FAST magazine Special A320 - May 2005 - · PDF file05.04.2004 · as airlines strive to further optimize aircraft utilisation and minimize costs, ... chapters the ATA drivers are identi-fied

Dear Customer,

An in-flight interruption is not a regular event. None the less, as airlines strive to further optimize aircraft utilisation and minimizecosts, it is inevitable that the effect of such event will becomemore significant for any given operation.

Herein you will find briefings on the most significant opportunitiescurrently available to minimize in-flight interruptions. The aim is toshare A320 Family fleet experience between all operators.

This FAST Special provides an analysis of in-flight interruptionsrecorded for the A320 Family fleet over the last 4 years. Themain contributors have been identified and consequentlyproposals defined that may allow your airline to further reduce itsin-flight interruption rate.

The proposals range from relatively simple enhancements that are easy to implement to those that are more complex,consequently requiring more time and effort to introduce.However, all are effective means of reducing in-flight interruptionsand in addition offer the possibility to further enhance operationalefficiency.

Information is provided to allow the benefits applicable to your organisation to be easily identified. We now invite you toconsider each proposal in the context of your fleet and itsoperation. Should you need further information to support you,please feel free to contact us.

Antoine VieillardVice President A320 Family ProgrammeCustomer Services

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This issue of FAST has been printed on paperproduced without using chlorine, to reducewaste and help conserve natural resources.Every little helps!

Publisher: Bruno PiquetEditor: Kenneth Johnson

Graphic Designer: Agnès Massol-Lacombe

Customer Services Marketing Tel: +33 (0)5 61 93 43 88

Fax: +33 (0)5 61 93 47 73E-mail: [email protected]

Printer Escourbiac

FAST may be read on Internet http://www.airbus.com/customer/fast/aspunder Customer Services/Publications

ISSN 1293-5476

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Photographs by Hervé Bérenger, Hervé Goussé and Philippe Masclet

Airbus Customer Services

© AIRBUS S.A.S. 2005. All rights reservedNo other intellectual property rights are granted by the delivery of this Magazine than the right

to read it, for the sole purpose of information. This Magazine and its content shall not bemodified and its images shall not be reproduced without prior written consent of Airbus.This Magazine and the material it contains shall not, in whole or in part, be sold, rented,

distributed or licensed to any third party. The information contained in this Magazine may varyover time because of future factors that may affect the accuracy of information herein. Airbusassumes no obligation to update any information contained in this Magazine. When additional

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any damage in connection with the use of this Magazine and of the materials it contains,even if Airbus S.A.S. has been advised of the likelihood of such damages

M A Y 2 0 0 5

Overall analysis

ATA 21 Air conditioningFrançois Gheur

ATA 27 Flight controlsJoan Rendu

ATA 29 Hydraulic systemCédric Turroque

ATA 32 Landing gear systemsJérôme Lesage

ATA 36 Engine bleed air systemPatrick Grave

ATA 52 DoorsArnaud Blanc-Nikolaitchouk

ATA 70-80 Propulsion systemRaquel Sanchez-Garcia

Conclusion

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15

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24

A practical guide to reducing in-flight interruptions

A320 Family

special

ATA 21 - Air conditioning ATA 21 - Air conditioning

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It is essential to minimise the delays and cancellations that accompany theoperation of commercial aircraft. Airbuscontinues to develop and deliver efficient,proven solutions to reduce technicaldelays and cancellations for every aircraftin the A320 Family fleet.

An in-flight interruption such as a turn-back or diversion places the aircraft,it’s passengers, freight and crew in thewrong place and in need of maintenancecrew attention. Furthermore, these eventscan have a major impact throughoutschedules. The trend for A320 Family in-flight interruptions is steadily decliningand today the in-service fleet experiencesan in-flight interruption for technicalreasons about once every 7000 flights.

To ensure that all operators of A320Family aircraft are briefed on theopportunities for minimising in-flightinterruptions within their operation,Airbus Customer Services has producedthis FAST Special. It aims to share fleet-wide experience with all operators.To do this it focuses on the principle rootcauses of in-flight interruptions andconsequently identifies proposals that arewidely applicable and that havedemonstrated their value in terms of notonly minimizing in-flight interruptions but also in reducing delays andcancellations.

0.00

0.02

0.04

0.06

2001 2002 2003 2004

The cost of an in-flight interrup-tion can vary significantly fromone operation to another. Costs aregreatly influenced by the nature ofthe event and the support availableat the aircraft’s location.

The immediate operational impactof an in-flight interruption could be:

• Flying to a runway long enoughto accept the aircraft (in casessuch as flap locks)

• ‘Overweight’ landing• ‘Single engine’ landing

following an in-flight engineshutdown

• Passenger discomfort in thecase of excessive cabin altitude

Further consequences could be:

• Men and materials sent to thediverted aircraft to repair itand/or ferry it back to base

• Cancellation of following flightsfor the aircraft.

• Lack of spares leading to anAOG situation

• Passengers booked onto anotherflight and/or hotel, meal andcompensation costs

• Aircraft, baggage, and freightchecked by the emergencyservices (following smokewarning, for example)

• Other aircraft and crewsrescheduled at short notice

• Flight Crew replacement (due tomaximum flying hoursregulations)

• The aircraft out of service for alengthy period (replacement tobe sourced)

By attributing the in-flight inter-ruption events shown in the chartbelow to their appropriate ATAchapters the ATA drivers are identi-fied. That is, the ATA chaptersagainst which the majority of rootcauses have been attributed. Foreach ATA chapter a specific sec-tion in this FAST Special has beenproduced. Each of these sectionspresents a further breakdown of theevents and based on this, proposalsare made that will allow in-flightinterruptions to be minimized. Itshould be noted that not all propos-als are applicable to all aircraft inthe fleet, but information to allowthe applicability to be determinedhas been provided in all cases.

The issues causing in-flight inter-ruptions can equally result indelays at the departure gate.Therefore, when considering theadded value the proposals made inthis FAST Special will bring to agiven operation, their effectsshould be considered not only inthe context of minimizing in-flightinterruptions but in overall opera-tional efficiency.

A320 FAMILY - IN-FIGHT INTERRUPTION REVIEW - OVERALL ANALYSISA320 FAMILY - IN-FIGHT INTERRUPTION REVIEW - OVERALL ANALYSIS

Most passengers, even frequentflyers, have never experienced anin-flight interruption, such as an InFlight Turn Back (IFTB) or a diver-sion (DV). They are very rare.Nevertheless, airline FleetManagers know that there is a needto consider technical delay reduc-tion and in-flight interruption eventlimitation when looking at aircraftor procedures enhancements.

Global analysis of in-flight inter-ruptions for the A320 Familyshows that there has been a steadi-ly improving trend in the rate overthe last few years.

In-flight interruptions typicallyfollow specific warnings to thepilot indicating:

• Landing gear ‘retracted and uplocked’ not confirmed electrically

• Excessive cabin altitudewarning

• Flight control surface notresponding

• Engine shutdown followingexcessive vibration or exhaustgas temperature

• Hydraulic low level warningdue to leakage

• Smoke warning

A320 world fleetIn-flight interruptions rate per100 revenue takeoffs

0% 5% 10% 15% 20% 25% 30%

ATA 32 LANDING GEAR

ATA 21 AIR CONDITIONING

ATA 70-80 PROP. SYSTEM

ATA 29 HYDRAULICS

ATA 36 PNEUMATICS

ATA 27 FLIGHT CONTROLS

ATA 52 DOORS

Others

14%

14%

14%

9%

8%

6%

6%

29%

In-flight turnbacks for year 2004% contribution pere ATA

The data collectionprocess starts with aPilot Report which

will lead the operator to raisean Air Safety Report (or equivalent) that must besent to its airworthinessauthority. Airbus eithercollects a copy of this ASR,receives the details in theairline’s monthly reliabilityreport, or more frequently,receives the contents of thereliability report plus theincident report text inelectronic format and this isthen loaded directly into theAirbus database in Toulouseusing the followingdefinitions:

• Definition of In-Flight Turn-Back (IFTB): The return of an aircraft to theairport of origin as a result of themalfunction or suspectedmalfunction of any item on theaircraft (Note: also calledAirturnback).

• Definition of Flight Diversion (DV): The landing of an aircraft at anairport other than the airport oforigin or destination as a resultof the malfunction or suspectedmalfunction of any item on theaircraft.

Throughout this documentthe term ‘in-flight interruption’is used when describingeither an IFTB or DV.

Airbus computes:Flight interruption rate per100 revenue takeoffs as(IFTB+DV)* 100/revenue takeoffs.(2001-2004)

Overall analysisOverall analysis

ATA 21Air conditioning


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ATA 21 - AIR CONDITIONING

Proposal 1ATA 21-26-00ENHANCED AEVC

The latest Avionics EquipmentVentilation Computer (AEVC) stan-dard clears two major issues. It cannow deal with disruption of the elec-trical signals from the skin air valves,which previously caused AEVC andskin air valve faults, which couldresult in an in-flight interruption.This new controller also preventsspurious avionics smoke warnings inflight triggered by a pin crack at thelevel of the Random Access Memorymodule. With this latest AEVC stan-dard, shock absorption has also beenimproved and the smoke detector testinhibited in flight.

François GheurEnvironmental Control System

Customer Services Engineering

ATA 21 Distribution

Between 2001 and 2004, 14% of in-flight interruptions havebeen attributed to ATA 21 chapter,environmental control system. They can be further divided asshown in the pie chart to the right.

The main reason for in-flightinterruptions linked to theenvironmental control system is theinability to pressurise the aircraft. The avionics equipment ventilationcomputer can cause inability topressurise by leaving the vent skinair valves open. This is addressed byproposal 1. Another cause ofpressurisation problems is majorleaks at pack level. Two packcomponents have been reinforced inthat respect. These are proposals 2and 3.

Miscellaneous events (21-00-00) aremainly smell or smoke reports withvarious origins not linked to the airconditioning. For example, an oilsmell due to an APU oil leak will belogged under ATA 21 as a first stepinstead of ATA 49.

Avionics ventilation (63%)

Air cooling (15%)

Pressurization (9%)

Miscellaneous (12%)

63%

12%9%

15%

21-26-00

21-00-0021-31-00

21-50-00

ATA 21 - AIR CONDITIONING

CrackContact

François GheurEnvironmental Control System Customer Services EngineeringTel: +33 (0)5 61 93 44 67Fax : +33 (0)5 61 93 44 [email protected]

Proposal 1ATA 21-26-00 ENHANCED AEVC

New AEVC PN 87292325V06

VSB 87292325-21-008Rev. 02 24-Jul-02• AIR CONDITIONING

AVIONICS EQUIPMENTVENTILATION COMPUTER87292325 – IMPROVEMENT OFTHE AEVC ADAPTATION TO ALLVALVES AND FANS, IMPROVEMENTOF TRANSPARENCY TIME(STANDARD V05)

Modification 31678Embodiment Rank MSN 1856

VSB 87292325-21-011Rev. 00 05-Apr-04• AIR CONDITIONING

AVIONICS EQUIPMENTVENTILATION COMPUTER87292325 – REDUCTION OFSMOKE WARNINGS (STANDARDV06)

Modifications 33967Embodiment Rank MSN 2290

SB 21-1147 Rev. 00 05-Apr-04• AIR CONDITIONING

AVIONICS EQUIPMENTVENTILATION – INSTALL THALESAEVC STANDARD V06

TFUs 21.26.00.019 and21.26.00.020

Proposal 2ATA 21-50-00 - PACK BELLOWS

New clamp PN NSA5532C612

SB 21-1155 planned for Sep-05• AIR CONDITIONING

INSTALL IMPROVED CLAMP ONBELLOWS AT PACK OUTLET ANDBETWEEN PACK OUTLET CHECKVALVE AND MIXER UNIT

Modification 35038Embodiment Rank MSN 2538

Proposal 3ATA 21-50-00 - CONDENSER

New condenser PN 756A0000-06

VSB 756A-21-04 Rev. 00 15 - Feb 05• AIR CONDITIONING

STRENGTH IMPROVEMENT OFSIDE PLATE

TFU 21.52.32.003

Resolves large portion of intermittent system failures.Improves dispatch reliability

+

None-

Cheap - Quick - Easy+

None-

Cheap modification+

Weight increase: approx.250gr/unit

-

AEVC and circuit board

Proposal 2ATA 21-50-00PACK BELLOWS

Rupture of clampshas caused pack bel-lows to break open,leading to cabin pres-surisation difficul-ties. Replacing theseclamps by corrosion-resistant and weldedones will minimizesuch occurrences.

Proposal 3ATA 21-50-00CONDENSER

Some pressurisation difficultieshave been linked to rupture of thecondenser (see example of rup-tured condenser below) of one airconditioning pack. The affectedpack will then no longer supply airto the cabin due to the significantleak at the rupture. The solutionhas been to increase the thicknessof the wall that exhibited this failure mode.

Example of afailed clamp

Example of a rupturedcondenser

ATA 21 - Air conditioning

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In 2004, 6% of all in-flightinterruptions have been attributedto ATA chapter 27. Constributorsare multiple but, as the chartshows, the two most significant areflaps and vibration.

The flap category represents thebiggest contributor to operationalinterruptions with 37% of the totalfor flight controls. This includesfaults that range from single SFCC(Slat and Flap Control Computer)faults with no effect on flap andslat availability, to faults that leadto flap/slat lock. Flap or slat lockhas a direct impact on landingdistance (defined in the FlightCrew Operating Manual).

Vibration is the second mostsignificant operational interruptioncontributor with 12%. It should benoted that vibration has no effecton handling or performanceefficiency: concerned surfaces andsystems remain fully efficientduring vibration events.

9%8%

37%5%12%

7%

22%

elac (9%)spoiler (8%)flap (37%)yaw damper (5%)vibration (12%)aileron (7%)other (22%)

ATA 27 - FLIGHT CONTROLSATA 27 - FLIGHT CONTROLS

Joan RenduEngineer Flight Control SystemsCustomer Services Engineering

ATA 27Flight controls

ATA 27 distribution (129 events Jan. 01 - Sept. 04)

Proposal 1 FLAP ROTARY ACTUATOR

There are 4 rotary actuators oneach wing. The function of theseactuators is to translate the rotarymotion of the flap drive shaft intomovement of the flaps.

Further to flap lock events, it wasreported in several cases that the

flap rotary actuators had recentlybeen removed for re-greasing.

Investigation revealed that duringaccomplishment of removalor installation of the flap rotaryactuators a slight mis-rigging in theflap transmission had beeninduced. This was found as a con-tributing factor in the reported flaplocks.

Contact

Joan RenduEngineer Flight Control SystemsCustomer Services EngineeringTel: +33 (0)5 62 11 01 42Fax: + 33 (0)5 61 93 44 25 [email protected]

Reduced maintenance+

Need to replace greasedactuator with semi-fluid one

-

Minimum cost, improvescommunication between flightcrew and maintenance

+

None-

Flap rotary actuator

Flap rotary actuators filled withgrease pre mod 28898 or pre mod28899 need removal for re-greas-ing approximately every 5 years(Refer to MPD task 275449-05-1).A new type of actuator post mod28898 or 28899 (post SB 27-1138)embodied since MSN 1256 arefilled with semi fluid and are ser-viceable on wing. This eases main-tenance and avoids removal/instal-lation of the actuators.

Proposal 2 VIBRATION

Airbus has adressed the majority ofairframe vibration sources.However, vibration related eventscan still occur and comprehensiveadvice for addressing them effec-tively is provided in the TroubleShooting Manual (TSM).

When the aircraft is on ground it isdifficult for maintenance to identi-fy the vibration source.

Effective troubleshooting of inflight vibration avoids vibration re-occurrence and associated poten-tial operational interruptions.

Rapid and efficient troubleshoot-ing requires accurate pilot report-ing using the vibration reportingsheet (entry point for TSM task 05-50-00-810-801).

It is important to note that for opti-mum troubleshooting efficiency,the flight crew should attempt toisolate the vibration source duringflight by modifying the flight para-meters (e.g. pitch, yaw, speed, etc.).

Note that the vibration reportingsheet also allows isolation of vibra-tion/noise from any source (e.g.flight controls, belly fairing seals,engines, doors etc).

Miscellaneous (56%)

Unknown (15%)

Ground Service andPTU Manifolds (8%)Hoses (15%)

Check Valve

Pressure Switch (5%)

in Manifold (3%)

5%3%15%

8%

15% 56%


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False low level (4%)

False low pressure (6%)

False/other (2%)

Low level (57%)

Low pressure (16%)

Overheat (10%)

Other (5%)

6%4%5%10%

16%

57%

2%

condition’ parts, Airbus recom-mends to carry out visual inspec-tions of these flexible hoses, andmore particularly those in specificand sensitive areas, such as the land-ing gear, landing gear doors, flightcontrols and the hydraulic bay.

During such an inspection, theinstallation of the line must bechecked (routing, clearances,clamp position/integrity), as wellas the integrity of the flexible hosesthemselves (see rejection criteria inthe following paragraph).

Wire-braided hoses/conduits haveto be replaced when:

• Two or more wires in one plaitor several wires are broken in aconcentrated area

• 10% or more of a given braidedarea exhibits wear from chafing

• Braid is protected by a neopreneoverlay and wear or chafing intothe braid has occurred.

To ease the operator’s integration ofsuch visual inspection in theirscheduled maintenance pro-grammes, Airbus has developed aCD-Rom, called ‘HydraulicSystems – Visual Inspection Guide’.It covers all the areas and equipmentthat could be checked and has beendeveloped in conjunction with oper-ators of the A320 Family.

Proposal 2HYDRAULIC PRESSURESWITCHES

Two types of pressure switch areinstalled on A320 Family aircraft:

• Engine pressure switches,located at the outlet port of bothGreen and Yellow EngineDriven Pumps (EDPs)

• And manifold pressureswitches, located on the HighPressure (HP) Manifolds

(Green, Yellow and Bluesystems), as well as at the outletport of the Blue Electric MotorPump (EMP).

Both types of switches have thesame general design, the main dif-ference being the warning thresh-old value, which is higher for theengine switch.

As shown in the main leak driverspie chart, the pressure switchescurrently installed can give somespurious low-pressure messages. Inaddition, hydraulic leakage fromthe switch itself was reported inpast years. It is estimated that over-all pressure switch failures haveled to 8.4% (for ATA 29) of the in-flight interruptions since 2001.

It has therefore been decided todevelop an enhanced design forboth pressure switch types to curethese issues. For this purpose:

• PN 450-1-3100-00 will replacePN 50-1-3100-00 on the EDPoutlet ports

• PN 450-2-3100-00 will replacePN 50-2-3100-00 on themanifolds and EMP outlet ports.

These units are still under the vali-dation process and will be avail-able for procurement mid-2005.

ATA 29 - HYDRAULIC SYSTEM ATA 29 - HYDRAULIC SYSTEM

Cédric TurroqueEngineer Hydraulic Systems


ATA 29Hydraulic system

A hydraulic system is usuallyconsidered lost when one of thefollowing cockpit messages is triggered:fluid quantity loss, fluid/pump overheator air/hydraulic low pressure (oroverpressure in a few cases). These caneither be the result of a spurious/falsefault message, or generated by aconfirmed system failure.

Hydraulic system loss alone does not necessarily lead to in-flightinterruption, as some operators (crews), in this situation, can choose to continuethe flight or not.

In 2004, 9% of in-flight interruptionswere attributable to ATA 29. For ourreview, we have divided the causes intotwo main categories:

• Interruptions due to hydraulic systemmalfunctions (i.e. false fault messages,overheat, low pressure, etc.). Theserepresent approximately 40% of thetotal in-flight interruptions for ATA29.

• Interruptions due to hydraulicleakages, which account for theremaining 60%.

Proposal 1FLEXIBLE HOSE INSPECTION

Flexible hoses are installed in thehydraulic distribution systemwhere movement is required and toease removal/installation of com-ponents. Pressure fluctuations, pul-sations of the system and bendingcycles impose a high level of stress

in the hose. In addition, some flex-ible hoses are subject to difficultenvironmental conditions, such astemperature variation, foreignobject damage, or chemical attacks(carbon burst, de-icing fluid etc.).If not replaced, damage to a hose orits wire braid, can lead to hydraulicleakage, and possibly system loss.Although flexible hoses are ‘on

Can be done during aircraftmaintenance check

+

Additional maintenance-

Proposal 2HYDRAULIC PRESSURE SWITCHES• Airbus Service Bulletin 29-1096:

‘INSTALL MODIFIED “EDP” SENSE LINE ON V2500ENGINES’

• TFU 29.11.17.001:‘EDP PRESS SWITCH FAILURE ON IAE V2500ENGINE’

• TFU 29.30.00.008:‘HYDRAULIC PRESSURE SWITCH LOWRELIABILITY’

Example of an illustration displayed on the‘Visual inspection Guide’ CD-Rom

'old' shape 'new' shape

Pressure Switch shape change

ATA 29 distribution

Main leak drivers forthe 57% low level items


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ATA 29 - HYDRAULIC SYSTEM ATA 29 - HYDRAULIC SYSTEM

For further information on theiravailability and to follow up Airbusactions, please refer to TFU29.30.00.008.

Please also refer to closed TFU29.11.17.001 (EDP PressureSwitch failure on IAE Engines),which introduces a new pressureswitch installation on IAE Enginesthrough Airbus SB 29-1096 andIAE SB V2500-NAC-0263.

Proposal 3GROUND SERVICE ANDPOWER TRANSFER UNIT(PTU) MANIFOLDS

Ground Service Manifold PN S4-3500272 is originally installedon aircraft pre-mod 25159(MSN<632).

The Power Transfer Unit ManifoldPN D2907019000200/400/600 areoriginally installed on aircraft pre-mod 27490 (MSN before 972).

The investigations carried out onseveral returned units of the abovePNs have led Airbus to publish

some recommendations, detailedin SIL 29-080, that describe thepreventive replacement of thesemanifolds.

PTU and Ground ServiceManifolds leakages represent 19%of in-flight interruptions due tohydraulic leakage for aircraft priorto MSN 972.

GROUND SERVICE MANIFOLDPRE-MOD 25159Airbus recommends that pre-mod25159 Green and Blue GroundService Manifolds, PN S4-3500272, are replaced by post-mod25159 Manifolds, PN S4-3500711,S4-3500712 or PN S4-350071Lbefore reaching 19,000 flightcycles (refer to SIL 29-077).

PTU MANIFOLD PRE-MOD 27490Airbus recommends that the pre-mod 27490 Yellow PTU manifoldsare replaced before reaching15,000 flight cycles:

• Either by the same model PND2907019000X00 with furtherreplacements scheduled within15,000 flight cycles

• Or by an improved PTUmanifold PN 1556A9900-01that has demonstrated enhancedfatigue endurance properties, by

Prevents spurious message andleakage

+

None-

Contact

Cédric TurroqueEngineer Hydraulic SystemsCustomer Services EngineeringTel: +33 (0)5 62 11 82 51Fax : +33 (0)5 61 93 32 [email protected]

Breakdown of ZCV66 Check-valve

embodying SB A320-29-1113.This requires somemodifications to the plumbinginstallation surrounding themanifold.

Proposal 4CHECK-VALVES IN HP/PTUMANIFOLD

Check-Valves PN ZCV66 andZCV67 are located in the HP andPTU Manifold pre-mod 27490, i.e.before MSN 972 (FINs 1059GM,1094GM, 2059GM, 3059GM &3094GM).

Further to several operator reportsof hydraulic leakage from check-valve ZCV66 / ZCV67, Airbus haslaunched investigations to deter-mine the root cause. Each time, itwas found that a retainer ring wasmissing on the leaking units, lead-ing to the cap loosening and subse-quent O-ring damage.

Two solutions are available to oper-ators:

• The preferred solution is toinstall a new check-valve, PN ZCV66-1/ZCV67-1, byAirbus SB 29-1107 (coveringCircle Seal Controls SBZCV66-29-1 & ZCV67-29-1)

• Otherwise, inspect, as per SB 29-1109, the alreadyinstalled check-valves andverify that the retainer rings arecorrectly fitted. If not, VSBZCV66-29-2/ZCV67-29-2 mustbe carried out to replace andsafety (Loctite) the retainer ring.

Two solutions availableEase of implementation

+

None-

Reduces leakage+

Scheduled replacement-

Retainer ring

50mm

PTU Manifold cracked

Proposal 3GROUND SERVICE ANDPOWER TRANSFER UNITMANIFOLDS• Airbus Service Bulletin 29-1113:

‘INTRODUCE LIEBHERR PTUMANIFOLD’

• Airbus Service Information Letter29-077:‘INTRODUCTION OF IMPROVEDGROUND SERVICE MANIFOLD(GSM) IN THE GREEN (FIN1146GM) AND BLUE (2146GM)HYDRAULIC SYSTEMS FOR PRE-MOD 25159 AIRCRAFT’

• Airbus Service Information Letter29-080:‘RECOMMENDATIONS FORPREVENTIVE REPLACEMENT OFTHE YELLOW PTU MANIFOLD ANDTHE GREEN AND BLUE GROUNDSERVICE MANIFOLDS’

• TFU 29.19.00.001:‘YELLOW SYSTEM GROUNDSERVICE MANIFOLD FAILURE’

• TFU 29.13.15.001:‘YELLOW SYSTEM – PTUMANIFOLD BODY CRACKS”

Proposal 4CHECK-VALVES IN HP/PTUMANIFOLD• Airbus Service Bulletin

29-1107:‘INSTALL MODIFIED CHECK-VALVES’

• Airbus Service Bulletin29-1109:

‘CHECK AND RE-INSTALLRETAINER RING ON CHECK-VALVE PN ZCV66/67’

Typical pipe installation


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ATA 32 - LANDING GEAR SYSTEMSATA 32 - LANDING GEAR SYSTEMS

Jérôme LesageEngineer A380 & A320 Family Landing gear


ATA 32Landing gear systems

ATA 32 IFTB number per FH and %

0.0

5.0

10.0

15.0

20.0

2001 2002 2003 2004

%

1.0E-05

1.0E-04

Nbr per FH (Log)ATA32%

ATA32 rate per FH

Two ATA32 key contributing factorshave been identified.

Landing gear non-retraction during

take-off phase is a key factor in in-flight

interruptions. It represents roughly 14% of

fleet reports. Although significant decrease

in rate has been demonstrated on ATA 32,

the large number of equipments involved in

the landing gear extension/retraction

sequence still gives a remote, but wide,

spread of failure modes.

The proposals given provide simple and

proven advice to significantly reduce ATA

32 related flight interruptions.

The first one, related to ground lock pins

and ground lock sleeves, commonly called

‘safety devices’, or ‘safety pins’, may

appear obvious. However, the increase of

flight interruptions reported due to safety

devices forgotten on the landing gear prior

to take off, combined with an increase of

queries on the subject led us to make

known Airbus operator experiences.

The other one relates to the nose landing

gear (NLG) ‘flight/ground’ indication

system. This item aims to address

improvements and thus to correct one of

the main contributing factors to landing

gear retraction failure.

Proposal 1GROUND LOCK SAFETYDEVICES

Installation of the landing gearsafety devices (ground lock pinsand collars), when the aircraft istowed or pushed-back duringflight operation is optional. Airbusdo not intend to make recommen-dations to favour one way or theother as some airlines requireinstallation of ground lock pinsand collars, whereas some do notwant to do this.

The rationale behind this optionalstatement is that during the A320Family operation, green hydraulicpower supply is generally ON, giv-ing two different means to physi-cally achieve the landing geardown and locked position:

• Gear architecture (nose landinggear over-centred position anddownlock springs),

• Green power supply at thedownlock actuators.

However, under towing operationfor maintenance, when the hydraulicpower supply is not available, onedownlock means is removed. Undersuch circumstances, Airbus recom-mends usage of the ground lock pinsand collars which are 100% reliableto ensure physical downlocking ofthe landing gear.

With regard to the above, Airbuswould like to highlight the follow-ing:

• Installation of the devices isoptional. It is not a requirementfor operational pushback (i.e.during turnaround)

• The devices are made visible(with a red flag for the pins) tothe ground crew. It remains theoperator’s responsibility tocheck they do not hangunderneath the aircraft prior todeparture

• It remains the airline’smaintenance staff responsibilityto ensure the red paint/flags arein good condition

• Some airlines who fit groundlock pins and collars duringturnaround have particularcheck-lists requesting theirflight crew to ask ground crewto show, in their hands, removedpins and collars prior to finaldispatch. This may be aneffective way to avoidinterruptions, if you wish toinstall those pins during shortturn arounds.

Ease of implementationLow cost

+

None-

Systems27%

32-40/32-5018%

Safety Pin8%

24/25GA11%

MLG3%

NLG5%

Hyd. Leaks6%

Equipment22%

Landing gear safety devices:ground lock pins and collars

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Proposal 2NOSE LANDING GEAR‘FLIGHT/GROUND’ INDICATING SYSTEM

The NLG ‘flight/ground’ indicat-ing system consists of a mechani-cal mechanism driving two sensors(FIN 24GA and 25GA) see figureabove. It indicates whether the air-craft is ‘in flight’ and ‘straight’(shock absorber extended and cen-tred) or ‘on ground’ (shockabsorber compressed or not‘straight’).

Three failure modes have beenidentified that induce bending orfatigue break of the sensors24/25GA rod links, which can leadto flight interruptions:

• Looseness of the NLG cover• Seizure/jamming of the rod links• Corrosion/seizure of the target

lever eye end bearings.

The following modifications havebeen defined to address these fail-ure modes:

• Cover fastening reinforcement(Messier-Dowty -Vendor Service Bulletin 580-32-3133)

• Rod links reinforcement(Messier-Dowty -Vendor ServiceBulletin 580-32-3157)

• Target lever modification to adda greasing path and then allowits lubrication (Messier-Dowty -Vendor- Service Bulletin 580-32-3155).

Both Vendor Service Bulletin 580-32-3155 and 580-32-3157 arecovered by Airbus Service BulletinA320-32-1288.

Pending embodiment of thesemodifications, some maintenancemay be applied to prevent the fail-ure mode of the rod eye end andtarget lever axle (refer to TFU 32-21-11-012): ‘Cleaning of the inter-face rod link axle as well as thetarget lever axle. If the target leveror the axles are removed, ensurethe axle lever torque value isbetween 4 and 5nm (2.949 to3.687lbf)’.

ATA 32 - LANDING GEAR SYSTEMS

A320 (Std 1)

856

2336

A321 (Std 2)

864

2363

A319 (Std 3)

860

2355

A318 (Std 4)

1660

2358

VSB 580-32-3133

SB A320-32-1288

Modification point of embodimentin production (MSN)

Contact

Jérôme LesageEngineer A380 & A320 FamilyLanding gearCustomer Services EngineeringTel: +33 (0)5 62 11 86 11Fax : +33 (0)5 61 93 32 [email protected]

Long term effectivenessCost effective

+

One grease point added to theNLG.

-

Rod link

Cover

Target lever

Two rod links configuration Single rod links configuration

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ATA 36 - ENGINE BLEED AIR SYSTEM

Proposal 1 BLEED AIR DUCTS LEAKS

Investigation revealed that bleedair ducts leaks represent 17% of in-flight interruptions. For this type offailure mode there are two possiblesolutions.

The first solution (considered as apreventive action) is the applica-tion of the MPD tasks for preven-tive seals replacement (ABS0737considered as the best reliable sealfrom previous design). These rec-ommendations are also describedin SIL 36-047.

Patrick GravePneumatics, Ice and Fire Protection


ATA 36Engine bleed air system

ATA 36 Distribution

During 2004, 8% of all in-flight

interruputions have been attributed

to ATA chapter 36. Analysis of these

interrruptions clearly shows that the

main causes are either bleed air duct

leak detection or bleed air over-

temperature regulation (leading to

single or double bleed loss). These

two main reasons are driving more

than 60% of ATA chapter 36

interruptions.

The main contributors

to these failure modes are well

identified and have fixes already

available:

• Temperature Control Thermostat

(TCT) failure is one major

contributor to the over-temperature

regulation (either TCT failure or

TCT filter clogging)

• Bleed air duct seal leakage for

bleed air leaks.

36%11%

11%

11%

15% 17%

Overtemp (36%)

Bleed leak (17%)

Bleed fault (15%)

Over pressure (11%)

Low pressure (11%)

Other (11%)

The newtechnologydeveloped

for the bleed air ductseals is also availablefor the air conditioningpacks through SB A320-21-1153 (availablesecond quarter of2005). It should benoted that bleed airleaks in the pack baywill trigger a wing leakwarning and as suchcontribute to ATA36reliability performance.

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Proposal 3 BLEED OVER-TEMPERATUREDUE TO TCT FILTERCONTAMINATION

Part of 51% of in flight interrup-tions (combined bleed fault andover-temperature).

Another well known possibility forbleed air over-temperature is theTCT filter clogging. To addressthis issue regular filter cleaning isrecommended and is availablethrough the application of the cor-responding MPD task. Today’s rec-ommended interval is 20 months.Nevertheless, depending on oper-ating environment and operator’sexperience, a less or a more fre-quent initial interval may be used.For example, it has been wellestablished that Middle East opera-tors were more affected than oth-ers. This recommendation is alsodescribed in SIL 36-055.

Contact

Patrick GravePneumatics, Ice and Fire ProtectionGroup ManagerCustomer Services EngineeringTel: +33 (0)5 61 93 43 13Fax : +33 (0)5 61 93 44 [email protected]


+

None-

Temperature Control Thermostat (TCT) Location

ATA 36 - ENGINE BLEED AIR SYSTEMFA

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The second solution offers a fargreater service life and is consid-ered the final fix. It incorporates anew design of bleed air duct seal,ABS1040, and is available throughSB A320-36-1043 (Modification32027, Embodiment rank MSN1830).

Proposal 2 BLEED OVER-TEMPERATUREDUE TO TCT FAILURE

Part of 51% of in flight interrup-tions (combined bleed fault andover-temperature). For informa-tion: bleed fault warnings can bedue to either an over-temperatureor an over-pressure. From experi-ence, it is considered that a largepart of bleed faults are due over-temperature and consequentlylinked to TCT behaviour.

The type of failure is known to bedue to a particular TCT PartNumber (PN). An improved PN isavailable to address this issue andapplication of a one-time TCTinspection, as per SB A320-36-1049, will allow the TCT PN to beidentified and replaced if required.


+

None-

Bleed air duct seal installation


+

None-

New seal design

Examples of TCTclogged filters

Ambient air

1

2

Bleed air

ABS1040-XXX

peri-seal Peri-airseal

NSA 8054 type

Peri-seal

ABS 0605 type

peri-seal

ABS 0632 type

peri-seal

ABS 0737 type

Male duct

Previous seals designs

Typical installation

Flange "A" Flange "B"

Flanges must be parallel( 2mm / 0.078in.)

"X"+-

ATA 36 - ENGINE BLEED AIR SYSTEM

TCT Filter

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ATA 21 - Air conditioning ATA 21 - Air conditioningATA 52 - DOORSATA 52 - DOORS

Arnaud Blanc-Nikolaïtchouk Structure Engineer Support


ATA 52Doors

No info (13%)

13%3%3%

11%

16%26%

28%

Handle recycled

Sensor replaced (26%)

Adjustment of switch (16%)

Connector loose (11%)

Mechanism readjusted (3%)

Other (3%)

or reajusted (28%)

Overall, for the year 2004, 6% of in-flight interruptions were attributed toATA chapter 52.

As far as doors are concerned, cargodoor false open warnings wereidentified as the main contributor toreported in-flight interruptions orrejected take off. In addition, analysisshows that, in most cases identifiedpreventive actions could have avoidedthese events.

In all cases, doors were confirmedclosed and locked afterwards.

Since the introduction of a newstandard of cargo door handlemechanism, the number of events hasbeen drastically reduced.

The major causes identified are:

• Cargo door handle deformed or cracked (old standard)

• Partial embodiment of SB A320-52-1039 (old standard)

• Proximity switch 28WV/34WV or30WV/32WV

• Handle hook mechanism jammed (old standard)

More detailed information on theseissues is provided in SIL 52-055.Trouble shooting information is givenin Trouble Shooting Manual 52-31-00.

7%1%16%

53%

13%

10%Pax doors (13%)

Emergency exits (10%)

Cargo doors (53%)

Access/service doors (16%)

MLG doors (1%)

Other (7%)

Cargo door distribution

24% 76.%

Reports on new handles (24%)

Reports on old handles (76%)

68% 32%

A/C with new handle (68%)

A/C with old handle (32%)

Detail of door handlemechanism

ATA 52 Distribution

Old/new handle distribution

TargetHandle

Proximityswitch28WV/34WV

Two types of cargo door handle canbe found on A319/A320/A321 air-craft. Mod 26213 introduced a newcargo door improved design, start-ing with MSN 759. From this MSN,a completely new design of handlewas introduced.

Although two thirds of aircraft inservice at the end of 2004 are fittedwith the new cargo door standard,reports on ‘old standard’ handlesrepresent more than 75% of thecases as you can see on the piechart on the following page.

Old/new handle Events distribution

Proposal 1 CARGO DOOR HANDLE

On pre-mod 26213 (old design) air-craft, the cargo door handle can bedeformed or cracked due to over-loading or impact damage. In thesecases, the proximity switch

28WV/34WV that monitors theposition of the handle can generate awarning.

This issue was initially addressedby mod 23213 that introduces areinforced handle on MSN 455,471, 513 to 516, 524 and subse-quent (SB A320-52-1039).

Cases were reported where a rein-forced handle is installed on a pre-mod 23213 aircraft as a replace-ment without full embodiment ofSB A320-52-1039. This SB con-sists of installing a reinforced han-dle and handle fitting, and rework-ing the handle mechanism. If apost-mod handle is installed on apre-mod aircraft without the mech-anism rework, interference mayoccur causing the handle to moveout of its recess, resulting in awarning being generated.

It is recommended to fully embodySB A320-52-1039 on pre-mod23213 aircraft. TFU 52.30.00.002also contains details on this point.

Old standard door handlefrom MSN001

Long term effectiveness+

None-

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Proposal 2 PROXIMITY SWITCH 28WV/34WV or 30WV/32WV

The proximity switches 28WV/34WV and/or 30WV/32WV canbecome incorrectly adjusted orfaulty. AMM procedure 52-71-00describes the cargo door proximityswitch adjustment procedures.

As a preventive action, some opera-tors have introduced a proximityswitch adjustment check, as perAMM 52-71-00, every C-check.

Introduction of an all metal sensorPN 8-933-01 improved the reliabil-ity of the sensors. The new all metalsensor is fully interchangeable withthe previous standard and is now thepreferred spare part.

Inductance check of the proximitysensors is covered by AMM task32-31-73 and allows their conditionto be assessed.

Proposal 3HANDLE HOOK MECHANISM

Cases of the handle hook mecha-nism (IPC 52-31-21) being stiff orjammed have been found. In thesecases, the hook does not engagecorrectly on the handle. Shouldsuch a situation occur, the handleflap will not be flush with the doorouter skin contour and generate awarning.

It is recommended to clean/lubri-cate the handle locking linkageevery C-check as per MPD523000-03-1 and AMM task 12-22-52-640-009.

ATA 21 - Air conditioning ATA 21 - Air conditioningATA 70-80 - PROPULSION SYSTEMATA 52 - DOORS

The review of each propulsionsystem reveals two common con-tributors to in-flight interrup-tions, which are Exhaust GasTemperature (EGT) and vibra-tion.

Several causes were identified,amongst them bird strike and EGToverlimit are the most numerous.Whereas bird strikes are hard toprevent, some EGT driven eventsmay be avoided through closetrend monitoring.

Generic proposals

The first generic proposal is toimplement an engine trend monitor-ing system. Low EGT margin con-ditions, as well as possible drift inengine behaviour can be monitoredand actions initiated before possibleevents occur.Secondly, in order to monitor fleetreliability and follow related enginereliability initiatives, we suggestcontacting Airbus CustomerServices Powerplant or your enginerepresentative.

More engine information is alsoavailable on:• www.cfm56.com• www.iae4u.com

Raquel Sanchez-GarciaA320 Family Propulsion System Engineer


ATA 70-80Propulsion system

Over the last four years the

number of events attributed to the

Propulsion System has regularly

decreased. In 2004, 14% of in-flight

interruptions were attributed to the

ATA chapters concerned (ATA 70 to

80). During these four years, well

over 900 aircraft have been

delivered (a fleet growth of amost

70%).

These events were reviewed for

each of the propulsion systems

employed in the A320 Family

(breakdown shown in the pie-chart)

to identify the main contributors

and proposals are provided

accordingly.

36%

23%35%

6%V2500-A1

CFM56-5AV2500-A5

CFM56-5B

Proximity switch30WV/32WV

ATA 70-80 distribution

Door sill

Proximity switch

Cargo door

Cargo door

Target

Target

Door sill Proximity switch

Pre-mod

Cargo door handle

A

Handle flap

Cargo door handle

Hook

Handle hookmechanism

Contact

Arnaud Blanc-NikolaïtchoukStructure Engineer SupportCustomer Services EngineeringTel: +33 (0)5 61 93 29 74Fax : +33 (0)5 61 93 36 [email protected]

Cheap and simple+

None-

Easy to implement+

None-


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V2500-A1 & A5ENGINEFor V2500-A1, EGT andvibration are the biggestcontributors to in-flightinterruptions with 27%and 13.4% respectively.With the exception of for-eign object related damagethe evolution in these parameterscan be monitored with a trendmonitoring system (see GenericProposals on page 21).

For V2500-A5, EGT and enginestalls are the biggest contributorswith 20% and 16% respectively.

Regarding stall events, two maindrivers were identified:

• HP Compressor 6: FleetManagement Plan completedsuccessfully (IAE NMSB 72-0445 - Airbus SB 72-1023)

• Variable Stator Vane system(VSV).

Proposal 1Compressor Vane VSVV2500-A5

Several cases of transitory ‘ENGCOMPRESSOR VANE’ warningshave been reported at Take Off (TO)to Climb (CLB) thrust transition, onhot days, on recently delivered air-craft, with no impact observed onmain engine parameters. In thesecircumstances, the warning is asso-ciated with ‘CHA(B) VSVACT/HC/EEC1(2)’ failure messagein the Post Flight Report, and‘SVATK’ in FADEC troubleshoot-ing data. This issue was initiallyidentified on engines below 2500flight hours since new, when theoutside air temperature was morethan 30°C. However, deeper under-standing proved that the issue ismore linked to flight cycles (FC)than flight hours and that:

• Occurrence rate shoulddrastically decrease after1,500FC,

• Occurrence rate shoulddrastically decrease below 25°C.

INTERIM MEASURESAlthough VSV actuator replace-ment and/or VSV system lubrica-tion may reduce the occurrencerate of the events, these actions arenot expected to fully clear theissue. Since warnings occurring inthe above conditions have noimpact on engine parameters, nospecific maintenance is requiredwhen this issue is experienced.Until recently, such alleviation ofmaintenance action had to be cov-ered on a case by case basis viaIAE One Time Concession (OTC).The Airbus TSM was updated tocover this for the Nov 04 revisionto reduce the maintenance burden.

CORRECTIVE ACTIONSIAE has identified an area of mar-ginality in fuel servo pressure ver-sus required VSV load at certainambient conditions and enginepower change conditions. Furtherinvestigation eventually led IAE toreview the following possible soft-ware fixes for this issue:

• Improvement of TO to CLBengine deceleration schedule, or

• Refinement of fault triggeringconditions, or

• Improvement of VSV controlschedule

Three possible FADEC softwarechanges are currently being evalu-ated by IAE. One of these changes,or a combination of these changeswill be incorporated in FADECsoftware SCN19 that is scheduledfor the beginning of 2006.

CFM56-5A & 5B ENGINES

For CFM56-5A engines during thelast four years Full AuthorityDigital Electronic Control(FADEC) faults are the biggestcontributor to in-flight interrup-tions (14.6%). Normally, thisincludes faults in the ElectronicControl Unit system (ECU).

Vibration is the second biggest con-tributor with 10.8%. In the majorityof cases this is attributed to LowPressure Turbine (LPT) and HighPressure Compressor (HPC) bladeForeign Object Damage (FOD).

For CFM56-5B during the last fouryears vibration (13%), N1 (LowPressure System Speed) fluctua-tions (8%) and compressor vane(8%) faults are the biggest contrib-utors to in-flight interruptions. Theevent causes are the T12 tempera-ture sensor and the air systemVariable Bleed Valve (VBV).

Proposal 1N1 fluctuationsT12 sensor temperatureCFM56-5B

The dual T12 temperature sensormeasures the engine inlet total airtemperature and the ECU in theengine power management logicuses this temperature value. TheT12 dual temperature sensor isinstalled on the fan inlet cowl andis connected to the ECU by branch-es of the harness HJ8 and HJ10.

Investigation has shown that vibra-tion can cause the wiring harnessand T12 sensor connectors to wearheavily. Connector wear generatesparticle liberation and contaminationand degrades the T12 sensor signal.

Engineering test-ing on-enginehas confirmedthe need for har-ness bracketmodification.

A new bracket(see illustrationon the left) will

be added to better support the har-nesses and the current bracket, madeof aluminium alloy, will be replacedby a stainless steel one. The modifi-cations may be done on wing and aService Bulletin and kit will be avail-able from the second quarter of 2005.

Proposal 2Compressor vaneAir System VBV Stop MechanismCFM56-5A & CFM56-5B

A numbers of events were reportedto be due to seized VBV stopmechanism. Investigation revealedthat a defined population of unitswere assembled with insufficientquantity of lubricant. The followingcorrective actions have been imple-mented:

• Production assembly manualrevised (Apr 04)

• Component Maintenance Manual75-31-22 TR 75-05 (Oct 04)issued

• Affected populationidentification: 1867 parts areaffected

• CFM Service Bulletin SB75-0062 (5A), & SB75-0030 (5B) toimprove VBV System reliability.Mobil 28 grease is introduced inthe VBV ballscrew actuators,replacing the Tribolube 2 grease.These SBs will be issued secondquarter 2005.

ATA 70-80 - PROPULSION SYSTEM ATA 70-80 - PROPULSION SYSTEM

8%13%

7%

6%

8%5%4%3%

2%

44% 4% 11%

10%

9%

10%6%15%

8.2%

27%

CFM56-5B in-flight interruptions ATA 70-80(98 events Jan 01 - Sep 04)

CFM56-5A in-flight interruptions ATA 70-80

27%

13%6%10%

37%

6%

19%

16%

10%

6%

2%

12%

31%

3%

Vibration

Compressor vane

Oil pressure

EGT

EPR

Compressor vaneEngine stall and

Oil quantity loss

Others

Oil clog

V2500-A5 IFTB and DV(142 events Jan 01 - Sep 04)

Contact

Raquel Sanchez-GarciaPropulsion System EngineerCustomer Services EngineeringTel: +33 (0)5 61 93 25 53Fax : +33 (0)5 93 44 [email protected]

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Vibration

N1 Fluctuations

Smoke

Oil pressure

Compressor vane

Oil leak

Oil quantity loss

Oil filter

Others

EGT Surge

Reverser

FADEC

V2500-A1 IFTB and DV ATA 70-80(56 events Jan 01 - Sep 04)

New additional brackets

Current bracket

Current bracket (aluminiumalloy) & new bracket(stainless steel

Ease of implementationMinimum cost

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Ease ofimplementationEffectiveness

ROI

Cost

Applicability


ROI

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ROI

012345 Cost

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ROI

Cost

Applicability


ROI

Cost

Applicability


ROI

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Air conditioning Pack bellow clamps

Hydraulic distribution SystemHose inspection

Air conditioning PackCondenser reinforcement

AEVC V06

Nose Landing GearFlight/Ground indicating system

Bleed air duct seals

Temperature Control Thermostat

A320 FAMILY - IN-FIGHT INTERRUPTION REVIEW - CONCLUSION

GUIDE TO CHARTS

A graphical assessment is provided for those proposals with a particularly wide interest.

There is one chart for each proposal and each assesses the relative merits of each proposal against the five criteria as follows:• Cost . . . . . . . . . . . . . . . . . . 5 = Low 1 = High• Applicability . . . . . . . . . . . . . 5 = Wide 1 = Limited• Ease of implementation . . . . 5 = Easy 1 = Complex• Effectiveness . . . . . . . . . . . . 5 = High 1 = Low• ROI (Return On Investment) . 5 = Short period 1 = Long term

In short, the greater the area covered the higher the overall interest.

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A320 FAMILY - IN-FIGHT INTERRUPTION REVIEW - CONCLUSION

As this FAST Special has explained,

an in-flight interruption is a rare

event and, for the A320 Family, the

rate continues to fall. Nonetheless,

these events are unquestionably

significant for any aircraft operator.

The ongoing process of identifying

reliability drivers continues. Airbus

and its vendors will also continue to

offer new enhancements as needs

and opportunities appear.

The current fleet of the A320 Family

is operated by approximately 150

different organizations. Today, on

average, an aircraft of the A320

Family experiences an in-flight

interruption approximately once

every 7000 flights. For an operator of

six aircraft with average utilisation

this suggests one in-flight

interruption event every four or five

months.

ConclusionFor this FAST Special, analysis ofthe events recorded during the lastfour years has been carried out.This has allowed proposals thatwill be applicable to the greatestnumber of operators to be identi-fied. However, as might be expect-ed for a mature aircraft family, theroot causes are widely spread.Nonetheless, some proposals standout as having a wide applicabilityand offer a significant contributionto further in-flight interruptionreduction. In addition, most pro-posals offer an intrinsic improve-ment in overall system reliabilitythat should not be forgotten whenconsidering their implementation.

The recently available standardV06 of the Avionic EquipmentVentilation Computer, (AEVC),described on page 4, addresses anumber of issues that have been atthe root of a relatively high per-centage of in-flight interruptions.

Similarly, the Temperature ControlThermostat (TCT), described onpage 17, has also been identified asbeing the cause of a relatively highnumber of events, particularly whenoperating in dusty environments.

Other proposals that are consideredto be of particular interest are:

• Nose Landing GearGround/Flight IndicatingSystem (page 14)

• Bleed Air Duct seals(page 15 and 16)

• Air Conditioning PackBellows clamps (page 5)

• Air Conditioning PackCondenser reinforcement (page 5)

• Hydraulic Hose inspection(page 8 and 9)

Implementation of any one of theproposals in this FAST Specialapplicable to your airline and itsfleet will reduce the number of in-flight interruptions.

Should there be any questions con-cerning the contents of this docu-ment please do not hesitate to con-tact the author of the relevant ATAchapter, your Regional CustomerServices Manager (RCSM) or yourCustomer Services Director(CSD).

Documents

FAST magazine Special A320 - May 2005 - · PDF file05.04.2004 · as airlines strive to further optimize aircraft utilisation and minimize costs, ... chapters the ATA drivers are identi-fied