced by a US company and widelyused in aviationjetjet /d"et/ noun 1. a strong fast streamof fluid forced out of an opening � a jetof water from a pipe 2. a type of engineused to power modern aircraft which

takes in air at the front, mixes it withfuel, burns the mixture and the resultingexpansion of gases provides thrust �

The turbo jet engine was invented byFrank Whittle in 1941. 3. a type of air-craft which has jet engines � The deHavilland Comet was the first commer-cial jet.jetbridge

jetbridge /�d"etbrd"/ noun same asloading bridgejet fighter

jet fighter /�d"et �fatə/ noun afighter plane that is powered by a jetengine or enginesjet lag

jet lag /�d"et l�$/ noun the temporarydisturbance of body rhythms such assleep and eating habits, caused by high-speed travel across several time zones �When I fly to Canada, it always takesme a couple of days to recover from jetlag.jetliner

jetliner /�d"etlanə/ noun a large pas-senger aircraft powered by jet enginesjet plane

jet plane /�d"et plen/ noun an air-craft powered by jet enginesjet-propelled aircraft

jet-propelled aircraft /�d"et prə |

�peld �eəkrɑ�ft/ noun aircraft poweredby jet enginesjet propulsion

jet propulsion /�d"et prə|�p�lʃ(ə)n/noun jet power which provides thrustfor an aircraft � The first known exam-ple of jet propulsion was when Hero, aGreek engineer, made a machine as atoy in the year 120 BC.jet stream

jet stream /d"et stri�m/ noun 1. aband of strong winds at high altitude �

The occurrence of the equatorial jetstream is due to a temperature gradientwith colder air to the south. 2. the flowof gases from a jet engine


129 junction boxjettisonjettison /�d"ets(ə)n/ verb to throwoff or release from a moving aircraft �

The undercarriage failed to retract andthe captain had to jettison the fuel overthe sea before landing the aircraft.joinjoin /d"ɔn/ verb 1. to connect � Jointhe two wires. � With a pencil and ruler,join point A to point B. 2. to bringtogether to make one whole part � Wingpanels are joined by rivets. 3. tobecome a member of a club, etc. � Shehad to pay a membership fee to join thegliding club.jointjoint /d"ɔnt/ noun the place at whichtwo or more things are joined together �Fuselage frame rings are formed withonly one joint. � adjective combined,with two or more things linked togetheror shared by two or more people � ajoint effortJoint Aviation AuthoritiesJoint Aviation Authorities/�d"ɔnt �evi|�eʃ(ə)n ɔ�|�θɒrətiz/ nouna body, consisting of European repre-sentatives, set up to control and regulateaspects of civil aviation in Europe � TheJoint Aviation Authorities is anarrangement between European coun-tries which has developed since the1970s. Abbreviation JAA

COMMENT: The Joint AviationAuthorities currently has 37 member

states, including all the countries of theEuropean Union.

Joint Aviation RequirementJoint Aviation Requirement/�d"ɔnt �evieʃ(ə)n r|�kwaəmənt/noun a JAA requirement concerningdesign, manufacture, maintenance andoperation of aircraft. Abbreviation JAR(NOTE: JARs of relevance to mainte-nance staff are JAR-145, JAR-OPS 1and JAR-OPS 3.)joulejoule /d"u�l/ noun an InternationalSystem unit of electrical, mechanical,and thermal energy � Ignition units aremeasured in joules (1 joule = 1 watt persecond). (NOTE: It is usually written Jwith figures: 25J.)jumbo

jumbo /�d"�mbəυ/ noun same asjumbo jet (informal )jumbo jetjumbo jet /�d"�mbəυ d"et/ noun alarge wide-bodied aircraft capable ofcarrying several hundred passengersjump jet

jump jet /�d"�mp d"et/ noun a jet air-craft with fixed wings that can take offand lands verticallyjunction

junction /�d"�ŋkʃən/ noun a placewhere two things meet � the junction oftwo wiresjunction boxjunction box /�d"�ŋkʃən bɒks/noun electrical unit where a number ofwires can be connected together


KK

K symbol kelvinkatabatickatabatic /k�tə |�b�tk/ adjectivereferring to a cold flow of air travellingdown hillsides or mountainsides � Dueto katabatic effects, cold air flowsdownwards and accumulates over lowground. Compare anabatickatabatic windkatabatic wind /k�tə |�b�tk �wnd/noun a wind which occurs when the airin contact with the slope of a hill iscooled to a temperature lower than thatin the free atmosphere, causing it tosink. Compare anabatic windkelvin

kelvin /�kelvn/ noun the base SI unitof measurement of thermodynamictemperature. Symbol K (NOTE: Temper-atures are shown in kelvin without adegree sign: 20K. Note also that 0°C isequal to 273.15K.)kerosenekerosene /�kerəsi�n/, kerosine nouna thin fuel oil made from petroleum �

Kerosene will only burn efficiently at, orclose to, a ratio of 15:1.KevlarKevlar /�kevlə/ noun a trademark for alight and very strong composite mate-rial � Kevlar and carbon fibre accountfor a large percentage of a modern jetairliner’s structure.keykey /ki�/ noun a piece of metal used toopen a lockkg

kg symbol kilogramkHzkHz symbol kilohertzkick-backkick-back /�kkb�k/ noun the ten-dency of the engine to suddenly reversethe rotation of the propeller momentar-ily when being started � On most mod-ern engines the spark is retarded to top-dead-centre, to ensure easier startingand prevent kick-back.

kilokilo /�ki�ləυ/ noun same as kilogram �This piece of luggage weighs 15 kilos.kilo-kilo- /kləυ/ prefix one thousandkilogramkilogram /�klə$r�m/ noun a meas-ure of weight equal to one thousandgrams � This piece of luggage weighs15 kg. Abbreviation kg (NOTE: It is writ-ten kg after figures.)kilohertzkilohertz /�kləh%�ts/ noun a unit offrequency measurement equal to onethousand Hertz. Abbreviation kHzkilometrekilometre /k|�lɒmtə/ noun a meas-ure of length equal to one thousandmetres (NOTE: It is written km with fig-ures: 150 km. The US spelling is kilom-eter.)kilowattkilowatt /�kləwɒt/ a unit of measure-ment of electricity equal to 1000 watts.Abbreviation kWkilowatt-hourkilowatt-hour /�klə |�wɒt aυə/ nouna unit of 1000 watts of electricity usedfor one hour. Abbreviation kW-hrkinetickinetic /k|�netk, ka|�netk/ adjec-tive referring to motion or somethingproduced by motion � kinetic heatingthe heating of aircraft skin by frictionwith the air as it moves through itkinetic energykinetic energy /ka|�netk �enəd"i/noun energy of motionkitkit /kt/ noun a set of items used for aspecific purpose � A physician’s kitcontaining surgical equipment wouldbe available to a qualified doctorassisting crew with major medicalproblems.knobknob /nɒb/ noun 1. a rounded handle� door knob 2. a rounded control switchor dial � When the control knob ismoved from the central position, the


131 kt

ailerons are moved. 3. a round buttonsuch as on a receiver � Turn the knob toincrease the volume.knotknot /nɒt/ noun a unit of speed equalto one nautical mile per hour, approxi-mately 1.85 kilometres or 1.15 statutemiles per hour. Abbreviation kt (NOTE:Wind speeds in aviation are usuallygiven in knots.)

COMMENT: American light aircraftmanufactured prior to 1976 hadairspeed indicators marked in statute

miles per hour. Knot means ‘nauticalmiles per hour’. It is therefore incorrectto say ‘knots per hour’.

knowledge

knowledge /�nɒld"/ noun familiar-ity, awareness or understanding gainedthrough experience or study � A knowl-edge of the factors which affect surfacetemperatures will contribute a greatdeal to the understanding of meteorol-ogy.kt

kt abbreviation knot


Llabel

label /�leb(ə)l/ noun a small piece ofpaper or cloth attached to an article withdetails of its owner, contents, use, desti-nation, etc. � Hydraulic tubing has alabel with the word HYDRAULIC. �

verb 1. to identify by using a label �

Parts are labelled with the manufac-turer’s name. 2. to add identifyingwords and numbers to a diagram �

There is a standard way of labelling thenavigation vector.lack

lack /l�k/ noun the absence of some-thing or a need for something � Theengine stopped because of a lack of fuel.lag

lag /l�$/ noun a delay, especially thetime interval between an input and theresultant output � There is a time lagbetween the piston moving down andthe mixture flowing into the cylinder. �

jet lagLambert’s projection

Lambert’s projection /�l�mbətsprə |�d"ekʃ(ə)n/ a map projection of theearth based around two standard paral-lels of latitude. � Mercator’s projectionlaminate

laminate /�l�mnət/ noun a sheet ofman-made material made up of bondedlayers � Direction of the fibres andtypes of cloth used in the laminate areall very important factors. � verb/�l�mnet/ to make by using bondedlayers of material � laminated wind-screenslamp

lamp /l�mp/ noun a small light �warning lamp a small light, often red,which informs of a possible danger bylighting up � The switch is connected toa warning lamp on the instrument panelwhich will illuminate if the oil pressurefalls below an acceptable minimum.

landland /l�nd/ noun solid ground, asopposed to the sea � a large land masssuch as Greenland � verb 1. to set anaircraft onto the ground or another sur-face such as ice or water, after a flight �to force land the aircraft to land theaircraft when it can no longer be kept inthe air for any particular reason 2. toarrive on the ground after a flight �

Flight BA321 landed at London Heath-row at 1030 hours. � crash-land. Oppo-site take offlandinglanding /�l�ndŋ/ noun the act of set-ting an aircraft onto the ground oranother surface such as ice or waterafter flight � Take-off and landing arenormally made into wind in order toreduce the length of the take-off andlanding run. � In order to achieve a safelanding in a cross wind, the correcttechniques must be used.landing beaconlanding beacon /�l�ndŋ �bi�kən/noun a radio transmitter at an airfieldthat sends a beam to guide aircraft thatare landinglanding beamlanding beam /�l�ndŋ bi�m/ noun aradio beam from a beacon at a landingfield that helps incoming aircraft tomake a landinglanding chargeslanding charges /�l�ndŋ�tʃɑ�d"z/ plural noun money paid to anairport authority by an operator or pri-vate pilot for landing an aircraftlanding fieldlanding field /�l�ndŋ fi�ld/ noun aplace where aircraft can land and takeofflanding gearlanding gear /�l�ndŋ $ə/ nounsame as undercarriagelanding padlanding pad /�l�ndŋ p�d/ nounsame as helipad


133 latterlanding runlanding run /�l�ndŋ r�n/ noun thedistance on the runway from the touch-down point to the stopping point or tax-iing speedlanding speedlanding speed /�l�ndŋ spi�d/ nounthe lowest speed at which an aircraftmust be flying in order to land safelylanding striplanding strip /�l�ndŋ strp/ noun aspecially prepared area of land for anaircraft to land onlanding weightlanding weight /�l�ndŋ wet/ nounthe weight of an aircraft when it lands,which is made up of its empty weight,the weight of its payload, and theweight of its remaining fuellandmarklandmark /�l�ndmɑ�k/ noun some-thing on the ground which enables thepilot to know where he/she is, e.g. anoticeable building, bridge, coastal fea-ture, etc. � Railway lines are usuallyuseful landmarks.landsidelandside /�l�ndsad/ noun the part ofan airport farthest from the aircraftlanelane /len/ noun same as air lanelapse ratelapse rate /�l�ps ret/ noun the rateat which temperature changes accord-ing to altitude � adiabatic lapse ratethe rate at which air temperaturedecreases as it rises above the Earth’ssurface. As the height increases, thetemperature decreases.

COMMENT: It has been found thatwhen dry or unsaturated air rises, itsrate of fall of temperature with height(i.e. lapse rate) is constant at 3°C per1,000 feet. Similarly, descending airwarms by compression at that rate.This dry adiabatic lapse rate isnormally referred to as the DALR. Airrising and cooling often reaches itsdew point temperature, becomessaturated and any further coolingresults in condensation and therelease of latent heat. Release oflatent heat delays the cooling processand the lapse rate at low levels isreduced to 1.5°C per 1,000 feet. Thistemperature change is called thesaturated adiabatic lapse rate and isnormally referred to as the SALR.

largelylargely /�lɑ�d"li/ adverb mainly,mostly � Heat is transferred from theEarth’s surface upwards largely by con-vection. � The southern hemisphereconsists largely of oceans.

laser ring gyro

laser ring gyro /�lezə rŋ �d"arəυ/noun an instrument that uses beams oflaser light in a closed circuit to detectwhether something is level or notlastlast /lɑ�st/ adjective coming or placedafter all the others � verb 1. to continuefor a period of time � A gust is a suddenincrease in wind speed above the aver-age speed lasting only a few seconds. 2.to stay in good or usable condition � Apiston engine lasts longer if it is han-dled carefully and serviced regularly. �

the last chapter 1. the final chapter ina book 2. the chapter before the onebeing readlatent heat

latent heat /�let(ə)nt �hi�t/ nounheat taken in or given out when a solidchanges into a liquid or vapour, or whena liquid changes into a vapour at a con-stant temperature and pressure � latentheat of fusion the quantity of heatrequired to convert ice, at its meltingpoint, into liquid at the same tempera-ture � latent heat of vaporization thequantity of heat required to convert liq-uid to vapour at the same temperature �latent heat of sublimation the quantityof heat required to convert ice to vapourat the same temperaturelaterallateral /�l�t(ə)rəl/ adjective referringto the side � Drift is the lateral move-ment of the aircraft caused by the wind.lateral axislateral axis /�l�t(ə)rəl ��kss/ nounthe axis of the aircraft from wing tip towing tip about which the aircraftpitches up and down. � axis, pitchlatitude

latitude /�l�ttju�d/ noun the angulardistance north or south of the Earth’sequator, measured in degrees, minutesand seconds, along a meridian, as on amap or chart, etc. � Parallels of latitudeare imaginary circles on the surface ofthe Earth, their planes being parallel tothe plane of the equator. � The centre ofLondon is latitude 51°30’N, longitude0°5’W. Compare longitudelatterlatter /�l�tə/ adjective referring tosomething coming at the end or finish �the latter part of the take-off run thepart of the take-off run immediatelybefore the aircraft leaves the ground �

noun the second of two things men-tioned earlier. Opposite former � of the


launch 134

Airbus A320 and A340, the latter isthe larger aircraft the A340 is thelarger of the twolaunchlaunch /lɔ�ntʃ/ noun a small boatoften used to transport people from alarger boat or ship to the shore � verb 1.to slide or drop a boat into the water tomake it ready for use � While passen-gers are fitting life jackets, crew willopen exits and launch the life-rafts. 2. toforce something into motion � to launcha rocketlavatorylavatory /�l�vətri/ noun same as toi-let 2lawlaw /lɔ�/ noun 1. a basic principledescribing a relationship observed to beunchanging between things while par-ticular conditions are met � the law ofgravity 2. a set of agreed rules � avia-tion lawlayerlayer /�leə/ noun 1. one horizontalpart � The lowest layer of the atmos-phere is called the troposphere. 2. athickness of something � Layers of fluidnext to the surface over which it is flow-ing travels more slowly than layers fur-ther from the surface.layer cloudlayer cloud /�leə klaυd/ noun sameas stratuslayoutlayout /�leaυt/ noun the way in whichthings are arranged � cockpit layout thedesign of the cockpit and the particularplacement of controls, instruments, etc.LCLC abbreviation load controllerLCDLCD /�el si� �di�/ abbreviation liquidcrystal displayLDALDA abbreviation landing distanceavailableLDRLDR abbreviation landing distancerequiredleadlead1 /led/ noun a very heavy softmetallic element. Symbol Pb � lead-free not containing lead � Low-lead orlead-free fuel is used in most modernpiston engines.leadlead2 /li�d/ noun 1. an electrical wireor narrow cable � A lead connects themonitor to the computer. 2. � to takethe lead to take control of a situation �

It is vital in any emergency situationthat a crew member should take thelead. � verb 1. to guide or show the way

by going first � In an emergency situa-tion the aircraft commander may leadhis passengers to safety. � In a smoke-filled cabin, floor lighting leads passen-gers to the emergency exit. 2. to cause �In winter, the cold conditions often leadto frost and fog. � Contraction of metalparts and seals can lead to fluid leak-age. (NOTE: leading – led)lead-acid batterylead-acid battery /�led ��sd�bat(ə)ri/ noun a system of lead platesand dilute sulphuric acid, used as astarter battery or traction batteryleading edgeleading edge /�li�dŋ ed"/ noun thefront part of the wing which meets theoncoming air first � In icing conditions,ice may build up on the leading edges.leakleak /li�k/ noun the escape of liquid orgas from a sealed container, or theamount of liquid or gas that has escaped� Any failure of the aircraft structuremay cause a leak of pressurised airwhich might be very difficult to cure. �exhaust leak an escape of exhaustgases � verb to escape from a sealedcontainer � Fuel may leak from a fueltank if the drain plug is not seated cor-rectly.leakageleakage /�li�kd"/ noun the escape ofliquid or gas from a sealed container �

Any internal or external leakage of fuelwill cause a reduction in the operatingperiod. (NOTE: Leak is normally usedfor an individual instance while leakageis used more generally: There is a fuelleak from the central tank; Fuel leakageis a safety hazard.)leanlean /li�n/ adjective referring to a mix-ture in which the ratio of air to fuel isgreater than usual � Moving the mixturecontrol lever aft to the lean positionreduces the amount of fuel mixing withthe air.lean mixturelean mixture /�li�n �mkstʃə/ noun afuel/air mixture in which the ratio of airto fuel is greater than usualLEDLED /�el i� �di�/ noun a semiconductordiode that emits light when current isapplied. LEDs are used in cockpit dis-plays. Full form light-emitting diodeleelee /li�/ adjective, noun which is pro-tected from the wind � The air on thelee side is drier than that on the wind-


135 level

ward side. � The flow of air over and tothe lee of hills and mountains maycause particularly severe turbulence.Opposite windwardleg

leg /le$/ noun part of a flight patternthat is between two stops, positions, orchanges in direction � An airfield trafficpattern is divided into take-off, cross-wind leg, downwind leg, base leg andfinal approach.

‘…their route was across the States toCanada, Greenland and the North Pole,into Norway, through Europe, back toIceland, then two long legs across theAtlantic via South Greenland and back toSeattle’ [Pilot]

legal

legal /�li�$(ə)l/ adjective lawful orwithin the law � Alcohol concentrationsof 40 milligrams per 100 millilitres, i.e.half the legal driving limit in the UK,are associated with substantialincreases in errors committed by pilots.legend

legend /�led"ənd/ noun a list explain-ing the symbols on a chart or a map � Alegend is usually to be found at the edgeor on the reverse side of most topo-graphical charts.length

length /leŋθ/ noun 1. a measurementalong something’s greatest dimension �the length of the aircraft � The runwaylength is 3 kilometres. 2. a piece ofsomething that is normally measuredalong its greatest dimension � a lengthof pipe 3. the extent from beginning toend � the length of a book 4. extent orduration, the distance between twopoints in space or time � the length of abriefing how much time the briefingtakes � the length of the working lifeof components how long the compo-nents last � the length of a flight 1. thetime it takes to complete a flight � Thelength of the flight meant that there wasno time for a meal to be served to thepassengers. 2. the distance of the flightin nautical miles or kilometres � Thelength of the flight is 100nm.lengthen

lengthen /�leŋθən/ verb to make longor longer � The mercury column short-ens when cooled and, due to expansion,lengthens when heated. Oppositeshorten

lengthwise

lengthwise /�leŋθwaz/ adjective,adverb along the length of something �in a lengthwise directionlengthylengthy /�leŋθi/ adjective 1. long,extensive � He wrote a lengthy report.2. long, which lasts for a long time(NOTE: Lengthy often suggests a meet-ing or explanation which is longer thannecessary and therefore uninteresting.)� lengthy meeting a long meeting �lengthy explanation a long explana-tionlens

lens /lenz/ noun a normally roundpiece of glass with curved surfacesfound in microscopes, telescopes, cam-eras, spectacles, etc.lens-shaped cloudlens-shaped cloud /�lenz ʃept�klaυd/, lenticular cloud /len |�tkjυlə�klaυd/ noun cloud with slightly out-wardly-curved upper and lower sur-faceslessenlessen /�les(ə)n/ verb to make less �

Reverse thrust is used to lessen theloads on brakes and tyres. � Clean fil-ters lessen the possibility of blockage.letdown

letdown /�letdaυn/ noun the descentof an aircraft in preparation for landing,before the actual landing approachlevel

level /�lev(ə)l/ adjective 1. � level withat the same height or position as some-thing else � In most light aircraft, theaeroplane will be in a climb if theengine cowling is level with the horizon.2. having a flat, smooth surface � a levelrunway a runway without bumps, etc.3. on a horizontal plane 4. steady, refer-ring to something with no suddenchanges � speak in a level voice do notraise and lower the sound of your voice� the level tone of an engine theunchanging sound of an engine � levelhead clear thinking � It is essential thatthe crew keeps a level head in an emer-gency. � noun 1. a position along a ver-tical axis � ground level � referencelevel � The tropopause is the level atwhich the lapse rate ceases to be soimportant. � the fluid level in the res-ervoir the point where the surface ofthe fluid reaches up to � high-levelcloud high-altitude cloud 2. a positionon a scale � an advanced level of study3. a relative amount, intensity, or con-


level off 136

centration � an unsafe level of contami-nation � a reduced level of noise � A gasturbine engine has an extremely lowvibration level.level off

level off /�lev(ə)l �ɒf/ verb to start tofly level with the ground after climbingor descending, or make an aircraft dothislever

lever /�li�və/ noun 1. a device with arigid bar balanced on a fixed point andused to transmit force, as in raising aweight at one end by pushing down onthe other � Push the lever fully up toactivate the brake mechanism. � Pushthe button to release the lever. 2. a han-dle used to adjust or operate a mecha-nism � throttle lever � undercarriageselector lever � Feathering is accom-plished by moving the pilot’s controllever. � verb to move as with a lever �

The door would not open so the emer-gency services had to lever it open withspecialised equipment.LF

LF abbreviation low frequencylicence

licence /�las(ə)ns/ noun a documentwhich is proof of official permission todo or to own something

COMMENT: Each licence has its ownspecific requirements and privileges.In the UK, one of the fundamentaldifferences between a Private Pilot’sLicence and other types of licence isthat the holder of a PPL is not allowedto fly for ‘hire or reward’, i.e. the pilotcannot receive payment for flying.

licence holder

licence holder /�las(ə)ns �həυldə/noun 1. a person who has a licence 2. aleather case, etc., in which to keep thelicence documentlicense

license /�las(ə)ns/ noun US same aslicence � verb to give somebody alicence or official permission to do or toown somethinglie

lie /la/ verb 1. to be in a flat position,often horizontal � Seat rails areattached to the floor beams and lie levelwith the flooring. 2. to be situated �

Great circles are represented by curveswhich lie on the polar side of the rhumbline. (NOTE: Care should be taken withthe verbs to lie, as defined here: lie –lay – lain; to lie meaning ‘not to tell thetruth’: lie – lied – lied and lay, meaning

‘to put down’ as in ‘lay the book on thetable’: lay – laid – laid.)life jacketlife jacket /�laf �d"�kt/ noun aninflatable device, sometimes resem-bling a sleeveless jacket, to keep a per-son afloat in water � Pull down the tog-gles to inflate the life jacket.life raftlife raft /�laf rɑ�ft/ noun a small boat-like vessel for use on an emergencyover waterlife vestlife vest /�laf vest/ noun same as lifejacket � You will find a life vest underyour seat.liftlift /lft/ noun 1. a component of thetotal aerodynamic force acting on anaerofoil which causes an aeroplane tofly � In level flight, a lift force equal tothe weight must be produced. � Thepilot can achieve maximum lift by pull-ing hard back on the controls. 2. anelectrically operated machine for mov-ing people or goods between the floorsof a building (NOTE: The US English iselevator.) � verb to move to a higherposition � A foot-pound is the ability tolift a one pound weight a distance ofone foot.

COMMENT: Bernoulli’s principle statesthat if the speed of a fluid increases, itspressure decreases; if its speeddecreases, its pressure increases.Wings are shaped so that the high-speed flow of air that passes over thecurved upper surface results in adecrease in pressure. Lift is createdbecause of the pressure differentialbetween upper and lower surfaces ofthe wing. Lift is also created becausethe angle of attack allows the airflow tostrike the underside of the wing. DanielBernoulli (1700–82) was a Swissscientist.

lightlight /lat/ noun 1. brightness pro-duced by the sun, the moon, a lamp, etc.2. electromagnetic radiation which canbe sensed by the eyes � artificial lightlight made by using electrical, gas, etc.,power 3. a source of light such as a lamp� Switch off the navigation lights. �

adjective 1. without much weight, notheavy � Aluminium is a light metal. 2.of little force or requiring little force � alight wind a gentle wind � light con-trols flying controls which do not needmuch pilot effort to move them 3. of lit-


137 link

tle quantity � light rain � light snow 4.of thin consistency � light oil oil whichpours easilylight aircraftlight aircraft /�lat �eəkrɑ�ft/ noun asmall, single engine aircraft generallyfor private not commercial uselightinglighting /�latŋ/ noun lights or a sys-tem of lights � Cabin lighting isswitched off for take-off and initialclimb. � Emergency floor lightingguides passengers to the emergencyexits.lightninglightning /�latnŋ/ noun a powerfuland sudden electrical discharge from acloud � Lightning is the most visibleindication of thunderstorm activity.lightning activitylightning activity /�latnŋ �k |

�tvti/ noun a period of time whenthere are a lot of lightning flasheslightning strikelightning strike /�latnŋ strak/noun the hitting of something by a dis-charge of lightninglight planelight plane /�lat �plen/ noun USsame as light aircraftlikelylikely /�lakli/ adjective probable �rain is likely rain will probably fall �icing is likely to occur in cumulonim-bus clouds icing is often a problem ifflying in cumulonimbus cloudslimitlimit /�lmt/ noun a point or line pastwhich something should not go � Thereis a time limit of one hour for the exam-ination. � The minimum age limit forholding a PPL in the UK is 17. � theupper limit of cloud the highest pointat which there is cloud � verb to restrictor to prevent from going past a particu-lar point � The amount of cabin bag-gage is limited to one bag per passen-ger.limitationlimitation /�lm|�teʃ(ə)n/ noun theact of limiting or the state of being lim-ited � Limitation of the maximumengine rpm to a little above maximumengine cruise rpm prevents compressorstall at the higher rpm range.lineline /lan/ noun 1. a thin continuousmark as made by a pencil, pen, etc. orprinted � Draw a line from point A topoint B. 2. a real or imaginary markplaced in relation to points of reference� An isobar is a line joining points ofequal pressure. 3. a long row of people,

etc. � a line of people � a line of cumu-lus clouds 4. a row of written or printedwords � Look at line 4 on page 26. 5. atelephone connection to another tele-phone or system � Dial 9 to get an out-side line. 6. an electrical cable or wire �telephone line cable supported onpylons from one telephone exchange toanother � On final approach to an unfa-miliar airfield, pilots of light aircraftshould keep a sharp lookout for powerlines and telephone lines. 7. a system ofpipes � a fuel line 8. a company whichowns and manages a system of trans-portation routes � a shipping line � anairline such as KLM or QANTASlinear

linear /�lniə/ adjective referring to aline, straight � Although air may appearto be still or calm it is, in fact, movingwest to east in space, the linear velocitybeing zero at the poles and approxi-mately 1,000 mph at the equator. � lin-ear scale a horizontal or verticalstraight-line, rather than circular, scaleon an instrumentlinear actuator

linear actuator /�lniə ��ktjuetə/noun an actuator which operates in astraight back and forth manner, e.g. toopen undercarriage doorsline feature

line feature /�lan �fi�tʃə/ noun a use-ful navigational landmark, e.g. a rail-way line, road or riverline of position

line of position /�lan əv pə|

�zʃ(ə)n/ noun same as position lineline of sight

line of sight /�lan əv �sat/ noun aclear path between sending and receiv-ing antennas. Abbreviation LOSline up

line up /�lan ��p/ verb to move air-craft into position ready for departure �

Line up with the nosewheel on the run-way centre line.link

link /lŋk/ noun 1. a connection � Lightaircraft can be steered while taxiing viaa direct link from rudder pedals to nose-wheel. 2. a relationship � There is a linkbetween alcohol abuse and pilot errorresulting in accidents. � verb 1. to makea connection, to join � The connectingrod links the piston to the crankshaft. 2.to establish a relationship between twosituations � They link alcohol abuse andpilot error.


linkage 138linkagelinkage /�lŋkd"/ noun a system orseries of mechanical connections suchas rods, levers, springs, etc. � throttlelinkage � rudder linkage � The linkagefrom the control column to the controlsurfaces should allow full and freemovement.liquidliquid /�lkwd/ adjective having aconsistency like that of water � Liquidoxygen is stored in cylinders. � noun asubstance with a consistency like water� Water is a liquid, ice is a solid.liquid crystal displayliquid crystal display /�lkwd�krst(ə)l ds|�ple/ noun liquid crystalsthat reflect light when a voltage isapplied, used in many watch, calculatorand digital displays. Abbreviation LCDliquid fireliquid fire /�lkwd �faə/ noun oil orpetrol firelistlist /lst/ noun a series of names,words, things to do, etc., arranged oneafter the other in a vertical column �

verb to write a series of names, words,etc. one after the other in a vertical col-umn � List the advantages of a stressed-skin construction.literliter /�li�tə/ noun US same as litrelithiumlithium /�lθiəm/ noun a soft silverymetallic element, the lightest knownmetal, often used in batteries � an alloyof aluminium and lithiumlitmuslitmus /�ltməs/ noun a substancewhich turns red in acid, and blue inalkalilitmus paperlitmus paper /�ltməs �pepə/ nounsmall piece of paper impregnated withlitmus to test for acidity or alkalinitylitrelitre /�li�tə/ noun the volume of one kil-ogram of water at 4°C (= 1,000cc or1.76 pints) (NOTE: It is written l after afigure: 10l; also written liter in US Eng-lish.)livelive /lav/ adjective carrying electricity� live wireliverylivery /�lvəri/ noun the colour schemeand markings on the outside of an air-craft that identify it as belonging to aparticular airlineLMTLMT abbreviation local mean timeloadload /ləυd/ noun 1. the weight or masswhich is supported � The load on theundercarriage decreases as lift

increases and, when the aircraft risesinto the air, the aircraft is supported bythe wings. � load bearing supportingsome weight 2. a force which a struc-ture is subjected to when resistingexternally applied forces � The load onthe control column is increased whenthe aircraft is flown out of trim. 3.something that is carried in the aircraft� fuel load � passenger load thenumber of passengers on board 4. thepower output of a generator or powerplant 5. the resistance of a device or ofa line to which electrical power is pro-vided � verb 1. to put something into acontainer, often for the purpose oftransportation � The aircraft is loadedwith fuel before take-off. 2. to transferdata from disk into a computer mainmemory � She loaded the software ontothe computer.load-bearing structure

load-bearing structure /�ləυd�beərŋ �str�ktʃə/ noun a structurewhich supports the weight of the air-craft in flight or on the groundload controller

load controller /�ləυd kən |�trəυlə/noun a device which monitors the out-put of a generatorload factor

load factor /�ləυd �f�ktə/ noun thestress applied to a structure as a multi-ple of stress applied in 1g flight � Thehigher the angle of bank, the greater theload factor.

COMMENT: In straight and level,unaccelerated flight, the load factor is1. When an aircraft turns or pulls upout of a dive, the load factor increases.An aircraft in a level turn at a bankangle of 60 degrees has a load factorof 2. In such a turn, the aircraft’sstructure must support twice theaircraft’s weight.

loading

loading /�ləυdŋ/ noun 1. the act orprocess of adding a load to an aircraft �loading is in progress passengers, bag-gage, freight, etc., are being put on theaircraft 2. the total aircraft weight ormass divided by wing area � Inertiaswitches operate automatically when aparticular g (acceleration due toEarth’s gravity) loading occurs. 3. aforce or stress acting on an object � cen-trifugal loading centrifugal force act-ing on something � Centrifugal loading


139 logic

moves the valve towards the closedposition. 4. the act of transferring datafrom disk to memory � Loading can bea long process.loading bridge

loading bridge /�ləυdŋ brd"/ nouna covered walkway from an airportdeparture gate that connects to the doorof an aircraft, used by passengers andcrew getting on and off the aircraftload manifest

load manifest /�ləυd �m�nfest/noun a detailed list of the cargo on aflight. Also called load sheetloadmaster

loadmaster /�ləυdmɑ�stə/ noun theperson who is in charge of the work ofloading cargo onto a military or com-mercial transport aircraftload sheet

load sheet /�ləυd ʃi�t/ noun same asload manifestlobe

lobe /ləυb/ noun one of two, four ormore sub-beams that form a directionalradar beam � Any system employingbeam sharpening is vulnerable to sidelobe generation at the transmitter.LOC

LOC abbreviation localiserlocal

local /�ləυk(ə)l/ adjective not broad orwidespread � local meteorologicalconditions weather conditions in therestricted area of a particular placelocal authority

local authority /�ləυk(ə)l ɔ�|�θɒrti/noun a government body responsiblefor the various services of an arealocalised

localised /�ləυkəlazd/, localizedadjective restricted in area or influence� a localized fire a fire which has notspreadlocaliser

localiser /ləυkə |�lazə/, localizernoun a component of the instrumentlanding system that provides horizontalcourse guidance to the runway � If, dur-ing the approach, the aircraft deviatesbeyond the normal ILS glideslopeand/or localiser limits, the flight creware alerted. Abbreviation LOClocality

locality /ləυ |�k�lti/ noun a small geo-graphical area � The highest point in alocality is marked by a dot with the ele-vation marked alongside.local mean time

local mean time /�ləυk(ə)l �mi�n�tam/ noun the time according to themean sun. Abbreviation LMT

local timelocal time /�ləυk(ə)l �tam/ noun thetime in the country you are talkingaboutlocatelocate /ləυ |�ket/ verb 1. to find theposition of � Survival beacons transmita signal which enables search air-craft/vessels to rapidly locate accidentsurvivors still in the sea. 2. to position �The digital flight data recorder islocated in the tail section.locationlocation /ləυ|�keʃ(ə)n/ noun 1. aplace where something can be found �

Before take-off, cabin staff brief passen-gers on the location of emergency exitsand life jackets. 2. finding where some-thing is � Rapid location of survivors isimportant.locatorlocator /ləυ |�ketə/ noun a non-direc-tional beacon used as an aid to finalapproach � Terminal control areasrequire charts which show detail on alarge scale – terminal VORs, locatorbeacons, ILS installations, holding pat-terns, arrival/departure and transitroutes.locklock /lɒk/ noun a device operated by akey for securing a door, etc. � verb 1. tosecure a door by turning a key in thelock � Lock the door before leaving thebuilding. 2. to be in or to move into asecure position 3. to block or preventmoving � Anti-skid braking systemsunits are designed to prevent the brakeslocking the wheels during landing. 4. �to lock on to search for, find and followa target with a thin radar beamlocking pinlocking pin /�lɒkŋ pn/ noun a shortmetal device to prevent a nut from turn-ingloglog /lɒ$/ noun a written record of aflight, flying hours, maintenancechecks, etc., for an aircraft, engine orpropeller � verb to write an entry in alog book or on a log sheet � He calcu-lates headings to steer for each flightstage and logs them.logiclogic /�lɒd"k/ noun electronic circuitswhich obey mathematical laws � Cir-cuit packs consist of basic decision-making elements, referred to as logicgates, each performing operations ontheir inputs and so determining thestate of their outputs.


logical 140logical

logical /�lɒd"k(ə)l/ adjective refer-ring to something which, because ofprevious experience or knowledge, isnatural or expected � Pre-flight checkson light aircraft are made in a logicalmanner from one side of the aircraft tothe other.longeron

longeron /�lɒnd"(ə)rən/ noun themain structural part of an aircraft fuse-lage extending from nose to tail � Long-erons are normally used in aircraftwhich require longitudinal strength forholds underneath the floor.long-haul

long-haul /�lɒŋ �hɔ�l/ adjective trav-elling over a long distance � Crew flyinglong-haul routes have to adapt to timechanges. Opposite short-haullongitude

longitude /�lɒŋ$tju�d/ noun theangular distance on the Earth’s surface,measured east or west from the primemeridian at Greenwich, UK, to themeridian passing through a position,expressed in degrees, minutes, and sec-onds � The centre of London is latitude51°30’N, longitude 0°5’W. Comparelatitudelongitudinal

longitudinal /�lɒŋ$|�tju�dn(ə)l/adjective in a lengthwise directionlongitudinal axis

longitudinal axis/�lɒŋ$tju�dn(ə)l ��kss/ noun theaxis of the aircraft which extends fromthe nose to the tail. � axis, rolllong-range

long-range /�lɒŋ �rend"/ adjective1. covering a long distance � long-range radar 2. � long-range weatherforecast covering a period more than 5days aheadlookout

lookout /�lυkaυt/ noun a carefulwatch � Keep a careful lookout forother aircraft. � to be on the lookoutfor to watch carefully for somethingloop

loop /lu�p/ noun a flight manoeuvre inwhich the aircraft rotates, nose up,through 360° while holding its lateralpositionloop antenna

loop antenna /�lu�p �n |�tenə/ nouncircular-shaped conductive coil whichrotates to give a bearing to a ground sta-tionLORAN

LORAN abbreviation long-range airnavigation system

lose

lose /lu�z/ verb not to have somethingany longer (NOTE: losing – lost) � tolose altitude to descend from higher tolower altitudelossloss /lɒs/ noun no longer havingsomething � The pilot reported loss ofengine power. � loss of control nolonger being able to control � loss oflife death in an accident � loss of a sig-nal disappearance of a signal � Theterm attenuation means the loss ofstrength of a radio signal.loudspeaker

loudspeaker /�laυd |�spi�kə/ noun anelectromagnetic device that convertselectrical signals into audible noise.Also called speakerloungelounge /laυnd"/ noun � VIP lounge aspecial room at an airport for VIPs. �

departure loungelouvrelouvre /�lu�və/ noun thin, horizontalopenings for air cooling � Cold air canbe let into the cabin through adjustablelouvres. (NOTE: The US spelling is lou-ver.)low

low /ləυ/ adjective 1. not high, not tall� a low building � low cloud cloud rel-atively near the surface of the earth �low ground an area of land which is nothigh, as opposed to mountains 2. nothigh, or below normal � an area of lowpressure � low temperature a tempera-ture which shows that it is cold 3. quiet,not loud � noun an area of low atmos-pheric pressure � polar low an area oflow atmospheric pressure over polarregionslower

lower /�laυə/ adjective 1. referring tosomething that is at a low level ortowards the bottom � the lower layers ofthe atmosphere � the lower surface ofthe wing the underneath surface of thewing 2. referring to something which isbelow something else of the same sort �Air is cooler high up than at lower lev-els. Opposite upper � verb 1. to letdown to a lower position � lower theundercarriage move the undercarriageinto position ready for landing � lowerthe flaps set the flaps to a down posi-tion 2. to reduce in amount or intensity� to lower the temperature to reducethe temperature � to lower the pres-sure to decrease the pressure � to lower


141 luggage

the volume (of sound) to make some-thing such as a radio quieter or less loudlower airspace

lower airspace /�ləυə �eəspes/noun the airspace below FL245(approximately 24,500 ft)lower atmosphere

lower atmosphere /�ləυə��tməsfə/ noun the layer of theatmosphere in which changes in theweather take place. Also called tropo-spherelow frequency

low frequency /�ləυ �fri�kwənsi/,low frequency band /�ləυ �fri�kwənsi�b�nd/ noun a radio communicationsrange of frequencies between 30–300kHz. Abbreviation LF

lubricatelubricate /�lu�brket/ verb to oil or togrease moving parts in order to reducefriction � Oil passes through the hollowcrankshaft to lubricate the big-endbearings. � Turbo chargers are lubri-cated by the engine oil system.lubricationlubrication /�lu�br|�keʃ(ə)n/ nounthe act or process of covering movingsurfaces with oil or grease in order toreduce friction � lubrication systemthe tank, pipes, pumps, filters, etc.,which together supply oil to movingparts of the engineluggageluggage /�l�$d"/ noun baggage, i.e.cases and bags that somebody takeswhen travelling


Mmm1 abbreviation metremm2 abbreviation minuteMachMach /m�k/ noun the ratio of thespeed of an object to the speed of soundin the same atmospheric conditions �

Mach 2 equals twice the speed of sound.COMMENT: Named after E. Mach, theAustrian physicist who died in 1916.

machinemachine /mə |�ʃi�n/ noun a devicewith fixed and moving parts that takesmechanical energy and uses it to do use-ful work � A drill is a machine for mak-ing holes in things. � An electrical cir-cuit is designed to carry energy to aparticular device or machine which canthen perform useful work.MachmeterMachmeter /�m�kmi�tə/ noun aninstrument for measuring the Machnumber of an aircraftMach numberMach number /m�k/ noun a numberthat expresses the ratio of the speed ofan object to the speed of soundmagnesiummagnesium /m�$|�ni�ziəm/ noun alight, silvery-white metallic elementthat burns with a brilliant white flame.Symbol Mg (NOTE: The atomic numberof magnesium is 12.)magnesium flaremagnesium flare /m�$ |�ni�ziəmfleə/ noun a device for distress signal-ling at night � to send off magnesiumflaresmagnetmagnet /�m�$nt/ noun an objectthat produces a magnetic field, andattracts iron and steel � Magnetism in amagnet appears to be concentrated attwo points called the poles.magneticmagnetic /m�$ |�netk/ adjectivereferring to or having the power of amagnet or something with a magnetic

field � A freely suspended magnet – notinfluenced by outside forces – will alignitself with the Earth’s magnetic lines offorce which run from the north mag-netic pole to the south magnetic pole.magnetic bearingmagnetic bearing /m�$ |�netk�beərŋ/ noun the angle measured in aclockwise direction of a distant point,relative to magnetic northmagnetic declinationmagnetic declination /m�$ |�netk�dekl |�neʃ(ə)n/ noun same as mag-netic variation � To convert magneticbearing into true bearing it is necessaryto apply magnetic variation at the pointat which the bearing was taken.magnetic fieldmagnetic field /m�$ |�netk �fi�ld/noun area of magnetic influencemagnetic northmagnetic north /m�$ |�netk �nɔ�θ/noun the direction of the Earth’s mag-netic pole, to which the north-seekingpole of a magnetic needle points if unaf-fected by nearby influencesmagnetic polemagnetic pole /m�$ |�netk �pəυl/noun one of the two poles which are thecentres of the Earth’s magnetic fieldmagnetic variationmagnetic variation /m�$ |�netk�veər|�eʃ(ə)n/ noun differences in theEarth’s magnetic field in time and place� To convert magnetic bearing into truebearing it is necessary to apply mag-netic variation at the point at which thebearing was taken. Also called mag-netic declinationmagnetisemagnetise /�m�$nətaz/, magnet-ize verb to convert an object or materialinto a magnet � Ferro-magnetic materi-als are easily magnetised.magnetismmagnetism /�m�$nətz(ə)m/ nouna force exerted by a magnetic field � Anelectric current produces magnetism,


143 maneuver

and movement of a magnet can produceelectricity.magneto

magneto /m�$ |�ni�təυ/ noun a devicethat produces electrical current for dis-tribution to the spark plugs of pistonaero-engines

COMMENT: The crankshaft turns themagnetos, which provide the electricalenergy to create a spark from thespark plugs. This ensures that thespark plugs work even if the aircraft’sbattery and electrical system fail. Mostaircraft have two magnetos per enginein case one fails.

magnify

magnify /�m�$nfa/ verb 1. toincrease the size of, especially by usinga lens, microscope, etc. � It was onlyafter the image was magnified that itwas possible to see the flaw. 2. toincrease the effect of something � Thestress level is magnified at times of highwork load, for example, preparation forlanding. (NOTE: magnifying – magni-fied)magnitude

magnitude /�m�$ntju�d/ noungreatness in size or extent � The magni-tude of the pressure gradient force isinversely proportional to the distanceapart of the isobars. � When the surfacewind speed reaches a particular magni-tude the term gale is used.maiden flight

maiden flight /�med(ə)n �flat/noun the first flight of a new aircraft �

The maiden flight of the A340 was inOctober 1991.main

main /men/ adjective most important;principal � main disadvantages princi-pal negative pointsmain gear

main gear /�men �$ə/ noun twomain landing wheel assembliesmainplane

mainplane /�menplen/ noun an air-craft wing, compared with the tailplane� The region between the mainplanefront and rear spars is commonly sealedoff and used as tanks.maintain

maintain /men |�ten/ verb 1. to keepup, to carry on or continue � to main-tain the present heading to continueon the same heading � to maintain aconstant selected engine speed not tochange the engine speed 2. to keep ingood mechanical or working order �

Aero-engines must be maintained regu-larly to maximise engine life.maintenance

maintenance /�mentənəns/ noun aregular periodic inspection, overhaul,repair and replacement of parts of anaircraft and/or engine � The gas turbineis a very simple engine with few movingparts when compared with a pistonengine, giving it a high reliability factorwith less maintenance. � maintenancemanual the manufacturer’s instructionbook of maintenance procedures

‘…poor maintenance training isexpensive for the airline who notices theproblem in late departures, longer thannecessary maintenance periods and worstof all, crashes’ [Civil Aviation Training]

maintenance crew

maintenance crew /�mentənəns�kru�/ noun ground staff whose respon-sibility it is to keep the aircraft service-able � The maintenance crew workedthrough the night to complete the work.major

major /�med"ə/ adjective important �There are two major cloud groups, stra-tus and cumulus. Opposite minor �major airport a large, important orinternational airport � major problema serious problem. Opposite minormajority

majority /mə|�d"ɒrti/ noun thegreater number or larger part – anythingmore than 50% � The majority of pas-sengers prefer to sit in a non-smokingarea of the cabin.malfunction

malfunction /m�l|�f�ŋkʃən/ noun afailure to work or to function correctly� The oil pressure and temperature ofthe CSDU can be monitored by the pilotand if a malfunction occurs, the pilotcan then choose to disconnect theCSDU from the engine. � verb to func-tion incorrectly or fail to function �

Oscillating outputs from the alternatorscould cause sensitive equipment to mal-function.mandatory

mandatory /�m�ndət(ə)ri/ adjectivecompulsory, required or ordered by anofficial organisation or authority � Firedetection systems in toilets are manda-tory.maneuver

maneuver /mə |�nu�və/ noun US sameas manoeuvre


maneuverability 144maneuverabilitymaneuverability /mə |�nu�v(ə)rə |

�blti/ noun US same as manoeuvra-bilitymaneuvering areamaneuvering area /mə |�nu�v(ə)rŋ�eəriə/ noun US same as manoeuvringareamanifoldmanifold /�m�nfəυld/ noun a sys-tem of pipes for a fluid from singleinput to multiple output or multipleinput to single output � inlet andexhaust manifolds of a piston enginemanifold pressuremanifold pressure /�m�n|�fəυld�preʃə/ noun absolute pressure in theinduction system of a piston enginemeasured in inches of mercurymannermanner /�m�nə/ noun a way of doingsomething � Wind is said to be veeringwhen it changes direction in a clockwisemanner. � Pre-flight checks should bedone in the correct manner.manoeuvrabilitymanoeuvrability /mə |�nu�v(ə)rə |

�blti/ noun the ability and speed withwhich an aircraft can turn away from itsprevious path � Light training aircraftdo not have great manoeuvrability butthey are stable and therefore easier tofly. (NOTE: The US spelling is maneu-verability.)manoeuvremanoeuvre /mə |�nu�və/ noun anydeliberate or intended departure fromthe existing flight or ground path (NOTE:It is also written maneuver in US Eng-lish.) � flight manoeuvre turns, loops,climbs and descents � ground manoeu-vre taxiing and turning onto runwaysand taxiways, etc.manoeuvring areamanoeuvring area /mə |�nu�v(ə)rŋ�eəriə/ noun the part of the aerodromeused for the take-off, landing and taxi-ing of aircraftmanualmanual /�m�njuəl/ adjective refer-ring to the hands, or done or worked byhand � The electronic flight instrumentsystem has two self-test facilities –automatic and manual. � noun a refer-ence book giving instructions on how tooperate equipment, machinery, etc. �

maintenance manual � aircraft operat-ing manualmanual controlmanual control /�m�njuəl kən |

�trəυl/ noun hand-flying an aircraftequipped with an autopilot or automaticflight control system

manually

manually /�m�njuəli/ adverb byhand � The system is switched on man-ually.manufacture

manufacture /�m�njυ |�f�ktʃə/ verbto make a product for sale using indus-trial machines � The centrifugal com-pressor is usually more robust than theaxial flow type and also easier todevelop and manufacture.map

map /m�p/ noun a representation ofthe Earth’s surface on a flat surface suchas a sheet of paper � a map of Africa �

verb to make measurements and calcu-lations of part of the Earth’s surface inorder to produce a mapMAP

MAP abbreviation missed approachpointmargin

margin /�mɑ�d"n/ noun 1. a blankspace bordering the written or printedarea on a page � Write notes in the mar-gin of the book. 2. an amount allowed inaddition to what is needed � safety mar-gin � In some configurations, it is possi-ble for the buffet speed to be less thanthe required 7% margin ahead of thestall.maritime

maritime /�m�rtam/ adjectivereferring to the sea � maritime wind awind blowing from the sea � The RockyMountains of North America act as abarrier to the cool maritime winds fromthe Pacific Ocean.mark

mark /mɑ�k/ noun 1. a visible trace ona surface, e.g. a dot or a line � There aremarks on tyres and wheel rims whichare aligned and indicate the extent oftyre creep. 2. the number of points or apercentage given for academic work �

verb 1. to make a visible line, dot, etc.,on a surface � Mark the departure pointon the chart. 2. to show or indicate �

The weather front marks the boundarybetween the two air masses. 3. to cor-rect or check academic work done by astudent � The instructor marked theexam papers.marked

marked /mɑ�kt/ adjective verynoticeable, clear and definite � amarked increase a noticeable, there-fore possibly large, increase � amarked change in the weather a sig-nificant change in the weather


145 mattermarkermarker /�mɑ�kə/ noun 1. somethingwhich acts as an indicator of somethingsuch as distance or position 2. a radiobeacon that is part of the ILS

COMMENT: The outer marker (OM) isindicated on the instrument panel, by ablue light. The middle marker (MM) isindicated by an amber light and theinner marker (IM) by a white light.

marker dyemarker dye /�mɑ�kə da/ noun abrightly coloured substance used bypeople adrift at sea to draw the attentionof flight crews to their positionmarshalmarshal /�mɑ�ʃ(ə)l/ verb to direct air-craft into their parking positions on theapron by means of hand signals � Aftertaxiing, a marshaller marshals the air-craft to the disembarkation and unload-ing point.marshallermarshaller /�mɑ�ʃ(ə)lə/ noun amember of ground staff whose job is todirect aircraft into parking positions bymeans of hand signals

‘…when under a marshaller’s control,reduce speed to a walking pace’ [CivilAviation Authority, General AviationSafety Sense Leaflet]

marshalling signalsmarshalling signals /�mɑ�ʃlŋ�s$nəlz/ plural noun hand signals usedby a marshaller � Marshalling signalsare used to direct aircraft on theground.MASMAS abbreviation middle airspaceservicemaskmask /mɑ�sk/ noun a device to coverthe face � oxygen mask a device tocover the nose and mouth which is con-nected to an oxygen supply � Anoxia athigh altitudes can be overcome bybreathing through an oxygen mask. �

verb to hide or cover up � When practis-ing instrument flying, the aircraft win-dows are masked to prevent the (stu-dent) pilot from seeing out of theaircraft.MASPSMASPS abbreviation minimum air-craft system performance specificationsmassmass /m�s/ noun 1. the physical vol-ume of a solid body � Mass is a basicproperty of matter and is called weightwhen it is in a field of gravity such asthat of the Earth. 2. a large body ofsomething with no particular shape � a

land mass such as the continent ofAfrica � adjective involving a largenumber of people or things � mass exitthe departure of everybody, or nearlyeverybody, from a placemass ascentmass ascent /�m�s ə |�sent/ noun aslow ascent of a large body of air inregions of low pressure and of warm airrising over a cold air massmastmast /mɑ�st/ noun 1. a vertical polefor a flag or antenna � Ice accretes onthe leading edge of the detector mast. 2.a tube projecting from the underside ofthe aircraft from which liquid can drainwell away from the airframemastermaster /�mɑ�stə/ adjective main orprincipal � master cylinder a hydrauliccylinder from which pressure is trans-mitted to smaller slave cylinders � verbto overcome the difficulty of something� It takes practice to master crosswindlandings in light aircraft.master keymaster key /�mɑ�stə ki�/ noun a keywhich can open a number of doors, etc.master switchmaster switch /�mɑ�stə swtʃ/noun the most important of a number ofswitches operating a systemmatchmatch /m�tʃ/ verb 1. to go welltogether � The most important factorwhen matching a propeller to an engineis tip velocity. 2. to be equal to � Thepolarisation of the antenna must matchthat of the transmitter.materialmaterial /mə |�təriəl/ noun a sub-stance out of which something can bemade � Wood, fabric and paper are allfree-burning materials.MATOMATO abbreviation military air trafficoperationsmatrixmatrix /�metrks/ noun a grid-likearrangement of circuit elements � Oilcoolers consist of a matrix, divided intosections by baffle plates.mattermatter /�m�tə/ noun 1. a physicalsubstance � Mass is a basic property ofmatter. � foreign matter somethingunwanted which is found in a substanceor a device (such as sand or water infuel) � Turbine blades can be damagedby foreign matter such as stones enter-ing through the engine intake on take-off. � solid matter solid substances 2. asubject for discussion, concern or


MATZ 146

action � Safety is a matter of greatimportance. 3. trouble or difficulty �what’s the matter? what’s the prob-lem? � it doesn’t matter it isn’t impor-tant, so don’t worryMATZMATZ abbreviation military aero-drome traffic zonemaximummaximum /�m�ksməm/ adjectivegreatest possible � The maximum dailytemperature is 35°C. � The maximumspeed of the aircraft is 200 kt. � nounthe greatest possible quantity, amount,etc. � There is a net gain of heat by theEarth until terrestrial radiation bal-ances solar radiation when the dailytemperature is at its maximum.maximum total weight authorisedmaximum total weight author-ised /�m�ksməm �təυt(ə)l wet�ɔ�θərazd/ noun the maximum author-ised weight of aircraft fuel, payload,etc., given in the Certificate of Airwor-thiness. Abbreviation MTWAmbmb abbreviation millibarMDAMDA /�em di� �e/ abbreviation mini-mum descent altitudemeanmean /mi�n/ adjective referring tosomething average, midway betweentwo extremes � mean daily tempera-ture average daily temperature � meanwind the average speed of a wind �

noun something having a medium oraverage position, midway between twoextremes � arithmetic mean the aver-age value of a set of numbers � verb 1.to signify or to have something as anexplanation � Airspeed means the speedof the aircraft in relation to the airaround it. 2. to intend to do something� I meant to telephone the reservationsdesk this morning but I forgot. 3. toresult in � Installing a new computernetwork means a lot of problems foreverybody. (NOTE: meaning – meant)mean effective pressuremean effective pressure /�mi�n |

�fektv �preʃə/ noun the average pres-sure exerted on the piston during thepower stroke. Abbreviation MEPmeansmeans /mi�nz/ noun a way of doingsomething which brings a result � Aclear window fitted in the reservoir pro-vides a means of checking hydraulicfluid level during servicing. (NOTE:Means has no plural form.) � by means

of by using � Fuel is transferred fromthe tanks to the carburettor by means ofpipes. � there are various means fornavigation there are various differentmethods used for the purposes of navi-gationmean sea level

mean sea level /�mi�n �si� �lev(ə)l/noun the average level of the sea takingtidal variations into account � BelowFL50 cloud heights are referred to adatum of mean sea level. AbbreviationMSLmean sun

mean sun /�mi�n �s�n/ noun the posi-tion of an imaginary sun in a solar dayof exactly 24 hours, behind the real sunin February and in advance of the realsun in November � Local mean time(LMT) is the time according to the meansun.mean time between failures

mean time between failures/�mi�n tam b |�twi�n �feljəz/ nounfull form of MTBFmean time to repair

mean time to repair /�mi�n �tamtə, tυ/ noun full form of MTTRmeasure

measure /�me"ə/ noun 1. an indica-tion or way of assessing � The way hedealt with the in-flight emergency is ameasure of his skill as a pilot. 2. a refer-ence for discovering the dimensions oramount of something � The litre is ameasure of capacity. 3. a device usedfor measuring � a 1-metre measure aruler that is 1 metre long 4. an actiontaken to get a result � Stricter safetymeasures were introduced. 5. anamount of something � To be a goodpilot, you need a measure of self-confi-dence. � verb 1. to find the dimensionsor amount of something � to measure adistance � to measure an angle � tomeasure the speed of an aircraft � Winddirections are measured from magneticnorth. 2. to be of a particular size,length, quantity, etc. � How much doesthe pipe measure?measurement

measurement /�me"əmənt/ noun 1.an act of measuring � Measurement ofrelative humidity is done using aninstrument called a hygrometer. 2. theresult of measuring � The measure-ments of the room are: height = 4metres, length = 10 metres, width = 4metres.


147 mentalmechanicalmechanical /m |�k�nk(ə)l/ adjec-tive referring to machines � Activationmay be electrical or mechanical. �mechanical pump a pump operated bythe engine rather than by electricalpowermechanical advantagemechanical advantage /m |

�k�nk(ə)l əd |�vɑ�ntd"/ noun the ratioof the output force produced by amachine to the input forcemechanical engineeringmechanical engineering /m |

�k�nk(ə)l �end"|�nərŋ/ noun thestudy of design, construction, and useof machinery or mechanical structures� She gained a degree in mechanicalengineering from university.mechanical linkagemechanical linkage /m |�k�nk(ə)l�lŋkd"/ noun a system of rods, cablesand levers in a light aircraft, which con-nect the control column in the cockpit tothe control surfaces on the wings, tail-plane and finmechanicsmechanics /m|�k�nks/ noun 1. thestudy of the action of forces on matteror material systems 2. the way some-thing works � The mechanics of theföhn wind provide a good illustration ofthe adiabatic process.mechanismmechanism /�mekənz(ə)m/ noun 1.the arrangement of connected parts in amachine or system � the landing gearmechanism � the nose wheel steeringmechanism 2. a physical process � themechanism by which thunderstormsdevelopMEDAMEDA abbreviation military emer-gency division aerodromemedical certificatemedical certificate /�medk(ə)l sə |

�tfkət/ noun a document which con-firms that the named person has beenmedically examined and declared to bein good physical conditionmedical emergencymedical emergency noun a situa-tion when somebody is unwell andquickly needs medical caremediummedium /�mi�diəm/ adjective refer-ring to something that has a position orrepresents a condition midway betweenextremes � high, medium and low fre-quencies � medium level cloud � noun asubstance through which somethingelse is transmitted or carried � Tubesconvey the cooling medium. � The cool-

ing medium for cooling oil can be ram-air or fuel.medium frequencymedium frequency /�mi�diəm�fri�kwənsi/, medium frequencyband /�mi�diəm �fri�kwənsi �b�nd/noun radio frequency range between300 kHz and 3000 kHz – often referredto as medium wave (MW). Abbrevia-tion MFmega-mega- /me$ə/ prefix large. Oppositemicro- (NOTE: The prefix mega- is usedin front of SI units to indicate one mil-lion: megahertz = one million hertz.)megahertzmegahertz /�me$əh%�ts/ noun ameasure of frequency equal to one mil-lion cycles per second. AbbreviationMHzmeltmelt /melt/ verb to become liquid byheating � Ice melts at temperaturesabove freezing. � melting point tem-perature at which a solid turns to liquid� Magnesium has a melting point of1204°F.membermember /�membə/ noun 1. a large,important structural unit � The skin inbonded to the internal members. � Abeam is a member which is designed towithstand loading applied at an angleto it, often perpendicular. 2. a personwho joins a club or organisation � He isa member of the gliding club. 3. a per-son in a team or crew � Most large pas-senger aircraft are now operated by twocrew members.memorisememorise /�meməraz/, memorizeverb to fix in the memory, to learn byheart � It is helpful if a student pilot canmemorise certain items, such as down-wind checks, early in his training.memorymemory /�mem(ə)ri/ noun 1. themental ability of remembering andrecalling past events or information �he has a good memory he remembersthings easily 2. part of a computerwhich is used for the fast recall of infor-mation � The computer cannot runmany programs at the same timebecause it doesn’t have enough mem-ory.mentalmental /�ment(ə)l/ adjective referringto the mind or brain � Anoxia severelylimits physical and mental perform-ance. � mental calculation a calcula-


mention 148

tion done in your head, without usingaids such as pen, paper or calculatormentionmention /�menʃ(ə)n/ verb to refer tosomething briefly � as mentioned inchapter 4 � as I mentioned yesterday �

No one mentioned the incident.MEPMEP abbreviation mean effective pres-sureMercator’s projectionMercator’s projection /m%� |�ketəzprə |�d"ekʃ(ə)n/ noun a map projectionof the Earth onto a cylinder so that allthe parallels of latitude are the samelength as the equator � Since meridianson this projection are represented byparallel straight lines, it is impossibleto represent the poles on Mercator’sprojection. � Lambert’s projection

COMMENT: Named after the Latinisedname of G. Kremer, the Flemish-borngeographer who died in 1594.

mercurymercury /�m%�kjυri/ noun a silver-coloured metallic element, liquid atroom temperature, used in thermome-ters � Manifold pressure gauges arecalibrated in inches of mercury.mercury barometermercury barometer /�m%�kjυri bə |

�rɒmtə/ noun type of barometer wherethe atmospheric pressure is balancedagainst a column of mercury � The prin-ciple of a mercury barometer has notchanged since 1643 when Torricellidemonstrated that the atmosphere cansupport a column of liquid.meridianmeridian /mə |�rdiən/ noun an imagi-nary great circle on the Earth’s surfacepassing through the north and southgeographic polesmeshmesh /meʃ/ noun a net-like structure �verb (of gears) to link together withcogs on another wheelmessagemessage /�mesd"/ noun a shortwritten, coded or verbal communication� The crew can use the public addresssystem to broadcast messages to thepassengers. � There’s a message fromMr. Jones on your desk.metmet /met/ abbreviation meteorologymetalmetal /�met(ə)l/ noun one of themetallic elements e.g. iron, gold, mer-cury, copper, aluminiummetallicmetallic /me |�t�lk/ adjective refer-ring to or like metal � metallic materi-

als metals such as aluminium, titanium,steel, etc. � Some fire extinguishers donot harm metallic, wooden, plastic orfabric materials. � non-metallic mate-rials wood, plastics, fabrics, etc., whichare not made of metalMETARMETAR /�mi�tɑ�/ abbreviation avia-tion routine weather reportmeteorologicalmeteorological /�mi�tiərə |

�lɒd"k(ə)l/ adjective referring to mete-orology � meteorological forecast aprediction of the weather to come �meteorological visibility the greatesthorizontal distance at which objects canbe seen and recognised by an observeron the ground with normal eyesight andunder conditions of normal daylightillumination � Meteorological visibilityis given in metres up to 5,000 metres,and thereafter in kilometres. � MOTNEmeteorological chartmeteorological chart /�mi�tiərə |

�lɒd"k(ə)l tʃɑ�t/ noun a chart of partof the Earth’s surface with informationabout weather conditionsmeteorological conditionsmeteorological conditions/�mi�tiərəlɒd"k(ə)l kən |�dʃ(ə)nz/plural noun a description of the weatherin a given areameteorologistmeteorologist /�mi�tiə |�rɒləd"st/noun a person who studies, reports andforecasts the weather � The analysis ofthe surface chart is the procedure inwhich the meteorologist completes thechart by inserting the fronts and isobarsin their correct positions.meteorologymeteorology /�mi�tiə |�rɒləd"i/ nouna science which studies weather andweather conditions � Terrestrial radia-tion plays an important part in meteor-ology.metermeter /�mi�tə/ noun 1. US same asmetre 2. a device to measure current,rate of flow, vertical distance, speed,etc. � a gas meter � altimeter, amme-ter, flowmetermethanolmethanol /�meθənɒl/ noun a colour-less, toxic, flammable liquid, CH3OH,used as an antifreeze, a general solvent,and a fuel, also called methyl alcohol orwood alcohol � Power output can berestored, or can be boosted to a valueover 100% maximum power, by theinjection of a water/methanol mixture


149 minimum

at the compressor inlet or at the com-bustion chamber inlet.method

method /�meθəd/ noun a particularway of doing something, especially if itis well thought out and systematic � Themost common method of displayingradar information is on a cathode raytube.metre

metre /�mi�tə/ noun an internationalstandard unit of length, approximatelyequivalent to 39.37 inches. Abbrevia-tion m (NOTE: It is also written meter inUS English.)MF

MF abbreviation medium frequencyMFD

MFD abbreviation multi-function dis-playMHz

MHz symbol megahertzmicro-

micro- /makrəυ/ prefix small. Oppo-site mega- (NOTE: The prefix micro- isused in front of SI units to indicate aone millionth part: microsecond = onemillionth of a second.)microburst

microburst /�makrəυb%�st/ noun aparticularly strong wind-shear espe-cially associated with thunderstorms �

The investigation revealed that the crewlost control of the aircraft as it flewthrough the microburst.microlight

microlight /�makrəlat/ noun asmall light aircraft, often with an openfuselage, that can carry one or two peo-ple at low speeds and is used for flyingfor pleasure or reconnaissancemicro-switch

micro-switch /�makrəυswtʃ/ nouna miniature switch used to govern sys-tems automatically � Operation of anaircraft may also be seriously affectedby the freezing of moisture in controls,hinges and micro-switches. (NOTE: Theplural form is micro-switches.)microwave landing system

microwave landing system/�makrəwev �l�ndŋ �sstəm/ nounan extremely accurate guidance systemfor landing aircraft that uses micro-waves. Abbreviation MLSmid-

mid- /md/ prefix middle � mid-sum-mer the middle of the summermid-air

mid-air /�md �eə/ adjective � mid-aircollision collision between aircraft inthe air rather than on the ground

middlemiddle /�md(ə)l/ adjective in the cen-tre � middle marker � noun the centre �the seat in the middle of the rowmiddle airspace servicemiddle airspace service /�md(ə)l�eəspes �s%�vs/ a radar service pro-vided by an air traffic control area radarunit in the airspace between FL100 andFL245. Abbreviation MASmiddle markermiddle marker /�md(ə)l �mɑ�kə/noun an ILS marker beacon onextended runway centre line, usually3500 feet from the runway thresholdMILMIL abbreviation militarymilemile /mal/ noun � statute milemilitarymilitary /�mlt(ə)ri/ adjective relat-ing to war or to the armed servicesmilk runmilk run /�mlk r�n/ noun a routinetrip, especially an airline’s regular flightmillibarmillibar /�mlibɑ�/ noun a unit ofatmospheric pressure equal to 1 thou-sandth of a bar. Symbol mbmilligrammemilligramme /�mli$r�m/ noun onethousandth of a grammemillilitremillilitre /�mlili�tə/ noun one thou-sandth of a litre (NOTE: It is usually writ-ten ml after figures: 35ml. Also writtenmilliliter in US English.)millimetremillimetre /�mlimi�tə/ noun onethousandth of a metre (NOTE: It is usu-ally written mm after figures: 35mm.Also written millimeter in US English.)minmin abbreviation minimumminimaminima /�mnmə/ � minimumminimalminimal /�mnm(ə)l/ adjective verysmall in amount, importance or degree� Safety equipment carried on somelight aircraft may be as minimal as aportable fire extinguisher. � Anyattempt to increase range by applyingpower is of minimal benefit.minimiseminimise /�mnmaz/, minimizeverb to reduce or decrease to the small-est amount possibleminimumminimum /�mnməm/ adjectivesmallest possible � the minimumamount required � Minimum weatherrequirements for a particular operationsuch as runway visual range (RVR). �

noun the smallest or least possiblequantity or amount � Fires should betackled with the minimum of delay. � Tokeep the weight of the fuselage structure


minimum flying speed 150

to a minimum, the difference betweencabin pressures and the external atmos-pheric pressures should be kept to aminimum. (NOTE: The plural form isminima or minimums.)minimum flying speed

minimum flying speed/�mnməm �flaŋ �spi�d/ noun thelowest true air speed at which an air-craft can maintain heightminimum fuel

minimum fuel /�mnməm �fju�əl/noun the amount of fuel required toreach destination and land withoutdelayminimum sector altitude

minimum sector altitude/�mnməm �sektə ��lttju�d/ nounthe lowest altitude at which an aircraftmay fly under emergency conditionsand which will provide a minimumclearance of 1000 ft above all obstacleslocated within a particular sectorminimum separation

minimum separation /�mnməm�sepə |�reʃ(ə)n/ noun the minimum ver-tical or horizontal distance allowedbetween two aircraftminor

minor /�manə/ noun a person underthe age of legal adulthood � adjectivesmall in size or amount and thereforerelatively unimportant. Opposite major� minor repairs repairs which can bemade quickly and with the minimumamount of equipmentminus

minus /�manəs/ preposition reducedby � 6 minus 2 equals 4 (6 – 2 = 4). �

noun a minus sign (-) � minus fortydegrees Celsius (- 40° Celsius)minute

minute noun /�mnt/ 1. a time periodof 60 seconds � There are 60 minutes inone hour. � wait a minute wait a whileor a short period of time 2. a unit ofangular measurement equal to one sixti-eth of a degree � 20 degrees and 20 min-utes east (20° 20’E). � adjective /ma|

�nju�t/ very small indeed � Metalfatigue begins as minute cracks, toosmall to be seen, at the point of maxi-mum stress.miscellaneous

miscellaneous /�msə |�leniəs/adjective various, mixed, not all thesame � The first aid box contains mis-cellaneous items for use in a medicalemergency.

miss

miss /ms/ verb not to get or catch �

Two passengers arrived so late that theymissed the flight.missed approach

missed approach /�mst ə |�prəυtʃ/noun an approach that does not result ina landing and is followed by a go-aroundmissed approach point

missed approach point /�mst ə |

�prəυtʃ �pɔnt/ noun the point at whicha pilot must carry out a missedapproach procedure if a particular vis-ual reference has not been mademissed approach procedure

missed approach procedure/�mst ə|�prəυtʃ prə |�si�d"ə/ noun theaction and flight path to be followedafter a missed approach at a particularaerodromemist

mist /mst/ noun 1. visible watervapour, in the form of very fine drop-lets, in the atmosphere � Mist is thinnerthan fog. 2. liquid in spray form � anair/oil mist � verb � to mist up tobecome covered in tiny water dropletsand therefore prevent clear visionthrough a surface � The windscreenmisted up.mix

mix /mks/ verb to put together inorder to form one mass � It is a fact ofnature that different air masses do notmix together.mixture

mixture /�mkstʃə/ noun somethingwhich is the result of a number of thingsmixed togethermixture control

mixture control /�mkstʃə kən |

�trəυl/ noun a device for controlling theratio of fuel to air entering an engine’scarburettor or fuel injection system.The mixture control is a knob or levermarked in red usually to the right of thethrottle lever. � In order to stop theengine, the mixture control should bemoved fully aft.MLS

MLS abbreviation microwave landingsystemmm

mm abbreviation millimetreMM

MM abbreviation middle markerMMR

MMR /�em em �ɑ�/ abbreviation multi-mode receivermnemonic

mnemonic /n |�mɒnk/ noun some-thing such as a word, sentence or littlepoem which helps the memory


151 molecule

COMMENT: Some of the well knownmnemonics are: ARROW=Airworthiness Certificate, RegistrationDocument, Radio Station Licence,Operating Handbook, Weight andBalance document – documents to becarried in (light) aircraft (U5); BUMFchecks= Brakes, Undercarriage,Mixture, Fuel – downwind checks in alight, single engine aircraft with a fixed-pitch propeller; FREDA= Fuel, Radio,Engine, Direction indicator, Altimeter –airfield approach checks; HASELL=Height, Airframe, Security, Engine,Location, Lookout – pre-stall checks;variation east, magnetic least:variation west, magnetic best= amnemonic to help remember whetherto add or subtract variation.

MOA

MOA abbreviation military operationsareamode

mode /məυd/ noun 1. a particularselected setting for the operation orfunctioning of equipment � automaticmode � manual mode 2. a letter ornumber given to the various pulse spac-ings of airborne transponders andground interrogators � Mode A andmode C for altitude reporting, are usedin air traffic control.model

model /�mɒd(ə)l/ noun a simplifieddescription of a system, often in mathe-matical form, designed to make calcula-tion simpler � The description of theweather patterns is a model only which,in reality, is modified greatly by anumber of factors.moderate

moderate adjective /�mɒd(ə)rət/ 1.referring to something well within lim-its, not extreme � a moderate climate aclimate which is not too hot, not toocold 2. the middle of three descriptionsof intensity or amount, i.e. light, moder-ate, severe � moderate humidityhumidity which is not light or severe �light to moderate varying betweenlight and moderate � light to moderateicing � moderate to severe varyingbetween moderate and severe � moder-ate to severe turbulence � verb/�mɒdəret/ to become or cause tobecome less extreme � The south westwind moderates the climate of the UK �As the wind moderated, the aircraft wasallowed to take off.

modernmodern /�mɒd(ə)n/ adjective up todate, referring to the present day � Mod-ern engines are far more powerful thanengines used in the past.modificationmodification /�mɒdf|�keʃ(ə)n/noun an alteration or change in charac-ter or form which is normally animprovement � There have been manymodifications to the simple carburettorover the years. � As a result of thecrash, modifications were made to therudder linkage.modifymodify /�mɒdfa/ verb to change oralter in order to improve � The landinggear was modified to provide greaterstrength. (NOTE: modifying – modi-fied)modulatemodulate /�mɒdjυ|�let/ verb tochange the frequency, amplitude, phase,or other characteristic of an electromag-netic wave � The ground station trans-mits a code in two short bursts, each ofwhich is modulated with two tones.modulationmodulation /�mɒdju |�leʃ(ə)n/ nouna change in a property of an electromag-netic wave or signal, such as its ampli-tude, frequency, or phase � Pulse mod-ulation is a series of quick, short burstsof energy which are radiated from anantenna which serves both the transmit-ter and the receiver.modulemodule /�mɒdju�l/ noun a replacea-ble detachable unitmoistmoist /mɔst/ adjective a little wet,damp or humid � Warm moist air fromthe Gulf of Mexico can extend into Can-ada.moisturemoisture /�mɔstʃə/ noun water orother liquid � When the air passingthrough the carburettor is reducedbelow 0°C (Celsius), any moisture inthe air changes into ice.moisture contentmoisture content /�mɔstʃə�kɒntent/ noun the amount of water inthe atmosphere or as seen when it con-denses onto cold surfacesmoldmold /məυld/ noun, verb US same asmouldmoleculemolecule /�mɒlkju�l/ noun thesmallest particle into which an elementor a compound can be divided withoutchanging its chemical and physicalproperties � The molecules of a gas


moment 152

move more quickly than the moleculesof a liquid.momentmoment /�məυmənt/ noun 1. a shortperiod of time � It only takes a momentto fill in the log book. 2. a point in time� at the moment at this particular time� He’s not in the office at the moment. 3.the product of a quantity and its perpen-dicular distance from a reference point� A load on the end of a beam creates abending moment. 4. the tendency tocause rotation about a point or an axis �The tailplane provides a pitchingmoment to keep the aircraft level.momentummomentum /məυ|�mentəm/ noun ameasure of the motion of a body equalto the product of its mass and velocity �In rain, the faster an aircraft travels themore water it meets and the greater therelative momentum of the water drop-lets.monitormonitor /�mɒntə/ noun a visual dis-play unit for a computer � verb tocheck, on a continuing basis � Flowme-ters are fitted which allow crew to mon-itor the flow of fuel to each engine.monitor systemmonitor system /�mɒntə �sstəm/noun system for checking and warningmonocoquemonocoque /�mɒnəkɒk/ noun athree-dimensional body with all thestrength in the skin and immediatelyunderlying framework � In monocoqueconstruction there is no internal stiffen-ing, as the thickness of the skin gives thestrength and stability.monoplanemonoplane /�mɒnəυplen/ noun anaircraft that has only one pair of wingsmonsoonmonsoon /mɒn |�su�n/ noun a windfrom the south-west or south that bringsheavy rainfall to southern Asia in thesummer � Although the monsoon windsare thought of as being Asiatic phenom-ena, they do occur over Africa and partsof North America, especially the Gulf ofMexico. � monsoon season a season ofwind and heavy rainfall in tropicalcountriesmorning mistmorning mist /�mɔ�nŋ �mst/ nouna mist which usually disappears beforemidday, as the result of warming fromthe sunMorseMorse /mɔ�s/ noun a code used fortransmitting messages in which letters

of the alphabet and numbers are repre-sented by dots and dashes or short andlong signals � VOR (very high fre-quency omni-directional radio range)stations transmit a 2 or 3-letter auralMorse callsign on the reference signalat least every 30 seconds. (NOTE: Morseis still used for identifying some radiobeacons.)

COMMENT: Named after S. F. B.Morse, the American electrician whodied in 1872.

motion

motion /�məυʃ(ə)n/ noun movement,the act of changing position or place �horizontal motion movement fromside to side � rotary motion circularmovement � vertical motion up anddown movementMOTNE

MOTNE noun a network for theexchange of meteorological informa-tion needed by meteorological offices,VOLMET broadcasting stations, airtraffic service units, operators and otheraeronautical users. Full form Meteoro-logical Operational Telecommunica-tions Network Europemotor

motor /�məυtə/ noun a machinewhich provides power for moving avehicle or device with moving parts �

an electric motor � a hydraulic motor(NOTE: Piston or jet power plants for air-craft are referred to as engines notmotors.)mould

mould /məυld/ noun a hollow shapefor forming plastics, etc. � Moulds areused in the manufacture of plastic com-ponents. � verb to shape, often using amould � Thermo-plastic materialbecome soft when heated and can bemoulded again and again. (NOTE: It isalso written mold in US English.)mount

mount /maυnt/ verb to fix to a support� A propeller consists of a number ofseparate blades mounted in a hub.mountain

mountain /�maυntn/ noun a mass ofrock rising above ground level, higherthan a hill � They flew over mountainsin the south of the country.Mountain Standard Time

Mountain Standard Time/�maυntn �st�ndəd �tam/ noun atime zone of the west-central part of theUSA and Canada, 7 hours behind GMT


153 mutual inductancemountedmounted /�maυntd/ adjective fixedto a support � rear-mounted mountedat the rear of the aircraft � Some aircraftsuch as the Boeing 727 have rear-mounted engines.mountingmounting /�maυntŋ/ noun a sup-porting component or attachment point� Airbus aircraft have engine mount-ings under the wings.movementmovement /�mu�vmənt/ noun achange in place or position � Theupward movement of the piston com-presses the fuel/air mixture. � move-ment of the crankshaft the rotation ofthe crankshaft � the downward move-ment of cool air the downward flow ofcool airmphmph abbreviation miles per hourMSLMSL abbreviation mean sea levelMTAMTA /�em ti� �e/ abbreviation militarytraining areaMTBFMTBF /�em ti� bi� �ef/ noun the aver-age period of time that a piece of equip-ment will operate between problems.Full form mean time between failuresMTTRMTTR /�em ti� ti� �ɑ�/ noun the aver-age period of time required to repair afaulty piece of equipment. Full formmean time to repairMTWAMTWA abbreviation maximum totalweight authorisedmuffmuff /m�f/ noun � acoustic ear muffsmulti-multi- /m�lti/ prefix multiple or manymulti-enginemulti-engine /�m�lti �end"n/,multi-engined /�m�lti �end"nd/adjective � multi-engine(d) aircraftaircraft with more than two enginesmulti-function displaymulti-function display /�m�lti�f�ŋkʃ(ə)n d |�sple/ noun an electroniccockpit instrument which displaysinformation such as weather radar ornavigation data. Abbreviation MFD

multi-mode receivermulti-mode receiver /�m�lti məυdr |�si�və/ noun a type of radio receiverused in navigation and landing that canreceive signals from a variety of differ-ent transmission systemsmultiplanemultiplane /�m�ltiplen/ noun an air-craft with more than one pair of wingsmultiplemultiple /�m�ltp(ə)l/ adjective many� Autoland system redundancy employsmultiple systems operating in such amanner that a single failure within asystem will have little effect on the air-craft’s performance during theapproach and landing operation.multiplicationmultiplication /�m�ltpl|�keʃ(ə)n/noun a mathematical operation to workout a specified number of times thevalue of a number (NOTE: The multipli-cation sign is x.)multiplymultiply /�m�ltpla/ verb to work outa specified number of times the value ofa number � To multiply 20 by 6 is to cal-culate what is 6 times 20 (6 x 20). � 4multiplied by 2 is 8 (4 x 2 = 8). � To cal-culate fuel required, multiply the dura-tion of the flight by the consumption ofthe engine at the required power.multi-purposemulti-purpose /�m�lti �p%�pəs/adjective suitable for many differentuses � multi-purpose tool a tool whichcan be used in many different waysmulti-wheel combinationsmulti-wheel combinations/�m�lti �wi�l �kɒmb|�neʃ(ə)nz/ pluralnoun undercarriages consisting of anumber of wheels on each unitmutualmutual /�mju�tʃuəl/ adjectivedirected and received in equal amountmutual inductancemutual inductance /�mju�tʃuəl n|

�d�ktəns/ noun electro-magnetic fieldin one circuit caused by a quicklychanging magnetic field in another cir-cuit


NN

N abbreviation northnacellenacelle /nə|�sel/ noun a streamlinedhousing for an engine � The ram airintake is located in a wing leading edgeor an engine nacelle fairing.narrownarrow /�n�rəυ/ adjective not wide �

narrow band of cloud � a narrow beamof electrons � The narrow aisles of pas-senger aircraft makes it difficult toevacuate an aircraft quickly. Oppositewide, broadNASNAS abbreviation national airspacesystemNASANASA /�n�sə/ abbreviation NationalAeronautics and Space Administrationnationalnational /�n�ʃ(ə)nəl/ adjectivebelonging to a country � KLM is thenational airline of the Netherlands.National Aeronautics and Space AdministrationNational Aeronautics andSpace Administration /�n�ʃ(ə)nəl�eərənɔ�tks ən �spes əd |

�mnstreʃ(ə)n/ noun a US organisa-tion for flight and space exploration.Abbreviation NASAnational airspace systemnational airspace system/�n�ʃ(ə)nəl �eəspes �sstəm/ noun anintegrated system of control and com-munications facilities that is responsi-ble for ensuring the safe and efficientmovement of aircraft through thenational airspace of the US. Abbrevia-tion NASNational Air Traffic ServicesNational Air Traffic Services/�n�ʃ(ə)nəl eə �tr�fk �s%�vsz/ plu-ral noun the organisation that is respon-sible for air traffic control at most UKairports. Abbreviation NATSNATS

NATS abbreviation National Air Traf-fic Services

naturenature /�netʃə/ noun 1. the world,especially plants, animals and theirenvironment in general � Electricity isone of the fundamental forces of nature.2. sort or type � Action taken by thecrew will depend on the nature of theemergency. 3. the essential qualities ofsomething � the convective nature ofthunderstorms � Magnesium is a firehazard of unpredictable nature.nauticalnautical /�nɔ�tk(ə)l/ adjective refer-ring to the sea � The terms pitch, rolland yaw are nautical in origin.nautical milenautical mile /�nɔ�tk(ə)l mal/noun 1.852 kilometres � One knot isequal to one nautical mile per hour.Abbreviation nm. Compare statutemile (NOTE: A nautical mile is preciselydefined as the length of an arc on theEarth’s surface subtended by an angleof one minute at the centre of theEarth.)NAVAIDNAVAID /�n�ved/ abbreviation navi-gational aidnavigationnavigation /�n�v |�$eʃ(ə)n/ nounthe theory and practice of planning,controlling and recording the directionof an aircraft � The basis of air naviga-tion is the triangle of velocities.navigationalnavigational /�n�v|�$eʃ(ə)nəl/adjective referring to navigation � Theaccuracy of modern navigationalequipment is much greater than oldersystems.navigational aidnavigational aid /�n�v|�$eʃ(ə)nəled/ noun a mechanical or electronicdevice designed to help a pilot navigate� Any type of navigational aid but par-ticularly electronic aids, for exampleADF (automatic direction finding) and


155 never-exceed speed

NDBs (non-directional beacons).Abbreviation NAVAIDnavigational line

navigational line /�n�v|�$eʃ(ə)nəllan/ noun same as position linenavigation lightsnavigation lights /�n�v|�$eʃ(ə)nlats/ plural noun lights on an aircraftconsisting of a red light on the left wingtip, a green light on the right wing tipand a white light on the tail

COMMENT: Navigation lights must beused between sunset and sunrise.

navigation log

navigation log /�n�v |�$eʃ(ə)n lɒ$/noun written details of headings andtimes for a flight � The flight crew routeflight plan is a composite documentwhich also serves as a navigation log.NDBNDB abbreviation non-directional bea-connecessarynecessary /�ness(ə)ri/ adjectiveneeded or essential � A rich mixture isnecessary at slow running. � as neces-sary when needed � Warnings, cautionsand advisory messages are displayedonly when necessary.necessitynecessity /nə |�sesti/ noun some-thing that is necessary or very important� Student pilots should understand thenecessity for treating thunderstormswith great respect.needleneedle /�ni�d(ə)l/ noun a thin metalpointer in an instrument � The needleindicated to zero.needle valve

needle valve /�ni�d(ə)l v�lv/ noun avalve formed of a tapered needle pro-jecting into a small opening in a tube,etc., usually connected to a float, whichprovides fine adjustment of fluid flow �Atmospheric pressure will allow thecapsule to expand, causing the needlevalve to move into the opening thusreducing the flow of fuel.negativenegative /�ne$ətv/ adjective 1. avalue of less than 0 � In a reversing pro-peller, the propeller mechanismincludes a removable ground fine pitchstop which enables the propeller to beset to a negative pitch. 2. referring to anelectric charge of the same sign as thatof an electron � the negative terminalof a battery the terminal of a batterymarked with the symbol – and normallycoloured black rather than red 3. show-

ing refusal � a negative answer no 4.showing resistance or non-co-operation� a negative attitudenegligible

negligible /�ne$ld"b(ə)l/ adjectivesmall or unimportant to the extent that itis not worth considering � Atmosphericattenuation is negligible until the upperend of the UHF (ultra high frequency)band when it increases rapidly. � negli-gible risk almost no riskneoprene

neoprene /�ni�əυpri�n/ noun a typeof synthetic rubbernet

net /net/ adjective after all necessarydeductionsnet dry weight

net dry weight /�net dra �wet/noun the basic weight of an enginewithout fluids and without accessoriesnot essential for the engine to functionnetwork

network /�netw%�k/ noun 1. a com-plex interconnected group or system �

A network of meteorological stationsaround the world exchange informa-tion. 2. a system of lines or channelswhich cross each other � On a map,meridians of longitude and parallels oflatitude form a network of lines called agraticule. 3. a system of computersinterconnected in order to share infor-mationneutral

neutral /�nju�trəl/ adjective, noun 1.indicating an electrical charge which isneither positive nor negative 2. indicat-ing the position of a switch or leverwhich leaves a system active but notengaged, e.g. an engine gear lever posi-tion in which the engine is disconnectedfrom the driven parts 3. indicating themiddle position of a control surfaceproviding no aerodynamic effect otherthan that as part of the wing � After aturn, the auto-control will return theailerons to neutral as the aircraftreturns to straight flight.neutralise

neutralise /�nju�trəlaz/, neutralizeverb to cancel the effect of � Spillagefrom a lead acid battery may be neutral-ised by washing with a diluted solutionof sodium bicarbonate.never-exceed speed

never-exceed speed /�nevər k|

�si�d �spi�d/ noun a speed which mustnot be exceeded. Also called Vne(Velocity Never Exceeded)


night rating 156night ratingnight rating /�nat �retŋ/ noun anadditional qualification gained from acourse of training for night flyingnilnil /nl/ noun nothing, zero � nil driz-zle no drizzlenimbostratusnimbostratus /nmbəυ |�stretəs/noun a cloud forming a low dense greylayer from which rain or drizzle oftenfallsnitrogennitrogen /�natrəd"ən/ noun a col-ourless, odourless gas which makes upfour fifths of the Earth’s atmosphere �

Some aircraft have high pressure air ornitrogen bottles provided in the under-carriage and flap circuits for emer-gency lowering. (NOTE: The atomicnumber of nitrogen is 7.)nmnm abbreviation nautical milenocturnalnocturnal /nɒk|�t%�n(ə)l/ adjectivehappening or appearing during the night� Because there is a requirement for acold ground, a katabatic wind tends tobe nocturnal, but if the slope is snow-covered, it can also occur during theday.no-fly zoneno-fly zone /�nəυ �fla �zəυn/ nounan area over which aircraft, especiallythose of another country, are forbiddento flynominalnominal /�nɒmn(ə)l/ adjective 1. notsignificant or not important � a nomi-nal increase a very small increase 2.named, specific � As an installed bat-tery becomes fully charged by the air-craft generator, the battery voltagenears its nominal level and the chargingcurrent decreases.non-non- /nɒn/ prefix not or nonon-directional beaconnon-directional beacon /�nɒn da|

�rekʃ(ə)nəl �bi�kən/ noun a radio bea-con transmitting a signal by which thepilot can determine his or her bearing.Abbreviation NDBnon-essentialnon-essential /�nɒn |�senʃ(ə)l/adjective not necessary � In order toensure the shortest possible take-offrun, all non-essential equipment wasremoved.non-return valvenon-return valve /�nɒn r|�t%�n�v�lv/ noun a valve which allows afluid to pass in one direction only � Asthe piston moves upwards in the cylin-

der, fluid is drawn in through a non-return valve.non-smoking areanon-smoking area /�nɒn �sməυkŋ�eəriə/ noun an area where smoking isnot allowednormalnormal /�nɔ�m(ə)l/ adjective referringto something which is usual and is to beexpected � under normal conditionswhen everything is as it usually isnormal room temperaturenormal room temperature/�nɔ�m(ə)l �ru�m �temprtʃə/ noun thetemperature regarded as comfortablefor usual daily activitynorthnorth /nɔ�θ/ noun compass point 360°,the direction towards which the mag-netic needle points on a compass � Flytowards the north. � The wind is blow-ing from the north. � north facingmountain side the face of the mountainwhich looks towards the north � adjec-tive 1. referring to areas or regions lyingin the north, referring to the compasspoint 360° � the north coast of France2. the northern part of a region or coun-try � North America � adverb towardsthe north � The aircraft was headingnorth. � compass, magnetic, truenorthboundnorthbound /�nɔ�θbaυnd/ adjectivetravelling towards the north � a north-bound flightnorth-eastnorth-east /�nɔ�θ �i�st/ noun thedirection between north and east � Aftertake-off, the aircraft turned to the north-east. � adjective 1. situated in the north-east � the north-east coast of England 2.blowing from or coming from the north-east � a north-east wind � adverbtowards the north-east � We are headingnorth-east.north-easterlynorth-easterly /�nɔ�θ �i�stəli/ adjec-tive 1. blowing from or coming from thenorth-east � A north-easterly wind wasblowing. 2. moving towards the north-east � Follow a north-easterly direction.north-easternnorth-eastern /�nɔ�θ �i�stən/ adjec-tive referring to or situated in the north-east � the north-eastern part of theUnited Statesnortherlynortherly /�nɔ�ðəli/ adjective 1. situ-ated towards the north � the most north-erly point of a country 2. blowing fromor coming from the north � northerlyairflow airflow coming from the north


157 notice

� a northerly airflow from the polarregions 3. moving towards the north �

We are flying in a northerly direction. �noun a wind which blows from thenorthnorthern

northern /�nɔ�ð(ə)n/ adjective refer-ring to or situated in the north � thenorthern hemispherenorthern hemisphere

northern hemisphere /�nɔ�ð(ə)n�hem |�sfə/ noun the area of the Earthto the north of the equatorNorth Pole

North Pole /�nɔ�θ �pəυl/ noun thepoint which is furthest north on theearth � From the UK the aircraft flewover the North Pole to Vancouver.northward

northward /�nɔ�θwəd/ adjectivegoing towards the north � adverb USsame as northwardsnorthwards

northwards /�nɔ�θwədz/ adverbtowards the north � One of the aircraftwas flying northwards.north-west

north-west /�nɔ�θ �west/ noun thedirection between north and west � Theaircraft turned towards the north-west.� adjective 1. situated in the north-west� the north-west coast of England 2.blowing from or coming from the north-west � a north-west wind � adverbtowards the north-west � We are head-ing north-west.north-westerly

north-westerly /�nɔ�θ �westəli/adjective 1. blowing from or comingfrom the north-west � A north-westerlywind was blowing. 2. moving towardsor to the north-west � Follow a north-westerly direction.north-western

north-western /�nɔ�θ �westən/adjective referring to or situated in thenorth-west � the north-western part ofthe United Statesnorth wind

north wind /nɔ�θ wnd/ noun a windblowing from or coming from the north(NOTE: A wind is named after the direc-tion it comes from.)nose

nose /nəυz/ noun the extreme forwardend of the aircraftnose cone

nose cone /�nəυz kəυn/ noun theforemost part of the nose of a multi-engine aircraft which may house elec-tronic equipment, but not an engine

nose dive

nose dive /�nəυz dav/ noun anextremely steep descent by an aircraftfront firstnose-dive

nose-dive /�nəυz dav/ verb to fallsteeply with the front end pointingdownwardsnose gearnose gear /�nəυz $ə/ noun the nosewheel and supporting struts and link-agesnosewheelnosewheel /�nəυzwi�l/ noun theundercarriage wheel at the front of theaircraft. Compare tailwheelno-smoking sign

no-smoking sign /�nəυ �sməυkŋ�san/ noun a sign, usually lit-up, warn-ing passengers and crew that smoking isnot allowednote

note /nəυt/ noun 1. a brief message ona piece of paper � There’s a note onyour desk. 2. a brief comment made onpaper about something that you arereading, listening to, or watching �

Make notes while you watch the videorecording. 3. a short comment or expla-nation in a text, often at the end of abook or at the bottom of a page 4. apiece of paper money � a £10 note(NOTE: The US English is bill.) 5. amusical tone of definite pitch � The noteof the engine changes as rpm (revolu-tions per minute) is increased. � verb 1.to observe carefully, to take notice �

Note that true north is always along ameridian. 2. to write down � Note thetime of departure on the log sheet. �

Note the time of any incident.‘…immediately you become unsure ofyour position, note the time and, if youare in touch with an ATC unit, especiallya radar unit, you should requestassistance’ [Civil Aviation Authority,General Aviation Safety Sense Leaflet]

noticenotice /�nəυts/ noun 1. a written orspoken announcement 2. a formalwarning or notification � to give noticeto inform an employee or employer inadvance and in writing, of a terminationto a period of employment � As a resultof the accident, the instructor was giventhree months’ notice. � the studentpilot is grounded until further noticethe student pilot cannot fly again untiltold by those in authority that he or shecan continue � verb to observe � While


noticeable 158

doing the pre-flight checks, CaptainSmith noticed that there was a leak ofhydraulic fluid from one of the brakecylinders.noticeable

noticeable /�nəυtsəb(ə)l/ adjectivecatching the attention, easily noticed � anoticeable increase an increase whichis important enough to be observed �

There was a noticeable improvement inthe trainee’s recent exam results.notice board

notice board /�nəυts bɔ�d/ noun ausually wooden board in a corridor orclassroom, etc., where information onpaper can be displayednotification

notification /�nəυtf|�keʃ(ə)n/noun the act of informing somebodyabout something � Notification of thenew procedures will follow in a fewdays. � She received notification thatshe had been accepted for the job.notify

notify /�nəυtfa/ verb to inform � Stu-dents were notified of their exam resultsby post. � The authorities must be noti-fied of all in-flight incidents.nozzle

nozzle /�nɒz(ə)l/ noun a projectingpart with an opening at the end of apipe, for regulating and directing a flowof fluid � The nozzle of a portable fire

extinguisher should be pointed at thebase of the fire.nucleus

nucleus /�nju�kliəs/ noun the centralpart around which other parts aregrouped � An atom consists of a nucleuswith orbiting electrons. � Condensationoccurs on very small particles sus-pended in the air which are known ascondensation nuclei. (NOTE: The pluralform is nuclei.)nullnull /n�l/ noun an instrument readingof zero � the null position the zeroposition � Nulls are used for directionsensing because they are better definedthan the maxima.numerical

numerical /nju� |�merk(ə)l/ adjectivereferring to numbers or digitsnumerical value

numerical value /nju�|�merk(ə)l�v�lju�/ noun a numbernumerous

numerous /�nju�m(ə)rəs/ adjectivevery many, a lot � Large transport air-craft have numerous clearly-markedexits to facilitate rapid evacuation ofpassengers. � Numerous refinements tothe simple actuator will be found in use.nut

nut /n�t/ noun a metal ring whichscrews on a bolt to hold it tight � Turnthe nut anticlockwise to loosen it.


OOATOAT abbreviation 1. operational airtraffic 2. outside air temperatureobeyobey /ə|�be/ verb 1. to carry out orcomply with a command � Pilots mustobey landing instructions. 2. to follow aphysical law � Winds obey Buys Ballot’sLaw.OBIOBI abbreviation omni-bearing indica-torobjectobject /�ɒbd"ekt/ noun 1. somethingthat you can touch and see and that hasa particular form and dimensions � Anygiven object will collect more ice whentravelling at high speed than at lowspeed. 2. intention or aim � The objectof the briefing is to inform all aircrew ofthe new procedures. � verb /əb |�d"ekt/to raise or voice opposition � Staffobjected to the introduction of longerworking hours.oblongoblong /�ɒblɒŋ/ adjective rectangular� an oblong piece of aluminium � nouna rectangleOBSOBS abbreviation omni-bearing selec-torobscureobscure /əb|�skjυə/ adjective notclearly understood � the explanationwas obscure the explanation was diffi-cult to understand because it wasn’tclear � verb to make difficult to see �

Deposits of ice crystals on the wind-screen will obscure vision.obscuredobscured /əb|�skjυəd/ adjective �sky obscured a meteorological term tomean that fog or mist prevents sight ofthe skyobservationobservation /�ɒbzə |�veʃ(ə)n/ nouncareful watching � The type of cloud isestablished by observation and com-parison with cloud photographs.

observe

observe /əb |�z%�v/ verb to watch care-fully � Local wave action can beobserved from a height of 200 feet. �

Wing deflection can be observed fromthe passenger cabin.observerobserver /əb|�z%�və/ noun a personworking in a meteorological stationwho assesses weather conditions by vis-ual means � Meteorological visibility isthe greatest horizontal distance atwhich objects can be seen and recog-nised by an observer on the ground withnormal eyesight and under conditionsof normal daylight illumination.obstacleobstacle /�ɒbstək(ə)l/ noun some-thing which blocks a path or preventsprogress � Low frequency transmissionscan penetrate obstacles such as moun-tains. � Knowing the heights of obsta-cles en route, it must be ensured that inthe event of an emergency, the flightmay be continued in safety.obstacle clearanceobstacle clearance /�ɒbstək(ə)l�klərəns/ noun the fact of being at asufficient height to be able to fly overany obstacles in the areaobstruct

obstruct /əb |�str�kt/ verb to block apath or to prevent the progress of some-thing � Bags and luggage must notobstruct the aisles. � A safety valve isnormally provided, in case the waterseparator assembly becomes obstructedby ice.obstructionobstruction /əb |�str�kʃən/ noun 1.the act or process of obstructing � Theglidepath antenna cannot be placedclose to the centre line of the runwaybecause it would cause an obstruction.2. something which blocks a path orprevents progress � Before start-up, the


obtain 160

air intakes and jet pipes must beinspected, to ensure that they are freefrom any debris or obstruction.

‘…taxiways and aerodrome obstructionsmay be hidden by snow, so ask if you arenot certain’ [Civil Aviation Authority,General Aviation Safety Sense Leaflet]

obtainobtain /əb |�ten/ verb to acquire, to get� Telephone the meteorological office inorder to obtain the latest weather fore-cast. � The probes are positioned in thegas stream in order to obtain an accu-rate temperature reading.obviousobvious /�ɒbviəs/ adjective clear andeasily seen or understood � It is obviousthat high ground will disturb the smoothhorizontal flow of air.occasionoccasion /ə |�ke"(ə)n/ noun the timeat which an event or happening occurs �In recent months the aircraft sufferedtwo engine failures, on the first occa-sion the aircraft force-landed safely. �

The maiden flight of an aircraft is agreat occasion. � on occasions some-timesoccasionaloccasional /ə |�ke"(ə)n(ə)l/ adjec-tive happening from time to time �occasional rain periodic rain � occa-sional turbulence turbulence happen-ing from time to timeoccluded frontoccluded front /ə |�klu�dd fr�nt/noun a weather front created when air isforced upward from the Earth’s surface,as when a cold front overtakes andundercuts a warm front � Jet streamsare very rare near occluded frontsbecause of the much smaller tempera-ture gradient across the fronts.occlusionocclusion /ə|�klu�"(ə)n/ noun theforcing of air upward from the Earth’ssurface, as when a cold front overtakesand undercuts a warm front � If the airahead of the warm front is less coldthan the air behind the cold front, thecold front will undercut the less cold airand form a cold occlusion.occupantoccupant /�ɒkjυpənt/ noun a personwho has a seat in an aircraft � occu-pants the crew plus passengers � In-flight emergency procedures aredesigned to successfully combat air-borne emergencies which threaten thesafety of the aircraft and its occupants.

occupyoccupy /�ɒkjυpa/ verb 1. to have aposition, to be in a place � The passen-ger is occupying the wrong seat. 2. tobusy oneself � Once an evacuationprocess is under way the crew will befully occupied carrying out emergencydrills.occuroccur /ə |�k%�/ verb to happen � Heavyrains occur during the monsoon season.� Tropical revolving storms generallyoccur from June to October. � An acci-dent occurred on June 12th.occurrenceoccurrence /ə |�k�rəns/ noun a hap-pening or event � There were a numberof occurrences of hijacking in the eight-ies. � The occurrence of the equatorialjet stream is due to a temperature gradi-ent with colder air to the south.oceanocean /�əυʃ(ə)n/ noun 1. the body ofsalt water which covers the earth (NOTE:This is a chiefly American usage: Brit-ish English prefers the word sea.) 2.any of the major sea areas of the world� the Atlantic Ocean

COMMENT: The five oceans are: theAtlantic, the Pacific, the Indian, theArctic and the Antarctic (or Southern).

oceanicoceanic /�əυʃi |��nk/ adjective refer-ring to the oceans � The trade windsmaintain their direction over the oce-anic areas, especially the Pacific, morethan over land areas. � an oceaniccrossing a flight across sea or oceanoctaocta /�ɒktə/ noun same as oktaoctane ratingoctane rating /�ɒkten �retŋ/ nounthe ability of the fuel to resist detona-tion, i.e. the higher the number, thegreater is the fuel’s resistance to detona-tionoddodd /ɒd/ adjective 1. strange, peculiar� an odd situation � The fact that moistair is lighter than an equivalent volumeof dry air seems odd to many people. 2.� odd tenth an odd decimal, e.g. 0.1,0.3, etc. � Frequency allocation oflocalisers in the VHF band is 108–112MHz at odd tenths e.g. 108.1 and 109.3,the even decimals being allocated toVOR facilities. 3. indicating a number alittle greater than the approximatenumber given � it is 60-odd miles toour destination it is a little more than60 miles to our destination


161 opaqueodd numberodd number /�ɒd �n�mbə/ noun anumber which cannot be exactlydivided by two, e.g. 1, 3, 5, 7, etc. � A(battery) cell contains an odd numberof plates.OEMOEM /�əυ i� �em/ abbreviation originalequipment manufacturerofferoffer /�ɒfə/ noun something, e.g. a sumof money, that is presented for accept-ance or rejection � He made an offer of$85,000 for the aircraft. � verb 1. toshow readiness to do something � Heoffered to pick up the tickets in advance.2. to present for acceptance or rejection� The company offered her a job andshe accepted it. 3. to provide � The bat-tery offers a short term power capabil-ity.officialofficial /ə |�fʃ(ə)l/ adjective referringto an authority, such as the governmentor a recognised organisation � an offi-cial weather report a weather reportproduced by a meteorological station �

noun a person employed by a govern-ment authority or a corporation � Anofficial of the civil aviation departmentwill be visiting today.offshoreoffshore /�ɒfʃɔ�/ adjective at a dis-tance from the shoreoffshore windoffshore wind /�ɒf |�ʃɔ� wnd/ noun awind which blows from the coasttowards the sea. Compare onshorewindohmohm /əυm/ noun a unit of measure-ment of electrical resistance. � ampere

COMMENT: Ohm’s Law states that thecurrent in a circuit is directlyproportional to the voltage causing itand inversely proportional to theresistance of the circuit.

oiloil /ɔl/ noun a thick mineral liquidused as a fuel or to make mechanicalparts move smoothlyoil panoil pan /�ɔl p�n/ noun US same assumpoktaokta /�ɒktə/, octa noun a unit of visi-ble sky equal to one eighth of total areavisible to the horizon � The amount ofcloud cover is given in oktas.

COMMENT: To measure cloud cover,the sky is divided into imaginarysections, each covering one eighth ofthe total. A cloudless sky is ‘zero

oktas’, and a sky which is completelycovered with clouds is ‘eight oktas’ or‘eight eighths’.

oleooleo /�əυliəυ/ noun a telescopic strutin the undercarriage which absorbsimpact loads on landing � A safetyswitch is fitted in such a way to the oleo,that when the oleo is compressed on theground, the ‘undercarriage up’ selec-tion cannot be operated. Full formoleo-pneumaticOMOM abbreviation outer marketomitomit /əυ |�mt/ verb to leave out, not toinclude � High charts show only infor-mation relevant to high altitude flightsand many beacons/aids which are pro-vided for low operations are omitted tokeep the chart clear. (NOTE: omitting –omitted)omni-bearing indicatoromni-bearing indicator /�ɒmni�beərŋ �ndketə/ noun a cockpitinstrument that displays VOR informa-tion and is used for radio navigation.Abbreviation OBIomni-bearing selectoromni-bearing selector /�ɒmni�beərŋ s|�lektə/ noun a knob on anomni-bearing indicator which thepilot turns to select a radial from a VORstation. Abbreviation OBSomnirangeomnirange /�ɒmnirend"/ noun avery-high-frequency radio navigationnetwork that allows pilots to choose andfly on any bearing relative to a transmit-ter on the groundone-in-sixty ruleone-in-sixty rule /�w�n n �sksti�ru�l/ noun in navigation, every 1° oftrack error, and every 60 nautical milesflown, results in the aircraft being 1 nmoff trackonshoreonshore /�ɒnʃɔ�/ adjective towardsthe coastonshore windonshore wind /�ɒnʃɔ� �wnd/ noun awind which blows from the sea towardsthe coast. Compare offshore windopacityopacity /əυ|�p�sti/ noun the state ofnot allowing light to pass through �

Sometimes, it is possible to estimate thedepth and opacity of the layer of mist orfog from the ground observations.opaqueopaque /əυ|�pek/ adjective not allow-ing light to penetrate or pass through �

Rime ice is an opaque, white, granularice which forms on leading edges.


opening 162opening

opening /�əυp(ə)nŋ/ noun 1. a spacewhich acts as a passage through whichsomething or somebody can go � aninlet valve opening 2. a formal start ofoperation � the opening of the new fly-ing school 3. a vacancy for a job �

There’s an opening for a new chiefground instructor.open-skies

open-skies /�əυpən �skaz/ adjectivereferring to a policy of allowing aircraftbelonging to any country to fly over anarea, without restrictions on surveil-lance of military installationsoperate

operate /�ɒpəret/ verb 1. to controlthe working of � The control columnoperates the ailerons and elevators. �

The flaps are operated by a switch. 2. touse or manage � The airline operates afleet of Boeing aircraft. 3. to perform orfunction � Jet transports operate athigh altitudes. 4. to perform a surgicalprocedure, by cutting into the body �

The surgeon operated on the patient.operating jack

operating jack /�ɒpəretŋ d"�k/noun a device which converts rotarymotion into linear or reciprocatingmotion in order to move heavy controlsurfacesoperating weightoperating weight /�ɒpəretŋ wet/noun the total mass of aircraft ready forflight but excluding fuel and payload �

The type of undercarriage fitted to anaircraft is governed by the operatingweight.operationoperation /�ɒpə |�reʃ(ə)n/ noun 1. theprocess of making something work �

The operation of the ignition system ina light aircraft is quite simple. 2. �long-haul operations flying over long-distance routes 3. an effect � to comeinto operation to come into effect �

The new procedures come into opera-tion on 1st January. 4. a surgical proce-dure � The doctor performed an opera-tion. 5. a procedure such as addition orsubtraction

‘…periodically check the carburettorheating system and controls for propercondition and operation’ [Civil AviationAuthority, General Aviation Safety SenseLeaflet]

operational

operational /�ɒpə |�reʃ(ə)nəl/ adjec-tive 1. working or functioning � Air

traffic control facilities were not opera-tional at the time of the accident. � theoperational life of the aircraft theexpected working life of an aircraft 2.ready for use, referring to an aircraft ina suitable condition to fly � an opera-tional aircraft an aircraft that can beused for its assigned purposeoperational air traffic

operational air traffic/�ɒpəreʃ(ə)nəl �eə �tr�fk/ nounflights operating in accordance withmilitary air traffic service procedures.Abbreviation OAToperations department

operations department /�ɒpə |

�reʃ(ə)nz d|�pɑ�tmənt/ noun the partof an airline or airport organisationwhich deals with flight operationsoperative

operative /�ɒp(ə)rətv/ adjectivefunctioning or working � The system isnow operative after the recent mainte-nance.operator

operator /�ɒpəretə/ noun a personwho operates or uses equipment � Aring graticule around the edge of thecathode ray tube enables the operatorto read the bearing directly.oppose

oppose /ə |�pəυz/ verb 1. to workagainst � In level flight, the force of liftopposes the force of gravity. 2. to reject,be in conflict with or try to prevent �

The local people oppose the building ofthe new runway. 3. � as opposed to incontrast with � over sea as opposed toover landopposite

opposite /�ɒpəzt/ adjective 1. situ-ated or placed directly across fromsomething, facing � opposite sides of abuilding the back and front of a build-ing 2. completely different, the reverse� For every action there is an equal andopposite reaction. � noun somethingcompletely different, the reverse � Theopposite of a katabatic wind is an ana-batic wind. � The opposite of starboardis port. � going in opposite direc-tions 1. moving away from each other2. moving towards each otheropposition

opposition /�ɒpə|�zʃ(ə)n/ noun � inopposition against � Drag acts in oppo-sition to thrust. � The electromotiveforce that is produced by all motors is inopposition to supply voltage and is


163 originate

directly proportional to motor rpm (rev-olutions per minute).optimumoptimum /�ɒptməm/ adjective refer-ring to the point at which the conditionor amount of something is the best �

The optimum altitude for jet aircraft ishigher than that for piston engine air-craft. � noun the point at which the con-dition or amount of something is thebest � Generally speaking, engine out-put is at its optimum at cruising speed.optionoption /�ɒpʃən/ noun a choice oralternative � On a bad approach, thepilot of a powered aircraft always hasthe option of going around. � He wasgiven the option of buying two aircraftinstead of one.orbitorbit /�ɔ�bt/ noun the path of a planet,or of a satellite. as it moves aroundanother celestial body. � A year is thetime taken for the Earth to complete oneorbit round the sun. � to put into orbit,to send into orbit to launch somethinginto space so that it revolves around acelestial body such as the sun � verb torevolve around � The Earth orbits thesun. (NOTE: orbiting – orbited)orderorder /�ɔ�də/ noun 1. an instructiongiven as a command by somebody inauthority � The captain gave the orderto evacuate the aircraft. 2. the sequenceof occurrence � The firing order ofsparking plugs in a piston engine is 1, 3,4, 2. � alphabetical order arrangementin which words beginning with letter Acome first, followed by those beginningwith letter B, then C, etc. � numericalorder arrangement in which the lowestnumbers (1, 2, 3, etc.) come first andhigher numbers (25, 26, 27, etc.) comelater 3. a condition or state � Althoughthe aircraft is old, it is in good workingorder. � out of order not working � Thetelephone is out or order. 4. � in theorder of approximately � VOR (veryhigh frequency omni-directional radiorange) beacons of 200 watts have arange in the order of 200 nm (nauticalmiles). � in order to so as to � Indicatedairspeed must be corrected in order toobtain true airspeed. � verb 1. to give acommand � Before impact, the captainwill order the crew to secure themselvesat their assigned emergency stations. 2.

to put in a sequence � Order the items inimportance from 1 to 10.organisationorganisation /�ɔ�$əna |�zeʃ(ə)n/,organization noun 1. an association ofpeople working together for the samecause � The World MeteorologicalOrganization � The International CivilAviation Organization 2. the act ofputting things into a structured and sys-tematic form � The organisation oftraining materials for the new self-access learning centre is under way. 3.planning � Captain Scott is responsiblefor the organisation of examinations.organiseorganise /�ɔ�$ənaz/, organize verb1. to arrange into a system � Organiseyour notes so that you can find thingseasily. 2. to plan � The trip was wellorganised and everybody enjoyed them-selves.orientateorientate /�ɔ�riəntet/ verb to locatein relation to the compass � The firststep in map reading is to orientate thechart by relating the direction of landfeatures to their representation on thechart.orientationorientation /�ɔ�riən |�teʃ(ə)n/ noun aposition in relation to the compass �

The horizontal situation indicator (HSI)presents a selectable, dynamic colourdisplay of flight progress and plan vieworientation.orificeorifice /�ɒrfs/ noun an opening,mouth or vent � The liquid expands andbuilds up a pressure differential acrossan orifice which leads to the expansionchamber.originorigin /�ɒrd"n/ noun 1. a source, theplace where something starts � An airmass takes on the characteristics of itsplace of origin. 2. the base from whicha map projection is drawn � The valueof convergence used is correct at theparallel of origin.originaloriginal /ə |�rd"ən(ə)l/ adjectivebefore all others, the first � The atmos-phere is said to be stable if, when a par-cel of air is displaced vertically, it tendsto return to its original level.originateoriginate /ə|�rd"net/ verb to be cre-ated or to come into being � Tropicalrevolving storms originate within 5–15°of the equator. � Aircraft fires after an


orographic 164

emergency landing, often originate inthe wing area.orographicorographic /�ɒrə|�$r�fk/ adjectivereferring to mountains � orographicuplift the lifting of air masses in contactwith mountain regionsorographic cloudorographic cloud /�ɒrəυ$r�fk�klaυd/ noun a cloud formed by airbeing forced upward over mountainousareasorthomorphicorthomorphic /�ɔ�θəυ |�mɔ�fk/adjective of the correct shape � Anorthomorphic chart is one which hasmeridians and parallels which intersectat right angles and, at any point on thechart, the scale must be the same in alldirections.orthomorphismorthomorphism /�ɔ�θəυ |

�mɔ�fz(ə)m/ noun a shape representa-tion on a map � Orthomorphism meansthat bearings may be measured cor-rectly at any point on a chart.oscillateoscillate /�ɒslet/ verb 1. to moveregularly between extremes 2. toincrease or decrease regularly so as toproduce oscillations � Instability pro-tection is incorporated to guard againstoscillating outputs from the alternators.oscillationoscillation /�ɒs|�leʃ(ə)n/ noun 1. aregular movement between extremes �

Ridge waves can be thought of as oscil-lations about the stable state of theundisturbed air flow with the range ofhills providing the disturbance. 2. a reg-ular increase and decrease of electricalcurrent � The supply is subject to oscil-lation.oscillatoroscillator /�ɒsletə/ noun an elec-tronic circuit that produces a pulse or asignal at a particular frequency � Thelocal oscillator replicates the radio fre-quency of the frequency generator atthe transmitter.outout /aυt/ adverb � out of away from,no longer inoutboardoutboard /�aυtbɔ�d/ adverb in adirection away from the centre of an air-craft � adjective situated away from themain body of an aircraft and towardsthe wing tipsoutboundoutbound /�aυtbaυnd/ adjective,adverb towards a destination away froma VOR � The aircraft flies outbound

from the beacon along the airway andinbound to the facility at the other endof the leg. � outbound traffic aircraftflying away from an airfieldoutbreakoutbreak /�aυtbrek/ noun a suddenstart � Showers are local outbreaks ofprecipitation from detached cumulus orcumulonimbus. � Hand operated fireextinguishers are provided to combatany outbreaks of fire in the flight crewcompartment and passengers cabins.outerouter /�aυtə/ adjective 1. external �

Pneumatic de-icer boots are made fromvulcanised rubber fabric with an outercovering of neoprene. 2. positionedaway from the centre � Winds near anti-cyclones are normally light near thecentre, but tend to be stronger towardsthe outer edges. 3. � outer wing the partof the wing nearest the tipouter markerouter marker /�aυtə �mɑ�kə/ nounan ILS marker beacon, usually on cen-tre line of approach at about 4.5 nmfrom the runway thresholdoutflowoutflow /�aυtfləυ/ noun flow in anoutward direction � The outflow valve iscontrolled by the cabin pressure con-troller.outgoingoutgoing /aυt|�$əυŋ/ adjective goingout � There is a fall of temperature untilabout one hour after dawn when incom-ing solar radiation balances outgoingterrestrial radiation. Opposite incom-ingoutletoutlet /�aυtlət/ noun a passage for exitor escape � The air leaves the compres-sor outlet and passes through a matrixassembly of the secondary heatexchanger. � When the controllingsuper-charger outlet pressure isreached, the capsule is compressed suf-ficiently to open its bleed valve.outlineoutline /�aυtlan/ noun 1. a linearound the shape of something � Warn-ing labels have a solid red outline. 2. ashape � At low level, features are mosteasily recognised from their outline inelevation. � Cumulus cloud hasdetached domes or towers which aregenerally dense and have sharp out-lines. � verb to explain simply andbriefly � The changes in conditions out-lined in the next paragraph.


165 overloadout-of-balance turnout-of-balance turn /�aυt əv�b�ləns �t%�n/ noun a turn in which theaircraft ‘skids’ upwards and outwardsfrom the turn or ‘slips’ inwards anddownward � During an out-of-balanceturn, the ball in the slip indicator will bedeflected to the left or right.out of trimout of trim /�aυt əv �trm/ adjectivereferring to a situation in which the air-craft is not in static balance in pitch, sothat if the pilot releases the yoke or con-trol stick, the aircraft will start to climbor descendoutputoutput /�aυtpυt/ noun the product of aprocess � Air density will affect the out-put of the engine. � The function of thesupercharger is to increase the poweroutput. � The power output of an enginedepends on the weight of mixture whichcan be burnt in the cylinders in a giventime.outriggeroutrigger /�aυtr$ə/ noun a projec-tion attached to an aircraft to stabilise itor to support somethingoutwardoutward /�aυtwəd/ adjective movingaway from the centre or starting point �The piston draws fluid into the cylinderson the outward stroke and expels fluidinto the system on the inward stroke. �

boundoutwardsoutwards /�aυtwədz/ adverb awayfrom the centre or starting point,towards the outside � The door opensoutwards. (NOTE: The US English isoutward.)overalloverall /�əυvər |�ɔ�l/ adjective includ-ing everything � The total aerodynamiclosses result in an overall turbine effi-ciency of 92%. � Although the studentfailed in one of the five exams, her over-all result was a pass. � adverb generally� Overall, the test flight was a success.� noun /�əυvərɔ�l/ a one-piece item ofprotective clothing � The engineer waswearing an overall to prevent hisclothes from getting dirty.overallsoveralls /�əυvərɔ�lz/ plural noun pro-tective trousers with a bib and strapsover the shoulders � Wear overalls toprotect your clothes.overcomeovercome /�əυvə|�k�m/ verb to beat,to conquer, to win against � The effectsof anoxia at high altitudes can be over-

come by breathing through a mask. �

Drag must be overcome with thrust inorder for an aircraft to increase speed.overflewoverflew /�əυvə|�flu�/ � overflyoverflightoverflight /�əυvəflat/ noun the flightof an aircraft over an areaoverflyoverfly /�əυvə |�fla/ verb to fly over anarea (NOTE: overflew – overflown)overhangoverhang /�əυvəh�ŋ/ noun 1. thedistance from the last outer strut to theend of a monoplane’s wing 2. a distanceequivalent to half of the difference inthe spans of the two wings of a biplaneoverhauloverhaul verb /�əυvə|�hɔ�l/ to takeapart and examine carefully in order torepair and clean, etc. � To overhaul thesystem will take a couple of days. �

noun /�əυvəhɔ�l/ the act of taking apartin order to repair and clean � Other thanthe oil pump and the generator rotor,there are no other moving parts in thesystem to wear or which require peri-odic overhaul.overheadoverhead /�əυvə|�hed/ adjective 1.vertically above the point where acourse is measured or timed � The air-craft started from overhead A at 1000hours on a heading of 230°T. 2. abovethe level of people’s heads � Overheadbaggage lockers must be secured imme-diately prior to take-off. � adverb aboveone’s head � She noticed a plane flyingoverhead.overheatoverheat /�əυvə|�hi�t/ verb to get toohot � An acceleration/deceleration con-trol is fitted to prevent the turbineassembly from overheating duringacceleration, and to prevent flame-outduring deceleration.overlapoverlap noun /�əυvəl�p/ part of onething covering something else � verb/�əυvə |�l�p/ to have an area or range incommon with something else, or tocover part of something else � The mapsoverlap each other at the edges by threecentimetres. (NOTE: overlapping –overlapped)overloadoverload noun /�əυvələυd/ an exces-sive amount of work or electricity �

Resettable circuit protective devicesshould be designed so that when anoverload or circuit fault exists, they willopen the circuit. � verb /�əυvə|�ləυd/ 1.


overload operations 166

to load a device or system, such as anelectrical circuit, with too much work;to demand more than a system is capa-ble of � Operating pressure is main-tained in that part of the system whichleads to the selector valves, and somemethod is used to prevent overloadingthe pumps. 2. to load too heavily � Theaircraft failed to gain height after take-off because it was overloaded.overload operationsoverload operations /�əυvələυd�ɒpəreʃ(ə)nz/ noun operation of air-craft in unusual situations when take-off weight exceeds the permitted maxi-mumoverrideoverride /�əυvə|�rad/ verb to takeover control of the operation of an auto-matic device or system � A circuit-pro-tective device must not be of a typewhich can be overridden manually.(NOTE: overriding – overrode – over-ridden)overrunoverrun /�əυvər�n/ noun a clearedlevel area at the end of a runway, avail-able in case a plane does not stopquickly enoughovershootovershoot /�əυvə |�ʃu�t/ verb to flypast a target � The pilot tried to land butthe aircraft overshot the runway. (NOTE:overshooting – overshot)overspeedoverspeed verb /�əυvə |�spi�d/ to gotoo fast � A fault in the constant speeddrive unit causes the generator to over-speed. � noun /�əυvəspi�d/ a speed thatis too fast � Overspeed is usually a faultin the constant speed drive unit whichcauses the generator to overspeed.overspeedingoverspeeding /�əυvə |�spi�dŋ/ nounthe act of going too fast � Overspeedingof the engine is prevented by a governorin the fuel system.overstressoverstress /əυvə |�stres/ verb to sub-ject to too much force � It takes less gforce to overstress a heavy aircraft thana light one.

owing to

owing to /�əυŋ tu�/ prepositionbecause of � Integral tanks are nowfavoured for aircraft owing to the veryhigh utilisation of space and saving ofweight. � Owing to the aerodrome beingunserviceable, the landing was made atanother aerodrome some distanceaway.oxidation

oxidation /�ɒks|�deʃ(ə)n/ noun thecombination of a substance with oxy-gen, with loss of electrons � When alu-minium surfaces are exposed to theatmosphere, a thin invisible oxide skinforms immediately that protects themetal from further oxidation.oxide

oxide /�ɒksad/ noun a compound ofan element with oxygen � When alu-minium surfaces are exposed to theatmosphere, a thin invisible oxide skinforms immediately that protects themetal from further oxidation.oxidise

oxidise /�ɒksdaz/, oxidize verb toform an oxide by the reaction of oxygenwith another chemical substance � Overa period of time, the metal is oxidised bycontact with air.oxygen

oxygen /�ɒksd"ən/ noun a colour-less, odourless gas, which is essential tohuman life, constituting 21% by volumeof the Earth’s atmosphere � Our bodiescan get oxygen through the lungs. � Atvery high altitudes the flying pilot mustbe on oxygen at all times, unless an air-craft dispensation has been obtained.(NOTE: The atomic number of oxygen is8.)ozone

ozone /�əυzəυn/ noun a poisonousform of oxygen found naturally in theatmosphere which is toxic to humans atconcentrations above 0.1 parts per mil-lion � The maximum concentration ofozone is between 20 and 25 km abovethe Earth’s surface. Symbol O3


PPAPA abbreviation public addressPacific Standard TimePacific Standard Time /pə|�sfk�st�ndəd �tam/ noun the time zone ofthe west coast area of the USA and Can-ada, 8 hours behind Greenwich MeanTimepackpack /p�k/ noun 1. a detachable sys-tem � Circuit packs consist of basicdecision-making elements, referred toas logic gates, each performing combi-national operations. � A power packsystem is one in which most of the majorcomponents, with the exception of theactuators and, in some systems, thepumps, are included in a self-containedunit. 2. a small package containing a setnumber of items � The survival packincludes heliographs, sea marker dyes,day/night distress flares and parachuteflares.padpad /p�d/ noun same as helipadpairpair /peə/ noun two matched items,similar in appearance and function � Abrake control valve usually containsfour elements, one pair for the brakeson each side of the aircraft, to provideduplicated control.pancakepancake /�p�nkek/ (informal ) nounsame as pancake landing � verb tomake a pancake landing, or cause anaircraft to make a pancake landingpancake landingpancake landing /�p�nkek�l�ndŋ/ noun a landing in which anaircraft drops suddenly straight to theground from a low altitude, usuallybecause of engine failurepanelpanel /�p�n(ə)l/ noun 1. a flat, oftenrectangular piece of the skin of the air-craft � Access to the engine compart-ment is normally via hinged cowling

panels. 2. a board with switches, dials,control knobs, etc. � The pilot is trainedto scan an instrument panel.panic

panic /�p�nk/ noun a sudden over-powering fear or terror � In order toprevent mass panic amongst passengersin an emergency situation, crew mayhave to use force.PAPI

PAPI abbreviation precision approachpath indicatorPAR

PAR abbreviation precision approachradarparachute

parachute /�p�rəʃu�t/ noun a deviceused to slow down free fall from an air-craft, consisting of a light piece of fab-ric attached by cords to a harness andworn or stored folded until used indescentparachute flare

parachute flare /�p�rəʃu�t fleə/noun a distress signal, suspended froma parachute to allow more time for theflare to be seen, which is fired to aheight of 1200 ftparachutist

parachutist /�p�rəʃu�tst/ noun aperson who returns to the ground froman aircraft using a parachuteparallel

parallel /�p�rəlel/ adjective 1. side byside and having the same distancebetween them at every point � As oneaircraft flew round to attempt anotherlanding, a Boeing 757 was taking off onthe parallel runway. � The runway isparallel to the main road. 2. � in paral-lel arranged so as to join at commonpoints at each end � When batteries areconnected in parallel, voltage remainsconstant but capacity increase. � noun aline which is parallel to another � par-allels of latitude imaginary lines of


parameter 168

constant latitude around the Earth’s sur-faceparameterparameter /pə|�r�mtə/ noun a set ofmeasurable values such as temperaturewhich define a system and determine itsbehaviour � Parameters required by thecrew to set and monitor engine thrustare permanently displayed on thescreen.parasite dragparasite drag /�p�rəsat dr�$/noun a component of total lift, causedby friction between the airflow and thestructure of the aircraft � Parasite dragincreases as speed increases.parcelparcel /�pɑ�s(ə)l/ noun a small pack-age � parcel of air small body of air �

When a parcel of air is heated, its vol-ume increases and its density decreasesthus there is a fall in pressure.parkpark /pɑ�k/ verb to leave a vehiclesuch as a car or an aircraft in a particularplace when no one is using it � Parkbeside the Cessna 150.parking brakeparking brake /�pɑ�kŋ brek/ nouna brake that is set, often by hand, whenthe aircraft is stationary for a period oftime � Make certain that the parkingbrake is on before doing engine run-upchecks. � Light aircraft should be leftwith parking brakes off so that they canbe moved quickly in the event of a fire inthe hangar.partialpartial /�pɑ�ʃ(ə)l/ adjective in part, notfully � partial closing of an undercar-riage door not full closing of the doors� partial filter blockage incompleteblockage of a filterparticleparticle /�pɑ�tk(ə)l/ noun a verysmall piece or part � Solid particles inthe atmosphere include sand, dust, vol-canic ash and atmospheric pollution. �

Hailstones start as ice particles in theupper part of a cumulonimbus cloud.particularparticular /pə |�tkjυlə/ adjective spe-cial, given, distinct, not general � a par-ticular time � a particular speed � Thesize and number of valves required for aparticular type of aircraft is governedby the amount of air necessary for pres-surisation and air conditioning.passpass /pɑ�s/ noun 1. a badge or docu-ment which allows one to enter arestricted or prohibited area � a security

pass 2. a successful result in an exam �

verb 1. to move � Tropical storms dissi-pate as they pass from sea to land. � Theair leaves the compressor outlet andpasses through a matrix assembly. 2. �to pass information to give informa-tion � pass your message an instructionto a pilot to give information via radioto an air traffic control facility 3. � topass an exam to be successful in anexam 4. � to pass a book to someone topick up and give a book to somebodynearby 5. � to pass another aircraft tomove past another aircraftpassage

passage /�p�sd"/ noun 1. move-ment over, along, or through something� The passage of air over a turbine isused to power a small emergency gen-erator. � The passage of a trough ismarked by a sharp veer in the wind. 2. achannel through which something canpass � Liquid cooling is achieved by cir-culating a liquid around the cylinderbarrels, through a passage formed by ajacket on the outside. 3. part of a bookor speech, etc. � a passage from a train-ing manualpassenger

passenger /�p�snd"ə/ noun a per-son who travels in an aircraft, car, train,etc., and has no part in the operation ofit � The Piper Archer has seating for apilot and three passengers.passenger aircraft

passenger aircraft /�p�snd"ə�eəkrɑ�ft/ noun an aircraft speciallydesigned for carrying peoplepassive

passive /�p�sv/ adjective receivingan action but taking no action � In pri-mary radar systems, the target is pas-sive. � passive state referring to a sys-tem or device which may be switchedon or ‘live’ but not reacting to any input.Opposite activepass-mark

pass-mark /�pɑ�s mɑ�k/ noun themark which separates those who failand those who pass an examinationpassport control

passport control /�pɑ�spɔ�t kən |

�trəυl/ noun 1. the action of checkingpassports of people arriving in or leav-ing a country � We now have to gothrough passport control. 2. the placewhere passports are checked when peo-ple arrive in or leave a country � At


169 period

passport control, a customs officialchecks passports.patchpatch /p�tʃ/ noun a small area � apatch of fog � a patch of cloud � Patchesof early morning fog made identifica-tion of ground features difficult.pathpath /pɑ�θ/ noun a route or coursealong which something moves � Pro-jection of the path of the aircraft overthe ground is called its track.patternpattern /�p�t(ə)n/ noun a form ormethod which shows particular, con-sistent characteristics � pressure pat-tern changes in pressure areas whichtake place regularly, e.g. every yearpavementpavement /�pevmənt/ noun a pre-pared concrete or tarmac surface forground manoeuvring of aircraft, includ-ing taxiways and runways (NOTE: Thebearing strengths of pavementsintended for aircraft of 5,700 kg MTWA(maximum total weight authorised) orless are reported as the maximumallowable weight and maximum allowa-ble tyre pressure.)pavement classification numberpavement classificationnumber /�pevmənt �kl�sf |

�keʃ(ə)n �n�mbə/ noun a numberexpressing the bearing strength of apavement for unrestricted operations.Abbreviation PCNPAXPAX abbreviation passengerspayloadpayload /�peləυd/ noun the money-earning load carried by the aircraftincluding the passengers, baggage andfreight � The shape of an aircraft isdetermined by the requirement to pro-vide an aerodynamic lift force greatenough to support the weight of the air-craft and payload whilst in flight.PCNPCN abbreviation pavement classifica-tion numberPDCPDC abbreviation pre-departure clear-ancepeakpeak /pi�k/ noun the highest point �

The intensity of solar radiation reachesa peak around noon. � peak value max-imum valuePEDPED abbreviation portable electronicdevicepedalpedal /�ped(ə)l/ noun a foot-operatedlever

penalty

penalty /�pen(ə)lti/ noun 1. anunwanted result of an action � The pen-alty of using a circular polarisationtransmission may be some loss of defi-nition. 2. a punishment or fine � Fuelpenalties can be incurred if fuel surplusto requirements is carried.penetrant

penetrant /�penətrənt/ noun some-thing which forces or gets entry into anarea or substance � Penetrant dyeinspection is a non-destructive test usedmainly for the detection of defects opento the surface. � Penetrant oil can beused to loosen rusty bolts, etc.penetrate

penetrate /�pentret/ verb to force away into � Cool air from the Atlanticcan sometimes penetrate far intoEurope. � Occasionally, thunder cloudwill penetrate through the tropopause.penetration

penetration /�pen|�treʃ(ə)n/ nounthe act of forcing a way into or through� Long-range radars are little affectedby weather interference and have goodcloud penetration characteristics.per

per /p%�, pə/ preposition for each, forevery � feet per minute (fpm) � gallonsper hour (gph)per centper cent /pə �sent/ noun the numberout of each hundred � fifty per cent(50%) half or ½ or 50 out of 100 �twenty-five per cent (25%) one quar-ter or ¼ or 25 out of 100percentage

percentage /pə |�sentd"/ noun 1. afraction with 100 as the understooddenominator � Volumetric efficiency isusually expressed as a percentage. 2.part of the total � Only a small percent-age of passengers take in the pre-depar-ture safety briefing.perform

perform /pə|�fɔ�m/ verb to do � Cir-cuit breakers perform the same functionas a fuse. � The pilot performed a loopto conclude his flying display.performance

performance /pə |�fɔ�məns/ noun theability of a system such as an aircraft oran engine to function as required � Theperformance of the turbojet engine ismeasured in thrust produced at the pro-pelling nozzle or nozzles.period

period /�pəriəd/ noun a length oftime � a 24 hour period � a period of 3minutes


periodic 170periodicperiodic /�pəri|�ɒdk/ adjective hap-pening from time to time or at regularintervals, occasional � periodic main-tenance maintenance made at a partic-ular time interval � Periodic calibrationof ILS (instrument landing system)installations is recommended.peritrackperitrack /�peritr�k/ noun same astaxiwaypermanentpermanent /�p%�mənənt/ adjectivelasting or remaining without change �permanent deformation damage to astructure which must be repaired byreplacing the damaged part � perma-nent magnet a metal component whichalways has a magnetic influence. Oppo-site temporarypermissiblepermissible /pə |�msb(ə)l/ adjectiveallowable, not prohibited � Great caremust be taken to ensure that the aircraftoperates within regulated or permissi-ble weight limits.permissionpermission /pə |�mʃ(ə)n/ noun con-sent or authorisation � A passenger whois drunk can be refused permission toboard the aircraft.permitpermit noun /�p%�mt/ a document orpass that is proof of official permissionto do or have something � You need apermit to enter the restricted area. �

verb /pə|�mt/ to allow � When oxygenmask are pulled down to the usableposition, valves are opened which per-mit oxygen to flow. � Informationpassed to the operations departmentwill be sufficient to permit the flight tobe planned.Permit to FlyPermit to Fly /�p%�mt tə �fla/ nouna certificate issued by the Civil AviationAuthority in the UK for aircraft whichdo not qualify for a Certificate of Air-worthinessperpendicularperpendicular /�p%�pən|�dkjυlə/adjective at right angles or 90° to a baseor a line � The vertical grid lines areperpendicular to the horizontal ones. �

The air is acted upon by a force perpen-dicular to the isobars in the direction oflow pressure.persistpersist /pə|�sst/ verb 1. to continue toexist � Snow cover tends to persist onnorth-facing slopes of mountains. 2. tocontinue without giving up � She per-

sisted with her request until it wasgranted.persistencepersistence /pə|�sstəns/ noun 1. thefact of continuing to exist and not disap-pearing � The persistence and move-ment of cols is governed by the move-ment of the adjacent pressure systems.2. the act of continuing to do somethingand not giving up � He managed toovercome his difficulties through per-sistence and hard work.personnelpersonnel /�p%�sə|�nel/ noun a bodyof people involved in a common pur-pose such as work � Smoke masks areavailable for use by personnel withinthe aircraft.PFCUPFCU abbreviation power flying con-trol unitPFDPFD abbreviation primary flight dis-playphasephase /fez/ noun 1. a stage or part �

An emergency situation may occur dur-ing any phase of the flight. 2. the rela-tionship between voltage and current �

The CSDU (constant speed drive unit)drive shaft turns the permanent magnetgenerator and single phase AC (alter-nating current) is induced in the wind-ing on the stator.phase anglephase angle /�fez ��ŋ$(ə)l/ nounthe difference between two periodicphenomena expressed as an anglephase differencephase difference /�fez�df(ə)rəns/ noun a measure of phaseangle from any VOR radial related tothat on bearing 360°phenomenonphenomenon /fə |�nɒmnən/ noun anoccurrence or circumstance which canbe perceived by the senses � Metalfatigue is not a modern phenomenon. �

Of all meteorological phenomena,thunderstorms present the greatest haz-ard to aviation. (NOTE: The plural formis phenomena.)photographic filmphotographic film /�fəυtə$r�fk�flm/ noun a celluloid material usuallycontained in a small metal cylindricalcasing for use in camerasphysicalphysical /�fzk(ə)l/ adjective 1.referring to matter and energy or thesciences dealing with them, especiallyphysics � Oxygen and nitrogen togetherconstitute 99% of the atmosphere and


171 pitch trim

obey the physical laws as any other gas.2. referring to the human body � Insome aircraft operating for long peri-ods at high altitudes, physical discom-fort may arise from low relative humid-ity. � physical fitness the state of healthof the bodyPIC

PIC abbreviation pilot in commandpiece

piece /pi�s/ noun a bit, portion or part� The upper and lower skin panel ofeach wing can be made in one piece.(NOTE: Piece is often used to show oneitem of something which has no plural:a piece of equipment; a piece of infor-mation.) � piece of equipment an itemof equipment � Early rescue depends onrapid location of survivors and the sur-vival beacon is the most importantpiece of equipment in this regard.pilot

pilot /�palət/ noun 1. a person whooperates an aircraft in flight 2. the partof a system or device that leads thewhole � verb to operate or guide � topilot an aircraft

COMMENT: A pilot holding a private orcommercial pilot’s licence may log aspilot-in-command time only the flighttime during which he or she is the onlyoperator of the aircraft’s flyingcontrols.

pilot in command

pilot in command /�palət n kə |

�mɑ�nd/ noun the pilot who has respon-sibility for the operation and safety ofthe aircraft during flight time. Abbrevi-ation PICPilot’s Operating Handbook

Pilot’s Operating Handbook/�paləts �ɒpəretŋ �h�ndbυk/ noun abook giving details of an aircraft withrecommendations and instructionsregarding its use. Abbreviation POHpin

pin /pn/ noun a short, usually cylindri-cal metal rodpinpoint

pinpoint /�pnpɔnt/ noun a visualobservation of the precise position of anaircraft � The pinpoint is a very positivemeans of establishing position, as longas the feature is properly identified. �

verb to draw attention to � to pinpoint aproblempipe

pipe /pap/ noun a hollow cylinder ortube to convey a fluid � a delivery pipe� an exhaust pipe

pipeline

pipeline /�paplan/ noun a long hol-low cylinder or tube to convey a fluidsuch as oil or natural gas � The incom-pressibility of liquids enables force tobe transmitted long distances throughpipelines.piston

piston /�pstən/ noun a solid cylinderthat fits into a larger cylinder and movesunder fluid pressure, as in petrol anddiesel engines or compresses fluids, asin pumps and compressorspiston engine

piston engine /�pstən �end"n/noun a petrol or diesel engine in whichpistons are moved by combustion offuel, this reciprocating movement pro-ducing rotating movementpiston ring

piston ring /�pstən rŋ/ noun one ofthe metal rings which seals the spacebetween the piston and the cylinder wall� There should be a loose fit betweenthe cylinder and the piston, the differ-ence being taken up by the piston rings.pitch

pitch /ptʃ/ noun 1. a nose up/downmovement of the aircraft about its lat-eral axis � If the control column ismoved forward or aft, the pitch attitudeof the aircraft changes. 2. the distance apropeller would advance in one rotationif there was no slip � fine pitch settingand coarse pitch setting angular pro-peller-blade settings � Variable pitchpropellers were originally producedwith two blade-angle settings – finepitch to enable full engine speed to beused on take off and coarse pitch toallow an economical engine speed to beused for cruising. � verb to move aboutthe lateral axis � Move the yoke fore andaft to pitch down and up.pitch angle

pitch angle /�ptʃ ��n$(ə)l/ noun theangle between the blade element chordline and the plane of rotation of the pro-pellerpitch lock

pitch lock /�ptʃ lɒk/ noun a means ofholding the fine pitch stop in a pre-scribed position (NOTE: Some manufac-turers use the term to describe a devicewhich locks the blades at whateverangle they are at if there is a failure ofthe pitch change mechanism.)pitch trim

pitch trim /�ptʃ trm/ noun the trimof the aircraft in the lateral axis so that


pitot head 172

there are no forward/aft forces on thecontrol stick or yokepitot headpitot head /�pi�təυ hed/ noun anexternally mounted device whichsenses and sends airspeed informationto the airspeed indicator in the cockpitpitot-static systempitot-static system /�pi�təυ�st�tk �sstəm/ noun a pressure sys-tem for the airspeed indicator, altimeterand vertical speed indicatorpitot tubepitot tube /�pi�təυ tju�b/, Pitot tubenoun an open-ended tube used to meas-ure the speed of flow of a fluid � deviceto sense pitot pressure created by themovement of air over the aircraftpivotpivot /�pvət/ noun a short rod onwhich another part rotates � verb to turnon a point � The rocker arm pivots on abearing and opens the valve.placeplace /ples/ noun 1. a space or area �Greenwich is a place on the 0° merid-ian. 2. a position � decimal place 3. � inplace of instead of � to take place tohappen � The explosion took place justbefore the aircraft landed. � verb to put� Place the chart on the seat next to you.� Rotate the grid to place the winddirection under true.plainplain /plen/ adjective without patternor marking or writing � a plain sheet ofpaper a sheet of paper with nothing onitplanplan /pl�n/ noun 1. a drawing or dia-gram of a place viewed from above �

The horizontal situation indicatorpresents a selectable dynamic colourdisplay of flight progress and plan vieworientation. 2. a scheme or programmeworked out in advance of putting some-thing into operation � verb to organise ascheme or programme � Jeppesencharts are used to plan and fly a saferoute to a destination.planeplane /plen/ noun 1. an imaginarysurface containing all the straight linesthat connect any two points on it � Theplanes of parallels of latitude are paral-lel to the plane of the equator. � Thepitch angle is the angle between theblade element chord line and the planeof rotation of the propeller. 2. an aero-plane (NOTE: Because of possible con-fusion with meaning 1, plane as in

meaning 2 is considered bad usage bysome. The word aircraft is preferred inthat case.)planningplanning /�pl�nŋ/ noun makingplans � The instructor gave a talk onflight planning.plan position indicatorplan position indicator /�pl�n pə |

�zʃ(ə)n �ndketə/ noun the normaltype of display for a radar signal, whichresembles a map with the radar site atthe centreplantplant /plɑ�nt/ noun large and usuallyheavy equipment or tools used for doingsomethingplateplate /plet/ noun a smooth, flat rigidobject with the same thickness all over� The basic construction of a lead-acidcell consists of a positive electrode andnegative electrode, each of which ismade up of lead-antimony alloy gridplates.play

play /ple/ noun a slightly loose fittingof engineering parts which allows themto move freely � Some play should befelt in the aileron actuator rod linkage.� verb � to play a part to be part of awhole which has an effect on something� Contrast and colour play a part inidentifying coastlines.plotplot /plɒt/ noun a graph or diagramthat shows a relationship between twosets of numbers as a series of pointsjoined by a line � a plot of applied stressand resulting strain � verb to calculateand mark a line on a graph or chart, etc.� to plot a course to calculate and drawthe desired route of an aircraft on achartplugplug /pl�$/ noun 1. a device for mak-ing an electrical connection � Alternat-ing current ground power can be fittedto an aircraft via a six-pin groundpower plug. � a 3-pin plug an electricalsupply plug with three electrodes: live,neutral and earth 2. a device for ignitingfuel in an engine � An electric sparkfrom an igniter plug starts combustion.� The fuel/air mixture is ignited by aspark plug. 3. a device to prevent liquidflowing out of a container � oil drainplug � spark plug � verb 1. � to plug ahole to fill a hole so that fluid cannotescape 2. � to plug something in to


173 polarity

make an electrical connection, often byinserting the plug on an electricaldevice such as a computer into an elec-trical supply socketplungerplunger /�pl�nd"ə/ noun a machinepart that operates with a thrusting orplunging movement, e.g. a piston � Aflow indicator valve comprises a body,a spring-loaded plunger connected toan actuator arm, and a micro-switch.plusplus /pl�s/ preposition increased,added to � At the selected decisionheight plus 50 feet, an aural alert chimesounds. � Four plus four equals eight (4+ 4 = 8).PMSPMS /�pi� em �es/ abbreviation per-formance management systempneumaticpneumatic /nju�|�m�tk/ adjectiveoperating by means of air under pres-sure or compressed air � High-pressurepneumatic systems are generally fittedon the older types of piston-engine air-craft to operate the landing gear, wingflaps, wheel brakes.pneumaticallypneumatically /nju� |�m�tkli/adverb by using air under pressure orcompressed air � Clamshell doors arehydraulically or pneumatically opened.PNRPNR abbreviation point of no returnPOBPOB abbreviation persons on boardpocketpocket /�pɒkt/ noun same as airpocketpodpod /pɒd/ noun a streamlined casingor housing � The engine bay or pod isusually cooled by atmospheric air.POHPOH abbreviation Pilot’s OperatingHandbookpointpoint /pɔnt/ noun 1. a particular fig-ure on a scale � The melting point of iceis 0°C (Celsius). 2. a particular place �a point on a map a particular place ona map 3. the sharp end of something � apencil point � verb 1. to direct towards� Point the aircraft towards the airfield.2. to indicate direction, often with a fin-ger � point to the east 3. � to point outto draw attention to � The instructorpointed out the dangers of not keeping agood lookout.pointerpointer /�pɔntə/ noun an indicatingdevice on an instrument, e.g. a needle �The pointer centralises to indicate that

the aircraft is aligned with the runwaycentre line.point of no returnpoint of no return /�pɔnt əv nəυ r|

�t%�n/ noun a place on the route wherethe aircraft does not have enough fuel toreturn to the starting place � The pointof no return is calculated before depar-ture to cover the chance that both theterminal airfield and its alternatebecome unavailable during flight.Abbreviation PNRpolarpolar /�pəυlə/ adjective 1. located in orcoming from the region around thenorth or south pole � polar air � a polarregion � The greatest horizontal gradi-ents of mean temperatures of a layer arefound at the boundaries between coldpolar and warm tropical air masses. 2.referring to the pole or poles of an elec-trical device or of a magnet � Bar mag-nets attract each other because of polardifferences.polar diameterpolar diameter /�pəυlə da|��mtə/noun the distance from one pole, pass-ing through the centre of the Earth, tothe other pole � The Earth’s polardiameter is shorter than its averageequatorial diameter.polar ice cappolar ice cap /�pəυlə �as �k�p/noun the permanent area of ice at northor south polepolarisationpolarisation /�pəυləra |�zeʃ(ə)n/,polarization noun 1. a characteristic oflight or radio or other electromagneticwaves in which the waves are aligned inone direction and show different prop-erties in different directions � Theantenna must have the same effectivelength and the same polarisation as thetransmitter. 2. partial or complete polarseparation of positive and negative elec-tric chargepolarisepolarise /�pəυləraz/, polarize verb1. to align in one plane � The frequencyallocation for VOR (very high fre-quency omni-directional radio range) is108–117.975 MHz (megahertz) andtransmissions are horizontally polar-ised. 2. to separate positive and negativeelectric chargespolaritypolarity /pəυ|�l�rti/ noun the direc-tion of flow of flux or current in anobject � During discharge, when the


pole 174

polarity of the supply changes, thestored energy is returned to the supply.� polarity test a test to see which termi-nal is positive and which is negativepolepole /pəυl/ noun 1. the north or southpoint of the Earth’s axis � A meridian isa line joining pole to pole. 2. a terminal,e.g. of a battery � negative pole � posi-tive pole 3. a long, rounded piece ofwood or metal � a flag polepollutionpollution /pə |�lu�ʃ(ə)n/ noun the pres-ence of unusually high concentrationsof harmful substances in the environ-mentpontoonpontoon /pɒn |�tu�n/ noun same asfloatpoorpoor /pɔ�/ adjective bad � poorweather conditions � poor visibility �

Air is a poor conductor.poppet valvepoppet valve /�pɒpt v�lv/ noun anintake or exhaust valve of a pistonengine, operated by springs and camsporousporous /�pɔ�rəs/ adjective referring tosubstances which allow fluid to passthrough them � The de-icing fluidpasses through a porous plastic sheet.portport /pɔ�t/ noun 1. an entrance whichis opened periodically � inlet port � Asa piston in the pump moves outwardsinto its cylinder, it covers the inlet portand forces fluid out of the top of the cyl-inder. 2. the left-hand side of an aircraftwhen facing forwards when inside theaircraft � Unless an aircraft is flying inthe same or exactly opposite directionto the wind, it will experience eitherport or starboard drift. Opposite star-boardportableportable /�pɔ�təb(ə)l/ adjective capa-ble of being carried in the hands � aportable fire extinguisher � The aneroidbarometer is a more portable devicethan a mercury barometer.portable electronic deviceportable electronic device/�pɔ�təb(ə)l �lektrɒnk d|�vas/ nouna piece of electronic equipment such asa mobile phone or laptop which is smallenough to be carried onboard an air-craft, and which may cause problemswith the aircraft’s systems during flight.Abbreviation PEDportionportion /�pɔ�ʃ(ə)n/ noun a part or sec-tion � A hailstone starts as a small ice

particle in the upper portion of a cumu-lus cloud.position

position /pə |�zʃ(ə)n/ noun 1. a placeor location where something is � TheGreenwich or prime meridian and theequator are the axes of the systemcalled latitude and longitude which isused for expressing position on theEarth. 2. the setting of a control, etc. �

the neutral position 3. � in a sittingposition seated � verb to place some-thing in a special location � The mag-netic compass is positioned away frommagnetic sources.position line

position line /pə|�zʃ(ə)n lan/ nouna line along which an aircraft is knownto be at a particular time, usually by tak-ing a VOR bearing. Also called line ofposition, navigational lineposition report

position report /pə |�zʃ(ə)n r|�pɔ�t/noun a report over a known location astransmitted by an aircraft to an air traf-fic control stationpositive

positive /�pɒztv/ adjective 1. defi-nite, without doubt � The pinpoint is avery positive means of establishing air-craft position. 2. referring to a numbergreater than zero � Oil is ducted to thefront of the pitch change piston and theblades move to a positive angle. 3.referring to the + symbol � positive ter-minal the terminal of a battery marked+positive idling speed

positive idling speed /�pɒztv�ad(ə)lŋ �spi�d/ noun idling speedselected with the throttle to ensure thatthe engine runs correctly without sparkplug fouling � An adjustable stop on thethrottle control ensures a positive idlingspeed.possibility

possibility /�pɒs|�blti/ noun achance occurrence � Anti-braking sys-tems are designed to prevent the wheelsfrom locking during landing thus reduc-ing the possibility of wheel skid.possible

possible /�pɒsb(ə)l/ adjective capa-ble of happening � If possible, controlsurfaces should be moved by hand. �

There will be a possible delay. � Fire ina toilet could present difficulties due tothe confined space and possible smokeaccumulation.


175 precautionpotential

potential /pə |�tenʃəl/ adjective capa-ble of being, but not yet in existence � Adesignated fire zone is a region where apotential fire risk may exist. � potentialdanger possible future danger � nounvoltage � Precipitation static developsdue to friction between the aircraft sur-face and precipitation causing the air-craft to become charged to a highpotential.pound

pound /paυnd/ noun a unit of weightequal to 16 ounces or 453.592 grams.Abbreviation lbpowder

powder /�paυdə/ noun a substancemade of ground or otherwise finely dis-persed solid particles � Dry chemicalfire-extinguishers contain a non-toxicpowder.power

power /�paυə/ noun energy or forcepower-assisted

power-assisted /�paυə ə |�sstd/adjective � power-assisted controlscontrols which require less humaneffort to movepower dive

power dive /�paυə dav/ noun a steepdive made by an aircraft with its enginesat high power to increase the speedpowered

powered /�paυəd/ adjective driven bysomething such as a type of energy ormotor � system powered by electricitypower linepower line /�paυə lan/ noun a thickcable, supported by pylons, which car-ries electricity for long distancespowerplant

powerplant /�paυəplɑ�nt/ noun anengine used to move a vehicle or air-craft � Additional strength is requiredfor the powerplant attachment point.(NOTE: The word also written powerplant.)

‘…by replacing the Rotax engine with afour-stroke Jabiru powerplant, the aircraftdesigners claim the aircraft will beprovided with more power and increasedall-round performance’ [FlightInternational 16–22 July 1997]

power supply

power supply /�paυə sə |�pla/ nounan electrical circuit that provides partic-ular direct current voltage and currentlevels from an alternating currentsource for use in other electrical circuits� If the power supply from the amplifierto the gauge fails, the needle slowlyfalls to zero.

PPI

PPI abbreviation plan position indica-torPPL

PPL abbreviation Private Pilot’sLicencePPR

PPR abbreviation prior permissionrequiredPR

PR abbreviation public relationspracticable

practicable /�pr�ktkəb(ə)l/ adjec-tive capable of being put into practice oreffect � Some military aircraft use brak-ing parachutes but this is not practica-ble on civil aircraft.practical

practical /�pr�ktk(ə)l/ adjectivereferring to practice or action ratherthan theory � For practical purposes,any straight line drawn on a Lambert’sconformal projection represents a greatcircle.practice

practice /�pr�kts/ noun 1. habitualor customary behaviour � It is commonpractice for pilots to take turns to sleepon long-haul flights. 2. a performanceor operation � in practice when actu-ally done, in reality � Frequency modu-lation (FM) in theory has a limitlessnumber of sidebands, but in practiceonly the first eight pairs are significant.� verb US same as practise

‘…if the aircraft has been standingovernight or longer, check the drains forwater. This should, of course, be normalpractice’ [Civil Aviation Authority,General Aviation Safety Sense Leaflet]

practise

practise /�pr�kts/ verb to do some-thing repeatedly in order to improve �

In order to improve flying skills, atrainee pilot must practise regularly.(NOTE: This word is also written prac-tice in US English.)pre-

pre- /pri�/ prefix beforepre-arrange

pre-arrange /�pri� ə|�ren"/ verb todecide or to plan in advance, to prede-termine � Selective calling uses thefour-letter code pre-arranged with thecontrolling authorities.precaution

precaution /pr |�kɔ�ʃ(ə)n/ noun anaction taken to prevent or avoid a dan-gerous situation or failure � Personnelconcerned with fuelling should takeevery precaution to prevent outbreaksof fire.


precede 176precede

precede /pr |�si�d/ verb to take placeor to come before something else � Aperiod of calm often precedes a storm. �When the RVR (runway visual range) isgreater than the maximum value whichcan be assessed, the group will be pre-ceded by the letter indicator P followedby the highest value which can beassessed.precedence

precedence /�presd(ə)ns/ noun thequality of being more important orurgent than something else � to takeprecedence over to have priority over,to be more important than � Emergencylandings take precedence over all oth-ers.preceding

preceding /pr |�si�dŋ/ adjective tak-ing place or coming before somethingelse � as mentioned in the precedingparagraph as written in the paragraphbefore the one being readprecipitation

precipitation /pr|�sp|�teʃ(ə)n/noun water falling as rain, drizzle, hail,sleet and snow from the atmosphereonto the surface of the Earth � Clouddroplets are small and light at first, butwhen the droplets grow and becomeheavier, they fall as precipitation. � Pre-cipitation is classified as light, moder-ate or heavy according to its rate of fall.precise

precise /pr|�sas/ adjective exact oraccurate � A pinpoint is an indication ofthe precise position of the aircraft. � Aprecise interval is essential to obtaincorrect ignition timing on all cylindersduring engine running.precision

precision /pr|�s"(ə)n/ noun exact-ness or accuracy � Precision flying isonly achieved by constant practice. �with precision with exactnessprecision approach path indicator

precision approach path indica-tor /pr|�s"(ə)n ə|�prəυtʃ pɑ�θ�ndketə/ noun a set of lights thatenables pilots to judge whether theirglide slope is correct on the finalapproach to landingprecision approach radar

precision approach radar /pr|

�s"(ə)n ə |�prəυtʃ �redɑ�/ noun aground-based primary radar system togive vertical and lateral informationabout an aircraft’s final approach path.Abbreviation PAR

precision area navigationprecision area navigation /pr |

�s"(ə)n �eəriə �n�v|�$eʃ(ə)n/ noun astandard of performance for navigationthat requires an aircraft to remainwithin 1 nautical mile of the centrelineof its course for 95% of the time.Abbreviation PRNAVpre-departurepre-departure /�pri� d |�pɑ�tʃə/adjective taking place before a depar-ture � Only a few passengers absorb thepre-departure safety information.pre-departure clearancepre-departure clearance /�pri� d |

�pɑ�tʃə �klərəns/ noun a message thatthe pilot must receive from air trafficcontrol before the plane is allowed totake offpredeterminepredetermine /�pri�d |�t%�mn/ verbto decide and set or fix beforehandpredeterminedpredetermined /�pri�d |�t%�mnd/adjective decided and set beforehand �

When the roll control knob is returnedto the central position, the aircraft rollsout on to a predetermined heading.predictpredict /pr |�dkt/ verb to foretell or tosay beforehand � Rain is predictedwithin the next hour. � Dead reckoningposition is the position of the aircraft aspredicted by calculation.predictablepredictable /pr |�dktəb(ə)l/ adjec-tive 1. reliably regular and thereforeforeseeable � Only the high frequencyband has predictable, reliable sky wavepropagation by day and by night. 2.capable of being foreseen, expected oranticipated � the accident was predict-able it was possible to know that theaccident would happen before it hap-penedpredictionprediction /pr |�dkʃən/ noun the actof saying what will happen in the future� The map display combines currentground speed and lateral accelerationinto a prediction of the path over theground to be followed over the next 30,60 and 90 seconds.predominancepredominance /pr|�dɒmnəns/noun greatest importance or influence �The predominance of a cold northerlyairstream during the winter months.predominantpredominant /pr|�dɒmnənt/ adjec-tive most important or influential, morepowerful than others � The ocean sur-face usually consists of a predominant


177 present

swell three or four feet high and 500 to1,000 feet between crests.predominatepredominate /pr |�dɒmnet/ verb tohave greater number or importance, orto be more powerful than others � Acold northerly airstream predominatesduring the winter months.preferprefer /pr|�f%�/ verb to like more, tofavour � Of the two basic types of fuelpump, where lower pressures arerequired at the burners, the gear-typepump is preferred because of its light-ness. (NOTE: preferring – preferred)preferablepreferable /�pref(ə)rəb(ə)l/ adjectivebetter than, more desirable � Threeposition lines are preferable to two. � Ifthere is a choice between two courses ofaction, the safest is the most preferable.preferencepreference /�pref(ə)rəns/ noun � inpreference to by choice, rather than �

For some applications, e.g. landinggear and flaps, hydraulic systems areused in preference to mechanical orelectrical systems.prefixprefix /�pri�fks/ noun part of a wordadded at the beginning of a word to alterthe meaning � Pre- is a prefix meaning‘before’. (NOTE: The plural form is pre-fixes.)

COMMENT: The prefixes for cloudtypes are: alto- medium level cloud(6,500 feet to 23,000 feet); cirro- highcloud (16,500 feet and above); nimbo-any height, but rain-bearing as forexample nimbostratus: rain carrying,low-level cloud; strato- low cloud (upto 6,500 feet).

pre-flightpre-flight /�pri� �flat/ adjective tak-ing place before a flight � pre-flightbriefing a short instructional talkbefore a flight � pre-flight checkschecks made on the aircraft structureand systems before taking off � Duringpre-flight checks, control surfacesshould be moved by hand to ascertainthat they have full and free movement. �noun the set of procedures and checksthat pilots and ground crew must carryout before an aircraft takes off � verb toinspect an aircraft before it takes off toensure that it is airworthypre-ignitionpre-ignition /�pri�$ |�nʃ(ə)n/ nounthe ignition of the fuel/air mixture in thecombustion chamber, occurring before

the spark � Pre-ignition is often causedby a hot spot in the combustion cham-ber which ignites the mixture.preparationpreparation /�prepə |�reʃ(ə)n/ nouna state of readiness or act of makingsomething ready for use beforehand �

Normal aircraft preparation are actionsand precautions taken by the cabin crewon every flight to ready the aircraft forany abnormal or emergency situationwhich may occur during any phase ofthe flight.prepareprepare /pr |�peə/ verb 1. to makeready beforehand for a particular pur-pose, as for an event or occasion � Theinstructor prepared the students for theexams. � prepare for take-off to getready for take-off 2. to make by puttingvarious elements or ingredientstogether � Regional area forecastingcentres use information about upperwind speeds and temperatures to pre-pare specific forecasts and significantweather charts.prescribeprescribe /pr|�skrab/ verb to setdown as a rule or a guide � prescribedprocedures a set or fixed pattern ofdoing something � A means of holdingthe fine pitch stop in a prescribed posi-tion is also called ‘pitch lock’.pre-selectpre-select /�pri�s|�lekt/ verb to selector to choose in advancepre-selectedpre-selected /�pri�s |�lektd/ adjec-tive selected or chosen in advance � TheCSU (constant speed unit) maintainsthe pre-selected propeller speed.presence

presence /�prez(ə)ns/ noun exist-ence � The presence of cloud by daydecreases the value of the maximumtemperatures. � A fuel sample hazy orcloudy in appearance would indicatethe presence of water.presentpresent /�prez(ə)nt/ adjective 1. inplace, existing � Fuel, oxygen and heatmust all be present for fire to exist. 2.the period in time through which we arenow living, between the past and thefuture � at the present time at thistime, now � present day aircraft mod-ern aircraft � present weather theweather at the moment of speaking �

verb /pr |�zent/ 1. to create or to make �A fire in a toilet could present difficul-


presentation 178

ties. � Learning to fly presents a chal-lenge. � to present an opportunity tocreate or to give an opportunity 2. togive a prize or award � Charter passen-gers on Concorde were presented with acertificate as a souvenir of their flight.presentationpresentation /�prez(ə)n |�teʃ(ə)n/noun showing, a display � The mostwidely acceptable presentation of flightfuel data is in a tabular form.presentlypresently /�prez(ə)ntli/ adverb 1.soon � I’ll be there presently. 2. USnow, at the present time � he’s pres-ently in France at the present time, heis in France � a number of methodsare presently in use a number of meth-ods are currently in usepresetpreset /�pri�|�set/ verb to set inadvance � Radios allow the user to pre-set a number of different frequencies.(NOTE: presetting – preset) � adjectiveset in advancepresspress /pres/ verb to push or exert pres-sure on � press to test/talk (PTT) button� Press the button.pressurepressure /�preʃə/ noun force applieduniformly over a surface, measured asforce per unit of area � fuel pressurepressure exerted by fuel as it is pumpedfrom the tanks to the engine � pressureswitch a switch which is activated whena preset pressure is attained � On someengines a fuel differential pressureswitch fitted to the fuel filter senses thepressure difference across the filter ele-ment. � absolute pressurepressure altimeterpressure altimeter /�preʃə ��lt|

�mi�tə/ noun a conventional altimeterwhich operates using atmospheric pres-surepressure altitudepressure altitude /�preʃə��ltitju�d/ noun the altitude indicatedwhen the altimeter is set to 1013.2 mil-libars � When using flight levels, thealtimeter should be set to 1013.2 mb togive the pressure altitude.

COMMENT: Pressure altitude is used indetermining density altitude, truealtitude and true airspeed.

pressure bulkheadpressure bulkhead /�preʃə�b�lkhed/ noun a partition inside theaircraft which separates pressurisedfrom non-pressurised areas

pressure gaugepressure gauge /�preʃə $ed"/noun an instrument for measuring pres-surepressure relaypressure relay /�preʃə �ri�le/ nouna component which transmits fluidpressure to a direct reading pressuregauge, or to a pressure transmitterwhich electrically indicates pressure onan instrument on the hydraulic panelpressurisationpressurisation /�preʃəra |

�zeʃ(ə)n/, pressurization noun the actof increasing the air pressure inside aspace, e.g. an aircraft cabin, so that itfeels normal for the occupants when theoutside air pressure decreasespressurisepressurise /�preʃəraz/, pressurizeverb to increase the pressure of � Whenair pressure is used to transfer fuel, itwill be necessary to pressurise the fueltanks.prevailprevail /pr|�vel/ verb to be most com-mon or frequent � Hot dry conditionsprevail in the Middle East in summer-time. � the prevailing wind is from thesouth-west the wind blows from thesouth west more often than from anyother directionpreventprevent /pr|�vent/ verb to stop fromhappening � Heated air provides suffi-cient heat in the outer skin to melt icealready formed and prevent any furtherice formation.previousprevious /�pri�viəs/ adjective comingbefore, earlier � the previous chapterthe chapter before the one being read orreferred to � previous reports earlierreportsprimarilyprimarily /pra|�mer(ə)li/ adverb mostoften, mainly � Dry chemical fire extin-guishers are primarily used for electri-cal fires.primaryprimary /�praməri/ adjective first ormost important � of primary impor-tance of greatest importance � primarycoil an induction coilprimary flight displayprimary flight display noun sameas primary flight instrumentsprimary flight instrumentsprimary flight instruments/�praməri �flat �nstrυmənts/ pluralnoun the six instruments displayed onthe instrument panel immediately infront of the pilot: airspeed indicator,attitude indicator, altimeter, turn coor-


179 product

dinator, heading indicator, and verticalspeed indicator � When practisinginstrument flying, the attitude indicatoris the most important of the primaryflight instruments.primary radar

primary radar /�praməri �redɑ�/noun a radar system which usesreflected radio signalsprime

prime /pram/ adjective first � primeimportance greatest importance � verbto pump fuel spray into the pistonengine inlet manifold to make startingfrom cold easier � During the summer,after the first flight of the day, it is notnormally necessary to prime the engine.prime number

prime number /�pram �n�mbə/noun a number, which, if there is to beno remainder, is only divisible by itselfand 1, e.g. 13, 17, 19, 23, 29primer

primer /�pramə/ noun 1. a protectivesubstance which is applied to a metal orwood surface before painting � Interiormetal finishing is done with dust shed-ding gloss-paint over a primer. 2. asmall hand-operated pump, operatedfrom the cockpit, to spray fuel into thepiston engine inlet manifold to makestarting from cold easierprincipalprincipal /�prnsp(ə)l/ adjectivemain � Four principal control modescan be selected on the EFIS (electronicflight instrument system) control panel.principleprinciple /�prnsp(ə)l/ noun a basictruth or law � Fire extinguishing isbased on the principle of removing oneof the three components necessary forfire to exist – fuel, oxygen and heat.(NOTE: Do not confuse with principal.)prior

prior /�praə/ adjective earlier, previ-ous � prior approval � prior permission� prior to before � prior to our depar-ture � prior to take-off before take-off

‘…the pilot remembered hearing the stallwarning immediately prior to impact’[Pilot]

priority

priority /pra|�ɒrti/ noun the order ofimportance or urgency � high priorityimportant or urgent in the circum-stances � low priority not important orurgent in the circumstancesPrivate Pilot’s Licence

Private Pilot’s Licence /�pravət�paləts �las(ə)ns/ noun the basic

licence for flying light aircraft. Abbre-viation PPLPRNAVPRNAV abbreviation precision areanavigationprobabilityprobability /�prɒbə|�blti/ noun like-lihood, the chance of occurrence � Theprobability of aquaplaning increases asthe depth of tyre tread decreases.probableprobable /�prɒbəb(ə)l/ adjectivelikely, most possible � Pilot error wasthe probable cause of the accident.probeprobe /prəυb/ noun a metal sensingdevice � Ice is allowed to accumulateon a probe which projects into the air-stream.proceduralprocedural /prə |�si�d"ərəl/ adjectivereferring to procedureprocedural approachprocedural approach /prə|

�si�d"ərəl ə |�prəυtʃ/ noun a specificapproach made often after procedureturns as part of timed, accurately flownflight pattern to prepare for a landing ata particular aerodrome � It is importantthat the integrity of an aid used to con-duct procedural approaches is high.procedureprocedure /prə |�si�d"ə/ noun 1. aseries of actions taken to achieve some-thing � an emergency procedure 2. theprocess by which aircraft are broughtinto position for an instrument approachand landingprocedure turnprocedure turn /prə |�si�d"ə t%�n/noun a turn made at 3° per second toalign the aircraft with the runwayprocessprocess /�prəυses/ noun a series ofactions or changes which achieve a par-ticular result � adiabatic process � com-bustion process � cooling processproduceproduce /prə|�dju�s/ verb 1. to create� Low altostratus clouds often producerain. 2. to make or to manufacture �

Most light aircraft are produced in theUnited States. 3. to show � The pilotmust produce her licence to the author-ities within two weeks.productproduct /�prɒd�kt/ noun 1. some-thing created or made by human or nat-ural methods � Carbon monoxide is aproduct of the combustion process. 2. anumber obtained by multiplying twoother numbers together � The amount ofpower produced in a purely resistive


production 180

circuit is a product of voltage and cur-rent (P = VI watts).productionproduction /prə |�d�kʃən/ noun 1.creation � The movement of air over theaerofoil is necessary for the productionof lift. 2. the process of manufacturingsomething � Production of aircraft inthe factory came to a stop in 1974. 3.the act of showing � An authorised per-son may require the production of a cer-tificate of airworthiness.profileprofile /�prəυfal/ noun 1. an outlineor shape of something, seen from a sideview � The de-icing panels are formedto the profiles of the wing and tail unitleading edges into which they are fitted.2. a short description � The handbookgives a short profile of the different air-craft types.prognosticprognostic /prɒ$ |�nɒstk/ adjectivereferring to foretelling or foreseeingevents such as the weatherprognostic chartprognostic chart /prɒ$ |�nɒstk�tʃɑ�t/ noun a chart which predicts theweather for a given area � Prognostic orforecast charts are prepared, by thecentral meteorological office of eachregion, normally for periods up to 24hours ahead. Also called forecastchartprogrammeprogramme /�prɒd"ekt/ noun theschedule of events to take place or pro-cedures to be followed � Every part ofthe aircraft must be designed to carrythe load imposed on it and in order todetermine such loads a programme ofstress analysis is always carried out.(NOTE: The word is also written pro-gram in US English.)progressprogress /�prəυ$res/ noun move-ment towards an end or aim � theprogress of an aircraft in flight � inprogress taking place � embarkationis in progress passengers are boardingthe aircraftprogressionprogression /prəυ |�$reʃ(ə)n/ noun acontinuous series or sequence � Theinstruments are checked in logical pro-gression from left to right.progressiveprogressive /prə |�$resv/ adjectivegradual, in stages � Throttle movementsshould be kept to a minimum and besmooth and progressive.

prohibitprohibit /prəυ |�hbt/ verb to disallowor forbid � Smoking is prohibited in toi-lets.projectproject noun /�prɒd"ekt/ a large-scale plan or scheme � a project to mod-ernise the airport � verb /prə |�d"ekt/ 1.to protrude or jut out � Ice is allowed toaccumulate on a probe which projectsinto the airstream. 2. to produce animage on a screen with a film or slideprojector � The instructor projected adiagram of the fuel system onto thescreen.projectionprojection /prə |�d"ekʃən/ noun theproduction of an image on a surfaceprolongprolong /prə|�lɒŋ/ verb to increase theduration or time, often unnecessarily �

to prolong the life of an engine � Pro-longed idling at low rpm (revolutionsper minute) could cause spark plugfouling.promulgatepromulgate /�prɒməl$et/ verb tomake known through official means �

The range promulgated for NDBs (non-directional radio beacons) in theUnited Kingdom is based on a daytimeprotection ratio between wanted andunwanted signals.proneprone /prəυn/ noun � prone to likelyto do something, or more than usuallyaffected by something � Wing leadingedges and engine intakes and propellersare prone to icing.pronouncedpronounced /prə |�naυnst/ adjectivenoticeable or marked � Turbulencecaused by convection is more pro-nounced over paved surfaces than overforest or grassy terrain.propagationpropagation /�prɒpə|�$eʃ(ə)n/ nountransmission � The speed of propaga-tion of radio waves is slower over landthan sea.propelpropel /prə |�pel/ verb to cause to move� Fronts are propelled by the windbehind them.propellerpropeller /prə|�pelə/ noun a rotatingshaft with blades which, together withthe engine, moves an aircraft throughthe airpropeller bladepropeller blade /prə |�pelə bled/noun one of the elements of a propellerwhich generate lift when the unit isturning


181 providepropeller pitchpropeller pitch /prə|�pelə ptʃ/ nounthe distance a propeller would advancein one rotation if there was no slippropeller tippropeller tip /prə|�pelə tp/ noun thepart of the blade of a propeller furthestfrom the central hubpropelling nozzlepropelling nozzle /prə |�pelŋ�nɒz(ə)l/ noun the extreme rear part ofthe jet engine where the jet exhaustenters the atmosphereproperlyproperly /�prɒpəli/ adverb correctly �When the chart is properly orientated, itis easier to compare distance betweenlandmarks. � The pinpoint is a very pos-itive means of establishing position, aslong as the feature is properly identi-fied.propertyproperty /�prɒpəti/ noun 1. a charac-teristic or quality � Mass is a basicproperty of matter. � One of the proper-ties of mercury is that it is liquid atroom temperature. 2. the things thatsomebody owns, possessions � per-sonal property things belonging to aparticular personpropjetpropjet /�prɒpd"et/ noun same as tur-bopropproportionproportion /prə |�pɔ�ʃ(ə)n/ noun 1.part of the whole compared withanother part � Only a small proportionof passengers absorb the pre-departuresafety information. 2. � in proportionto directly related to � The forcerequired to move the control column isin proportion to the force being exertedby the control surface.proportionalproportional /prə|�pɔ�ʃ(ə)n(ə)l/adjective 1. comparable 2. related �(directly) proportional directly related� The wind blows along contours withlow values on the left, and the speed isdirectly proportional to the contourgradient. � inversely proportional sothat as one thing increases and anotherdecreases by the same amount � Tem-perature is inversely proportional toaltitude. � The magnitude of the pres-sure gradient force is inversely propor-tional to the distance apart from the iso-bars.propulsionpropulsion /prə|�p�lʃən/ noun an actor instance of pushing or driving for-wards (NOTE: The verb is to propel.)

propulsivepropulsive /prə|�p�lsv/ adjectivepushing or driving � The propeller is ameans of converting engine power intoa propulsive force called thrust. (NOTE:The verb is to propel.)propulsive powerpropulsive power /prə |�p�lsv�paυə/ noun the power needed to pro-duce thrustprotectprotect /prə|�tekt/ verb to keep fromharm, injury or damage � Gloves areworn to protect the hands in the event ofa fire.protectionprotection /prə |�tekʃən/ noun the actof keeping something from harm, injuryor damage � fire protection action ormeasures taken to prevent fireprotectiveprotective /prə |�tektv/ adjectivereferring to something which keepssomething else from harm, injury ordamage � Busbars are insulated fromthe main structure and are normallyprovided with some form of protectivecovering.protrudeprotrude /prə|�tru�d/ verb to extendabove a surface � Prominent mountainsfrequently protrude above low-lyingcloud and mist.protrusionprotrusion /prə|�tru�"(ə)n/ nounsomething which protrudes or extendsabove a surface � When it has been nec-essary to physically remove a layer ofsnow, all protrusions and vents shouldbe examined for signs of damage.proveprove /pru�v/ verb 1. to show thatsomething is true � The pilot provedthat she was not at fault. 2. to be foundto be, to be discovered to be (NOTE:proving – proved – has proved or hasproven) � to prove useful to be discov-ered as useful by experience � drychemical extinguishers are used pri-marily for electrical fires and havealso proved effective on liquid fires itwas discovered that, although theseextinguishers were designed for electri-cal fires, they were good at putting outliquid fires such as petrol firesprovideprovide /prə|�vad/ verb to supply orto give � Radio altimeters provide acontinuous indication of height abovethe surface immediately below the air-craft up to a maximum of 5,000 feet. �

Flight crews are frequently provided


provision 182

with a full meteorological briefing. �

Each tank is provided with a shut offvalve. � When aquaplaning, a tyre is notcapable of providing directional controlor effective braking. � provided that oncondition that, if � The flight will takeoff on schedule provided that theweather improves.provisionprovision /prə|�v"(ə)n/ noun 1. pro-viding something, or what is provided �The provision of fresh air is importantfor passengers’ comfort. � Cateringcompanies are responsible for the pro-vision of food. � There is a generator forthe provision of emergency power. �

The oil tank has provision for filling anddraining. 2. a legal statement whichprovides for something such as particu-lar circumstancesproximityproximity /prɒk|�smti/ noun near-ness in space or time � The two aircraftwere in close proximity.psychological stresspsychological stress/�sakəlɒd"k(ə)l �stres/ noun a men-tally or emotionally upsetting conditionwhich affects one’s healthPTTPTT abbreviation press to test/talkpublicpublic /�p�blk/ noun people in gen-eral � adjective referring to the peoplein generalpublic address systempublic address system /�p�blk ə |

�dres �sstəm/ noun a microphone,amplifier and loudspeaker set up toallow one person to be heard by a groupof people � The captain made a publicaddress (PA) system announcementasking passengers to remain seated.Abbreviation PA systempublicationpublication /�p�bl|�keʃ(ə)n/ noun1. the act of making something public,publishing � the publication of the lat-est figures 2. a book, magazine, chart,etc., which has been published � Thebook is a Civil Aviation Authority publi-cation.public relationspublic relations /�p�blk r |

�leʃ(ə)nz/ noun the task of maintaininggood relations with the public. Publicrelations may also involve puttingacross a point of view or publicising aproduct. � The arrangements for theVIPs are being handled by the publicrelations department. Abbreviation PR

publish

publish /�p�blʃ/ verb to prepare andissue a book, magazine, chart, etc., andsell or distribute it to the public � Allknown air navigation obstructions inthe UK are published in the Air Pilot.pull out

pull out /�pυl �aυt/ verb to stop a divein an aircraft and return to level flightpullout

pullout /�pυlaυt/ noun a manoeuvrein which an aircraft changes from a diveto level flightpulse

pulse /p�ls/ noun a single vibration ofelectric currentpulse modulation

pulse modulation /�p�ls�mɒdjuleʃ(ə)n/ noun the use of aseries of short pulses, which are modi-fied by an input signal, to carry infor-mationpump

pump /p�mp/ noun a device withrotary or reciprocating action which isused to move fluids along pipes or forcompressing fluids � verb to move orcompress a fluid by means of a pump �

Fuel is pumped from the tanks to thecarburettor.

COMMENT: Most modern aircraft arefitted with hydraulic pumps driven fromthe engine. Other types of pumps maybe found, but these are usually used topower emergency systems. Pumpscan be driven directly from the enginegearbox, by an electric motor, or by air.

pure

pure /pjυə/ adjective not mixed withsomething else � Inner tubes for tyresare made of pure rubber. � Magnesiumdoes not possess sufficient strength inits pure state for structural uses. � purealuminium aluminium which has notbeen combined with any other metal tocreate an aluminium alloypurple airway

purple airway /�p%�p(ə)l �eəwe/noun an area of temporarily controlledairspace, established to provide specialprotection to Royal flights in fixed-wing aircraft, in which additional rulesfor air traffic apply at all times and in allweatherspurpose

purpose /�p%�pəs/ noun 1. function �

The purpose of the engine is to convertheat energy to mechanical energy. 2. ause � For practical purposes, anystraight line drawn on a Lambert’schart represents a great circle. � gen-


183 pyrotechnic

eral purpose for all-round or generalusepush-backpush-back /�pυʃ b�k/ noun the proc-ess of pushing a plane out from itsparked position using a special vehiclepushrodpushrod /�pυʃrɒd/ noun a steel oraluminium rod which moves the rockerarm � The camshaft operates the push-rod. (NOTE: The pushrod is part of thevalve mechanism.)pylonpylon /�palən/ noun 1. a structure onthe wing of an aircraft to support an

engine (NOTE: Most modern jet passen-ger transport aircraft have pylon-mounted engines.) 2. a tall metal struc-ture built to support electricity or tele-phone cables � Electricity pylons aredifficult to see from the air so pilots oflight aircraft should be particularlycareful to note their positions.pyrotechnic

pyrotechnic /�parə |�teknk/ adjec-tive of or relating to fireworks � pyro-technic lights lights created by rocketsor flares


QQ-code

Q-code /�kju� kəυd/ noun an interna-tional telegraph code which is now usedin RTF operationsQDM

QDM noun in the Q-code system, themagnetic bearing to a direction-findingstationQFE

QFE noun in the Q-code system, theatmospheric pressure at aerodromelevelQFI

QFI abbreviation qualified flyinginstructorQNE

QNE noun in the Q-code system, thealtimeter setting for flight level reading,1013.25 mbQNH

QNH noun in the Q-code system, theatmospheric pressure at mean sea levelQNH datum

QNH datum /�kju� en �etʃ �detəm/noun the barometric level from whichaltitude is measuredQTE

QTE noun in the Q-code system, thetrue bearing from a direction-findingstationquadrant

quadrant /�kwɒdrənt/ noun 1. adevice shaped like a quarter of a circle �gated quadrant a quadrant with adevice preventing a lever from beingmoved to an incorrect setting � Thethrottles, usually known as powerlevers, operate in a gated quadrant. 2. �compass quadrant the quarter part of acircle centred on a navigational aid

COMMENT: NE quadrant = 000° –089°; SE quadrant = 090° – 179°; SWquadrant = 180° – 269°; NW quadrant= 270° – 359°.

quadrantal

quadrantal /kwɒ|�dr�nt(ə)l/ adjec-tive referring to a quadrant or to a quar-ter of a circle � quadrantal error a

radio signal error caused by the metalstructure of the receiving aircraft �quadrantal height flight levels in eachof the compass quadrants designed toprovide safe separation for aircraftheading towards each otherqualified

qualified /�kwɒlfad/ adjective hav-ing gained a certificate after havingcompleted a specialised course of studyqualified flying instructor

qualified flying instructor/�kwɒlfad �flaŋ n |�str�ktə/ noun apilot with an instructor’s rating. Abbre-viation QFIqualify

qualify /�kwɒlfa/ verb 1. to add res-ervations or modify an earlier statementto make it less absolute � Fire in thewing may cause the captain to qualifythe evacuation command, informingcabin crew of these conditions andallowing them to adjust the evacuationplan accordingly. 2. to study for andobtain a diploma which allows to do aparticular type of work � He qualifiedas an engineer in 1996.quality

quality /�kwɒlti/ noun the amount ofexcellence of something � Satisfactoryignition depends on the quality of thefuel.quantity

quantity /�kwɒntti/ noun the size,extent, weight, amount or number ofsomething � A small quantity of illegaldrug was found in the passenger’s bag.quarter

quarter /�kwɔ�tə/ noun one fourth ofsomething � The fuel tank is only aquarter full.QUJ

QUJ noun in the Q-code system, thetrue track to reach a destination


Rradar

radar /�redɑ�/ noun a method ofdetecting distant objects and establish-ing their position, velocity, or othercharacteristics by analysis of very highfrequency radio waves reflected fromtheir surfacesradar advisory service

radar advisory service /�redɑ� əd |

�vaz(ə)ri �s%�vs/ noun an air trafficradar service which gives pilots adviceon actions necessary to ensure that theyremain at a standard distance from otheraircraft that are also receiving the serv-ice. Abbreviation RASradar beam

radar beam /�redɑ� bi�m/ noun ashaft of radar waves directed towards adistant pointradar information service

radar information service/�redɑ� �nfə |�meʃ(ə)n �s%�vs/ an airtraffic radar service which gives pilotsdetails of the positions, distances andlevels of other aircraft to enable them todecide on any avoiding action whichmay be appropriate. Abbreviation RIS(NOTE: An RIS is often provided when itis not possible or practical to provide anRAS.)radar screen

radar screen /�redɑ� skri�n/ noun acathode ray tube screen on which radarinformation is displayedradar vectoring

radar vectoring /�redɑ� �vektərŋ/noun the provision of navigationalguidance to aircraft in the form of spe-cific headings, based on the use of radarradial

radial /�rediəl/ adjective referring tolines of radius having a common centre� radial engine engine in which the pis-tons are arranged like the spokes of awheel � noun a line of radio bearingfrom a VOR beacon � To get to a facility

you must track the reciprocal of theVOR radial.radiateradiate /�rediet/ verb to send outrays or waves � The Earth radiates lowintensity infrared waves. � Short burstsof energy are radiated from an antenna.radiationradiation /�redi|�eʃ(ə)n/ noun the actor process of sending out rays or waves� terrestrial radiation radiation fromthe Earthradiation fogradiation fog /�redi|�eʃ(ə)n �fɒ$/noun fog caused by the cooling of theEarth to below the dew point, combinedwith saturation and condensation and alight mixing wind � Radiation fog can-not form over the sea.radiatorradiator /�redietə/ noun a liquid-to-air heat exchanger that transfers engineheat to the outside air � Anti-icing addi-tives are used in radiator coolants. �

coolantradioradio /�rediəυ/ noun wireless trans-mission through space of electromag-netic waves in the approximate fre-quency range from 10 kHz to 300,000MHz � radio waves electromagneticradiation waves � The atmosphereabsorbs radio waves.radio aidradio aid /�rediəυ ed/ noun a navi-gation aid utilising radio wavesradio altimeterradio altimeter /�rediəυ ��lt|

�mi�tə/ noun a device for measuring theheight of the aircraft above the Earthusing reflected radio wavesradio horizonradio horizon /�rediəυ hə|�raz(ə)n/noun a line along which direct raysfrom a radio frequency transmitterbecome tangential to the Earth’s surfaceradio magnetic indicatorradio magnetic indicator/�rediəυ m�$ |�netk �ndketə/ noun


radiotelephony 186

a cockpit navigation instrument whichcombines a bearing indicator and aheading indicator and can be used withADF or VOR. Abbreviation RMIradiotelephonyradiotelephony /�rediəυtə|�lefəni/noun the transmission of speech byradio � Correct use of R/T phraseologyavoids ambiguity. Abbreviation R/Tradiusradius /�rediəs/ noun � the radius ofa circle a line drawn from a point on thecircumference of a circle to the centrepoint (NOTE: The plural form is radii./�redia/)radomeradome /�redəυm/ noun a dome thatprotects a radar antenna, made frommaterials that do not interfere with thetransmission and reception of radiowavesRAFRAF abbreviation Royal Air Forceraftraft /rɑ�ft/ noun a flat-bottomed inflat-able rubber craft for floating on waterrailway linerailway line /�relwe lan/ noun arailway track or train track � A railwayline is a useful landmark.rainrain /ren/ noun precipitation or waterwhich falls from clouds in small drops �Rain is falling heavily. � Rain andweather present fewer problems forarea radar compared to the other types.� verb to fall as drops of water fromclouds � It is raining. � I don’t think itwill rain.rainstormrainstorm /�renstɔ�m/ noun heavyrain accompanied by wind � In heavyrainstorm, the windscreen wipers maynot be able to cope.raiseraise /rez/ verb 1. to lift � raise thelanding gear retract the undercarriage2. to increase � to raise the temperature� to raise the pressure 3. to cause prob-lems � Fuel vaporisation can raiseproblems when starting the engine.(NOTE: Do not confuse with the verb torise. Grammatically, the verb raisetakes an object whereas the verb risedoes not: temperature rises; The sun’srays raise the temperature of the sur-face.)rakerake /rek/ noun the angle between awing or propeller blade of an aircraftand a perpendicular or line of symmetryramram /r�m/ noun an increase in airpressure caused by the forward speed of

the aircraft � Due to ram effect from air-craft forward speed, extra air is takeninto the engine.ram airram air /�r�m eə/ noun airflow cre-ated by the movement of the aircraftwhich is used to cool, ventilate or driveturbines � Oil cooling is often achievedby using ram air or fuel.ramjetramjet /�r�md"et/ noun a type of jetengine in which fuel is burned in a ductwith air compressed by the forwardmotion of the aircraftrampramp /r�mp/ noun 1. an inclined trackfor loading and unloading � The heightof the cabin floor to the ground on largejet transports means that injuries canoccur by exiting through the doorswhen steps or ramps are not available.2. US same as apronrange

range /rend"/ noun 1. the amount orextent of variation � range of frequen-cies � range of temperatures 2. a row orchain of mountains or hills � the RockyMountain range � Valley winds requireat least a reasonable pressure gradient,preferably along a range of hills whichwill produce a wind at right angles tothe hills. 3. the maximum distance anaircraft can fly on a given amount offuel � Cruise level is selected to give thegreatest fuel economy, i.e. the greatestrange for least fuel. 4. the maximumeffective distance of operation � Preci-sion approach radar (PAR) is subject toweather interference and has a limitedrange. � verb � to range from … to …to vary from … to … � Temperaturesrange from 0°C (Celsius) at night to40°C (Celsius) at midday.rapidrapid /�r�pd/ adjective fast, withgreat speed � Hoar frost is a light crys-talline deposit which can form on theaircraft as a result of rapid descent fromcold altitudes into warm moist air. �rapid changes fast changesrapidityrapidity /rə |�pdti/ noun great speed �Spontaneous combustion occurs withsuch rapidity that there is an audibleexplosion.rapidlyrapidly /�r�pdli/ adverb with greatspeed, quickly � Rime ice is formedwhen individual droplets of water freezerapidly on striking the aircraft surface.


187 readingrare

rare /reə/ adjective uncommon, notoften occurring � Smog or smoke fog isnow rare because of pollution controls.RAS

RAS abbreviation 1. radar advisoryservice 2. rectified air speedrate

rate /ret/ noun a quantity measured inrelation to another measured quantity �rate of climb speed of ascent measuredin feet per minute � rate of descentspeed of descent measured in feet perminute � flow rate the amount of move-ment of a fluid through a system in agiven time, e.g. gallons per minuterather

rather /�rɑ�ðə/ adverb 1. to someextent, somewhat � rather coldweather weather which is quite cold,but not very cold 2. � rather thaninstead of, preferably � Air tends to flowaround hills rather than rise over them.rating

rating /�retŋ/ noun 1. an authorisa-tion on a licence, and forming part ofthe licence, giving special conditions orprivileges 2. a classification accordingto a scaleratio

ratio /�reʃiəυ/ noun a relationshipbetween two quantities expressed as thequotient of one divided by the other �

The air/fuel ratio is 15:1. � Chart scaleis the ratio of the chart distance toEarth distance. (NOTE: The ratio of 7 to4 is written 7:4 or 7/4.)ray

ray /re/ noun a thin or narrow beam oflight or other radiant energy � cathoderay � The Earth is heated by the rays ofthe sun. � X-rayRBI

RBI abbreviation relative bearing indi-catorRCC

RCC abbreviation rescue co-ordinationcentreRCL

RCL abbreviation runway centrelinere-

re- /ri�/ prefix again � reassemble �

rewrite (NOTE: Not all verbs beginningwith re- have the meaning ‘again’, e.g.remember.)reach

reach /ri�tʃ/ verb 1. to arrive at a place� The aircraft reached its destination ontime. 2. to get to a particular level � Up-currents in thunderstorms can reach3,000 feet per minute. � Temperaturescan reach 49°C (Celsius) in summer-time in the Gulf region. 3. to extend �

The tops of thunderstorm clouds canreach through the tropopause.react

react /ri|��kt/ verb 1. to act in responseto an action � Because the rotors andstators of a compressor are of aerofoilshape, the airflow reacts in a similarway to the airflow over a wing. 2. to door to say something in response towords or to an event � The cabin crewreacted swiftly when the fire broke out.3. � to react with something to changechemical composition because ofanother substance � The electrolyte inthe cells of a lead-acid battery reactschemically with the plates.reactance

reactance /ri|��ktəns/ noun a com-ponent of impedance in an alternatingcurrent circuit � Reactance is a form ofresistance which varies as the fre-quency changes.reaction

reaction /ri|��kʃən/ noun a responseto an action or stimulus � For everyaction there is an equal and oppositereaction. � Passenger reaction may beslower than usual in an emergency situ-ation. � Quick reactions are needed inan emergency.reaction thrust principle

reaction thrust principle /ri|

��kʃən �θr�st �prnsp(ə)l/ the processby which exhaust gases coming of theback of an object cause a reaction forceto act on the object and push it forwardsreadback

readback /�ri�db�k/ noun the actionof repeating an ATC message to thecontroller to enable him or her to checkthat it was correctly receivedreadily

readily /�redli/ adverb 1. promptly,immediately � Fire extinguishers mustbe readily available for use. � Ice meltsvery readily at 0°C (Celsius). 2. � it canreadily be seen it can be easily under-stood � It can readily be seen from thepreceding paragraph that density andpressure are linked.reading

reading /�ri�dŋ/ noun 1. informationindicated by an instrument or gauge �altimeter reading the altitude indi-cated by the altimeter � barometerreading the barometric pressure indi-cated by the barometer 2. � map read-ing the act of interpreting informationon a map


readout 188readout

readout /�ri�daυt/ noun a display orpresentation of data from calculationsor storage � The rotating beam cloudbase recorder/indicator operates con-tinuously, day and night and producesan automatic readout of cloud baseheight.rear

rear /rə/ noun the aft part, the part fur-thest from the front � the rear of the air-craft � adjective at the back, or referringto the back � The rear part of the air-craft is called the aft section.rearward

rearward /�rəwəd/ adjective towardsthe aft or the rear � The expanding gastravels in a rearward direction.reason

reason /�ri�z(ə)n/ noun the basis ormotive for an action � A rough surfaceis more susceptible to fatigue crackingthan a smooth one and for this reasonhighly stressed members are often pol-ished.reasonable

reasonable /�ri�z(ə)nəb(ə)l/ adjec-tive 1. acceptable or fair � a reasonablesum of money a sum of money which isnot too high or which is acceptable 2.within the boundaries of common sense� It would be reasonable to expect thatradio frequencies would travel throughthe air in straight lines as a direct wave,but they bend, or refract.receive

receive /r|�si�v/ verb to get, to obtain� The sides of the hills and mountainswhich face the sun receive more intenseradiation than flat surfaces because ofthe angle of exposure to the sun.receiver

receiver /r|�si�və/ noun a device thatreceives incoming radio signals andconverts them to sound or light � Thetransponder in the aircraft consists of atransmitter and a receiver.recent

recent /�ri�s(ə)nt/ adjective referringto a time immediately before thepresent � Recent engine designs includevariable angle stator blades. � A morerecent development is the barographwhich utilises the electrical output ofthe digital display barometer. � recentweather significant weather observedin the period since the previous obser-vation, but not nowreception

reception /r |�sepʃən/ noun an act orinstance of receiving radio signals �

The antenna is highly directive in trans-mission and reception.reciprocalreciprocal /r |�sprək(ə)l/ adjective �reciprocal heading an opposite head-ing, 180° from a given heading � Thereciprocal heading of 090° is 270°. �

noun the exactly opposite direction � Awave transmitted vertically returns toEarth on its reciprocal.reciprocatingreciprocating /r |�sprəketŋ/adjective moving backwards and for-wards or up and downrecogniserecognise /�rekə$naz/, recognizeverb to identify, or to know to be some-thing that has been seen, heard, etc.before � It may be difficult to recognisea particular stretch of coastline simplyby its appearance.recognitionrecognition /�rekə$ |�nʃ(ə)n/ nounthe process of seeing or hearing some-thing or somebody and knowing what itis or who he or she is � Hydraulic fluidsare coloured for recognition purposes.recommendrecommend /�rekə |�mend/ verb tosay that something is worthy, desirableor suitable � Dry chemical extinguish-ers are recommended for use on aircraftbrake fires. � Aircraft should be oper-ated to the manufacturers recom-mended limits.recordrecord noun /�rekɔ�d/ 1. a writtenaccount of facts and information forfuture reference 2. a set of electroni-cally stored data � verb /r|�kɔ�d/ 1. towrite down something such as informa-tion or data � Measure track angles anddistances and record them in a log. 2. tocapture and store electronically �

Details of wind speed, direction, visibil-ity and cloud cover are recorded onto acassette.recorderrecorder /r|�kɔ�də/ noun a device forcapturing sound onto cassette or mag-netic tape � cockpit voice recorderrecordingrecording /r|�kɔ�dŋ/ noun the act ofwriting or of picking up and storinginformation � An anemograph is aninstrument which maintains a continu-ous recording of wind direction andspeed on a graph.recoverrecover /r|�k�və/ verb 1. to return toan earlier, normal condition or attitude� recover from a stall to return the air-


189 refer

craft to straight and level flight 2. to res-cue and remove from a particular area,often the sea � Emergency servicesrecovered two bodies from the wreckageof the helicopter.recovery

recovery /r |�k�v(ə)ri/ noun 1. areturn to an earlier, normal condition orattitude � recovery from unusual atti-tudes a flight exercise requiring the stu-dent pilot to return the aircraft to its pre-vious, normal, that is, straight and levelattitude, after it has been in an unusualattitude 2. rescue and removal from aparticular area � The recovery of survi-vors from the sea was carried out byhelicopters.rectangle

rectangle /�rekt�ŋ$əl/ noun a 4-sided plane figure with 4 right angles,and with opposite sides of equal length� The colour identification of refuellingequipment for AVGAS is: blue rectan-gle, red decal with AVGAS 100LL inwhite letters.rectangular

rectangular /rek|�t�ŋ$jυlə/ adjec-tive referring to something with theshape of a rectangle � a rectangularwing panelrectification

rectification /�rektf |�keʃ(ə)n/noun the process of changing an alter-nating current into direct current � Partof the generator alternating current(AC) is passed through a rectificationcircuit.rectified airspeed

rectified airspeed /�rektfad �eə |

�spi�d/ noun indicated airspeed cor-rected for instrument error and pressureerror � When rectified airspeed (RAS) iscorrected for density error the resultantis known as the true airspeed.rectifier

rectifier /�rektfaə/ noun an elec-tronic circuit that converts an alternat-ing current supply into a direct currentsupply � The ignition unit receives analternating current which is passedthrough a transformer and rectifier.rectify

rectify /�rektfa/ verb 1. to changealternating current into direct current �

Alternating current output is rectifiedand regulated externally and returnedas direct current to the stator fieldwinding. 2. to correct � to rectify a mis-take to put right a mistake

redeyeredeye /�reda/ noun a late night orovernight airline servicereducereduce /r |�dju�s/ verb to decrease, tomake less. Opposite increase � reducealtitude to descend � reduce tempera-ture to make coolerreduced separationreduced separation /r|�dju�st�sepə|�reʃ(ə)n/ noun a revised mini-mum separation which is smaller thanthe previous minimum separationreductionreduction /r|�d�kʃən/ noun adecrease � reduction in temperature,pressure, speedreduction gearreduction gear /r |�d�kʃən �$ə/noun gears in an engine which allow thepropeller to turn at a slower speed thanthe engineredundancyredundancy /r|�d�ndənsi/ noun theduplication of component parts of a sys-tem to enable the system to functioneven if one component fails � With sys-tem redundancy, a single failure withina system will have little effect on the air-craft’s performance during theapproach and landing operation.redundantredundant /r|�d�ndənt/ adjectivereferring to a system which providesextra component parts to enable the sys-tem to function even if one componentfails � Redundant structure design iscomposed of a large number of mem-bers, all of which share a load, so that ifone of the members is lost, the load car-ried by the member is divided betweenall the others in such a way that thetotal load-carrying ability is reducedonly slightly.reduxredux /�red�ks/ noun a method of fix-ing components together using adhe-sives and gluesre-enterre-enter /�ri� �entə/ verb to enteragain � For engine checks the aircraftshould be headed into wind to preventhot exhaust gases re-entering theengine.referrefer /r|�f%�/ verb 1. to describe or givea name to � The term wind is used torefer to the horizontal motion of air. 2.to direct someone to a source of help orinformation (NOTE: referring –referred) � refer to chapter 10 formore details look at or read chapter 10for more information


reference 190referencereference /�ref(ə)rəns/ noun some-thing used as a basis for further calcula-tion or investigation � visual referenceanything seen and used as a guide tosomething else � Use the large buildingas a visual reference for the turn ontofinal approach. � reference book abook in which you can look for infor-mation, e.g. a dictionary � by referenceto by looking at and comparingreference datumreference datum /�ref(ə)rəns�detəm/ noun a line fixed by thedesigner from which measurements aremade when checking or adjusting wingangles, etc.reference pointreference point /�ref(ə)rəns pɔnt/noun a fixed datum near the centre ofthe airfield landing areareference signalreference signal /�ref(ə)rəns�s$n(ə)l/ noun a signal against whichtelemetry data signals are comparedrefinementrefinement /r|�fanmənt/ noun animprovement � An internal lockingdevice is one of the numerous refine-ments to the simple actuator.reflectreflect /r |�flekt/ verb to throw backsomething such as radio waves or light� Snow surfaces reflect up to 90% ofradiation while rock, sand and concretereflect only 10–20%.reflectionreflection /r |�flekʃən/ noun the proc-ess of throwing back of something suchas radio waves or light � Glare causedby reflection of sunlight from the top ofa layer of fog or haze can seriouslyreduce the air-to-ground visibility.reflectivereflective /r |�flektv/ adjective ableto throw back something such as radiowaves or light � Reflective power meansthat at low angles of elevation of thesun, water reflects a great amount ofsolar radiation thus slowing down therise in sea surface temperatures.reflectorreflector /r |�flektə/ noun a devicewhich throws back something such aslight � The shape of a water dropletmakes it a good reflector, so water in theatmosphere absorbs and scatters radiowaves.refractrefract /r|�fr�kt/ verb to cause awave, such as light or sound, to changedirection or turn as it passes from onemedium into another of different den-

sity � A sky wave starts life as a directwave and, on reaching the ionosphere,the direct wave is refracted and returnsto the Earth’s surface.refractionrefraction /r |�fr�kʃən/ noun thechange in direction or turning of awave, such as light or sound, as it passesfrom one medium into another of differ-ent densityrefrigerantrefrigerant /r |�frd"ərənt/ noun asubstance to provide cooling either asthe working substance of a refrigeratoror by direct absorption of heat � Heatedair from the main air supply systempasses through the evaporator matrixand by induction releases heat into theliquid refrigerant.refuel

refuel /ri�|�fju�əl/, re-fuel verb to fillwith fuel again � Fire risk is alwayspresent when you defuel and refuel.regain

regain /r|�$en/ verb to obtain againor to acquire again � The omni-bearingselector/course deviation indicator is ademand instrument which indicateswhich way to turn to regain the requiredbearing.regardregard /r|�$ɑ�d/ noun a particularpoint or aspect � in this regard con-cerning this or with reference to this �with regard to concerning or with ref-erence to � With regard to the turbo-propeller engine, changes in propellerspeed and pitch have to be taken intoaccount. � verb to look upon or con-sider in a particular way � Thoughtfulconcern for others is regarded as anessential component of good airman-ship.regardless

regardless /r|�$ɑ�dləs/ prepositionin spite of, despite, with no thought of �with fly-by-wire technology, the air-craft’s stalling angle of attack cannotbe exceeded regardless of controlstick input the stalling angle of attackcannot be exceeded, despite or no mat-ter what the pilot does with the flyingcontrolsregionregion /�ri�d"ən/ noun 1. an area, usu-ally a large geographical area � Thetroposphere is deepest in equatorialregions and shallowest near the poles.2. � in the region of about or approxi-mately � The burning temperature of


191 relative bearing

the fuel is in the region of 2,000°C (Cel-sius).register

register /�red"stə/ noun an officiallist or record � The student’s name wasnot on the register. � verb 1. to record orto indicate on an instrument � Duringground running checks, if oil pressuredoes not register within a few seconds,the engine should be stopped and thecause investigated. � Electrically oper-ated pressure gauges register main andemergency system pressure. 2. to enterdetails on an official list � to register anaircraftregistration

registration /�red" |�streʃ(ə)n/noun the entry of civil aircraft intorecords of national certification author-ity with details of letter and numbercode displayed on aircraft � certificateof registration a document issued asproof of registrationregular

regular /�re$jυlə/ adjective 1. occur-ring at fixed time intervals � a regularflight � regular inspections inspectionstaking place at equal intervals of time 2.ordinary or standard � part of the regu-lar menuregulate

regulate /�re$jυlet/ verb to control,to adjust to a specific requirement �

Controllable cowl flaps regulate theamount of air flowing across the cylin-ders.regulation

regulation /�re$jυ |�leʃ(ə)n/ noun anact or instance of controlling or adjust-ing to a specific requirement � Regula-tion of cabin temperature is controlledby the manual setting of a mechanicallycontrolled switch.regulations

regulations /�re$jυ |�leʃ(ə)nz/ pluralnoun rules or lawsregulator

regulator /�re$jυletə/ noun a deviceused to control the flow of fluids orelectric current � voltage regulator adevice to control the level of voltageReid vapour pressure test

Reid vapour pressure test /�ri�d�vepə �preʃə test/ noun a test to deter-mine the pressure required above a liq-uid to hold the vapours in the liquid at agiven temperaturereinforce

reinforce /�ri�n |�fɔ�s/ verb to makestronger or to strengthen � Typical skinmaterials used in aircraft are made

from epoxy resins which are reinforcedwith glass, carbon or Kevlar fibres.reinforced

reinforced /�ri�n |�fɔ�st/ adjectivemade stronger or strengthenedreinforced plastics

reinforced plastics /�ri�nfɔ�st�pl�stks/ plural noun plastic materialsused with glass fibres to repair sometypes of aircraft structurereinforcement

reinforcement /�ri�n |�fɔ�smənt/noun the act of strengthening, or amaterial or structure used to strengthensomething � There is reinforcementaround each opening in the pressurecabin, such as the cabin door, escapehatch and windows.relate

relate /r|�let/ verb 1. to make a con-nection or link, to associate � Orientat-ing the chart relates the direction ofland features to their representation onthe chart and aids recognition. 2. � torelate to to concern or to be about �

Kepler derived the laws which relate tothe motion of planets in their orbits.relation

relation /r |�leʃ(ə)n/ noun 1. a naturalor logical association between things �

the relation between thrust and drag �this bears no relation to that this is notconnected with that in any way 2. � inrelation to with reference to � Therange at which objects can be recog-nised is affected by the direction ofviewing in relation to the position of thesun or the moon. � The VOR station onthe ground does the calculation and,depending on where the aircraft is inrelation to the VOR station, it willreceive signals which define the bearingof the aircraft from the VOR.relationship

relationship /r|�leʃ(ə)nʃp/ noun anatural or logical association betweenthings � There is a close relationshipbetween altitude and pressure.relative

relative /�relətv/ adjective � relativeto compared to, with reference to �

Ground-speed is the speed of the air-craft relative to the ground.relative airflow

relative airflow /�relətv �eəfləυ/noun airflow over an aerofoil, oftenrelated to the chord line of the aerofoil.Also called relative windrelative bearing

relative bearing /�relətv �beərŋ/noun the bearing of a radio station or


relative density 192

object with reference to the aircraft’sheadingrelative densityrelative density /�relətv �densti/noun the ratio of density of a liquid withreference to water, or of a gas with ref-erence to airrelative humidityrelative humidity /�relətv hju�|

�mdti/ noun the ratio between theamount of water vapour in the air andthe amount which would be present ifthe air was saturated, at the same tem-perature and the same pressurerelative windrelative wind /�relətv �wnd/ nounsame as relative airflowrelayrelay /�ri�le/ noun a device whichresponds to a small current or voltagechange by activating switches or otherdevices in an electric circuit � Thermo-couple detectors operate a sensitiverelay or electronic circuit when a prede-termined temperature is exceeded. �

verb to pass an ATC message to an air-craft via another aircraft that is on thesame frequency and within radio range(NOTE: Messages may have to berelayed when atmospheric conditionsmake a direct transmission impossible)releaserelease /r|�li�s/ noun the act of freeingsomething from something that holds it� Air rising and cooling often reachesits dew point temperature, becomes sat-urated and any further cooling resultsin condensation and the consequentrelease of latent heat. � verb to freefrom something that holds it � Push thebutton to release the lever. � release thebrakes let the brakes off � to releasethe pressure to allow pressure toreducerelevantrelevant /�reləv(ə)nt/ adjective hav-ing a connection with the matter in hand� High charts show only informationrelevant to high altitude flights andmany beacons and aids which are pro-vided for low operations are omitted tokeep the chart clear. � relevant infor-mation useful information which isrelated to the matter in questionreliabilityreliability /r |�laə |�blti/ noundependability, trustworthiness � Thegas turbine is a very simple engine withfew moving parts, giving it high relia-bility with less maintenance.

‘…where a State introduces drug testing,high standards of medical reliability mustbe maintained’ [INTER PILOT]

reliablereliable /r |�laəb(ə)l/ adjectivedependable, trustworthy � The gas tur-bine is a very simple and reliableengine.reliefrelief /r |�li�f/ noun 1. variations in ele-vation of the surface of the earth �

Relief is usually represented on aero-nautical charts by contours, gradienttints or hill shading. 2. a lessening ofpressurerelief valverelief valve /r |�li�f v�lv/ noun avalve which opens at maximum safepressure and closes again upon return tonormal operating conditionsrelieverelieve /r|�li�v/ verb to cause a lessen-ing in, or to remove, excess pressure ortension � Safety valves relieve excesscabin pressure. � A trim tab on the ele-vator relieves the forward and aft forceson the control stick or yoke.relightrelight /ri�|�lat/ verb to ignite again �

The ability of the engine to relight willvary according to the altitude and theforward speed of the aircraft.relyrely /r|�la/ verb to be dependent on �

Pressure carburettors do not rely onventuri suction to discharge fuel intothe airstream.remainremain /r|�men/ verb to stay, to con-tinue to be � During the evacuation,crew must remain at their assigned sta-tions and redirect passengers. � Thefuel/air ratio does not remain constant,but, as the speed increases, the mixturegets richer. � The audible fire warningsmay be cancelled but the red warninglight will remain on.remainderremainder /r|�mendə/ noun 1.something left after excluding otherparts, the rest � The auxiliary powerunit is usually found in the tail section,separated from the remainder of thefuselage by a firewall. 2. the number leftover when one number is divided byanotherremoteremote /r |�məυt/ adjective 1. faraway, and not near anything else � aremote area � When the destination is aremote island, the calculation of thepoint of no return (PNR) becomes


193 representation

essential. 2. operated or controlled froma distance � remote cabin pressure con-trollers 3. � a remote chance a smallbut unlikely possibilityremoval

removal /r |�mu�v(ə)l/ noun the act oftaking something away, or of movingsomething from the position it occupies� The repair to the aircraft required theremoval of the engine.remove

remove /r |�mu�v/ verb to take some-thing away or move it from the positionit occupies � Filters are fitted in lines ina hydraulic system, in order to removeforeign particles from the fluid. � Theengine will have to be removed forrepair.render

render /�rendə/ verb 1. to cause tobecome � The failure of any componentin the fire detection system will renderthe system inoperative. � Tropical airmoving northwards is subjected to sur-face cooling and rendered increasinglystable in its lower layers. 2. to give � torender assistance to provide help �

Only when all possible assistance hasbeen rendered inside the cabin willcrew themselves evacuate.repair

repair /r |�peə/ noun an actiondesigned to return something to goodcondition after damage � The repair tothe nosewheel took three hours. � verbto mend or otherwise return to goodcondition after damage � After thewheels-up landing, the flaps had to berepaired.

‘Mr Pike elected to await repairs insteadof taking up the offer of alternativeflights, and found himself the onlypassenger aboard the Jumbo as it flewback to Heathrow four hours late’ [Pilot]

repeat

repeat /r|�pi�t/ verb 1. to do again �

The first officer repeated the transmis-sion. � The trainee had to repeat hernavigation examination. 2. to occuragain � Metal fatigue is induced byrepeated stress cycling. 3. to say again �Could you repeat that please? I didn’thear. � The message was repeated a fewminutes later.repel

repel /r |�pel/ verb to push away by aforce � Like poles (i.e., north and north,or south and south) of a magnet repel

each other. (NOTE: repelling –repelled)repellentrepellent /r|�pelənt/ noun a sub-stance used to resist the effect of some-thing � Rain repellent is sprayed ontothe windscreen and spread by the wip-ers.replacereplace /r |�ples/ verb to take theplace or to fill the place of � As warmair rises, cold air moves in to replace it.� The term Greenwich Mean Time(GMT) is being replaced by the termCoordinated Universal Time (UTC).replacementreplacement /r|�plesmənt/ noun 1.the act of replacing something withsomething else � The replacement ofmoist air by dry air is the only sure wayof dispersing advection fog. 2. some-thing or somebody that replaces some-thing or somebody else � She was hiredas a replacement for a manager whohad recently retired.replyreply /r|�pla/ noun an answer orresponse � Secondary surveillanceinterrogation is made on 1030 MHz(megahertz) and the reply on 1090 MHz(megahertz). � verb to answer, torespond � He replied to the letter.(NOTE: replying – replied)reportreport /r|�pɔ�t/ noun an officialaccount of an occurrence � incidentreport � weather report � verb to writeor tell information in an official manner� The observer measures this distancein a number of directions and reportsthe minimum value as the meteorologi-cal visibility. � An accident must bereported.reporting pointreporting point /r|�pɔ�tŋ pɔnt/noun a specified geographical locationon an aircraft’s route at which the crewmust report to air traffic controlrepresentrepresent /�repr|�zent/ verb to indi-cate or to show, using signs or symbols� On a Mercator projection, meridiansare represented as parallel straightlines.representationrepresentation /�reprzen|�teʃ(ə)n/noun a way of showing something,using signs or symbols � The synopticchart provides a representation of theweather over a large area at a particu-lar time.


representative 194representativerepresentative /�repr |�zentətv/adjective � representative of which is atypical example of what all others arelike � Surface air temperatures aretaken in such a way as to be representa-tive of the air temperature near the sur-face yet unaffected by the direct surfaceheating or cooling effects. � noun a per-son who acts or speaks for another per-son or for an organisation such as acompanyrequestrequest /r |�kwest/ noun a politedemand, or what is asked for � ATC (airtraffic control) received a request fromthe pilot for departure clearance. � onrequest when asked for � A personalflying log book must be retained forproduction on request by an authorisedperson. � verb to ask for something �

The pilot requested vectors to enablehim to locate the airfield.requirerequire /r |�kwaə/ verb 1. to need �

Dynamic seals require lubrication toremain effective. 2. to impose an obliga-tion, to compel by law � Transportoperations over water require the car-riage of life rafts, life jackets, survivalbeacons and pyrotechnics.requirementrequirement /r |�kwaəmənt/ noun1. what is necessary � Planning for anin-flight emergency is a standardrequirement of pre-departure prepara-tion. 2. � legal requirement an obliga-tion by law 3. something which isdemanded or required � The airframehad to be built to very specific require-ments.re-registerre-register /�ri� �red"stə/ verb toregister again � The aircraft had to bere-registered because of an administra-tive error.rescuerescue /�reskju�/ noun the act of free-ing from danger � Early rescue dependson the rapid location of survivors. �

verb to free from danger � Passengerswere rescued from the burning aircraft.reservereserve /r|�z%�v/ noun somethingkept back for possible future use � verbto keep something such as a seat forsomebody � Seats 23A and 23B arereserved for Mr and Mrs Smith.reserve fuelreserve fuel /r |�z%�v �fju�əl/ nounfuel used only in a situation when the

aircraft has to be in the air for a longertime than expected, as because of a go-around or diversionreservoirreservoir /�rezəvwɑ�/ noun a con-tainer for holding a store of fluid � Areservoir provides both storage spacefor the system fluid, and sufficient airspace to allow for any variations in thevolume of the fluid in the system.resetreset /ri� |�set/ verb to set again �

Instruments which need resetting inflight must be accessible to the crew.(NOTE: resetting – reset)resettableresettable /ri�|�setəb(ə)l/ adjectivepossible to reset � Circuit breakers areresettable protective devices.residualresidual /r |�zdjuəl/ adjective refer-ring to the residue of somethingresidueresidue /�rezdju�/ noun the remain-der of something after the removal ofthe main part � The leaking oil left asticky residue on the ground.resinresin /�rezn/ noun materials whichare used with fillers and other compo-nents to form plastics, e.g. polyesters,epoxies and silicones � To make a com-posite it is necessary to combine thereinforcing glass fibres with some formof special glue or resin.resistresist /r|�zst/ verb to fight off theeffects of something � A tube resistsbending in any direction but beams aredesigned usually to resist bending inone or two directions only. � In orderfor an aeroplane to fly, lift and thrustmust resist and overcome the forces ofgravity and drag.resistanceresistance /r|�zstəns/ noun 1. aforce that opposes 2. the opposition of abody or substance to current passingthrough it � The shunt coil is made offine wire which gives a high resistanceand small current flow.resistantresistant /r|�zst(ə)nt/ adjectivereferring to something which is unaf-fected by a force, process or substance� crash resistant and heat resistantmaterials � Some alloys are less resist-ant to corrosion than others.resistiveresistive /r|�zstv/ adjective refer-ring to resistance � Windscreen heatingand electrical de-icing systems areresistive load circuits.


195 resultantresistorresistor /r |�zstə/ noun a device usedto control current in an electric circuitby providing a resistance � Componentssuch as resistors, rectifiers and internalswitches are all embedded in micro-sizesections of semi-conductor material.respectrespect /r |�spekt/ noun � in somerespect in some way � The flat chartinevitably misrepresents the Earth’ssurface in some respect. � with respectto concerning or with reference to �

Frost point is the temperature to whichair must be cooled at constant pressurein order to reach a state of saturationwith respect to ice.respectiverespective /r |�spektv/ adjectivereferring to two or more persons orthings regarded individually � The pas-sengers returned to their respectiveseats. � The temperature and pressureof the fuel supply are electrically trans-mitted to their respective indicators, i.e.temperature to the temperature gaugeand pressure to the pressure gauge.respondrespond /r |�spɒnd/ verb 1. to reply orto answer 2. to react, to act in return �the aircraft responds to the controlsthe aircraft attitude changes as a resultof the pilot’s movements of the flyingcontrolsresponderresponder /r |�spɒndə/ noun same astransponderresponseresponse /r|�spɒns/ noun 1. ananswer or reply � transponder response� Despite repeated air traffic controltransmissions, there was no responsefrom the pilot. 2. a reaction � inresponse to as a reaction to � The pri-mary function of the outflow valves is toregulate the discharge of cabin air inresponse to the pressure signalsreceived from the controller.responsibilityresponsibility /r |�spɒns |�blti/noun the condition of being responsible� It is the responsibility of the captain toorder an evacuation.responsibleresponsible /r|�spɒnsb(ə)l/ adjec-tive 1. being a source or cause � Frontalsystems are responsible for much of theweather and clouds which occur in tem-perate latitudes. 2. directing or being incharge, and open to blame if somethinggoes wrong � Cabin crew are responsi-

ble for the well-being of passengers. �responsible to someone answerable forone’s actions to somebody highlyplacedrestorerestore /r|�stɔ�/ verb to return some-thing to its original or normal condition� Loss of engine power should be fullyrestored when the control is returned tothe cold air position.restrictrestrict /r |�strkt/ verb 1. to make freemovement limited or difficult � Thenarrow aisles of the aircraft restrict therapid movement of people. 2. to limit �during the bomb-scare, entry to theairport was restricted to authorisedpeople only only authorised peoplecould enter the airportrestricted area

restricted area /r|�strktd �eəriə/noun airspace of a particular length,width and depth, within which the flightof an aircraft must be carried out inaccordance with particular conditionsrestrictionrestriction /r |�strkʃ(ə)n/ noun 1. anarrowing or partial blockage � Anyrestriction in a pipeline will increaseliquid velocity and produce turbulence.2. a limitation � There are restrictionson the taking of photographs in thevicinity of the airport.restrictor valverestrictor valve /r |�strktə v�lv/noun a valve designed to permit limitedflow in one direction and full flow in theother direction � The extent to which theoil pressure will fall depends on the sizeof the restrictor valve.resultresult /r|�z�lt/ noun a consequence oroutcome � Engine oil and cylinder tem-perature will also increase as a result ofhigher combustion temperatures. � verb� to result from to happen as a conse-quence � The structural weaknessresulted from a minor collision whiletaxiing two years previously. � to resultin to produce as an effect � Failure tosecure seat belts could result in seriousinjury.resultantresultant /r |�z�ltənt/ adjective thathappens as a result of something � Thetemperature of the land rises, causingthe layer of air in contact with it towarm up and expand with a resultantdecrease in density. � noun one vectorthat is the equivalent of a set of vectors


retain 196

� When two or more velocities actsimultaneously on a body, the aircraftmovement is called the resultant veloc-ity due to the two or more componentvelocities.retain

retain /r |�ten/ verb to keep or to hold� Retentivity is the ability of a materialhas to retain magnetism. � When fuel-dumping, sufficient fuel must beretained for landing.retard

retard /r|�tɑ�d/ verb 1. to cause tooccur later, or to delay � On most mod-ern engines the spark is retarded to topdead centre, to ensure easier startingand prevent kick-back. 2. to move back-wards � When reducing power, alwaysretard the throttles before reducingRPM (revolutions per minute) with thepropeller levers.retentivity

retentivity /�rten |�tvti/ noun theability to remain magnetised after themagnetising force has gone � Steel hashigh retentivity, but soft iron has lowretentivity.retract

retract /r |�tr�kt/ verb to move back,or to raise � Mechanically operatedsequence valves ensure that the landinggear does not extend until the doors areopen and that the landing gear isretracted before the doors close.retractable

retractable /r |�tr�ktəb(ə)l/ adjec-tive possible to pull back or raise �retractable undercarriage an under-carriage which can be raised into thefuselage or wings after use � Early air-craft had non-retractable undercar-riages.retraction

retraction /r |�tr�kʃən/ noun the actof pulling back or raising � retractionof the undercarriage the raising of theundercarriage into the fuselage after usereturn

return /r |�t%�n/ noun the act of comingback or going back to a place � We’rewaiting for the return of the aircraft. �radar return radar echo � adjective �return flight a flight back to the pointof departure � verb to cause to comeback or to go back to an earlier positionor place � Fly from A to B and return. �The auto-control will return the ailer-ons to neutral as the aircraft returns tolevel flight.

return valve

return valve /r|�t%�n v�lv/ noun avalve which allows flow of fluid in bothdirectionsreveal

reveal /r|�vi�l/ verb to allow to be seen� Radiographic inspection of the air-craft structure is able to reveal fatiguecracks without the need to dismantle theaircraft.reversalreversal /r |�v%�s(ə)l/ noun a changeto the opposite position, direction, ororder � Stationary eddies can be haz-ardous, not only because of the downcurrents but also because an aircraftencountering the reversal of directionmight have its airspeed momentarilyreduced below stalling speed.reverse

reverse /r|�v%�s/ noun the opposite �

One would expect a unit of humid air tobe heavier than a similar unit of dry airbut, in fact, the reverse is true. � adjec-tive going backwards or in the oppositedirection � reverse flow the flow of afluid in the opposite direction to normal� verb to go backwards or in the oppo-site direction � to reverse a vehicle tomake a vehicle go backwardsreverse panic

reverse panic /r|�v%�s �p�nk/ nouna form of shock which makes passen-gers unable to comprehend the need forurgencyreverser

reverser /r |�v%�sə/ noun � thrustreverser a device to change the direc-tion of thrust so that it operates in theopposite direction to the normal direc-tion � In many turbo-jet thrust revers-ers, clamshell doors direct the exhaustgases forward.reverse thrust

reverse thrust /r|�v%�s �θr�st/ nounthrust in the opposite direction to nor-mal in order to decelerate the aircraftafter landingreversiblereversible /r|�v%�sb(ə)l/ adjectivethat can be made to go backwards or tochange direction � a reversible electricmotorreversible pitch propeller

reversible pitch propeller /r |

�v%�səb(ə)l �ptʃ prə |�pelə/ noun a pro-peller which allows the aircraft to bepropelled backwards when taxiingreversion

reversion /r|�v%�ʃ(ə)n/ noun a returnto an earlier condition or state � Insmaller aircraft, reversion to manual


197 RIS

control is possible if complete loss ofhydraulic power occurs.revertrevert /r|�v%�t/ verb to return to an ear-lier condition or state � The elevatorsystem has the ability to revert to man-ual control after a hydraulic failure.revolutionrevolution /�revə |�lu�ʃ(ə)n/ noun arotation or turn about an axis � a revo-lution of the crankshaft a 360° turn ofthe crankshaftrevolutions per minuterevolutions per minute/�revəlu�ʃ(ə)nz pə �mnt/ noun thespeed of an engine or the number ofrotations of the crankshaft per minute �Rpm is the number of revolutions perminute that the engine crankshaft ismaking. � The actuator control is sensi-tive to engine rpm. Abbreviation rpm,r.p.m.revolverevolve /r|�vɒlv/ verb to turn about anaxis � The Earth revolves around thesun.revolvingrevolving /r |�vɒlvŋ/ adjective �tropical revolving storm an intensedepression of a kind that can developover tropical oceans � Tropical revolv-ing storms originate within 5–15° of theequator. � Tropical revolving stormsgenerally occur from June to October.rhumbrhumb /r�m/ noun one of the points ofa compassrhumb linerhumb line /�r�m lan/ noun 1. a reg-ularly curved line on the surface of theEarth which cuts all meridians at thesame angle 2. a steady course taken byaircraft along one compass bearingrhumb line directionrhumb line direction /�r�m landa|�rekʃ(ə)n/ noun the average of allthe great circle directions between thetwo points � Because the great circledirection between two points on the sur-face of the Earth is not constant, it isoften more convenient to consider therhumb line direction.ribrib /rb/ noun one of many cross piecesof the airframe that provide an aircraftwing with shape and strength � Addi-tional strength is required for the ribsections which are placed in the area ofthe undercarriage mountings, flaps andpower plant attachment point.richrich /rtʃ/ adjective referring to a mix-ture in which the ratio of fuel to air is

greater than usual � Moving the mixturecontrol lever forward to the rich posi-tion increases the amount of fuel mixingwith the air.rich mixture

rich mixture /�rtʃ �mkstʃə/ noun afuel/air mixture in which the proportionof fuel is greater than normalridge

ridge /rd"/ noun 1. a long narrow hillwith a crest � The mountain ridgestretches for miles. 2. a long zone of rel-atively high atmospheric pressure � aridge of high pressure � On average, thewind backs with the passage of a ridge.ridge waves

ridge waves /�rd" wevz/ pluralnoun oscillations about the stable stateof the undisturbed air flow with therange of hills providing the disturbancerigging position

rigging position /�r$ŋ pə |�zʃ(ə)n/noun an attitude of the aircraft in whichthe lateral axis and usually the longitu-dinal axis are horizontal � The aircraftwas put into the rigging position.rigid

rigid /�rd"d/ adjective unbending,inflexible � The areas between the ribsare utilised to house fuel tanks whichcan be either rigid or flexible. Oppositeflexible � rigid pipes pipes that do notbend easily � a rigid structure a firmunbendable structurerigidity

rigidity /r|�d"dti/ noun inflexibility,stiffness � Extra strength and rigiditymust be provided in the tail section foraircraft with a tail wheel unit. Oppositeflexibilityrim

rim /rm/ noun the outer edge of some-thing circular, e.g. a wheel � Creepmarks are painted on the tyre and thewheel rim. � The rim of the air intake isprone to icing.rime ice

rime ice /�ram as/ noun ice formedwhen individual droplets of waterfreeze rapidly on striking the aircraftsurfacering

ring /rŋ/ noun a circle � Around theimpeller is a ring of stationary vanescalled a diffuser ring.ripcord

ripcord /�rpkɔ�d/ noun a cord that ispulled to release a parachute from itspack and open itRIS

RIS abbreviation radar informationservice


rise 198riserise /raz/ noun 1. an increase � a risein temperature 2. � to give rise to tocause � Hills and mountains may giverise to particularly severe turbulence. �verb 1. to move upwards � air rises 2. toincrease � The temperature is rising. �

raiseriskrisk /rsk/ noun the possibility of suf-fering harm or injury, danger � Whenstarting an engine, it is bad practice topump the throttle lever as there is a riskof fire in the carburettor air intake. �

verb to take a dangerous chance � torisk the lives of passengers to put thelives of passengers in danger by takinga particular course of actionrivetrivet /�rvt/ noun a type of metal boltor pin with a head on one end, insertedthrough one of the aligned holes in theparts to be joined and then compressedon the plain end to form a second head� Tensile or compressive loading makesthe joined materials tend to slide andbreak the rivet or bolt. � verb to joinwith rivets � The skin is riveted to bothstringers and frames.RMIRMI abbreviation radio magnetic indi-catorRNAVRNAV abbreviation area navigationrobot pilotrobot pilot /�rəυbɒt �palət/ nounsame as autopilotrocker armrocker arm /�rɒkə ɑ�m/ noun part ofthe valve mechanism in an internalcombustion engine, which transmits themovement of the pushrod to the valverodrod /rɒd/ noun a thin straight piece ofmetal � Aluminium rods and bars canreadily be employed in the high-speedmanufacture of parts.rogallorogallo /rɒ|�$�ləυ/ noun a fabric-cov-ered delta-shaped wing that can befolded compactly, used on ultralight air-craftrolerole /rəυl/ noun function � Movementof air plays a major role in the develop-ment of weather patterns. � the role ofthe aircraft the type of operation theaircraft is required to performrollroll /rəυl/ noun 1. a rotation about thelongitudinal axis of the aircraft, createdby movement of the ailerons � Roll isproduced by moving the stick to the leftor right. � bank 2. a flight manoeuvre

with 360° rotation about the longitudi-nal axis of the aircraft � Loops and rollsare aerobatic manoeuvres. � verb torotate the aircraft around its longitudi-nal axis � Move the control column tothe left to roll the aircraft to the left. � toroll into a turn to roll or bank the air-craft so that it turns left or right � Byrotating the yoke the ailerons are movedand the aircraft rolls into a turn.

COMMENT: The difference betweenroll and bank is that roll is movementwhereas bank suggests a fixedattitude of the aircraft. Consequently, aturn might be expressed in angles ofbank: turn at a bank angle of 30°, andthe movement to obtain the bankmight be expressed as roll: roll theaircraft to the left.

roll cloudroll cloud /�rəυl klaυd/ noun cloudcreated in the rotor zone on the down-wind side of mountain rangesrollerroller /�rəυlə/ noun a cylindrical metaldevice which rotates � The most com-mon bearings used in gas turbineengine are the ball or roller type.RONRON abbreviation remain overnightrootroot /ru�t/ noun � the root of theproblem the cause of the problemroserose /rəυz/ noun � compass rose thecompass card or its marking of 32points on a map � An arc of the compassscale, or rose, covering 30° on eitherside of the instantaneous track, is at theupper part of the display.rotaryrotary /�rəυtəri/ adjective rotating �rotary motion rotating movementrotary actuatorrotary actuator /�rəυtəri��ktjuetə/ noun an actuator whichrotates and operates a screw jack, e.g. toextend flapsrotary inverterrotary inverter /�rəυtəri n|�v%�tə/noun a DC motor driving an AC gener-ator, the output of which must be regu-lated to give constant voltage and fre-quencyrotary wing aircraftrotary wing aircraft /�rəυtəri wŋ�eəkrɑ�ft/ noun an aircraft with a rotorwhich provides lift, such as a helicopterrotaterotate /rəυ |�tet/ verb to turn aroundon an axis or centre � In the event offlame extinction in flight, the enginewill continue to rotate, due to the air-


199 rudder

flow through it caused by the forwardspeed of the aircraft. � The aircraftshould be rotated to the recommendednose-up attitude for touch down. �

Counter-rotating propellers rotate inopposite directions. � rotationrotation

rotation /rəυ |�teʃ(ə)n/ noun 1. the actof moving the control yoke or stick aftto raise the nose of an aircraft during thetake-off run to facilitate the aircraftbecoming airborne � Rotation shouldbegin at about 60 knots. 2. the act ofturning around an axis or centre � therotation of the earth � crankshaft rota-tion � The speed of rotation determinesthe frequency of the generator output.

COMMENT: The aircraft rotates aroundthree axes: pitch = rotation around thelateral axis; roll = rotation around thelongitudinal axis; yaw = rotationaround the vertical axis.

rotational

rotational /rəυ |�teʃ(ə)nəl/ adjectiverotating � rotational movement of thecamshaft � The rotational movement ofthe propeller blades creates lift at rightangles to the blade.rotor

rotor /�rəυtə/ noun a device whichturns about an axis or centre � The rotorblade of a compressor.rotor blade

rotor blade /�rəυtə bled/ noun along thin aerofoil on a helicopter rotorrotorcraft

rotorcraft /�rəυtəkrɑ�ft/ noun sameas rotary wing aircraftrough

rough /r�f/ adjective 1. not smooth,having an irregular surface. Oppositesmooth � rough air turbulent air �rough running referring to a pistonengine which is not operating correctly2. not fully detailed � a rough estimatean approximate calculation, goodenough for a given purpose � a roughdrawing a quick drawing usually usedto illustrate or explainroughness

roughness /�r�fnəs/ noun uneven-ness of a surface � The strength of tur-bulence near the Earth’s surfacedepends largely on the surface temper-ature, the surface wind, and the rough-ness of the surface.rough terrain

rough terrain /�r�f tə |�ran/ noununeven ground

roundround /raυnd/ adjective circular � around life raft � adverb in a circularmovement � The pointer swings round.routeroute /ru�t/ noun a course of travel �

The purpose of charts is to plan and flya safe route to a destination. � en route� verb to plan to send an aircraft, pas-sengers or freight to a place along a par-ticular routeroute flight planroute flight plan /�ru�t �flat �pl�n/noun detailed information concerningan intended flight, provided to an airtraffic control facility in written or oralformroutineroutine /ru�|�ti�n/ noun a standard pro-cedure � Meteorological informationfor scheduled flights will be passed tothe operations department as a matterof routine. � adjective standard and reg-ular � routine servicing servicing car-ried out in the normal way at regular,scheduled intervalsrowrow /rəυ/ noun 1. a series of objects ina line � Each row of rotating rotorblades is followed by a row of station-ary stator blades. 2. a series of seats inan aircraft � There are no empty seats inRow 8.rpmrpm, r.p.m. abbreviation revolutionsper minute � Rpm is the number of rev-olutions per minute that the enginecrankshaft is making. � The actuatorcontrol is sensitive to engine rpm.R/TR/T abbreviation radiotelephony(NOTE: R/T is frequently used in spokenlanguage, whereas RTF is the ICAOabbreviation.)RTFRTF abbreviation radiotelephony(ICAO)rudderrudder /�r�də/ noun a control surfaceon the fin which rotates the aircraftabout its vertical axis to produce yaw �The A320 retains a backup mechanicallinkage for elevator trim and rudder toallow control in the unlikely event ofcomplete electrical failure.

COMMENT: The rudder does not turnthe aircraft. It is used, together withaileron deflection, to initiate turns, tobalance forces in turns and tocounteract yawing motions created bythe propeller during flight. The rudderpedals are mounted on the floor of thecockpit.


rudder ball 200rudder ballrudder ball /�r�də bɔ�l/ noun sameas inclinometerrudder pedalrudder pedal /�r�də �ped(ə)l/ noun afoot-operated lever which moves therudder � Just before take-off, the pilotshould make sure that his or her feet arecorrectly positioned on the rudder ped-als.rulerule /ru�l/ noun 1. a standard andauthoritative instruction or guide �

According to the rules, your ticket mustbe paid for two weeks in advance. � asa rule usually � As a general rule, radiosignals travel in straight lines. 2. aninstrument for determining lengthrule of thumbrule of thumb /�ru�l əv �θ�m/ nouneasily remembered, useful guide to amore complex principlerunrun /r�n/ noun a route or distance �

verb 1. to extend � Magnetic lines offorce run from the north magnetic poleto the south magnetic pole. 2. to operatean engine � An engine should be run atlow r.p.m. (revolutions per minute) afterflight to allow engine components tocool to a more uniform temperature.run uprun up /�r�n ��p/ noun � engine run-up the testing of a piston engine at highpower, in a light aircraft, just beforetake-off � Make certain that the parkingbrake is on before doing engine run-upchecks.runwayrunway /�r�nwe/ noun a strip oflevel, usually paved ground on which

aircraft take off and land � Heathrowairport has four terminals and two mainrunways. � To achieve a safe landing,an aircraft has to be controlled so thatits wheels make contact with the run-way smoothly. � The aircraft lined upperfectly on the runway extended centreline. Abbreviation R/W

COMMENT: Large airports often havemore than one runway, arranged tocope with varying wind directions.Some busy airports have parallelrunways which can be usedsimultaneously.

runway visual range

runway visual range /�r�nwe�v"uəl �rend"/ noun the distancealong a runway at which selected lightscan be seen, adjusted to simulateapproach visibility � Runway visualrange is obtained by an observer stand-ing at the side of the runway in thevicinity of the threshold counting thenumber of markers or lights visiblealong the side of the runway. Abbrevia-tion RVRrupture

rupture /�r�ptʃə/ noun the process ofbreaking open or bursting � Pressure inthe fuel tanks must be controlled to pre-vent rupture or collapse. � verb to breakopen or burst � The impact ruptured thefuel tank.RVR

RVR abbreviation runway visual rangeR/W

R/W, RWY abbreviation runway


SS

S abbreviation southsafe

safe /sef/ adjective free from danger �Approach to land must be made at asafe speed. � safe landing a landingwhich does not endanger people ordamage the aircraft. � fail safesafeguard

safeguard /�sef$ɑ�d/ noun some-thing done as a precaution � A propelleris feathered after engine failure, or as asafeguard when low oil pressure orexcessive temperature have indicatedthe development of a possible defect. �

verb to take action to make sure thatsomething is protected from harm � Apressure maintaining valve is generallyused to safeguard operation of impor-tant services, such as flying controlsand wheel brakes.safe life

safe life /�sef laf/ noun the principleof putting the least load or force on eachcomponent, so that it will last wellbeyond a plane’s expected lifesafety

safety /�sefti/ noun freedom fromdanger, injury or risk � Turbulence canhave serious effects on aircraft safetyand performance and makes air traveluncomfortable. � safety conscious thestate of being aware at all times of theimportance of safety and the means bywhich it is achieved and maintainedsafety pilot

safety pilot /�sefti �palət/ noun apilot present in the cockpit to ensure thesafety of the flight, e.g. when a studentis practising instrument flyingsafety regulations

safety regulations /�sefti�re$jυleʃ(ə)nz/ plural noun rules orlaws which must be followed to make aplace safe � Equipment and furnishingson modern jet transports must comply

with safety regulations concerning fireresistance.safety straps

safety straps /�sefti str�ps/ pluralnoun device to keep a person in positionin a seatsailplane

sailplane /�selplen/ noun a lightglider particularly well adapted to mak-ing use of rising air currentsSt Elmo’s Fire

St Elmo’s Fire /sənt �elməυz �faə/noun a luminous electrical dischargesometimes seen on aircraft duringstormsSALR

SALR abbreviation saturated adiabaticlapse ratesalvage

salvage /�s�lvd"/ verb to save itemsof property which may be in danger ofbeing lost � In the event of a crash land-ing in a remote area on land, an attemptshould be made to salvage all items ofsurvival equipment from the wreckageincluding beacons, rafts and raft equip-ment.sample

sample /�sɑ�mpəl/ noun a smallamount which is representative of thewhole � If a sample of fuel taken from atank was found to be hazy or cloudy inappearance, this would indicate thepresence of water in suspension. � Iffuel contamination by water is sus-pected, a sample of fuel should bedrained from the tank for inspection.sandwich

sandwich /�s�nwd"/ noun a con-struction of three layers, the material ofthe one in the middle being differentfrom the two on each side � Standardconnectors consist of a metal couplingwith a rubber sandwich joint.SAR

SAR abbreviation 1. special aerodromereport 2. search and rescue (ICAO)


SAS 202SAS

SAS abbreviation stability augmenta-tion systemsatellite

satellite /�s�təlat/ noun an objectlaunched to orbit the earth, usuallyreceiving and transmitting signals, pic-tures and data � Satellite communica-tions improve the effective distributionof world area forecasts.satellite navigation

satellite navigation /�s�t(ə)lat�n�v|�$eʃ(ə)n/, satellite navigationsystem noun a system of navigationwhich uses orbiting satellites to deter-mine the position of an aircraft or point,in relation to the Earth’s surface. Abbre-viation SATNAVsatisfactory

satisfactory /�s�ts|�f�kt(ə)ri/adjective adequate, good enough � Forsatisfactory operation, an enginerequires an adequate supply of oil.

‘…during the engine run-up, check thatthe use of carburettor heat gives asatisfactory drop in rpm or manifoldpressure’ [Civil Aviation Authority,General Aviation Safety Sense Leaflet]

satisfy

satisfy /�s�tsfa/ verb 1. to meet aparticular prescribed standard � ShellAvgas 100LL satisfies British specifica-tion. 2. to meet the needs or require-ments of something � To satisfy therequirements of aviation there are threetypes of meteorological offices for avia-tion, each with a specific role to fulfil.SATNAV

SATNAV /�s�tn�v/ abbreviation sat-ellite navigationsaturate

saturate /�s�tʃəret/ verb to cause asubstance to combine with the greatestpossible amount of another substance �When a sample of air contains the max-imum amount of water vapour for itsparticular temperature, it is said to besaturated. � lapse ratesaturation

saturation /�s�tʃə |�reʃ(ə)n/ nounthe state of being filled with the maxi-mum amount of something which canbe absorbed, e.g. a sample of air whichcontains the maximum amount of watervapour for its temperature � The vari-ous types of fog are classified by themanner in which saturation is reached.� the moisture in the air reached sat-uration point and fell as rain the aircould absorb no more water

saturation pointsaturation point /�s�tʃə|�reʃ(ə)npɔnt/ noun the level at which no moreof a substance can be absorbedsavesave /sev/ verb to prevent unneces-sary use of � Electro-magnetic switchesare generally used to control high-cur-rent devices by means of a small currentthus saving heavy duty cable and there-fore weight.SBSB abbreviation service bulletinscalescale /skel/ noun 1. marks at fixedintervals used as a reference standard inmeasurement � This ruler has scales ininches and centimetres. 2. a graded sys-tem of classification 3. a proportionused in determining distance on charts �Many aeronautical charts use a scale of1:500,000.scanscan /sk�n/ verb 1. to look at quicklyand systematically � The pilot is trainedto scan the instrument panel. 2. to movea radar beam in a systematic pattern insearch of a target � Some radars scan inazimuth and glideslope.scatterscatter /�sk�tə/ noun deflection ofradiation � High frequencies are freer ofionospheric scatter and are relativelyfree of noise.scheduleschedule /�ʃedju�l/ noun 1. a list oftimes of departures and arrivals � anairline schedule 2. a printed or writtenlist of items in the form of a table �

inspection schedule � maintenanceschedule � verb 1. to plan for a particu-lar time or date � The meeting is sched-uled for 3 o’clock. 2. to enter on aschedule � Calculate and schedule eachitem on the proper form.scheduledscheduled /�ʃed"u�ld/ adjective �scheduled landing an arrival at a time-tabled destinationscheduled flightsscheduled flights /�ʃed"u�ld�flats/ plural noun flights that are listedin the airline timetable, as opposed tocharter flightsschematicschematic /ski� |�m�tk/ adjectiveshowing the function of a device or sys-tem without trying to create a realisticimage � Figure 3 shows a schematicdiagram of the autopilot.scramjetscramjet /�skr�md"et/ noun a ram-jet aircraft in which fuel is burned in airthat is moving at supersonic speeds


203 secondary surveillance radarscreenscreen /skri�n/ noun the surface of aTV or computer monitor on which theimage is seen � The airborne weatherradar (AWR) allows the range of cloudto be estimated from range markers dis-played on the screen.screwscrew /skru�/ noun a type of threadedconnector used to fix things together byrotating itscrew jackscrew jack /�skru� d"�k/, screw-jack /�skru�d"�k/ noun a lifting deviceworking with rotary input � Pitch trimis achieved by lowering or raising thetailplane leading edge with a screw jackpowered by two hydraulic motors.seasea /si�/ noun 1. a body of salt waterbetween land masses � Swissair flight111 crashed into the sea. � mean sealevel the average level of the sea takingtidal variations into account � Altitudeis the vertical distance between an air-craft – or a point or a level – and meansea level. 2. a particular area of a bodyof salt water � the North Sea � the SouthChina Sea � oceansea-anchorsea-anchor /�si� ��ŋkə/ noun adevice under a raft to provide stability �Each life raft is equipped with a flameorange coloured canopy and a sea-anchor.seaboardseaboard /�si�bɔ�d/ noun US a coast� the eastern seaboard of the USAsealseal /si�l/ noun 1. a device that joinstwo parts and prevents leakage � An oilseal reduces the clearance between therotating and static members. � staticseal a seal which is part of a non-mov-ing component � Static seals, gasketsand packing are used in many locations.2. a way in which a liquid or a gas maybe prevented from escaping � Staticseals, gaskets and packing effect a sealby being squeezed between two sur-faces. � verb to join two parts in such away as to prevent leakage � In pressu-rised aircraft, bulkheads are providedat the front and rear ends of the fuselageto seal off the crew compartment andthe passenger cabin.sealantsealant /�si�lənt/ noun a substancepainted or sprayed onto a surface to pre-vent the escape of a liquid or gas � Theintegral fuel tank may be completely

coated on the inside with a layer ofsealant.sea levelsea level /�si� �lev(ə)l/ noun the aver-age level of the surface of the sea, usedfor measuring barometric pressuresealing compoundsealing compound /�si�lŋ�kɒmpaυnd/ noun same as sealantseaplaneseaplane /�si�plen/ noun a plane thatcan take off from and land on watersearchsearch /s%�tʃ/ noun an act of lookingfor something in order to find it � Theaircraft reduced altitude and carriedout a visual search for survivors. � verbto look for in order to find something �

The investigators searched the scene ofthe crash for the flight data recorder.seasonseason /�si�z(ə)n/ noun one of thefour natural divisions of the year,spring, summer, autumn, or winter �

The amount of solar radiation receivedby the Earth depends on the season.seasonalseasonal /�si�z(ə)n(ə)l/ adjective 1.referring to the four natural divisions ofthe year, or characteristic of a particulartime of the year � seasonal tempera-tures � seasonal winds 2. only lastingfor a season � seasonal workseasonal variationseasonal variation /�si�z(ə)n(ə)l�veəri|�eʃ(ə)n/ noun a change occur-ring according to the seasonseatseat /si�t/ noun a place for sitting �

pilot’s seat � window seat a seat next toa windowseatedseated /�si�td/ adjective sitting, onyour seat � Passengers should remainseated. � sitseating capacityseating capacity /�si�tŋ kə|�p�sti/noun the maximum number of peoplean aircraft, bus, etc., can seatsecondarysecondary /�sekənd(ə)ri/ adjective1. of the second rank in importance,etc., not primary 2. an induced currentthat is generated by a primary sourcesecondary radarsecondary radar /�sekənd(ə)ri�redɑ�/ noun a radar system in whichthe active target replies to the interroga-tion unitsecondary surveillance radarsecondary surveillance radar/�sekənd(ə)ri sə |�veləns |�redɑ�/noun a radar which uses ground equip-ment called interrogators and airborneequipment called transponders to


section 204

identify aircraft, determine altitude andrange, etc. � Secondary surveillanceradar (SSR) is normally used to supple-ment data from primary systems.Abbreviation SSRsectionsection /�sekʃən/ noun 1. a compo-nent or part of a structure � tail sectionand nose section of the aircraft � thenon-smoking section of the aircraft 2.part of a text � The book is divided intofour sections, and the first four chaptersform the first section. 3. a diagram of asolid object as it would appear if cut, sothat the internal structure is displayed. �cross-sectionsectionalsectional /�sekʃən(ə)l/ adjective 1.referring to a section or composed ofsections 2. showing a solid object as itwould appear if it were cutsectorsector /�sektə/ noun 1. part of theflight between an aircraft moving underits own power until it next stops afterlanding in its allocated parking position� On some sectors, because of fuel costsat the destination, it can be economicalto carry excess fuel. 2. the portion of acircle inside two radii and the includedarc 3. a segment of airspace with itsown team of air traffic controllerssecuresecure /s |�kjυə/ adjective fastened orlocked, safe � Overhead baggage lock-ers must be secure. � verb to attachfirmly, to fasten or to make safe � If theonset of turbulence is sudden, crewmust immediately secure themselves inthe nearest available seats.securitysecurity /s |�kjυərti/ noun 1. safety2. people whose job is to protect build-ings or other people against crimeSELCALSELCAL noun a high-frequency radiosystem which alerts the crew of an air-craft to the fact that air traffic control istrying to contact them. Full form selec-tive callseldomseldom /�seldəm/ adverb not often,rarely � Aircraft are seldom hit by light-ning. � The wet sump system of lubrica-tion is seldom used on modern aircraft.selectselect /s|�lekt/ verb to choose some-thing such as a particular instrument orsystem setting � A reverse thrust leverin the crew compartment is used toselect reverse thrust. � The cabin pres-

sure controller is used to select cabinaltitude.selectionselection /s |�lekʃən/ noun 1. achoice of something such as a particularinstrument or system setting � By man-ual selection of the heating switch, theformed ice can be dispersed. 2. a collec-tion of carefully chosen things � aselection of photographsselectorselector /s |�lektə/ noun a manuallyoperated device like a switch, whichoffers a choice of settings � Turn theselector control. � The purpose of thisselector is to direct fluid to the appro-priate side of an actuator.self-containedself-contained /�self kən|�tend/adjective independent � The auxiliarypower unit is a self-contained unit.self-positioningself-positioning /�self pə |

�zʃ(ə)nŋ/ noun the positioning of theaircraft on the extended centreline ofthe runway using the on-board naviga-tion system. Also called centre fixsemi-semi- /semi/ prefix halfsemicirclesemicircle /�semi|�s%�k(ə)l/ noun halfa circle � Most mathematical protrac-tors are made of plastic in the shape ofa semicircle.semicircularsemicircular /�semi |�s%�kjυlə/ adjec-tive in the shape of half a circle � Mostmathematical protractors are semicir-cular in shape.semiconductorsemiconductor /�semikən |�d�ktə/noun a solid crystalline substance withelectrical conductivity greater thaninsulators but less than good conductors� Semiconductor material is used tomake many electronic devices.seniorsenior /�si�niə/ adjective older ormore important in rank � senior cabinsupervisorsensesense /sens/ noun 1. manner, way �

After turning the aircraft, the auto-con-trol will operate in the opposite senseand return the ailerons to neutral as theaircraft returns to level flight. 2. any ofthe physiological means by which weexperience our surroundings: sight,hearing, smell, taste and touch � Whenflying in cloud, pilots must rely on theinstruments and not on their senses. 3.wisdom or natural intelligence � He hasa lot of (common) sense. 4. the meaning


205 serviceability

of a word � The word ‘bearing’ is usedin a lot of different senses. � verb todetect automatically � The fire warningsystem is designed to sense two levels oftemperature – overheat and fire. � sen-sorsensitivesensitive /�senstv/ adjective able toregister very small differences orchanges in conditions � Oscillating out-puts from the alternators could causesensitive equipment to malfunction ortrip off. � The actuator is sensitive toengine rpm.sensitivitysensitivity /�sens|�tvti/ noun thequality or state of being able to registervery small differences or changes inconditions � Monitors detect distur-bances which are below the sensitivitylevel of the gyros.sensorsensor /�sensə/ noun a device whichreceives and responds to a signal orstimulus � pressure sensor � tempera-ture sensor � The inlet pressure issensed by a single pitot-type sensorprobe which is situated just in front ofthe compressor.separateseparate adjective /�sep(ə)rət/ exist-ing as an independent thing � Propel-lers consist of a number of separateblades mounted in a hub. � verb/�sepəret/ to set or keep apart � Drychemical extinguishants separate theoxygen element from the fire thusretarding combustion.separationseparation /�sepə |�reʃ(ə)n/ noun 1.the condition of being spaced apart 2.the removal of something from a mix-ture or combination � The oil and airmixture flows over the de-aerator trayin the oil tank, where partial separationtakes place.separation standardsseparation standards /�sepə |

�reʃ(ə)n �st�ndədz/ plural noun inter-nationally agreed minimum separationlimits for aircraft in flightseparatorseparator /�sepəretə/ noun a devicewhich removes something from a mix-ture or combination � The water sepa-rator will extract a percentage of freemoisture from the air.sequencesequence /�si�kwəns/ noun a seriesof things or events which follow oneanother, an order � The ignition system

provides a rapid series of sparks timedto fire in each cylinder in the correctsequence.sequence valves

sequence valves /�si�kwənsv�lvz/ plural noun a fluid flow control-ler which performs a number of actionsin a particular order � Sequence valvesare often fitted in a landing gear circuitto ensure correct operation of the land-ing gear doors and actuators.series

series /�səri�z/ noun a number ofthings or events which come one afterthe other in a particular order � a seriesof photographs � a series of switchesseries circuit

series circuit /�səri�z �s%�kt/ nounan electric circuit connected so that cur-rent passes through each component ofthe circuit in turn without branchingserious

serious /�səriəs/ adjective important,or giving cause for great concern orworry � serious damage very bad dam-age � serious injury very bad injuryserve

serve /s%�v/ verb 1. to act or to func-tion as � In some aircraft, pressuregauges also serve as a maintenancecheck on leakage. 2. to be used for apurpose � Different colour-coded warn-ing lights serve to alert the observerthat something is wrong with the sys-tem.

‘…a recent incident in Argentina servesto highlight some of the many safetyproblems in Latin America’[INTER PILOT]

service

service /�s%�vs/ noun 1. a facility � Apressure reducing valve is often used toreduce main system pressure to a valuesuitable for operation of a service suchas the wheel brakes. 2. work done forothers as a profession � Automatic Ter-minal Information Service (ATIS) �

Cabin crew provide a commercial serv-ice to passengers. 3. maintenance orrepairs carried out � verb to do mainte-nance or repairs on � Jet engines aresimpler to dismantle and service thanpiston engines.serviceability

serviceability /�s%�vsə |�blti/ nounthe ability to function as required �

When carrying out engine checks, it isusual to turn off the magnetos in turn tocheck their serviceability.


serviceable 206serviceableserviceable /�s%�vsəb(ə)l/ adjectiveable to function as required � The pilotmust make sure that the radio equip-ment is serviceable prior to take-off.service areaservice area /�s%�vs �eəriə/ nounarea where maintenance and repairs arecarried outservice bayservice bay /�s%�vs be/ noun aspace in the structure of an aeroplanewhere equipment can be located formaintenance or repairs � In most mod-ern aircraft a number of the major com-ponents are grouped together in ahydraulic service bay which is easilyaccessible for routine servicing opera-tions.service bulletinservice bulletin /�s%�vs �bυltn/noun a notice issued by the manufac-turer of an aircraft, engine or otherequipment to alert people to problemswith that equipment. Abbreviation SBservicingservicing /�s%�vsŋ/ noun the actionof carrying out maintenance and repairs� Accessibility of components andequipment during servicing enableswork to be done more quickly.servoservo /�s%�vəυ/ abbreviation servo-mechanismservo-assistedservo-assisted /�s%�vəυ ə |�sstd/adjective partially operated by a servo-mechanism � servo-assisted brakes �

servo-assisted steeringservo-control unitservo-control unit /�s%�vəυ kən |

�trəυl �ju�nt/ noun a unit, a combinedselector valve and actuator, whichmoves a control surface � A servo-con-trol unit is part of the system whichrelieves the effects of aerodynamicforces on the flight controls.servomechanismservomechanism /�s%�vəυ |

�mekənz(ə)m/ noun a device to con-vert input forces into much larger out-put forces � Two phase motors are nor-mally used for very small or miniaturemotors in servomechanisms.setset /set/ noun a group of things whichbelong together � a set of instruments �a set of figures � adjective fixed orestablished � a set procedure � verb 1.to adjust to a particular point or figure �The aircraft receiver is set to therequired frequency. 2. to put in a partic-ular position � Set the throttle fully

closed. 3. to harden � The resin sets.(NOTE: setting – set) � cold settingmaterials materials which do not needheat to hardenset downset down /�set �daυn/ verb to land anaircraft, or land somewhere in an air-craftsettingsetting /�setŋ/ noun 1. a particularfigure or position which a device isadjusted to � altimeter setting adjust-ment of the sub-scale of the altimeter toread QFE, QNH, etc. 2. the action ofadjusting a device to a particular posi-tion, etc. � The setting of the altimeter isdone prior to take-off.settlesettle /�set(ə)l/ verb to move into afinal position � When wheels are firstfitted to an aircraft, the tyres tend tomove slightly as they settle down on therims.severalseveral /�sev(ə)rəl/ adjective anumber of but not many, more than afew � There are several types of instru-ment landing systems (ILS) in use. �several minutes a number of minutesseveresevere /s|�və/ adjective extreme orintense (NOTE: Generally speaking,weather conditions can be describedas light, moderate or severe, dependingon the amount or intensity of the condi-tion.) � severe icing bad icing � severeturbulence violent turbulenceseverityseverity /s |�verti/ noun the amount,intensity or seriousness of a condition �When the wind is strong the verticalcurrents become quite vigorous with theresultant increase in the severity of tur-bulence.SFARSFAR abbreviation Special FederalAviation Regulationshadeshade /ʃed/ noun 1. intensity or rich-ness of colour � Shades of colour of thelandscape become lighter in misty con-ditions. 2. cover or shelter from the sun� Surface air temperature is the temper-ature recorded in the shade at a heightjust above ground level.shadowshadow /�ʃ�dəυ/ noun an area whichis not affected by full radiation becauseof partial or full blocking of rays bysomething between the area and thesource of the radiation � Solar radiationdoes not exist at night when the rotation


207 shorten

of the Earth creates a shadow zone fromthe sun. � Line-of-sight transmissionpath means that obstacles and terraincan create shadow zones.shaft

shaft /ʃɑ�ft/ noun a long, generallycylindrical bar, especially one thatrotates and transmits power � enginedrive shaft � propeller shaftshaft horsepower

shaft horsepower /�ʃɑ�ft�hɔ�spaυə/ noun the unit used for stat-ing the power delivered to the shaft of aturboshaft or turboprop engine. Abbre-viation SHPshaker

shaker /�ʃekə/ noun a device whichshakes or vibrates violently � Large air-craft use a stick shaker to supplementthe natural stall warning of buffet.shallow

shallow /�ʃ�ləυ/ adjective not deep �shallow angle small angleshallow depression

shallow depression /�ʃ�ləυ d |

�preʃ(ə)n/ noun an area of slightly lowrelative atmospheric pressureshape

shape /ʃep/ noun form � The shapeof an aircraft is determined by therequirement to provide an aerodynamiclift force great enough to support theweight of the aircraft and payloadwhilst in flight.sharp

sharp /ʃɑ�p/ adjective 1. thin andcapable of cutting or piercing � If apiece of thermosetting plastic is hit hardenough, it breaks into pieces withstraight sharp edges. 2. clear � Thesharp setting means the bandwidth isreduced to 1kHz (kilohertz) to minimisenoise or interference. 3. clear and dis-tinct � Cumulus clouds have sharp out-lines. 4. sudden and acute � a sharpincrease a sudden large increaseshatter

shatter /�ʃ�tə/ verb to break into anumber of pieces when hit � Clear ice ishard to shatter and break off.shear

shear /ʃə/ verb to break by lateralmovementshearing load

shearing load /�ʃərŋ ləυd/ nounload caused by sliding apart the layersof a structureshear stress

shear stress /�ʃə stres/ noun stressthat occurs in riveted and bolted jointswhen a force causes one layer of mate-rial to slide over an adjacent layer

shedshed /ʃed/ verb to get rid of � Non-essential loads may need to be shed inorder to reduce weight.sheetsheet /ʃi�t/ noun 1. a large, thin, flatpiece of material � aluminium sheet 2. arelatively large piece of paper �instruction sheet a piece of paper onwhich special instructions are written orprintedshellshell /ʃel/ noun the outer covering ofsomething such as an aircraft fuselageshieldshield /ʃi�ld/ noun a protective cover-ing � heat shield � verb to protect bycovering � The beacon should be sitedon the highest ground to prevent thetransmitted signal from being shielded.shiftshift /ʃft/ noun 1. movement fromone place to another � a shift in position2. a change � When a radio transmis-sion is made from a moving platform,there will be a shift in frequencybetween the transmitted and interceptedradio signals. � verb to change the posi-tion of something � to shift a loadshockshock /ʃɒk/ noun 1. a sudden violentimpact � On all undercarriages someform of accepting the shock of landingmust be included. 2. disturbance ofmental functions caused by a terribleexperience or injury � Crew should beaware of reverse panic, a form of shockwhich makes passengers unable to com-prehend the need for urgency.shock absorbershock absorber /�ʃɒk əb |�zɔ�bə/noun device to minimise the shock tothe main structure of the aircraft when itlandsshock waveshock wave /�ʃɒk wev/ noun com-pression wave caused by supersonicmotion � As sonic speed is approached,the efficiency of the intake begins to fall,because of the formation of shock wavesat the intake lip.shoreshore /ʃɔ�/ noun a stretch of land atthe edge of the sea or a lake, etc. � At aheight of 3,000 feet it was possible tosee the shore. � offshore, onshoreshortenshorten /�ʃɔ�t(ə)n/ verb to make shortor shorter in length or duration � Mis-handling of aero-engines during opera-tion can cause considerable damageand wear which can shorten the life ofthe engine. � The length of the mercury


short-haul 208

column shortens when cooled. Oppositelengthenshort-haulshort-haul /�ʃɔ�t hɔ�l/ adjective trav-elling over a short distanceshort-haul flightshort-haul flight /�ʃɔ�t hɔ�l �flat/noun a flight over a short distance, up to1,000km � On short-haul flights, pas-sengers are usually offered only lightmeals.short-term conflict alertshort-term conflict alert /�ʃɔ�tt%�m �kɒnflkt ə |�l%�t/ noun a warningthat an aircraft may soon be flying tooclose to another aircraftshotshot /ʃɒt/ noun a discharge � Extin-guishing of a fire in an auxiliary powerunit (APU) compartment is normallydone by a single-shot fire extinguisher.showershower /�ʃaυə/ noun a short period ofrain or snow � Showers are forecast forthe evening. � Snow showers areexpected in the area.SHPSHP abbreviation shaft horsepowershroudshroud /ʃraυd/ noun 1. an extensionof a fixed surface of a wing towards therear, which covers the leading edge of amovable surface hinged to it 2. any oneof the lines by which the harness of aparachute is attached to the canopyshuntshunt /ʃ�nt/ noun a low-resistanceconnection between two points in anelectric circuit that forms an alternativepath for a portion of the current � Theshunt-wound generator, used in con-junction with a voltage regulator, is themost common type of DC (direct cur-rent) generator system for aircraft. Alsocalled bypassshuttershutter /�ʃ�tə/ noun a hinged doorwhich controls the flow of air � oilcooler shutters � radiator shuttersSIDSID abbreviation standard instrumentdeparturesidestick controllersidestick controller /�sadstk kən |

�trəυlə/ noun a small side-mountedcontrol column used on aircraft such asthe Airbus A340sightsight /sat/ noun 1. view � The fogcleared and the mountain came intosight. 2. � with the airfield in sight atransmission to air traffic control toconfirm that the pilot can see the land-ing airfield 3. the ability to see using the

eyes � verb to see something when it isa long way away � Sea marker dyes canonly be used once and should only beused when a search aircraft is sighted.sight glass

sight glass /�sat $lɑ�s/ noun a sim-ple fluid-level gaugeSIGMET

SIGMET /�s$met/ abbreviation sig-nificant meteorological informationsignsign /san/ noun 1. a small quantity oramount of a something which may sug-gest the existence of a much largerquantity � Any sign of smoke or fire out-side a wing exit means it cannot beused. 2. a display with letters and/ornumbers, sometimes lit up � the ‘fastenseat belt’ sign � ‘no-smoking’ sign 3. asymbol such as: -, +, x or ÷, which rep-resents an operation � verb to put one’ssignature on a document, a letter, etc. �

Remember to sign the letter.signalsignal /�s$n(ə)l/ noun 1. a device,action or sound which passes informa-tion 2. a radio wave transmitted orreceived � As a general rule, radio sig-nals travel in straight lines.signals area

signals area /�s$n(ə)lz �eəriə/ nounan area on an aerodrome used for dis-playing ground signalssignals mast

signals mast /�s$n(ə)lz mɑ�st/noun a vertical pole on an airfield fromwhich signal flags are flownsignals squaresignals square /�s$n(ə)lz skweə/noun an area on an aerodrome fromwhich ground signals are displayedsignaturesignature /�s$ntʃə/ noun the nameof a person written in a special way toshow that a document has been author-ised or to show who is the author of aletter, etc. � Look at the signature to seewho wrote the letter.significance

significance /s$ |�nfkəns/ nounimportance � Except near a coastlinewhere the sea breeze may augment theupslope motion, anabatic winds are oflittle significance.significantsignificant /s$ |�nfkənt/ adjectiveimportant and therefore noticeable � asignificant change in temperature � Thevertical currents and eddies formed bythe flow of air over hills and mountainshave a significant effect on aircraftencountering them.


209 sitsignificant meteorological informationsignificant meteorologicalinformation /s$ |�nfkənt �mi�tiərəlɒd"k(ə)l �nfə |�meʃ(ə)n/ noun aweather advisory concerning weatherconditions important to the safety of allaircraft, such as severe or extreme tur-bulence. Abbreviation SIGMETsignificant pointssignificant points /�s$nfkənt�pɔnts/ plural noun geographical posi-tions used in air navigation, which aredefined by latitude and longitude andhave names consisting of five letterssignificant weather chartsignificant weather chart /s$ |

�nfkənt �weðə �tʃɑ�t/ noun a weatherchart with important weather informa-tion marked on itsignifysignify /�s$nfa/ verb to indicate, tosuggest, to mean � Buffet signifies theapproach of a stall. (NOTE: signifies –signifying – signified)silencesilence /�saləns/ noun the absence ofsound � total silence the completeabsence of sound � verb to stop, or stopsomething, making a noise � When anengine fire warning is received on theflight deck, the first action should be tosilence the warning bell.silencersilencer /�salənsə/ noun a device toreduce noise � In order to reduce thelevel of noise from the blower, silencersare incorporated in the main supplyducting.similarsimilar /�smlə/ adjective nearly thesame � Turbo-shaft engines are similarto turboprop engines.similaritysimilarity /�sm |�l�rti/ noun the factof having features that are nearly thesame � There are points of differenceand similarity between the two aircraft.simplesimple /�smpəl/ adjective 1. basic,not complex � A simple fuel system con-sists of a gravity feed tank, a filter, ashut-off valve and pipes. 2. easy � asimple questionsimplicitysimplicity /sm |�plsti/ noun thequality of having a basic, uncompli-cated design or concept � Because of itslightness, cheapness and simplicity, afixed pitch propeller is often fitted tosingle-engine aircraft.simplifysimplify /�smplfa/ verb to makeeasy, to make less complex or compli-cated � Repair procedures are being

further simplified by increasing use ofcold setting resins.simulate

simulate /�smjυlet/ verb to imitatethe conditions or behaviour of some-thing � The computer program simu-lates the action of an aircraft.simulated instrument flight

simulated instrument flight/�smjυletd �nstrυmənt �flat/ nounan instrument flight carried out in a sim-ulator on the ground or in a speciallyprepared aircraft with screens on thewindowssimulationsimulation /�smjυ|�leʃ(ə)n/ noun animitation of a real situation, createdoften for training purposes � a simula-tion of an engine fire � The computeranimation showed a simulation of theevents which followed the explosion onboard the aircraft.simulatorsimulator /�smjυletə/ noun amachine that is constructed to look likean aircraft cockpit with a full set ofinstruments, in which people can betrained to fly a particular type of aircraftsimultaneous

simultaneous /�sm(ə)l|�teniəs/adjective happening at the same time �

Most aircraft are now fitted with remotemagnetic indicator displays which canbe selected to show two simultaneousbearings from different radio navaids.sinesine /san/ noun a trigonometric func-tion defined as the length of the sideopposite to an angle in a right-angledtriangle divided by the length of thehypotenuse. Abbreviation sinsinglesingle /�sŋ$(ə)l/ adjective one onlysingle-engined aircraft

single-engined aircraft /�sŋ$(ə)l�end"n �eəkrɑ�ft/, single-engine air-craft noun an aircraft with one engineonlysink

sink /sŋk/ noun a downdraught of air� rate of sink the rate of descent of aglider � In order to achieve a safe land-ing, a glider has to be controlled so thatit makes contact with the runwaysmoothly at a very low rate of sink. �

verb to move downwards as in a fluid �If water enters the fuel tank, it will sinkto the bottom of the tank where it can bedrained off.sit

sit /st/ verb to be resting with yourbehind on a seat such as a chair � The


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pilot sits in the cockpit. (NOTE: sitting –sat)sitesite /sat/ noun a selected area of land� landing site � verb to position or toput in a particular place � Where it isimpossible or inadvisable to site thelocaliser antenna on the runway cen-treline, it may be positioned to one side.sittingsitting /�stŋ/ adjective � sitting posi-tion the position of a person who is ona seat � The correct technique of usingthe escape slides is to assume a sittingposition.situatesituate /�stʃuet/ verb to put in a par-ticular place, to locate � The inlet pres-sure is sensed by a single pitot-typeprobe which is situated just in front ofthe compressor.situationsituation /�stʃu |�eʃ(ə)n/ noun 1. alocation, the place where something is �The situation of the flight controls isimportant. 2. the conditions or circum-stances in a particular place or at a par-ticular time � The synoptic chart is agraphical representation of the generalweather situation over a given area at agiven time.six character groupsix character group /�sks�k�rktə �$ru�p/ noun a group of sixletters and/or numberssix degrees of freedom of motionsix degrees of freedom ofmotion /�sks d|�$ri�z əv �fri�dəm əv�məυʃ(ə)n/ plural noun the six types ofmovement that an aircraft must be ableto make: forward, upward and down-ward, and roll, yaw and pitchsizesize /saz/ noun the extent of a thing,how big something is � Whether or notan object can be seen by aircrew at agiven distance will depend on factorssuch as the size, shape and colour of theobject.skidskid /skd/ noun 1. a slide on slipperyground � Anti-skid braking systemsunits are designed to prevent the brakeslocking the wheels during landing, thusreducing the possibility of wheel skid. 2.a condition of uncoordinated flight thenthe aircraft moves away from the centreof a turn � Deflection of the ball in theturn coordinator indicates a slip or askid. � anti-skid (NOTE: To correct askid, the pilot should increase the bank,

or increase rudder pressure on thesame side as the ball has moved to inthe turn coordinator.) � verb 1. to slideon slippery ground � If you brake toohard on a wet surface, you might skid.(NOTE: skidding – skidded) � to skidto a halt to slide or skid until you stop2. to move sideways towards the outsideof a turning manoeuvreskillskill /skl/ noun expertise, an excellentability in something � Skill in accurateflying can only be achieved by constantpractice.skinskin /skn/ noun the outer layer of abody, or the outer layer of an aircraft �

The aircraft skin is riveted to stringersand frames.skip distance

skip distance /�skp �dstəns/ nounthe shortest distance at which a skywave can be received � The higher thelayer in which a direct wave signal istotally refracted and returns as a skywave, the greater the skip distance.skiplaneskiplane /�ski�plen/ noun an aircraftequipped with skis for taking off fromand landing on snowsky

sky /ska/ noun the atmosphere andouter space as seen from the earth � Thehigher the sun is in the sky, the moreintense is the radiation per unit area.skyjackskyjack /�skad"�k/ verb to use forceto take illegal control of an aircraft,especially a commercial aircraft, whenit is in the airsky wavesky wave /�ska wev/ noun part of aradiated wave which is returned toEarth by refraction from the ionosphereskyway

skyway /�skawe/ noun a route usedby aircraftskywriting

skywriting /�skaratŋ/ noun 1. theuse of an aircraft releasing colouredsmoke to form letters in the sky 2. let-ters or a message formed in the sky bycoloured smoke released from an air-craftslackslack /sl�k/ adjective 1. not tight � aslack cable a loose cable 2. not busy �

Early afternoon is a slack period of theday. 3. widely spaced � Throughout thetropics and sub-tropics, where pressuregradients are normally slack, the seabreeze is a regular feature. � Land and


211 smoke alarm

sea breezes occur in coastal areas whenthere is a slack pressure gradient.slantslant /slɑ�nt/ noun a slope or inclina-tion � Distance Measuring Equipment(DME) is a radio aid which measuresaircraft slant range to a ground beacon.� verb to slope � The wing slantsupwards from the root to the tip.slatslat /sl�t/ noun a movable device onthe leading edge of a wing which, whenextended, creates a gap that allows air topass smoothly over the top of the wingthus reducing the possibility of a stall �

The Socata Rallye is one of the few lightaircraft with leading edge slats.sleetsleet /sli�t/ noun 1. melting snow or amixture of rain and snow fallingtogether 2. US frozen rain in the form ofclear drops of ice or glaze ice coveringsurface objects (NOTE: Care should betaken to avoid any ambiguity.) � verb tofall in the form of sleet � It is sleeting.slideslide /slad/ noun a device whichallows continuous movement over asmooth surface � verb to move continu-ously over a smooth surface � Shearstress is the stress that resists the forcetending to cause one layer of a materialto slide over an adjacent layer. (NOTE:sliding – slid)slide raftslide raft /�slad rɑ�ft/ noun anescape slide which, when detachedfrom the aircraft, can be used as a life-raftslide ruleslide rule /�slad ru�l/ noun a gradu-ated device with sliding parts for per-forming complex mathematical opera-tionsslightslight /slat/ adjective small, minor �a slight increase a small increase � aslight drop in temperature a smalldecrease in temperatureslipslip /slp/ noun a condition of uncoor-dinated flight when the aircraft movestowards the inside of a turn � Slip isindicated by deflection of the ball in theturn and slip indicator. � verb to movesideways towards the inside of a turningmanoeuvre as a result of excessive bank(NOTE: slipping – slipped)

COMMENT: To correct a slip, the pilotshould decrease the bank, or increaserudder pressure on the same side as

the deflected ball in the turncoordinator. Slips are often used inaircraft with no flaps to increase therate of descent without increasing theairspeed.

slipperyslippery /�slp(ə)ri/ adjective which isdifficult to grip firmly because of wet-ness, smoothness, etc. � a slippery sur-face such as a wet or snow-covered run-wayslipringslipring /�slprŋ/ a metal ring in agenerator to which current is deliveredby the brushesslipstreamslipstream /�slpstri�m/ noun theflow of air sent backwards by an air-craft’s propellerslopeslope /sləυp/ noun 1. a slanting sur-face or slanting piece of ground, anincline � A slope of the runway mayincrease or decrease the take-off andlanding runs. 2. a state in which one endof an aircraft is higher than the other �

verb to be inclined, to be at an angle �

When the runway slopes upwards, awayfrom the aircraft, the approach mayappear to be higher than it actually is.slotslot /slɒt/ noun 1. a groove or channelinto which something can be fitted �

The float engages with a slot cut in thetube, so that, as the fuel level changes,the float moves up and down. 2. the par-ticular time at which an aircraft isscheduled to depart � Flight GF 506missed its slot and will have to wait 45minutes for another.smsm abbreviation statute milesmogsmog /smɒ$/ noun a mixture ofsmoke and fog � Smog is now rarebecause of pollution control.smokesmoke /sməυk/ noun a white, grey orblack product formed of small particlesgiven off by something which is burn-ing � The weather associated with visi-bility reductions by particles suspendedin the atmosphere is classified either asfog, mist, haze or smoke. � verb 1. togive off smoke � Somebody noticed thatone of the engines was smoking. 2. tobreathe in smoke from a cigarette, cigar,etc. � Passengers are not allowed tosmoke in the toilets.smoke alarmsmoke alarm /�sməυk ə |�lɑ�m/ nouna warning system that will ring or light


smoking 212

up if there is smoke somewhere � Wash-rooms are fitted with smoke alarms.smokingsmoking /�sməυkŋ/ noun the act ofbreathing in smoke from a cigarette,cigar, etc. � the airline has a no-smok-ing policy the airline does not allowpassengers to smoke during a flightsmoothsmooth /smu�ð/ adjective 1. even andwithout lumps or dents � a smooth sur-face 2. not rough or turbulent � Highground will disturb the smooth, hori-zontal flow of air. Opposite rough � asmooth running engine an enginewhich is operating wellSMRSMR abbreviation surface movementradarsnap rollsnap roll /�sn�p rəυl/ noun amanoeuvre in which an aircraft turns acomplete circle longitudinally whilemaintaining altitude and direction offlightsnowsnow /snəυ/ noun atmospheric watervapour frozen into ice crystals and fall-ing to Earth as white flakes � Snowcover tends to persist on north-facingslopes of mountainous regions after ithas melted on south-facing slopes.snowfallsnowfall /�snəυfɔ�l/ noun a quantityof snow which comes down at any onetime � a heavy snowfallsnowflakesnowflake /�snəυflek/ noun a smallpiece of snow formed from a number ofice crystals � The size of a snowflakedepends on the temperature.snow ploughsnow plough /�snəυ plaυ/ noun avehicle built to push the snow fromroads, tarmac, etc.snowstormsnowstorm /�snəυstɔ�m/ noun aheavy fall of snow accompanied bywind � The airport is closed because ofthe snowstorm.softsoft /sɒft/ adjective not hard � Ther-moplastic materials become soft whenheated.softensoften /�sɒf(ə)n/ verb to make soft �

Thermoplastic materials are softenedby many aircraft fluids.solarsolar /�səυlə/ adjective referring to thesunsolar-poweredsolar-powered /�səυlə �paυəd/adjective powered by energy derivedfrom the suns rays

‘…a 210–240-foot wingspan solar-powered aircraft for flight at 100,000 feet,is being designed in California’ [Pilot]

solar radiationsolar radiation /�səυlə �redi |

�eʃ(ə)n/ noun the total electromagneticradiation given off by the sunsolar systemsolar system /�səυlə �sstəm/ nounthe sun and the planets governed by thesunsolesole /səυl/ adjective only � the solesurvivor of the air crashsolenoidsolenoid /�sɒlənɔd/ noun a cylindri-cal coil of wire acting as a magnet whencarrying electric current � Fuel ismetered from the aircraft fuel system bya solenoid-operated control valve.solidsolid /�sɒld/ adjective 1. referring tosomething which is not liquid or gase-ous � Visibility is reduced by the pres-ence of solid particles such as dust orsand in the atmosphere. 2. � solid lineunbroken line � noun a substance whichis not a liquid or a gas � Ice is a solid,water is a liquid and vapour is a gas.solid-statesolid-state /�sɒld stet/ adjectivereferring to semiconductor devicessolid-state devicesolid-state device /�sɒld stet d |

�vas/ noun an electronic device thatoperates by using the effects of electri-cal or magnetic signals in a solid semi-conductor materialsolid-state technologysolid-state technology /�sɒldstet tek|�nɒləd"i/ noun technologyusing the electronic properties of solidsto replace those of valvessolosolo /�səυləυ/ adverb done by one per-son alone � to go solo or to fly solo � Heflew solo across the Atlantic.solutionsolution /sə |�lu�ʃ(ə)n/ noun 1. ananswer to or means of solving a prob-lem or difficulty � The navigation com-puter or slide rule is suitable for thesolution of many different types ofmathematical problem. 2. a liquid madeby dissolving a solid or gas in water orsome other fluid � Spillage from a leadacid battery may be neutralised bywashing with a dilute solution ofsodium bicarbonate.solvesolve /sɒlv/ verb to find the answer to,or a way of removing, a difficulty orproblem � The triangle of velocities isused to solve navigation problems.


213 south-westsomewhatsomewhat /�s�mwɒt/ adverb tosome extent, a bit � The usefulness ofpure aluminium as a structural materialis somewhat limited.sonicsonic /�sɒnk/ adjective 1. referring tosound 2. within the human hearingrange � sonic speed the speed of soundsonic boomsonic boom /�sɒnk �bu�m/ noun anoise, due to shock waves, producedwhen an aircraft travels through the airfaster than the speed of soundsophisticatedsophisticated /sə |�fstketd/adjective highly developed and com-plex � The electronic flight instrumentsystem, commonly known as EFIS, is ahighly sophisticated type of flight direc-tor system. � The A340 is a sophisti-cated aeroplane.sortiesortie /�sɔ�ti/ noun an operationalflight by one aircraft � The test pro-gramme has accumulated 1,146 sorties.soundsound /saυnd/ adjective strong � Astressed skin structure is used on mod-ern aircraft which gives a sound struc-ture with relatively low weight. � nounsomething that can be heard and iscaused by vibration of the surroundingair � FM (frequency modulation) givesa wide range of sounds or a very highdata rate. � verb 1. to make a noise � Ifthe trim position is incorrect, a warninghorn will sound when number threethrust lever is advanced for take off. �

sonic 2. to seem � It sounds as if thepilot is having trouble.sourcesource /sɔ�s/ noun a supply � Underemergency conditions, the battery maybe the only source of electrical power. �Jet aircraft have a ready source of com-pressed air from the compressor sec-tions of their engines.southsouth /saυθ/ noun a compass point onthe mariner’s compass 180° clockwisefrom due north and directly oppositenorth � Fly towards the south. � southfacing mountain side the face of amountain which looks towards thesouth � adjective 1. referring to areas orregions lying in the south, referring tothe compass point 180° from north � thesouth side of the river 2. the southernpart of a region or country � SouthAmerica � South Dakota � adverb

towards the south � The aircraft is fly-ing south.southboundsouthbound /�saυθbaυnd/ adjectivetravelling towards the south � a south-bound flightsouth-eastsouth-east /�saυθ �i�st/ noun thedirection between south and east � aregion in the south-east of Canada �

adjective 1. situated in the south-east �

the south-east coast of England 2.blowing from or coming from thesouth-east � adverb towards the south-east � We were heading south-east.south-easterlysouth-easterly /�saυθ �i�stəli/adjective 1. blowing from or comingfrom the south-east � a south-easterlywind 2. moving towards the south-east� We were following a south-easterlydirection.south-easternsouth-eastern /�saυθ �i�stən/ adjec-tive referring to or situated in the south-east � the south-eastern coast of Spainsoutherlysoutherly /�s�ðəli/ adjective 1. situ-ated towards the south � the most south-erly point of a country 2. coming fromthe south � A southerly wind was blow-ing. 3. moving to or towards the south �We were flying in a southerly direction.� noun a wind which blows from thesouthsouthern

southern /�s�ð(ə)n/ adjective situ-ated in the south � the southern hemi-sphere � the southern Atlanticsouthern hemispheresouthern hemisphere /�s�ð(ə)n�hemsfə/ noun the area of the Earth tothe south of the equatorSouth PoleSouth Pole /�saυθ �pəυl/ noun thepoint which is furthest south on theearth � to fly over the South Polesouthwardsouthward /�saυθwəd/ adjectivegoing towards the south � to go in asouthward direction � adverb US sameas southwardssouthwardssouthwards /�saυθwədz/ adverbtowards the south � The aircraft was fly-ing southwards.south-westsouth-west /�saυθ �west/ noun thedirection between south and west � aregion in the south-west of France �

adjective 1. situated in the south-west �the south-west tip of England 2. blow-ing from or coming from the south-west


south-westerly 214

� adverb towards the south-west � Wewere heading south-west.south-westerly

south-westerly /�saυθ �westəli/adjective 1. blowing from or comingfrom the south-west � a south-westerlywind 2. moving towards the south-west� We were following a south-westerlydirection.south-westernsouth-western /�saυθ �westən/adjective referring to or situated in thesouth-west � The south-western cornerof England includes Cornwall andDevon.south wind

south wind /�saυθ �wnd/ noun awind blowing from or coming from thesouth (NOTE: A wind is named after thedirection it comes from.)space

space /spes/ noun 1. an empty area �A major problem with fuel storage isfinding space within the airframe. 2. thephysical universe outside the Earth’satmosphere � VHF (very high fre-quency) waves tend to pass through thelayers of the ionosphere into space.span

span /sp�n/ noun the distancebetween two pointsspar

spar /spɑ�/ noun the main longitudinalbeam of an aircraft wing � Designing awing skin, a rib or a spar as a single bigitem rather than assembling it frommany smaller components minimisesthe number of structural parts.sparkspark /spɑ�k/ noun a light producedby a sudden electrical discharge � verbto suddenly start a process or action �

Crew must quickly establish control toensure panic does not spark a prema-ture evacuation.spark plug

spark plug /�spɑ�k pl�$/, sparkingplug /�spɑ�kŋ �pl�$/ noun a devicescrewed into each cylinder head inspark ignition engines, which initiatesfuel combustion by an electric spark. �

air gap. Also called sparking plugspatspat /sp�t/ noun a streamlined cover-ing for a wheel fitted on a light aircraftto reduce drag. Also called wheel fair-ingspatial disorientation

spatial disorientation noun a situ-ation of bad visibility and/or unusualmanoeuvres which result in the pilot notknowing what attitude the aircraft is in

speaker

speaker /�spi�kə/ noun � loud-speakerspecialspecial /�speʃ(ə)l/ adjective particu-lar, specific, or not ordinary � To makea composite, it is necessary to combinethe reinforcing glass fibres with someform of special glue. � noun a specialmeteorological reportspecial aerodrome reportspecial aerodrome report/�speʃ(ə)l �eərədrəυm r|�pɔ�t/ nounreport used if there are significantweather changes since the last meteoro-logical aerodrome report. AbbreviationSARspecial VFR flightspecial VFR flight noun a control-led VFR flight permitted by air trafficcontrol to fly within a control zone inmeteorological conditions below visualmeteorological conditionsspecific

specific /spə |�sfk/ adjective clearlydefined and definite � Flight levels arespecific pressure altitudes. � The air-frame has to be built to very specificrequirements.specification

specification /�spesf |�keʃ(ə)n/noun a detailed description that sets outwhat something consists of, what isneeded, what is involved, etc. � Fluidsare coloured for recognition purposesand fluids of different specificationsmust never be mixed.specific gravity

specific gravity /spə|�sfk�$r�vti/ noun the density of a sub-stance compared with that of water,which is 1.00 (NOTE: This is the oldname for relative density.)specify

specify /�spesfa/ verb to name indetail � The minimum values for deci-sion heights are specified by thenational licensing authorities for vari-ous types of aircraft and for various air-ports. � Pressure must be maintainedwithin specified limits during all phasesof flight.specimen

specimen /�spesmn/ noun a parttaken as an example of the whole � Bytesting specimen structures and compo-nents to destruction a safe life can beassessed for all such structures andcomponents.speed

speed /spi�d/ noun the rate of motionover a distance in time


215 spoolsphere

sphere /sfə/ noun an object in theshape of a ball � The Earth is not a per-fect sphere. � A circle drawn on the sur-face of a sphere, whose plane passesthrough the centre of the sphere iscalled a great circle.spherical

spherical /�sferk(ə)l/ adjectiveshaped like a sphere � The Earth isalmost spherical in shape. � Draincocks are generally simple, manuallyoperated spherical valves.spill

spill /spl/ noun the running out of aliquid from a container, especially whenit is unintentional � an oil spill � a fuelspill � verb to cause liquid to run out ofa container, usually unintentionally � Iffuel is spilt, it creates a fire hazard.(NOTE: spilling – spilled or spilt)spillage

spillage /�spld"/ noun the spilling ofa liquid � Any fuel spillage must becleaned up immediately. (NOTE: Theword spillage is used in a more generalsense than the word spill.)spin

spin /spn/ noun 1. fast rotation � thespin axis of the earth 2. the continuedspiral descent of an aircraft where theangle of attack of one wing is greaterthan the stalling angle � verb 1. to rotaterapidly � The Earth is spinning on itsaxis. 2. to put an aircraft into a contin-ued spiral descent with the angle ofattack of the mainplane greater than thestalling angle � It is prohibited to spingeneral-purpose light aircraft whichare not equipped with a suitable har-ness.

COMMENT: The Moroccan aerobaticteam ‘La Marche Verte’ perform aformation manoeuvre with threeaircraft spinning through multiplerotations while inverted.

spindle

spindle /�spnd(ə)l/ noun a pin or barwhich rotates or on which somethingrotates � A cup anemometer has threecups, mounted on a spindle, that aredriven by the wind causing the spindleto rotate.spine

spine /span/ noun the longitudinalcentral part of an engine � Annularinner and outer air casings form a tun-nel around the spine of the engine.

spinnerspinner /�spnə/ noun a cap that fitsover the hub of the propeller of an air-craftspiralspiral /�sparəl/ adjective windingcontinuously in circles as it ascends ordescendsspiral divespiral dive /�sparəl �dav/ noun adangerous uncontrolled turning descentof an aircraft in which rate of descentand speed increasesplinespline /splan/ noun a groove in ashaft for meshing or engaging withanother componentsplitsplit /splt/ noun 1. a division 2. abreak along a line, especially in wood,plastic or rubber � a split in a tyre � verb1. to divide � Retractable undercar-riages can be split into three groups. 2.to break along a line � One of the tyressplit on impact. (NOTE: splitting – split)� adjective divided or broken along alinesplit bus systemsplit bus system /�splt �b�s�sstəm/ noun an electrical system inwhich there are two separate powergeneration systems � The parallel sys-tem and the split bus system are bothused to distribute electrical power.spoilerspoiler /�spɔlə/ noun a hinged sur-face on the upper wing which, whenopened, decreases lift and increasesdrag � If a problem occurs in the spoilersystem a master caution light illumi-nates.

COMMENT: Spoilers are sometimescalled ‘speed brakes’. They are usedduring the descent prior to landing andimmediately after landing to decreaselift and increase braking effect.

sponsonsponson /�spɒnsən/ noun an air-filled structure or small wing projectingfrom the lower hull of a seaplane tokeep it steady on waterspontaneousspontaneous /spɒn |�teniəs/ adjec-tive happening without external cause �Spontaneous ignition may occur if oxy-gen is allowed to come into contact withoil or grease.spoolspool /spu�l/ noun one completeaxial-compressor rotor � The singlespool compressor consists of one rotorassembly and stators. � verb � to spooldown to allow the revolutions of a tur-


spot 216

bofan engine to decrease � to spool upto increase the revolutions per minute ofa turbofan enginespotspot /spɒt/ noun 1. a special or smallplace � Charts should be kept in a con-venient spot in the cockpit. 2. a smallroundish mark or piece � a spot of oil ona shirt � spot height the height of a par-ticular place, e.g. a mountain peak,marked on a chartspotlightspotlight /�spɒtlat/ noun a powerful,often moveable light which illuminatesa small area � A spotlight is mounted onthe roof.sprayspray /spre/ noun 1. a body of liquidin fine drops � The generator is cooledby oil spray delivered by the constantspeed drive section. 2. a container thatsends out liquid in fine drops � verb toapply or to send out liquid in the form offine drops � Some engines have thecoolant sprayed directly into the com-pressor inlet, but for axial flow com-pressor engines, it is more suitable tospray the coolant into the combustionchamber inlet.spreadspread /spred/ noun an extension ofthe area covered or affected by some-thing � Measures are taken to preventthe spread of fire. � verb to extend thearea of something � Strong jets of watershould not be used on a liquid fire asthis may cause the fire to spread. � Thesystem sprays a quantity of fluid ontothe windscreen, which is then spread bythe wipers. (NOTE: spreading –spread)springspring /sprŋ/ noun 1. a metal devicewhich, when under tension, tries toresume its previous position � The pitchlock piston is held in the forward posi-tion by a spring. 2. the season betweenwinter and summersquallsquall /skwɔ�l/ noun a suddenincrease in wind speed lasting for sev-eral minutes � Surface squalls are dueto the spreading out of strong downdraughts at the surface. � Even with alight mean wind speed, squalls of 50 kt(knots) or more can occur with suddenchanges in direction.squaresquare /skweə/ noun a shape with 4equal sides and 4 right angles � adjec-

tive shaped like a square � a squarepanelsquare footsquare foot /�skweə �fυt/ noun aunit of measurement of area, which isone foot long by one foot widesquare metresquare metre /�skweə �mi�tə/ nouna unit of measurement of area, which isone metre long by one metre wide � Theroom is 5m x 9m so the area is 45 squaremetres (45m2).square rootsquare root /�skweə �ru�t/ noundivider of a quantity that, when multi-plied by itself, gives the quantity � 3 isthe square root of 9.squawksquawk /skwɔ�k/ noun an identifica-tion code. � transponder � verb to acti-vate specific modes, codes or functionson a transponder � Garbling occurswhen two signals are received simulta-neously and can be resolved either tech-nically or by making one of the aircraftsquawk.squeezesqueeze /skwi�z/ verb to press hardfrom opposite directions � Static seals,gaskets and packing are used in manylocations, and these effect a seal bybeing squeezed between two surfaces.SRSR abbreviation sunriseSSSS abbreviation sunsetSSRSSR abbreviation secondary surveil-lance radarstabilisestabilise /�stebəlaz/, stabilize verbto become steady and unchanging �

After the engine has been started,engine speed is increased to 1,000r.p.m. (revolutions per minute) until cyl-inder head and oil temperatures havestabilised at normal operating tempera-tures.stabiliserstabiliser /�steblazə/, stabilizernoun a device to improve the tendencyof an aircraft to return to its originalattitude after being deflected

COMMENT: Some aircraft have an all-moving tailplane called a ‘stabilator’ (acombination of the words stabiliserand elevator).

stabilitatorstabilitator /stə |�bltetə/ noun �

stabiliserstabilitystability /stə |�blti/ noun 1. being sta-ble or steady � The stability of the Ces-sna 150 makes it an ideal training air-


217 stall warning system

craft. 2. a state of the atmosphere inwhich air will resist vertical displace-ment � When air moves away from itssource region, the stability of the loweratmosphere changes.

COMMENT: Stability can be classifiedas three types. Positive stability isthe tendency of a body to return to itsoriginal state after being displaced.Light training aircraft have positivestability. Neutral stability is thetendency of a body to remain in thenew position after displacement.Negative stability is the tendency of abody to continue moving away from itsoriginal position after displacement.

stability augmentation systemstability augmentation system/stə |�blti �ɔ�$mən |�teʃ(ə)n �sstəm/noun a flight control system whichautomatically adjusts pitch and yaw toimprove an aircraft’s stability. Abbrevi-ation SASstablestable /�steb(ə)l/ adjective 1. steady2. referring to an atmosphere in whichthere is little or no vertical movement �

Layer cloud occurs in a stable atmos-phere.stack

stack /st�k/ verb 1. to put one on topof the other � By stacking rows of hori-zontal dipoles one above the other, awell-defined electronic glide path canbe transmitted. 2. to keep aircraft cir-cling at different heights while they arewaiting to land at an airport � noun anumber of aircraft waiting to land at anairport that are circling at differentheightsstackedstacked /st�kt/ adjective circling atdifferent heights prior to landingstackupstackup /�st�k�p/ noun same asstackstage

stage /sted"/ noun 1. one of severalsections, steps, or levels into which aprocess can be divided � There are threestages in the life cycle of a thunder-storm: process of formation, develop-ment and decay. � Calculate headingsto steer for each stage of the flight. �cruise stage of the flight the section ofa flight between top of climb after take-off and start of descent to land � at alater stage at a later time 2. a groupcomponents forming part of an electri-cal or electronic system � In the axial

flow compressor, many stages of mov-ing and stationary blades are needed,each row of rotors and a row of statorsforming a stage.stagger

stagger /�st�$ə/ noun a design inwhich the leading edge of one wing of abiplane projects beyond that of theother wing � verb to make the leadingedge of one wing of a biplane projectbeyond the leading edge of the otherwingstall

stall /stɔ�l/ noun 1. a loss of lift causedby the breakdown of airflow over thewing when the angle of attack passes acritical point � In some configurations itis possible for the buffet speed to be lessthan the required 7% margin ahead ofthe stall. 2. a situation in which anengine or machine stops suddenlybecause an opposing force overcomesits driving power � Compressor stallcan be caused by ice formation in theair intake. � recovery � verb to lose liftby the breakdown of airflow over thewing when the angle of attack passes acritical point � Many light aircraft stallwhen the angle of attack exceeds 15°. �

recover

COMMENT: A stall has nothing to dowith the engine stopping. An aircraftcan stall at any airspeed and in anyattitude.

stalling angle

stalling angle /�stɔ�lŋ ��ŋ$(ə)l/noun the angle relative to the horizontalat which the flow of air around an aero-foil changes abruptly, resulting in sig-nificant changes in the lift and drag ofan aircraftstalling speed

stalling speed /�stɔ�lŋ spi�d/ nounthe speed at which the angle of attack issuch that lift over the wing surfacebreaks down

COMMENT: Traditionally, an aircraftcan stall at any airspeed, providing theangle of attack is great enough.Stalling speed is often used to refer tothe speed below which the aircraftcannot remain airborne.

stall warning system

stall warning system /�stɔ�l�wɔ�nŋ �sstəm/ noun a system towarn the pilot that the aircraft is aboutto stall


standard 218standardstandard /�st�ndəd/ noun some-thing, e.g. a quality or measure, that isofficially recognised as an example thatothers must conform with � Water is thestandard for determining relative den-sity. � a high standard of skill a highlevel of skill � adjective normal, offi-cially or generally accepted � standardprocedure normal procedurestandard atmospherestandard atmosphere /�st�ndəd��tməsfə/ noun a unit of pressuredefined as the pressure that will supporta 760 mm column of mercury at 0°C atsea level, equal to 1.01325 x 105 new-tons per square metrestandard instrument departurestandard instrument departure/�st�ndən �nstrυmənt d|�pɑ�tʃə/noun a published navigational chartshowing the route an aircraft must takeas it takes off and climbs away from anairport. Abbreviation SIDstandard parallelsstandard parallels /�st�ndəd�p�rəlelz/ plural noun (in a conical pro-jection) the parallels of latitude wherethe cone cuts the surfacestandard pressure settingstandard pressure setting/�st�ndəd �preʃə �setŋ/ noun 1013.25millibars. Abbreviation SPSstandard rate turnstandard rate turn /�st�ndəd ret�t%�n/ noun a turn made at a precisenumber of compass degrees per second

COMMENT: Rate 1 turn = 180 ° in 1minute, Rate 2 turn = 360 ° in 1 minute,Rate 3 turn = 540 ° in 1 minute, Rate 4turn = 720 ° in 1 minute. Standard rateturns are made using particular anglesof bank for specific airspeeds and areused while flying under InstrumentFlight Rules (IFR). The pilot can makeaccurate turns to given headings bybanking at the standard rate andtiming the turn.

standard timestandard time /�st�ndəd tam/noun a universally adopted time for allcountries based on zone timestandbystandby /�st�ndba/ adjective sec-ondary, able to be used as a back-up �

Some aircraft use a ram air turbine thatcan be very useful as a standby powersource in the event of failure of a com-plete main AC (alternating current)generating system.standby ticketstandby ticket /�st�ndba �tkt/noun a cheaper air ticket bought just

before departure time � There are nostandby tickets to Montreal.standing agreement

standing agreement /�st�ndŋ ə |

�$ri�mənt/ noun an agreement betweencontrolling units in different flightinformation regions to allow the trans-fer of control from one sector to the nextwithout individual coordination, pro-vided agreed parameters are metstanding wavestanding wave /�st�ndŋ wev/noun the motion of air downwind of asteep hill or mountain in which the highand low points of the wave do not moveSTAR

STAR abbreviation standard arrivalroutestarboard

starboard /�stɑ�bəd/ noun, adjectivethe right-hand side of an aircraft whenfacing forwards when inside the aircraft� The angle between heading and trackof an aircraft is called drift and isexpressed in degrees to the port or star-board side of aircraft heading. Oppositeportstarterstarter /�stɑ�tə/ noun a device to startan enginestarter motor

starter motor /�stɑ�tə �məυtə/ nounin a piston engine, a small electricallyoperated device to turn the engine untilignition startsstart-up

start-up /�stɑ�t �p/ noun a procedureto start an engine � After start-up, theengine accelerates up to idling speed.statestate /stet/ noun the existing condi-tion of something � a state of equilib-rium � Ice in a liquid state is calledwater. � Water in a gaseous state isknown as vapour. � A logic gate is atwo-state device i.e. on/off. � in a poorstate in a bad condition � verb to say orto mention, or to give informationclearly � It states in the information thatyou must not open the can near a flame.� Please state your name and address.statementstatement /�stetmənt/ noun some-thing formally expressed in words �

After the crash, the president and chiefexecutive of the company made a briefstatement to the waiting news reporters.static

static /�st�tk/ adjective not acting,not changing, passive or not moving �

noun the background noise during radiotransmission


219 stewardstatic displaystatic display /�st�tk d |�sple/noun a display of parked aircraft on thegroundstatic electricity

static electricity /�st�tk �lek |

�trsti/ noun electricity not flowing asa current � When the aircraft travelsthrough the air, friction causes a chargeof static electricity to be built up on theairframe.static ground running

static ground running /�st�tk�$raυnd �r�nŋ/ noun the running ofthe engine while the aircraft is station-ary on the groundstatic line

static line /�st�tk �lan/ noun a ropeattached to an aircraft and a parachutethat automatically opens the parachutewhen the parachutist jumpsstatic port

static port /�st�tk pɔ�t/ noun asmall hole in the side of the aircraftwhich senses static pressure and is usedin the operation of the altimeter, verticalspeed indicator and airspeed indicator �Ensure that the static port is clear.static pressure

static pressure /�st�tk �preʃə/noun the pressure of a fluid acting onand moving with a bodystationstation /�steʃ(ə)n/ noun 1. a particu-lar assigned location � The interphonesystem allows the flight deck to commu-nicate with cabin crew stations. 2. thelocation of a radio transmitter � a VORstationstationarystationary /�steʃ(ə)n(ə)ri/ adjectivenot moving � The aircraft was station-ary on the ground with engine running.statorstator /�stetə/ noun a fixed part of arotary machine � The low-pressurecompressor has large rotor blades andstator blades and is designed to handlea far larger airflow than the other twocompressors. � A temperature probe isembedded into the stator of the genera-tor and a meter is provided, so that gen-erator stator temperature can be moni-tored.status

status /�stetəs/ noun condition � Thecentre-zero ammeter tells the pilot thestatus of the aircraft battery.statute milestatute mile /�st�tʃu�t mal/ noun anon-SI unit of length equalling 1.609kilometres � It is 20 statute miles to theairport. Abbreviation sm

STCSTC abbreviation supplemental typecertificateSTCASTCA abbreviation short-term conflictalertsteadysteady /�stedi/ adjective constant andunchanging � The manual test will givea steady red light. � a steady wind awind of constant speed and directionsteam fogsteam fog /�sti�m fɒ$/ noun fogformed when cold air moves over rela-tively warm water � Visibility wasimpaired because of steam fog.steelsteel /sti�l/ noun a metal alloy of iron,carbon and other compounds � stain-less steel steel containing chromiumand nickel that is highly resistant to cor-rosion � Tubing in parts of the systemcontaining fluid at high pressure areusually made from stainless steel.steepsteep /sti�p/ adjective 1. slopingsharply � a steep angle of approachthe angle formed by the aircraftapproach flight path and the horizontalis greater than usual 2. closely spaced 3.referring to marked changes in pressureor temperature in a relatively short hor-izontal distance � Cooling of the air incontact with the ground at night cancause a very steep inversion of temper-ature at the surface. � Pressure gradi-ents in anti-cyclonic curvature tend notto be steep.steersteer /stə/ verb to direct by using awheel or control stick � The aircraft issteered on the ground by using the rud-der pedals.steeringsteering /�stərŋ/ noun 1. guiding ordirecting � Steering is controlled byrudder pedals. 2. a system for guidingor directing a car, aircraft, etc. � Mostmodern light aircraft have nose-wheelsteering but older tail-draggers aresteered on the ground by using differen-tial braking.stepstep /step/ noun 1. a stage � The firststep in map reading is to orientate thechart. 2. one stair � Mind the step!stewardsteward /�stju�əd/ noun a male mem-ber of airline staff who look after pas-sengers during the flight. � cabin crew,flight attendant, stewardess (NOTE:Different airlines use different terminol-ogy for their staff.)


stewardess 220stewardessstewardess /�stju�ə|�des/ noun afemale member of airline staff who lookafter passengers during the flight. �

cabin crew, flight attendant, steward(NOTE: Different airlines use differentterminology for their staff.)stickstick /stk/ noun the main hand con-trol used by the pilot to control the air-craft roll and pitch � Using fly-by-wiretechnology, the stalling angle cannot beexceeded regardless of stick input. �

verb to become fixed, as if with glue �

Ice crystals and snowflakes do not stickto airframes, and so icing is a problemonly when super-cooled water dropletsare present.stiffstiff /stf/ adjective 1. rigid or inflexi-ble � Kevlar 49 is stiffer than glass, butonly about half as stiff as carbon fibres.2. not easily bent or turned � controlsurfaces may become stiff as a resultof icing control surfaces may becomedifficult to move 3. � a stiff wind afairly strong windstiffenstiffen /�stf(ə)n/ verb 1. to make rigidor inflexible, to make stiff � Beams canbe additionally stiffened in a downwarddirection by vertical and diagonalmembers. 2. to become strongerSTOLSTOL /stɒl/ noun 1. a flying systemthat allows an aircraft to take off andland on a very short runway 2. an air-craft fitted with the STOL system. Fullform short takeoff and landingstopstop /stɒp/ noun 1. the end of a move-ment � to come to a stop to stop mov-ing 2. a component which limits the dis-tance that a moving part can move � Anadjustable stop on the throttle controlensures a positive idling speed.storagestorage /�stɔ�rd"/ noun the act ofstoring something � A reservoir pro-vides storage space for the system fluid.storestore /stɔ�/ noun 1. a supply � Themaintenance section keeps a store ofspare components. 2. US a shop � verbto put away for future use � A capacitoris a device with the ability to temporar-ily store an electric charge.storesstores /stɔ�z/ plural noun goods �

Freight carrying aircraft have support-ing members of greater strength toallow for the carriage of heavy stores.

stormstorm /stɔ�m/ noun a violent weatherdisturbance with high winds and rain orsnow � Storms produced by daytimeheating are most frequently encoun-tered in the afternoon and earlyevening.stowstow /stəυ/ verb to place something inits correct position in the aircraft �

Make sure the fire-extinguisher isstowed.stowagestowage /�stəυd"/ noun a space forstowing things � A multi-wheel combi-nation has the advantage of smaller andlighter undercarriage structures, andwing stowage problems can be over-come by suitable mechanisms.stowawaystowaway /�stəυə|�we/ noun a per-son who travels secretly by hiding in anaircraft, or a ship, not paying the fare �

The crew must be alert at all times to thepossibility of hijacking, bombs andstowaways.strainstrain /stren/ noun deformationcaused by stressstrapstrap /str�p/ noun a long narrow stripof fabric with a buckle � verb � to strapin to fasten a seat or safety belt aroundsomebodystratocumulusstratocumulus /�str�təυ |

�kju�mjυləs/ noun a layer of smallcumulus clouds lower than altocumu-lus, i.e. below 3,000 m � Light rain mayfall occasionally from stratocumulus.stratospherestratosphere /�str�təsfə/ noun thelayer of the atmosphere which extendsfrom the tropopause to about 50 kmabove mean sea level � A cumulonimbuscloud may extend vertically, into thestratosphere.stratusstratus /�stretəs/ noun a low-altitudelayer cloud � Drizzle falls from shallowlayer cloud such as stratus.streamstream /stri�m/ noun a steady currentof a fluid � Thermocouple probes arepositioned in the gas stream, so as toobtain a good average temperaturereading.strengthstrength /streŋθ/ noun 1. the abilityof a material to take pressure or supporta load � Aircraft wheels require greatstrength and are constructed in twohalves which are bolted together afterthe tyre is fitted. � Magnesium does not


221 sub-beam

possess sufficient strength in its purestate for structural uses, but whenmixed with zinc, aluminium, and man-ganese it produces an alloy having thehighest strength-to-weight ratio of anyof the commonly used metals. � high-strength materials materials which arevery strong 2. the degree of clarity andvolume of a signal � A radio wave losesstrength as range increases. 3. thedegree of dilution of a liquid � Incorrectmixture strength may cause detonation.4. intensity of radiation � The strengthof the sun’s radiation varies with lati-tude. 5. the speed and force of a wind �

High ground will disturb the smoothhorizontal flow of air, with the degree ofdisturbance depending upon thestrength of the wind and the roughnessof the terrain.strengthenstrengthen /�streŋθ(ə)n/ verb tomake strong or stronger � Some alloysare hardened and strengthened by heattreatment. � the wind is strengtheningthe wind is increasing in speedstrengtheningstrengthening /�streŋθ(ə)nŋ/ noun1. the act of making stronger � Aircraftwhich require large apertures in thefuselage for freight doors, etc., needincreased strengthening around theseareas. 2. the fact of becoming stronger� strengthening of the windstressstress /stres/ noun 1. the load per unitarea to which a body that resists distor-tion or change of shape is subjected byinternal forces � Turbine blades in theaverage jet engine vibrate at frequen-cies of 1 million per minute, and in eachcycle experience stress. 2. a worried,anxious and tired state brought on e.g.by overwork � He gave stress as thereason for wanting a week off work. 3.emphasis � verb to emphasise � It mustbe stressed that the description is amodel and departures from it oftenoccur.stretchstretch /stretʃ/ noun a continuousunbroken length � a stretch of coast �

verb to extend or enlarge beyond theproper limits � Tensile stress or tensionis the resistance of a material to beingstretched.stretchingstretching /�stretʃŋ/ noun extend-ing or enlarging beyond the proper lim-

its � Tensile stress is the resistance topulling apart, or stretching, producedwhen two forces in opposition act alongthe same straight line.strictstrict /strkt/ adjective precise, exact� Fuels for aircraft must conform tostrict requirements. � All generatorvoltages, frequencies and their phasesequence must be within very strict lim-its to ensure proper system operation.strikestrike /strak/ noun an impact or col-lision � verb to hit (NOTE: striking –struck)stringerstringer /�strŋə/ noun a thin metal orwood strip which goes from one end ofthe fuselage to the other � Stringers aremade of a light alloy material.stripstrip /strp/ noun a long narrow piece,usually of the same width from end toend � a strip of paper � verb to disman-tle � After the collision, the engine wasstripped down to its component parts.strokestroke /strəυk/ noun any of a series ofmovements of a piston from one end ofthe limit of its movement to another �

The connecting rod links the piston tothe crankshaft and transmits the forceof the power stroke from the piston tothe crankshaft.structuralstructural /�str�ktʃ(ə)rəl/ adjectivereferring to the structure of somethingsuch as an aircraft � As laid down in theflight manual, the structural limitationsmust never be exceeded. � structuralfailure a breaking of part of the aircraftstructurestructurestructure /�str�ktʃə/ noun 1. some-thing constructed � Aircraft structureserves the same purpose for an aircraftas the skeleton for a human body. 2.frameworkstrutstrut /str�t/ noun a bar or rod used tostrengthen a structure against forcesfrom the side � A strut is designed towithstand compressive loads.stubstub /st�b/ noun a short rectangularextension � The plan-form of a militaryair traffic zone is in the shape of a circlewith a stub.sub-sub- /s�b/ prefix 1. of less importancein rank 2. belowsub-beamsub-beam /�s�b bi�m/ noun a lessimportant or minor beam � A lobe is one


subject 222

of two, four or more sub-beams thatform a directional radar beam.subjectsubject /�s�bd"kt/ noun a topic ormatter for discussion or study � Aknowledge and understanding of thesubject of ice accretion is essential inorder that the hazard can be minimised.subjectedsubjected /səb|�d"ektd/ adjective �subjected to affected by or made toexperience something � To maintain thepressure difference between two inter-nal engine sections, which are sub-jected to air pressures of different value,a multi-air seal is used. (NOTE: There isan important difference between sub-ject to and subjected to.)subject to

subject to /s�b |�d"ekt tu�/ adjectivelikely to be affected by, liable to � Theairspeed indicator is subject to error. �

Turbine engines are subject to icingduring flight through super-cooleddroplet cloud. � verb � to subject to tomake something or somebody experi-ence something, often somethingunpleasant � The aircraft was subjectedto rigorous tests.sublimatesublimate /�s�blmet/ verb to trans-form directly from the solid to the gase-ous state or from the gaseous to thesolid state without becoming a liquid �

For hoar frost to form on an aircraft theairframe temperature must be below0°C (Celsius), so that the surroundingair is cooled to below its dew point andwater vapour in contact with the air-craft skin is directly sublimated into icecrystals.sublimationsublimation /�s�bl|�meʃ(ə)n/ nountransformation directly from the solid tothe gaseous state or from the gaseous tothe solid state without becoming a liq-uid � In sub-zero conditions sublima-tion will occur when air is cooled belowthe frost point, producing a deposit ofice crystals.sub-scalesub-scale /�s�b skel/ noun a sec-ondary, not main, scale on an instru-ment � The barometric pressure is seton the sub-scale and the altimeter mainscale displays height or altitude.subsequentsubsequent /�s�bskwənt/ adjec-tive following in time or order � A struc-tural prototype is put through cycles of

stressing far more severe than can beexpected during the aircraft’s subse-quent operational life. � a subsequentoccasion a following occasionsubsidesubside /səb|�sad/ verb 1. to sink to alower level � Cool air subsides. 2. tobecome less active or strong � thestorm subsided the storm grew quietsubsidencesubsidence /�s�bsd(ə)ns/ noun theact of sinking to a lower level �

Descending air occurs because of sub-sidence in the high pressure belts of thesub-tropics and poles.subsonicsubsonic /s�b |�sɒnk/ adjective fly-ing at speeds slower than the speed ofsound, or not designed to fly above thespeed of soundsubstancesubstance /�s�bstəns/ noun a mate-rial of a particular sort � Specific heat isthe amount of heat required to raise thetemperature of a substance by 1°C (Cel-sius) compared to the amount of heatrequired to raise the temperature ofwater by 1°C.substantialsubstantial /səb |�st�nʃəl/ adjectiveconsiderable, important � substantialdamage a lot of damage � substantialincrease a big increasesubtendsubtend /səb |�tend/ verb to be oppo-site to and delimit � The angle sub-tended by an arc equal to one 360thpart of the circumference of a circle iscalled 1° (degree).subtractsubtract /səb |�tr�kt/ verb to deductor to take away � 6 subtracted from 10equals 4 (10 – 6 = 4).subtractionsubtraction /səb |�tr�kʃən/ noun theoperation of taking away or deducting �The major arithmetic operations areaddition, subtraction, multiplicationand division.subtropicalsubtropical /s�b |�trɒpk(ə)l/ adjec-tive referring to the areas between thetropics and the temperate zone � In win-ter, the subtropical high retreats andgives way to cyclonic pressure patterns.sub-zerosub-zero /�s�b �zərəυ/ adjectivebelow zero degrees � In sub-zero condi-tions sublimation will occur when air iscooled below the frost point, producinga deposit of ice crystals.successsuccess /sək|�ses/ noun the achieve-ment of something wanted � The key to


223 sun

success in navigation is pre-flight plan-ning.successfulsuccessful /sək |�sesf(ə)l/ adjectivesatisfactory, as wanted � His secondattempt at landing was successful.successionsuccession /sək|�seʃ(ə)n/ noun theprocess of following in a particularorder � A succession of minor incidentscreated a more serious situation.successivesuccessive /sək |�sesv/ adjectivefollowing one after the other withoutinterruption � All aircraft remainedgrounded for three successive daysbecause of fog. � A day is the periodbetween successive transits of a merid-ian by the sun.suchsuch /s�tʃ/ adjective 1. of this kind �

An example of such a chart is shown onpage 3. 2. of a large enough extent oramount � The height of the cabin floorto the ground on large jet transports issuch that serious injuries can occur byexiting through the doors when steps orramps are not available.suctionsuction /�s�kʃən/ noun a force thatcauses a fluid or solid to be drawn intoa space because of the differencebetween the external and internal pres-sures � In a fuel injection system, fuel isinduced into the inlet port or combus-tion chamber by a pump rather than thesuction caused by the venturi of a car-burettor.suddensudden /�s�d(ə)n/ adjective immedi-ate and without warning � a suddenchange or sudden drop in temperaturesuffersuffer /�s�fə/, suffer from verb to beaffected by, to experience � Pistonengines suffer from icing in moist airwhen the ambient air temperature iswell above 0°C (Celsius).sufficientsufficient /sə |�fʃ(ə)nt/ adjectiveenough � During pre-flight checks, thepilot must ensure that there is sufficientfuel for the flight.suffixsuffix /�s�fks/ noun an addition to theend of a word creating a new word �

Apart from cirrus and stratus, which arecomplete names, all layer cloud namesconsist of a prefix according to height ofbase, and a suffix according to shape.(NOTE: In the word cloudless, -less isthe suffix meaning without.)

suggest

suggest /sə |�d"est/ verb 1. to indicatea possibility � A strong cloud echo onradar suggests that hailstones arepresent. 2. to mean, to imply � Heapclouds, as the name suggests, often havegreat vertical extent.suit

suit /su�t/ verb to meet the require-ments of � On some engines, the igni-tion can be varied as the engine is run-ning and is moved to suit the enginespeed and load.suitable

suitable /�su�təb(ə)l/ adjective appro-priate or right for a particular purpose �Taking into account the limits imposedby aircraft performance, a suitableroute must be chosen.sulfur

sulfur /�s�lfə/ noun US same as sul-phursulphur

sulphur /�s�lfə/ noun a yellow non-metallic chemical element � Turbinefuels tend to corrode the components ofthe fuel and combustion systems mainlyas a result of the sulphur and water con-tent of the fuel. (NOTE: The atomicnumber of sulphur is 16.)sum

sum /s�m/ noun the result of two ormore numbers added together � Whenthe component velocities act in thesame direction, the resultant velocity isequal to the sum of their speeds in thatdirection.summarise

summarise /�s�məraz/, summa-rize verb to present something in ashortened, concise form � The effects ofice deposits on aircraft can be summa-rised as follows ….summary

summary /�s�məri/ noun a briefaccount of something more detailed �

At the end of each chapter there is asummary.sump

sump /s�mp/ noun the oil reservoir ofa piston engine situated at its base � Theoil level in the sump or tank is normallychecked after the engine has beenstopped for a particular length of time.sun

sun /s�n/ noun a very bright stararound which the Earth travels andwhich gives light and heat � The sunwas just rising when we landed. � Thesun and the planets governed by the sunform the solar system. � solar


sunrise 224sunrisesunrise /�s�nraz/ noun the timewhen the upper edge of the sun appearson the visible horizon. Abbreviation SRsunsetsunset /�s�nset/ noun the time whenthe upper edge of the sun just disap-pears over the horizon. AbbreviationSSsuper-super- /su�pə/ prefix more than nor-malsuperchargesupercharge /�su�pətʃɑ�d"/ verb toincrease the power of an engine byusing a supercharger � A superchargedengine delivers greater power than anon-supercharged engine of the samesize.superchargersupercharger /�su�pətʃɑ�d"ə/ nouna blower or compressor, usually drivenby the engine, for supplying air underhigh pressure to the cylinders of aninternal combustion engine � The func-tion of the supercharger is to increasethe power output and maintain sea-level conditions at altitude.super-cooledsuper-cooled /�su�pə �ku�ld/,supercooled /�su�pəku�ld/ adjectivecooled below freezing point withoutsolidification � supercooled fog � Nim-bostratus cloud is composed of liquidwater droplets some of which are super-cooled.superimposesuperimpose /�su�pərm |�pəυz/verb to lay or to place something overthe top of something else � The compu-ter utilises a technique in which eachsuccessive atmospheric layer is ana-lysed and superimposed on the previousones.superjetsuperjet /�su�pəd"et/ noun a largesupersonic jet aircraftsupersonicsupersonic /�su�pə |�sɒnk/ adjectivefaster than the speed of sound � For sus-tained supersonic flight, tank insulationis necessary to reduce the effect ofkinetic heating.supervisorsupervisor /�su�pəvazə/ noun aperson in charge � senior cabin supervi-sorsupplementsupplement noun /�s�plmənt/ anangle or arc that, when added to a givenangle or arc, makes 180° or a semicircle� verb /�s�plment/ to add to in order tomake more complete � The main powerplant fire detection system should con-

tain an audible warning device to sup-plement the visual indication.supplemental type certificate

supplemental type certificate/�s�plment(ə)l �tap s%�|�tfkət/noun a certificate issued by an airwor-thiness authority to indicate that a mod-ification to an aircraft or engine designhas been approved. Abbreviation STCsupplementarysupplementary /�s�pl |�ment(ə)ri/adjective extra or additional � supple-mentary informationsupplementary anglesupplementary angle/�s�plment(ə)ri ��ŋ$(ə)l/ noun anangle that, when added to a given angle,makes 180°supply

supply /sə|�pla/ noun the amount ofsomething available for use � An enginerequires an adequate supply of oil. �

verb to make available for use, to pro-vide � A battery is designed to supplylimited amounts of electrical power.(NOTE: supplies – supplying – sup-plied)supportsupport /sə |�pɔ�t/ noun 1. a device tohold something in position � Direct-reading indicators consist of a floatcontained within a metal support tube.2. practical assistance � verb to bear theweight of � The wings support the air-craft in flight.support facilitiessupport facilities /sə |�pɔ�t fə |

�sltiz/ plural noun equipment andbuildings used by ground staff whenworking on aircraft at an airportsupport servicessupport services /sə |�pɔ�t�s%�vsz/ plural noun services providedto an aircraft while it is at an airportsuppress

suppress /sə |�pres/ verb 1. to preventthe development or spreading of some-thing � the fire crew suppressed thefire the fire crew brought the fire undercontrol 2. to prevent electrical interfer-ence from affecting a radio signal � R/Tnoise interference can be suppressed.suppressed antennasuppressed antenna /sə |�prest �n |

�tenə/ noun an antenna which ismounted under the airframe skin �

Static interference can be reduced byinstalling suppressed antennas.suppression

suppression /sə |�preʃ(ə)n/ noun 1.the prevention of the development orspreading of something � a fire suppres-


225 susceptible

sion system 2. the prevention of electri-cal interference of a radio signalsuppressorsuppressor /sə|�presə/ noun a deviceused in an electrical or electronic sys-tem to reduce unwanted currents, e.g. aresistor or grid � A suppressor improvesthe quality of the signal.surfacesurface /�s%�fs/ noun 1. an outer cov-ering of something, or the top part ofsomething � the surface of the wing 2.the Earth’s surface or groundsurface air temperaturesurface air temperature /�s%�fs�eə �temprtʃə/ noun the temperaturerecorded in the shade at a height justabove ground levelsurface frontsurface front /�s%�fs fr�nt/ noun aweather front at the surface of the earth� The cirrus cloud can be 900 milesahead of the surface front with a rainbelt as wide as 200 miles.surface heatingsurface heating /�s%�fs �hi�tŋ/noun the heating of the ground by thesunsurface movement radarsurface movement radar noun atype of radar used at airports to monitoraircraft traffic on the ground. Abbrevia-tion SMRsurface synoptic chartsurface synoptic chart /�s%�fs s |

�nɒptk �tʃɑ�t/ noun a chart of a geo-graphical area with symbols, fronts andisobars giving a representation of theweather over the area at a particulartimesurface tensionsurface tension /�s%�fs �tenʃ(ə)n/noun the tension of the surface film of aliquidsurface windsurface wind /�s%�fs wnd/ noun awind which blows across the land sur-facesurgesurge /s%�d"/ noun a sudden increasein something such as electrical power �engine surge instability in the poweroutput of an engine � verb to move withforce like a wave � If combustion pres-sure increases above compressor outletpressure, the airflow will reverse indirection and surge forward through thecompressor.surplussurplus /�s%�pləs/ adjective excess,more than is needed � Fuel penaltiescan be incurred if fuel surplus torequirements is carried.

surroundsurround /sə |�raυnd/ noun somethingwhich encloses or borders � The designof windows, hatches or door surroundsis very critical. � verb to encircle or toenclose � The Earth is surrounded bythe atmosphere.surveillancesurveillance /sə|�veləns/ noun theact of watching or monitoringsurveillance radarsurveillance radar /sə|�veləns�redɑ�/ noun primary radar scanning,often through 360°surveysurvey noun /�s%�ve/ a detailedexamination � An aerodrome meteoro-logical office maintains a continuoussurvey of meteorological conditionsover the aerodromes for which it is des-ignated to prepare forecasts. � verb /sə|

�ve/ to determine the boundaries, area,or elevations of land by means of meas-uring angles and distances � Take carewhen using wooded areas to fix positionbecause the cutting down of trees mayhave led to a change in shape since themap was made.survivalsurvival /sə |�vav(ə)l/ noun the fact ofremaining alive after an accident � Thesurvival of passengers in the seadepends on rapid location and rescue.

‘…survival training is a vital element ofall aircrew knowledge. Just becausemodern aircraft are more reliable thantheir predecessors, the need for suchtraining does not diminish’ [CivilAviation Training]

survival beaconsurvival beacon /sə |�vav(ə)l�bi�kən/ noun a beacon which transmitsa signal which enables search aircraft tolocate survivors in the water � VHFand/or UHF survival beacons are car-ried on all jet transports.survivorsurvivor /sə |�vavə/ noun a personwho continues to live after an accident� Whilst awaiting rescue on land or atsea, survivors should avoid exposureand conserve energy. � The aircraftcrashed into the sea and there were nosurvivors.susceptiblesusceptible /sə |�septb(ə)l/ adjectiveprone to, likely to be affected by � Arough surface is more susceptible tofatigue cracking than a smooth one, andfor this reason highly stressed membersare often polished.


suspect 226suspectsuspect adjective /�s�spekt/ refer-ring to something believed to be caus-ing problems � The magnetic flawdetection technique is to induce a mag-netic field in the suspect part and thento brush over it an ink containing amagnetic powder. � verb /sə|�spekt/ tobelieve to be the case � If fuel contami-nation by water is suspected, a sampleof fuel should be drained from the tankfor inspection.suspendsuspend /sə |�spend/ verb 1. to hangfreely from a point � When it is freelysuspended, a magnet will turn until onepole is towards the Earth’s magneticnorth pole. 2. to float freely in the air orin a liquid � The weather associatedwith visibility reductions by particlessuspended in the atmosphere is classi-fied as fog, mist, haze or smoke.suspensionsuspension /sə |�spenʃən/ noun 1.the act of state of hanging freely from apoint 2. the dispersion of particles in aliquid or gas � If a sample of fuel takenfrom a tank is hazy or cloudy in appear-ance, this indicates the presence ofwater in suspension.sustainsustain /sə|�sten/ verb 1. to continue,to maintain � For sustained supersonicflight, some measure of tank insulationis necessary to reduce the effect ofkinetic heating. 2. to receive, experi-ence or suffer � The aircraft sustainedmajor damage in the crash. � The pilotsustained minor injuries.sweepsweep /swi�p/ verb to move acrossquickly and with force � Cold arctic airsweeps over North America in winter.sweepbacksweepback /�swi�pb�k/ noun an air-craft wing that slopes backwardstowards the tail, forming an acute anglewith the body of the aircraftswellswell /swel/ noun a long wave onwater that moves continuously withoutbreaking � When ditching an aircraftthe selection of a landing directionwhich will result in the minimum rela-tive speed between the aircraft and seaswell will reduce impact forces andminimise structural damage.sweptbacksweptback /�sweptb�k/ adjectivereferring to a wing that slopes back-wards towards the tail of the aircraft

sweptwingsweptwing /�sweptwŋ/ adjectivereferring to an aircraft that has swept-back wingsswingswing /swŋ/ verb 1. to move fromside to side with some force � There isoften a tendency for a propeller drivenaircraft to swing or yaw on take-off. 2. �to swing a compass to calibrate com-pass deviation by recording its value ona compass base while rotating the air-craft through 360° 3. � to swing a pro-peller to turn a propeller by hand tostart the engineswirlswirl /sw%�l/ noun a movement with atwisting motion � Swirls of smoke cameout of the engine.swirl chamberswirl chamber /sw%�l �tʃembə/noun a small chamber in the cylinderhead to promote swirl � The usualmethod of atomising the fuel is to pass itthrough a swirl chamber, so convertingits pressure energy to kinetic energy.switchswitch /swtʃ/ noun a device to openor break an electric current � There is anon/off switch on the front panel. � cen-trifugal switch a switch operated bycentrifugal force � verb to connect ordisconnect two lines by activating aswitch � to switch on to start to providepower to a system by using a switch �

Switch on the light. � to switch off todisconnect the power supply to a deviceor system � Switch off the navigationlights.symbolsymbol /�smbəl/ noun a printed orwritten sign used to represent some-thing � The work done by an electricalcircuit or the power consumed is meas-ured in watts and is given the symbol P.symbolicsymbolic /sm |�bɒlk/ adjective refer-ring to symbols � A symbolic code isused for synoptic charts.symmetricsymmetric /s |�metrk/, symmetri-cal /s|�metrk(ə)l/ adjective referringto something which has an exact like-ness of form on opposite sides of a cen-tral dividing line � The area covered bythe forecast is divided into a series ofgrid or reference points at approxi-mately 300 km (kilometres) symmetricalspacing.symptomsymptom /�smptəm/ noun a sign orindication of something, possibly a


227 system

problem � Buffet caused by turbulentairflow acting on the tailplane is one ofthe first symptoms of the approachingstall.synchronisationsynchronisation /�sŋkrəna |

�zeʃ(ə)n/, synchronization nounoccurrence at the same time or rate �

Prior to engagement, when the aircraftis being flown manually, the autopilotsystem will be following the aircraftflight attitude, thus ensuring that syn-chronisation is achieved.synchronisesynchronise /�sŋkrənaz/, syn-chronize verb to cause to occur or oper-ate at the same time or rate � The air-craft must be trimmed for the desiredflight attitude before engaging the auto-pilot, which must be synchronised tomaintain that attitude when it isengaged.synchronoussynchronous /�sŋkrənəs/ adjectivereferring to something operating at the

same time or rate � Synchronous motorswill run at constant speed and are smalland light in weight.synoptic

synoptic /s|�nɒptk/ adjective refer-ring to something which gives a briefoutline or general view of somethingmore complex � With the addition offronts and isobars, the synoptic chartprovides a representation of theweather over a large area, at a particu-lar time.synthetic

synthetic /sn|�θetk/ adjective notnatural, artificial � Mineral-based fluidsare normally coloured red, and must beused with synthetic rubber seals andhoses.system

system /�sstəm/ noun a group ofinterdependent parts forming and oper-ating as a whole � a braking system � anelectrical system


Ttab

tab /t�b/ noun the hinged rear part offlight control surface used for trimming� Trim tabs remove the pilot’s controlloads by aerodynamically holding thecontrol surface in the required position.table

table /�teb(ə)l/ noun a set of facts orfigures displayed in columns and rows �Charts are issued at UK meteorologicaloffices and show, for selected locations,a table of winds and temperatures atselected flight levels.tabular

tabular /�t�bjυlə/ adjective � in tab-ular form arranged in a table � Themost widely acceptable presentation offuel data is in tabular form but graphi-cal presentations may also be used.Tacan

Tacan /�t�kən/ noun an aircraft navi-gation system that uses UHF signalsfrom a transmitting station for distanceand bearing. Full form Tactical areanavigation aidtachometer

tachometer /t� |�kɒmtə/ noun aninstrument for the measurement of rev-olutions per minute of a rotating shaft �The pilot checks the tachometer andnotes the resulting drop in r.p.m. foreach magneto.TAF

TAF abbreviation 1. terminal aero-drome forecast 2. aerodrome forecast(ICAO)tail

tail /tel/ noun the rear part of the air-craft � The tail section is the aft part ofthe fuselage to which is fitted the tailunit, comprising the tailplane, eleva-tors, fins and rudders.tail assembly

tail assembly /�tel ə|�sembli/ nounthe aft part of the fuselage with the finand rudder, tailplane and elevatorsattached

tail-draggertail-dragger /�tel �dr�$ə/ nounsame as tailwheel aircraft (informal )tailplanetailplane /�telplen/ noun a horizon-tal stabiliser, a horizontal aerofoil at therear of the aircraft � On most high per-formance aircraft the incidence of thehorizontal stabiliser (or tailplane) canbe varied in flight.tail rotortail rotor /�tel �rəυtə/ noun a smallrotor on the tail of a helicopter that pre-vents the helicopter from spinning inthe direction opposite to the rotation ofthe main rotortailskidtailskid /�telskd/ noun a support orrunner on the underside of the tail of anaircrafttailspintailspin /�telspn/ noun a rapid anduncontrolled spiral descent of an air-crafttail unittail unit /�tel �ju�nt/ noun the rearpart of the aircraft, usually consisting ofthe fin and tailplanetailwheeltailwheel /�telwi�l/ noun a smallwheel under the tail of an aircraft. Com-pare nosewheeltailwheel aircrafttailwheel aircraft /�telwi�l�eəkrɑ�ft/ noun aircraft with a smallwheel at the tail instead of a nosewheel.Also called tail-draggertailwheel conversion coursetailwheel conversion course/�telwi�l kən |�v%�ʃ(ə)n �kɔ�s/ noun acourse which familiarises qualifiedpilots with the differences in handlingcharacteristics between nosewheel andtailwheel aircrafttailwindtailwind /�telwnd/ noun a windwhich is blowing in the same directionas the direction of movement or flight �Because of the tailwind, the flight tookonly six hours. Compare headwind


229 technologytake offtake off /�tek �ɒf/ verb to leave theground � When flying speed is reachedthe aeroplane takes off.take-offtake-off /�tek ɒf/, takeoff /�tekɒf/noun the procedure when an aircraftleaves the ground � The aircraft has toaccelerate before take-off. � There is atendency for propeller driven aircraft toswing or yaw on take-off. AbbreviationTO, T/Otake-off runtake-off run /�tek ɒf �r�n/ noun thedistance from the start of take-off to thepoint where the wheels leave the ground� Acceleration forces can be felt as theaircraft begins its take-off run.take-off weighttake-off weight /�tek ɒf �wet/noun the weight of an aircraft at take-off, made up of its empty weight, plusthe weight of its passengers, freight andfueltalk downtalk down /�tɔ�lk �daυn/ verb to giveadvice to a pilot by radio on how to landan aircrafttantan abbreviation tangenttangenttangent /�t�nd"ənt/ noun a straightline, curve or surface which meetsanother curve or curved surface at apoint, but which, if extended, does notcut through at that point � The glidepath is at a tangent to the runway.Abbreviation tantangentialtangential /t�n |�d"enʃ(ə)l/ adjectivepositioned at a tangent to somethingelsetanktank /t�ŋk/ noun a large container forstoring fluid � An aluminium alloy fueltank is housed in each wing.tapertaper /�tepə/ verb to reduce in thick-ness towards one end � Fuel flowingfrom the float chamber passes through ajet, in which is positioned a taperedneedle valve.tapered wingtapered wing /�tepəd wŋ/ noun awing which becomes narrower in widthfrom root to tiptargettarget /�tɑ�$t/ noun the indicationshown on a radar screen resulting froma primary radar return or a radar beaconreply � In a secondary radar system, thetarget is active.tarmactarmac /�tɑ�m�k/ noun the runwayand taxiways of an airport � They were

working fast to clear the snow from thetarmac.TASTAS abbreviation true airspeedtasktask /tɑ�sk/ noun a function or duty �

Present day transport aircraft arerequired to fly accurately, in allweather, for long distances or long peri-ods of time and, in order to carry outthis task efficiently, an autopilot is used.taxitaxi /�t�ksi/ verb to move an aircraftalong the ground under its own powerbefore take-off or after landing � Lightaircraft can be steered while taxiing viaa direct link from rudder pedals to thenosewheel. (NOTE: taxies – taxiing –taxied; the US English is taxying.)taxiingtaxiing /�t�ksiŋ/ noun the movementof an aircraft along the ground under itsown power before take-off or after land-ing � the landing and taxiing of an air-craft � The taxiing of tail-wheel aircraftis more difficult than nosewheel air-craft. (NOTE: The US spelling is alsotaxying.)taxiwaytaxiway /�t�ksiwe/ noun a tarmacsurface connecting the ramp or apronwith the runway � an airfield, i.e. anarea given over to runways, taxiwaysand apronsTCATCA abbreviation terminal control areaTCASTCAS abbreviation traffic alert andcollision avoidance systemTCDSTCDS abbreviation type certificatedata sheettechnicaltechnical /�teknk(ə)l/ adjective 1.referring to mechanical subjects orapplied sciences � a technical educa-tion 2. referring to the mechanical, elec-trical, hydraulic or pneumatic systemsof an aircraft � A technical problem withthe aircraft prevented it from taking offon time.techniquetechnique /tek |�ni�k/ noun a specialmethod for doing something � Thepreparation of charts is done by compu-ter using numerical forecasting tech-niques.technologytechnology /tek|�nɒləd"i/ noun thestudy and use of the mechanical arts orapplied sciences � new technology newelectronic equipment � The use of fly-by-wire in airliners was delayed toallow thorough development and


TEHP 230

encourage universal acceptance of thenew technology.TEHP

TEHP abbreviation total equivalenthorsepowertelemetry

telemetry /tə |�lemtri/ noun the workof recording and transmitting data aboutan object situated at a distance from theobserverTEMP

TEMP /temp/ abbreviation tempera-turetemperate

temperate /�temp(ə)rət/ adjectivemild, not extreme � Cold air in temper-ate latitudes is usually unstable.temperature

temperature /�temprtʃə/ noun ameasurement, in degrees, of the inten-sity of heat of a body � Ground temper-ature is the temperature recorded by athermometer placed at ground level. �

The altitude and temperature of the tro-popause are of concern to aircrew.temperature error

temperature error /�temprtʃə�erə/ noun the variation in pressure alti-tude caused by a deviation of tempera-ture from ISAtempo

tempo /�tempəυ/ noun the speed of anactivity � The flow of passengers toexits and tempo of evacuation will beinfluenced by the number of exits avail-able.TEMPO

TEMPO /�tempəυ/ abbreviation tem-porary (ICAO)temporary

temporary /�temp(ə)rəri/ adjectivelasting for a short time, not permanent �The indicator ‘tempo’, followed by a 4-figure time group indicates a period oftemporary fluctuations to the forecastmeteorological conditions which mayoccur at any time during the periodgiven. Opposite permanenttend

tend /tend/ verb to be apt or inclinedto do something more often than not �

Depressions tend to move around largeanticyclones following the circulationof wind. � the weather tends to be wetin the UK in the winter the weather isoften, but not always, wettendency

tendency /�tendənsi/ noun an incli-nation, situation or condition whichoccurs more often than not � There is atendency for propeller-driven aircraftto swing or yaw on take-off. � he has a

tendency to be late he is often late � hehas a tendency to forget things he isforgetfultensile

tensile /�tensal/ adjective referring tostretching or pulling out � Reinforcedplastic may have to support a tensileload, a compressive load or a bendingload.tensile load

tensile load /�tensal ləυd/ noun theload caused by forces acting in oppositedirections away from each othertensile strength

tensile strength /�tensal streŋθ/noun the strength of a structure to resistforces pulling it apart from oppositedirectionstensile stress

tensile stress /�tensal stres/ nounthe forces that try to pull a structureapart from opposite directionstension

tension /�tenʃən/ noun a strainedcondition resulting from forces actingin opposition to each other � A rodwhich is bent is shortened or in com-pression on the inside of the bend and isstretched or in tension on the outside ofthe bend.term

term /t%�m/ noun 1. a word or expres-sion � The term ‘payload’ includes pas-sengers, baggage and freight. 2. a lim-ited period of time � a 5 year term aperiod of 5 years � in the long termwhen considering a long period of time� short term forecast a weather fore-cast for the next few hours onlyterminal

terminal /�t%�mn(ə)l/ adjective refer-ring to a limit or to a final point � noun1. the departure and/or arrival buildingat an airport � The flight leaves from ter-minal three at Heathrow airport. 2. anelectrical connection point � The nega-tive terminal of the battery is marked -.terminal aerodrome forecast

terminal aerodrome forecast/�t%�mnəl �eərədrəυm �fɔ�kɑ�st/noun the weather forecast for the areaaround an aerodrome � In terminal aer-odrome forecasts, the height of thecloud base forecast is above airfieldlevel unless otherwise stated. Abbrevia-tion TAF

COMMENT: TAFs are scheduled fourtimes daily for 24-hour periodsbeginning at 0000Z, 0600Z, 1200Z,and 1800Z.


231 thermal activityterminal airfieldterminal airfield /�t%�mn(ə)l�eəfi�ld/ noun the airfield at which aflight finishesterminal area forecastterminal area forecast/�t%�mn(ə)l �eəriə �fɔ�kɑ�st/ noun theweather forecast for the area around anairport. Abbreviation TAFterminal control areaterminal control area /�t%�mn(ə)lkən |�trəυl �eəriə/ noun an air trafficcontrol area established at the meetingplace of a number of routes near one ormore major airports � In some areaswhere there is a local concentration oftraffic, terminal control areas are setup. Abbreviation TCA, TMAterminateterminate /�t%�mnet/ verb to end, orto bring to a close � The flight termi-nates in New York. � the transmissionterminated abruptly the transmissionstopped suddenly and unexpectedlyterminologyterminology /�t%�m|�nɒləd"i/ noun aset of words or expressions used for aparticular subject � It is necessary tolearn some of the terminology associ-ated with aircraft navigation.terrainterrain /tə |�ren/ noun land, especiallyin relation to its physical geography �

Special attention should be paid to windflow when flights are made over hills ormountainous terrain.terrestrialterrestrial /tə|�restriəl/ adjectivereferring to the earth � Clear skies allowterrestrial radiation to escape.territoryterritory /�tert(ə)ri/ noun the extentof the surface of the Earth governed bya particular country, ruler, state, etc. �

All places in the same territory, or partof the same territory, maintain a stand-ard of time as laid down by the govern-ment responsible for that territory.tertiarytertiary /�t%�ʃəri/ adjective referringto something which is third in order ofrank, behind primary and secondary �

Tertiary radar systems are synonymouswith long-range navigation aids. � Ter-tiary structures, for example fairings,wheel doors and minor componentbrackets, are essential parts of the air-frame.tertiary radartertiary radar /�t%�ʃəri �redɑ�/ nounlong-range navigation aidstesttest /test/ noun 1. a series of opera-tions to find out if something is working

well � The manual test for the enginefire warning system will give a steadyred light on all the fire control handles.2. an examination to assess the knowl-edge of a person � There is a navigationtest for students at 0800 hours. � verb 1.to operate something in order to find outwhether it functions correctly � Oxygenunder pressure is used to test the oxygenmasks and equipment for fit and leak-age. 2. to examine somebody in order toassess his or her knowledge � The stu-dents are tested in five subjects.test pilottest pilot /�test �palət/ noun a pilotwho flies new aircraft in order to checktheir performanceTGTTGT abbreviation turbine gas tempera-turetheorytheory /�θəri/ noun a system of ideasor principles explaining something �

The theory of navigation must be stud-ied before any practical plotting exer-cises are done.theory of flighttheory of flight /�θəri əv �flat/noun the ideas and principles whichcontribute to our understanding of howthings flythereafterthereafter /ðeər|�ɑ�ftə/ adverb afterthat, beyond that � Meteorological visi-bility is given in metres up to 5,000metres and thereafter in km (kilome-tres).therebythereby /ðeə |�ba/ adverb by thatmeans or in that way � The evacuationwas carried out at a slower rate,thereby minimising the risk of injury topassengers.thereforetherefore /�ðeəfɔ�/ adverb as a result,consequently � At small throttle open-ings, the depression at the choke is verysmall and therefore no fuel flows fromthe main jet.thermalthermal /�θ%�m(ə)l/ adjective refer-ring to heat � Intense surface heatingcauses thermal currents to develop andcreate convection. � noun a rising cur-rent of relatively warm air in the loweratmosphere � Glider pilots circle inthermals in order to gain height.thermal activitythermal activity /�θ%�m(ə)l �k|

�tvti/ noun a period of time whenthere is a lot of vertical movement of aircaused by heating � Cumulus clouds


thermal barrier 232

may develop because of thermal activityresulting from the warming of the sur-face.thermal barrierthermal barrier /�θ%�m(ə)l �b�riə/noun the heat caused by air friction onan aircraft flying at high speedthermo-thermo- /θ%�məυ/ prefix heatthermocouplethermocouple /�θ%�məυk�p(ə)l/noun a device for measuring tempera-ture � Variation in temperature of thecooling air will give some indication ofengine trouble through a thermocouplesystem to a temperature gauge.thermodynamicthermodynamic /�θ%�məυda|

�n�mk/ adjective referring to the con-version of one form of energy intoanother and how this affects tempera-ture, pressure, volume, mechanicalaction and workthermometerthermometer /θə |�mɒmtə/ noun aninstrument for measuring temperature �Ground temperature is the temperaturerecorded by a thermometer placed atground level.thermoplasticthermoplastic /�θ%�məυ|�pl�stk/noun a type of plastic which can be sof-tened by heating then shaped, then sof-tened again by heatingthermosetting plasticthermosetting plastic/�θ%�məυsetŋ �pl�stk/ noun a type ofplastic which is heated while beingshaped but which cannot be softened byreheating � If a piece of thermosettingplastic is hit hard enough, it breaks intopieces with straight sharp edges.thickthick /θk/ adjective 1. of great or par-ticular extent between two surfaces � a1cm thick steel bar � This sheet of alu-minium is not very thick. 2. with a largediameter � thick wire 3. dense � thickfog � thick cloud 4. of a consistencywhich does not flow easily � thick oilOpposite thinthicknessthickness /�θknəs/ noun 1. theextent between two surfaces � In mono-coque construction, there is no internalstiffening because the thickness of theskin gives strength and stability. 2. theextent of the diameter of a wire 3. thestate or condition of being thickthinthin /θn/ adjective 1. of small extentbetween two surfaces � a thin layer ofpaint 2. with a small diameter � thin

wire 3. not dense � thin mist � Altostra-tus cloud is thin enough for the sun to bedimly visible. 4. of a consistency whichflows easily � thin oil Opposite thickthinnessthinness /�θnnəs/ noun 1. a smallextent between two surfaces � The thin-ness of the material makes it unsuitable.2. a small extent of the diameter of awire 3. the state or condition of beingthinthoroughthorough /�θ�rə/ adjective complete� All cabin crew must have a thoroughknowledge of fire fighting equipmentand procedures. � a thorough inspec-tion a very detailed, comprehensiveinspectionTHPTHP abbreviation thrust horsepowerthree-letter groupthree-letter group /�θri� �letə�$ru�p/ noun three letters of the alpha-bet found togetherthree-point landingthree-point landing /�θri� �pɔnt�l�ndŋ/ noun an aircraft landing inwhich the two main wheels of the land-ing gear and the nosewheel or tailwheeltouch the ground at the same timethresholdthreshold /�θreʃhəυld/ noun thebeginning of the part of the runway,usable for landing � Runway visualrange is obtained by an observer stand-ing at the side of the runway in thevicinity of the threshold counting thenumber of markers or lights visiblealong the side of the runway.

COMMENT: The threshold is markedwith a single white line on visualrunways or by eight parallel white linesarranged longitudinally in two groupsof four each side of the runwaycentreline for runways with instrumentapproach/landing facilities.

throttlethrottle /�θrɒt(ə)l/ noun 1. a throttlelever 2. a throttle valve � verb � tothrottle back to reduce engine power �Throttle back to increase the rate ofdescent.

COMMENT: The verbs ‘open’ or‘advance’ (= to increase engine power)and ‘close’ or ‘throttle back’ (= todecrease engine power) are frequentlyused by instructors to explain therequired movement of the throttle leverin the cockpit.

throttle leverthrottle lever /�θrɒt(ə)l �li�və/ nouna device operating the throttle valve �


233 tire

When starting an engine, it is inadvisa-ble to pump the throttle lever because ofthe risk of fire.throttle quadrantthrottle quadrant /�θrɒt(ə)l�kwɒdrənt/ noun an arc-shaped devicein which the throttle levers movethrottle settingthrottle setting /�θrɒt(ə)l �setŋ/noun the particular position of the throt-tle which gives a required revolutionsper minute or powerthrottle valvethrottle valve /�θrɒt(ə)l v�lv/ nouna device controlling the flow of fuel inan enginethroughoutthroughout /θru |�aυt/ adverb fromthe beginning to the end of a time orplace � Emergency lighting is providedthroughout the cabin. � Heavy snow fellthroughout the night. � throughout thelife of the aircraft during the entire lifeof the aircraft � throughout the worldall over the world � throughout theyear from January 1st to December31stthrustthrust /θr�st/ noun a force producedby a propeller, jet or rocket � A propel-ler is a means of converting enginepower into a propulsive force known asthrust. � In order for the aircraft toincrease speed, thrust must overcomedrag. � reversal, reverser � verb topush suddenly with force � A nozzle isan opening at the rear of a jet enginethrough which exhaust gases are thrust.(NOTE: thrusting – thrust)thrust horsepowerthrust horsepower /�θr�st�hɔ�spaυə/ noun the amount of horse-power of an engine that is transformedinto thrust. Abbreviation THPthrust reversalthrust reversal /�θr�st r|�v%�səl/noun setting of throttle levers to providethrust in the opposite direction to decel-erate the aircraft after landingthunderthunder /�θ�ndə/ noun the noise cre-ated by the violent expansion and con-traction of air momentarily heated by alightning discharge � Thunder immedi-ately following the flash of lightningusually indicates that the storm is over-head.thunderstormthunderstorm /�θ�ndəstɔ�m/ nouna violent weather condition in whichwind speeds increase, rain or hail fallsand there is lightning activity � Thun-

derstorms occur in well-developedcumulonimbus clouds. � The process offormation, development and decay of athunderstorm.thunderstorm activity

thunderstorm activity/�θ�ndəstɔ�m �k |�tvti/ noun theoccurrence of weather conditions asso-ciated with thunderstorms, such as rain,thunder, wind or lightningthusthus /ð�s/ adverb 1. in this way � Thisdevice fits with the other thus. 2. there-fore, as a result � The glide slope andlocaliser beam signals control the air-craft about the pitch and roll axes, thusmaintaining alignment with the runway.� Anti-skid braking systems aredesigned to prevent the brakes lockingthe wheels during landing, thus reduc-ing the possibility of wheel skid.tie

tie /ta/ noun a basic structural memberwhich is designed to withstand mainlytensile loads � Diagonal ties can beused to relieve tension and increase theeffectiveness of the top boom.tighttight /tat/ adjective closely or firmlyfitting or put together � a tight fit a sit-uation when there is just about enoughspace to fit � adverb closely or firmly,with no air leaks � The door must beshut tight.tilt

tilt /tlt/ noun a sloping position � Landcreates a drag effect on an electro-mag-netic wave-front, reducing the velocityof the wave thereby causing a tilt. � verbto be at an angle to the vertical or hori-zontal, to slope � The Earth tilts on itsaxis.timetable

timetable /�tamteb(ə)l/ noun aprinted list which shows the times ofdeparture from and arrival to variousdestinations � All the scheduled flightsare listed in the airline timetable.timetabledtimetabled /�tamteb(ə)ld/ adjec-tive listed in a timetable � A scheduledlanding is an arrival at a timetableddestination.time zonetime zone /�tam zəυn/ noun one ofthe 24 parts of the Earth in which thesame standard time is usedtip

tip /tp/ noun the end of a small ortapering thingtire

tire /�taə/ noun US same as tyre


titanium 234titaniumtitanium /ta|�teniəm/ noun a lightmetal used to make strong alloys � Thefatigue resistance of titanium is greaterthan that of aluminium or steel.TKOFTKOF abbreviation take off (ICAO)TMATMA abbreviation terminal controlareaT/OT/O, TO abbreviation take offtoggletoggle /�tɒ$(ə)l/ noun a short piece ofwood or other material, attached with astring to e.g. a life jacket � Pull the tog-gles downwards to inflate the life jacket.toilettoilet /�tɔlət/ noun 1. a bowl with aseat on which you sit to get rid of wastefrom your body 2. a room or cubiclewith a toilet bowl in it � There are twotoilets at the rear of the plane and oneat the front.tolerancetolerance /�tɒlərəns/ noun an allow-able variation in something which canbe measured � a tolerance of 2° � a tol-erance of 1mm (millimetre)tonetone /təυn/ noun a sound of one pitch� The ground transmits a code in twoshort bursts each of which is modulatedwith two tones.tool kittool kit /�tu�l kt/ noun a set of toolsconsisting of spanners, screwdrivers,pliers, etc.toptop /tɒp/ noun the highest point or part� If cumulonimbus clouds cannot beavoided then flight through the top isless hazardous than through the centreor bottom of the cloud.top-dead-centretop-dead-centre /�tɒp ded �sentə/noun the position of the piston at theextreme top of its stroke in a pistonengine � Ignition should occur justbefore top-dead-centre.topictopic /�tɒpk/ noun the subject ofsomething heard, said, written or read �The first section in the book deals withthe topic of airmanship.topographicaltopographical /�tɒpə |�$r�fk(ə)l/adjective referring to topography � Anadvantage of using airfield QNH is thataltimeter readings can be compareddirectly with heights represented ontopographical maps.topographytopography /tə|�pɒ$rəfi/ noun 1. arepresentation of detailed natural andman-made features of the Earth’s sur-

face as represented on a map � Thechart shows the topography of the area.2. relative elevations of the Earth’s sur-face, or features of a geographical area� The general circulation is compli-cated because the Earth tilts and its sur-face is neither level, because of topog-raphy, nor uniform due to areas of landand sea.tornado

tornado /tɔ�|�nedəυ/ noun a violentstorm of small extent, with rotatingwinds � The winds of a tornado are ofhurricane force.torque

torque /tɔ�k/ noun a moment of forcescausing rotation � Torque forces try tobend the propeller against the directionof rotation. � High current flowsthrough both the field and armaturewindings producing the high torquerequired for engine starting.torquemeter

torquemeter /�tɔ�kmitə/ noun adevice for measuring forces (torque)causing rotation � Engine torque is usedto indicate the power that is developedby a turboprop engine and the indicatoris known as a torquemeter.torsion

torsion /�tɔ�ʃ(ə)n/ noun twisting,especially of one end of a body whilethe other is fixed � Rivets are subjectedto torsion and may break.torsion load

torsion load /�tɔ�ʃ(ə)n ləυd/ nounthe load caused by twisting of a struc-turetotal

total /�təυt(ə)l/ adjective complete,whole � Of the total amount of radia-tion emitted by the sun, the Earthreceives only a very small part. � totalsystem failure complete system failure� total seating capacity the maximumnumber of passengers who can beaccommodated on seatstouch down

touch down /�t�tʃ �daυn/ verb tomake controlled contact with the land-ing surface after a flight � If the atmos-pheric pressure at an airfield is 1,000millibars (mb) and that pressure is seton the sub-scale of an aircraft altimeter,when the aircraft touches down at theairfield, the altimeter will read zero.touchdown

touchdown /�t�tʃdaυn/ noun themoment, after a flight, when the aircraftmakes controlled contact with the land-


235 transform

ing surface � One of the aircraft’s tyresburst on touchdown.touchdown pointtouchdown point /�t�tʃdaυnpɔnt/ noun the place on the runwaywhere the aircraft undercarriage firsttouches the ground on landingtowtow /təυ/ verb to pull an aircraft orvehicle using a bar, rope, etc. attachedto another aircraft or vehicle � Theglider was towed into the air by a Rol-lason Condor.towertower /�taυə/ noun a tall airport or air-field air traffic control building � Waitfor permission from the tower beforecrossing an active runway.‘T’ piece adapter‘T’ piece adapter /�ti� �pi�s ə |

�d�ptə/ noun a device for connectingtwo inputs to one output or vice versatracktrack /tr�k/ noun a projection on theEarth’s surface of the path of an aircraft,which can be expressed in degrees fromnorth � Where an aircraft track andwind direction are the same, there willbe a headwind component acting on theaircraft. � The actual track does notnecessarily follow the planned trackand is given the name track made good.� verb to follow a line of the flight pathof an aircraft, as projected on the Earthsurface � On final approach, track theimaginary extended centre line of therunway.tractortractor /�tr�ktə/ noun 1. an aircraftthat has its propeller in front of itsengine 2. a propeller in front of an air-craft engine, which has the effect ofpulling the aircraft through the airtrade windstrade winds /�tred wndz/ pluralnoun steady winds which blow on theside of the sub-tropical highs nearest tothe equator � Trade winds maintaintheir direction over the oceanic areas,especially the Pacific, more than overland areas.traffictraffic /�tr�fk/ noun the number ofaircraft in operation � Standard instru-ment routes are structured to providethe safest and most efficient flow of traf-fic from entry and exit points to the air-field.traffic patterntraffic pattern /�tr�fk �p�t(ə)n/noun 1. the shape marked out on theground of an aircraft track in the aero-

drome circuit 2. the pattern of routesthat an aircraft must keep to whenapproaching or circling an airporttrailingtrailing /�trelŋ/ adjective referring tosomething which comes after some-thing else � The trailing brush is posi-tioned behind the main brush on therotor arm, thereby giving a retardedspark.trailing edgetrailing edge /�trelŋ �ed"/ noun aftpart of an aerofoil � The trailing edge ofthe wing is the section behind the rearspar and is of light constructionbecause the aerodynamic loads on thisarea are relatively low.traintrain /tren/ verb to teach a person aparticular skill � The student pilot istrained to scan an instrument panel,whilst at the same time listening to theaircraft radio and flying the aircraft. �

noun a series of connected parts orwheels in machinery � The turbopropturbine transmits increased power for-ward through a shaft and a gear train,to drive the propeller.traineetrainee /tre|�ni�/ noun a person who isbeing taught � a trainee pilottransducertransducer /tr�nz |�dju�sə/ noun adevice which converts a non-electricalsignal into an electrical one � The man-ifold is connected into the pressure ratiotransmitter, which consists of a trans-ducer, to sense the pressure ratio, andan associated electrical circuit, provid-ing signals to the servo indicator in thecockpit.transfer

transfer noun /�tr�nsf%�/ the act ofpassing or moving to another place �

External cooling of the engine is neces-sary to prevent the transfer of heat tothe aircraft structure. � verb /tr�ns |�f%�/to pass or to move to another place � Itis sometimes necessary to transfer fuelfrom one tank to another tank. (NOTE:transferring – transferred)transformtransform /tr�ns|�fɔ�m/ verb tochange completely � The purpose of anactuator is to transform fluid flow intomotion, i.e. it converts pressure energyinto mechanical energy. � Frictionresults in some of the power availablefrom a pump being transformed intoheat.


transformer 236transformer

transformer /tr�ns|�fɔ�mə/ noun adevice for changing the voltage or cur-rent amplitude of an alternating currentsignal � Current transformers differfrom voltage transformers in that theprimary circuit consists of a supplyfeeder cable rather than a coil con-nected across a supply.transient

transient /�tr�nziənt/ adjective pass-ing or temporary, lasting only a shorttime � Transient loads can be absorbedby the busbar with a minimum of volt-age fluctuations.transit

transit /�tr�nzt/ noun an act of mov-ing � in transit moving � A green lightindicates the undercarriage is lockeddown, and a red light is displayed whenthe undercarriage is in transit. � transitroute a route taken by one aircraftthrough controlled airspacetransition

transition /tr�n|�zʃ(ə)n/ noun an actof passing from one place, state or con-dition to anothertransition altitude

transition altitude /tr�n|�zʃ(ə)n��lttju�d/ noun altitude in the vicinityof an airport, at or below which the ver-tical position of the aircraft is controlledby reference to altitudes above meansea level � When a flight takes placeabove the transition altitude, the stand-ard pressure setting of 1013.25 mb (mil-libars) is used.transition layer

transition layer /tr�n |�zʃ(ə)n �leə/noun the airspace between the transi-tion altitude and the transition level(NOTE: The depth of this layer will nor-mally be insignificant and will neverexceed 500 ft.)transition level

transition level /tr�n|�zʃ(ə)n�lev(ə)l/ noun the lowest flight levelabove the transition altitudetransit loungetransit lounge /�tr�nzt laυnd"/noun a room where transit passengerswait for connecting flightstransit passenger

transit passenger /�tr�nzt�p�snd"ə/ noun a traveller who ischanging from one aircraft to anothertranslation

translation /tr�ns|�leʃ(ə)n/ noun 1.the movement of an object in a straightline in which every part of the objectfollows a parallel course and no rotationtakes place 2. the act of expressing the

meaning of words in one language inwords from another languagetransmissiontransmission /tr�nz |�mʃ(ə)n/ noun1. the sending of a radio signal � Thecombination of loop and sense anten-nae can determine the direction fromwhich a transmission is made. 2. a radiosignal that is transmittedtransmittransmit /tr�nz|�mt/ verb 1. to pass,to convey � As the camshaft rotates, thecam will transmit a lifting force throughrods and pivots to open the valve. � Thecharts are transmitted from one stationto another by fax. 2. to send out a radiosignal � Survival beacons transmit asignal which enables search aircraft torapidly locate survivors in the water.(NOTE: transmitting – transmitted)transmittertransmitter /tr�nz |�mtə/ noun adevice for sending out radio signals �

Although continuous wave radars oper-ate continuously, separate transmitterand receiver antennae must be used. �

Signal strength is inversely propor-tional to the distance from the transmit-ter.transparencytransparency /tr�ns |�p�rənsi/noun the condition of being transparent� Meteorological visibility gives infor-mation on the transparency of theatmosphere to a stationary groundobserver.transparenttransparent /tr�ns |�p�rənt/ adjec-tive allowing light to pass through sothat things can be seen � Aircraft win-dows and canopies are usually madefrom transparent acrylic plastic.transpondertransponder /tr�n |�spɒndə/ noun adevice in an aircraft for receiving aradio signal and automatically transmit-ting a different signal so that an air traf-fic control station can identify the air-craft � The transponder in the aircraftcomprises a transmitter and a receiver.

‘…flight trials began recently of a low-cost hand-held IFF transponder’ [Pilot]

COMMENT: The pilot sets anidentification code, or ‘squawk’,assigned by ATC, on the transponderin the aircraft.

transporttransport /�tr�nspɔ�t/ noun a systemfor moving people, freight and baggagefrom one place to another � On a large


237 tropics

transport aircraft, the safety of hun-dreds of passengers is involved.transport aircrafttransport aircraft /�tr�nspɔ�t�eəkrɑ�ft/ noun an aircraft designed tocarry ten or more passengers or theequivalent cargo and having a maxi-mum take-off weight greater than 5,670kgtraptrap /tr�p/ verb to catch and preventfrom escaping � If there is a failure ofthe pressurised air supply, the checkvalve will close and trap pressurised airin the cabin. � Smog is smoke or pollu-tion trapped on the surface by an inver-sion of temperature with little or nowind.treadtread /tred/ noun a series of patternsmoulded into the surface of a tyre toprovide grip � The risk of aquaplaningincreases as the depth of tyre tread isreduced.treattreat /tri�t/ verb 1. to behave or acttowards something or somebody in aparticular way � Pilots should treat theengine carefully, if they want to prolongits life. 2. to apply a process to some-thing in order to get a particular result �treated water water which has beenmade drinkable � heat-treated alloysalloys which have undergone a processof hardening by using heattreatmenttreatment /�tri�tmənt/ noun subjec-tion to the action of a chemical or phys-ical process � anti-corrosion treatment� heat treatmenttremblertrembler /�tremblə/ noun an auto-matic vibrator for making and breakingan electrical circuittrendtrend /trend/ noun 1. a general direc-tion or tendency � Continuous VOL-MET, which is normally broadcast on adesignated VHF (very high frequency)channel, contains current aerodromereports and trends where available. 2.an up-to-date or modern way of doingthings � Warning systems can take theform of lights, captions, and aural sig-nals, and the modern trend is to incor-porate them into a central warning sys-tem.triangletriangle /�tra�ŋ$əl/ noun a planefigure with three sides and three angles� The triangle of velocities is a vector

solution of what happens to an aircraftwhen wind causes drift. � wind1

trigger

trigger /�tr$ə/ verb to cause to oper-ate, to set off � Normally, both the cap-tain’s and first officer’s airspeed indi-cator trigger an aural warning if theairspeed limits are exceeded.trijet

trijet /�trad"et/ noun an aircraft pow-ered by three jet enginestrimtrim /trm/ noun a condition in whichan aircraft is in static balance in pitch �Trim indicators have a green band, toshow when the trim is correct for take-off. (NOTE: Some aircraft have rudderand aileron trim.) � verb to adjust trim-mers in order to get the required hands-off pitch attitude � Trim the aircraft forlevel flight.trim wheel

trim wheel /�trm wi�l/, trimmer/�trmə/ noun a wheel-shaped device,sometimes situated between the frontseats of light aircraft, to trim the aircraftby hand � The trimmer is used to easethe loads imposed on the flying controlsduring flight.trip

trip /trp/ verb to cause an electricaldevice to suddenly stop working �

Oscillating outputs from alternatorscould cause sensitive equipment to mal-function or trip.triplanetriplane /�traplen/ noun an aircraftwith three main wings fixed one abovethe othertripletriple /�trp(ə)l/ adjective consisting ofthree parts � Probes may be of single,double or triple element construction.tropical

tropical /�trɒpk(ə)l/ adjective refer-ring to the area between the parallels oflatitude 23° 26’ north and south of theequator � Tropical air moving north-wards is subjected to surface coolingand becomes increasingly stable in itslower layers.tropical stormtropical storm /�trɒpk(ə)l �stɔ�m/noun a violent wind system whichforms over tropical oceans � Tropicalstorms often dissipate when they passfrom sea to land.tropics

tropics /�trɒpks/ noun � the tropicsthe area between the parallels of lati-tude 23° 26’ north and south of theequator � Throughout the tropics and


tropopause 238

sub-tropics, the sea breeze is a regularfeature.tropopausetropopause /�trɒpəpɔ�z/ noun thelevel at which the troposphere and thestratosphere meet � The altitude andtemperature of the tropopause are ofconcern to aircrew because they affectaircraft performance.tropospheretroposphere /�trɒpəsfə/ noun thelowest region of the atmosphere � Thetroposphere is at its deepest near theequator and shallowest near the poles.troughtrough /trɒf/ noun a long area of lowbarometric pressure � Severe icing andturbulence can be experienced whenflying through a trough and the precipi-tation may be of hail, rain, snow orsleet.truetrue /tru�/ adjective referring to a cal-culation or reading which has been cor-rected for errorstrue airspeedtrue airspeed /�tru� �eəspi�d/ nounairspeed corrected for instrument andposition error in addition to altitude,temperature and compressibility errorstrue altitudetrue altitude /�tru� ��lttju�d/ nounreal or actual height above sea leveltrue bearingtrue bearing /�tru� �beərŋ/ nounbearing with reference to true north, notmagnetic northtrue degreestrue degrees /�tru� d |�$ri�z/ noundegrees of direction measured from truenorth, not magnetic north. Also calleddegrees true. Symbol °Ttrue northtrue north /�tru� �nɔ�θ/ noun thedirection towards north pole along ameridian through the observertubetube /tju�b/ noun a long, hollow cylin-drical device for holding or carryingfluids � A liquid-type fire detector con-sists of a tube and expansion chamberfilled with liquid.tubingtubing /�tju�bŋ/ noun tubes in gen-eral � hydraulic tubingtubulartubular /�tju�bjυlə/ adjective refer-ring to something which is shaped likea tube � Diagonal members can be ofangle section, box spar or tubular inshape.tunetune /tju�n/ verb 1. to set a system atits optimum point by careful adjustment� The engine has not been properly

tuned. 2. to adjust to the particular fre-quency of the required signal � The RBIshows the bearing of the tuned radiobeacon with reference to the aircraft’sheading.tunertuner /�tju�nə/ noun a part whichallows the operator to select the partic-ular frequency of the required signal �

The tuner reduces interference.turbineturbine /�t%�ban/ noun a rotary motoror engine formed of a wheel driven by aflow of air or gasturbo-turbo- /t%�bəυ/ prefix turbineturbochargerturbocharger /�t%�bəυ |�tʃɑ�d"ə/noun a supercharger driven by a turbinepowered by exhaust gases � The turbo-charger significantly increases enginepower.turbofanturbofan /�t%�bəυf�n/ noun a jetengine in which most of the thrust isproduced by air, accelerated by a largefan, which does not pass through thecombustion chamber of the engine �

The Airbus A340 is powered by fourCFM56 turbofans. (NOTE: The US termis fanjet.)

COMMENT: Turbofan engines aremuch quieter than older turbojets andmake a characteristic sound when inoperation. The fan can be clearly seenin the front part of the engine. Modernairliners use turbofan enginesproduced by major manufacturerssuch as Rolls Royce, CFM or Pratt andWhitney.

turbojetturbojet /�t%�bəυd"et/ noun a jetengine which includes a turbine-drivencompressor for the air taken into theengine � The de Havilland Comet wasthe world’s first turbojet commercialtransport aircraft.

COMMENT: In recent years turbofanengines have taken over from turbojetengines. Frank Whittle (1907–96) wasan English engineer and RAF officerwho invented the turbojet aircraftengine. Whittle developed a jet aircraftby 1941 and the first military jetaircraft, the Gloster Meteor, becameoperational in 1944.

turbopropturboprop /�t%�bəυprɒp/, turbopro-peller /�t%�bəυprə|�pelə/ noun a turbo-jet engine in which the turbine alsodrives a propeller � The turboprop


239 tyre

engine is often used in transport air-craft.

COMMENT: Turboprop aircraft areefficient at lower speeds than turbojetaircraft and are often used for short-haul operations.

turboshaftturboshaft /�t%�bəυʃɑ�ft/ noun anengine similar to a turboprop engine,except that it is used primarily in heli-coptersturbulenceturbulence /�t%�bjυləns/ noun anirregular motion of the atmosphereturbulentturbulent /�t%�bjυlənt/ adjectivereferring to the irregular motion of theatmosphere � When flying in turbulentair conditions, an aircraft is subjectedto upward and downward gust loads.turnturn /t%�n/ noun 1. an angular changein track � a 180° turn � The autopilotmay be engaged during a climb ordescent but not usually in a turn. 2. asection of a wire which is wound 360°around a centre � The voltage in eachwinding is directly proportional to thenumber of turns in each winding. � verb1. to make an angular change in track �

turn right � Turn to the west. 2. to rotate� The crankshaft turns through 720° forevery cycle of four strokes. � turn theknob rotate the knob or control 3. � toturn (in)to to change state � As itdescends into warmer air, snow turnsinto rain. 4. to find a page, section, pas-sage, etc., in a book � Turn to page 64.� in turn 1. for its or their part � Dragmust be overcome with thrust, whichrequires engines, which in turn con-sume fuel. 2. one after the other � Turnoff the magnetos in turn to check theirserviceability.turnaroundturnaround /�t%�nə|�raυnd/ noun USsame as turnroundturn coordinatorturn coordinator /�t%�n kəυ |

�ɔ�dnetə/ noun an instrument thatshows the pilot if the aircraft is in coor-dinated flight or if it is slipping or skid-dingturn offturn off /�t%�n �ɒf/ verb 1. to switch anelectrical device or system ‘off’ � Whencarrying out engine checks, turn off themagnetos in turn to check their service-ability. 2. to stop the flow of somethingby using a valve � Turn off the fuel.

turn onturn on /�t%�n �ɒn/ verb 1. to switch anelectrical device or system ‘on’ � Canyou turn the light on or turn on thelight? 2. to start the flow of somethingby using a valve � Turn on the fuel.turnroundturnround /�t%�nraυnd/ noununloading, loading and preparing anaircraft for another flight and the timetaken to do this (NOTE: The word turna-round is preferred in US English.)twin engine aircrafttwin engine aircraft /�twn �end"n�eəkrɑ�ft/, twin-engined aircraft/�twn �end"nd �eəkrɑ�ft/ noun anaircraft with two identical enginestwist

twist /twst/ verb to turn againstresistance � Centrifugal, bending andtwisting forces act on a propeller duringflight.TWR

TWR abbreviation aerodrome controltowertypetype /tap/ noun 1. a sort or kind �

Temperature and oil pressure are criti-cal to any type of system. 2. a class ofthings having shared characteristics �

The type of undercarriage fitted to anaircraft is governed by the operatingweight. � type of aircraft or aircrafttype all aircraft of the same basicdesigntype certificate

type certificate /�tap s%�|�tfkət/noun a document issued by an aviationauthority which indicates that thedesign of a certain aircraft, engine etchas been approvedtype certificate data sheet

type certificate data sheet noun adocument associated with a type certif-icate, giving information about why thecertificate has been granted and generalinformation about the design which hasbeen approved. Abbreviation TCDStype rating

type rating /�tap �retŋ/ nounauthorisation, usually entered on alicence, which allows the pilot to fly aparticular aircraft typetypical

typical /�tpk(ə)l/ adjective 1. nor-mal, standard � a typical fuel system astandard type of fuel system 2. repre-sentative of a particular class of things �The Piper Archer is a typical single-engine light aircraft.tyre

tyre /�taə/ noun a rubber covering fora wheel (NOTE: The US spelling is tire.)


tyre creep 240tyre creep

tyre creep /�taə kri�p/ noun thegradual rotation of the tyre in relation tothe wheel, caused by landing � to con-vert magnetic bearing into true bearingit is necessary to apply magnetic varia-tion at the point at which the bearingwas taken

COMMENT: Tyre creep can lead todamage to the tyre valve andsubsequent unwanted and possiblydangerous deflation of the tyre.

tyre pressure

tyre pressure /�taə �preʃə/ nounthe air pressure in a tyre � maximumallowable tyre pressure


UUAR

UAR abbreviation upper air routeUAS

UAS abbreviation upper air spaceUHF

UHF abbreviation ultra high frequencyUIR

UIR abbreviation upper air regionUK

UK abbreviation United Kingdomultimate

ultimate /��ltmət/ adjective final,from which no further advance can bemade � To determine the ultimate loadwhich a structure must be capable ofwithstanding, a multiplier, called theultimate factor of safety is used. � Theultimate responsibility for safety restswith the crew.ultra-

ultra- /�ltrə/ prefix beyondultra high frequency

ultra high frequency /��ltrə ha�fri�kwənsi/, ultra high frequencyband /��ltrə ha �fri�kwənsi �b�nd/noun a radio frequency range between300 MHz and 3000 MHz. AbbreviationUHFultralight

ultralight /��ltrəlat/ noun a smallsingle-seat or two-seat aircraft con-structed of light materials and poweredby a small motor, flown mainly for rec-reationultrasonic

ultrasonic /��ltrə|�sɒnk/ adjectivereferring to frequencies in the range of20,000 Hz which cannot be heard by thehuman earultrasonic inspection

ultrasonic inspection/��ltrəsɒnk n |�spekʃ(ə)n/ noun anon-destructive inspection of materialsusing extremely high frequency vibra-tions. Also called ultrasonic detectionultraviolet

ultraviolet /��ltrə |�vaələt/ adjectivereferring to or occurring in the invisiblepart of the light spectrum beyond violet.Abbreviation UV � ultraviolet radia-

tion the invisible part of the light spec-trum beyond violetunaccompaniedunaccompanied /��nə |�k�mpənid/adjective � unaccompanied baggagebaggage that travels on a different flightfrom the passenger who owns it. �

accompanieduncontrolled airspaceuncontrolled airspace/��nkəntrəυld �eəspes/ noun airspacein which air traffic control does not pro-vide a service and in which an ATCclearance is not required to fly � Whilefirst learning to handle an aircraft, stu-dent pilots fly in uncontrolled airspace.(NOTE: Pilots must still follow certainrules when flying through uncontrolledairspace.)uncoordinated flightuncoordinated flight noun flight,especially during turns, in which thehorizontal and vertical forces acting onthe aircraft are out of balance. This canresult in the aircraft going into a slip ora skid.undercarriageundercarriage /��ndək�rd"/ nounthe landing gear of an aircraft � Toreduce the effect of drag by fixed under-carriages a retractable type of under-carriage was introduced. (NOTE: Theundercarriage is often called the land-ing gear or simply gear.)

COMMENT: The main landing gear arenearest the aircraft’s centre of gravity.Main landing gear are designed towithstand a greater landing shock thanthe nose wheel or tail wheel andconsequently should make contactwith the surface first when landing.

undercarriage assemblyundercarriage assembly/��ndək�rd" ə |�sembli/ noun wheels,struts and linkages which make up thecomplete unit


undergo 242undergoundercarriage down and locked/��ndək�rd" �daυn ən �lɒkd/ nounconfirmation that the undercarriage issecure in preparation for landingundergoundergo /��ndə|�$əυ/ verb to experi-ence, to pass through a process � Whenwater changes from vapour to liquid,energy is released into the atmospherewhich is thus warmed, although thewater itself does not undergo a changeof temperature. (NOTE: undergoing –underwent – has undergone)underlyingunderlying /��ndə|�laŋ/ adjective 1.being under � Thermal modificationsoccur when the temperature of theunderlying surface differs from that ofthe source region. 2. forming the basisof a theory or principle � The principleunderlying the construction of a mer-cury barometer has not changed since1643, when Torricelli first demon-strated that the atmosphere has weight.undershootundershoot /��ndə |�ʃu�t/ verb toland before, or in front of the intendedtarget � Because of the strong wind, thestudent pilot undershot the runway andlanded before the runway threshold.undersideunderside /��ndəsad/ noun the sur-face underneath something � Theunderside of the wing should be care-fully inspected for damage or leaks.undertakeundertake /��ndə |�tek/ verb to do �

In light aircraft, pilot/passenger com-munication can be satisfactorily under-taken verbally on a one to one basis.(NOTE: undertaking – undertook –has undertaken)undulatingundulating /��ndjυletŋ/ adjectiverising and falling in gentle slopes �

Flight over undulating terrain willresult in changing indications of air-craft height on the indicator of the radioaltimeter.uniformuniform /�ju�nfɔ�m/ adjective thesame, not varying in quality, dimen-sions, etc. � An engine should be run atlow r.p.m. (revolutions per minute) afterflight to allow engine components tocool to a uniform temperature.uniqueunique /ju�|�ni�k/ adjective the oneand only of its sort, having no like orequal � The pulse coded message con-tains a unique 4-number identification.

unitunit /�ju�nt/ noun 1. a quantity oramount used as a standard, an acceptedmeasurement � The internationallyagreed unit of pressure is the millibar. �The higher the sun is in the sky, themore intense is the radiation per unitarea. 2. a person, group or device, com-plete in itself � The operation of flyingcontrols is by means of self-containedpower flying control units (PFCUs).universaluniversal /�ju�n |�v%�s(ə)l/ adjectiveaffecting all or everybody � The use offly-by-wire systems in airliners wasdelayed to allow thorough developmentand encourage universal acceptance ofthe new technology. � CoordinatedUniversal Timeunloadunload /�n|�ləυd/ verb to remove aload from an aircraft � It took threehours to unload the aircraft.unloading pointunloading point /�n |�ləυdŋ pɔnt/noun the place where an aircraft isunloaded � After taxiing, a marshallermarshals the aircraft to the disembar-kation and unloading point.unsaturatedunsaturated /�n|�s�tʃəretd/adjective � unsaturated air air thatdoes not contain the maximum amountof water vapour for its temperatureunserviceableunserviceable /�n|�s%�vsəb(ə)l/adjective not operative � The aircraftcannot be flown because the radio isunserviceable. (NOTE: It is often abbre-viated in spoken English as U (you) S(ess).)unstickunstick /�n |�stk/ (informal ) verb tocause an aircraft to take off, or take offin an aircraft � noun a take-off in an air-craftupdateupdate /�p |�det/ verb to bring up todate, to add the latest information tosomething � Forecasts are updated andreissued every four hours.updraftupdraft /��pdrɑ�ft/ noun US same asupdraughtupdraughtupdraught /��pdrɑ�ft/ noun a risingcurrent of air � In cumulonimbusclouds, there are updraughts of tremen-dous force. Opposite downdraught(NOTE: It is written updraft in US Eng-lish.)upliftuplift /��plft/ noun the lifting of air bysurface features � Thunderstorms are


243 UV

triggered off by convection and/or oro-graphic uplift.upperupper /��pə/ adjective 1. at high alti-tude � upper air � upper winds � Inmodern meteorological practice, upperair analysis and the construction ofcontour charts is carried out by compu-ter. 2. top. Opposite lower � the uppersurface of the wing the surface of thewing facing upwards, as opposed to theundersideupper air chartupper air chart /��pə �eə �tʃɑ�t/noun a chart showing airflow patternand distribution of temperatures at spe-cific altitudes above about 10,000 feetupper air routeupper air route /��pə �eə �ru�t/ nouna route above FL245, approximately24,500 ft. Abbreviation UARupper airspaceupper airspace /��pə �eəspes/noun the airspace above FL245,approximately 24,500 ft. AbbreviationUASupper information regionupper information region nounairspace which covers the same geo-graphical area as a flight informationregion but above 24,500 ft. Abbrevia-tion UIRupwardupward /��pwəd/ adjective moving ordirected up � As the aircraft acceleratesdown the runway, the forces on the wingtips and wing surfaces start reversingdirection and instead of being onlydownward forces of weight, theybecome upward forces of lift. (NOTE: InUS English, upward is used as anadjective and as an adverb.)upwardsupwards /��pwədz/ adverb towardsthe top � Heat is transferred from theEarth’s surface upwards by convection.Opposite downwardsupwindupwind /�p|�wnd/ adverb against thewind � The glider was released from the

aero-tow 3 miles upwind of the airfield.Opposite downwindurgencyurgency /�%�d"ənsi/ noun importanceor need for prompt or fast action �

Warnings, cautions and advisory mes-sages are displayed only when neces-sary and are colour coded to communi-cate the urgency of the fault to the flightcrew.USAUSA, US abbreviation United States ofAmericausableusable /�ju�zəb(ə)l/ adjective capableof being used � On receiving the evacu-ate order, cabin crew must assess iftheir exits are usable.usageusage /�ju�sd"/ noun the act of usingsomething, consumption � Fuel flightplanning combines navigation datawith fuel usage.useuse noun /ju�s/ the act of using some-thing, or the state of being used � Itmust be ensured that smoke masks areavailable for use by employees withinthe aircraft. � runway in use runwaycurrently being used for take-offs andlandings � verb /ju�z/ to put somethingto work for a purpose � Gas turbineengines use low viscosity synthetic oil.UTCUTC abbreviation Coordinated Univer-sal Timeutilisationutilisation /�ju�tla|�zeʃ(ə)n/, utili-zation noun the act of making use of �

Integral tanks are now favoured for air-craft owing to the high utilisation ofspace and reduction in weight.utiliseutilise /�ju�tlaz/, utilize verb tomake use of � The most common type ofbarograph is one which utilises ananeroid capsule mechanically con-nected to a pen.UVUV abbreviation ultraviolet


Vvacuum

vacuum /�v�kju�m/ noun a spacecompletely empty of everything includ-ing air � If the fuel tank vent pipe isblocked, a vacuum will form in the tankand fuel flow to the engine will berestricted.valid

valid /�v�ld/ adjective 1. having offi-cial force or effect � All passengersshould have valid passports. 2. worthtaking seriously, acceptable because itis true or well-based � Significantweather charts use abbreviations andsymbols to illustrate en route weatherphenomena and are valid for a specifiedtime. � a valid assumption a well-based suppositionvalidity

validity /və |�ldti/ noun the state ofbeing valid � the period of validity of avisa � Aerodrome forecasts included inVOLMET should have a validity periodof 9 hours.valley

valley /�v�li/ noun an area of low-lying land between mountains or hills �An example of a valley wind is the Mis-tral.value

value /�v�lju�/ noun 1. a quantityshown as a number � Deviation is not aconstant value but varies from one air-craft to another. 2. the quality of beinguseful or desirable � the value of doingsomething the usefulness or worth ofdoing somethingvalve

valve /v�lv/ noun a mechanicaldevice for controlling the flow of a fluidvalve overlap

valve overlap /�v�lv �əυvəl�p/noun the period when both the exhaustand inlet valves are open together, withthe exhaust valve closing and the inletvalve opening

valve seatvalve seat /�v�lv si�t/ noun anangled ring in the cylinder head onwhich the poppet valve sits when closedvanevane /ven/ noun a flat surface actedon by the wind or an airflow � A centrif-ugal compressor consists of a disc onwhich is formed a number of radiallyspaced vanes.vaporvapor /�vepə/ noun US same asvapourvaporisevaporise /�vepəraz/, vaporize verbto turn into vapour � Water vaporiseswhen heated.vapourvapour /�vepə/ noun the gaseousform of a liquid � Over desert areas, thelack of water vapour in the atmosphereproduces cold nights. (NOTE: It is alsowritten vapor in US English.)vapour lockvapour lock /�vepə lɒk/ noun ablockage of fuel flow from a tankcaused by a bubble of vapour at a highpoint in the pipelinevapour trailvapour trail /�vepə trel/ noun a vis-ible trail of condensed vapour leftbehind by an aircraft flying at high alti-tudevariablevariable /�veəriəb(ə)l/ adjectivechanging or changeable � Winds aremore variable in the northern hemi-sphere than in the southern hemisphere.variable geometryvariable geometry /�veəriəb(ə)ld"i� |�ɒmətri/ noun technology whichallows the angle between wing andfuselage to be altered to give a more orless swept wing for better high-speedand low-speed flight characteristicsvariable-geometryvariable-geometry /�veəriəb(ə)ld"i|�ɒmətri/ adjective referring to anaircraft with hinged wings that canmove backwards or forwards during


245 venturi

flight (NOTE: The wings are swept backto give low drag in supersonic flight andare moved forwards for takeoff andlanding.)variable pitch propellervariable pitch propeller/�veəriəb(ə)l ptʃ prə |�pelə/ noun apropeller with a mechanism to changethe blade angle, to suit flight conditionsvariable-sweepvariable-sweep /�veəriəb(ə)l�swi�p/ adjective same as variable-geometryvariationvariation /�veəri|�eʃ(ə)n/ noun 1. achange or the amount of a change 2. theangular difference between magneticnorth and true north, which is measuredin degrees and is named east or westaccording to whether the north-seekingend of a freely suspended magnet lies tothe east or to the west of the true merid-ian at that point � variation east, mag-netic least: variation west, magneticbest a mnemonic to help somebodyremember whether to add or subtractvariationvarietyvariety /və |�raəti/ noun a lot of differ-ent things � Display units provide awide variety of information relevant toengine and other automated systemsoperation.variometervariometer /�veəri |�ɒmtə/ noun aninstrument used for measuring the rateof climb of an aircraft such as a glidervaryvary /�veəri/ verb to change, to be dif-ferent � The tropopause over the UKcan vary between 25,000 feet and45,000 feet according to whether thecountry is covered by a polar or tropi-cal air mass.VASIVASI abbreviation visual approachslope indicatorvastvast /vɑ�st/ adjective large, immense,huge � the vast majority most � thevast majority of peopleVCRVCR abbreviation visual control roomVDFVDF abbreviation very high frequencydirection-findingvectorvector /�vektə/ noun 1. a quantitywith magnitude and direction indicatedby a line of a given length, representingmagnitude and specific direction � Thetriangle of velocities is a vector solutionof what happens to an aircraft whenwind causes drift. 2. a heading given to

a pilot to provide navigational guidanceby radar � Wind velocity is indicated bya vector, identified by a single arrow,pointing in the direction the wind isblowing towards.veer

veer /və/ noun the shifting of the windin a clockwise direction in the northernhemisphere � The passing of a weathertrough is marked by a sharp veer in thedirection of the wind. � verb 1. tochange in a clockwise direction in thenorthern hemisphere � Winds veer andincrease with height ahead of a warmfront. Opposite back 2. to change direc-tion, especially as in an uncontrolledmovement � The aircraft veered off therunway into the grass.velocity

velocity /və|�lɒsti/ noun the rate ofchange of position in a given directionwhich is composed of both speed anddirection � wind velocity � The anemo-graph gives a continuous recording ofwind velocity which is displayed on achart and reveals gusts, squalls andlulls. � trianglevent

vent /vent/ noun a hole serving as aninlet or outlet for a fluid, usually a gassuch as air � During the pre-flightinspection, check that the fuel tank ventpipe is not blocked. � The vent/pressur-isation system must allow for the pas-sage of air whenever a fuel tank is refu-elled or defuelled or the aircraft climbsor descends.ventilate

ventilate /�ventlet/ verb to cause airto pass in and out freely � The waterseparator is installed downstream ofthe cold air unit to extract a percentageof free moisture from the air, which sub-sequently ventilates and pressurises thecabin.ventilation

ventilation /�vent|�leʃ(ə)n/ nounfree circulation of air in and out � Aconstant supply of air for ventilationpurposes is always available from theair conditioning system.venturi

venturi /ven |�tjυəri/, venturi tubenoun a tube which narrows at the cen-tre, a choke tube � When the tempera-ture of the air passing through the car-burettor is reduced below O°C(Celsius), any moisture in the air forms


verification 246

into ice and builds up on the venturi andthrottle valve.verification

verification /�verf|�keʃ(ə)n/ nounan act or instance of establishing thetruth or validity of something � Thedocument required verification.versus

versus /�v%�səs/ preposition against,as compared with � The diagram illus-trates typical strength properties byplotting applied stress versus resultingstrain.vertical

vertical /�v%�tk(ə)l/ adjective at rightangles to the Earth’s surface or toanother line or plane � Beams can beadditionally stiffened in a downwarddirection by vertical and diagonalmembers. � Height is defined as the ver-tical distance of a level, point or object,considered to be a point, from a speci-fied datum. � noun a vertical line orplane � The hot rod ice detector headconsists of an aluminium alloy oblongbase on which is mounted a steel tubedetector mast, angled back to approxi-mately 30° from the vertical.vertical axis

vertical axis /�v%�tk(ə)l ��kss/noun 1. an imaginary line runningthrough the fuselage at the centre ofgravity from top to bottom, aroundwhich the aircraft rotates when it yaws� The rudder is a control surface on thefin which rotates the aircraft about itsvertical axis to produce yaw. � yaw 2. avertical reference line (Y axis) of agraph � The vertical axis shows enginepower available.vertically

vertically /�v%�tk(ə)li/ adverb in avertical position � The aircraft pitchedup vertically.vertical speed indicator

vertical speed indicator/�v%�tk(ə)l �spi�d �ndketə/ noun aflight instrument which indicates therate of climb and descent. AbbreviationVSIvertical stabiliser

vertical stabiliser /�v%�tk(ə)l�steblazə/ noun same as finvery high frequency

very high frequency /�veri ha�fri�kwənsi/, very high frequencyband /�veri ha �fri�kwənsi �b�nd/noun the radio frequency rangebetween 30 MHz and 300 MHz. Abbre-viation VHF

very high frequency omni-directional radio rangevery high frequency omni-directional radio range /�veri ha�fri�kwənsi �ɒmnidarekʃən(ə)l�rediəυ �rend"/ noun full form ofVORvesselvessel /�ves(ə)l/ noun a boat or ship �When flying over the sea you must notfly closer than 500 feet to a vessel.VFRVFR abbreviation visual flight rulesVHFVHF abbreviation very high frequencyviavia /�vaə/ preposition by way of � Theflight is from Cairo to Paris via Rome. �After heating, the air passes into thecabin via a chamber through whichcold air also flows.vibratevibrate /va |�bret/ verb to move rap-idly and continuously backwards andforwards � Turbine blades in the aver-age jet engine vibrate at frequencies of1 million per minute.vibrationvibration /va |�breʃ(ə)n/ noun arapid and continuous movement �

According to the pilot, engine vibrationwas detected in engine number one.vice versavice versa /�vasə �v%�sə/ adjectivethe other way around � when enginedemand is high, fuel pressure tends tobe low and vice versa when the enginedemand is low, fuel pressure tends to behighvicinityvicinity /və|�snti/ noun the areanearby � After an emergency evacua-tion, passengers should be directed tomove away from the vicinity of the air-craft quickly. � in the vicinity of theairport near the airportviewview /vju�/ noun 1. what you are ableto see from a particular place � Cabincrew must have a clear view of theaisles from their stations. 2. a picture ofsomething presented in a particular way� a cross-sectional view of an aerofoil3. a personal opinion � He expressedstrong views on the subject of airportsecurity. 4. � with a view to with theintention of � She wrote the report witha view to improving in-flight services. �in view of because of � In view of thepoor weather conditions, the flight willbe delayed.violateviolate /�vaəlet/ verb 1. to enterwithout permission � The aircraft vio-lated a danger area. 2. to break rules or


247 viz

regulations � By not wearing a cap, thecadet is violating the dress code.violent

violent /�vaələnt/ adjective withgreat force � Flying through atmos-pheric dust causes the airframe to buildup a static electrical charge and theassociated discharges can be violent.VIP

VIP abbreviation very important personvirtually

virtually /�v%�tʃuəli/ adverb almost �

Resistance to alternating currentremains virtually constant and is inde-pendent of frequency.viscosity

viscosity /v |�skɒsti/ noun a liquid’sinternal resistance to flowing � Exces-sive oil temperatures are dangerous, asthe oil viscosity is reduced and inade-quate bearing lubrication results.visibility

visibility /�vz|�blti/ noun the abilityto see unlighted objects by day andlighted objects by night, subject toatmospheric conditions � Measurementof visibility by day is made by directobservation of objects at known dis-tances and is therefore an estimatedvalue. � poor visibility a situation inwhich things cannot be seen clearly, e.g.because of fog, mist or smokevisibility-by-day values

visibility-by-day values/�vzəblti ba �de �v�lju�z/ nounvalues which indicate how easily seenan object is in a horizontal line from anobserver in daylight conditionsvisible

visible /�vzb(ə)l/ adjective that canbe seen � When the undercarriage isselected down it may be visible from thecrew compartment, but it is not usuallypossible to tell if it is securely locked. �

If the sun is seen through cumulus cloudit will be clearly visible.vision

vision /�v"(ə)n/ noun 1. the power ofseeing, the ability to see � Lightning atnight may cause temporary loss ofvision. 2. what you are able to see � Inlow wing aircraft, downward visionmay be limited by the airframe.visual

visual /�v"υəl/ adjective referring toseeing � The instrument landing systemis to provide guidance in the horizontaland vertical planes to an aircraft onfinal approach into a position fromwhich a safe visual landing can bemade.

visual approach slope indicator

visual approach slope indicator/�v"υəl ə |�prəυtʃ �sləυp �ndketə/noun an arrangement of red and whitelights on each side of the runway touch-down point to give the pilot informationabout the plane’s height on finalapproach. Abbreviation VASIvisual control room

visual control room /�v"υəl kən|

�trəυl �ru�m/ the control room in thetower at an airport. Abbreviation VCRvisual examinationvisual examination /�v"υəl $ |

�z�m |�neʃ(ə)n/ noun a close observa-tion or inspection with the eyes. Alsocalled visual inspectionvisual flight rules

visual flight rules /�v"υəl �flat�ru�lz/ plural noun rules set down by anauthority for flight in visual conditions,regarding such things as flight visibilityand distance from cloud. AbbreviationVFR. � special VFR flight

COMMENT: Particular requirements forVFR depend on the type of airspace,time of day, and height above terrain.

visual indicationvisual indication /�v"υəl �nd|

�keʃ(ə)n/ noun something which isseen and which suggests a more seriouscause, e.g. a warning lamp � Distortedwing panels are often a visual indica-tion of structural damage to the air-frame.visual meteorological conditionsvisual meteorological condi-tions /�v"υəl �mi�tiərəlɒd"k(ə)lkən |�dʃ(ə)nz/, visual meteorologicalconditions criteria /��pə �eə �tʃɑ�t/plural noun all the factors which definethe limits of flying in visual meteoro-logical conditions. Abbreviation VMCvisual warning

visual warning /�v"υəl �wɔ�nŋ/noun a warning that can be seen asopposed to a audible warning that canbe heardvital

vital /�vat(ə)l/ adjective extremelyimportant � Verbal commands from thecrew are vital at all times but particu-larly so if smoke restricts cabin visibil-ity. � Accurate measurements of atmos-pheric pressure and the rate of changeof pressure are of vital interest to themeteorological forecaster.viz

viz /vz/ adverb namely, in otherwords, that is to say � There are twotypes of inverter, viz rotary and static.


VMC 248VMCVMC abbreviation visual meteorologi-cal conditionsVneVne abbreviation never-exceed speedvolatilevolatile /�vɒlətal/ adjective describesa liquid which easily changes into a gasor vapour � To aid starting in coldweather, more volatile fuels can be usedvolatilityvolatility /�vɒlə|�tlti/ noun the easewith which a liquid changes into a gasor vapour � With kerosene-type fuels,the volatility is controlled by distillationand flash point, but with the wide-cutfuels it is controlled by distillation andthe Reid Vapour Pressure test.VOLMETVOLMET /�vɒlmet/ noun a routineground-to-air broadcast of meteorolog-ical information � The meteorologicalOperational Telecommunications Net-work Europe (MOTNE) is provided forthe exchange of meteorological infor-mation needed by meteorologicaloffices, VOLMET broadcasting sta-tions, air traffic service units, operatorsand other aeronautical users.volplanevolplane /�vɒlplen/ noun a glidetowards the ground in an aircraft withthe engine turned off � verb to glidetowards the ground in an aeroplane withthe engine turned offvoltvolt /vəυlt/ noun the SI unit of electri-cal potential � The system requires apower supply of either 115 volts AC(alternating current), 28 volts DC(direct current), or both. AbbreviationVvoltagevoltage /�vəυltd"/ noun electricalforce measured in volts � As aninstalled battery becomes fully chargedby the aircraft generator, the batteryvoltage nears its nominal level and thecharging current decreases.volumevolume /�vɒlju�m/ noun 1. theamount of space occupied by a solid, aliquid or a gas � If the pressure of agiven mass of gas is maintained con-stant, the volume of gas increases as its

temperature is increased. 2. the loud-ness of a transmission � turn down thevolume to make the sound less loud byadjusting the volume controlvolume control

volume control /�vɒlju�m kən |

�trəυl/ noun a knob used to adjust thesound by making it louder or less loudVOR

VOR noun a navigational aid based onthe ground, to help the pilot establishthe bearings of the aircraft. Full formvery high frequency omni-direc-tional radio range

COMMENT: The VOR projects 360radials which can be followed to fly aparticular path over the ground. VORsoperate on VHF frequencies between108.0 to 177.95 MHz.

VOR bearing

VOR bearing /�vi� əυ �ɑ� �beərŋ/noun the direction of the VOR transmit-ter relative to the aircraft measured indegreesVORTAC

VORTAC /�vɔ�t�k/ noun a systemthat combines VOR and TacanVSI

VSI abbreviation vertical speed indica-torV/STOL

V/STOL /�vi�stɒl/ noun 1. a systemused by some aircraft that allows themto take off and land vertically or on ashort runway 2. an aircraft that is able totake off and land vertically or on a shortrunway. Full form vertical and shorttakeoff and landingVTOLVTOL /�vi�tɒl/ noun 1. a system usedby some aircraft that allows them totake off and land vertically 2. an aircraftthat is able to take off and land verti-cally. Full form vertical takeoff andlandingvulnerable

vulnerable /�v�ln(ə)rəb(ə)l/ adjec-tive unprotected and liable to attack ordamage � Some engines still retain thecentrifugal type of compressor becauseit is simple, comparatively cheap tomanufacture, robust in constructionand less vulnerable to damage.


WW

W abbreviation westWAAS

WAAS noun a US navigation systemwhich processes and improves datafrom GPS satellites to provide locationinformation. Full form Wide Area Aug-mentation System (NOTE: The Euro-pean equivalent is EGNOS.)wake turbulence

wake turbulence /�wek�t%�bjυləns/ noun the disturbance ofthe air remaining after the passage of anaircraftwallwall /wɔ�l/ noun the side � There is afilm of oil between the piston and cylin-der wall.warm frontwarm front /�wɔ�m �fr�nt/ noun anadvancing mass of warm air movingover a mass of cooler airwarnwarn /wɔ�n/ verb to give notice of pos-sible danger � A light illuminates towarn the crew.

‘…ultrasonic technology whichautomatically warns pilots of ice build-upon aircraft may soon be approved forgeneral use by carriers’ [FlightInternational 16–22 July 1997]

warningwarning /�wɔ�nŋ/ noun notice ofpossible danger � adjective givingnotice of possible danger � The mainpower plant fire detection systemshould contain an audible warningdevice to supplement the visual indica-tion.warning indicator

warning indicator /�wɔ�nŋ�ndketə/ noun an indicator whichgives notice of a possible problemwhich may require some action. � VASIwarning light

warning light /�wɔ�nŋ lat/ noun asmall light, often red, which informs ofa possible danger by lighting up � At 5

knots above stalling speed, a warninglight on the instrument panel will flash.washroomwashroom /�wɒʃru�m/ noun same astoilet 2wastewaste /west/ noun something whichcan no longer be used � A smoulderingfire in a toilet waste container or wastedisposal bin could become very activedue to pressure changes during descent.water-tightwater-tight /�wɔ�tə tat/ adjectivethat does not leak water or other fluidwattwatt /wɒt/ noun the SI unit of meas-urement of electrical power � The workdone by an electrical circuit or thepower consumed is measured in watts.wavewave /wev/ noun 1. the motion bywhich heat, light, sound or electric cur-rent is spread � The speed of propaga-tion of radio waves is faster over seathan over land. 2. a mass of water mov-ing across the surface of a lake or thesea, rising higher than the surroundingwater as it moves � Wind speedsincrease with height, the speed of thewind at the crest of a wave being thegreatest.waveformwaveform /�wevfɔ�m/ noun theshape of a repetitive wave � A cycle isone complete sequence of the wave-form, from any point, to the same value360° later.wavelengthwavelength /�wevleŋθ/ noun thedistance from the highest point of onewave to the highest point of the next �

Short wavelength permits sharperbeams for direction finding and moreefficient reflections.waveoffwaveoff /�wevɒf/ noun a signal orinstruction to an aircraft that it shouldnot land


waypoint 250waypointwaypoint /�wepɔnt/ noun a prede-termined position on a route, used formonitoring flight progress or for navi-gating around controlled airspace.Abbreviation WPweakweak /wi�k/ adjective 1. not strong � aweak radio signal 2. overdiluted withwater or air � weak mixture a fuel/airmixture in which there is more air thanusual � Excessive cylinder head tem-peratures could be caused by prolongeduse of a weak mixture, especially athigh altitude. � weak solution a mix-ture of water and some other substancein which the amount of water is morethan usualweakenweaken /�wi�kən/ verb to make weak� Inflation of the de-icer boot weakensthe bond between the ice and de-icerboot surfaces.wearwear /weə/ noun damage or loss ofquality by use � Mishandling of aero-engines during operation can causeconsiderable damage and wear whichcan shorten the life of the engine. � verb1. to become damaged or to lose qualitybecause of use � The more the brakesare used, the more they wear. 2. to haveon the body � The nature of modern jettransport does not require the pilot towear an oxygen mask.weatherweather /�weðə/ noun the conditionsof atmospheric temperature, pressure,wind, moisture, cloudiness, precipita-tion and visibility � Generally speak-ing, weather conditions can bedescribed as light, moderate or severedepending on the intensity of the condi-tions. � forecast weather predictedweather, not actual weatherweathercockweathercock /�weθəkɒk/ verb totend to turn in the direction of the windweather reportweather report /�weðə r|�pɔ�t/noun an official account of weatherconditionswebweb /web/ noun the main verticalmember of a beam � The web connect-ing the upper and lower flanges of thebeams must be rigid enough to with-stand direct compressive loads withoutbuckling.weighweigh /we/ verb to measure howheavy something is � A given quantity

of lead weighs more than the samequantity of aluminium.weight

weight /wet/ noun the force withwhich a body is drawn towards the cen-tre of the Earth � Carry-on baggage islimited by regulations as to size andweight and items in excess of thisshould be stowed in the hold.westwest /west/ noun 1. a compass pointon the mariner’s compass 270° clock-wise from due north and directly oppo-site east � In Europe, snow occurs morefrequently in the east than in the west. 2.the direction of the setting sun � adjec-tive 1. referring to areas or regions lyingin the west 2. the western part of a coun-try � West Africa � adverb towards thewest � The aircraft was flying west.westbound

westbound /�westbaυnd/ adjectivetravelling towards the west � a west-bound flightwesterlywesterly /�westəli/ adjective 1. situ-ated towards the west 2. blowing orcoming from the west � A westerly windis blowing. 3. moving to the west ortowards the west � He should fly in awesterly direction. � noun a wind whichblows or comes from the west � Tem-perate westerlies occur on the side ofthe sub-tropical anti-cyclonic beltswhich is remote from the equator.westernwestern /�westən/ adjective situatedin the west � Western Europewestwardwestward /�westwəd/ adjectivegoing towards the west � adverb USsame as westwardswestwards

westwards /�westwədz/ adverbtowards the west � Flying eastwards orwestwards for long periods of timeaffects sleep patterns.west wind

west wind /�west �wnd/ noun awind blowing from or coming from thewest (NOTE: A wind is named after thedirection it comes from.)wheelwheel /wi�l/ noun a circular, rotating,load-carrying part between the tyre andaxle, or the whole wheel and tyreassembly on which a vehicle rollswheel bay

wheel bay /�wi�l be/ noun a space inthe fuselage or wing structure in whichthe wheel is housed after retraction � Toavoid damage to the wheel bay, the nose


251 width

wheel must be aligned in a fore and aftdirection during retraction.wheel bearingwheel bearing /�wi�l �beərŋ/ nouna device which allows the wheel torotate freely around the axlewheel fairingwheel fairing /�wi�l �feərŋ/ nounsame as spatwheels upwheels up /�wi�lz ��p/ adjective air-borne after having taken off from a run-waywhereaswhereas /weər |��z/ conjunction butin contrast, on the other hand � In thepiston engine, the cycle is intermittent,whereas in the gas turbine, each proc-ess is continuous. � Kerosene has a lowvapour pressure and boils only at veryhigh altitudes or high temperatures,whereas a wide-cut fuel will boil at amuch lower altitude.wherebywhereby /weə|�ba/ adverb accordingto which � Compression heating relieson the principle whereby the air tem-perature is increased by compression. �In ram air supply systems, the coolingmethod is of the simplest type, wherebythe cold air can be directly admitted tothe cabin via adjustable louvres.whereuponwhereupon /�weərə|�pɒn/ adverb atthat point, or after which � Pitchchanges are achieved using the throttlelever, which is usually taken up andback through a gate in the quadrantwhereupon fuel is added to increasepower.whereverwherever /weər|�evə/ adverb � wher-ever possible in places where it is pos-sible � wherever possible, thunder-storms should be avoided by a widemargin thunderstorms should beavoided by a wide margin in situationsor places where it is possible to avoidthemwhilewhile /wal/ conjunction 1. during thetime that � The pilot is trained to scanan instrument panel, while at the sametime listening to the aircraft radio andflying the aircraft. 2. in spite of the factthat � While metal fatigue is not a mod-ern phenomenon, it is only in recentyears that much emphasis has beenplaced upon determining its causes.(NOTE: Whilst is sometimes used inplace of while.)

whipstall

whipstall /�wpstɔ�l/ noun a manoeu-vre in a small aircraft in which it goesinto a vertical climb, pauses briefly, andthen drops towards the earth, front firstwhole

whole /həυl/ adjective complete � Thewhole aircraft should be inspected toensure that it is free from deposits of ice,snow and frost. � whole number anundivided number, a number which isnot a fractionwide

wide /wad/ adjective 1. referring tothe distance of something measuredfrom side to side � The localiserantenna array is normally about 80 feetwide and 12 feet high. 2. � a wide rangeof temperatures a large differencebetween the lowest and the highest tem-perature � a wide variety of informa-tion a lot of different information. �

widthWide Area Augmentation System

Wide Area Augmentation Sys-tem noun full form of WAASwide-bodied

wide-bodied /�wad �bɒdi�d/ adjec-tive US same as wide-bodywidebody

widebody /�wadbɒdi/ noun a jet air-craft with a body wide enough toaccommodate three rows of seats acrossthe width of the plane, with spaces oneach side of the middle setwide-body

wide-body /�wad �bɒdi/ adjectivereferring to a jet aircraft with a bodywide enough to have three sets of pas-senger seats in a row across the width ofthe plane, with spaces on each side ofthe middle setwide-cut fuel

wide-cut fuel /�wad k�t �fju�əl/noun a general term for aviation turbinefuels made up of a wider variety ofpetroleum products than kerosene-typefuels � Kerosene has a low vapour pres-sure and boils only at very high alti-tudes or high temperatures, whereas awide-cut fuel will boil at a much loweraltitude.widespread

widespread /�wadspred/ adjectivefound or distributed across a large area� The storm caused widespread dam-age. � widespread precipitation rain-fall or snowfall covering a large areawidth

width /wdθ/ noun the distance ofsomething measured from side to side,compared to length � The polar front jet


wind 252

stream may have a width of up to 200nm (nautical miles). � widewindwind1 /wnd/ noun horizontal move-ment of air in relation to the Earth’s sur-facewindwind2 /wand/ verb to move in a curv-ing or twisting manner � If a wire iswound as a coil, the field will be likethat of a bar magnet. (NOTE: winding –wound)windblastwindblast /�wndblɑ�st/ noun theharmful effect of air flow on a pilot whohas ejected from an aircraft travelling athigh speedwind conewind cone /�wnd kəυn/ noun sameas windsockwind currentswind currents /�wnd �k�rənts/ plu-ral noun the movement of air in a partic-ular direction through a mass of airwhich is not moving so muchwind directionwind direction /�wnd da |�rekʃən/noun a description of where the wind isblowing from, given as north, south,east, west, etc., or a number of degrees,e.g. a wind coming from the west wouldbe a wind direction of 270° � Winddirection and speed only affect themovement of the aircraft over theground.wind gradientwind gradient /�wnd �$rediənt/noun the rate of increase of windstrength with unit increase in heightabove ground level � After take-off, asthe aircraft gains altitude, the groundspeed may be affected by the wind gra-dient.windingwinding /�wandŋ/ noun a series of360° turns of wire � The voltage in eachwinding is directly proportional to thenumber of turns in each winding.windmillwindmill /�wndml/ verb to turnround by wind force only withoutengine powerwindscreenwindscreen /�wndskri�n/ noun thefront window of an aircraft throughwhich the pilot has forward vision � Thewindscreen is a glass laminated con-struction with an electrical element,made of gold film, sandwiched betweenthe layers. � wiperwindshearwindshear /�wndʃə/ noun a changein wind direction and speed betweenslightly different altitudes � Windshear,

if strong enough, can produce clear airturbulence. � Fly-by-wire technologycan be very useful in windshear situa-tions.windshieldwindshield /�wndʃi�ld/ noun USsame as windscreenwindsockwindsock /�wndsɒk/ noun a pole atthe top of which is a fabric tube throughwhich the wind blows, showing thewind directionwindspeedwindspeed /�wndspi�d/ noun thespeed of the wind which, if combinedwith a direction, is called velocity. It isusually measured in knots. � Winddirection is given in degrees truerounded to the nearest 10°, followed bythe mean windspeed.wind tunnelwind tunnel /�wnd �t�n(ə)l/ noun atunnel-shaped chamber through whichair can be passed at a known speed inorder to test the aerodynamic propertiesof an object such as an aircraft placedinside itwind velocitywind velocity /�wnd və|�lɒsti/noun wind speed and directionwindwardwindward /�wndwəd/ adjective,adverb facing the direction from whichthe wind blows. Opposite lee � wind-ward of a range of hills upwind of therange of hills � If precipitation occurs,water will have been removed from theatmosphere thus causing the air on thelee side to be drier than that on thewindward side.wingwing /wŋ/ noun the main horizontalaerofoil or mainplane � The wing sup-ports the weight of the aircraft in flight.wingletwinglet /�wŋlət/ noun an upturnedwing tip or small additional vertical aer-ofoil on a wing tip � The attachment ofwinglets improved the handling charac-teristics of the aeroplane.wing loadingwing loading /�wŋ �ləυdŋ/ nounthe weight of an aircraft per unit wingareawingmanwingman /�wŋm�n/ noun a pilotwho flies in a position behind and to theside of the leader of a group of flyingaircraftwingoverwingover /�wndəυvə/ noun amanoeuvre to turn a flying aircraft inwhich the pilot puts the aircraft into a


253 WP

steep turning climb until it almost stallsand then allows the nose to fallwing panelwing panel /�wŋ �p�n(ə)l/ noun arectangular aluminium section of theaircraft skin of a wing � Wing panels oflight aircraft are normally rivetedtogether.wing rootwing root /�wŋ ru�t/ noun the part ofthe wing where it meets with the fuse-lagewingspanwingspan /�wŋsp�n/ noun a meas-urement from the tip of one wing to thetip of the other wing � The wingspan ofthe aircraft is 7 metres.wing tipwing tip /�wŋ tp/ noun the outer-most part of the wing � As an aircrafttakes off, the forces on the wing tip andwing surfaces start reversing directionand instead of being only downwardforces of weight, they become upwardforces of lift.wipewipe /wap/ verb to clean or to dry byusing a cloth � In the event of hydraulicfluid spillage on paintwork, the affectedarea should be wiped clean immedi-ately.wiperwiper /�wapə/ noun a device with arubber blade which clears rain, snow,etc., from a windscreen � In some cir-cumstances, such as heavy rainstorms,the windscreen wipers may not be ableto cope and pilot’s visibility is impaired.wirewire /�waə/ noun metal drawn out intothe form of a thread or string � Whilethe shunt coil is made of fine wire whichgives a high resistance and small cur-rent flow, the series coil is made of thickwire, which gives a low resistance andlarge current flow.wire meshwire mesh /�waə meʃ/ noun metalsheeting made of criss-crossed wiringwithdrawwithdraw /wð |�drɔ�/ verb to pullback, to draw back � Instructions aregiven to the cabin crew to arm theescape devices immediately the board-ing steps or airbridges are withdrawn.(NOTE: withdrew – withdrawn)

withinwithin /w|�ðn/ preposition in orinside � Great care must be taken toensure that the aircraft operates withinregulated or permissible weight limits.� within two hours in about two hoursor less, but not morewithstandwithstand /wð|�st�nd/ verb to resistor bear � Wings must be capable of notonly withstanding the aircraft weight,but also the stresses and strains whichare imposed during flight.WMOWMO abbreviation World Meteorolog-ical Organizationworkwork /w%�k/ noun 1. the operation of aforce to produce movement or someother physical change � 1 horsepower isdefined as 33,000 foot-pounds of workaccomplished in one minute (a foot-pound being the ability to lift a onepound weight a distance of one foot). 2.something which has to be done, e.g.maintenance � Work is being carriedout on the auxiliary power unit (APU).3. something done to earn a living � Sheenjoys her work as an airport securityofficer. � verb 1. to operate, to function� the computer doesn’t work the com-puter doesn’t operate as it should dobecause there is something wrong withit 2. to do something such as mainte-nance � Engineers worked on the air-craft all night. 3. to do something toearn a living � She works for a large air-line. 4. � to work out to calculate, tosolve a mathematical problem � Air-craft performance is a function ofweight and therefore it is important thatyou can work out weight from volumeand vice-versa.working conditionsworking conditions /�w%�kŋ kən|

�dʃ(ə)nz/ plural noun those aspects ofworking lives which affect the way peo-ple feel about their workwork loadwork load /�w%�k ləυd/ noun theshare of work done by a person, systemor deviceWPWP abbreviation waypoint


XYZX-rayX-ray /�eks re/ noun 1. a ray with avery short wavelength, which is invisi-ble, but can go through soft tissue ormaterial and register as a photograph ona film 2. a photograph taken using X-rays � verb to take an X-ray photographof luggageyardyard /jɑ�d/ noun a unit of length in theUS and British Imperial Systems equalto 3 ft or 0.9144 m. Abbreviation ydyawyaw /jɔ�/ noun rotation of the aircraftaround its vertical axis � Three-axiscontrol of roll, pitch and yaw is effectedby ailerons, elevators and rudder. �

verb to rotate around the vertical axis �

Single-engine, propeller-driven aircrafttend to yaw on take-off.yokeyoke /jəυk/ noun 1. a type of aircraftcontrol column by which the pilot con-trols ailerons by rotating a device on topof the column to the left or right �

Rotate the yoke to the left to roll the air-craft to the left. 2. a supporting structurelike the forked metal mounting for thenosewheel � The yoke was damaged inthe incident.ZZ abbreviation Zulu timezerozero /�zərəυ/ noun nought or the fig-ure 0 � If the atmospheric pressure at an

airfield is 1,000 millibars (mb) and thispressure is set on the sub-scale of anaircraft altimeter, then when that air-craft touches down at the airfield, thealtimeter will read zero.zero-zerozero-zero /�zərəυ �zərəυ/ adjectivereferring to flying conditions of thick,low cloud when a pilot can see nothingahead and nothing above or below theaircraftzonalzonal /�zəυn(ə)l/ adjective referring toone of the five parts into which theEarth’s surface is divided by imaginarylines parallel to the equator � The circu-lation of air around the Earth is zonal incharacter.zonezone /zəυn/ noun 1. an area with par-ticular features or purpose 2. an admin-istrative area of airspace � control zone� aerodrome traffic zone (ATZ) 3. one offive divisions into which the Earth’ssurface is divided by imaginary linesparallel to the equator � temperate zone� climatic zonezoomzoom /zu�m/ verb to make an aircraftclimb rapidly at a very steep angle, ormove upwards in this wayZulu timeZulu time /�zu�lu� tam/ noun �

Greenwich Mean Time


SUPPLEMENTS

The Phonetic AlphabetStandard words and phrases used in pilot communicationsAircraft registration codesAirline codesAirport codesLocal times around the worldInternational dialling codesStandard symbols and abbreviationsWeights and measuresConversion factors

The Phonetic AlphabetCertain letters of the alphabet sound very similar, especially when a person istalking on the telephone or radio. The phonetic alphabet is designed to preventconfusion, by using a distinctive word to represent each letter.

Aa Alpha* ��lfəBb Bravo �brɑvəυCc Charlie �tʃɑliDd Delta �deltəEe Echo �ekəυFf Foxtrot �fɒkstrɒtGg Golf �ɒlfHh Hotel həυ�telIi India �ndiəJj Juliet �d�uli�etKk Kilo �kiləυLl Lima �liməMm Mike makNn November nə�vembəOo Oscar �ɒskəPp Papa �p�pəQq Quebec kw�bekRr Romeo �rəυmiəυSs Sierra si�erəTt Tango �t�n�əυUu Uniform �junfɔmVv Victor �vktəWw Whisky** �wskiXx X-Ray �eksreYy Yankee �j�ŋkiZz Zulu �zulu

* Alfa in US English** Whiskey in US English

Standard words and phrases

Word/Phrase MeaningAcknowledge Let me know that you have received and understood this

message.Affirm YesApproved I give you permission for what you asked.Cancel Cancel the last clearance I gave to you.Check Examine a system or procedure.Cleared I give permission for you to continue, bearing in mind

the conditions already given.Confirm Have I correctly received the following … ? or Did you

correctly receive this message ?Contact Contact by radio …Correct That is correct.Correction An error was made in the last transmission. What

follows is correct.Disregard Assume that the last transmission was not sent.How do you read? Tell me how good this transmission is on a 1 to 5 scale

where 1 = unreadable (cannot understand) to5 = excellent reception (no difficulty in understanding).

I say again I am repeating in order to make my meaning very clear.Over My transmission is finished and I want a response from

you.Out This exchange of transmissions is finished. I do not want

a response from you.Pass your message Proceed with your message.Read back Repeat all, or the specified part of this message back to

me exactly as received.Request I want to know or I want to have.Roger I have received all of your last transmission.Say again Repeat all, or the following part of your last

transmission.Speak slower Speak more slowly.Standby Wait and I will call you.Verify Check and confirm with me.Wilco I understand your message and will comply with it.Words Twice (as a request) Communication is difficult. Please send

every word or group of words twice.(as information) Because communication is difficult,every word or group of words in this message will besent twice.

Aircraft registration codesThese codes are painted on all aircraft, showing their country of registration.3A Monaco3B Mauritius3C Equatorial Guinea3D Swaziland3X Guinea4K Azerbaijan4R Sri Lanka4U United Nations Organisation4X Israel5A Libya5B Cyprus5H Tanzania5N Nigeria5R Madagascar5T Mauritania5U Niger5V Togo5W Samoa5X Uganda5Y Kenya6O Somalia6V Senegal6Y Jamaica7O Yemen7P Lesotho7Q Malawi7T Algeria8P Barbados8Q Maldives8R Guyana9A Croatia9G Ghana9H Malta9J Zambia9K Kuwait9L Sierra Leone9M Malaysia9N Nepal9Q Democratic Republic of the

Congo9U Burundi9V Singapore9XR Rwanda9Y Trinidad and TobagoA2 Botswana

A3 TongaA40 OmanA5 BhutanA6 United Arab EmiratesA7 QatarA9C BahrainAP PakistanB China & TaiwanB-H Hong KongB-M MacauC CanadaC2 NauruC3 AndorraC5 GambiaC6 BahamasC9 MozambiqueCC ChileCN MoroccoCP BoliviaCS PortugalCU CubaCX UruguayD GermanyD2 AngolaD4 Cape VerdeD6 Comoros IslandsDQ FijiEC SpainEI IrelandEK ArmeniaEP IranER MoldovaES EstoniaET EthiopiaEW BelarusEY TajikistanEZ TurkmenistanF FranceF New Caledonia

(France)F Guadeloupe (France)F Martinique (France)F Tahiti (French

Polynesia)G United Kingdom

Aircraft registration codes continuedH4 Solomon IslandsHA HungaryHB Switzerland &

LiechtensteinHC EcuadorHH HaitiHI Dominican RepublicHK ColombiaHL South KoreaHP PanamaHR HondurasHS ThailandHV The VaticanHZ Saudi ArabiaI ItalyJ2 DjiboutiJ3 GrenadaJ5 Guinea BissauJ6 St LuciaJ7 DominicaJ8 St Vincent and the

GrenadinesJA JapanJU MongoliaJY JordanLN NorwayLV ArgentinaLX LuxembourgLY LithuaniaLZ BulgariaN USAOB PeruOD LebanonOE AustriaOH FinlandOK Czech RepublicOO BelgiumOY DenmarkP North KoreaP2 Papua New GuineaP4 ArubaPH NetherlandsPJ Netherland AntillesPK IndonesiaPP BrazilPZ Suriname

RA Russian FederationRP PhilippinesS2 BangladeshS5 SloveniaS7 SeychellesS9 Sao Tome and PrincipeSE SwedenSP PolandST SudanSU EgyptSX GreeceT2 TuvaluT3 KiribatiT7 San MarinoT8A PalauT9 Bosnia-HerzegovinaTC TurkeyTF IcelandTG GuatemalaTI Costa RicaTJ CameroonTL Central African

RepublicTN Congo-BrazzavilleTR GabonTS TunisiaTT ChadTU Côte d’IvoireTY BeninTZ MaliUK UzbekistanUR UkraineV2 Antigua and BarbudaV3 BelizeV4 St Kitts and NevisV5 NamibiaV6 MicronesiaV7 Marshall IslandsV8 BruneiVH AustraliaVN VietnamVP, VQ British Overseas

TerritoriesVP-A Anguilla (UK)VP-B Bermuda (UK)VP-C Cayman Islands (UK)

Aircraft registration codes continuedVP-F Falkland IslandsVP-G Gibraltar (UK)VP-L British Virgin IslandsVP-M MontserratVQ-H St Helena (UK)VQ-T Turks and Caicos

Islands (UK)VR-B BermudaVR-C Cayman IslandVR-G GibraltarVR-H Hong KongVT IndiaXA MexicoXT Burkina FasoXU CambodiaXY Myanmar

YA AfghanistanYI IraqYJ VanuatuYK SyriaYL LatviaYN NicaraguaYR RomaniaYS El SalvadorYU Serbia and MontenegroYV VenezuelaZ ZimbabweZA AlbaniaZK New ZealandZP ParaguayZS South Africa

Airline codes2J Air Burkina4U GermanWings9U Air MoldovaAA American AirlinesAB Air BerlinAC Air CanadaAF Air FranceAH Air AlgerieAI Air IndiaAM AeromexicoAQ Aloha AirlinesAR Aerolineas ArgentinasAS Alaska AirlinesAT Royal Air MarocAY FinnairAZ AlitaliaBA British AirwaysBB Seaborne AirlinesBD bmi British MidlandBG Biman Bangladesh AirlinesBH Transtate AirlinesBI Royal Brunei AirlinesBL Pacific AirlinesBM Air SiciliaBO Bouraq Indonesia AirlinesBP Air BotswanaBR EVA AirBU Braathens ASABW BWIA - West Indies

AirwaysCA Air China InternationalCB ScotAirwaysCI China AirlinesCJ China Northern AirlinesCM COPA (Compania

Panamena de Aviación)CO Continental AirlinesCU CubanaCX Cathay Pacific AirwaysCY Cyprus AirwaysCZ China Southern AirlinesDL Delta Air LinesDS Easyjet SwitzerlandDT TAAG Angola AirlinesDU Hemus AirDY Air DjiboutiEI Aer LingusEK EmiratesET Ethiopian AirlinesFC Finncomm

FG Ariana Afghan AirlinesFI IcelandAirFJ Air PacificFO Airlines of TasmaniaFR RyanairGA Garuda IndonesiaGC Gambia International

AirlinesGF Gulf AirGH Ghana AirwaysGL Air GreenlandGN Air GabonGR Aurigny Air ServicesGY Guyana AirwaysHA Hawaiian AirlinesHM Air SeychellesHP America West AirlinesHV Transavia AirlinesHY Uzbekistan AirwaysIB IberiaIC Indian AirlinesIE Solomon AirlinesIR Iran AirIV Wind JetIY Yemenia - Yemen AirwaysJL Japan AirlinesJM Air JamaicaJP Adria AirwaysJU JAT AirwaysJY Interisland AirwaysKE Korean Air LinesKL KLM Royal Dutch AirlinesKM Air MaltaKP Kiwi International AirlinesKQ Kenya AirwaysKU Kuwait AirwaysKV KavminvodyaviaKX Cayman AirwaysKY Linhas Aereas de Air Sao

Tome and PrincipeLA Lan-ChileLG LuxairLH LufthansaLN Jamahiriya Libyan Arab

AirlinesLO LOT Polish AirlinesLY El Al Israel AirlinesLX SwissLZ Balkan-Bulgarian Airlines

Airline codes continuedMA MALEV Hungarian

AirlinesMD Air MadagascarMH Malaysia AirlinesMK Air MauritiusMN Commercial AirwaysMR Air MauritanieMS EgyptairNF Air VanuatuNG Lauda AirNH All Nippon AirwaysNO Aus-AirNQ Air JapanNV Nakanihon AirlinesNW Northwest AirlinesNZ Air New ZealandOA Olympic AirlinesOB Astrakhan AirlinesOK Czech AirlinesOM MIAT - Mongolian

AirlinesON Air NauruOO SkyWest AirlinesOS Austrian AirlinesOU Croatia AirlinesOV Estonian AirPB Provincial AirlinesPC Air FijiPH PolynesianPK Pakistan International

AirlinesPR Philippine AirlinesPS Ukraine International

AirlinesPU Pluna Lineas Aereas

UruguayasPX Air NiuginiPY Surinam AirwaysPZ TAM - Transportes Aereos

del MercosurQF Qantas AirwaysQM Air MalawiQR Qatar AirwaysQU East African AirlinesQV Lao AirlinesQX Horizon AirRA Royal Nepal AirlinesRB Syrian Arab AirlinesRG VarigRJ Royal Jordanian

RK Royal Khymer AirlinesRO TAROMSA South African AirwaysSD Sudan AirwaysSK SASSN SN Brussels AirlinesSQ Singapore AirlinesSU Aeroflot Russian AirlinesSV Saudi Arabian AirlinesSW Air NamibiaTC Air TanzaniaTE Lithuanian AirlinesTG Thai Airways InternationalTK Turkish AirlinesTM LAM - Lineas Aereas de

MoçambiqueTN Air Tahiti NuiTP TAP - Air PortugalTU TunisairU2 EasyjetUA United AirlinesUB Myanmar AirwaysUI Eurocypria AirlinesUL SriLankan AirlinesUM Air ZimbabweUS US AirwaysUY Cameroon AirlinesVE AVENSAVH AeropostalVJ Jatayu AirlinesVN Vietnam AirlinesVO Tyrolean AirlinesVR TACV - Transportes

Aereos de Cabo VerdeVS Virgin AtlanticVU Air IvoireVX V BirdW6 Wizz AirWG Wasaya AirlinesWJ Labrador AirwaysW6 Wizz AirWG Wasaya AirlinesWJ Labrador AirwaysWN Southwest AirlinesWR Royal Tongan AirlinesWY Oman AviationYK Kibris Turk Hava YollariYN Air CreebecYU DominairZB Monarch Airlines

Airport codescode airport countryABJ Abidjan Côte d’IvoireABZ Aberdeen UKACA Acapulco MexicoACC Accra GhanaADD Addis Ababa EthiopiaADL Adelaide AustraliaAGP Malaga SpainAKL Auckland New ZealandALC Alicante SpainALG Algiers AlgeriaAMM Amman JordanAMS Amsterdam NetherlandsANC Anchorage USAANK Ankara TurkeyANR Antwerp BelgiumANU Antigua AntiguaARN Stockholm Arlanda SwedenASU Asuncion ParaguayATH Athens GreeceATL Atlanta USAAUH Abu Dhabi UAEAXA Wallblake AnguillaBAH Bahrain BahrainBCN Barcelona SpainBDA Bermuda BermudaBER Berlin GermanyBEY Beirut LebanonBFS Belfast UKBGI Bridgetown BarbadosBGO Bergen NorwayBHX Birmingham UKBIO Bilbao SpainBJL Banjul GambiaBJM Bujumbura BurundiBJS Beijing ChinaBKK Bangkok ThailandBLQ Bologna ItalyBNE Brisbane AustraliaBOD Bordeaux FranceBOG Bogota ColombiaBOM Mumbai IndiaBOS Boston USABRE Bremen GermanyBRN Berne SwitzerlandBRS Bristol UK

Airport codes continuedcode airport countryBRU Brussels BelgiumBSL Basle/Mulhouse SwitzerlandBTS Bratislava SlovakiaBUD Budapest HungaryBUE Buenos Aires ArgentinaBUH Bucharest RomaniaBWI Baltimore USABZV Brazzaville CongoCAI Cairo EgyptCAS Casablanca MoroccoCBR Canberra AustraliaCCS Caracas VenezuelaCCU Calcutta IndiaCDG Paris Charles de Gaulle FranceCGK Jakarta IndonesiaCGN Cologne GermanyCHC Christchurch New ZealandCHI Chicago USACLE Cleveland USACMB Colombo Sri LankaCMN Casablanca Mohamed V MoroccoCNS Cairns AustraliaCOO Cotonou BeninCPH Copenhagen DenmarkCPT Cape Town South AfricaCUR Curacao Neth. AntillesCVG Cincinnati USACWL Cardiff UKDAC Dhaka BangladeshDAM Damascus SyriaDBV Dubrovnik CroatiaDCA Washington National USADCF Dominica DominicaDEL Delhi IndiaDEN Denver USADFW Dallas/Fort Worth USADKR Dakar SenegalDOM Dominica OmanDRW Darwin AustraliaDTT Detroit USADUB Dublin IrelandDUR Durban South AfricaDUS Dusseldorf GermanyDXB Dubai UAEEBB Entebbe Uganda

Airport codes continuedcode airport countryEDI Edinburgh UKEMA East Midlands UKEWR Newark USAFAO Faro PortugalFCO Rome Fiumicino ItalyFIH Kinshasa CongoFRA Frankfurt GermanyFUK Fukuoka JapanGBE Gabarone BotswanaGCI Guernsey UKGCM Grand Cayman Cayman IslandsGEO Georgetown GuyanaGIB Gibraltar GibraltarGIG Rio de Janeiro BrazilGLA Glasgow UKGND Grenada GrenadaGOA Genoa ItalyGOT Gothenburg SwedenGRU Sao Paulo BrazilGRZ Graz AustriaGUA Guatemala City GuatemalaGVA Geneva SwitzerlandHAJ Hanover GermanyHAM Hamburg GermanyHAV Havana CubaHEL Helsinki FinlandHKG Hong Kong Hong KongHNL Honolulu USAHOU Houston USAHRE Harare ZimbabweIAD Washington Dulles USAIAH Houston Intl. USAINN Innsbruck AustriaISB Islamabad PakistanIST Istanbul TurkeyJED Jeddah Saudi ArabiaJER Jersey UKJFK New York Kennedy Intl. USAJKT Jakarta IndonesiaJNB Johannesburg South AfricaKEF Reykjavik IcelandKHI Karachi PakistanKIN Kingston JamaicaKLU Klagenfurt AustriaKOJ Kagoshima Japan

Airport codes continuedcode airport countryKRT Khartoum SudanKUL Kuala Lumpur MalaysiaKWI Kuwait KuwaitLAD Luanda AngolaLAS Las Vegas USALAX Los Angeles USALBA Leeds/Bradford UKLCA Larnaca CyprusLCY London City UKLED St Petersburg RussiaLEJ Leipzig GermanyLGA New York La Guardia USALGW London Gatwick UKLHR London Heathrow UKLIL Lille FranceLIM Lima PeruLIN Milan ItalyLIS Lisbon PortugalLJU Ljubljana SloveniaLLW Lilongwe MalawiLNZ Linz AustriaLOS Lagos NigeriaLPA Gran Canaria SpainLPB La Paz BoliviaLPL Liverpool UKLTN London Luton UKLUN Lusaka ZambiaLUX Luxembourg LuxembourgLYS Lyons FranceMAA Chennai IndiaMAD Madrid SpainMAN Manchester UKMBA Mombasa KenyaMCI Kansas City Intl. USAMCO Orlando USAMCT Muscat OmanMEL Melbourne AustraliaMEX Mexico City MexicoMIA Miami USAMIL Milan ItalyMKC Kansas City USAMLA Malta MaltaMLW Monrovia LiberiaMME Teeside UKMNL Manila Philippines

Airport codes continuedcode airport countryMOW Moscow RussiaMPM Maputo MozambiqueMQS Mustique GrenadinesMRS Marseilles FranceMRU Mauritius MauritiusMSP Minneapolis St Paul USAMSY New Orleans USAMUC Munich GermanyMVD Montevideo UruguayMXP Milan ItalyNAP Naples ItalyNAS Nassau BahamasNBO Nairobi KenyaNCE Nice FranceNCL Newcastle UKNGO Nagoya JapanNOU Nourrea New CaledoniaNRT Tokyo Narita JapanNUE Nuremburg GermanyNYC New York USAORD Chicago O’Hare USAORK Cork IrelandORL Orlando USAORY Paris Orly FranceOSA Osaka JapanOSL Oslo NorwayOTP Bucharest Otopeni RomaniaPAR Paris FrancePBM Paramaribo SurinamPDX Portland USAPEK Beijing ChinaPER Perth AustraliaPHL Philadelphia USAPHX Phoenix USAPIT Pittsburgh USAPLH Plymouth UKPMI Palma de Mallorca SpainPOM Port Moresby Papua New GuineaPOS Port of Spain Trinidad and TobagoPPT Papeete French PolynesiaPRG Prague Czech RepublicPSA Florence Pisa ItalyPTY Panama City PanamaRAR Rarotonga Cook IslandsREK Reykjavik Iceland

Airport codes continuedcode airport countryRIO Rio de Janeiro BrazilRIX Riga LatviaROM Rome ItalyRTM Rotterdam NetherlandsRUH Riyadh Saudi ArabiaSAH Sana’a YemenSAN San Diego USASAO Sao Paulo BrazilSCL Santiago ChileSEA Seattle USASEL Seoul South KoreaSFO San Francisco USASHA Shanghai ChinaSHJ Sharjah UAESIN Singapore SingaporeSKG Thessaloniki GreeceSLC Salt Lake City USASLU Saint Lucia Saint LuciaSNN Shannon IrelandSOF Sofia BulgariaSOU Southampton UKSTL Saint Louis USASTN London Stansted UKSTO Stockholm SwedenSTR Stuttgart GermanySVG Stavanger NorwaySVO Moscow Sheremetyevo RussiaSVQ Seville SpainSXB Strasbourg FranceSXF Berlin Schoenefeld GermanySYD Sydney AustraliaSZG Salzburg AustriaTCI Tenerife SpainTGU Tegucigalpa HondurasTHF Berlin Tempelhof GermanyTHR Tehran IranTLL Tallinn EstoniaTLS Toulouse FranceTLV Tel Aviv IsraelTPA Tampa USATPE Taipei TaiwanTRN Turin ItalyTUN Tunis TunisiaTYO Tokyo JapanUIO Quito Ecuador

Airport codes continuedcode airport countryVCE Venice ItalyVIE Vienna AustriaVLC Valencia SpainVNO Vilnius LithuaniaWAS Washington DC USAWAW Warsaw PolandWDH Windhoek NamibiaWLG Wellington New ZealandYEA Edmonton CanadaYEG Edmonton Intl. CanadaYMQ Montreal Mirabel CanadaYOW Ottawa CanadaYTO Toronto CanadaYUL Montreal Pierre Elliot Canada

Trudeau Intl.YVR Vancouver CanadaYWG Winnipeg CanadaYYC Calgary CanadaYYZ Toronto Lester Pearson CanadaZAG Zagreb CroatiaZRH Zurich Switzerland

Local times around the worldLondon time 1200Abu Dhabi 1600Adelaide 2130Algiers 1300Amsterdam 1300Ankara 1400Astana 1800Athens 1400Baghdad 1500Bangkok 1900Beijing 2000Beirut 1400Berlin 1300Bern(e) 1300Bogota 0700Brasilia 0900Brazzaville 1300Brussels 1300Bucharest 1400Budapest 1300Buenos Aires 0900Cairo 1400Calcutta (Kolkata) 1730Canberra 2200Cape Town 1400Caracas 0800Chicago 0600Colombo 1730Copenhagen 1300Costa Rica 0600Damascus 1400Delhi 1730Dhaka 1800Dublin 1200Gibraltar 1300Hanoi 1900Harare 1400Helsinki 1400Hong Kong 2000Honolulu 0200Istanbul 1400Jakarta 1900Jerusalem 1400Kabul 1630Karachi 1700Khartoum 1400Kiev 1400Kinshasa 1400Kuala Lumpur 2000Kuwait 1500Lagos 1300La Paz 0800Lima 0700Lisbon 1200

London time 1200Luanda 1300Luxembourg 1300Madagascar 1500Madrid 1300Malé 1700Malta 1300Manila 2000Mexico 0600Minsk 1400Montevideo 0900Montreal 0700Moscow 1500Mumbai 1730Nairobi 1500Nassau 0700New York 0700Oslo 1300Ottawa 0700Panama 0700Paris 1300Perth 2000Phnom Penh 1900Prague 1300Pretoria 1400Pyongyang 2100Quebec 0700Rangoon 1830Reykjavik 1200Rio de Janeiro 0900Riyadh 1500Rome 1300San Francisco 0400Santiago 0800Seoul 2100Seychelles 1600Singapore 2000Stockholm 1300Sydney 2200Taipei 2000Tallinn 1400Tbilisi 1600Tehran 1530Tirana 1300Tokyo 2100Toronto 0700Tripoli 1300Tunis 1300Ulan Bator 2000Vienna 1300Warsaw 1300Washington DC 0700Wellington 0000 (+1 day)Yaoundé 1300

International dialling codesAfghanistan 93Albania 355Algeria 213Andorra 376Angola 244Anguilla 264Antigua and Barbuda 268Argentina 54Armenia 374Australia 61Austria 43Bahamas 242Bahrain 973Bangladesh 880Barbados 246Belarus 375Belgium 32Belize 501Benin 229Bermuda 441Bhutan 975Bolivia 591Bosnia 387Botswana 267Brazil 55Brunei 673Bulgaria 359Burkina Faso 226Burma (see Myanmar)Burundi 257Cambodia 855Cameroon 237Canada 1Cape Verde Islands 238Cayman Islands 345Central African Republic 236Chad 235Chile 56China 86Colombia 57Comoros 269Congo (Republic of the) 242Congo 243(Democratic Republic of the)

Costa Rica 506Croatia 385Cuba 53Cyprus 357Czech Republic 420Denmark 45Djibouti 253Dominica 767Dominican Republic 809Ecuador 593

Egypt 20El Salvador 503Equatorial Guinea 240Estonia 372Ethiopia 251Falkland Islands 500Fiji 679Finland 358France 33French Guiana 594Gabon 241Gambia 220Georgia 679Germany 49Ghana 233Gibraltar 350Great Britain 44Greece 30Grenada 473Guatemala 502Guinea 224Guinea-Bissau 245Guyana 592Haiti 509Honduras 504Hong Kong 852Hungary 36Iceland 354India 91Indonesia 62Iran 98Iraq 964Irish Republic 353Israel 972Italy 39Ivory Coast 225Jamaica 876Japan 81Jordan 962Kazakhstan 7Kenya 254Kuwait 965Kyrgyzstan 996Laos 856Latvia 371Lebanon 961Lesotho 266Liberia 231Libya 218Liechtenstein 423Lithuania 370Luxembourg 352Macao 853

International dialling codes continuedMacedonia 389(Former Yugoslav Republic of)

Madagascar 261Madeira 351Malawi 265Malaysia 60Maldives 960Mali 223Malta 356Mauritania 222Mauritius 230Mexico 52Moldova 373Monaco 377Mongolia 976Montserrat 664Morocco 212Mozambique 258Myanmar 95Namibia 264Nauru 674Nepal 977Netherlands 31New Zealand 64Nicaragua 505Niger 227Nigeria 234North Korea 850Norway 47Oman 968Pakistan 92Panama 507Papua New Guinea 675Paraguay 595Peru 51Philippines 63Poland 48Portugal 351Puerto Rico 787Qatar 974Réunion 262Romania 40Russia 7Rwanda 250St Lucia 758

St Vincent 784Samoa 378Saudi Arabia 966Senegal 221Serbia and Montenegro 381Seychelles 248Sierra Leone 232Singapore 65Slovakia 42Slovenia 386Somalia 252South Africa 27South Korea 82Spain 34Sri Lanka 94Sudan 249Suriname 597Swaziland 268Sweden 46Switzerland 41Syria 963Taiwan 886Tanzania 255Thailand 66Togo 228Tonga 676Trinidad & Tobago 868Tunisia 216Turkey 90Turkmenistan 993Tuvalu 688Uganda 256Ukraine 380United Arab Emirates 971United Kingdom 44USA 1Uruguay 598Uzbekistan 998Vanuatu 678Venezuela 58Vietnam 84Yemen 967Zambia 260Zimbabwe 263

Standard symbols and abbreviations+ positive- negative� ohmº degree� inch(es)� foot (feet)amp ampereBtu British thermal unitC Celsiuscal calorie(s)cal large calorie(s)cm centimetrecos cosinecu. cm, cc cubic centimetre(s)cu. in cubic inch(es)cu. ft cubic foot (feet)cu. m cubic metre(s)dB decibeldeg degreeESHP equivalent shaft

horsepowerF faradF Fahrenheitft foot (feet)ft-lb(s) foot-pound(s)g gramgal gallonHP horsepowerhr hourHz hertzin inch(es)in hg inch(es) of mercuryIPS inches per secondk kiloK kelvinkg kilogramkHz kilohertzkm kilometrekW kilowattkW-hr kilowatt hourl litrelb pound

m metremb millibarmf, �f microfaradmHz millihertzMHz megahertzmi mile(s)mm millimetreMPH miles per hourmv millivoltneg negativeoz ounce(s)pf, ��f picofaradpos positivePPH pounds per hourPPM parts per millionPSI pounds per square inchPSIA pounds per square inch

absolute pressurePSID pounds per square inch

differential pressurePSIG pounds per square

inch gagept pintqt quartR Rankinerev. revolution(s)rpm, r.p.m. revolutions per minutesec. secondSHP shaft horsepowersin sinesq. cm, cm2 square centimetre(s)sq. in square inch(es)sq. ft square foot (feet)sq. m, m2 square metresq. mi square mile(s)sq. mil square miltan tangentTEHP total equivalent

horsepowerTHP total horsepowerV voltyd(s) yard(s)

Weights and Measures: Metric MeasuresLength1 millimetre (mm) = 0.0394 in1 centimetre (cm) = 10 mm = 0.3937 in1 decimetre (dm) = 10 cm = 3.937 in1 metre (m) = 100 cm = 1.0936 yds1 kilometre (km) = 1000 m = 0.6214 mile

Area1 square millimetre (mm2) = 0.0016 sq. in.1 square centimetre (cm2) = l00 mm2 = 0.155 sq. in1 square metre (m2) = l0,000 cm2 = 1.196 sq. yds1 are (a) = 100 m2 = 119.6 sq. yds1 hectare (ha) = 100 ares = 2.4711 acres1 square kilometre (km2) = 100 hectares = 0.3861 sq. mile

Weight1 milligram (mg) = 0.0154 grain1 gram (g) = 1000 mg = 0.0353 oz1 kilogram (kg) = 1000 g = 2.2046 lb1 tonne (t) = 1000 kg = 0.9842 ton

Volume1 cubic centimetre (cm3) = 0.061 cu. in1 cubic decimetre (dm3) = 1000 cm3 = 0.0351 cu. ft1 cubic metre (m3) = 1000 dm3 = 1.308 cu. yds

Liquid Volume1 litre (l) = 1 dm3 = 1.76 pt1 hectolitre (hl) = 100 l = 22 gal

Weights and Measures: Imperial MeasuresLength1 inch (in) = 2.54 cm1 foot (ft) = 12 in = 0.3048 m1 yard (yd) = 3 ft = 0.9144 m1 rod (rd) = 5.5 yds = 4.0292 m1 chain = 4 rds = 20.117 m1 furlong = 10 chains = 201.17 m1 mile = 8 furlongs = 1.6093 km1 nautical mile = 2025.4 yds = 1.852 km

Area1 square inch = 6.4516 cm2

1 square foot = 144 sq. ins = 0.0929 m2

1 square yard = 9 sq. ft = 0.8361 m2

1 acre = 4840 sq. yds = 4046.9 m2

1 square mile = 640 acres = 259 hectares

Weight1 ounce (oz) = 437.6 grains = 28.350 g1 pound (lb) = 16 oz = 0.4536 kg1 stone = 14 lb = 6.3503 kg1 hundredweight (cwt) = 112 lb = 50.802 kg1 long ton = 20 cwt = 1.0161 t

Volume1 cubic inch = 16.387 cm3

1 cubic foot = 1728 cu. ins = 0.0283 m3

1 cubic yard = 27 cu. ft = 0.7646 m3

Liquid Volume1 fluid ounce (fl. oz) = 8 fl. drachms = 28.413 cm3

1 pint (pt) = 20 fl. oz = 568.26 cm3

1 pint = 4 gills = 0.5683 l1 quart (qt) = 2 pt = 1.1365 l1 gallon (gal) = 8 pt = 4.5461 l1 bushel (bu) = 8 gal = 36.369 l

Liquid Volume (US)1 fluid ounce (US) = 29.574 ml1 pint (US) = 16 fl. oz (US) = 0.4723 l1 gallon (US) = 8 pt (US) = 3.7854 l

Conversion factors: Imperial to MetricLength Multiply byinches � millimetres 25.4inches � centimetres 2.54feet � metres 0.3048yards � metres 0.9144statute miles � kilometres 1.6093nautical miles � kilometres 1.852

Area Multiply bysquare inches � square centimetres 6.4516square feet � square metres 0.0929square yards � square metres 0.8361acres � hectares 0.4047square miles � square kilometres 2.5899

Volume Multiply bycubic inches � cubic centimetres 16.3871cubic feet � cubic metres 0.0283cubic yards � cubic metres 0.7646

Liquid Volume Multiply byfluid ounces (UK) � litres 0.0284fluid ounces (US) � litres 0.0296pints (UK) � litres 0.5682pints (US) � litres 0.4732gallons (UK) � litres 4.546gallons (US) � litres 3.7854

Weight Multiply byounces (avoirdupois) � grams 28.3495ounces (troy) � grams 31.1035pounds � kilograms 0.4536tons (long) � tonnes 1.016

Conversion factors: Metric to ImperialLength Multiply bymillimetres � inches 0.0394centimetres � inches 0.3937metres � feet 3.2806metres � yards 1.9036kilometres � statute miles 0.6214kilometres � nautical miles 0.54

Area Multiply bysquare centimetres � square inches 0.155square metres � square feet 10.764square metres � square yards 1.196hectares � acres 2.471square kilometres � square miles 0.386

Volume Multiply bycubic centimetres � cubic inches 0.061cubic metres � cubic feet 35.315cubic metres � cubic yards 1.308

Liquid Volume Multiply bylitres � fluid ounces (UK) 35.1961litres � fluid ounces (US) 33.8150litres � pints (UK) 1.7598litres � pints (US) 2.1134litres � gallons (UK) 0.2199litres � gallons (US) 0.2642

Weight Multiply bygrams � ounces (avoirdupois) 0.0353grams � ounces (troy) 0.0322kilograms � pounds 2.2046tonnes � tons (long) 0.9842

Temperature Operation(in sequence)

Celsius � Fahrenheit x 9, ÷ 5, + 32Fahrenheit � Celsius - 32, x 5, ÷ 9

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