Arriel_1 12-00 En

ARRIEL 1ARRIEL 1 TURBOSHAFTENGINE

Training manualDecember 2000

Ref.: X 292 87 960 2

0.1Edition : December 2000

Training Manual ARRIEL 1

For training purposes only© Copyright - TURBOMECA - 2000

FOREWORD

This document provides, in a teaching form, all the informa-tion required for the operation and the maintenance of theARRIEL 1 Turboshaft engine for training purposes only.

It will not be updated, and if required, modifications will beincluded in a new issue.

TURBOMECA Training Centre

This document is the property of TURBOMECA and it may not be copied without the express authority of TURBOMECA.

FOREWORD




SUMMARY

0 - Foreword

1 - Introduction

2 - Power plant

3 - Engine

4 - Oil system

5 - Air system

6 - Fuel system

7 - Control system

8 - Control and indication

9 - Starting

10 - Electrical system

11 - Engine installation

12 - Operating limitations andprocedures

13 - Various aspects of maintenance

14 - Maintenance procedures

15 - Fault analysis and troubleshooting

16 - Checking of knowledge

SUMMARY




TABLE OF CONTENTS0 - FOREWORD

- Summary ............................................ 0.2

- Table of contents ................................ 0.3

- List of abbreviations .......................... 0.7

- Conversion table ................................ 0.10

1 - INTRODUCTION- General information ........................... 1.2

- Training method ................................. 1.4

- Training aids ...................................... 1.6

- Training programme ......................... 1.8 to 1.12

2 - POWER PLANT- General presentation ......................... 2.2

- General description ........................... 2.4

- General operation .............................. 2.8

- Principle of adaptation to helicopter .. 2.12

- Main characteristics ........................... 2.14

- Design and development ................... 2.22 to 2.27

3 - ENGINE- Engine ................................................ 3.2

- Axial compressor ............................... 3.8

- Gas generator HP section ................... 3.14• Centrifugal compressor ................... 3.16• Combustion chamber....................... 3.22• Gas generator turbine ...................... 3.28

- Power turbine ..................................... 3.34

- Exhaust pipe ....................................... 3.40

- Reduction gearbox ............................. 3.42

- Transmission shaftand accessory gearbox ....................... 3.48

• Transmission shaft - twin-engineversion ............................................. 3.50

• Transmission shaft - single engineversion ............................................. 3.52

• Accessory box ................................. 3.54 to 3.61

4 - OIL SYSTEM- Oil system ......................................... 4.2

- Lubrication ........................................ 4.8

TABLE OF CONTENTS




TABLE OF CONTENTS(CONTINUED)

4 - OIL SYSTEM (CONTINUED)- Oil tank ............................................. 4.12

- Oil pumps ........................................... 4.14

- Electrical magnetic plugs ................... 4.20

- Oil filter .............................................. 4.24

- Filter pre-blockage indicator .............. 4.30

- Oil cooler ........................................... 4.34

- Centrifugal breather ........................... 4.36

- Magnetic plugs ................................... 4.40

- Strainers ............................................. 4.42

- Indicating devices .............................. 4.44

- Oil pipes and ducts ............................. 4.50 to 4.51

5 - AIR SYSTEM- Air system ......................................... 5.2

- Internal air system ............................. 5.4

- Air tappings........................................ 5.8

- Compressor bleed valve ..................... 5.10

- Air tapping unions ............................. 5.18

- Air pipes ............................................. 5.20 to 5.21

6 - FUEL SYSTEM- Fuel system ....................................... 6.2

- Fuel Control Unit ............................... 6.12

• Fuel pump........................................ 6.14• Fuel filter ......................................... 6.18• Manual control ................................ 6.24• Metering unit ................................... 6.28

- Overspeed and drain valve ................ 6.30

- Start injector electro-valve ................. 6.36

- Main injection system ........................ 6.42

- Start injectors ..................................... 6.46

- Combustion chamber drain valve ...... 6.50

- Fuel pipes ........................................... 6.54 to 6.55

7 - CONTROL SYSTEM- Control system ................................... 7.2

• General ............................................ 7.2• Description ...................................... 7.4• Operation ......................................... 7.6 to 7.33

TABLE OF CONTENTS





8 - CONTROL AND INDICATION- Manual control system ....................... 8.2- Indicating system ............................... 8.6- Speed indication ................................. 8.8- Tachometer transmitters ..................... 8.10- Speed probes (1E, 1K, 1S versions) .. 8.14- Gas temperature indication ................ 8.16- Thermocouple probes ........................ 8.18- Thermocouple junction box

(1S version) ........................................ 8.20- Torque indication ............................... 8.22- Torquemeter ....................................... 8.24- Torque transmitter .............................. 8.26- Miscellaneous indications .................. 8.28 to 8.35

9 - STARTING- Starting system ................................... 9.2- Starter ................................................. 9.10- Ignition system ................................... 9.16- Ignition units ...................................... 9.18- Igniter plugs ....................................... 9.22- Ignition cables .................................... 9.26 to 9.27

10 - ELECTRICAL SYSTEM- Electrical system ................................ 10.2- Electrical accessories ......................... 10.4- Power turbine overspeed safety

system ................................................ 10.6- Power turbine overspeed sensor ........ 10.10- Tachometer box.................................. 10.14- Super contingency power system ...... 10.24- Electrical harnesses ............................ 10.28 to 10.29

11 - ENGINE INSTALLATION- Engine compartment .......................... 11.2- Engine mounting ................................ 11.4- Power drive ........................................ 11.8- Air intake ........................................... 11.10- Exhaust system .................................. 11.12- Engine system interfaces ................... 11.14

• Oil system........................................ 11.14• Aircraft LP fuel system ................... 11.16• Manual controls ............................... 11.18• Air system ....................................... 11.20

- Drain system ...................................... 11.22- Fire protection .................................... 11.24 to 11.25

TABLE OF CONTENTS





12 - OPERATING LIMITATIONS ANDPROCEDURES

- Operating limitations ......................... 12.2

- Operating procedures ........................ 12.6 to 12.9

13 - VARIOUS ASPECTS OF MAINTENANCE- Maintenance concept ......................... 13.2

- TBOs and life limits ........................... 13.4

- Preventive maintenance ..................... 13.6

- "On-condition" monitoring ................ 13.8

- Corrective maintenance ..................... 13.10

- Lubricants - Fuels - Materials ............ 13.12

- Tooling ............................................... 13.14

- Technical publications ....................... 13.16

- Product support .................................. 13.22 to 13.23

14 - MAINTENANCE PROCEDURES- General ............................................... 14.2

- Inspection and check procedures ....... 14.4

- Removal and installation procedures . 14.52

- Deep maintenance .............................. 14.62- Repair and overhaul ........................... 14.64 to 14.65

15 - FAULT ANALYSIS AND TROUBLESHOOTING

- Fault analysis ..................................... 15.2- Trouble shooting ................................ 15.32 to 15.47

16 - CHECKING OF KNOWLEDGE- Introduction ........................................ 16.2- Questionnaire 1 ................................. 16.3- Questionnaire 2 ................................. 16.6- Questionnaire 3 ................................. 16.12- Questionnaire 4 .................................. 16.15 to 16.30

OBSERVATIONS ................................... Last page

This training manual is established to meet trainingrequirements and takes into consideration, to a certain extent,ATA 104 specifications.

This document has 562 pages. It was produced using adesktop publishing system.

TABLE OF CONTENTS




FAA .............. Federal Aviation AdministrationFCU .............. Fuel Control UnitFMU ............. Fuel Metering UnitFOD .............. Foreign Object Damageft .................... FeetFWD ............. ForwardG ................... Mass air flowg .................... GramHE ................. High EnergyHP ................. Horse PowerHP ................. High PressureHUMS........... Health and Usage Monitoring SystemHz ................. HertzICP ................ Intermediate Contingency PowerID .................. IdentificationIFDS ............. Integrated Flight Display SystemILS ................ Integrated Logistic SupportISA ................ International Standard AtmosphereISV ................ Servo-valve intensity

A/C ............... AircraftAC................. Alternating CurrentACMS ........... Automatic Control Monitoring SystemACW ............. Anti-clockwiseAEO .............. All Engines OperatingATA .............. Air Transport AssociationBITE ............. Built In Test EquipmentTq (C) ........... Torquecc/h ............... Cubic centimetres per hourFCV .............. Frequency/Voltage ConverterCH................. Hourly Fuel consumptioncSt ................. CentistokeCW ................ ClockwisedaN ............... DecaNewtondB ................. DecibelDC................. Direct CurrentDGAC ........... Direction Générale de l'Aviation CivileEc .................. Kinetic energyEGT .............. Exhaust Gas Temperature

LIST OF ABBREVIATIONS

The abbreviations / symbols shown below may be used during training :






(CONTINUED)

kHz ............... KilohertzkPa ................ KilopascalkW ................ Kilowattl/h .................. Litre per hourlb ................... Poundlb/HP.hr ........ Pounds per Horse Power per hourlb/hr ............... Pounds per hourlb/sec. ............ Pounds per secondLRU .............. Line Replaceable UnitLTT ............... Learning Through TeachingLVDT ........... Linear Voltage Differential Transducerm ................... MetremA ................ MilliampereMAX ............. MaximumMCP .............. Max Continuous PowerMCQ ............. Multi Choice QuestionnaireMGB ............. Main gearboxMHz .............. Mega HertzMIN .............. Minimummm ................ MillimetremP ................. Micro-processor

MTBF ........... Mean Time Between FailureMTBUR ........ Mean Time Between Unscheduled RemovalMTCP ........... Maintenance Test Control PanelMTTR ........... Mean Time to RepairmV ................ MillivoltN ................... Rotation speedN1 ................. Gas generator rotation speedN2 ................. Power turbine rotation speedNMD ............. Navigation and Mission DisplayNOVRAM .... Non Volatile Random Access MemoryNR................. Rotor rotation speedω ................... Angular VelocityO/S ................ OverspeedOEI ............... One Engine InoperativeP .................... PressureP2 .................. Compressor outlet pressurePOS ............... PositionPPM .............. Parts per millionPSI ................ Pounds per Square InchPSIA ............. Pounds per Square Inch AbsolutePSID ............. Pounds per Square Inch Differential






(CONTINUED)

PSIG ............. Pounds per Square Inch GaugePT ................. Power TurbineQ ................... Fuel flowRAM ............. Random Access MemoryROM ............. Read Only MemoryRPM .............. Revolutions Per MinuteRTD .............. Resistive Temperature DeviceSCP ............... Super Contingency powerSFC ............... Specific Fuel ConsumptionShp ................ Shaft horse powerSI ................... International SystemSRU .............. Shop replaceable unitt ..................... TimeT/O ................ Take-OffTBO .............. Time Between OverhaulsTET ............... Turbine Entry TemperatureTM ................ Turbomecat° ................... Temperaturet4 ................... Gas temperature

US G ............. US GallonVAC .............. Volt, Alternating CurrentVDC .............. Volt, Direct CurrentW .................. PowerXTL .............. Throttle position signalXCP .............. Collective Pitch SignalZ .................... AltitudeZp .................. Pressure altitude°C .................. Degrees Celsius°F .................. Degrees Fahrenheit°K.................. Degrees Kelvin± .................... Plus or MinusΩ ................... Ohm∆ .................... Difference (delta)∆P ................. Pressure difference% ................... Percent< .................... Is lower than> .................... Is higher than





1 mm = 0.039 inch1 m = 3.28 ft = 1.09 yard

1 dm3 = 1 litre = 0.26 US gallon

1 kg = 2.2 lbs

1 kW = 1.34 HP

° C = (°F-32). 5/9° K = [(°F-32)5/9] + 273

1 kPa = 0.01 bar = 0.145 PSI

1 kg/s = 2.2 lbs/sec.

1 g/kW.h = 0.00164 lb/HP.hr

Length

Volume

Mass

Power

Temperature

Pressure

Flow (air, oil, fuel)

Specific Fuel Consumption

CONVERSION TABLEUNIT International System British or American Systems

CONVERSION TABLE



For training purposes only© Copyright - TURBOMECA - 2000 INTRODUCTION

1-INTRODUCTION

- General information...................................................... 1.2

- Training method ............................................................ 1.4

- Training aids .................................................................. 1.6

- Training programme .................................................... 1.8 to 1.12




INTRODUCTION

GENERAL INFORMATION

«The power of knowledge»

Adequate training is essential for obvious safety reasons,but also to reduce additional maintenance costs incurredby unjustified removals and excessive downtime.

"Greater knowledge leads to greater efficiency".

Objectives of training

The main objective is the acquisition of the knowledgerequired for the tasks to be achieved (know and knowhow).

Further information is also communicated to widen theskill and the experience of the trainee.

Training approach

- Performance based training according to taskanalysis, with classroom sessions, student involvement,practical work and troubleshooting techniques

- Advanced training aids : training manual, ComputerAided Presentation (or overhead projection), multimediacourseware and demonstration mock-ups

- Experienced and formally trained instructors

- Courses are taught in English and French and, inspecial circumstances, in German and Spanish.

Training Centre

The Training Centre is located in one of the buildings ofTURBOMECA's TARNOS factory.

TARNOS .... 5 kms north of the BAYONNE -ANGLET - BIARRITZ district - Accessby train (BAYONNE station), by plane(BIARRITZ-PARME airport), by road(A63 highway, TARNOS exit).

Address ...... TURBOMECA - 40220 TARNOSFRANCE

Telex ........... 570 042

Telephone .. (33) 5 59 74 40 07 or 05 59 74 40 07

Fax .............. (33) 5 59 74 45 15 or 05 59 74 45 15

E-mail ......... [email protected]

The training centre is organized in order to answer totraining demands (administration, training aids,instructors).

Training sites

Training courses are also conducted in subsidiaries, inapproved training centres and on site :- by a TURBOMECA qualified instructor, in certain

subsidiaries and approved training centres- or by an instructor detached from TURBOMECA France,

in our subsidiaries and in the clients' premises.




GENERAL INFORMATION

PARIS

TARNOS

BORDES

SPAIN

FRANCE

BAYONNE

ATLANTIC

OCEAN

TRAININGOBJECTIVES OF TRAINING

TRAINING APPROACH

«The power of knowledge»

Adequate training is essential for obvious safety reasons, but also to reduce additional

maintenance costs incurred by unjustified removals and excessive downtime.

"Greater knowledge leads to greater efficiency".

TRAINING SITES

Training courses are alsoconducted in subsidiaries, in

approved training centres and on site.

TRAINING CENTRE,TURBOMECA Tarnos

(FRANCE)




INTRODUCTION

TRAINING METHOD

Knowledge transmission process

The required knowledge is transmitted in such a mannerthat the student may use it efficiently in variouscircumstances.

The training is conducted in accordance with a processwhich considers :

- A phase of explanation for understanding

- A phase of assimilation leading to the complete acqui-sition and long-term retention of the knowledge.

Continuous checking of knowledge helps to ensure theinformation is assimilated. It is more a method of workthan a testing in the traditional sense (refer to chapter 16).

Training method

The training method is a carefully balanced combinationof :

- Lecture

- Discussions

- Exercises

- Practical work.




TRAINING METHOD

1

4 3

2

KNOWLEDGETRANSMISSION PROCESS

TRAINING METHOD

1 - LECTURE

2 - EXERCISES

3 - DISCUSSIONS

4 - PRACTICAL WORK

INSTRUCTOR

MEDIA

STUDENT

EXPLANATION ASSIMILATION

KNOWLEDGE TRANSMISSION,PHASES :

- Explanation

- Assimilation

CHECKING OF KNOWLEDGE :

- Continuous checking, treated in

chapter 16




INTRODUCTION

TRAINING AIDS

Training manual

The training manual is the basic source of information.

It contains, in a teaching form, all required informationand explanations, following a layout derived from theATA 104 standard. Thus each subject is treated followinga plan which allows the material to be adapted to differentlevels of training.

Typical plan :

- General (function, position, main characteristics, maincomponents)

- Description (general and detailed)

- Operation (phases, synthesis).

Other technical publications are also used during a course.

Computer Aided Presentation or overheadprojection

Computer Aided Presentation or overhead projection isused to display the illustrations contained in the trainingmanual (the instructor's explanations follow the manual).

Multimedia courseware

Interactive courseware is used to transmit informationduring a course.

This multimedia system uses text, photos, illustrations,animation and video.

Certain courses are available for sale on CD-ROM.

This system with quick and easy access can be veryefficient for maintaining knowledge levels in the workplace.

However, only a course delivered by a TURBOMECAinstructor or TURBOMECA qualified instructor wouldallow the issue of an engine maintenance authorisationcard.

Demonstration mock-ups

Demonstration mock-ups are also used for componentidentification and maintenance procedures.

Note : The information contained in the Training Aidsmust be considered for training purposes only.




TRAINING AIDS

MULTIMEDIACOURSEWARE

DEMONSTRATIONMOCK-UPS

COMPUTER AIDED PRESENTATIONOR OVERHEAD PROJECTION

TRAINING MANUAL

Note : The information contained in

the Training Aids must be considered for training

purposes only.




INTRODUCTION

TRAINING PROGRAMME

The course programme follows the manual. However, itshould be noted that the "classroom sessions" alternatewith periods devoted to demonstrations and practicalwork.

According to the contents, each session is mainly devotedto description and operation.

The engine maintenance aspect is mainly covered by thelast part of the manual, which also deals with variouselements related to maintenance (standard practices,technical publications, logistics and mainly fault analysisand fault finding).

Examples of programme :

The following pages provide examples of trainingprogramme :

- Familiarization course

- 1st line maintenance (O level) : preventive and correctivemaintenance

- 2nd line maintenance (I level) : modules, SRU

- 3rd line maintenance (H level) : deep maintenance

- 4th line maintenance (D level) : repair or overhaul.




FAMILIARIZATION COURSE

Objective : At the end of this course, the student will be able to describe the engine, to explain its principle of operationand to identify the main components of the engine and systems.

Programme :

- Engine systems (continued)

- Main aspects of maintenance

- Revision - Checking of knowledge

FIRST DAY

SECOND DAY

- Introduction

- General presentation of the engine

- Engine description

- Engine systems




INTRODUCTION

1st LINE MAINTENANCE COURSE (O LEVEL) : PREVENTIVE AND CORRECTIVE MAINTENANCE

Objective : At the end of this course, the student will be able to identify the engine components, to describe and toexplain the operation of the engine and its systems, to carry out 1st line maintenance procedures and todiagnose operating failures.

Programme :

FIRST DAY- Introduction - General

- Engine presentation - Engine description - Oil system

THIRD DAY

FOURTH DAY

SECOND DAY

FIFTH DAY

- Air system - Fuel system - Control system

- Measurement and indicating systems - Starting

- Electrical system - Engine installation

- Operating limitations and procedures - Various aspects of maintenance

- Maintenance procedures - Trouble shooting

- Visits - Revision

- Examination - Miscellaneous questions




2nd LINE MAINTENANCE COURSE (I LEVEL) : MODULES, SRU

Objective : At the end of this course, the student will be able to identify the engine components, to carry out all the2nd line maintenance procedures (mainly the removal/installation of modules and shop replaceable unit).

Programme : The programme mainly includes practical work. This programme can be carried out after the 1st linemaintenance programme.

- Introduction

- Revision (if this course is not conducted directly after the 1st linecourse)

- Removal of modules

FIRST DAY

SECOND DAY

THIRD DAY

- Removal of modules

- Inspection and check of modules

- Installation of modules

- Inspection and checks after installation




INTRODUCTION

3rd LINE MAINTENANCE COURSE (H LEVEL) : DEEP MAINTENANCE

Objective : At the end of the course, the trainee will be able to carry out the 3rd line maintenance procedures (deepmaintenance).

Programme :

4th LINE MAINTENANCE COURSE (D LEVEL) : REPAIR OR OVERHAUL

Objective : At the end of the course, the trainee will be able to carry out the specific tasks regarding the engine andrelated to his skills (eg : control system, assembly, machining procedures...).

Programme :

- Introduction

- Definition of procedures

- Practical work

FROM 3 DAYS TO 3 WEEKS

- Introduction

- Definition of procedures

- Practical work

SEVERAL WEEKS



For training purposes only© Copyright - TURBOMECA - 2000 POWER PLANT

2-POWER PLANT

- General presentation .................................................... 2.2

- General description ...................................................... 2.4

- General operation ........................................................ 2.8

- Principle of adaptation to helicopter ........................... 2.12

- Main characteristics ..................................................... 2.14

- Design and development .............................................. 2.22 to 2.27

Edition : December 2000For training purposes only© Copyright - TURBOMECA - 2000


POWER PLANT2.2

GENERAL PRESENTATION

Function

The power plant provides power by transforming theenergy contained in the air and fuel into shaft power.

Main characteristics

- Type : free turbine turboshaft engine, front power drive,external power transmission shaft

- Concept : modular

- Output shaft speed: 6000 RPM (at 100 %) (except the1S1)

- Mass ≈ 126 kg (277 lbs). The mass may vary accordingto the engine versions.




GENERAL PRESENTATION

POWER

AIR GAS

FUEL

6000 RPM at 100 %(except 1S1)

POWER PLANT

- Free turbine type

- Modular

- Mass ≈ 126 kg (277 lbs)



POWER PLANT2.4

ENGINE GENERAL DESCRIPTION

This description considers the main functional componentsof the engine.

Gas generator

- Single stage axial compressor

- Centrifugal compressor

- Annular combustion chamber with centrifugal fuelinjection

- Two stage axial turbine.

Power turbine

- Single stage axial turbine.

Exhaust pipe

- Elliptical, axial exhaust pipe.

Reduction gearbox

- Reduction gearbox comprising three helical toothedgears.

Transmission shaft

- External shaft located in a protecting tube which connectsthe reduction gearbox to the accessory gearbox.

Accessory gearbox

- Gearbox containing the accessory drive train and themain power drive.




ENGINE GENERAL DESCRIPTION

ACCESSORYGEARBOX

GAS GENERATOR

Axialcompressor

Centrifugalcompressor

Combustionchamber

Turbine

POWER TURBINE EXHAUST PIPE

REDUCTION GEARBOXTRANSMISSION SHAFTMAIN POWER DRIVE



POWER PLANT2.6

ENGINE SYSTEMS - GENERAL DESCRIPTION

This part deals with the systems and functions of theengine.

Oil system

The oil system lubricates and cools the engine components.

Dry sump system, synthetic oil, tank and cooling unitinstalled on the aircraft. Pressure, temperature and magneticparticles indications.

Air system

Internal system to pressurise and cool engine internalparts. Accessory air supply system (ventilation of startinjectors, engine control). Compressor bleed valve. Airsupply to the aircraft.

Fuel system

Fuel supply through a gear type pump. Delivery through ametering unit and a valve. Start injection through 2 simpleinjectors. Main injection by a centrifugal wheel.

Control system

Constant power turbine rotation speed. Accelerationcontrol. Miscellaneous protection systems.

Hydro-mechanical control system (with a mechanicalback-up manual control) using fuel as hydraulic fluid.

Engine handling procedure

Entirely automatic. Control lever to start, stop and foremergency control.

Engine indicating

Rotation speeds. Gas temperature. Engine torque. Oiltemperature and pressure. Miscellaneous indications.

Starting

Cranking by an electric starter. Ignition by High Energy.Manual control.

Electrical system

Starting system. Indicating system. Overspeed system.Harness with two or three connectors according to version.

Engine installation

- Interfaces designed for quick removal and installationof engine

- Front and rear supports. Lifting rings

- Miscellaneous equipment (air intake, exhaust, firewalls,transmission shaft, air bleeds, drains, fire protection).




ENGINE SYSTEMS - GENERAL DESCRIPTION

OIL SYSTEMAIR SYSTEM

FUEL SYSTEM

ENGINEHANDLING PROCEDURE

ENGINE INDICATINGSTARTING

ELECTRICAL SYSTEM

ENGINE INSTALLATION

FWD

CONTROL SYSTEM



POWER PLANT2.8

GENERAL OPERATION

This part deals with the basic operation of the engine.

Gas generator

- Compression of the air in the axial and centrifugalcompressors

- Combustion of the fuel/air mixture in the annularcombustion chamber

- Gas expansion in the gas generator turbine which drivesthe compressors and engine accessories.

Power turbine

- Expansion of the gas in the single stage turbine whichdrives the output shaft through the reduction gearbox.

Exhaust

- Discharge overboard of the gas.

Reduction gearbox

- Drive, at reduced speed, to the transmission shaft.

Transmission shaft

- Transmission of the power from the reduction gearboxto the output shaft.

Accessory gearbox

- Power take-off to drive the helicopter main gearbox

- Drive of the accessories by the gas generator through abevel gear, a vertical drive shaft and a gear train.




GENERAL OPERATION

GAS GENERATOR

COMPRESSION COMBUSTION EXPANSION

POWER TURBINE

GAS EXHAUST

REDUCTION GEARBOXTRANSMISSION SHAFT

ACCESSORY GEARBOX

EXPANSION

DRIVE SPEED REDUCTION

AIRINLET

ACCESSORYDRIVE

POWERDRIVE

FORWARD POWER TRANSMISSION

FUEL



POWER PLANT2.10

OPERATION - ADAPTATION

This part deals with the parameters and the adaptation ofthe gas generator and power turbine.

Component adaptation

For the engine operation, two functional assemblies can beconsidered :

- The gas generator which provides kinetic energy

- The power turbine which transforms the kinetic energyinto mechanical power on a shaft.

The two assemblies have different rotation speeds.

Gas generator

The gas generator operation is defined by :

- The air mass flow G (air flow which enters the engine)

- The air pressure P2 and air temperature t2 at thecentrifugal compressor outlet

- The fuel flow Q injected into the combustion chamber

- The gas temperature TET at the turbine entry

- The rotation speed N1 of the gas generator

- The kinetic energy Ec supplied to the turbine.

Power turbine

The power turbine operation is defined by the balancebetween the power received from the gas generator and thetorque applied on the shaft, that is the torque C and therotation speed N2.

Operation

The operation is represented by the diagram which showsthe power W, the rotation speeds N1 and N2 and the maxtorque limit C imposed by the mechanical transmission :

- The torque C is a function of the N2 rotation speed

- The power W is equal to the torque C multiplied by theangular velocity ω

- At constant N2 speed, the power is only a function of thetorque

- The engine parameters can be represented as a functionof a reference parameter ; N1 for example.




COMPONENT ADAPTATION

OPERATION - ADAPTATION

G(air mass flow)

N1(rotation speed)

N2 rotation speed(constant)

C(shaft torque)

Q(fuel flow)

TET(turbine entry temperature)

P2, t2(compressor outlet

pressure and temperature)

Ec(kineticenergy)

W(shaft power)

GAS GENERATOR POWER TURBINE

W

N2

Max torque

IsospeedsN1

C

N2

ENGINEPARAMETERS

N1

G

P2/P0

WCH

TET

SFC

Power W and speeds N1, N2 P2/P0: Compression ratioCH : Hourly fuel consumptionSFC : Specific fuel consumption

Torque as a function of N2

W = C . ω

ω = 2 π N60



POWER PLANT2.12

PRINCIPLE OF ADAPTATION TO HELICOPTER

Power transmission

The mechanical power supplied by the engine, is used todrive the helicopter rotors through a mechanicaltransmission.

This power drives :

- The main rotor (approximately 82 %)

- The tail rotor (approximately 10 %)

- The main gearbox (approximately 8 %).

Twin engine configuration

In a twin engine configuration, the engines are installed atthe rear of the main gearbox.

The power turbines of the two engines are mechanicallyconnected to the main gearbox which drives the rotors(main and tail rotors).

Installation requirements

The main functional requirements of the installation are :

- Constant rotor rotation speed NR in all operatingconditions

- Max torque limit C (usually imposed by the aircrafttransmission)

- Complete engine protection (N1 and N2 speeds, TETtemperature, compressor surge ∆Q/∆t…)

- Good load sharing (in the case of a multi-engineconfiguration).

Adaptation to requirements

To have a constant rotation speed of the power turbine N2,the power supplied by the engine is automatically adaptedto the demand. This adaptation is ensured by the controlsystem which meters the fuel flow injected into thecombustion chamber so as to deliver the required power(variation of the gas generator N1 rotation speed) whilekeeping the engine within its operational limits.




PRINCIPLE OF ADAPTATION TO HELICOPTER

POWER TRANSMISSION TWIN ENGINE CONFIGURATION

N2

N2

N2

t

WN1, N2, TET, Q/ t

ADAPTATION TO REQUIREMENTS

MAIN GEARBOX 8%

MAIN ROTOR82%

ENGINE100%

MAIN GEARBOX

MAIN ROTOR

TAILROTOR

ENGINE 2

ENGINE 1

time

W - Power

INSTALLATION REQUIREMENTS

Max torque C

NR(constant)

TAIL ROTOR10%



POWER PLANT2.14

MAIN CHARACTERISTICS (1)

Mass, dimensions and identification

Mass (dry)

- Engine with specific equipment and without fluid :≈ 126 kg (277 lbs) it may vary according to the engineversion.

Dimensions

- Engine :• Length : 1166 mm (45.5 inches)• Width : 465.5 mm (18.2 inches)• Height : 609 mm (23.8 inches)

Identification

- Each module has an identification plate.

- The identification plate of the complete engine is locatedon the module 1 protection tube.




MASS, DIMENSIONS AND IDENTIFICATION


465,5 mm(18.2 inches)

609

mm

(23.

8 in

ches

)

1166 mm(45.5 inches)

TURBOMECAModule référence

ARRIEL64320 BORDES - FRANCE

Brevets SZYDLOWSKI

TURBOMECA 64320 BORDES - FRANCEBrevets SZYDLOWSKI

ARRIEL

ContrôlesCertificat

Date

P kW

(dry and with specific equipment)≈ 126 kg (277 lbs)

POWER PLANT MASS



POWER PLANT2.16


Operational ratings

The operational ratings correspond to given conditions ofhelicopter operation. The ratings are generally definedunder determined speed and temperature conditions.

The following operational ratings are considered :

- AEO ratings (All Engines Operating) :• Max take-off power (T/O) : max rating which can be

used during take-off. This rating has a limited duration(5 minutes continuous)

• Max continuous power (MCP) : rating which can beused without time limitation (this does not imply thatit is used permanently)

- OEI ratings (One Engine Inoperative) :• Max contingency power (MCP) : rating which can be

used in the case of one engine failure during take-offor landing. This rating is usually limited to a periodof continuous operation : 2 minutes 30 seconds.

• Intermediate contingency power (ICP) : rating whichcan be used in the case of one engine failure in flight.This rating is usually limited to 30 minutes orunlimited

• Super contingency power (SCP or 1 min) : extremerating used in place of max. contingency on someversions. Its limited use requires particularmaintenance practices.




OPERATIONAL RATINGS


W

O.E.I. RATINGSA.E.O. RATINGS

T/O

5minutes unlimited

MAXCONTINUOUSPOWER (MCP)

MAXCONTINGENCYPOWER (MCP)

INTERCONTINGENCYPOWER (ICP)

2minutes

30seconds

SCP

1minute



POWER PLANT2.18


Factors which affect performance

The engine performance is affected by flight andatmospheric conditions. The effects of these conditionsare usually indicated by graphs which show the evolutionof performance as a function of parameters likely tomodify it (example : atmospheric temperature t0 andpressure altitude Z).

Power evolution (W)

The power delivered by the engine decreases when thealtitude (Z) and the temperature (t0) increase (this is due tothe air mass flow decrease through the engine).

The conditions of the engine installation on the aircraftshould also be noted (miscellaneous losses due toinstallation) as well as the flight conditions (essentially theaircraft speed).

Evolution of fuel consumption (CH)

The fuel consumption decreases at a given rating, when thealtitude (Z) and the temperature (t0) increase.

Evolution of specific fuel consumption (SFC)

The specific fuel consumption varies with the operatingconditions.

The specific fuel consumption decreases, when the power(W) increases (better thermal efficiency).

For this type of installation, the specific fuel consumptionwhich is mostly considered is that at the cruise rating.




FACTORS WHICH AFFECT PERFORMANCE


15 °C(59 °F)

W(kW)

t0

Z = 0 m (0 ft)Z = 6000 m (19680 ft)

- +

EVOLUTION OF POWER (W)

CH

Z = 0 m (0 ft)

Z = 6000 m (19680 ft)

EVOLUTION OFFUEL CONSUMPTION (CH)

t0

SFC(g/kW.h)

W (kW)

EVOLUTION OF SPECIFIC FUEL CONSUMPTION (SFC)

A

A = Cruise condition



POWER PLANT2.20


Engine operating envelope

The engine is designed to operate within a given climaticenvelope.

The envelope is defined by :

- The atmospheric temperature t0

- The pressure altitude Zp

- And lines of standard atmosphere.

Flight envelope

The flight envelope is illustrated by the t0/Zp diagram andthe lines of standard atmosphere, with the max tropicalzone and the min arctic zone.

Engine starting envelope

The starting and relight envelope is defined in the sameway, but it is also affected by the specifications of oil andfuel used, and sometimes by particular procedures.

Limitations

The engine operates within various limitations : rotationspeeds, temperatures, pressures…

Refer to corresponding chapters and official publications.




ENGINE OPERATING ENVELOPEMAIN CHARACTERISTICS (4)

0-500 Zp

t0

Max

ISA

Min

+15°

-50°

+50°

°C t0

Zp

Max

ISA

Min

*

-50°

+50°

°C

*

FLIGHT ENVELOPE STARTING ENVELOPE

Depending on oil and fuelspecifications. Can also requirespecial operating procedures.

ISA

Max

Min

-

-

-

International standardatmosphere

Tropical zone

Arctic zone



POWER PLANT2.22

DESIGN AND DEVELOPMENT (1)

Principles of design

The engine is designed to meet the aircraft propulsionrequirements and particularly for the new generation ofhelicopters.

The engine design is based on :

- An optimised thermodynamic cycle which gives highperformance

- Simple and reliable components giving a goodsupportability, and a good maintainability to reduce thecosts.

Engine development

The ARRIEL engine is based on research and experienceof other engines :

- First generation engines : ASTAZOU, ARTOUSTE andTURMO

Development steps

- Certification in 1977 by the French Authorities.

- The first production engine was delivered in January1978.

- ARRIEL engines will be in service far beyond 2000.

Engine designation

- Example : ARRIEL 1A2.

ARRIEL - According to TURBOMECA tradition : nameof a Pyrenean lake.

- 1 : Type

- A : Variant

- 2 : Version.





1978

ENGINE DESIGNATION

ARRIEL lake

Example : ARRIEL 1A2ARRIEL : Name of a Pyrenean lake

for the turboshaft engines1 : TypeA : Variant2 : Version

ASTAZOU500 - 1000 Shp TURMO

1500 - 1600 ShpARTOUSTE400 - 850 Shp

ENGINE DEVELOPMENT

ARRIEL 1650 - 700 Shp

Engine design

Optimisedthermodynamic cycle

Simple and reliablecomponents

SupportabilityMaintainability

Costreduction

Highperformance

STEPS

TIME

In servicefar beyond

2000

Firstproduction

1977Certification

DEVELOPMENT STEPS

PRINCIPLES OF DISIGN



POWER PLANT2.24


Application

The ARRIEL 1 is presently destined for the followinghelicopters : Squirrel and Dolphin (EUROCOPTER),A 109 K2 (Agusta), S 76 (Sikorsky), BK 117 (MBB).

Maintenance concept

The ARRIEL is designed to provide a high availability ratewith reduced maintenance costs.

The main aspects of the maintenance concept are thefollowing :

- Full modularity

- Good accessibility

- Reduced removal and installation times

- "On condition" monitoring

- High initial TBO

- Low cost of ownership :• Low production costs• Durability (TBO, defined and proven life limits)• High reliability• Low fuel consumption.

Engine fleet status

At the beginning of ..., we can note :

- Number of ARRIEL 1 engines produced : ................

- Number of ARRIEL 1 engines in operation : ...........

- Operating hours : .......................................................





-

-

-

-

-

-

CONOCO

MAINTENANCE CONCEPT

Actual modularity

Good accessibility

Reduced time of removal and installation

Condition monitoring

High initial TBO

Low cost of ownership

FLEET STATUS

- Arriel 1 engines produced

- Arriel 1 engines in service

- Operating hours

SQUIRREL(EUROCOPTER)

PT-HALB

BK 117(MBB)

A 109 K2(AGUSTA)

REGA

I-RAIE

DOLPHIN(EUROCOPTER)

G-BKXDSA 365 N

Management Aviation

S 76(SIKORSKY)



POWER PLANT2.26


ARRIEL family

The great diversity of ARRIEL 1 operation is representedin the table below including :

- Certification year

- Version

- Helicopter type

- Engine power

- Differences




Free wheel, long exhaust pipeDOLPHIN 365 C

SQUIRREL AS 350 B1977

ARRIEL 1A

ARRIEL 1B

ARRIEL FAMILY


1979

1980

1982

1983

1985

1986

1988

1991

ARRIEL 1A1

ARRIEL 1A2

ARRIEL 1C

ARRIEL 1C1

ARRIEL 1M

ARRIEL 1K

ARRIEL 1D

ARRIEL 1S

ARRIEL 1 MNARRIEL 1 D1ARRIEL 1 M1ARRIEL 1 C2

ARRIEL 1E

DOLPHIN 365 C1

DOLPHIN 365 C2

DOLPHIN 365 NDOLPHIN 365 C3

DOLPHIN 365 N1

DOLPHIN 365 F

AGUSTA A 109 K

SQUIRREL AS 350 B1/L1

SIKORSKY S 76 A

DOLPHIN 365 FSQUIRREL AS 350 B2/L2

PANTHER 365 KDOLPHIN 365 N2

BK 117

651 shp (2' 30")

640 shp (5')

667 shp (2' 30")

670 shp (2' 30")

723 shp (2' 30")

777 shp (2' 30")

723 shp (2' 30")

683 shp (5')

777 shp (2' 30")

760 shp (2' 30")

772 shp (2' 30")

700 shp (2' 30")

Adaptation to Agusta aircraftMax fuel flow limit

Free wheel, power turbine supportand exhaust pipe of the 1B

1 minute rating

Turbine materials, power turbine bearingmodified

Gas generator turbine with fir-tree mountedblades, new combustion chamber, increased N2

max N1, W and flight envelope increased

New centrifugal compressor

1S standard. Adaptation to the BK 117

Sealed turbine bladesAdaptation to Sikorsky aircraft

(support, transmission, systems...).



For training purposes only© Copyright - TURBOMECA - 2000 ENGINE

3-ENGINE- Engine ............................................................................. 3.2- Axial compressor ........................................................... 3.8- Gas generator HP section.............................................. 3.14

• Centrifugal compressor ............................................................. 3.16• Combustion chamber ................................................................. 3.22• Gas generator turbine ................................................................ 3.28

- Power turbine................................................................. 3.34- Exhaust pipe................................................................... 3.40- Reduction gearbox......................................................... 3.42- Transmission shaft and accessory gearbox ................. 3.48

• Twin-engine transmission shaft ................................................. 3.50• Single engine transmission shaft ............................................... 3.52• Accessory gearbox ...................................................................... 3.54 to 3.61




ENGINE

ENGINE - GENERAL

Function

The engine transforms the energy in the air and fuel intomechanical power on a shaft.


- Type : Free turbine with forward drive via an externalshaft

- Power class : from 480 to 560 kW (650 to 760 Shp)according to version

- Specific fuel consumption : according to version (seemaintenance manual)

- Gas generator speed (N1) : approximately 52000 RPMat 100 %

• Direction of rotation : anti-clockwise

- Power turbine speed (N2) : 41586 RPM at 100 %• Direction of rotation : clockwise

- Output shaft speed : 6000 RPM at 100 % (except the 1S1)

• Direction of rotation : clockwise

Note : Direction of rotation given viewed from the rear.

Main components

- Gas generator

• Axial compressor (module M02)• HP section (module M03)

- Centrifugal compressor- Annular combustion chamber- Two stage turbine

- Single stage power turbine (module M04)

- Exhaust pipe

- Reduction gearbox (module M05)

- Transmission shaft and accessory gearbox (moduleM01).




ENGINE - GENERAL

AXIALCOMPRESSOR

CENTRIFUGALCOMPRESSOR

COMBUSTIONCHAMBER

TURBINE POWERTURBINE

EXHAUSTPIPE

REDUCTIONGEARBOX

TRANSMISSION SHAFT ANDACCESSORY GEARBOX

Type :Free turbine

Power class :From 480 to 560 kW

(650 to 760 Shp)

Specific fuel consumption :According to version

Gas generator speed (N1) :Approximately 52000 RPM

at 100% (ACW)

Power turbine (N2) :41586 RPM at 100% (CW)

Output shaft :6000 RPM at 100%(CW) except 1S1




ENGINE

ENGINE - DESCRIPTION

Main components

- Gas generator• Axial compressor• Centrifugal compressor• Combustion chamber• Two stage turbine

- Single stage power turbine

- Exhaust pipe

- Reduction gearbox

- Transmission shaft

- Accessory gearbox.

Note : Some accessories are provided with each module.

In this manual, those components are dealt with inthe chapters corresponding to the main systems.

Modular layout

The engine comprises 5 modules :

- Module M01 : Transmission shaft and accessory gearbox

- Module M02 : Axial compressor

- Module M03 : Gas generator HP section

- Module M04 : Power turbine

- Module M05 : Reduction gearbox.

Note : A module is a sub-assembly which can be replacedon-site (2nd line maintenance) without complextooling or adaptation work.

Each module has an identification plate. The engineidentification plate is fitted on the right hand sideof the M01 protection tube.




ENGINE - DESCRIPTION

MODULE M02AXIAL COMPRESSOR

MODULE M03GAS GENERATOR

HIGH PRESSURE SECTION

MODULE M04POWER TURBINE

MODULE M05REDUCTION GEARBOX

MODULE M01TRANSMISSION SHAFT

AND ACCESSORY GEARBOX




ENGINE

ENGINE - OPERATION

The engine provides power by transforming the energy inthe air and fuel into mechanical energy on a shaft.

The process comprises compression, combustion,expansion and the transmission of the power.

Compression

The ambient air is compressed by an axial superchargingcompressor and a centrifugal compressor.

This phase is essentially characterised by the air flow(approx. 2.5 kg/s ; 5.5 lbs/sec.) and the compression ratio(approx. 8.2).

Combustion

The compressed air is admitted into the combustionchamber, mixed with the fuel and burnt in a continuousprocess.

The air is divided into two flows :

- A primary flow for combustion

- A secondary flow for cooling the gas.

This phase is essentially characterised by the temperaturerise, flame temperature approx. 2500 °C and turbine entrytemperature of approx. 1100 °C, and a pressure drop ofabout 4 %.

Expansion

- The gas expands in the gas generator turbine whichextracts the energy required to drive the compressor andaccessories (N1 rotation : 52000 RPM ACW)

During this phase the pressure and temperature of thegas drop, whilst the velocity increases.

- There is a further expansion in the power turbine whichextracts most of the remaining energy to drive the outputshaft (N2 rotation : 41586 RPM CW)

After the power turbine the gas is discharged overboardvia the exhaust pipe, giving a slight residual thrust.

Power transmission

The power is transmitted forward by a reduction gearboxand an external transmission shaft.

Note : The engine reference stations are :

0 - Air intake1 - Axial compressor inlet1' - Axial compressor outlet2 - Centrifugal compressor outlet3 - Turbine inlet4 - Gas generator turbine outlet5 - Power turbine outlet.




ENGINE - OPERATION

P kPa(PSI)

t °C(°F)

V

160(23.2)

65(149)

820(118.9)

320(608)

1125(2057) 880

(1616)

300(43.5)

600(1080)

2500(4532)

108(15.7)

800(116)

101,3(14.7)

15(59)

0 1 21' 4 53

EXHAUST

AIRINLET

COMPRESSOR

EXPANSION

POWER TRANSMISSION

(power transmitted forward by a reduction gearbox and an external shaft)

Values givenfor information at a

given reference rating

Primary air

Gas

Secondary airAIR FLOW

2.5 kg/s(5.5 lbs/s)

Residual thrust≈ 15 daN (33 lbs)

COMBUSTIONCHAMBER TURBINES

COMBUSTIONCOMPRESSION




ENGINE

AXIAL COMPRESSOR - GENERAL

Function

The axial compressor ensures a first stage of compressionto supercharge the centrifugal compressor.

Position

- At the front of the engine (the axial compressor assemblyforms the module M02).


- Type : axial transonic supercharging compressor

- Air flow : 2.5 kg/sec (5.5 lbs/sec.)

- Outlet pressure : 160 kPa (23.2 PSI)

- Outlet temperature : 65 °C (149 °F)

Main components

- Rotating components

• Air inlet cone• Axial wheel, shaft, bearing and accessory drive

shaft

- Stationary components

• Diffuser• Casing.




AXIAL COMPRESSOR - GENERAL

WHEEL DIFFUSER SHAFT

BEARING CASINGAIR INLET

CONE

Type :Axial transonic

supercharging compressor

Air flow :2.5 kg/s (5.5 lbs/sec.)

Outlet pressure :160 kPa (23.2 PSI)

Outlet temperature :65 °C (149 °F)

ACCESSORYDRIVE SHAFT




ENGINE

AXIAL COMPRESSOR - DESCRIPTION

The axial compressor module (module M02) includesrotating and stationary components.

Rotating components

The rotating assembly comprises the shaft, the inlet cone,the axial wheel and the accessory drive gear.

The inlet cone, made of light alloy, is screwed into the frontof the shaft.

The compressor wheel is fitted to the shaft. It is a disc madeof titanium alloy with blades cut from the solid.

The shaft connects the centrifugal compressor to the axialcompressor. The shaft is secured by a nut onto the tie-bolt.

This assembly is supported by two bearings : a ball bearingat the rear of the axial compressor and a ball bearing in aflexible cage at the front of the centrifugal compressor.

The accessory drive consists of a bevel gear on the shaftwhich drives a vertical drive shaft.

Stationary components

The stationary assembly includes the diffuser and thecasing.

The diffuser (diffuser-straightener) welded inside the casinghas two rows of steel stator vanes which form a divergentpassage for the air.

The casing, made of steel, houses all the compressorcomponents. It has a front flange for the mounting of theair inlet duct and a rear flange for the attachment to themodule M03. The inner hub of the casing provides thelocation for the bearings.

The casing has a boss for the mounting of the compressorbleed valve.

The module identification plate is located at the front of thecasing.




AXIAL COMPRESSOR - DESCRIPTION

INLET CONE

SHAFT

DIFFUSER

CASING

INLET CONE

SHAFT

WHEEL BEARING DIFFUSER NUT

TIE-BOLT

CASING

ACCESSORYDRIVE GEAR

WHEEL

IDENTIFICATIONPLATE




ENGINE

AXIAL COMPRESSOR - OPERATION

The axial compressor ensures a first stage of compressionin order to supercharge the centrifugal compressor.

Compressor air flow

The ambient air, admitted through the air intake duct andguided by the inlet cone, flows between the blades of theaxial compressor. The air is discharged rearwards with anincreased axial velocity.

The air then flows through the vanes of the diffuser. Dueto the divergent passage, the air velocity is reduced and thepressure increased.

The flow is straightened by the stator vanes before beingadmitted, through an annular duct, to the centrifugalcompressor.

Operating parameters

In standard conditions, the air flow is 2.5 kg/s (5.5 lbs/sec.), the outlet pressure 160 kPa (23.2 PSI) and the outlettemperature 65 °C (149 °F).

The rotation speed of the axial compressor wheel isobviously the gas generator speed.

In order to avoid compressor surge, a valve dischargesoverboard a certain amount of air in certain operatingconditions (refer to "AIR SYSTEM" chapter for furtherdetails on the compressor bleed valve).




AXIAL COMPRESSOR - OPERATION

ADMISSIONOF AMBIENT AIR

(2.5 kg/s / 5.5 lbs/sec.)

ACCELERATIONOF THE AIR

COMPRESSION ANDSTRAIGHTENING OF THE AIR

P1' : AIR DISCHARGEDTHROUGH THE COMPRESSOR

BLEED VALVE

SUPERCHARGING OF THECENTRIFUGAL COMPRESSOR

(160 kPa / 23.2 PSI ; 6 °C / 149 °F)




ENGINE

GAS GENERATOR HP SECTION

Function

The HP section of the gas generator ensures the phases ofcompression (second stage), combustion and expansion(first stage).

It provides the energy necessary to drive the power turbine.

Position

- It forms the module M03 and is mounted between themodule M02 (axial compressor) and the module M04(power turbine).


- Identification plate on the turbine casing.

For further information, refer to following pages.

Main components

- Centrifugal compressor

- Combustion chamber

- Turbine.

Note : The power turbine nozzle guide vane belongs tothe module M03.




GAS GENERATOR HP SECTION

COMBUSTIONCHAMBER

TURBINE

CENTRIFUGALCOMPRESSOR

IDENTIFICATIONPLATE




ENGINE

CENTRIFUGAL COMPRESSOR - GENERAL

Function

The compressor supplies the compressed air required forcombustion.

Supercharged by the axial compressor, it ensures thesecond stage of compression.

Position

- At the front of the module M03.


- Type : centrifugal, high efficiency

- Air flow : 2.5 kg/s (5.5 lbs/sec.)

- Compression ratio : 5.4/1 (global : 8.2/1)

- Outlet temperature : 320 °C (608 °F)

Main components

- Rotating components (wheel, shaft, bearing)

- Stationary components (diffusers, casings).




CENTRIFUGAL COMPRESSOR - GENERAL

DIFFUSERS

CENTRIFUGALWHEEL

CASINGS

BEARING

TIE-BOLT

Type :Centrifugal, high efficiency

Air flow :2.5 kg/s (5.5 lbs/sec.)

Compression ratio :5.4 / 1 (global : 8.2 / 1)

Outlet temperature :320 °C (608 °F)




ENGINE

CENTRIFUGAL COMPRESSOR -DESCRIPTION

The centrifugal compressor assembly includes rotatingand stationary components.

Rotating components

The main rotating component is the centrifugal wheel. Thewheel has blades which are cut from the solid in a disc oftitanium alloy and has a labyrinth seal on the rear shaft.

The front part of the wheel connects to the axial compressorshaft.

The rear part has a curvic-coupling for the mounting of thecentrifugal fuel injection wheel. The rotating componentsare secured by a tie-bolt.


The stationary assembly includes the diffusers and thecasings.

The compressor front cover is mounted inside the externalcasing by means of a ring of bolts which also secure theaxial compressor casing, the front cover and the diffuserassembly.

The external casing of the centrifugal compressor is boltedto the turbine casing. It is provided with several bosses forair bleeds.

The diffuser assembly comprises the first stage diffuser(radial stator vanes) and the second stage diffuser (axialstator vanes). The diffuser back-plate forms a partitionbetween the compressor and the combustion chamber.The fuel injection system is mounted on its inner hub.




CENTRIFUGAL COMPRESSOR - DESCRIPTION

WHEEL

BEARING

1st STAGEDIFFUSER

2nd STAGEDIFFUSER

EXTERNALCASING

COMPRESSORFRONT COVER

CURVICCOUPLING

FUELINJECTION

SYSTEM

LABYRINTHSEAL

TIE-BOLT

DIFFUSERASSEMBLY

COMPRESSORFRONT COVER

WHEEL

EXTERNAL CASING




ENGINE

CENTRIFUGAL COMPRESSOR -OPERATION

The centrifugal compressor ensures the main stage ofcompression.

Compressor air flow

The air supplied by the axial compressor flows betweenthe blades of the centrifugal compressor. The air pressureincreases due to the divergent passage between the bladesand the air velocity increases due to the centrifugal flow.

The air leaves the tips of the blades at very high velocityand then flows through the first stage diffuser vanes wherethe velocity is decreased and the pressure is increased.

The air then passes through an elbow and the flow becomesaxial. In the second stage diffuser, the velocity is againdecreased and the pressure increased. The air is thenadmitted into the combustion chamber.


In standard conditions, the air flow is 2.5 kg/s (5.5 lbs/sec.), the compression ratio 5.4 (total 8.2), the outletpressure 820 kPa (118.9 PSI) and the outlet temperature320 °C (608 °F).

The compressor wheel rotation speed is obviously the gasgenerator speed.




CENTRIFUGAL COMPRESSOR - OPERATION

AIR ADMITTED INTOTHE COMBUSTION

CHAMBER(820 kPa / 118.9 PSI ;

320 °C / 608 °F)

ACCELERATION ANDCOMPRESSION OF THE AIR

SUPERCHARGING BYTHE AXIAL COMPRESSOR

(2.5 kg/s / 5.5 lbs/sec. ;160 kPa / 23.2 PSI)

COMPRESSION OF THE AIRIN THE DIFFUSERS




ENGINE

COMBUSTION CHAMBER - GENERAL

Function

The combustion chamber forms an enclosure in which theair-fuel mixture is burnt.

Position

- Central section of the gas generator.


- Type : annular with centrifugal fuel injection

- Overall fuel-air ratio : 1/45

- Turbine inlet temperature : 1125 °C (2057 °F).

Main components

- Outer part (front swirl plate and mixer unit)

- Inner part (rear swirl plate and shroud)

- Fuel injection system

- Turbine casing.




COMBUSTION CHAMBER - GENERAL

Type :Annular with centrifugal

fuel injection

Overall fuel-air ratio :1/45

Turbine inlet temperature :1125 °C (2057 °F)

OUTER PART

Front swirlplate

Mixer unit

INNER PART

Rear swirlplate

Shroud

FUEL INJECTIONSYSTEM

TURBINECASING




ENGINE

COMBUSTION CHAMBER - DESCRIPTION

The combustion chamber assembly includes the outerpart, the inner part, the turbine casing and the fuel injectionsystem.

Outer part

The outer part includes the front swirl plate and the mixerunit. The front swirl plate is provided with calibratedorifices for the passage of primary air ; it is secured to themixer unit with special rivets.

The mixer unit is provided with calibrated orifices for thepassage of dilution air ; it is bolted to the rear flange of theturbine casing. It includes the dilution tubes.

Inner part

The inner part includes the rear swirl plate and the shroud.

The rear swirl plate is provided with calibrated orifices forthe passage of primary air.

The shroud, integral with the rear swirl plate surrounds theshaft ; it is bolted to the turbine nozzle guide vane.

Note : The two parts are made of special alloy. Thecalibrated orifices are drilled using the electronbeam process.

Turbine casing

The casing houses the combustion chamber and the turbine.It has various bosses and, particularly the boss for thecombustion chamber drain valve at the bottom of thecasing.

Fuel injection system

The main fuel injection system includes : the fuel inletunion, the inner fuel tube, the fuel distributor and thecentrifugal injection wheel.

The injection wheel is mounted by means of curviccouplings between the compressor and the turbine shaft(refer to "FUEL SYSTEM" chapter for further details onthe fuel injection system).




COMBUSTION CHAMBER - DESCRIPTION

FRONT SWIRLPLATE

DILUTION TUBEMIXER UNIT

TURBINE CASING

SHROUD

MIXER UNIT

INJECTION WHEEL

REAR SWIRLPLATE

Drain valve

FUEL INJECTIONSYSTEM

TURBINE CASING

FRONT SWIRLPLATE

REAR SWIRLPLATE

SHROUD

Curvic-coupling




ENGINE

COMBUSTION CHAMBER - OPERATION

The combustion chamber forms an enclosure in which thefuel - air mixture is burnt.

Combustion chamber flow

In the combustion chamber, the compressed air is dividedinto two flows : a primary air flow mixed with the fuel forcombustion and a secondary air flow (or dilution air flow)for cooling of the burnt gases.

Primary air

One part flows through the orifices of the front swirl plate.

A second part flows through the hollow vanes of theturbine nozzle guide vane (cooling of the vanes) andthrough the orifices of the rear swirl plate.

The primary air is mixed with the fuel sprayed by theinjection wheel. The combustion occurs between the twoswirl plates. The flame temperature reaches approximately2500 °C (4532 °F).

Secondary air

The secondary air (or dilution air) flows through theorifices of the mixer unit and the dilution tubes. It iscalibrated to obtain flame stability, cooling of the burntgases, and distribution of temperature on the turbine.

Gas

The gas produced by the combustion is directed into theturbine nozzle guide vane.


The fuel-air ratio for combustion is approximately 1/15 ;the total ratio is approximately 1/45.

The pressure drop in the combustion chamber isapproximately 4 %.

The turbine inlet temperature (at design point) isapproximately 1125 °C (2057 °F).




COMBUSTION CHAMBER - OPERATION

FUEL INJECTION COMBUSTION(2500 °C / 4532 °F)(pressure loss : 4 %)

GAS FLOW TO THETURBINE

(1125 °C / 2057 °F)

Primary air (combustion)

Secondary air (cooling of burnt gases)

Burnt gases

COMPRESSED AIR(820 kPa / 118.9 PSI ; 320 °C / 608 °F)




ENGINE

GAS GENERATOR TURBINE - GENERAL

Function

The turbine extracts sufficient energy from the gas flow todrive the compressors and the accessories.

Position

- At the rear of the gas generator.


- Type : two stage axial

- Turbine inlet temperature : 1125 °C (2057 °F)

- Turbine outlet temperature : 880 °C (1616 °F)

- N1 speed ≈ 52000 RPM (100 %) ACW

Main components

- Rotating components (wheels, shafts, bearing)

- Stationary components (nozzle guide vanes, containmentshield, casing).




GAS GENERATOR TURBINE - GENERAL

Type :Two stage axial


Turbine outlet temperature :880 °C (1616 °F)

N1 speed 52000 RPM (100%) ACW

NOZZLE GUIDEVANES

WHEELS

BEARING

CONTAINMENTSHIELD

SHAFTSCASING




ENGINE

GAS GENERATOR TURBINE -DESCRIPTION

The gas generator turbine assembly includes rotatingcomponents and stationary components.

Rotating components

The main rotating components are the turbine wheels.

The wheels consist of either a disc and fir-tree mountedblades or blades cut from the solid.

The front wheel is coupled by curvic-couplings to theturbine shaft and to the second stage wheel. The rear wheelis coupled to a stub shaft by a curvic-coupling.

The stub shaft is supported by a roller bearing. Rotatinglabyrinths provide sealing.

A tie-bolt secures the rotating assembly.


The stationary components are the turbine nozzle guidevanes, the containment shield, the turbine casing and thediffuser casing.

The first stage nozzle guide vane includes a row of hollowvanes. It is mounted on the combustion chamber.

The second stage nozzle guide vane includes a row ofvanes mounted in a ring.

The containment shield provides containment in case ofblade failure.

The turbine casing forms the housing of turbines andcombustion chamber.

The diffuser casing connects the gas generator and thepower turbine and its hub contains the housing for the gasgenerator rear bearing. At the rear it houses the powerturbine nozzle guide vane.




GAS GENERATOR TURBINE - DESCRIPTION

NOZZLE GUIDEVANES

TURBINESHROUD

TURBINEWHEELS

BEARING(roller)

TIE-BOLT

REARSHAFT

Curvic-couplingCONTAINMENTSHIELD

TURBINECASING

FRONTSHAFT

DIFFUSERCASING

TURBINESHROUD

TURBINECONTAINMENT

SHIELD

FRONTSHAFT

DIFFUSERCASING

1st STAGETURBINEWHEEL

2nd STAGETURBINEWHEEL

1st STAGENOZZLE GUIDE

VANE

2nd STAGENOZZLE GUIDE

VANE




ENGINE

GAS GENERATOR TURBINE - OPERATION

The gas generator turbine transforms the gas energy intomechanical power to drive the compressors and variousaccessories.

The operation is characterized by the first phase ofexpansion.

Turbine gas flow

The burnt gases first flow through the nozzle guide vanes.The gas velocity increases due to the convergent passage.

The flow on the blades results in aerodynamic forceswhose resultant causes the rotation of the wheel.

The gases, still containing energy, are directed to thepower turbine.


The operation is characterised by the following parameters :






GAS GENERATOR TURBINE - OPERATION

GAS TO THEPOWER TURBINE(880 °C / 1616 °F)

ROTATIONCOMPRESSOR DRIVE

(52000 RPM ; ACW800 kW ; 1072 Shp)

GAS FROM THE COMBUSTIONCHAMBER

(1125 °C / 2057 °F)

GAS EXPANSION IN THE NOZZLE GUIDE VANE(convergent passage)

Nozzleguide vane

Turbinewheel

Rotation




ENGINE

POWER TURBINE - GENERAL

Function

The turbine extracts the energy from the gas to drive thepower shaft through the reduction gearbox.

Position

- Between the gas generator and the reduction gearbox.

It forms the module M04.


- Type : axial, single-stage



- N2 speed at 100 % ≈ 41586 RPM, CW

Main components

- Rotating components (wheel, shaft, bearings)

- Stationary components (nozzle guide vane, containmentshield, casing).




POWER TURBINE - GENERAL

NOZZLE GUIDE VANE WHEEL BEARINGS

SHAFTPOWER TURBINECASING

CONTAINMENT SHIELD

Type :Axial, single stage


Turbine outlet temperature :600 °C (1080 °F)

N2 speed at 100% ≈ 41586 RPM (CW)




ENGINE

POWER TURBINE - DESCRIPTION

The power turbine assembly forms the module M04. Itincludes rotating components and stationary components.

Rotating components

The main rotating component is the power turbine with itsshaft.

The wheel includes a disc (integral with the shaft) and fir-tree mounted blades.

The shaft is supported by two bearings : a front rollerbearing and two rear ball bearings. It is fitted with twophonic wheels

The front bearing sealing is ensured by a pressurisedlabyrinth seal (pressurisation with compressor air directedto the power turbine through an external pipe and innerducts).

The power is transmitted to the reduction gear by a muffcoupling.


The main stationary components are the turbine nozzleguide vane, the power turbine casing and the bearinghousing.

The nozzle guide vane includes a row of hollow vanes. It ispart of the module M03.

The power turbine casing engages over the gas generatoroutlet diffuser and is bolted to the module M03. It comprisesan outer casing and an inner hub supported by three struts.

The bearing housing is installed in the inner hub of thecasing. Its rear part engages in the reduction gearbox.

The identification plate is located on the power turbinecasing.

A containment shield is fitted around the rear of the casing.




POWER TURBINE - DESCRIPTION

FRONTBEARING

REARBEARING

SHAFT

Muff coupling

BEARINGHOUSING

PHONICWHEELS

WHEEL CONTAINMENTSHIELD

NOZZLE GUIDEVANE

POWER TURBINECASING

PRESSURISEDLABYRINTH

SEAL Identification plate

BEARINGHOUSING

PHONIC WHEELS

WHEEL

LABYRINTH

POWER TURBINECASING




ENGINE

POWER TURBINE - OPERATION

The power turbine transforms the gas energy intomechanical power to drive the reduction gearbox.

The operation is characterised by the second phase ofexpansion.

Turbine flow

The gas supplied by the gas generator flows through thenozzle guide vane. In the nozzle guide vane, the gasvelocity increases due to the convergent passage.

The gases are directed onto the turbine wheel and theresultant of the aerodynamic forces on the blades causesthe wheel to rotate. The gases are then expelled overboardthrough the exhaust pipe.


The operation is characterised by the following parameters :

- Rotation : CW


- Power extracted : depending on the version




POWER TURBINE - OPERATION

GAS FROM THEGAS GENERATOR

TURBINE(880 °C / 1616 °F)

Nozzleguide vane

Turbinewheel

GAS EXHAUST

REDUCTION GEARBOXDRIVE (CW)

ROTATION OF THEPOWER TURBINE

EXPANSION IN THENOZZLE GUIDE VANE

Rotation




ENGINE

EXHAUST PIPE

Function

The exhaust pipe continues the expansion phase andexpels the gas overboard.

Position

- Behind the power turbine, around the reduction gear.


- Type : Elliptical

- Non-modular part

- Gas temperature : 600 °C (1080 °F)

- Residual thrust : ≈ 15 daN (33 lbs).

Main components

- Exhaust pipe

- Heat shield.

Note : The exhaust pipe is considered to be an SRU.

Description

The exhaust pipe, which has an elliptical outlet, is madefrom stainless steel. It is bolted to the rear flange of thepower turbine casing with the containment shield.

A heat shield is fitted between the exhaust pipe and thereduction gearbox to protect the gearbox from the exhaustheat.

The exhaust pipe has a drain at the bottom.

Operation

Functionally it should be noted that the exhaust gas stillcontains a certain amount of energy which produces asmall residual thrust of about 15 daN (33 lbs).




EXHAUST PIPE

GAS FROMPOWER TURBINE

RESIDUAL THRUST(15 daN / 33 lbs)

EXHAUST PIPE

HEAT SHIELD

DESCRIPTION OPERATION

GAS EXHAUST(600 °C ; 1080 °F)

DRAINREDUCTIONGEARBOX




ENGINE

REDUCTION GEARBOX - GENERAL

Function

The reduction gearbox provides a reduced speed outputand transmits the drive forwards.

Position

- At the rear of the engine

- It forms the module M05.


- Type : 3 stages, helical gears

- Output gear speed : 6000 RPM at 100 %.

Main components

- Drive gear

- Intermediate gear

- Output gear

- Casings

- Hydraulic torquemeter.




REDUCTION GEARBOX - GENERAL

Type :3 stages, helical gears

Output gear speed :6000 RPM at 100%

OUTPUTGEAR

DRIVEGEAR

INTERMEDIATEGEAR

CASINGS

HYDRAULICTORQUEMETER

MUFFCOUPLING




ENGINE

REDUCTION GEARBOX - DESCRIPTION

The reduction gearbox module mainly includes threegears contained in two half casings.

Drive gear

The drive gear is linked to the power turbine by a muffcoupling. It is supported by two roller bearings.

Intermediate gear

It is a double helical type gear : one gear meshes with thedrive gear, the other one with the output gear. Thetorquemeter piston is fitted in its hub. The intermediategear is supported by two roller bearings.

Output gear

It is supported by a ball bearing at the front and a rollerbearing at the rear.

The hub is internally splined to receive the transmissionshaft.

Reduction gearbox casing

The gears are housed in a light alloy gearbox formed bytwo half casings. A fork shaped steel plate is mounted onthe front face of the casing to prevent rearward movementof the power turbine in the event of overspeed.

The module identification plate is located at the bottom ofthe casing.




REDUCTION GEARBOX - DESCRIPTION

DRIVE GEAR

INTERMEDIATEGEAR

FRONTCASING

IDENTIFICATIONPLATE

FORK SHAPEDPLATE

OUTPUTGEAR

REARCASING

INTERMEDIATE GEARDRIVE GEAR

OUTPUTGEAR

Muff coupling

TORQUEMETERPISTON




ENGINE

REDUCTION GEARBOX - OPERATION

The reduction gear provides a forward output drive at areduced speed.

Operation of the reduction gear

The drive gear is directly driven by the power turbine shaft(muff coupling drive). It transmits the movement to theintermediate gear which contains the hydraulic torquemeter.

The intermediate gear drives the output gear which providesthe power drive at a speed of approximately 6000 RPM,clockwise.




REDUCTION GEARBOX - OPERATION

TORQUEMETERPISTON

DRIVE GEARDRIVEN BY

THE POWER TURBINE

DOUBLEINTERMEDIATE GEAR

OUTPUTGEAR

TRANSMISSIONSHAFT




ENGINE

TRANSMISSION SHAFT AND ACCESSORYGEARBOX

Function

The shaft transmits the power to the helicopter via thepower off-take at the front of the engine.

The accessory gearbox provides the drive for the engineaccessories.

Position

- Shaft beneath the engine

- Accessory gearbox at the front of the engine

- This assembly forms the module M01.




TRANSMISSION SHAFT AND ACCESSORY GEARBOX

ACCESSORY DRIVE SHAFT

TRANSMISSIONSHAFTCASINGS

POWER OFF-TAKE




ENGINE

POWER TRANSMISSION SHAFT -TWIN-ENGINE CONFIGURATION - GENERAL - DESCRIPTION

Function

The shaft transmits the power to the front power off-take.

Position :

- Lower part of the engine.


Hollow steel shaft.

Main components


- Protection tube

- Accessory drive gear

- Power off-take.

Description

The shaft transmits the power to the power off-take andaccessory gearbox. The shaft is located in a protection tubebolted to the reduction gearbox at the rear and to theaccessory gearbox at the front.

The front of the shaft is supported by a ball bearing in theaccessory gearbox front casing. The triangular flangewhich forms the power off-take is splined onto the front ofthe transmission shaft and is secured by a nut. Sealing ofthe oil which lubricates the bearing is ensured by a carbonseal.

Three oil tubes are located between the shaft and theprotection tube.

The rear of the shaft is splined into the hub of the outputgear of the reduction gear.




POWER TRANSMISSION SHAFT - TWIN-ENGINE CONFIGURATIONGENERAL - DESCRIPTION

OUTPUTGEAR

SHAFT

ACCESSORYDRIVE GEAR

OIL TUBE

POWER OFF-TAKE(triangular flange)

BEARING

CARBONSEAL

PROTECTIONTUBE

BEARING




ENGINE

POWER TRANSMISSION SHAFT -SINGLE ENGINE CONFIGURATION -GENERAL - DESCRIPTION

Function

The shaft transmits the power to the front and to the rear ofthe engine.

Position :

- Lower part of the engine.


- Hollow steel shaft with coaxial drive shaft.

Main components


- Protection tube

- Accessory drive gear

- Drive shaft

- Free wheel.

Description

The shaft transmits the power to the power drive shaft. Thetransmission shaft is located in a protection tube bolted tothe reduction gearbox at the rear and to the accessorygearbox at the front.

The front of the transmission shaft is supported by a ballbearing in the accessory gearbox front casing. A triangularflange is splined onto the front of the transmission shaft.Sealing of the oil which lubricates the bearing is ensuredby a carbon seal.

Three oil pipes are located within the protection tube.

A free wheel is mounted on the triangular flange to drivethe power drive shaft which drives the main gearbox andthe tail rotor.

Lubrication of the free wheel and its bearing is by the oilcontained in the free wheel housing, or by the oil systemof the engine, according to the version.

The rear of the transmission shaft is splined into the hub ofthe output gear of the reduction gear.

The rear of the tail rotor drive shaft is supported by a ballbearing in the hub of the output gear. A carbon seal is fittedin the rear cover of the gearbox.




POWER TRANSMISSION SHAFT - SINGLE ENGINE CONFIGURATIONGENERAL - DESCRIPTION

TAIL ROTORDRIVE

BEARINGBEARINGSEAL TRIANGULAR FLANGE

POWER DRIVESHAFT

FREE WHEEL

SHAFT

CARBONSEAL

FRONT PART REAR PART

ACCESSORYDRIVE GEAR

CARBON SEAL OIL TUBE




ENGINE

ACCESSORY GEARBOX - GENERAL

Function

To provide the drive for the engine accessories.

Position

- At the front of the engine.


- Type of gears :• spur gear• bevel gear.

Main components

- Accessory drive shaft

- Accessory drive train

- Casings.




ACCESSORY GEARBOX - GENERAL

Type of gears :Spur gearBevel gear

ACCESSORYDRIVE SHAFT

(N1)

ACCESSORYDRIVE TRAIN

FRONTCASING

REARCASING

ACCESSORYDRIVE GEAR

(N2)




ENGINE

ACCESSORY GEARBOX -DESCRIPTION (1)

The accessory gearbox has four drives on the front face :• starter generator• fuel control unit N1• fuel control unit N2• main power shaft.

and four mounting bolts on the upper part for attachmentof the M02.

It has 3 power drives on the rear face :• oil pump• N1 tachometer generator• N2 tachometer generator.

and the protection tube mounting flange, and the accessorydrive shaft passage on the upper part.




ACCESSORY GEARBOX - DESCRIPTION (1)

REAR VIEWFRONT VIEW

ACCESSORYDRIVE SHAFTPASSAGE (N1)

OILPUMP

N2TACHOMETERGENERATOR

N1TACHOMETERGENERATOR

PROTECTIONTUBE MOUNTING

FLANGE

STARTERGENERATOR

DRIVE

POWERDRIVE

FUEL CONTROLUNIT N2 DRIVE

FUEL CONTROLUNIT N1 DRIVE

MOUNTINGBOLTS (4)




ENGINE

ACCESSORY GEARBOX -DESCRIPTION (2)

The transmission shaft and the accessory box assemblyconstitutes the module M01 located at the engine lowerpart.

The accessory gearbox includes a train of gears housed ina gearbox formed by two half casings made of light alloy.The gearbox is installed at the bottom of the axialcompressor by means of four bolts.

The starter-generator gear forms the engine breather.

The fuel control unit N1 gear drives the oil pump at therear.

The fuel control unit N2 gear is driven by the gear on thetransmission shaft.

The engine front support casing is bolted onto the frontface of the accessory gearbox.

The module identification plate is fitted on the front faceof the gearbox.




ACCESSORY GEARBOX - DESCRIPTION (2)

BREATHER GEAR

TRANSMISSIONSHAFT GEAR

(N2)

FRONT CASING

STARTERGENERATOR DRIVE

Identificationplate

FRONT SUPPORTCASING

N2 FUELCONTROL UNIT

N1 FUEL CONTROL UNITAND OIL PUMP DRIVE

REAR CASING

DRIVE SHAFT(N1)




ENGINE

ACCESSORY GEARBOX - OPERATION

The operation is considered during engine starting and innormal running.

Operation during engine starting

During starting, the starter motor drives the accessorygearbox and thus the gas generator rotating assembly.

The compressors supply air to the combustion chamberand the starting sequence continues.

At self-sustaining speed (approximately 45 % N1) theelectrical supply to the starter motor is cut. The startermotor is then mechanically driven by the engine andoperates as a generator to provide DC current to the aircraftelectrical system.

Operation in normal running

The gas generator drives the accessory gear train throughthe bevel gear located on the axial compressor shaft.

The following accessories are driven :

- Starter-generator

- FCU : N1 and N2

- Oil pumps

- Tachometer generator : N1 and N2.




ACCESSORY GEARBOX - OPERATION

OPERATION DURINGENGINE STARTING

OPERATION IN NORMAL RUNNING (N1 50 %)

STARTERMOTOR

FWD FWD

DRIVESHAFT

DIRECT CURRENTGENERATOR

DRIVESHAFT



For training purposes only© Copyright - TURBOMECA - 2000 OIL SYSTEM

4-OIL SYSTEM- Oil system ...................................................................... 4.2- Lubrication .................................................................... 4.8- Oil tank .......................................................................... 4.12- Oil pumps ...................................................................... 4.14- Electrical magnetic plugs .............................................. 4.20- Oil filter ......................................................................... 4.24- Filter pre-blockage indicator ........................................ 4.30- Oil cooler ....................................................................... 4.34- Centrifugal breather ..................................................... 4.36- Magnetic plugs ............................................................... 4.40- Strainers ........................................................................ 4.42- Indicating devices .......................................................... 4.44- Oil pipes and ducts ........................................................ 4.50 to 4.51




OIL SYSTEM

OIL SYSTEM - GENERAL

Function

The oil system ensures lubrication and cooling of theengine.

Position

All the components are fitted on the engine except the tankand cooler.


- System type : variable pressure, full flow, dry sump,synthetic oil

- Max oil temperature : 115 °C (239 °F)

- Min oil pressure : 90 or 130 kPa (13 or 18.85 PSIG)according to version

- Max oil pressure : 800 kPa (116 PSIG)

- Oil pressure : ≈ 300 kPa (43.5 PSIG)

- Max oil consumption : 0.3 l/h or 0.15 l/h according toversion.

Lubrication requirements

Lubrication is required for the following components :

- Gas generator front bearings• Axial compressor bearing• Centrifugal compressor bearing• Accessory drive bearing

- Gas generator rear bearing

- Power turbine bearings

- Reduction gearbox

- Accessory drive gearbox.




OIL SYSTEM - GENERAL

REDUCTION GEARBOX

Type :Variable pressure, full flow,

dry sump, synthetic oil

Max temperature :115 °C (239 °F)

Min pressure :90 or 130 kPa

(13 or 18.85 PSIG)according to version

Max pressure :800 kPa (116 PSIG)

Max consumption :0.3 l/h or 0.15 l/h

according to version

Engine lubricationand cooling

FRONTBEARINGS

REARBEARING

REARBEARINGS

FRONTBEARING

POWER TURBINEGAS GENERATOR

BEARINGS GEARS

ACCESSORY DRIVE GEARBOX

BEARINGS GEARS

OIL SYSTEM




OIL SYSTEM

OIL SYSTEM - DESCRIPTION

The system contains all the components necessary forengine lubrication : tank, pumps, filter, strainers, cooler,breather and indicating devices.

Oil tank

The tank contains the volume of oil required to lubricatethe engine. It is supplied by the aircraft manufacturer.

Oil pumps

The pump pack contains one pressure pump and threescavenge pumps. The gear type pumps are driven by theaccessory gearbox. The pressure pump is equipped with apressure relief valve and in some versions a check valve.

Oil filter

The filter retains any particles which may be present in theoil. It is provided with a by-pass valve and a pre-blockageindicator.

Strainers

The strainers protect the scavenge pumps from debris inthe system.

Cooler

The oil cooler cools the oil. It is supplied by the aircraftmanufacturer.

Breather

The centrifugal breather separates the oil from the air/oilmist and vents the system.

Indicating devices

- Oil temperature probe (aircraft manufacturer supply)

- Pre-blockage indicator

- Low oil pressure switch

- Pressure transmitter

- Magnetic plugs

- Electrical magnetic plugs.




OIL SYSTEM - DESCRIPTION

OIL PUMPS

Scavengepumps

Pressurepump

Electricalmagnetic plug

Pre-blockageindicator

CENTRIFUGALBREATHER

COOLER

Checkvalve

Oil temperature

probe

FILTER

TANK

By-passvalve

PressureReliefvalve

Check valve(some versions)


ENGINEAIRFRAME

Magneticplug

STRAINERS

Low oilpressure switch

Pressuretransmitter

Magneticplug




OIL SYSTEM

OIL SYSTEM - OPERATION

The main functions of the oil system are : supply, scavenge,breathing and indicating.

Supply

The pressure pump draws the oil from the tank andsupplies the system. A pressure relief valve limits maximumpressure by returning oil to the pump inlet.

The oil is then delivered through a check valve, the oilfilter and a calibrated orifice to the engine sections whichrequire lubrication :

- Gas generator front bearings

- Gas generator rear bearing

- Power turbine bearings

- Reduction gearbox

- Accessory gearbox and torquemeter (supply upstreamof the calibrated orifice).

The oil is sprayed by jets onto the parts to be lubricated.

Scavenge

After lubrication, the oil falls by gravity to the bottom ofthe sumps. The oil is then immediately drawn away by thescavenge pumps and returned to the tank through the oilcooler (dry sump system).

The strainers protect the scavenge pumps against anyparticles which may be held in the oil.

Breathing

The oil mist which results from lubrication is returned tothe accessory gearbox, where the oil is separated from theair by a centrifugal breather which vents overboard.

The gas generator rear bearing has a direct air vent.

Indicating

The system ensures the following indications : pressure,temperature, low pressure, electrical magnetic plug andfilter pre-blockage.




OIL SYSTEM - OPERATION

PRESSUREPUMP

CENTRIFUGALBREATHER

ENGINEAIRFRAME

Temperatureprobe FILTER

Low oilpressure switch

Pressuretransmitter

SCAVENGEPUMPS

COOLER



TANK

Calibratedorifice

Checkvalve

Checkvalve Magnetic

plugMagnetic

plug

SUPPLY SCAVENGE BREATHING AIR VENT

STRAINERS




OIL SYSTEM

LUBRICATION (1)

This section describes the lubrication of the engine parts :gas generator, power turbine, reduction gear and accessorydrive train.

Gas generator front bearings

Supply. The oil is taken by external pipe to the upper partof the axial compressor casing. It is supplied to a jet whichsprays the oil onto the two compressor bearings and theaccessory drive bevel gear.

The bearing housing is sealed by labyrinth seals.

Scavenge. The oil falls by gravity into the accessorygearbox from where it is drawn by a scavenge pump andreturned to the tank.

Breathing. The air/oil mist which results from lubricationpasses into the accessory gearbox and is vented throughthe centrifugal breather.

Gas generator rear bearing

Supply. The oil, taken by external pipe, passes through arestrictor and a tube screwed into the bearing housing andis sprayed onto the bearing.

The bearing housing is sealed by pressurised labyrinthseals.

Scavenge. The oil falls by gravity to the bottom of thehousing, through a tube in the bottom of the housing andis returned to the tank by a scavenge pump.

Breathing. The air/oil mist which results from lubricationpasses out through a tube screwed into the top of thehousing and is vented overboard.

Accessory gearbox

Supply. The oil is supplied by an internal duct. It passesthrough ducts and jets to the accessory gearbox gears andbearings.

Scavenge. The oil falls by gravity to the bottom of thegearbox casing. It is immediately drawn by the scavengepump and returned to the tank via the oil cooler.

Breathing. The oil/air vapours resulting from thelubrication pass to the centrifugal breather. Then, the de-oiled vapours are vented overboard.

Torquemeter pressure

Supply. The torque indicating system receives a supply ofoil from the pump outlet via a restrictor and through a tubein the protection tube. This system is described in chapter 8.




LUBRICATION (1)

AXIAL COMPRESSORBEARING

CENTRIFUGAL COMPRESSORBEARING

DIRECTAIR VENT

GAS GENERATORREAR BEARING

TORQUEMETERPRESSURE

SCAVENGE

ACCESSORYGEARBOX

AIR VENT

Supply Torquemeter pressure Scavenge Air vent




OIL SYSTEM

LUBRICATION (2)

Power turbine bearings and reduction gearbox

Supply. The oil is supplied via a tube located inside thetransmission shaft protection tube. The bearings and gearsare lubricated by jets via internal drillings in the casings.

A labyrinth seal is fitted in front of the power turbine frontbearing to seal the housing.

Scavenge. The oil which has lubricated the power turbinebearings is returned to the reduction gearbox. The oil in thereduction gearbox falls to the bottom of the casing and isdrawn by a scavenge pump, through a tube in thetransmission shaft protection tube, and is returned to thetank.

Breathing. The air/oil mist resulting from lubrication passesthrough the protection tube, into the accessory gearboxwhere it passes through the centrifugal breather.

Torquemeter

A tube in the protecting tube, connects the torque transmitterto the torquemeter piston in the intermediate gear of thereduction gearbox.




LUBRICATION (2)

POWER TURBINEBEARINGS

LUBRICATION OFTHE REDUCTION GEARBOX(gears and bearings)TORQUEMETER

SUPPLY

BREATHING

SCAVENGESupply

Breathing

Torquemeter pressure

Scavenge




OIL SYSTEM

OIL TANK

Function

The tank contains the oil required for engine lubrication.

Position

- On the aircraft : it is installed with the oil cooler abovethe plenum chamber, between the main gearbox and thefront firewall.


- Aircraft manufacturer supply

- Max capacity : 6 litres (1.56 US G)

Main components

- Filler cap

- Level indicator

- Drain plug (with magnetic plug)

- Temperature probe

- Unions (supply, return and vent).

Note : Refer to the aircraft manual for the descriptionand operation.




OIL TANK

Air vent

LEVEL INDICATOR

Engine oil supply

TEMPERATURE PROBE

Tank drain

Oil return(from engine)

FILLER CAP(provided with a dip stick)

OIL COOLER

Aircraft supply

Max capacity :6 litres (1.56 US G)

DRAIN PLUG(with magnetic plug)




OIL SYSTEM

OIL PUMPS - GENERAL

Function

The pumps ensure oil circulation.

Position

- On the engine : the pump pack is mounted on the rearface of the accessory gearbox.


- Gear type

- Pressure pump outlet pressure : ≈ 300 kPa (43.5 PSI)(variable pressure system)

- Pressure relief valve setting : 800 kPa (116 PSI)

- Check valve : according to version.

Main components

- Drive shaft

- Pump body (with one pressure pump, three scavengepumps and valves).




OIL PUMPS - GENERAL

Type :Gear

Pressure pumpoutlet pressure :

≈ 300 kPa (43.5 PSI)(variable pressure system)

Pressure relief valve setting :800 kPa (116 PSI)

Check valve :According to version

DRIVE SHAFT PUMP BODY

PACK OF PUMPS

- Gas generator rear bearing scavenge pump- Reduction gearbox scavenge pump- Accessory gearbox scavenge pump- Pressure pump




OIL SYSTEM

OIL PUMPS - DESCRIPTION

The oil pump pack is mounted on the rear left face of theaccessory gearbox and is driven at a speed proportional toN1.

It consists of :

- 4 gear type pumps :• Pressure pump• Gas generator rear bearing scavenge pump• Reduction gearbox scavenge pump• Accessory gearbox scavenge pump

- The pump casing provided with inlet and outlet orifices

- The pressure relief valve

- The check valve (according to version).




OIL PUMPS - DESCRIPTION

PUMP BODY

PUMP BODY

PRESSUREPUMP

ACCESSORY GEARBOXSCAVENGE PUMP

CHECKVALVE

DRIVE SHAFT

REDUCTION GEARBOXSCAVENGE PUMP

GAS GENERATOR REARBEARING SCAVENGE PUMP

PRESSURERELIEF VALVE




OIL SYSTEM

OIL PUMPS - OPERATION

General

The pressure pump draws the oil from the tank and pumpsit to the filter.

The scavenge pumps draw the oil from the casings andpump it to the cooler.

Pressure relief valve operation

If the oil pressure exceeds the valve setting the valve opensand allows the oil to return to the pump inlet.

In normal operation the valve is closed and only opens inexceptional circumstances, e.g. starting with very lowtemperature.

Pressure pump outlet check valve operation

When the oil pressure is very low, e.g. engine stopped orat the beginning of start, the valve is closed in order toprevent flow between the pump and system.




OIL PUMPS - OPERATION

Suction - Overpressure

Scavenge

PressureOPERATION OF THE CHECK VALVE

OPERATION OF THE PRESSURE RELIEF VALVE

Normalrunning condition

(valve closed)

Overpressure(valve open)

Normalrunning condition

(valve open)

Engine stoppedand initial phase

of starting(valve closed)

PRESSUREPUMP

ACCESSORY GEARBOXSCAVENGE PUMP

REDUCTION GEARBOXSCAVENGE PUMP

GAS GENERATOR REARBEARING SCAVENGE PUMP





OIL SYSTEM

ELECTRICAL MAGNETIC PLUGS -GENERAL

Function

The electrical magnetic plugs provide a cockpit indicationof metal particles in the oil system.

Position

- In the system :• one downstream of the scavenge pumps• one upstream of the rear bearing scavenge pump

- On the engine :• one near the pump assembly (scavenge pumps)• one on the left side of the accessory gearbox (rear

bearing).


- Type :• Magnetic with electrical indication• Self-sealing housing.

Main components

- Magnetic plug body

- Electrical connector

- Housing (strainer).

Note : The oil system also has two mechanical magneticplugs located on the lower part of the accessorygearbox and on the lower part of the reductiongearbox.




ELECTRICAL MAGNETIC PLUGS - GENERAL

Type :Electrical

magnetic plug

HOUSING

MAGNETIC PLUGBODY

ELECTRICALCONNECTOR

Housing :Self-sealing




OIL SYSTEM

ELECTRICAL MAGNETIC PLUGS -DESCRIPTION - OPERATION

Description

The electrical magnetic plugs comprise a magnetic probewhich has two parts which are electrically insulated fromone another and have a small gap between them.

A resistor is connected across the gap. The plugs areconnected, via the engine electrical harness, to the aircraftinstrument panel with an optional test system.

The plugs are fitted into a housing which is provided witha self-sealing valve.

The scavenge oil flows across the magnetic probe.

Operation

The magnetic probe attracts magnetic particles present inthe oil.

If it attracts sufficient particles to form a bridge across thegap, this will complete the electrical circuit between thetwo magnetic parts and thus illuminate an indicator on theinstrument panel.

The resistor is fitted to allow the installation of a testcircuit.

Note : Refer to aircraft documents for further details.




ELECTRICAL MAGNETIC PLUGS - DESCRIPTION - OPERATION

1

3

2

26

44

P003

60 K

Ω

+

1

3

2

26

44

P003

60 K

Ω

+

ELECTRICALCONNECTOR

PLUG BODY

O'RINGSEAL

HOUSING

GAP

Gap

SELF SEALINGVALVE


ENGINEAIRCRAFT

MAGNETICPLUG

Resistor

LIGHT "ON"BRIDGE OFPARTICLES

Firewall




OIL SYSTEM

OIL FILTER - GENERAL

Function

The filter retains particles that may be in the oil.

Position

- In the system : downstream of the pressure pump

- On the engine : on the left rear face of the accessorygearbox.


- Type : metal cartridge

- Filtering ability : 30 microns

- Mechanical pre-blockage indicator : ∆P 150 kPa(21.7 PSID)

- By-pass valve :• Setting : ∆P 200 kPa (29 PSID).

Main components

- Filter base


- Cover

- By-pass valve.




OIL FILTER - GENERAL

COVER

BY-PASSVALVE PRE-BLOCKAGE

INDICATOR

FILTERBASE

Type :Metal cartridge

Filtering ability :30 microns

Mechanical pre-blockageindicator :

∆P 150 kPa (21.7 PSID)

By-pass valve :∆P 200 kPa (29 PSID)




OIL SYSTEM

OIL FILTER - DESCRIPTION

Description

The main components of the filtering unit are the following :

- Filter base

- Filter cover

- Metal cartridge (filtering element)

- By-pass valve (fitted inside the filter base)

- Drain valve.

The filter base incorporates mounting points for thefollowing :


- Low oil pressure switch

- Oil pressure transmitter.




OIL FILTER - DESCRIPTION

FILTERCOVER

FILTERINGELEMENT

BY-PASSVALVE

DRAINVALVE

FILTERBASE

PRE-BLOCKAGEINDICATOR

LOW OILPRESSURE SWITCH

OIL PRESSURETRANSMITTER




OIL SYSTEM

OIL FILTER - OPERATION

Operation

Filtering (normal condition)

The oil supplied by the pressure pump passes through thefilter from outside to inside. The filtered oil then passes tothe engine for lubrication.

Pre-blockage

If the filter begins to become blocked the pressure differenceacross the filter increases. At a given difference(150 kPa ⁄ 21.7 PSID) a red mechanical indicator popsout. The oil continues to flow through the filter.

Blockage

If the pressure difference exceeds 200 kPa (29 PSID), theby-pass valve opens and unfiltered oil passes to the system.




OIL FILTER - OPERATION

NORMAL CONDITION

FILTERING(30 microns)

PRE-BLOCKAGEOIL FILTER ASSEMBLY

OPERATION OFTHE MECHANICALPRE-BLOCKAGE

INDICATOR(∆P 150 kPa / 21.7 PSID)

BLOCKAGE

OPERATION OF THEBY-PASS VALVE

(∆P 200 kPa / 29 PSID)




OIL SYSTEM

FILTER PRE-BLOCKAGE INDICATOR -GENERAL

Function

The indicator indicates the onset of filter blockage.

Position

On the left face of the filter housing.


- Type : differential

- Setting : ∆P 150 kPa (21.7 PSID)

- Indication : red indicator

- Manual rearming.

Main components

- Indicator body

- Indicator

- O'ring seals.




FILTER PRE-BLOCKAGE INDICATOR - GENERAL

Type :Differential

Setting :∆P 150 kPa (21.7 PSID)

Indication :Red indicator

Manual rearmingINDICATOR

INDICATORBODY

O'RING SEALS




OIL SYSTEM

FILTER PRE-BLOCKAGE INDICATOR -DESCRIPTION - OPERATION

Description

The pre-blockage indicator comprises the following parts :

- Indicator body including :• Filter upstream pressure inlet• Filter downstream pressure inlet

- Red indicator piston

- ∆P piston

- Transparent cover

- Thermal lock

- O'ring seals ensure the filter pre-blockage indicatorsealing.

Operation

Normal position

Filter downstream pressure plus spring pressure is greaterthan upstream pressure. The two pistons are held togetherby magnetic force. The indicator is not visible.

Pre-blockage

Filter upstream pressure exceeds downstream plus springpressure and the ∆P piston displaces.

This breaks the magnetic hold and the indicator piston ispushed out by its spring. The indicator is visible.

The bi-metallic thermal lock ensures that the indicatordoesn't operate when a large ∆P is caused by lowtemperature (locked below 50 °C (122 °F)).

It is rearmed by removing the cover and pushing in theindicator.




FILTER PRE-BLOCKAGE INDICATOR - DESCRIPTION - OPERATION

DESCRIPTION

FILTERUPSTREAMPRESSURE

FILTERDOWNSTREAM

PRESSURE

THERMALLOCK

REDINDICATOR

TRANSPARENTCOVER

INDICATORBODY

Downstreampressure

Downstreampressure

Upstreampressure

Upstreampressure

NORMAL CONDITION

PRE-BLOCKAGE CONDITION

OPERATION

Red indicator"out"

O RING SEALS

∆P PISTON

DESCRIPTION

< 50°C (122°F)

> 50°C (122°F)

∆P > 150 kPa (21.7 PSID)




OIL SYSTEM

OIL COOLER

Function

The oil cooler cools the oil after it has passed through theengine.

Position

- In the system : between the scavenge pumps and the tank

- On the aircraft : it is installed on the oil tank above theplenum chamber between the main gearbox and thefront firewall.


- Type : air-oil cooler

- By-pass thermostatic valve : 276 kPa (40 PSI) :• Full open when t° < 57 °C (135 °F)• Full closed when t° > 67 °C (153 °F)

- Supplied by aircraft manufacturer.

Main components

- Oil cooler

- By-pass thermostatic valve

- Unions (oil inlet and outlet).




OIL COOLER

Aircraft component

Type :Air/oil cooler

By-passThermostatic valve :

276 kPa (40 PSI)- Full open when : t° < 57 °C (135 °F)

- Full closed when : t° > 67 °C (153 °F)

OIL COOLER

Ambient air

BY-PASSTHERMOSTATIC

VALVE

FAN

OIL TANK

Oil inlet(from scavenge pumps)




OIL SYSTEM

CENTRIFUGAL BREATHER - GENERAL

Function

The centrifugal breather separates the oil from the air/oilmist created by the oil system.

Position

It is formed by the starter/generator drive gear in theaccessory gearbox.


- Type : centrifugal

- De-oiled air : through the rear of the hollow shaft.

Main components

- Gear wheel with air passage holes

- Splines for the starter generator drive.




CENTRIFUGAL BREATHER - GENERAL

Type :Centrifugal

De-oiled air :Through the rear

of the hollow shaft

GEAR PROVIDEDWITH BREATHER HOLES

SPLINES FOR THESTARTER GENERATOR DRIVE

DE-OILEDAIROIL MIST




OIL SYSTEM

CENTRIFUGAL BREATHER - DESCRIPTION -OPERATION

Description

The centrifugal breather is formed by the starter generatordrive gear. This gear is formed in one piece with a hollowshaft and has holes which provide a passage between thegearbox and the air vent.

The gear is supported by two ball bearings and has amagnetic carbon seal at each end.

The breather air outlet is at the rear end of the shaft, wherethe air passes into the gearbox outlet.

Operation

The centrifugal breather is driven by the intermediate gearof the accessory drive.

When the engine is running, the air/oil mist passes throughthe breather :

- Centrifugal force throws the oil droplets out into thegearbox where they fall to the bottom of the casing

- The de-oiled air passes out through the shaft, via agearbox passage, into an external pipe which dischargesinto the exhaust.




CENTRIFUGAL BREATHER - DESCRIPTION - OPERATION

MAGNETICCARBON SEAL

MAGNETICCARBON SEAL

AIR VENT

DE-OILED AIR

BEARING

OIL DROPLETS

OIL MIST- from accessory gearbox

- from gas generator bearings- from power turbine bearings

- from reduction gearbox

STARTERGENERATOR

DRIVE

BEARING




OIL SYSTEM

MAGNETIC PLUGS

Function

The magnetic plugs retain magnetic particles contained inthe oil to provide a rapid and frequent check of the internalcondition of the engine.

Position

In the system :

- One on the reduction gearbox scavenge return

- One on the accessory gearbox scavenge return.

On the engine :

- One at the bottom of the reduction gearbox

- One at the bottom of the accessory gearbox.

They are mounted on the left or the right side according tothe position of the engine in the helicopter.


- Type : single magnetic pole. Self-sealing housing.

Main components

- Self sealing housing :• Housing• O'ring seal• Valve• Spring

- Magnetic plug :• Magnet• O'ring seals• Locating pins.




MAGNETIC PLUGS

LOCATING PINS

Type :Single magnetic poleSelf-sealing housing

REMOVED POSITION

NORMAL POSITION

VALVE O'RINGSEAL

HOUSING

SPRING

MAGNET

O'RINGSEALS

O'RING SEALS

LOCATING PIN

MAGNETICPLUG

MAGNET




OIL SYSTEM

STRAINERS

Function

The strainers protect the scavenge pumps against largeparticles which might be in the oil.

Position

- In the system : they are fitted in each scavenge lineupstream of the scavenge pump

- On the engine :• Two strainers are located on the accessory gearbox

casing (reduction gearbox and accessory gearboxscavenge)

• One strainer is located on the oil pump assembly (gasgenerator rear bearing scavenge)


- Type : wide mesh filter.

Note : The rear bearing strainer is fitted in the electricalmagnetic plug housing (TU 208).

Main components

- Strainer body

- Wide mesh filter

- Mounting flange

- O'ring seal.

Functional description

A strainer is a wide mesh filter which retains any largeparticles which may be present in the oil in order to protectthe scavenge pumps.




STRAINERS

Type :Wide mesh filter

Gas generator rear bearingscavenge strainer

Reduction gearboxscavenge strainer

Accessory gearboxscavenge strainer

ACCESSORY GEARBOXAND REDUCTION GEARBOX

STRAINERS

GAS GENERATORREAR BEARING STRAINER

(Before Mod. TU 208)

GAS GENERATORREAR BEARING STRAINER

(After Mod. TU 208)

GAS GENERATORREAR BEARING

STRAINER

ACCESSORYGEARBOXSTRAINER

REDUCTIONGEARBOXSTRAINER




OIL SYSTEM

LOW OIL PRESSURE SWITCH - GENERAL

Function

The low oil pressure switch detects low oil system pressureand provides cockpit indication.

Position

- In the system : downstream of the filter

- On the engine : mounted on the filter base.


- Type : diaphragm pressure switch

- Setting : 90 or 130 kPa (13 or 18.9 PSI) (according toversion)

- Indication : warning light on instrument panel.

Main components

- Pressure switch body

- Electrical connector

- Mounting flange.




LOW OIL PRESSURE SWITCH - GENERAL

ELECTRICALCONNECTOR

PRESSURESWITCH BODY

MOUNTINGFLANGE

Type :Diaphragm pressure switch

Setting :90 or 130 kPa

(13 or 18.9 PSI)according to version

Indication :Light on instrument panel




OIL SYSTEM

LOW OIL PRESSURE SWITCH -DESCRIPTION - OPERATION

Description

The pressure switch comprises the following components :

- A diaphragm, subjected to the oil pressure downstreamof the filter

- A plunger, fixed to the diaphragm, to operate amicroswitch

- An electrical contact connected to a warning light on theinstrument panel

The pressure switch is secured by means of three screws onthe filter base.

An O'ring seal ensures the sealing between the pressureswitch and the filter base.

Operation

The pressure switch microswitch is open during normalengine operation.

If the oil pressure downstream of the filter reduces to lessthan 90 or 130 kPa (13 or 18.9 PSI) according to version,the diaphragm moves down. This causes the electricalcontact to close, completing the circuit of the low oilpressure warning light.




LOW OIL PRESSURE SWITCH - DESCRIPTION - OPERATION

3

1

2

3

1

2

OPERATION

ENGINEAIRCRAFT

+28 VDC+28 VDC

LOW OILPRESSURE SWITCH

LIGHT "ON"(instrument panel)

Firewall

CONTACT CLOSED(low oil pressure,

min<130 kPA / 18.9 PSI)

CONTACT OPEN(normal oil pressure)

DESCRIPTION

WARNING LIGHT(instrument panel)

ELECTRICAL CONTACT

From filter To lubrication

PLUNGER

DIAPHRAGM

+28 VDC




OIL SYSTEM

OIL PRESSURE TRANSMITTER

Function

The transmitter provides a signal of oil pressure to theinstrument panel.

Position

- In the system : in the supply system, downstream of thefilter

- On the engine : screwed into the filter base.


- Type : inductive or resistive according to version

- Output signal : voltage proportional to the oil pressure

- Supplied by the aircraft manufacturer.

Description

The transmitter includes :

- The transmitter body

- An electrical connector.

Operation

The inductive type transmitter is provided with a pistonconnected to a push rod which has a core at its end. As oilpressure increases the piston is pushed up, moving the corein a coil, causing a voltage output proportional to thepressure.




OIL PRESSURE TRANSMITTER

Aircraft component

Type :Inductive or resistive(according to version)

Output signal :Voltage proportional to the

oil pressure

ELECTRICAL CONNECTOR

TRANSMITTER BODY

OPERATION

DESCRIPTION

PISTONCOIL




OIL SYSTEM

OIL PIPES AND DUCTS

This description includes external pipes and internalpassages of the oil system.

Pipelines - General- Type of pipelines : rigid.

Tank to pressure pump- Flexible pipeline supplied by the aircraft manufacturer- Union on the pressure pump.

Pressure pump to filter- Internal passage in the casing.

Filter to system- Internal passage in the accessory gearbox casing.

Supply to the gas generator front bearings- External pipe- Union on the compressor casing.

Supply to the gas generator rear bearing- External pipe.

Supply to the power turbine bearings andreduction gearbox- Internal passage- Tube inside the output shaft protection tube.

Accessory gearbox supply- Internal passages.

Scavenge, engine front end- Internal passages.

Scavenge, gas generator rear bearing- External pipe- Union on pump.

Scavenge, engine rear part (power turbine andreduction gear)- Tube within output shaft protection tube- Internal passages.

Breathing- Gas generator front bearings - into accessory gearbox- Gas generator rear bearing - external pipe overboard- Reduction gearbox and power turbine - internal into

accessory gearbox.

Vent- External pipe to the exhaust pipe- External pipe from gas generator rear bearing overboard.




OIL PIPES AND DUCTS

TANKTO PUMP

SCAVENGE TOCOOLER AND TANK

SCAVENGETO PUMPS

FILTERTO ENGINE

PUMPTO FILTER

REAR BEARINGVENT

BREATHER



For training purposes only© Copyright - TURBOMECA - 2000 AIR SYSTEM

5-AIR SYSTEM

- Air system ...................................................................... 5.2

- Internal air system......................................................... 5.4

- Air tappings ................................................................... 5.8

- Compressor bleed valve ................................................ 5.10

- Air tapping unions ........................................................ 5.18

- Air pipes ......................................................................... 5.20 to 5.21




AIR SYSTEM

AIR SYSTEM

Function

The engine air system includes :

- An internal air system which ensures :• The pressurisation of the labyrinth seals• The cooling of the engine internal parts• The balance of forces on the rotating assemblies

- Air tappings which ensure :• Bleed valve operation• Start injector ventilation• Aircraft air system supply• Air supply to the FCU metering unit

- The compressor bleed valve.

Note : Refer to the various systems for the location,characteristics and operation.




AIR SYSTEM

COMPRESSOR BLEEDVALVE

AIR TAPPINGS - Start injector ventilation- Bleed valve operation

- Aircraft air system supply- Air supply to the FCU metering unit

INTERNAL AIR SYSTEM - Pressurisation of labyrinth seals

- Cooling of internal parts- Balance of forces on the rotating assemblies




AIR SYSTEM

INTERNAL AIR SYSTEM - GENERAL

Function

The internal air system pressurises the labyrinth seals,cools certain parts and provides a balancing of forces.

Position

All the parts of the system are internal except thepressurisation of the power turbine labyrinth which issupplied by an external pipe.


- Type : air pressure tapping with a calibrated flow

- Axial compressor outlet pressure : 160 kPa (23.2 PSI)

- Centrifugal compressor outlet pressure : 820 kPa(118.9 PSI)

- Air flow : ≈ 2 % of the engine total flow.

Main components

- Internal passages

- Calibrated orifices

- External pipe for the power turbine labyrinthpressurisation.




INTERNAL AIR SYSTEM - GENERAL

Type :Air pressure tapping with

a calibrated flow

Axial compressoroutlet pressure :

160 kPa (23.2 PSI)

Centrifugal compressoroutlet pressure :

820 kPa (118.9 PSI)

Air flow :≈ 2 % of engine total flow

INTERNAL AIR SYSTEM

- Internal passages- Calibrated orifices

External pipe for thepower turbine labyrinth pressurisation




AIR SYSTEM

INTERNAL AIR SYSTEM - FUNCTIONALDESCRIPTION

The internal air system can be considered in three parts :the front section, the gas generator HP section and thepower turbine section.

Front section

Air tapped from the centrifugal compressor inlet is used topressurise the front bearing labyrinths. There is a verysmall flow of air into the bearing chamber.

Air tapped from the same point is discharged through thecompressor bleed valve, mounted on the compressor casing(see compressor bleed valve).

Gas generator section

Air tapped from the centrifugal compressor tip passesdown the rear face of the compressor wheel, through thecurvic couplings, the hollow shaft and internal passages. Itis used to :

- Cool the front and rear faces of the gas generatorturbines (discharging into the gas flow)

- Pressurise the labyrinth seals of the gas generator rearbearing (small flow into the bearing housing) and theinjection wheel.

The air from the centrifugal compressor outlet flowsthrough the hollow nozzle guide vanes (1st stage) andthrough holes in the shroud. It is used to cool the nozzleguide vane and the front face of the gas generator turbine.

The centrifugal compressor casing is fitted with air tappingpoints. This air is called clean air as it is out of the main airflow stream.

Power turbine section

Air tapped from the combustion chamber is taken by anexternal pipe to the reduction gearbox casing. It thenpasses through internal passages to pressurise the labyrinthseal on the power turbine shaft and to cool the rear face ofthe power turbine.

A circulation of P0 air, induced by venturi effect, cools thegas generator rear bearing chamber, and then flows throughthe power turbine nozzle guide vanes, cooling them andthen joins the gas flow.




INTERNAL AIR SYSTEM - FUNCTIONAL DESCRIPTION

P0

POWER TURBINE SECTION

GAS GENERATOR SECTIONFRONT SECTION




AIR SYSTEM

Aircraft services

Compressor delivery air is tapped off for use in variousaircraft systems.

The engine has two air tapping unions (used for the aircraftservices) on the centrifugal compressor casing.

Note : The use of this bleed is restricted during take-off.

Bleed valve operation

Compressor delivery air is tapped to operate the compressorbleed valve.

Air intake anti-icing

On the 1S version P2 air is used for air intake anti-icing.

The system includes an air tapping point, a pipeline whichpasses forward through the front firewall, an electro-valve, a pressure switch and the double skinned air intakeduct.

AIR TAPPINGS

Function

Air tappings are used for :

- Fuel control

- Start injector ventilation

- Aircraft services

- Bleed valve operation

- Air intake anti-icing.

Fuel control

P2 air is used for the acceleration control unit and the minfuel flow limiter (in some versions 1C, 1D, 1M, ... ).

The system includes a pressure tapping and a pipe betweenthe tapping union and the FCU.

Start injector ventilation

Compressor delivery air is used to ventilate the startinjectors to avoid blockage by the carbonisation of unburntfuel.

The system comprises a tapping union and a pipe connectedto the start electro-valve.




AIR TAPPINGS

P2

P0

P0

P2

AIRCRAFT SERVICESAND AIR INTAKEANTI-ICING (1S)

SIGNAL FOR THEFUEL CONTROL

BLEED VALVEOPERATION

START INJECTORVENTILATION




AIR SYSTEM

COMPRESSOR BLEED VALVE - GENERAL

Function

The compressor bleed valve prevents axial compressorsurge.

Position

- In the system : between the axial and centrifugalcompressors

- On the engine : at the top of the counter-casing.


- Type : pneumatic or electrical (according to version)

- Control :• by P2/P0 pressure ratio (pneumatic type)• as a function of N1 (electrical type).

Note : The air can be discharged under the cowling inorder to improve cooling of the enginecompartment.

Principle

The valve prevents compressor surge by bleeding off acertain quantity of air tapped from the axial compressoroutlet. When the valve is open, the discharge of air causesthe air flow through the axial compressor to increase thusmoving the working line away from the surge line.




COMPRESSOR BLEED VALVE - GENERAL

G

P2/P0

Surge line

Working line(valve closed)

Working line(valve open)

Type :Pneumatic or electrical(according to version)

Control :- P2/P0 pressure ratio

(pneumatic type)- As a function of N1

(electrical type)

ADMISSIONOF AMBIENT AIR

COMPRESSION ANDSTRAIGHTENING OF THE AIR

P1' : AIR DISCHARGEDTHROUGH THE COMPRESSOR

BLEED VALVE




AIR SYSTEM

ELECTRO-PNEUMATICCOMPRESSOR BLEED VALVE -DESCRIPTION - OPERATION

Description

This compressor bleed valve includes 3 main parts : thetachometer box, the control electro-valve and the bleedvalve.

Tachometer box

It operates a relay controlled by a speed signal from the N1tachometer transmitter.

Control electro-valve

It admits P2 air to close the valve when it is electricallysupplied.

Bleed valve

It includes a spring loaded piston subjected to P2 pressure.The piston operates the valve.

Operation

Closing

When the N1 reaches 96 % the tachometer box closes theelectrical contact which actuates the control electro-valveto the open position. P2 pressure pushes the piston whichcloses the bleed valve.

Opening

When the N1 decreases below 94 %, the tachometer boxopens the electrical contact and the spring moves theelectro-valve to the closed position. The spring pushes thepiston which opens the bleed valve.




ELECTRO-PNEUMATIC COMPRESSOR BLEED VALVEDESCRIPTION - OPERATION

N1 P1'

P2

+

96% 94%

GRILL ON P1'AIR DISCHARGE

P2 AIR SUPPLY

BLEED VALVE

CONTROL ELECTRO-VALVE

TACHOMETER BOX




AIR SYSTEM

PNEUMATIC COMPRESSOR BLEED VALVE -DESCRIPTION - OPERATION

The compressor bleed valve includes 3 main parts : thedetection capsule, the intermediate stage and the bleedvalve.

Detection capsule

It is subjected to P2/P0 pressure ratio and controls the airleak downstream of the calibrated orifice B.

It is fitted with a filter at the inlet.

Intermediate stage

It includes a diaphragm which is subjected to the pressuredownstream of B. The diaphragm controls the leak whichdetermines the pressure downstream of the calibratedorifice A.

Bleed valve

It includes a spring loaded piston subjected to a downstreampressure. The piston opens or closes the P1' air passage.

It also includes a microswitch, operated by the piston,which provides indication of the bleed valve position.

Operation

Closing

When the gas generator rotation speed N1 increases, thecompression ratio P2/P0 increases and beyond a certainvalue :

- The pressure becomes sufficient to deform the detectioncapsule which closes the leak

- The pressure downstream of the calibrated orifice Bincreases

- The diaphragm of the intermediate stage closes the leak

- The pressure downstream of the calibrated orifice Aincreases

- The piston moves down under P2 pressure and the valvecloses and stops the P1' air discharge.

Opening

The P2/P0 ratio is not sufficient to activate the capsule andthere is an air leak downstream of the calibrated orifices.The piston is not actuated and the valve is open.

A certain amount of air, tapped from the centrifugalcompressor inlet, is discharged overboard.




PNEUMATIC COMPRESSOR BLEED VALVE -DESCRIPTION - OPERATION

P1'

A B

P0P1'

P2

BLEEDVALVE

INTERMEDIATESTAGE

MICROSWITCH INDICATOR

DETECTIONCAPSULE

BLEEDVALVE

INTERMEDIATESTAGE

DETECTIONCAPSULE

FILTER

FILTER




AIR SYSTEM

BUTTERFLY TYPE COMPRESSOR BLEEDVALVE - DESCRIPTION - OPERATION

Description

The compressor bleed valve includes 3 main parts : thedetection capsule, the intermediate stage and the bleedvalve.

Detection capsule

It is subjected to P2/P0 pressure ratio and controls the airleak downstream of the calibrated orifice B.

It is fitted with a filter at the inlet.

Intermediate stage

It includes a diaphragm which is subjected to the pressuredownstream of B. The diaphragm controls the leak whichdetermines the pressure downstream of the calibratedorifice A.

Bleed valve

It includes a spring loaded piston subjected to pressuredownstream of orifice A. The piston actuates the butterflyvalve by means of a rack and pinion mechanism.

It also includes a microswitch, operated by the piston,which gives the position of the bleed valve by means of alight ("on" valve "open").

Operation

Closing

When the gas generator rotation speed N1 increases, thecompression ratio P2/P0 increases and beyond a certainvalue :

- The pressure becomes sufficient to deform the detectioncapsule which closes the leak

- The pressure downstream of the calibrated orifice Bincreases

- The diaphragm of the intermediate stage closes the leak

- The pressure downstream of the calibrated orifice Aincreases

- The piston moves down under P2 pressure and rotatesthe butterfly valve through the rack and pinionmechanism. The valve closes and stops the air discharge.

Opening

The P2/P0 ratio is not sufficient to activate the capsulesand there is an air leak downstream of the calibratedorifices. The piston is not actuated and the butterfly valveis open.

A certain amount of air, tapped from the centrifugalcompressor inlet, is discharged overboard.




BUTTERFLY COMPRESSOR BLEED VALVE -DESCRIPTION - OPERATION

A B

P1'

INTERMEDIATESTAGE

RACK

PISTON

PINION

MICROSWITCH DETECTION CAPSULE

P2 AIR

P0 AIR

FILTER

BUTTERFLY VALVE




AIR SYSTEM

AIR TAPPING UNIONS

These pages summarise the various air tappings : startinjector ventilation, bleed valve control, power turbinelabyrinth pressurisation, aircraft supply.

They are located on the centrifugal compressor casingfront face. The air in this zone is considered clean air as itis out of the main air stream and thus contains very littledebris.

At 100 % N1, in standard conditions, this air has a pressureof 820 kPa (118.9 PSI) and a temperature of 320 °C(608 °F).

Start injector ventilation

Union with a restrictor (ø 1 mm).

Air flow : very low.

Power turbine labyrinth pressurisation

Union (ø 1.9 mm).

Air flow : very low.

Aircraft services

Union.

Air flow : 100 g/s (0.22 lb/sec.) Max.

Compressor bleed valve

Union (ø 1.9 mm).

Air flow : negligible.

Metering unit supply (FCU)

Union (ø 1.9 mm).

Air flow : nil.




AIR TAPPING UNIONS

Ø1 mm

Ø1,9 mm

Ø1,9 mm

7 holes Ø1,5 mm

AIR BLEED FORAIRCRAFT SYSTEM

SUPPLY FOR POWERTURBINE LABYRINTH

PRESSURISATION

SUPPLY FOR VENTILATIONOF THE START INJECTORS

AIR BLEED FORAIRCRAFT SYSTEM

SUPPLY TO CONTROL THECOMPRESSOR BLEED VALVE

SUPPLY TO FUELCONTROL UNIT




AIR SYSTEM

AIR PIPES

This part considers the external air pipes of the air system.

Pipes - General

- Type of pipes : stainless steel, rigid

- Type of unions : QUINSON union.

P2 air pipe for the control of the compressor bleedvalve

Air pipe to supply the Fuel Control Unit

Air pipe for the ventilation of the start injectors

Air pipe for the pressurisation of the power turbinelabyrinth.




AIR PIPES

P2 AIR PIPE FOR THE COMPRESSOR BLEED

VALVE CONTROLAIR PIPE FOR THE VENTILATION

OF THE START INJECTORS

AIR PIPE FOR THEPRESSURISATION OF THE

POWER TURBINE LABYRINTH

AIR PIPE TO SUPPLYTHE FUEL CONTROL UNIT



For training purposes only© Copyright - TURBOMECA - 2000 FUEL SYSTEM

6-FUEL SYSTEM

- Fuel system ..................................................................... 6.2

- Fuel Control Unit........................................................... 6.12

• Fuel pump ................................................................................... 6.14

• Fuel filter ..................................................................................... 6.18

• Manual control ........................................................................... 6.24

• Metering unit .............................................................................. 6.28

- Overspeed and drain valve ........................................... 6.30

- Start injector electro-valve ........................................... 6.36

- Main injection system ................................................... 6.42

- Start injectors ................................................................ 6.46

- Combustion chamber drain valve ................................ 6.50

- Fuel pipes........................................................................ 6.54 to 6.55




FUEL SYSTEM

Main components

- Fuel control unit• Fuel pump• Filter• Valves• Metering unit.

- Overspeed and drain valve

- Start injector electro-valve

- Injection system.

FUEL SYSTEM - GENERAL (1)

Function

The fuel system ensures fuel supply, injection, distributionand metering.

Position

All the system components are mounted on the engineexcept the tachometer box (twin-engine configuration).


- Supply by the aircraft system and the engine pump

- Centrifugal main injection and start injection by injectors

- Manual control

- Fuel control : hydromechanical controlling and meteringdevice.





START INJECTORELECTRO-VALVE

START INJECTORS

INJECTIONWHEEL

F.C.U. OVERSPEED ANDDRAIN VALVE

AIRCRAFTTANK

TACHOMETER BOX(TWIN-ENGINE VERSION)




FUEL SYSTEM


Low pressure fuel system (1S, 1E versions)

Function

This system is designed for aircraft without a boosterpump and assures the supply to the H.P. pump.

Position

All the components are fitted on a bracket on the undersideof the protection tube.

Main components

- Metal Filter (10 µ)

- Min pressure switch

- By-pass valve

- Pressure transmitter (optional)

- Manual valve

- Ejector

- Astatic valve


- Jet.


The ejector pump is supplied with fuel from the HP pumpvia the astatic valve which opens at a pressure of 550 kPa.The ejector pump ensures a positive supply of fuel to theHP pump inlet.

A connection between the two engines permits priming ofone engine by the other. Priming can also be carried outusing a hand pump.




LOW PRESSURE FUEL SYSTEM (1S, 1E VERSIONS)FUEL SYSTEM - GENERAL (2)

PRIMING SUPPLYTO OTHER ENGINE

(version 1S)

FUEL SUCTIONFROM TANK

HP PUMPPRESSURE(FCU)

ASTATICVALVE

TO BPFILTER

HP PUMP PRESSURE(FCU)

FILTER

EJECTOR

MANUALVALVE

BY-PASSVALVE



JET EJECTOR

TO HP PUMP(FCU)

EJECTOR

MIN PRESSURESWITCH

MIN PRESSURESWITCH

PRESSURETRANSMITTER

(optional)

BY-PASSVALVE

MANUALVALVE

ASTATICVALVE


BPFILTER





FUEL SYSTEM

FUEL SYSTEM - DESCRIPTION

This part shows the main components of the fuel system.

Fuel pump

Gear type pump, mechanically driven by the accessorygearbox and fitted with a pressure relief valve.

Filter

The filter has a pre-blockage indicator (according toversion) and a by-pass valve.

Main and auxiliary valves

The main and auxiliary valves are controlled by the controllever which acts at the same time on the accelerationcontrol unit cam.

Metering device

The hydromechanical controller acts on the meteringneedle (see next chapter).

Valves

- Non-return valve

- Pressurising valve

- Overspeed and drain valve


- Purge valve.

Injection system

- Start injectors (2)

- Centrifugal injection wheel.




FUEL SYSTEM - DESCRIPTION

PRE-BLOCKAGEINDICATOR START INJECTOR

ELECTRO-VALVE

START INJECTORS

PURGE VALVE

CONTROL LEVER

OVERSPEED ANDDRAIN VALVE

INJECTION WHEEL

FUEL PUMP

PRESSURE RELIEFVALVE

FILTER

FILTER BY-PASSVALVE

AUXILIARY VALVE

MAIN VALVE

CAM

METERINGDEVICE

NON-RETURNVALVE

PRESSURISINGVALVE




FUEL SYSTEM

FUEL SYSTEM - OPERATION (1)

This part deals with the following operating phases : pre-start, starting, normal operation, manual control and shut-down.

Pre-start

- The pump is not operating and there is no pressure in thesystem

- The main and auxiliary valves are closed

- The constant ∆P valve is closed

- The metering needle is closed by the acceleration controlcam

- The following valves are closed :• non return valve• pressurising valve• overspeed & drain valve• purge valve

- The start injector electro-valve is closed.

Purge of the system

During the initial phase of starting, the fuel supplied fromthe aircraft system flows into the F.C.U., through the non-return valve and to the purge valve which opens andreturns the fuel to the tank. The purpose of this phase is toexpel any air which may be in the system.

Starting

When engine start is selected, the start accessories areelectrically supplied.

The pump is driven and supplies the start injectors and thenthe centrifugal injection wheel.

The constant ∆P valve operates and returns the excess fuelto the pump inlet.

The fuel flow is controlled by the movement of the controllever.

At 45 % N1, the start accessories are de-energised byreleasing the start button and the start injectors are ventilatedby P2 air pressure.

The control lever is moved to the flight position,progressively opening the main valve to accelerate theengine until the hydromechanical control takes over.




PRE-START - PURGE - STARTINGFUEL SYSTEM - OPERATION (1)




FUEL SYSTEM


Normal running

The required fuel flow is metered by the metering needle.The metering needle position is determined by thehydromechanical control system (refer to "CONTROLSYSTEM" chapter).

The fuel pump always supplies more fuel than the enginerequires. The excess fuel returns to the pump inlet throughthe constant ∆P valve.

The start injectors are continuously ventilated by P2 aircirculation.

Shut-down

The lever is pulled fully rearward, closing the main valvewhich cuts the fuel flow to the engine causing it to rundown & stop.

Manual control

The manual control is used for starting and stopping theengine. It can also be used in case of a control systemfailure.




NORMAL RUNNING - SHUT-DOWN - MANUAL CONTROL





FUEL SYSTEM

FUEL CONTROL UNIT - GENERAL

Function

The Fuel Control Unit ensures fuel supply and fuel flowmetering.

Position

- On the left front face of the accessory gearbox.


- Type : hydro-mechanical

- Mounting : clamp

- Replaceable components :• Filter• Pre-blockage indicator (according to version).

Main components

- Fuel pump

- Filter

- Pre-blockage indicator (according to version)

- Valves and cam

- Metering unit.




FUEL CONTROL UNIT - GENERAL

FILTER(position according

to version)

VALVE SHAFT

MOUNTINGCLAMP


(according to version)

CAM




FUEL SYSTEM

FUEL PUMP - GENERAL

Function

The pump assembly supplies fuel under determinedconditions of pressure and flow.

Position

- In the FCU.


- Spur gear type

- Pressure relief valve setting : 3300 kPa (478.5 PSI)

- Rotation speed : proportional to N1 speed.

Main components

- Drive gear

- Driven gear

- Drive shaft

- Pressure relief valve.




FUEL PUMP - GENERAL

Type :Spur gear

Pressure relief valvesetting :

3300 kPa (478.5 PSI)

Rotation speed :Proportional to

N1 speed

DRIVENGEAR

DRIVEGEAR

SHAFT




FUEL SYSTEM

FUEL PUMP - DESCRIPTION - OPERATION

Description

The assembly comprises the pressure pump and the pressurerelief valve.

Fuel pump

It is a spur gear type pump which has a drive gear and adriven gear, the drive gear being driven by the accessorydrive via the pump drive shaft which is a quill shaft. Twolip seals, with a drain between them prevent fuel fromentering the accessory gearbox.

The pump is supplied with fuel from the aircraft system.

Pressure relief valve

It is a conical valve held closed by a spring.

Pressure reducing valve

This is a diaphragm valve which provides a constantpressure output of approx. 400 kPa (58 psi) for the hydraulicsupply of the hydromechanical governor.

Operation

Fuel pump

The pump receives fuel from the aircraft LP system. Thefuel is drawn in by the pump, it passes between the gearsand the casing and is forced out under pressure.

Pressure relief valve

If the pump outlet pressure exceeds 3300 kPa (478.5 PSI)the pressure relief valve will open and allow fuel to returnto the pump inlet thus limiting the maximum pressure inthe system.

Pressure reducing valve

The diaphragm is subjected to fuel pressure on one sideopposed by spring pressure on the other side. The positionof the diaphragm determines the position of the valve.When pump outlet pressure increases the diaphragm movesup, reducing the valve opening and thus maintaining aconstant downstream pressure.




FUEL PUMP - DESCRIPTION - OPERATION

PRESSURERELIEF VALVE FUEL PUMP

DRIVEGEAR DRAIN SEALS SHAFT

DRIVENGEAR

FUEL PUMPPRESSURE RELIEF VALVE

PUMP


PRESSUREREDUCING

VALVE




FUEL SYSTEM

FUEL FILTER - GENERAL

Function

The filter retains any particles that may be in the fuel inorder to protect the metering unit components.

Position

- In the system : between the pump and the metering unit

- On the engine : lower part of FCU.


- Type : metal cartridge

- Filtering ability : 20 microns

- By-pass valve setting : ∆P 200 kPa (39 PSID)

- Pre-blockage pressure switch setting : ∆P 150 kPa(21.75 PSID).

Main components

- Filter

- Pre-blockage indicator (according to version)

- By-pass valve.




FUEL FILTER - GENERAL

Type :Metal cartridge

Filtering ability :20 microns

By-pass valve setting :∆P 200 kPa (39 PSID)

Pre-blockage pressureswitch setting :

∆P 150 kPa (21.75 PSID)


(according to version)

FILTER ANDBY-PASS VALVE(position according

to version)




FUEL SYSTEM

FUEL FILTER - DESCRIPTION

The assembly comprises the base, the filtering element,the by-pass valve and the pre-blockage indicator.

Filtering element

It is a metal cartridge with a filtering ability of 20 microns.

O'ring seals ensure the sealing between the cartridge andthe filter housing.

By-pass valve

This valve ensures a fuel flow to the metering unit in theevent of filter blockage. It is subjected on one side to filterupstream pressure and on the other side to downstreampressure plus the force of a spring.

Pre-blockage indicator

This is a differential visual indicator. It includes a redindicator which pops out in a transparent cover when thepressure difference across the filtering element exceeds agiven value.

It comprises :

- A body

- A red indicator

- Two O'ring seals which ensure the sealing between theindicator and the FCU body and between the upstreampressure inlet and the downstream pressure inlet.

Note : The pre-blockage indicator is not installed in allversions.




FUEL FILTER - DESCRIPTION

RED INDICATOR TRANSPARENTCOVER

BODY

PRE-BLOCKAGE INDICATOR

Upstreampressure

Downstreampressure

O'RINGSEALS

FILTERINGCARTRIDGE

FILTERBASE

O'RINGSEAL

PIN CUP

BY-PASSVALVE

FILTER




FUEL SYSTEM

FUEL FILTER - OPERATION

The operation is considered in normal operation, pre-blockage and blockage.

Normal operation

The fuel from the pump enters the fuel filter and flowsthrough the filtering element (from outside to inside).

The filtering element retains particles larger than 20microns. The fuel then flows to the metering unit.

Pre-blockage

When the filter becomes dirty, the pressure differenceacross the filtering element increases.

If the pressure difference becomes higher than 150 kPa(21.75 PSID) the red visual indicator pops out.

Note : The pre-blockage indicator can be reset byremoving the cover and pushing in the indicator.

Blockage

When the pressure difference across the filtering elementexceeds 200 kPa (39 PSID), the by-pass valve opens andcauses the fuel flow to by-pass the filter.




FUEL FILTER - OPERATION

OPENING OFBY-PASS VALVE

∆P: 200 kPa (39 PSID)

BLOCKAGE

FILTERBLOCKAGE

ONSET

BY-PASSVALVE

PRE-BLOCKAGE

FILTERBLOCKAGE

FUELFILTER


INDICATOR OPERATION :∆P 150 kPa (21.75 PSID)

(THE RED VISUALINDICATOR APPEARS)

NORMAL OPERATION




FUEL SYSTEM

MANUAL CONTROL - GENERAL

Function

A mechanical control linked to the fuel control unit permitsstarting control, acceleration to nominal speed and stopping.

It can also be used as a manual fuel flow control in theevent of automatic control failure.

Position

- Interface on the left side of the FCU.

Main components

- Valve shaft

- Cam control lever

- Cam.




MANUAL CONTROL - GENERAL

CAM

VALVESHAFT

CAM CONTROLLEVER




FUEL SYSTEM

Operation

Stop position

- position a : the two valves are closed, the cammaintains the metering needle closed.

Start and acceleration range

- position b : progressive opening of the main valve ; thecam frees the metering needle above a certain angle.

Flight position

- position c : the main valve is fully open.

"Emergency + range"

- position d : progressive opening of the auxiliary valve,the main valve remaining open.

"Emergency - range"

In case of automatic control failure supplying too muchfuel to the engine, the control lever can be placed in thestart range to reduce the fuel flow.

MANUAL CONTROL - DESCRIPTION -OPERATION

Description

The manual control includes the following devices :

- The main valve which permits acceleration controlduring the start phase and the use of the "emergency -"range

- The auxiliary valve which is used for the "emergency +range"

- The acceleration control cam which controls the positionof the metering needle for starting.




MANUAL CONTROL - DESCRIPTION - OPERATION

90°

62°52°

5°45°

c

da

P2

b

MAINVALVE

ACCELERATIONCONTROL CAM

AUXILIARYVALVE

CONTROLLEVER




FUEL SYSTEM

METERING UNIT - GENERAL

Function

It ensures constant metering of the fuel injected into thecombustion chamber.

Position

- In the system : downstream of the pump

- On the engine : in the FCU.


- Profiled needle which moves in a calibrated orifice.

- The metering needle is controlled by the hydromechanicalcontrol system.

Main components

- Constant ∆P valve

- Metering needle.

Note : See the "engine control" chapter for furtherdescription.




METERING UNIT - GENERAL

CONSTANT ∆PVALVE

METERING NEEDLE(controlled by hydromechanical

control system)




FUEL SYSTEM

OVERSPEED AND DRAIN VALVE - GENERAL

Function

The valve controls the fuel supply to the injection wheel :

- Fuel supply during starting and in operation

- Fuel shut-off and draining of the injection wheel duringshut-down.

The assembly also includes an electro-valve for a rapidengine shut-down in the event of power turbine overspeed(only on twin-engine aircraft).

Position

- Lower left side of the combustion chamber casing.


Pressurising valve setting : 180 kPa (26.1 PSI).

Manual control system

- Pressurising valve

- Overspeed and drain valve body

- Overspeed electro-valve.




OVERSPEED AND DRAIN VALVE - GENERAL

PRESSURISINGVALVE

OVERSPEED ANDDRAIN VALVE BODY

OVERSPEEDELECTRO-VALVE

(only on twin-engineversion)




FUEL SYSTEM

OVERSPEED AND DRAIN VALVE -DESCRIPTION

The assembly includes the pressurising valve, the dualvalve and the overspeed electro-valve.

Pressurising valve

This valve is operated by fuel pressure. Its main purpose isto ensure priority flow to the start injectors during theignition phase.

Dual valve

It is actuated by a diaphragm subjected to fuel pressure :one valve to open and close the fuel passage to the injectionwheel, the other one to drain the fuel remaining in theinjection wheel.

Overspeed electro-valve

Only on twin engine configuration. It drains the fuel underthe diaphragm in case of N2 overspeed thus causing thedual valve to close and the engine to automatically shutdown.




OVERSPEED AND DRAIN VALVE - DESCRIPTION

PRESSURISINGVALVE

DUAL VALVE(ball valve)

DIAPHRAGM

FUELINLET

FUELINLET

FUEL OUTLET TODUAL VALVE

FUELOUTLET

DRAINING


(twin-engine)

PUMP PRESSURE

PRESSURISINGVALVE

DUAL VALVE(overspeed and drain valve)




FUEL SYSTEM

OVERSPEED AND DRAIN VALVE -OPERATION

Two operating positions can be considered : engine running(fuel supply) and engine stopped (fuel shut-off and drainingof the wheel).

Engine running position

As soon as the fuel pressure reaches the setting of thepressurising valve (180 kPa/26.10 PSI), the pressure isadmitted under the diaphragm which causes the closing ofthe drain valve and the opening of the fuel supply valve.The fuel flows to the injection wheel and is sprayed into thecombustion chamber.

Stop position

The normal stop selection (closing of the main valve by thecontrol lever) results in a decrease of injection pressure.The pressurising valve closes. The pressure decreasesbelow the diaphragm and the dual valve moves downunder pump pressure on the upper diaphragm. The drainvalve opens (draining of fuel to prevent blockage of theinjection manifold by carbonization of the remainingfuel). When the engine is completely stopped, the drainvalve closes under the force of its spring.

Overspeed shut-down

Engine shut-down can also be affected by the electro-valve which, when opened, causes the pressure to decreasebelow the diaphragm and the valve to move down (shut-down in case of power turbine overspeed for the enginesprovided with this safety system).

Note : The detail shows the dual valve position aftercomplete shut-down of the engine.




OVERSPEED AND DRAIN VALVE - OPERATION

DETAIL(after shut-down)

Overspeedelectro-valve

ENGINE RUNNING POSITION DURING SHUT-DOWN




FUEL SYSTEM

START INJECTOR ELECTRO-VALVE -GENERAL

Function

The start injector electro-valve ensures the fuel distributionto the two injectors during engine starting.

Position

Upper part of the combustion chamber casing.


- Re-injection prohibit switch setting :≈ 92 kPa (13.34 PSI) => 45 % N1

- Purge valve setting :• opening at 5 kPa (0.725 PSI)• closing at 120 kPa (17.4 PSI).

Main components


- P2 ball valve

- Re-injection prohibit switch

- Purge valve.




START INJECTOR ELECTRO-VALVE - GENERAL

P2

PUMPPRESSURE

PURGETO TANK

FUELINLETFUEL OUTLET

TO INJECTORS


AND REINJECTION PROHIBIT SWITCH

P2BALL VALVE

PURGEVALVE




FUEL SYSTEM

START INJECTOR ELECTRO-VALVE -DESCRIPTION

The assembly includes the electro-valve, the P2 ball valve,the reinjection prohibit switch and the purge valve.

Electro-valve

It opens when energised during starting.

P2 ball valve

The valve admits P2 air pressure to ventilate the injectorsafter the starting phase.

Reinjection prohibit switch

It prevents any electrical supply to the electro-valve whenthe P2 pressure reaches a certain value obtained at the endof starting and thus any reinjection.

Purge valve

It ensures a pre-start purge by returning a certain quantityof fuel to the tank. As soon as start is selected, the pumppressure acts on the diaphragm to stop the purge. Theauxiliary valve relieves the pressure under the diaphragmafter the engine has stopped.




START INJECTOR ELECTRO-VALVE - DESCRIPTION

P2

ELECTRO-VALVERE-INJECTIONPROHIBIT SWITCH RETURN

TO TANK

PUMPPRESSURE

FUELINLET

AUXILIARYVALVE

DIAPHRAGMAND VALVE

BALLVALVE

START INJECTOR ELECTRO-VALVE PURGE VALVE




FUEL SYSTEM

START INJECTOR ELECTRO-VALVE -OPERATION

Three main operating phases can be considered : purgebefore start, injection during start and ventilation in normaloperation.

Purge of the system before starting

During the initial phase of starting, the fuel supplied fromthe aircraft system flows into the F.C.U., through the non-return valve and to the purge valve which opens andreturns the fuel to the tank. The purpose of this phase is toexpel any air which may be in the system.

Fuel injection

When starting is selected, the engine pump pressureincreases rapidly and closes the purge valve, the electro-valve is energised open and the fuel supplied by the enginepump flows to the 2 injectors which spray it into thecombustion chamber. The fuel is then ignited by the sparksof the igniter plugs.

Ventilation of the injectors

At the end of starting, the supply to the electro-valve is cutand the valve closes. The air under compressor pressure P2(which has increased in the meantime) lifts the ball of thevalve and flows to ventilate the injectors. This ventilationcontinues as long as the engine operates to prevent blockageof the injectors by carbonization of the remaining fuel. TheP2 pressure actuates the pressure switch to prevent any re-injection which could cause a flame-out by suddenlyreducing fuel flow to the injection wheel.




START INJECTOR ELECTRO-VALVE - OPERATION

PURGING OF THE SYSTEMBEFORE STARTING

FUEL INJECTION

PUMPPRESSURE

PUMPPRESSURE

VENTILATIONOF THE INJECTORS




FUEL SYSTEM

MAIN INJECTION SYSTEM - GENERAL

Function

The injection system sprays fuel into the combustionchamber to give stable and efficient combustion.

Position

- On the engine : inside the combustion chamber. Theinjection wheel is mounted between the centrifugalcompressor and the turbine shaft. The distributor isbolted to the diffuser backplate.


- Type : centrifugal injection

- Radial fuel supply.

Main components

- Inlet union

- Supply pipe

- Distributor

- Wheel with spraying jets.




MAIN INJECTION SYSTEM - GENERAL

Type :Centrifugal injection,

radial fuel supply

CENTRIFUGAL INJECTION WHEEL(with spraying jets)

SUPPLY PIPE

FUEL INLETUNION

DISTRIBUTOR




FUEL SYSTEM

MAIN INJECTION SYSTEM - DESCRIPTION -OPERATION

Description

The injection system comprises the fuel inlet union, theinternal supply pipe and the centrifugal injection assembly-distributor and wheel.

Fuel inlet union

Fitted at the lower right front face of the compressorcasing, it has a plug to test the sealing of the union.

Internal supply pipe

This pipe connects the inlet union to the fuel distributor. Itis fitted between the front swirl plate and the diffuser back-plate.

Centrifugal injection assembly

This assembly consists of a stationary distributor and awheel. The distributor, fitted onto the diffuser back-plate,is drilled with axial holes which deliver the fuel to thewheel. The injection wheel, mounted by curvic couplingsbetween the compressor and the turbine shaft, is drilledwith radial holes which form the fuel spraying jets. Sealingbetween the distributor and the wheel is achieved bypressurised labyrinth seals.

Operation

The fuel is delivered to the distributor by the internalsupply pipe.

It passes through the distributor's axial holes into thechamber in the injection wheel.

As the injection wheel is rotating at high speed (N1) thefuel is centrifuged out through the radial holes and issprayed between the two swirl plates.

It should be noted that the injection pressure is supplied bythe centrifugal force and therefore the fuel system does notrequire very high pressures.

The injection wheel fuel chamber is sealed by pressurisedlabyrinth seals. There is a small air flow into the fuelchamber. During shut-down the fuel remaining in thesystem is purged via the overspeed and drain valve.




MAIN INJECTION SYSTEM - DESCRIPTION - OPERATION

FUEL INLET

FUEL INLETUNION INTERNAL

SUPPLY PIPE

FUEL SPRAYINGINTO THE COMBUSTION

CHAMBER

DISTRIBUTOR

CENTRIFUGALWHEEL

LEAK CHECK PLUG




FUEL SYSTEM

START INJECTORS - GENERAL

Function

The two start injectors spray fuel into the combustionchamber during engine starting.

Position

- On the upper part of the turbine casing at 2 o'clock and10 o'clock

- They penetrate into the mixer unit.


- Type : simple injector

- Quantity : 2

- Ventilation : by air flow.

Main components

- Mounting flange

- Fuel inlet union

- Injector body

- Spraying jet.




START INJECTORS - GENERAL

Type :Simple injector

Quantity :2

Ventilation :By air flow

INJECTOR

IGNITERPLUG




FUEL SYSTEM

START INJECTORS - DESCRIPTION -OPERATION

Description

The injectors are mounted on the upper part of the turbinecasing. They penetrate into the combustion chamberthrough holes in the mixer unit.

They are secured by two bolts onto bosses with seals andspacers to prevent leaks and adjust the depth of penetrationinto the combustion chamber.

Injector components

- Injector body with mounting flange

- Fuel inlet (threaded to receive a union)

- Filter manifold

- Spacer and seals

- Nut

- Jet

- Shroud.

Operation

Starting

During starting the injectors are supplied with fuel.

The fuel is atomised and is ignited by the sparks from theigniter plugs. The flame thus produced, ignites the fuelsprayed by the centrifugal injection wheel.

Normal running

When the engine reaches self sustaining speed (approx.45 % N1) the fuel supply to the injectors is shut off.

P2 air is then blown through the injectors to avoidcarbonisation of the residual fuel.

It should be noted that ventilation is continuous duringengine running.




START INJECTORS - DESCRIPTION - OPERATION

P2

FILTERMANIFOLD

JET

SPACERS ANDSEALS

SHROUD

NUT

FUELINLET

MOUNTING FLANGE(mounting with two bolts)

INJECTOR


Starting

STARTINJECTORSUPPLY

STARTINJECTOR

VENTILATION

Normal running




FUEL SYSTEM

COMBUSTION CHAMBER DRAIN VALVE -GENERAL

Function

The valve drains overboard any unburnt fuel remaining inthe combustion chamber.

Position

- On the engine : screwed into the turbine casing lowerpart.


- Type : half-ball valve

- Setting : Closing obtained at about 40 % N1.

Main components

- Valve body

- Outlet union.




COMBUSTION CHAMBER DRAIN VALVE - GENERAL

VALVEBODY

Type :Half-ball valve

Setting :Closing obtained at

about ≈ 40 % N1

OUTLETUNION




FUEL SYSTEM

COMBUSTION CHAMBER DRAIN VALVE -DESCRIPTION - OPERATION

Description

The drain valve includes the following components :

- A threaded part to fix the valve on the combustionchamber

- A half ball valve mounted on a tension spring

- An outlet union which connects to the drain system

- A circlip which retains the valve in the body.

Operation

The valve has two positions : open and closed.

Open position

When the engine is not running and at the beginning ofstart, the valve is held open by the action of the tensionspring.

Any unburnt fuel in the combustion chamber will drainthrough the valve overboard to the drain system. Thisensures that no fuel accumulates in the combustion chamberwhich could cause starting problems (e.g. :overtemperature) .

Closed position

As the engine starts the combustion chamber pressureincreases. This pressure is felt on the upper surface of thehalf ball which moves down to close the drain.

The valve closes during the initial phase of starting for aspeed of about 40 % N1.




COMBUSTION CHAMBER DRAIN VALVE - DESCRIPTION - OPERATION

SEAL

HALF-BALLVALVE "OPEN" position

OPERATION

"CLOSED" position

Unburnt fuel

To drain system

P2 air pressure

DESCRIPTION

SPRING

OUTLETUNION

CIRCLIP

THREADS




FUEL SYSTEM

FUEL PIPES

Description

The fuel pipes ensure the circulation of fuel between thecomponents of the system.


- Type : rigid, stainless steel

- Unions : with integral olives.

Main pipes

- Fuel inlet union

- From FCU to overspeed and drain valve and to injectorelectro-valve

- From electro-valve to the two injectors

- From overspeed and drain valve to fuel inlet union

- From union to the wheel (internal pipe)

- From the pump to the overspeed and drain valve and thepurge valve (control system)

- Drains.

Note : The pipes may be different according to version.




FUEL PIPES

P2

P2

FCU TO OVERSPEEDAND DRAIN VALVE

AND TO START INJECTORELECTRO-VALVE

PUMP PRESSURE TOOVERSPEED AND DRAIN

VALVE AND PURGE VALVE

RETURNTO TANK

ELECTRO-VALVETO INJECTORS

DRAINSFUEL INLET

UNIONOVERSPEED AND DRAIN

VALVE TO FUEL INLET UNION



For training purposes only© Copyright - TURBOMECA - 2000 CONTROL SYSTEM

7-CONTROL SYSTEM

- Control system ............................................................... 7.2

• General ...................................................................... 7.2

• Description .................................................................................. 7.4

• Operation ................................................................... 7.6 à 7.33




CONTROL SYSTEM

Main components

- Fuel control unit

- Engine and systems

- Aircraft : various systems (control, indication, supply)

- Tachometer box - according to version.

CONTROL SYSTEM - GENERAL

Functions

The system is designed to adapt the engine to the aircraftpower requirements whilst remaining within defined limits.

The main functions are :

- Manual control

- Speed control

- Various limits

- Acceleration control

- Overspeed protection.


- Hydromechanical control

- Manual control.




CONTROL SYSTEM - GENERAL

TEST

G-BKXDSA 365 N

CONOCO

Management Aviation

F.C.U.

TACHOMETER BOX(according to version)

AIRCRAFT(various systems)

ENGINE(engine and systems)

MAIN FUNCTIONS

- Manual control

- Speed control

- Various limits

- Acceleration control

- Overspeed protection




CONTROL SYSTEM

CONTROL SYSTEM - DESCRIPTION

The complete system includes aircraft components, enginecomponents and the FCU.

Aircraft components

- Control devices (control lever and anticipator)

- Indicating devices (indicators, lights...)

Engine components

- Hydromechanical components :• Overspeed and drain valve

• Purge valve

• Start injector electro-valve

• Pressurising valve

• Start injectors

• Main injection system

- FCU components :• Power turbine speed governor• Gas generator speed governor• Acceleration control unit• Metering unit.




CONTROL SYSTEM - DESCRIPTION

ANTICIPATOR

POWER TURBINESPEED GOVERNOR

GAS GENERATORSPEED GOVERNOR

METERINGUNIT

PRESSURIZINGVALVE

INJECTIONWHEEL


CONTROLLEVER

PURGEVALVE

STARTINJECTORS


ACCELERATIONCONTROL UNIT




CONTROL SYSTEM

CONTROL SYSTEM - OPERATION (1)

Control - General

Installation configuration

The gas generator supplies power to the power turbinewhich is connected to the helicopter main rotor.

Installation requirements

- Aircraft rotor speed (NR) almost constant in all operatingconditions (because of the rotor efficiency) whatever theload applied

- Max torque limitation (imposed by the mechanicaltransmission and the helicopter main gearbox)

- Power turbine rotation speed (N2) within given limits(in fact almost constant, as it is connected to the rotor)

- Limitation of the gas generator rotation speed N1 :• Max N1 (maximum engine power)• Min N1 (to avoid critical speeds)

- Load sharing (equal sharing of loads between the 2engines)

- Protection against surge, flame-out, overtemp…

Adaptation to requirements

The control system ensures the engine adaptation to therequirements by metering the fuel flow CH sprayed intothe combustion chamber.

Thus, the gas generator adapts automatically to therequirements (N1 demand) to maintain constant powerturbine rotation speed N2 whilst keeping all the otherparameters within determined limits.

This adaptation is illustrated by :

- The diagram W/N2 which illustrates the power W, themax torque C and the rotation speeds N1 and N2

- The diagram N1/N2 which illustrates the N1/N2relationship.




CONTROL - GENERAL


N1

N2

Controlsystem

CH

INSTALLATION CONFIGURATIONAND REQUIREMENTS

N1

NR

Max

Min

Nominal N2

Operatingrange

W

N2

Max torque

N1 isospeeds

Max N1

Min N1

POWER W / N1, N2

N1 / N2

ADAPTATION TO REQUIREMENTS

TET

N2

CW

REQUIREMENTS

- NR- N2- Max torque- N1- W eng 1 = W eng 2- Protections




CONTROL SYSTEM


Principle of the control loop

The system meters the fuel flow in order to match theengine power to the requirements thus keeping powerturbine rotation speed constant. The control componentsare contained in the hydromechanical unit mounted on thefront face of the accessory gearbox.

Operation of the control loop

The power turbine governor compares the actual speed N2with a speed datum which varies with the collective pitch.It determines a speed datum (N1*) which is a function ofthe difference measured.

The gas generator governor compares the datum speed(N1*) and the actual speed (N1) and meters the fuel tomaintain the datum speed, thus matching the gas generatorto the conditions.

The acceleration control unit limits the transient fuel flowvariations in relation to P2 pressure so as to preventcompressor surge while permitting quick response times.

Static droop

In this type of control, the speed N1 is made inverselyproportional to N2. The relation N1/N2 illustrates thisproportionality and the N2 variation is called "static droop".

This droop ensures the stability of the system but it cannotbe tolerated as the helicopter rotor requires a given speed.

As the load mainly results from the collective pitch, alinkage with the governor is provided to compensate thestatic droop. Moreover, this linkage advances the phase ofdetection (this is why it is called anticipator) to reduce theresponse time.

The diagram illustrates the static droop line for differentcollective pitch angles (anticipator effect).

In the diagram : θ1 = low pitch, θ2 = medium pitch,θ3 = high pitch.

In operation, the points 1, 2 and 3 are obtained and thedroop is slighthy overcompensated ; ie : power turbinespeed (and therefore rotor speed) maintained almostconstant in all operating conditions.

In transient conditions, the power turbine speed varies, butthe governing system responds to regain the nominalspeed very quickly.

Note : the static droop is slightly overcompensated.




PRINCIPLE OF THE CONTROL LOOP


+

+

+

P2

N1*

N1

N2

N2*

Q

N1

N2

N1

N2

N2 N1

N2 N1

ACCELERATIONCONTROL UNIT

GAS GENERATORSPEED GOVERNOR

POWER TURBINESPEED GOVERNOR

GASGENERATOR

POWERTURBINE

MAIN GEARBOX

COLLECTIVEPITCH CONTROL θ

Static droop

Apparent static droop

WITHOUTANTICIPATOR

WITHANTICIPATOR

1

2

3 Apparent staticdroop line

Static droop linewithout anticipator

for different θ

θ2

θ3

θ1




CONTROL SYSTEM


Hydraulics of the FCU

The hydromechanical control unit operates with the fuel ashydraulic fluid and lubricant.

The illustration shows the entire fuel system.




HYDRAULICS OF THE FCU





CONTROL SYSTEM


Power turbine governor

This proportional type governor determines a datum signalaccording to the anticipator signal and the actual speed.

In stabilized conditions, the flyweight centrifugal forcebalances the datum spring force. The articulated lever is ina fixed position in front of the potentiometric jet. Thereduced pressure flows to the low pressure and a modulatedpressure is established in the chamber. The amplifierpiston (subjected to a reference pressure on one side and tothe modulated pressure on the other side) determines theN1 datum transmitted to the gas generator governor by alever and a plunger.

Transient conditions, the anticipator modifies the springtension while the centrifugal force changes. The articulatedlever pivots and moves in front of the potentiometric jetthus altering the leak and therefore changing the modulatedpressure. The amplifier piston then moves and, by meansof the lever and plunger, sets a new datum on the gasgenerator governor. The gas generator adapts itself to thenew condition until the balance is regained.

Operating envelope of control

The graph illustrates the N2 speed between max and minN1 ; the static droop is compensated, and slightlyovercompensated, by the action of the anticipator.




POWER TURBINE GOVERNOR


100% N2

N1

90

80

70

100%Max

Min

ANTICIPATOR

MAX N1STOP ARTICULATED

LEVERPOTENTIOMETRIC

JET

MIN N1STOP

N1 DATUMPLUNGER

AMPLIFIERPISTON

N2 DATUMSPRING

N2 SPEEDDETECTOR(flyweight)

Low pressure(≈ 1 b)

Modulated pressure N2(≈ 2.8 b)

Reduced pressure(≈ 4 b)

Operating envelope of control

Power turbinenominal speed

Static droop lines fordifferent collective

pitch positions




CONTROL SYSTEM


Gas generator governor

This integral type governor controls the datum speeddemanded by the power turbine governor. It achieves thiscontrol by metering the fuel flow.

In stabilized conditions, the flyweight centrifugal forcebalances the force of the datum spring. The lever is in afixed position and the valve determines a given modulatedpressure. The working piston controls a given position ofthe metering needle which meters the fuel flow to obtainthe required rotation speed. The system is "in balance".

In transient conditions, we have seen that the powerturbine governor determines a new datum which upsets thebalance. The lever moves, the leak varies and consequentlythe modulated pressure. The working piston moves themetering needle until the new N1 datum is obtained. Thegas generator speed increases or decreases, thus regulatingengine output power to match the load and obtain aconstant power turbine speed.




GAS GENERATOR GOVERNOR


t

t

C

N2

Q

N1

t

t

N1 DATUMSPRING

ARTICULATEDLEVER

N1 SPEEDDETECTOR(flyweight)

DAMPINGDEVICE

THERMALCOMPENSATOR

POTENTIOMETRICJET

WORKINGPISTON

METERINGNEEDLE

Low pressure(≈ 1 b)

Modulated pressure N1(≈ 3 b)

Reduced pressure(≈ 4 b)

N1 SPEED (Increase ordecrease to match the load

variations)

FUEL FLOW Q (Variationcontrolled by the governor)

N2 SPEED (Transient variationand quick return to nominal speed)

LOAD C (Eg : collective pitch)

VARIATION OF THE MAINPARAMETERS IN TIME




CONTROL SYSTEM


Acceleration control unit

It limits fuel flow increase in transient conditions, in orderto prevent compressor surge during acceleration.

In stabilized conditions, there is a gap between the forkand the metering valve. The position of the metering valveis determined by the working piston.

In load increase transient conditions, the governor"responds" and the working piston moves rapidly. Underthe action of its spring, the metering needle opens until itstops against the fork. This displacement represents whatis called "instant flow increase" initiating the acceleration.Then the subsequent increase in P2 pressure causes thedeformation of the capsule which permits further openingof the metering needle until it comes into contact with theworking piston.




ACCELERATION CONTROL UNIT


x

P0 P2

P0

Q

P2

Maxi

Mini

X

Min flow stop of theacceleration control unit

Max flow stop of theacceleration control unit

Max flow for a determined P2pressure (lever mechanism position)

ACCELERATION CURVE(Fuel flow Q as a function of compressor pressure P2)

"X" instant flow increase = distance between the metering valve position

and fork position

BAROSTATICDEVICE

ACCELERATIONCAPSULE

LEVERMECHANISM

CAMWORKINGPISTON

DIAGRAM OF THE MECHANISM

ACCELERATIONCAPSULE

GAP (x) CAMWORKINGPISTON

FUEL METERINGNEEDLE

LEVERMECHANISM

METERINGNEEDLE




CONTROL SYSTEM


Deceleration control unit

In some versions, a deceleration control unit (or min flowlimiter) is included in the metering unit to prevent flame-out during deceleration.

In load decrease transient conditions, the closing of themetering needle is limited by a mechanical stop.

This mechanical stop is controlled by a diaphragm subjectedto P2 pressure.

The stop withdraws as the P2 pressure decreases in orderto prevent engine flame-out during rapid deceleration.




DECELERATION CONTROL UNIT


P2

P0P2

Q

P2

DECELERATION CURVE(Q as a function of P2)

DECELERATIONCONTROL UNIT

Min flow curveas a function of P2 pressure




CONTROL SYSTEM


Metering unit

Metering needle

The metering needle is a profiled needle which moves ina calibrated orifice.

The fuel under pump pressure flows through the passagedetermined by the metering needle sliding in the orifice.

Constant ∆P valve

To obtain a fuel flow solely depending upon the meteringneedle position, this valve keeps a constant pressuredifference across the metering needle. It consists of adiaphragm subjected metering needle pressure variation.Any variation of pressure difference (∆P) is sensed by thisvalve which returns more or less fuel to the inlet of thepump. In fact, the pump always supplies a flow higher thanthe engine requirements and the excess fuel is returned tothe inlet.

The ∆P transient variations are due to the pump pressurevariations, to the downstream pressure variations and ofcourse to the displacement of the metering valve.

For example : when the metering needle opens, the pressuredifference decreases, the valve diaphragm senses this andmoves to close the return. More fuel is admitted to theengine, the upstream pressure increases and the nominal∆P is regained.

The graphs below illustrate the valve operation

Graph of fuel flow (Q) as a function of metering needleposition (S) : each position corresponds to a fuel flow andeach displacement ∆S corresponds to a proportional flowvariation ∆Q.

Graph of fuel flow (Q) in relation to the pressuredifference (∆P) : in transient conditions, the ∆P varies, butthe valve operates to return it to its initial value with a slightstatic droop.




METERING UNIT


FUELRETURN

FUELINLET

FUELOUTLET

METERINGNEEDLE

CONSTANT∆P VALVE

∆P

Q

Max

Min

Q AS A FUNCTION OF ∆P

∆S

∆Q

Q

S

Q AS A FUNCTION OFNEEDLE POSITIONS (S)




CONTROL SYSTEM


Limits of gas generator speeds

The gas generator rotation speed varies (to adapt theengine to changing conditions) between two extremelimits represented by adjustable mechanical stops.

Max speed

It is automatically limited by a fixed adjustable stop whichrepresents the max operating rating.

TAKE-OFF - Max take-off power in the case of a singleengine (in fact, this rating is given at avalue slightly lower than the mechanicalstop and the engine must be operated notto overcome it).

MAX CONTINGENCY - Max power in the case ofengine failure during take-off or landing of a twinengine helicopter. In someversions an extreme ratingcalled super contingencypower is used.

The effect of fuel temperature on the speed (variation offuel viscosity changing the balance point of thehydromechanical governor) is compensated by the capsulein order to obtain speed invariability (especially max N1).A slight max N1 variation is however introduced butwithin given limits.

Min governed speed

It is limited by a fixed adjustable mechanical stop to avoidlow speeds corresponding to critical ratings. In operation,this limit is practically never reached because, even at zerotorque, the power to drive the compressor requires a higherspeed. Therefore, the stop is only a safety measure and itis only adjusted on the FCU test rig.

Limits of fuel flow

Fuel flow variation in transient conditions is limited by theacceleration control unit to obtain an optimum accelerationwithout compressor surge. The acceleration rate determinesthe response time. The slope of acceleration is onlyadjustable on the test rig.

The min fuel flow (limit to prevent flame-out) is limited bya mechanical stop on the metering needle. In some versions,this stop is variable with P2 pressure ; it is also called thedeceleration control unit.

The max fuel flow is determined by the full opening of themetering needle for a given pressure difference ∆P. It is afactory adjustment which represents a sort of powerlimitation.

In manual control (emergency control), the max fuel flowis limited at a lower value to avoid exceeding of the limits.




LIMITS


N2

N1

90

80

70

100%

100%

N1

t°

Q

P2

Max.

Min.

N1 LIMITS

N1 max as a function offuel temperature

N1 thermallimit

N1limit toensure power

Metering unit max Q

Manual control max Q(emergency)

Metering unit min Q(with decelerationcontrol unit)

Metering unit min Q(without decelerationcontrol unit)

FUEL FLOW LIMITS (Q)




CONTROL SYSTEM


Limit of torque

A max torque limit is required by the mechanicaltransmission. The control system does not ensure a torquelimit and the operating instructions should be observed toprevent any overtorque. The flight manual indicates thetorque limits : also see chapter "indication" of this manualfor details of the torque measuring system.

Power turbine overspeed safety system

This safety system is not included in the control unit but isoften mentioned among the functions of the engine controlsystem.

The overspeed safety system is designed mainly to takeinto account the case of shaft failure resulting in a verysudden acceleration which cannot be contained by thespeed governor. The system includes a speed detector, anelectronic unit and the overspeed and drain valve of thefuel system.

It is installed on some versions : twin engine configurationsmainly (see details of the system in electric system chapter).




LIMIT OF TORQUE - POWER TURBINE OVERSPEED SAFETY SYSTEMCONTROL SYSTEM - OPERATION (10)

TEST

Q

C


TACHOMETERBOX

N2DETECTOR

TORQUEINDICATOR




CONTROL SYSTEM


Control system performance

As regards the operation, the control system performancedetermines some flight characteristics.

The following can be distinguished :

- The response time

- The static and dynamic power turbine speed variations

- The max speed of the gas generator.

Response time

It can be defined as the time required to regain powerturbine nominal speed in transient conditions. The responsetime is closely associated to the rate of acceleration of thegas generator.

A check of the response time can be made by recordingparameters during a load application. It is approx. 4seconds between N1 min and max in standard conditions.

Dynamic variation of power turbine speed

It is the transient speed variation occurring during a loadvariation. The amplitude of this variation can be observedon the rotor speed indicator ; it is related to the othercharacteristics.

Static variation of power turbine speed

It can be defined as the speed variation at different ratings.This static variation (a static droop which is slightlyovercompensated) can be checked by noting NR speed atdifferent operating points (eg : ground fine pitch and cruisepitch). With the increase of power, the NR increasesslightly within given limits.

Max available speed of the gas generator

It is the max speed that can be obtained from the gasgenerator (take-off on single engine and max contingencyon twin engine). This rating can be checked on a loadapplication, noting the max speed obtained when the rotorspeed starts decreasing.




CONTROL SYSTEM PERFORMANCE


≈ 4 sec

≈ 4 sec

100% N2

N1Max

90

80

70Min

N2

100%

RESPONSE TIME AND DYNAMICVARIATION OF THE POWER

TURBINE SPEED N2STATIC VARIATION OF N2POWER TURBINE SPEED

Time




CONTROL SYSTEM


Twin-engine configuration

Principle of load sharing

In normal conditions, the helicopter rotor is driven by thetwo power turbines and therefore :

NR = k N2 eng 1 = k N2 eng 2

The speed signals received by the two power turbinegovernors being identical (as well as the signals from thecollective pitch), they determine identical datum signalssent to the two gas generator governors which meter fuelflow to keep them constant.

As the power is closely related to the N1 speed and as theefficiency does not vary much from one power turbine toanother, a fairly good load sharing is obtained.

Operation on one engine

In this case, the engine remaining in operation supplies thepower while the other one is disconnected by the freewheel.

The limit of the operative engine is represented by the maxcontingency rating automatically limited by the fuel controlunit. This rating, determined for engine failure duringtake-off or landing, has a limited duration : 2 mn 30 s.




TWIN-ENGINE CONFIGURATION


QN2

NR=k.N2 eng1=k.N2 eng2

N1

N1*N2*

N

C

t4

N1

NRN2

(1&2)

Tq1&Tq2

t4

N1 Max

POWER TURBINEGOVERNOR

TRIM

COLLECTIVEPITCH

MAINGEARBOX

REDUCTIONGEARBOX

POWERTURBINE

GASGENERATOR

FREE WHEEL





CONTROL SYSTEM


Control system loop (1)

"Image" of load increase

t = 0 - "Start" Collective pitch movement

θ - The pitch increases

W1 > W - The resisting torque becomes higher thanthe drive torque

N2 - The power turbine rotation speed decreases

G - The N2 governor detects the 2 signals, andsends a datum increase to the N1 governor :the N1 governor increases the fuel flow Q

Q - Instantaneous flow step

P2 - The compressor discharge pressure increases

AC - The acceleration control unit enables theacceleration to continue

Combustion - The flow Q increases in the combustionchamber

N1 - increases, the output power W increases, the N2speed stops decreasing and returns to its nominalvalue when the equilibrium between torques W1 =W is achieved.

t = 4 seconds End of transient

Evolution of parameters

θ - Collective pitchSudden increase from min. to max. almost instantly

N2 - Power turbine speedTransient decrease and rapid return to nominalspeed after a slight overshoot, and a slightovercompensation of the static droop

N1 - Gas generator speedSpeed increase and stabilisation after a slightovershoot

t - Time in seconds




CONTROL SYSTEM LOOP (1)


t = 0

t = 4

W = W 1

N2

W

N1

W > W1

N2

Q

P2

AC

Q

NR

G

N2

N1

32 2

31

1 N2

2

3

1

2

31

t

t

t

N1

N2

Combustion

Evolution of parameters during a load increase"Image" of a load increase




CONTROL SYSTEM


Control system loop (2)

"Image" of a load decrease

t = 0 - "Start" Collective pitch movement

θ - The pitch decreases

W1 < W - The resisting torque becomes lower than thedrive torque

N2 - The power turbine rotation speed increases

G - The governor detects the N2 increase anddecreases the fuel flow Q

DC - The deceleration controller limits the minfuel flow (if needs be)

Combustion - The flow Q decreases in the combustionchamber

N1 - decreases, the output power W decreases, the N2speed returns to its nominal value.

t = 4 seconds End of transient

Evolution of parameters

θ - Collective pitchRapid decrease of pitch

N2 - Power turbine speedTransient increase and return to nominal speed(within the static droop)

N1 - Gas generator speedSpeed decrease and stabilisation

t - Time in seconds




CONTROL SYSTEM LOOP (2)


N132

32

11

N2

2

3

1

2

31

t

t

t

N1

N2

t = 0

t = 4

W = W

N2

W

N1

W < W1

N2

G

Q

P2

DC

Q

NR

1

Combustion

N2

"Image" of a load decrease Evolution of parameters during a load decrease



For training purposes only© Copyright - TURBOMECA - 2000 CONTROL AND INDICATION

8-CONTROL AND INDICATION

- Manual control system .................................................. 8.2- Indicating system ........................................................... 8.6- Speed indication............................................................. 8.8- Tachometer transmitters............................................... 8.10- Speed probes (1K, 1S, 1E versions).............................. 8.14- Gas temperature indication .......................................... 8.16- Thermocouple probes.................................................... 8.18- Thermocouple junction box (1S version) .................... 8.20- Torque indication........................................................... 8.22- Torquemeter ................................................................... 8.24- Torque transmitter ........................................................ 8.26- Miscellaneous indications ............................................. 8.28 to 8.35




CONTROL AND INDICATION

MANUAL CONTROL SYSTEM - GENERAL

Function

The system ensures the manual control of the engine.

Main components

Fuel flow control

This lever is used to start and stop the engine and to controlthe engine power manually in the event of an FCU failure.

Anticipator control

This lever links the collective pitch to the fuel control unit.

Note : As regards the electrical controls refer to chaptersstarting and electrical.




MANUAL CONTROL SYSTEM - GENERAL

FCU

CONTROLLEVER

ELECTRICAL CONTROLS

COLLECTIVE PITCHANTICIPATOR CONTROL

FUEL FLOW CONTROL





MANUAL CONTROL SYSTEM - MECHANICALCONTROLS

Function

The control lever is used to control engine start and shut-down. It can also be used for manual engine power control ;particularly in the event of a failure of the control system.

The collective pitch lever inputs signals to the anticipatorduring flight.

Description

This system includes the control lever with its mechanicallinkage and the collective pitch lever with its mechanicallinkage.

Operation

This part only mentions the position of the mechanicalcontrol lever. See chapter 6 and the aircraft manual formore details.

Stop position. Cam in contact, the two valves are closed.

Start position. Lever at approx 20°, slight opening of themain valve.

Acceleration range. Lever moved from "idle" position to"flight" position ; progressive opening of the main valve,and after a certain angle the cam releases its contact.

Flight position. Lever in the "flight" notch : main valvefully open.

Manual range (+). After overriding the lock, the lever canbe moved forward in the + range : increase of fuel flow.

Manual range (-). Lever moved rearward in the (-) range :decrease of fuel flow down to shut-down after overridingthe lock.




MANUAL CONTROL SYSTEM - MECHANICAL CONTROLS

CONTROLLEVER

ENGINEHELICOPTER

FUELCONTROL

UNIT

COLLECTIVE PITCH

90°

52°

5°45°

0°110°





INDICATING SYSTEM

Functions

The indicating system provides the following functions :

- It allows the pilot to check that the engine is operatingwithin determined limits

- It indicates faults or abnormal changes of parameters

- It allows the checking of certain operating phases.

Note : In fact there are operating parameters (e.g. : N1and torque) and monitoring parameters (e.g. N2,t4, oil temperature and pressure).

Miscellaneous indications

- N1 gas generator rotation speed

- N2 power turbine rotation speed

- t4 gas temperature

- Engine torque

- Oil system (refer to Chapter "OIL SYSTEM")

- Indicating lights

- Cycle counter.




INDICATING SYSTEM

ENGINE TORQUEINDICATION

FUNCTIONS

t4 TEMPERATUREINDICATION

N2 SPEEDINDICATION

N1 SPEEDINDICATION

LUBRICATING SYSTEMINDICATION

MISCELLANEOUSINDICATIONS

- To ensure that the engine operates within determined limits

- To indicate fault or abnormal changes of parameters

- To check certain operating phases





SPEED INDICATION

Function

This system measures the rotation speeds of the gasgenerator (N1) and the power turbine (N2).


- Type : tachometer transmitter or phonic wheel accordingto version

- Transmitter signals : frequency proportional to therotation speed.

Main components

- N1 speed transmitter

- N2 speed transmitter

- Electrical harnesses for connection to the indicators.

Description

One or two tachometer generators (N2 optional) linked toone or two indicators.

Operation

N1 is an operating parameter as it reflects the engine powerand serves to determine the limit ratings.

The N2 signal is used for the N2 indication (associatedwith the NR indication).




SPEED INDICATION

N1 INDICATOR

N2 INDICATOR

ACCESSORY GEARBOX REAR FACE





TACHOMETER TRANSMITTERS -GENERAL

Function

To measure the rotating assembly's rotation speed.

Position

- Rear face of the accessory gearbox :• N1 on the right side• N2 on the left side according to version.


- Quantity : 2 identical N1 and N2 transmitters(interchangeable)

- Type : 3-phase permanent magnet generator.

Main components

- Body

- Electrical plug.




TACHOMETER TRANSMITTERS - GENERAL

Number :2 identical

transmitters

Type :3 phase, permanentmagnet generator

BODY

ELECTRICAL PLUG





Operation N2

The permanent magnet rotation in front of the three coilsinduces an alternating current.

The frequency of this current is proportional to the rotationspeed.

In normal operation, there is a link between the rotor speedNR and the power turbine speed N2. The same instrumentcan be used to indicate the NR and N2 speeds (the two N2speeds in a twin engine configuration).

N1 & N2 TACHOMETER TRANSMITTERS -DESCRIPTION - OPERATION

Description

The assembly consists of :

- A tachometer generator which has a mechanically drivenpermanent magnet as rotor. It delivers an electricalsignal which is a three-phase alternating current with afrequency proportional to the speed

- An asynchronous motor which receives the transmittersignal and displays the speed on a graduated dial.

Operation N1

The permanent magnet rotation in front of the three coilsinduces an alternating current.

The frequency of this current is proportional to the rotationspeed.




N1 & N2 TACHOMETER TRANSMITTERS - DESCRIPTION - OPERATION

STATORINDICATOR





SPEED PROBES (1K, 1S, 1E VERSIONS)

Description - Operation

On the versions 1E, 1K and 1S the speed indication isachieved using phonic wheels and speed probes.

Description

The system consists of a toothed wheel, called a phonicwheel, rotating in front of an electro-magnetic pick-upwhich is connected to an indicator.

The phonic wheel for N1 indication is fitted on the startergenerator drive shaft. The N1 probe is mounted on theaccessory gearbox casing right hand side.

The phonic wheel for N2 indication is fitted on the rear ofthe intermediate gear of the reduction gearbox and the N2probe is mounted in the bottom of the rear drive shaftcasing.

Operation

The passage of the teeth in front of the electro-magneticprobe induces an alternating current in the probe windings.This current has a frequency proportional to the speed andthe number of teeth :

nd x NF =

60

Where : nd = N° of teeth ; N = rotation speed in RPM ;F = frequency

The signal from the probe is transmitted to the cockpitindicator which transforms it into an indication which maybe analog, digital or both.




SPEED PROBES (1K, 1S, 1E VERSIONS)

F = nd x N60

TO THEINDICATOR

SPEEDPROBE

PHONICWHEEL

PHONICWHEEL

PHONIC WHEEL(starter generator

drive shaft)

ELECTRO-MAGNETICPROBE

INDICATOR

OPERATIONDESCRIPTION

N2 SPEED PROBE

N1 SPEED PROBE

N1 SPEEDPROBE

N2 SPEEDPROBE

ELECTRICALCONNECTOR

ELECTRICALCONNECTOR

REAR OF THEINTERMEDIATE GEAROF THE REDUCTION

GEARBOX





GAS TEMPERATURE INDICATION

FunctionThis system provides an indication of the gas temperature(t4) at the gas generator turbine outlet.

Position- All the system components are located on the engine

except the t4 indicator.

Main characteristics- Type : pyrometric device with thermocouple probes- Indication : degrees Celsius.

Main components- Thermocouple probes- Thermocouple junction box (1S version)- Harness- Indicator.

General operationThe gas temperature (t4) is an operating parameter,particularly during engine starting.

As it would be difficult to measure the turbine inlettemperature, the gas generator outlet temperature ismeasured.

Measurement is made by thermocouples connected to anindicator.

The system produces a voltage proportional to thetemperature of a junction of two dissimilar metals. Thevoltage produced is measured by a galvanometer indicatorwhich is graduated in degrees Celsius.

THERMOCOUPLE PROBES -FUNCTIONAL DESCRIPTION


The thermocouple probes are identical. They are positionedto give a homogeneous measurement.

Each probe contains a hot junction (Chromel and Alumelwires soldered together).

The thermocouples are connected in parallel either to theaircraft indicator directly or through an amplifier providinganalog and digital outputs.

A thermocouple produces an electromotive force which isproportional to the temperature difference between the hotand the cold junction.

The electromotive force is delivered to the t4 indicator(galvanometer graduated in degrees Celsius).

The probes are wired in parallel. The reading obtained isan average temperature.





t4 TEMPERATUREINDICATION

THERMOCOUPLE PROBES

t°

THERMOCOUPLEJUNCTION BOX

(1S version)

THERMOCOUPLEJUNCTION BOX

(1S version)

INDICATOR ALUMEL

CHROMEL HOTJUNCTION

COLDJUNCTION





THERMOCOUPLE PROBES - GENERAL

Function

The thermocouple probes measure the gas temperature(t4) at the gas generator outlet.

Position

- Around the rear part of the combustion chamber casing.


- Type : Chromel-Alumel

- Number : 3 probes

- Alumel wire : magnetic, negative polarity

- Chromel wire : non magnetic, positive polarity

- Connection : in parallel.

Main components

- For each probe :• Probe (sheath and thermocouple)• Mounting nut• Cable.




THERMOCOUPLE PROBES - GENERAL

CABLE

MOUNTINGNUT

PROBEType :

Chromel - Alumel

Number :3 probes

Alumel wire :Magnetic, negative polarity

Chromel wire :Non magnetic, positive polarity

Connection :In parallel





THERMOCOUPLE JUNCTION BOX (1SVERSION)

Function

The junction box forms the interface between thethermocouples and the indicator.

Position

- On a bracket at the upper part of the power turbine.


- Type : box with connectors.

Main components

- Junction box

- Mounting flange

- Connectors.

Description

It includes the following connectors :

- Thermocouple connectors

- Indicator connectors.

The connection system of chromel and alumel wires is inthe box.

Operation

The t4 junction box provides a connection between thethermocouple probes and the aircraft indicator.




THERMOCOUPLE JUNCTION BOX (1S VERSION)

THERMOCOUPLECONNECTORS

THERMOCOUPLECONNECTOR

Type :Box with

connectors

INDICATORCONNECTOR

JUNCTIONBOX

THERMOCOUPLE





TORQUE INDICATION

Function

To provide an indication of the engine torque measured atthe reduction gearbox intermediate gear.

Position

- All the system components are located on the engineexcept the torque indicator.


- Type : hydraulic torquemeter

Main components

- Torquemeter piston

- Electrical transmitter

- Torque indicator.

Description

Refer to the following pages.

General operation

The reaction torque is transformed into axial force on thereduction gear intermediate pinion. The force is transmittedto a piston which determines an oil leak modulating apressure representative of the torque.

The pressure is transformed into electrical current suppliedto the indicator by a transmitter.




TORQUE INDICATION

TORQUE MEASUREMENT

- Hydraulic torquemeter

- Electrical transmitter

- Torque indicator

INDICATOR

FILTER

TRANSMITTER

LEAK

TORQUEMETERPISTON

RESTRICTOR

TO ENGINELUBRICATION

OIL PUMP





TORQUEMETER

Function

To measure the torque transmitted to the output drive.

Position

- In the intermediate gear of the reduction gearbox.


- Type : hydraulic, using oil from the engine lubricationsystem.

Description

The torquemeter piston is fitted into the hub of theintermediate gear of the reduction gearbox on three stopbearings.

The head of the piston fits into a cavity in the reductiongearbox front casing. An oil tube passes through thehollow shaft of the piston and forms a passage between thepiston and the tube base. Oil from the torquemeter systemcan pass through this passage.

Operation

The torque on the output shaft is transmitted to the reductiongearbox. The intermediate gear, which has helical teeth,transmits the axial force to the piston, via the stop bearings.The movement of the intermediate gear/piston assemblyvaries the oil flow between the piston and the tube base.This pressure variation is felt by the torque transmitter.




TORQUEMETER - DESCRIPTION - OPERATION

Type :Hydraulic

INTERMEDIATEGEAR

TORQUEMETERPISTON

STOPBEARINGS

LUBRICATIONTUBE

OIL INLET(pressure modulated

by the piston)

REDUCTIONGEARBOX

CASING

OIL FLOWVARIATION





TORQUE TRANSMITTER

Function

The transmitter transforms the hydraulic signal (modulatedpressure from the piston) into an electrical signal andtransmits it to the indicator.

Position

- Rear right hand side of the accessory gearbox.


- Type : inductive or resistive, according to version

- Adjusted and matched to the reduction gearbox.

Main components

- Transmitter.

Description

The system includes :

- A calibrated orifice

- A transmitter

- A pressure tapping point.

Note : The torque transmitter or the indicator (accordingto version) is adjusted and matched to the reductiongearbox.




TORQUE TRANSMITTER

INDICATOR

TORQUEMETER PISTONMODULATED PRESSURE

TRANSMITTER

PUMPPRESSURE

RESTRICTOR

PRESSURETAPPING

Type :Inductive or resistive(according to version)

Note : The torque transmitter or the indicator (according to version) is adjusted and matched to the reduction gearbox.





MISCELLANEOUS INDICATIONS -GENERAL

Function

The miscellaneous indications provide information aboutthe engine operation

Position

- Engine

- Aircraft.


- Electrical measurement circuit directly connected toindicators.

Main components

- Sensors and engine accessories (refer to correspondingchapters for more information)

- Instruments and indicators on the instrument panel :• Indicators• Instruments.




MISCELLANEOUS INDICATIONS - GENERAL

Firewall

ENGINEAIRCRAFT

SENSORS AND ACCESSORIES

ENGINE

LIGHTS AND INSTRUMENTS





MISCELLANEOUS INDICATIONS -INDICATORS

There are several indicators which give information aboutthe engine operation. These pages summarize the variouslights which have already been dealt with in other chapters.

Position

- On the instrument panel.


- Indicating lights directly connected to engine sensors

- Indications provided by the aircraft.

Lights directly connected to the engine sensors

- Low oil pressure

- Electrical magnetic plug

- Bleed valve position.

FUELINDICATING

OILINDICATING

AIRINDICATING

POWERINDICATOR

OVERSPEEDINDICATING

FIREINDICATING

"LIFE"INDICATOR

- "Real time" fuel flow indicator- Total fuel flow indicator- Min fuel pressure indicator

- Max oil temperature indication

- Compressor bleed valve positionindication(See chapter "air system")

- Air intake anti-icing indication- Air intake sand filter condition

indicator

- Power loss indication(For example N2 differentialindicator in a twin engineconfiguration)

- Power difference indication(For example torque differentialindicator in a twin engineconfiguration)

- Overspeed arming indicator(See chapter "electric system")

- Overtemperature detection in givenengine area(See chapter "power plantinstallation")

- Example : PSU control box onARRIEL 1M(See chapter "electric system")

INDICATIONS ACCORDING TO AIRCRAFT TYPE




MISCELLANEOUS INDICATIONS - INDICATORS

HELICOPTER

ENGINE

+ 28 V

Low oil pressure

Bleed valve position

Electrical magnetic plugCircuit breaker

INDICATING :

• Fuel

• Oil

• Air

• Power

• Overspeed

• Fire

• "Life"





MISCELLANEOUS INDICATIONS - N1 INDICATOR (1S VERSION)

FunctionThe two N1 indicators provide an analog (needle on a dial)and digital indication. Each indicator has a P0 pressuresensor and receives temperature t0 and N1 signals.

Position- Instrument panel.

Main characteristics- Analog indicator graduated in percent

- Digital display unit in percent

- Bleed valve and operating mode indicators.

Main components- Sensors

- Indicator.

OperationIn normal operation (twin engine), the system operates asa normal tachometer system. A connection between thetwo indicators allows passage to the OEI (One EngineInoperative) mode when one of the two engines fails.

The change to OEI mode is automatic when one N1 islower than 66 % and the other one higher than 94 %.

In this configuration, the max speeds indicated are :

- Max contingency : 101.7 %- Intermediate contingency : 100 %- Max continuous : 99 %.

The indicator has an integrated microcalculator whichallows indication of the OEI ratings corrected by flightconditions :

- Normal mode: analog N = digital N = actual N- OEI mode : analog N = digital N = corrected N

ƒ(Zp - t0)- Test : analog N indicates max contingency :

i.e. 101.7 %digital N indicates actual max contingencyƒ(Zp and t0).

In normal operating conditions, the analog indication isthe same as the digital indication, but the available maxcontingency rating (depending upon the conditions) canbe read by actuating the test button.

This indication must be compared to a table located in thecockpit which shows the ratings as a function of Zp and t0.

About 2 seconds after actuating the button, the digitalindicator displays 188.8 and then returns to the normalindication.

The OEI operating mode is indicated by the flashing of thedecimal point and by the visual and audible warningsystem.

The system also ensures :

- The cut-out of the cabin heating- The cut-out of the EAPS if anti-icing is not selected.




- 1S VERSION -

MISCELLANEOUS INDICATIONS - N1 INDICATOR

BV

100

9896

9575

55

35

15

T

N1%N1

t0≈ 20°

102.7 102.7 102.6 102.5 102.3 102.1 101.8

102.7 102.6 102.5 102.4 102.2 102.0 101.7

102.7 102.6 102.4 102.3 102.1 101.9 101.7

102.7 102.4 102.3 102.2 102.0 101.8

102.6 102.3 102.2 102.1 101.9

102.4 102.2 102.1 102.0

102.1 102.1 102.0

102.0 102.0

-3.5 +10 +25 +30 +35 +40 +45 +50-1

+1

+3

+5

+7

+9

+11

+13

+15

Zp (ft x 1000)

t0 (°C)

N1 INDICATOR

EXAMPLE OF COMPARISONTABLE

EXAMPLE OF LIMITGRAPH

MAX TWIN ENGINERATING (100%)

MAX AUTHORIZEDSPEED AT GIVEN

RATING (ZP/t0)

MAX INDICATEDSPEED : i.e. 101.7%

COMPRESSORBLEED VALVE

INDICATOR LIGHT

MAX ONE ENGINERATING(101.7%)

FLASHESWHEN

INDICATINGOEI RATING

TEST





MISCELLANEOUS INDICATIONS -CYCLE COUNTER

Function

The cycle counter automatically carries out the calculationsstated in the maintenance manual.

Main components

- Tachometer box with failure indicator

- Display unit with N1 and N2 cycle displays

- Electrical connectors.

Note : In the 1E and 1S version, a same box ensures thetwo functions of N2 overspeed protection andcycle counter.

Operation

The input signal is the N1 speed supplied by a pick-up orby the tachometer generator.

With this information, the system converts the engineactual operating cycles into "reference cycles" and displaysthe result.

For the power turbine, the relationship is : 1 cycle = 1 start.

It is then possible to calculate the number of cycles of lifelimited parts.

The electronic box corresponding to an engine variant canperform some (or all) of the following functions :

- Count engine operating cycles

- Control electro-pneumatic compressor bleed valve

- Protect against power turbine overspeed

- Monitor the power turbine.




MISCELLANEOUS INDICATIONS - CYCLE COUNTER

DISPLAYUNIT

FAILUREINDICATOR

N1, N2 AND 24 VINPUTN1 AND N2

CYCLE DISPLAYS



For training purposes only© Copyright - TURBOMECA - 2000 STARTING

9-STARTING

- Starting system ............................................................. 9.2

- Starter ............................................................................. 9.10

- Ignition system .............................................................. 9.16

- Ignition units .................................................................. 9.18

- Igniter plugs ................................................................... 9.22

- Ignition cables ................................................................ 9.26 to 9.27




STARTING

Main components

- Starter (cranking)

- Ignition units and igniter plugs

- Fuel system (supply, metering and delivery)

- Indicating and control system :• Electrical system• Instruments.

STARTING SYSTEM - GENERAL

Function

The starting system ensures starting (on the ground and inflight) and ventilation of the engine. It includes the followingfunctions : cranking, fuel supply and ignition.

Position

All the starting accessories are installed on the engine.Indicating and control components are supplied by theaircraft manufacturer.


- Starting envelope : according to version

- Start duration : between 25 and 30 sec

- Max ventilation time : less than 15 sec

- Stabilisation time before shut-down : 60 sec

- Run-down time : more than 30 sec from 30 to 0 % N1.




STARTING SYSTEM - GENERAL

CRANKING

FUEL SUPPLY ANDDISTRIBUTION

IGNITIONUNITS

IGNITERPLUGS

IGNITION

START CONTROLAND INDICATING

STARTER




STARTING

STARTING SYSTEM - DESCRIPTION

Starter

The starter is electrically supplied with direct current fromthe batteries through the aircraft electrical system.

During starting, the starter drives the gas generator rotatingassembly through the accessory drive train.

At the end of starting, the electrical supply to the starter iscut.

The starter is installed on the front face of the gearboxcasing.

Ignition unit

The ignition units are of high energy type. They transformthe direct current voltage provided by the aircraft systeminto high energy voltage required for the igniter plugoperation.

The ignition units are located at the right side of the axialcompressor casing.

Igniter plugs

The engine has two igniter plugs which ignite the air fuelmixture sprayed by the start injectors.

The igniter plugs are installed close to the start injectorsand are connected to the ignition units by two cables.

Fuel system

The fuel system supplies fuel to the start and main injectors.

Refer to "FUEL SYSTEM" chapter for more details.

Control and indicating system

The control system includes :

- The cockpit components (fuses or circuit-breakers,ventilation and start push-buttons, the manual controllever)

- The supply (28 V battery)

- The accessory relay (to electrically supply the startingaccessories)

- The starter contactor

- The overspeed box (twin engine only).




STARTING SYSTEM - DESCRIPTION

VENTILATIONPUSH-BUTTON

STARTPUSH-BUTTON

CIRCUITBREAKER

STARTERCONTACTOR

ACCESSORYRELAY

OVERSPEEDBOX

STARTER-GENERATOR

IGNITIONUNITS





STARTING

STARTING SYSTEM - OPERATION (1)

This section deals with operating sequences associatedwith the starting system : start, stop and ventilation

Starting cycle

The starting cycle is characterised by the evolution of theengine parameters, especially the rotation speed and thegas temperature.

The main points of the starting cycle are :

- Start selection

- Self-sustaining speed (de-energisation of the starter andignition units)

- End of start (stabilisation at min power).

Shut-down cycle

This cycle comprises the following points :

- Stabilisation at idle speed

- Stop selection

- Run-down and stop.

Ventilation cycle

A ventilation consists of cranking the rotating assemblywithout supplying fuel or ignition (dry ventilation). It isused for cooling the engine or for maintenance procedures.

The ventilation cycle comprises the following phases :

- Ventilation

- Cranking of the rotating assembly

- End of ventilation and run-down.

Note : Ventilation time is limited to 15 sec. to avoidoverheating of the starter motor.





N1

≈ 200°C(injection wheelsupply)

Time

N1 speed

Time

Self-sustainingspeed 45%

Selection

t4 gastemperature

Stop selection

Run-down

SHUT-DOWN CYCLE

N1 speed

(15 sec. max)

Ventilation off

STARTING CYCLE

VENTILATION CYCLESelection

Stabilisation

Time




STARTING


Start - Stop - Ventilation

Power supply of the helicopter "ON"

- Valves closed, metering needle closed by the cam.

Booster pumps switched on

- Purge of the fuel system with a return to the tank.

Starting

- The control lever is moved to the "start" position :• slight opening of the main valve

- Pushing the start push button initiates the start byelectrically supplying :

• the starter• the start injector electro-valve• the ignition system

- At 45 % of N1 (self sustaining speed) it is necessary torelease the start push button to cut the supply to the startrelay and accessories.

Note : During the start it is necessary to control theacceleration of the engine, with the control lever,and to observe the N1 speed and T4 temperature.

Stop

- After stabilisation pull the control lever to the "stop"position : the main valve closes. Note the run-downtime.

Ventilation

- Power supply switched on

- Press the ventilation button (max 15 secs) :• power supply to the starter motor via the start

contactor.




START - STOP - VENTILATION





STARTING

STARTER - GENERAL

Function

The starter motor cranks the gas generator rotating assemblyduring starting and ventilation. At the end of starting(when the rotation speed is sufficient), the starter operatesas a Direct Current generator.

Position

- On the front face of the accessory gearbox. It is securedby a clamp.


- Supplied by the aircraft manufacturer

- Type : starter-generator

- Supply : VDC through heavy duty cables (32 V max)

Main components

The starter main components are :

- The starter (starter/generator)

- The mounting flange

- The supply terminals.

Interfaces

- Starter electrical supply from the + 28 VDC supply busbar through the starter contactor

- Drive of the gas generator rotating assembly through theaccessory drive train

- Direct current supply to the aircraft system from thestarter generator when the starting phase is completed.




STARTER - GENERAL

TERMINALS

STARTER

MOUNTING FLANGE

Aircraft supply

Type :Starter-generator

Electrical supply :VDC through heavy

duty cables (32 V max)




STARTING

STARTER - DESCRIPTION

Description

The starter comprises the following components :

- Connection terminals• Excitation• Generator• Negative pole• Starter• Balance

- Casing

- Mounting flange

- Brushes

- Windings (stator and rotor)

- Cooling fan

- Drive shaft

- Commutator.




STARTER - DESCRIPTION

CASING BRUSHES

DRIVE SHAFT

COOLING FAN

BALANCEGENERATOR STARTER

NEGATIVE POLEEXCITATION

SUPPLY TERMINALS

COMMUTATORWINDINGS(stator and rotor)

MOUNTING FLANGE(on accessory gearbox)




STARTING

STARTER - OPERATION

Operation

Engine cranking

When "START" is selected the starter contactor closes andconnects the aircraft DC bus bar to the starter.

The starter then cranks the rotating assembly through theaccessory drive train.

The torque on the starter shaft is inversely proportional tothe gas generator speed and will be higher when theatmospheric temperature is low.

The N1 increases up to self-sustaining speed (45 %) atwhich point the torque becomes negative.

The supply to the starter is cut by the opening of the startercontactor.

Electrical generation

At the end of the start cycle the starter is no longerelectrically supplied and it is driven by the gas generatorthrough the accessory drive train. Thus it acts as anelectrical generator and supplies current to the aircraftcircuit.




STARTER - OPERATION

STARTTORQUE

SELF-SUSTAINING SPEED 45 %0

GAS GENERATOR SPEED

TORQUE WITH A DECREASINGAMBIENT TEMPERATURE

GENERATORSTARTER

SUPPLY TO THEELECTRICAL CIRCUIT

SUPPLY TOSTARTER RELAY

+VDC Eq

Ex

+D

+G

+




STARTING

IGNITION SYSTEM

Function

This system ensures the ignition of the fuel sprayed by thestart injectors into the combustion chamber.

Position

All the ignition system components are installed on theengine, except the electrical supply circuit.


- Type : High Energy (HE)

- Supply voltage : 10 to 32 VDC.

Main components

- Ignition units

- Ignition cables

- Igniter plugs.

Note : Refer to the following pages for the descriptionand operation of these components.




IGNITION SYSTEM

Circuit-breaker

Igniterplugs

IGNITIONUNITS

IGNITIONCABLES

IGNITERPLUGS

28 V

DC

Bu

s

Ignitionunit

Ignitionunit

Accessoryrelay

Ignitioncables

Type :High Energy

Supply voltage :10 to 32 VDC




STARTING

IGNITION UNITS - GENERAL

Function

The ignition units transform the input voltage into highenergy output.

Position

- Mounted on a support at the front right part of the engine.


- Type : High Energy

- Supply voltage: 10 to 32 VDC

- Output voltage : 2000 VAC

- Quantity : 2.

Main components

- Ignition units

- Input electrical connector

- Output electrical connectors

- Mounting flanges.




IGNITION UNITS - GENERAL

IGNITIONUNITS

MOUNTINGFLANGES

IDENTIFICATIONPLATE

Type :High Energy (HE)

Supply voltage :10 to 32 VDC

Output voltage :2000 VAC

Quantity :2




STARTING

IGNITION UNITS - DESCRIPTION -OPERATION

Description

The ignition unit comprises the following components :

- An input circuit which includes the connector and thealternating-direct converter

- A transformer

- An output circuit which includes :• A rectifier• A capacitor• A discharge tube.

Operation

The ignition unit is supplied with 28 VDC.

The converter transforms the DC voltage into an alternatingvoltage.

The transformer amplifies the alternating voltage andsupplies the rectifier.

The rectifier selects the positive phases and loads thecapacitors. The capacitor accumulates the electrical loads(positive phases) and discharges at regular intervals intothe discharge tube.

The discharge tube controls the phases of loading anddischarge.

Then the high energy voltage is delivered to the igniterplugs through the ignition cables (2000 Volts).




IGNITION UNITS - DESCRIPTION - OPERATION

+

-

CONVERTER TRANSFORMER

CAPACITOR

RECTIFIER

IGNITER PLUG

DISCHARGE TUBEDIRECTCURRENT

INPUT28 VDC

VDC

t0

VAC

t0

VAC (kV)

t0

V (kV)

t0

CAPACITORDISCHARGE

2000 V




STARTING

IGNITER PLUGS - GENERAL

Function

The igniter plugs produce sparks to ignite the fuel sprayedby the start injectors.

Position

- Mounted beside the start injectors on either side of thecombustion chamber casing.


- Type : High Energy (HE), surface discharge

- Quantity : 2.

Main components

- Plug body

- Electrode

- Mounting flange (2 bolts on the combustion chamberboss)

- Electrical connector (connection with the ignition unit)or ignition cable (according to version).




IGNITER PLUGS - GENERAL

IGNITION CABLE

IGNITION CABLE

ELECTRODE

PLUG BODY

PLUG BODY

ELECTRICALCONNECTOR

ELECTRICAL CONNECTOR

MOUNTING FLANGE

Type :High Energy

Surface discharge

Quantity :2

BEFORE MOD TU 271A

AFTER MOD TU 271A




STARTING

IGNITER PLUGS - DESCRIPTION -OPERATION

Description

An igniter plug comprises :

- An external body connected to the negative terminal

- A semi-conductor fitted in the tip of the plug

- An insulator

- A central electrode connected to the positive terminal

- An electrical connector for connection to the ignitionunit (or the ignition cable integral with igniter)

- Seals and spacers.

Operation

The high energy current produced by the ignition unit issupplied to the central electrode of the igniter plug. Itdischarges, across the semi-conductor to the plug bodycausing a powerful spark.

This spark ignites the air fuel mixture sprayed into thecombustion chamber by the start injector.




IGNITER PLUGS - DESCRIPTION - OPERATION

Spark

ELECTRICAL CONNECTOR(connection with the ignition unit)

INSULATOR

OPERATIONDESCRIPTION

SEMI -CONDUCTOR

EXTERNALBODY

(-)

CENTRALELECTRODE

(+)

INJECTORS

IGNITERPLUG

SEALS ANDSPACERS

IGNITERPLUG

COMBUSTIONCHAMBER




STARTING

IGNITION CABLES (POST MOD TU271A)

Function

The ignition cables supply the high energy current(produced by the ignition units) to the igniter plugs.

Position

- Between the ignition unit and the plugs.


- Type : multi-core nickel-plated copper wire

- Number : 2 identical independent cables

- Shielding : triple braided

- Voltage rating : 5 kVolts.

Main components

- Igniter plug cable connector

- Ignition cable (wire and shield)

- Ignition unit connector.

Description

One ignition cable includes :

- A nickel-plated copper multicore

- An outer shielding (stainless steel braid)

- Two inner shields (silver-plated copper braid)

- Two stainless steel rigid end fittings

- Two electrical connectors• One igniter plug connector (ceramic insulator, spring

and nut)• One ignition unit connector (teflon insulator, silicone

joint, spring and nut).




IGNITION CABLES (POST MOD TU271A)

ELECTRICAL CONNECTOR(to the ignition unit)

ELECTRICAL CONNECTOR(to the igniter plug)

Type :Multicore nickel-plated

copper wire

Number :2 identical

independent cables

Shielding :Triple braided

Operating voltage :5 kVolts

IGNITION CABLE(wire and shield)



For training purposes only© Copyright - TURBOMECA - 2000 ELECTRICAL SYSTEM

10-ELECTRICAL SYSTEM

- Electrical system ........................................................... 10.2

- Electrical accessories .................................................... 10.4

- Power turbine overspeed safety system ....................... 10.6

- Power turbine overspeed sensor................................... 10.10

- Tachometer box.............................................................. 10.14

- Super contingency power system ................................ 10.24

- Electrical harnesses ...................................................... 10.28 to 10.29




ELECTRICAL SYSTEM

ELECTRICAL SYSTEM

Function

The system contributes to the various indicating andcontrol functions of the engine :

- Indicating

- Fuel control

- Safety systems


- Power supply : 28 VDC from aircraft electrical system

Main components

- Engine electrical components (indicating componentsand sensors)

- Control and indicating components (aircraft)

- Electrical harnesses.




ELECTRICAL SYSTEM

Power supply :28 VDC from aircraft

ACCESSORIES AND SENSORS

ELECTRICALHARNESSES




ELECTRICAL SYSTEM

ELECTRICAL ACCESSORIES - GENERAL -

Function

The electrical accessories are involved in various enginefunctions. This chapter summarises the various accessories.

For the detail of each one refer to the appropriate chapter.

Electrical accessory classification

The accessories can be classified as follows :

- Control components (buttons, selectors, potentiometers …)

- Indicating components (indicators, lights, displays …)

- Engine accessories (controlled accessories, sensorsconnected to the aircraft).

Control components

- Switch push buttons, relay circuit-breakers, etc...

Indicating components

- Light, indicators, etc...

Engine accessories supplied by the enginemanufacturer

- Igniter plug

- Ignition Unit

- Start electro-valve

- Power turbine overspeed electro-valve (twin engineconfiguration)

- Super contingency power electro-valve (example : 1M)

- Compressor electro-valve

- Bleed valve microswitch (position)

- Oil pressure switch

- Electrical magnetic plug

- Tachometer transmitter

- Power turbine overspeed probe (twin engine)

- Pyrometric harness

- Torque transmitter

- Tachometer box

- Super-contingency power box (example : 1M).




ELECTRICAL ACCESSORIES - GENERAL

CONTROLE AND INDICATING COMPONENTS ENGINE ACCESSORIES




ELECTRICAL SYSTEM

POWER TURBINE OVERSPEED SAFETYSYSTEM - GENERAL

Function

The safety system causes the immediate shut-down of theengine in the event of power turbine overspeed.

The system (mainly designed to protect against shearingof the power shaft) requires a very quick response and ahigh reliability.

This safety system is only installed on twin-engineconfigurations.

Position

All the components are installed on the engine except thetachometer box which is mounted on the aircraft.


Overspeed setting : 120 % N2

- Automatic test :• for each start• during periodic inspection.

Main components

- Speed sensor

- Tachometer box

- Overspeed electro-valve.




POWER TURBINE OVERSPEED SAFETY SYSTEM - GENERAL


OVERSPEEDSENSOR

TACHOMETERBOX




ELECTRICAL SYSTEM

POWER TURBINE OVERSPEED SYSTEM -DESCRIPTION - OPERATION

Description

The speed sensor is mounted facing two phonic wheelswith a different number of teeth, mounted on the turbineshaft. It is connected to the tachometer box (in the aircraft).

The tachometer box electrically supplies the overspeedelectro-valve on the overspeed and drain valve.

Operation

In the event of an overspeed, when the tachometer boxreceives two frequency signals, it energises the overspeedelectro-valve to move to drain position causing the engineshut-down.




POWER TURBINE OVERSPEED SAFETY SYSTEMDESCRIPTION - OPERATION

TACHOMETERBOX


SPEEDSENSOR




ELECTRICAL SYSTEM

POWER TURBINE OVERSPEED SENSOR -GENERAL

Function

The power turbine overspeed sensor monitors N2 andtransmits the signal to the tachometer box (twin-engineversion).

Position

Screwed into the bottom of module 4 casing.


- Double pick-up

- Type : magnetic.

Main components

- Sensor

- Locating dowel

- Hollow bolt.




POWER TURBINE OVERSPEED SENSOR - GENERAL

SENSOR

LOCATINGDOWEL

Double pick-up

Type :Magnetic

HOLLOWBOLT

PHONIC WHEELS




ELECTRICAL SYSTEM

POWER TURBINE OVERSPEED SENSOR -OPERATION

Description

The sensor is fitted facing the phonic wheels, it includestwo electro-magnetic pick-ups.

The sensor is secured by a hollow bolt and is fitted with alocating pin to ensure the correct orientation.

Operation

The passage of the teeth in front of the electro-magneticsensor induces two alternating currents having a frequencyproportional to the speed and to the number of teeth :

nd x NFrequency F =

60

(nd = number of teeth, N = rotation speed in Rpm)

As the phonic wheels don't have the same number of teeth,the double sensor gives two different frenquenciesproportional to the speed.




POWER TURBINE OVERSPEED SENSORDESCRIPTION - OPERATION

nd x N60

F =

HOLLOW BOLT

SENSOR

PHONIC WHEELS

TO THE TACHOMETER BOX

SENSORPHONIC WHEEL

ELECTRO-MAGNETICPICK-UP

PHONICWHEEL

TACHOMETERBOX




ELECTRICAL SYSTEM

TACHOMETER BOX - GENERAL

Function

To supply the overspeed electro-valve in case of anoverspeed detection and to control the operation of thebleed valve (according to version).

Position

- In the aircraft


- Electronic box

- Automatic test

- Periodic test.

Main components

- Push-buttons• test• rearming

or selector according to version

- Electrical connector(s).




TACHOMETER BOX - GENERAL

TEST

TESTPUSH-BUTTON

REARMINGPUSH-BUTTON

TESTSELECTOR

ELECTRICALCONNECTOR

OVERSPEEDCONNECTOR

ELECTRICAL CONNECTORFOR THE COMPRESSORBLEED VALVE CONTROL




ELECTRICAL SYSTEM

TACHOMETER BOX - DESCRIPTION

Description

The tachometer box is mounted in the aircraft, it is connectedto the overspeed sensor by an electrical harness.

It includes two frequency detectors, a V relay, a bi-stablerelay S and S', a rearming and a test push button.

A cross monitoring system between the two overspeedboxes inhibits the overspeed system of the other engine incase of overspeed.




TACHOMETER BOX - DESCRIPTION

TEST

OSCILLATOR

N2

N2

120 %

120 %

VS

ENGINE

SHUT-DOWN

S'

OVERSPEED ELECTRO-VALVE

INHIBITION OF THE STARTING

INHIBITION OF THE ENGINE 2 SYSTEM

25 %

25 %

REARMING

EVENTUAL INHIBITION OF THIS SYSTEM




ELECTRICAL SYSTEM

TACHOMETER BOX - OPERATION (1)

Power on

At power on, the sensors give the F1 and F2 frequenciesto frequency detectors which supply the light through themutual monitoring system (up 25 % of N2).

An eventual rearming is possible.

Overspeed condition

In the event of N2 overspeed (N2 ≈ 120 %) the two signalsof N2 (F1 and F2) are supplied to the two frequencydetectors which complete the circuit through relay V.

Relay V closes its contacts :• supplying relay S• breaking the circuit of the other engine.

The contacts of relay S• open the other engine's overspeed circuit• supply the overspeed solenoid• open the start circuit• open the overspeed light circuit.





POWER ON

POWER ONOVERSPEED

- The light turns on (up to 25 % of N2)

- Rearming (eventually)

OVERSPEED

- Supply of the mono-stable relay V

- Supply of the bi-stable relay S

- Supply of the overspeed electro-valve

- Inhibition of engine 2 system

- Inhibition of the start

TEST

OSCILLATOR

N2

N2

120 %

120 %

VS

ENGINE

SHUT-DOWN

S'




25 %

25 %

REARMING

EVENTUAL INHIBITION OF THIS SYSTEM




ELECTRICAL SYSTEM


Automatic monitoring (A, B, C, D, K, M versions)

The condition of the pick-up signals is checked at eachstart with the light turning-off above 25 % N2.

Periodic test

Engine stopped, operation of the push button simulates anoverspeed :

• the light goes off• the electro-valve is supplied• the start system is inhibited

After this test it is necessary to rearm the system.

Rearming

When the rearm push button is pressed the relay S' issupplied and the relay returns to the normal position.





AUTOMATIC MONITORING

AUTOMATIC MONITORINGA, B, C ,D, K, M VERSION :

whatever N1

N2 (x) N2 (y)

OK OK

OK

OK

0

0

0

0

Light off

Light on

Light on

Light on

TEST

OSCILLATOR

N2

N2

120 %

120 %

VS

ENGINE

SHUT-DOWN

S'




25 %

25 %

REARMING

EVENTUAL INHIBITION OF THIS SYSTEMOVERSPEED MANUAL TEST

OVERSPEEDMANUAL TEST

- Supply of the oscillator 120 % *

- Oscillator inhibited for N2 > 25 %




ELECTRICAL SYSTEM


Automatic monitoring (1E, 1S versions)

This protection doesn't exist on all boxes.

- Above 25 % N2 and below 83 % N1 : the loss of one N2speed signal is indicated by the light staying "on".

- Above 25 % N2 and 83 % N1 :• the loss of one N2 speed signal is also indicated by

the light staying "on"• the loss of two N2 speed signals causes the engine to

be shut down by the overspeed system.

- Above 25 % N2.• the loss of the N1 speed signal or any defect of the

protection stage is indicated by the flashing of thelight.

Note : In all cases of engine shut down by overspeed,starting is not possible.





TEST

OSCILLATOR

N2

N1

N2

120 %

120 %

VS

ENGINE

SHUT-DOWN

S'




25 %

1S, 1E

VERSION

83 %

25 %

REARMING

EVENTUAL INHIBITION OF THIS SYSTEM1E, 1S VERSION MONITORING

AUTOMATIC MONITORING1S, 1E VERSION :

N1 < 83 %

N2 (x) N2 (y)

OK OK

OK

OK

0

0

0

0

Light off

Light on

Light on

Light on

N1

OK

0

Light off

Light flashing

N1 > 83 %

N2 > 25 %

N2 (x) N2 (y)

OK OK

OK

OK

0

0

0

0

Light off

Light on

Light on

Engine shut-down




ELECTRICAL SYSTEM

SUPER CONTINGENCY POWER SYSTEM -GENERAL

Function

The purpose of this system is to provide on extreme powerrating : super contingency power rating. This system isonly available on some versions.

The control box, delivered with the engine ensures:

- the recording and display of the engine operating hoursin hundreths of an hour.

- the recording and indication by a red flag of the use ofS.C.P.

- the ouput of a duplicate signal to a flashing light in thecockpit to indicate use of S.C.P.

Position

The electro-valve is on the FCU, the control box in thehelicopter.


- Selection by button on the collective pitch lever.

Main components

- Control box

- Super contingency power electro-valve.

Note : The S.C.P. control box is associated with themodule M03.




SUPER CONTINGENCY POWER SYSTEM - GENERAL

S.C.P. ELECTRO-VALVE

ELECTRICALCONNECTORS

ENGINEHOUR COUNTER

RED FLAG

S.C.P.CONTROL BOX

(associated with module M03)




ELECTRICAL SYSTEM

SUPER CONTINGENCY POWER SYSTEM -DESCRIPTION - OPERATION

Description

The electro-valve on the fuel control unit opens whenelectrically supplied to permit an increase of modulatedpressure and therefore an increase of the max availablerating.

The control box belongs to module n° 03, it indicates theengine hours and the operation of S.C.P.

The system includes :• a selector on the collective pitch-lever• an automatic armament switch in the torque indicating

system.• a flasher relay• an indicating device (light and flag)

Operation

S.C.P. Arming

Two conditions are necessary for the arming of the S.C.P.system:

- the pilot must select S.C.P.- there must be a torque difference between the engines

≥ 22 %.

The detection logic in the torque indicating system closesits contact thus supplying, through the pilot's selector, theS.C.P. electro-valves of both engines and the S.C.P. lightin the cockpit. Super Contingency Power will now beavailable on the operative engine.

Rating detection

From 50 to 102.5 % N1 the S.C.P. box counts the enginehours.

From 102.5 to 103.8 % N1, that is in S.C.P. mode, theengine hours counting is increased by a multiplicationfactor of 4.4. The S.C.P. light is on.

If the N1 remains above 103.8 % for more than 5 secondsthe bi-stable relay is supplied and relay (C) is suppliedcausing the flashing of the S.C.P. light. Simultaneously thered flag is activated and appears in the window.

Note 1 : Normal max N1 is 102.4 % for the Arriel 1M1/ 1MN1 without S.C.P. In S.C.P. mode the maxN1 is 105 %.

Note 2 : The maximum authorised accumulatedoperating time in S.C.P. is 1 minute. The use ofthis rating requires replacement of the engineand the S.C.P. box.




SUPER CONTINGENCY POWER SYSTEMDESCRIPTION - OPERATION

C

COLLECTIF PITCHS.C.P. SELECTOR

TORQUEINDICATOR

FLASHERUNIT

RELAY

RELAY TOELECTRO-VALVES

+ 28 V

+ 28 V

+ 28 V

FLAG S.C.P.ELECTRO-VALVE

WINDOW

SIGNAL FROMN1 TACHO. GEN.

TON1 INDICATOR

S.C.P.CONTROL BOX

S.C.P.

BI-STABLE RELAY

ENG. HOURS

COUNTER

TO OTHERENGINE

(SCP electro-valve)

(T x4.4)

T:5 secsN1 ≥ 103.8 %

N1 ≥ 102.5 %

N1 ≥ 50 %

D ≥ 22%

(T x1)




ELECTRICAL SYSTEM

ELECTRICAL HARNESSES

Function

Harnesses link the engine accessories to the aircraft.

Description and operation

All engine versions have a multi-pin plug for the engine/aircraft interface and a second electrical plug for thepyrometric system (except on ARRIEL 1S1 : only oneelectrical plug for the two harnesses).

On the twin-engine version : a harness for the speeddetection to stop the engine in case of overspeed.

Note : The starter-generator cables must also bementioned.




ELECTRICAL HARNESSES

SPEED DETECTIONHARNESS FOR THE

OVERSPEED SYSTEM(twin-engine version)

PYROMETRICHARNESS

ACCESSORYHARNESS

ARRIEL 1S1 : only one connector



For training purposes only© Copyright - TURBOMECA - 2000 ENGINE INSTALLATION

11-ENGINE INSTALLATION

- Engine compartment ..................................................... 11.2

- Engine mounting............................................................ 11.4

- Power drive .................................................................... 11.8

- Air intake........................................................................ 11.10

- Exhaust system .............................................................. 11.12

- Engine system interfaces .............................................. 11.14

•Oil system .................................................................................... 11.14

•Aircraft LP fuel system .............................................................. 11.16

•Manual controls .......................................................................... 11.18

•Air system.................................................................................... 11.20

- Drain system .................................................................. 11.22

- Fire protection ............................................................... 11.24 to 11.25




ENGINE INSTALLATION

ENGINE COMPARTMENT

Function

The engine compartment accommodates the engines andensures their ventilation.

Position

- At the rear of the helicopter main gearbox.


- Insulated compartments

- Compartment ventilation by air circulation.

Main components

- Firewalls

- Cowlings

- Support platform.

Description

A typical twin-engine installation includes the followingcomponents :

- Two areas separated by a central firewall :• Right engine area• Left engine area

- Three main firewalls :• Front firewall• Rear firewall• Central firewall.

- The main engine mountings

- Two main cowlings :• The air inlet cowling which permits access to the air

intake• The engine cowling which permits access to the

engine and to the exhaust system.

The compartment ventilation is ensured by air circulationin order to maintain an acceptable temperature in thevarious areas.

The ventilation can be increased by the compressor bleedvalve air discharging into the engine compartment.




ENGINE COMPARTMENT

FRONTFIREWALL

MAINGEARBOX

ENGINE CENTRALFIREWALL

REARFIREWALL

ENGINECOWLING

AIR INLETCOWLING

SUPPORTPLATFORM

ENGINEMOUNTING

EXAMPLE OF SINGLE ENGINEINSTALLATION

EXAMPLE OF TWIN-ENGINEINSTALLATION




ENGINE INSTALLATION

ENGINE MOUNTING - GENERAL

Function

The engine mountings attach the engine to the airframe.

The lifting brackets permit the removal and installation ofthe engine.

Position

- Front mounting : at the front lower part of the accessorygearbox casing

- Rear mounting : at the front lower part of the reductiongearbox casing, or on the protection tube (according toversion)

- Lifting brackets : 2 at the front part and one at the rear.

Main components

- Front mounting : flange or yoke (according to version)

- Rear mounting : clamps and cradle (according to version)

- Engine lifting points :• two brackets on the centrifugal (compressor casing

flange)• one bracket on the power turbine casing flange.




ENGINE MOUNTING - GENERAL

FRONT LIFTINGBRACKETS

REAR LIFTINGBRACKET

FRONTFLANGE

CRADLE CLAMPS




ENGINE INSTALLATION

ENGINE MOUNTING - FUNCTIONALDESCRIPTION

There are two types of engine mounting depending on theengine variant.

- Variants A, B, C, D and M :

Front support - ring of bolts on the front flange.

Rear support - a cradle under the protection tube, securedby two clamps.

- Variants E, K and S :

Front support - yoke bolted to the front face of theaccessory gearbox, supported on two trunnion mounts.

Rear support - a rod connects to the bracket on thebottom of module 5.




ENGINE MOUNTING - FUNCTIONAL DESCRIPTION

MOUNTING BYCLAMPS ON THE

PROTECTION TUBE

TYPE A - B - C - D - M

REARMOUNTING

TYPE E - K - S

MOUNTING BY THEFRONT SUPPORTCASING FLANGE

TYPE A - B - C - D - M

MOUNTING BY TWOATTACHMENT

POINTS ON THEAIRFRAME

TYPE E - K - S




ENGINE INSTALLATION

POWER DRIVE

Function

The power drive transmits the engine power to the helicoptertransmission system.

The link is made by a transmission shaft designed toabsorb the engine torque and slight misalignements (supplyby aircraft manufacturer or TURBOMECA according toversion)

Position

- Between the engine and the helicopter main gearbox.


- Shaft designed to absorb the engine torque and slightmisalignments

- Rotation speed : 6000 RPM at 100 %.

Main components

The main components are :• The engine drive shaft flange• The flector (engine end)• The adapting flange• The drive shaft• The flexible coupling (MGB end)• The main gearbox input flange.


The engine drive shaft consists of a steel tube, fitted withthe following elements at each end :

- A triangular flange connected to the MGB input flangewith a flexible coupling

- A splined flange, connected to an adaptor flange whichis connected to the engine drive shaft flange with aflector.

The flexible couplings are installed between the flanges.They transmit torque, absorb shock and vibration andallow slight misalignment.

Note : In single engine versions, the free wheel unit drivesthe main gearbox and the tail rotor shaft drive.




POWER DRIVE

MAIN GEARBOXINPUT FLANGE

DRIVESHAFT

ENGINEDRIVE-FLANGE

FLEXIBLECOUPLING

SPLINES

ADAPTOR FLANGE(splined)

FLECTOR

1S VERSION

1E VERSION




ENGINE INSTALLATION

AIR INTAKE

Function

The air intake system directs the ambient air into theengine.

Position

- In front of the engine.


- Type : Static or dynamic, annular

- Air flow : 2.5 kg/s (5.5 lb/sec.).

Main components

- Helicopter air intake

- Intake duct

- Anti-icing system.


A circular flange on the compressor casing permitsconnection of the aircraft air intake duct. The admission ofair can be made through a static or a dynamic intake whichcan be provided with protection devices (filters, anti-icing...). A pressurized seal can also be fitted to improvethe connection sealing. Some versions are provided with adevice for compressor washing.




AIR INTAKE

SEALANTI-ICINGAIR DUCT

FILTER

UNION FORCOMPRESSOR WASHING




ENGINE INSTALLATION

EXHAUST SYSTEM

Function

The exhaust system discharges the exhaust gas overboard.

Position

- At the rear of the engine.


- Type : divergent

- Gas temperature : 600 °C (1080 °F).

Main components

- Engine exhaust pipe

- Exhaust extension.


The exhaust expels the gases directly but it can be adaptedto the aircraft by means of an extension. The enginecompartment ventilation can be accelerated by venturieffect between the engine exhaust pipe and the aircraftduct.




EXHAUST SYSTEM

VENTURI TO ACCELERATE THECOMPARTMENT VENTILATION

EXHAUST PIPE EXTENSION




ENGINE INSTALLATION

ENGINE SYSTEM INTERFACES (1)

Oil system interfaces

For each engine, the oil system has three interfaces asfollows :

- Oil return line to the aircraft oil cooler

- Oil supply line to the oil pump pack

- The vent line : from the oil tank to the accessory gearboxand to the exhaust.




OIL SYSTEM INTERFACES


AIRCRAFT ENGINE

OIL SUPPLY

OIL RETURNTO THE COOLER

BREATHING




ENGINE INSTALLATION


Aircraft LP fuel system

Function

The system supplies the engine with fuel under determinedconditions of pressure, flow, temperature and filtering.


- Filtering 10 micron.

Main components

- Fuel tank

- Booster pump

- Filter assembly

- Fuel shut-off valve

- Fuel inlet union

- Return to tank union.


The interface comprises the union on the FCU and returnto tank union. The aircraft system may include variousdevices : vent, level indication, filler neck, booster pump,pressure indicator, flowmeter. The booster pump willprime the engine system and prevent cavitation of thepump.

The filtering unit, normally fitted with a pre-blockageindicator and a by-pass valve is in the line before the shut-off valve which is used to isolate the engine compartmentfrom the aircraft system.

Note : In the 1S, 1E versions, the fuel inlet union islocated on the LP fuel system, located under theengine.




AIRCRAFT LP FUEL SYSTEMENGINE SYSTEM INTERFACES (2)

FUEL SHUT-OFFVALVE

FILTER UNIT(filtering 10 microns)

FUELTANK

BOOSTERPUMP

(except 1S)

FUEL INLETUNION

RETURN TOTANK UNION

1S, 1E VERSIONS






ENGINE INSTALLATION


Manual controls

Function

To allow the control of the fuel valves and of the anticipator.

Position

The engine control lever and the collective pitch lever arein the cockpit and are mechanically connected to theF.C.U.

Main components

- Control lever

- Collective pitch lever

- Fuel control unit.


- Engine control lever (Lever actuating 2 valves and acam in the fuel control unit : see chapter "fuel system"and aircraft manuals for the mechanical linkage).

- Anticipator control (Linkage with the helicoptercollective pitch : see operation of the anticipator in thechapter "engine control" and details of the mechanicalconnection in the aircraft manuals).




MANUAL CONTROLS


CONTROL LEVER

FUEL VALVECONTROL

ANTICIPATORCONTROL

COLLECTIVEPITCH LEVER




ENGINE INSTALLATION


Air system

Function

The system provides warm compressed air to the aircraftfor the aircraft services.

Position

One tapping boss on each side of the centrifugal compressorcasing.

Main components

Air tapping points (x 2).


Aircraft pipes can be connected to the two tapping pointsto supply a given flow of P2 air. The flow is limited byrestrictors but any air bleed affects engine performance.

Possible uses of the air

- Cabin heating

- Pressurized seal

- Air intake anti-icing

- Particle separator...

Note : Refer to aircraft manuals for detailed descriptionof these systems.




AIR SYSTEM


P2

P2 TAPPING




ENGINE INSTALLATION

DRAIN SYSTEM

Function

To drain fluids from certain engine components.

Position

- Various pipelines on the engine connected to the aircraftdrain system.


- Stainless steel tubes.

Main components

- Combustion chamber drain valve- General vent- F.C.U. drive drain- Overspeed and drain valve- Exhaust pipe drain- Output shaft casing drain- Air vent of the Gas generator rear bearing- Rear bearing collector drain.

Description

A drain collector is fitted on a bracket at the bottom of theaccessory gearbox casing and is connected by a flexiblepipe to an aircraft drain.

Four drain tubes are connected to the drain collector, theoutput casing drain, the pump drive drain, the combustionchamber drain and the overspeed and drain valve.

The gas generator rear bearing vent pipe vents into theengine compartment.

The engine breather comprises a T union on the upper rightside of the accessory gearbox. Connected to the front ofthis union is the oil tank breather and to the rear, the pipewhich discharges into the exhaust.

The rear bearing supply collector has a drain into theengine compartment.

The exhaust pipe drain connects into a pipe which isconnected to an aircraft overboard drain.




DRAIN SYSTEM

AIR VENT OF THEGAS GENERATOR

REAR BEARING

COMBUSTION CHAMBERDRAIN VALVE

FCU DRIVEDRAIN


OUTPUT SHAFTCASING DRAIN

TO AIRCRAFTREAR BEARING

COLLECTOR DRAIN

EXHAUST PIPEDRAIN

GENERALVENT




ENGINE INSTALLATION

FIRE PROTECTION

Function

The fire protection system comprises overtemperaturedetection in the various engine areas, the indication in thecockpit, the extinguishing function.


- Engine manufacturer supply (except 1S)• Bi-metallic detectors.

- Aircraft manufacturer supply• Optical detectors (1S only)• Indicating system• Extinguishing system.

Main components

- Engine• Six detectors (except : 1E : one detector, 1S : no

detector)• Harness (fire proof cables).

- Aircraft• Two detectors (1S only)

• Extinguishing system

• Test system.


The detection is ensured by non sealed detectors withnormally closed contact (1A, B, C, D, K, M) or one sealeddetector with normally open contact (1E) or by means ofan aircraft mounted optical device (1S).

Some detectors have a built-in resistor which permits thediscrimination of circuit conditions (1C, D, K, M) : normal,overtemp, harness failed.

In the case of detectors with normally closed contact, thedetectors are installed in series and have a setting whichcorresponds to the engine area of location ("cold" area or"hot" area) and thus they are not interchangeable.

Note : "cold" area or area 1 : area located forward of thejunction of the compressor and the combustionchamber mounting flanges.

"hot" area or area 2 : area located rear of the samejunction.




FIRE PROTECTION

1A,B,C,D,K,M (6 detectors)

1E(1 detector)

1S (2 detectors on aircraft)

POSITION OF DETECTORS

NON SEALED DETECTOR(1A, B, C, D, K, M )

SEALED DETECTORAT REST (1E )

Detection

logic

+

+

+

Extinguishingbutton

Test button

Alarm

EXTINGUISHING SYSTEM(bottle, manifold... )

Area 1 (cold) Area 2 (hot)

Aircraft Engine

EXAMPLE OF FIRE DETECTION / EXTINGUISHING SYSTEM



For training purposes only© Copyright - TURBOMECA - 2000 OPERATING LIMITATIONS AND PROCEDURES

12-OPERATING LIMITATIONSAND PROCEDURES

- Operating limitations ................................................... 12.2

- Operating procedures .................................................. 12.6 to 12.9




OPERATING LIMITATIONS AND PROCEDURES

OPERATING LIMITATIONS (1)

The engine operating limitations are defined in the officialmanuals, however the following figures provideinformation for training purposes.

Operating envelope

The engine is designed to operate within a clearly definedclimatic range of temperature and pressure altitude e.g. : -50°C to +50 °C (-58 °F to 122 °F) and -500 m to +6000 m (-1640ft to 19680 ft).

The starting envelope also has given limits e.g. : -500 m to4500 m (-1640 ft to 14760 ft) and -50 °C to +50 °C (-58 °F to122 °F) depending on the fuel and oil used.

Gas generator rotation speedThe main limitations are :

- AEO max T/O 5 minmax continuous : 98 % N1

- OEI max contingency - (2 min 30 sec)inter contingency - unlimitedsuper contingency - according to version.

Power turbine rotation speed

The main limitation is :

- Overspeed : 120 % N2 (twin-engine).

t4 gas temperature

These figures vary according to version :

- Max during start : 750 °C

- Max (t < 10 sec.) : 865 °C

- Max OEI (2 min 30 sec) : 941 °C

- Max take-off : 912 °C (< 5 min).





t0

Zp

GAS GENERATORROTATION SPEED

- AEO max take-off (< 5 min)- AEO max continuous (98 % N1)- OEI (< 2 min 30 sec)- OEI inter contingency (unlimited)- OEI super contingency (according to version)

POWER TURBINEROTATION SPEED

Twin-engine :- Power turbine overspeed 120 % N2

FLIGHT ENVELOPE

- Flight- Starting

GAS TEMPERATURE

- Max during start- Max (t < 10 sec.)- Max OEI (2 min 30)- Max take-off






Torque

The torque limit is imposed by the aircraft transmission.The max torque limits are given for steady power settingsand for transitory overtorque in AEO and OEI modes.

Oil

There are various limits associated with the oil system,e.g. consumption = 0.3 l/h ; max pressure 800 kPa(116 PSI) ; min pressure 130 kPa or 90 kPa according toversion (18.85 PSI), max temperature 115 °C (239 °F).

Starting - shut-down

There are many limits associated with engine starting :

- Min voltage before start (e.g. 25 V)- Min voltage during start (e.g. 15 V)- Start duration : between 25 and 30 sec- Ventilation duration : < 15 sec- Number of consecutive starts - according to version- Waiting time after 3 start attempts (e.g. 20 min)- Stabilisation time before shutdown : 60 sec- Run-down time : > 30 sec from 30 % to 0 % N1.

Other limitations

Max air tapping rate , electrical consumption, load factors,vibration, etc.





TORQUE

- Stabilised max torque- Transient max torque

MISCELLANEOUS

- Air bleed- Electrical consumption- Loads factors- Vibration

OIL

- Max consumption - Max pressure- Min pressure- Max temperature

STARTING - SHUT-DOWN

- Electrical voltage - Number of consecutive starts- Stabilisation, run-down and ventilation times





OPERATING PROCEDURES (1)

The operating procedures are considered for trainingpurposes only. Refer to the aircraft manual.

Pre-start checks

- Inspections, checks…

Starting

- Power "on"

- Control lever to "start position"

- Start button pressed and held. The engine starts andaccelerates. During start, check : N1, N2, t4, oil Pr andt°. At 45 % N1, release the "start button"

- Control lever moved to "Flight". The engine acceleratesup to nominal rotor speed.

Shut-down

- Stabilisation

- Control lever to "stop". The engine shuts down : checkthe rundown time.

Ventilation

- Control lever to "stop"

- Cranking button "on" (and maintained). The engineaccelerates without ignition and fuel : ventilation shouldnot exceed 15 seconds.

Relight in flight

- Procedure identical to start on ground.

Note : Confirm shut-down before start attempt. Wait untilN1 has decelerated.




START - SHUT-DOWN - VENTILATION - RELIGHT


SHUT-DOWNSTARTING

RELIGHT IN FLIGHT VENTILATION

90°

52°

45°5°






Flight

- Control lever in "flight" position. Automatic control :monitor engine parameters, especially the N1 indication.

Engine failure (twin-engine)

The engine remaining in operation supplies the powerrequired, within its limitations (MCP : 2 min 30 sec).

Control system total failure

The manual control procedure can be applied ("plus" and"minus" range) : close monitoring of parameters.

Training to engine failure

This procedure must be carried out with a reduced helicoptermass, (refer to flight manual).





ENGINE FAILURE(twin-engine)

FLIGHT

TRAINING TOENGINE FAILURE

CONTROL SYSTEMTOTAL FAILURE

90°

52°

45°5°



For training purposes only© Copyright - TURBOMECA - 2000 VARIOUS ASPECTS OF MAINTENANCE

13-VARIOUS ASPECTS OFMAINTENANCE

- Maintenance concept .................................................... 13.2

- TBOs and life limits....................................................... 13.4

- Preventive maintenance ................................................ 13.6

- "On-condition" monitoring .......................................... 13.8

- Corrective maintenance ................................................ 13.10

- Lubricants - Fuels - Materials ..................................... 13.12

- Tooling ............................................................................ 13.14

- Technical publications .................................................. 13.16

- Product support ............................................................ 13.22 to 13.23




VARIOUS ASPECTS OF MAINTENANCE

MAINTENANCE CONCEPT

Introduction

The engine is designed to have a high availability rate withreduced maintenance.

The main aspects of the maintenance concept are thefollowing :

- Effective modularity

- Good accessibility

- Reduced removal and installation times

- On-condition facility

- Quick repair.

Maintenance levels

Four maintenance levels can be considered :

First line maintenance (level "O") : engine installed inthe aircraft.

- Scheduled and preventive maintenance• Checks and inspections• Life limit or time-ex removal.

- Corrective maintenance• Fault detection• Component replacement (LRU)• Check.

Second line maintenance (level "I") : engine maintenancein a workshop.

- Corrective maintenance : SRU and module removal andinstallation.

Third line maintenance (level "H") : deep maintenancewhich involves module repairs.

- Corrective maintenance : component replacement.

Fourth line maintenance (level "D") : overhaul andrepair in specific workshop.

- Maintenance scheduled when the TBO is completed orwhen the life limits of some components are reached

- Corrective maintenance.

Other aspects of maintenance


Note : LRU - Line Replaceable Unit

SRU - Shop Replaceable Unit.




MAINTENANCE CONCEPT

2nd LINE MAINTENANCE(level "I")

(engine removed)- Corrective maintenance

(modules, SRU)

MAINTENANCE LEVELS

3rd LINE MAINTENANCE(level "H")

(engine removed)- Deep maintenance

1st LINE MAINTENANCE (level "O")(engine installed on aircraft)

- Scheduled or preventivemaintenance

- Corrective maintenance

4th LINE MAINTENANCE(level "D")

(engine removedin specific workshop)

- Scheduled maintenance(overhaul, repair)

- Corrective maintenance





TBOs AND LIFE LIMITS

Engine, module and accessory TBOs

TBOs (operating Time Between Overhauls) are definedfor the engine, the modules and the accessories. TheseTBOs, determined by tests and experience, are subject toan extension programme.

Component life limits

Certain components (mainly rotating parts such ascompressor, turbines, injection wheel, flectors…) have alife limit which requires the part to be scrapped when thelimit is reached.

The life is measured in operating cycles.

Counting of hours and cycles

A cycle is a clearly defined operating sequence. Cyclecounting is effected either manually or automatically. Themethod of counting cycles and the various limits aredescribed in Chapter 5 of the maintenance manual.

A counting check (comparison between automatic countingand manual counting) is a procedure planned in the periodicmaintenance.

A simple check can be carried out by comparing the twoengine readings for a given period of operation.

TBO components

- Engine

- Modules

- Certain accessories.

Life limited components

- Axial and centrifugal compressors

- Injection wheel

- Turbines.




TBOs AND LIFE LIMITS

TBO

- Engine- Modules- Accessories

AUTOMATIC COUNTING

COUNTING

- Manual counting- Automatic counting- Counting check

LIFE LIMITS

Cycles for :- Compressors- Turbines- Injection wheel

CYCLECOUNTER





PREVENTIVE MAINTENANCE

Preventive maintenance includes the procedures whichmust be systematically carried out.

Servicing inspections

- Inspection before the first flight of the day

- Inspection after the last flight of the day.

(Refer to maintenance manual).

Periodic inspections

- These procedures can be "blocked" (at fixed intervalsfor all the procedures) or staggered (each procedure isdistributed over a period of time to reduce the turnaroundtime while still respecting the intervals)

- 100 hour, 500 hour, 1500 hour or calendar inspections(18 months)

- Special inspections :• Particular inspections• Inspections according to airworthiness.

Main inspection points of preventive maintenance

- Visual inspections

- Magnetic plug and filter inspection

- Oil sampling for analysis

- Level checks

- Compressor cleaning (according to operating conditions)

- Operating checks and ground run test

- Cycle counting check

- Static droop check

- Run down check.




PREVENTIVE MAINTENANCE

SERVICING INSPECTIONS

- Inspection "after the last flight of the day"- Inspection "before the first flight of the day"

PERIODIC INSPECTIONS

- Procedure "blocked" or "staggered"- 100 hour inspection- 500 hour, 1500 hour or calendar inspections (18 months)- Special inspections

MAIN INSPECTION POINTS

- Visual checks : air intake, compressor, exhaust, turbine, casings, attachments, pipes, wiring, controls- Inspection of filters : oil filter, fuel filter, air tapping unions and jets- Inspection of magnetic plugs- Oil sampling (for analysis)- Oil level (and replenishment if required)- Compressor cleaning (depending on operating conditions)- Ground run test- Static droop test- Run down check- Cycle counting check





ON-CONDITION MONITORING

When applying on-condition maintenance, the maintenanceprocedures are carried out according to the condition ofengine components. It requires a monitoring which includesappropriate procedures studied during the engine design.

Objectives of on-condition monitoring

The objective is to increase safety and to reducemaintenance costs.

This is achieved because the monitoring ensures an earlydiagnosis of defects which could have seriousconsequences ; on the other hand, monitoring avoidsunnecessary maintenance tasks.

On-condition monitoring resources

On-condition monitoring implies an appropriate design ofthe engine which allows the use of monitoring tools.

The following procedures are considered :

- Borescopic inspection : this permits inspection of internalparts which are not accessible without disassembly :compressor, combustion chamber and turbine. A specialtool is used to allow direct visual inspection of the parts

- Lubricating oil check : various methods are used to checkfor the contamination of the oil (magnetic plugs, strainers,sampling). Samples of oil are taken at regular intervalsand the samples are analysed to measure thecontamination and anticipate incipient failures (analysisby magnetoscopy, ferrography, spectrometric oilanalysis)

- Vibration level check : the vibration level of the rotatingassemblies gives an indication of the engine condition.Sensors installed at given points are used to measure thevibration level. This type of check is carried out duringperiodic inspections or according to engine condition

- Visual inspection : conventional visual inspections arealso considered for on-condition monitoring (air intakeinspection , exhaust pipe inspection , exhaust and engineexternal inspections…).




ON-CONDITION MONITORING

OBJECTIVES OFON-CONDITION MONITORING

BORESCOPIC INSPECTION

MAGNETIC PLUGS

VIBRATION CHECK STRAINERS

OIL SAMPLINGVISUAL INSPECTION

- To increase safety- To reduce maintenance costs





CORRECTIVE MAINTENANCE

The objective of corrective maintenance is to put theengine back into normal service as soon as possible.Corrective maintenance includes all procedures whichmust be carried out when required (failure, defect…). Itimplies general and particular activities.

Corrective maintenance main tasks

- Removal and installation : removal and installation of thecomplete power plant, of the accessories and of themodules and of some engine components as required.

Note : Assembly and disassembly of the engine is dealtwith in general overhaul and repair

- Functional checks : functional check of systems, andaccessories…

- Condition checks

- Adjustments

- Miscellaneous procedures : cleaning, storage…

- Repairing (components may be repairable or consumable)

- Fault finding (refer to chapter 15 "FAULT ANALYSISAND TROUBLE SHOOTING")

- Particular instructions : for example, procedures in theevent of oil contamination, surge, heavy landing, handlingaccident, lightning strike.




CORRECTIVE MAINTENANCE

CORRECTIVE MAINTENANCEMAIN TASKS

- Removal and installation

- Functional and condition checks

- Adjustments

- Miscellaneous procedures (cleaning, storage ...)

- Repairing (consumable or repairable components)

- Fault finding

- Particular instructions

OBJECTIVES OF CORRECTIVEMAINTENANCE

- To put the engine back into normal

service as soon as possible





LUBRICANTS - FUELS - MATERIALS

This part deals with information on materials used : fuels,lubricants, greases, fluids.

Lubricants

The engine manufacturer recommends the use of syntheticoils which keep their lubricating properties over a widetemperature range and have a longer operating life.

Medium viscosity oils (5 cSt) are more particularlyrecommended but other types (3 to 3.9 cSt) may be used asan alternative.

The maintenance manual (chapter 71.00.02) containsspecification tables and precautions.

We shall remind you here that the mixture of oils ofdifferent types is not recommended. Therefore the systemshould be flushed when the oil specification is changed.

Fuels

The quality of the fuel is essential for the correct operationof the engine. It is particularly important to ensure a properfuel supply : specification, water content, purity…

The maintenance manual (chapter 71.00.02) contains tablesindicating the fuel types with the corresponding US, UK,NATO and French specifications.

Two types of fuel can be considered :

- The "normal fuels" which can be used without restrictionin all the operating envelope

- The "emergency fuels" (or replacement fuels) whichmay be used, but with particular restrictions and for alimited time in order not to affect the engine TBO.

Materials

Various products are used for engine parts maintenance.

For example graphite grease, molybdenum disulphide forthe installation of parts, cleaning and inhibiting products.

The various products must be used carefully, for instanceuse of trichlorethylene on titanium alloy parts is forbidden.




LUBRICANTS - FUELS - MATERIALS

FUELS(maintenance manual, chapter 71.00.02)

- Normal fuels : (without restriction)

- "Emergency" fuels (with particular restrictions : operating times, additives…)

LUBRICANTS(maintenance manual, chapter 71.00.02)

- Normal lubricants : medium viscosity synthetic oils

- "Emergency" lubricants : medium and low viscosity oils

- No mixture of oils of different specifications

- Flushing of the system when the oil specification is changed

MATERIALS

- Part installation : graphite grease, molybdenum disulphide…

- Cleaning : water, fuel, alcohol, detergent…

- Storage : waterproof product





TOOLING

This part deals with information on maintenance tools.

Tools

Maintenance requires certain tools, but in addition to thenormal standard tools, a certain number of special toolsand test equipment can be used.

During a training course, these tools are used to carry outpractical work : current maintenance and modularmaintenance tools.

The tools are described in an illustrated catalogue and alsoin the maintenance manual.

In the catalogue, tools can be identified either by thefunction, or by the aspect or the reference.

Tool classification

We can distinguish :

- Tools used for standard practices (e.g. : thread insertreplacement)

- Blanking devices

- Handling equipment (e.g. : lifting device, engine support,transport trolley)

- Packing equipment (e.g. : wooden or metal container)

- Tools used for removal and installation (e.g. : extractors,wrenches, supports for module removal and installation)

- Tools for miscellaneous procedures and checkingequipment :

• Oil drain• Compressor washing• Vibration check• Borescopic inspection• Pressure transmitter inspection (torquemeter, fuel,

oil)• Ignition system inspection• Harness inspection• Electrical measurement• Fuel injection system permeability.

Note : The tools are to ISO standard.




TOOLING

- Normal- Specific

TOOLS

Identification by :- Function- Picture- Reference

TOOL CLASSIFICATION

CATALOGUE

- Standard practices- Blanking devices- Handling equipment- Packing equipment- Removal and installation- Checking procedures:

• Oil drain• Compressor washing• Vibration check• Borescopic inspection• Pressure transmitter inspection• Ignition system inspection• Harness inspection• Electrical measurement• Fuel injection system

permeability





TECHNICAL PUBLICATIONS - GENERAL

This part deals with the engine technical documentation.

Operation documents

The operation documents are :

- The control documents (e.g. : flight manual)

- The management documents :• Flight log book• Engine log book (records and provides information

on the engine status).

Maintenance documents

- The current maintenance documents are the following :• Maintenance manual (describes the engine and its

systems and all the maintenance procedures)• Service bulletins (approved by the authorities, and

issued to inform the operators of a modification or aninstruction which affects the operational aspects)

• Service letters (letter sent to inform the operator ofcertain instructions related to the operation of theengine)

• Modification index

- The general overhaul and repair documents :• Overhaul manual• Standard practices manual• Work specification.

- The deep maintenance documents (specific manual).

Identification documents

The identification documents are :

- The current maintenance documents :• Spare parts catalogue (list and reference of all the

spare parts)• Special tool catalogue (tool designations and

references).

- Overhaul and repair documents :• Illustrated parts catalogue (illustrates in detail all the

engine and accessory parts ; only used for generaloverhaul)

• Descriptive list and drawings.

Note : Before all maintenance procedures :- Refer to official documentation- Use the documentation "in a rational way"- Make sure that documentation is up-to-date.




TECHNICAL PUBLICATIONS

DOCUMENTS

OPERATION MAINTENANCE IDENTIFICATION

Overhaulrepair

Currentmaintenance

ManagementControl

Example :Flight manual

Example :- Engine log book

- Spare parts catalogue- Special tool catalogue

- Illustrated parts catalogue- Descriptive list and drawings

CURRENT MAINTENANCE GENERAL OVERHAULREPAIR

DEEPMAINTENANCE

- Maintenance manual- Service bulletins and letters- Modification index

- Overhaul manual- Standard practices manual- Work specification

- Specific manual





TECHNICAL PUBLICATIONS -MAINTENANCE MANUAL

It describes the engine and its systems and all themaintenance procedures.

Layout

This document has been compiled according to therequirements in the American standard "A.T.A. 100" asfollows :

Page numbering (ATA 100)

Description and operation............................from 1 to 99Fault analysis .........................................from 101 to 199Special procedures .................................from 201 to 299Removal .................................................from 301 to 399

Installation .............................................from 401 to 499Cleaning .................................................from 601 to 699Replacement ..........................................from 701 to 799Check, inspection...................................from 801 to 899Servicing ............................................from 1101 to 1199Storage ...............................................from 1201 to 1299Tests ...................................................from 1301 to 1399

Layout of a chapter

0. Introduction1. General2. Purpose3. Complementary documentation4. Breakdown

A. ChaptersB. Page numberingC. Item numberingD. Illustration

5. Effectivity6. Revisions

A. Normal revisionsB. Temporary revisions

7. Use of this manualA. Systematic maintenance operationB. Optional maintenance operationsC. Replacement of modules

8. List of abbreviations

CHAP DESIGNATION

00 Introduction05 Time Between Overhauls and life limits26 Fire protection system70 Standard practices71 Power plant72 Turboshaft engine73 Fuel system74 Ignition system75 Air system77 Engine indicating78 Exhaust system79 Oil system80 Starting83 Accessory gear-box




TECHNICAL PUBLICATIONS - MAINTENANCE MANUAL

OBJECTIVE

- Description / operation of the engine and its systems- Maintenance procedures

LAYOUT

- Chapters- Sub-chapters- Paragraphs

NUMBERING

- Gives the subject treated by the page

CONSULTATION

- Consultation method- Up-dating





TECHNICAL PUBLICATIONS - TURBOMECAENGINE LOG BOOK

Function

This log book is used for :

- Recording all information about the engine, the modulesand the accessories, including the hours and cycles usedand work carried out

- Recording the basic modification standard of the engine.

Contents- Test bed results sheet

- Section A : test certificate and record of modificationsembodied on non modular parts

- Section B : record of modules

- Section C : record of equipment

- Section D : availability state

- Section E : operation, maintenance and servicing

- Maintenance and accessory log cards.

Use of the log-book- Test bed results sheet and section A : completed in the

factory, may not be modified by the operator

- Section B : when a module is replaced, record thereference number, the serial number and the date on theright hand page

- Section C : accessory replacement : when an accessoryis replaced, the details should be entered on the righthand page.

- Section D : TBO : the TBO of a replacement moduleshould be recorded here

- Section E :• "Daily" column : record the daily hours and cycles

• "Total since new" column : record the accumulatedhours and cycles

• "Total since start of life" column : record theaccumulated hours and cycles since the last modularrebuild.

Note : After changing a module the "total since start oflife" column should be returned to zero.

• "Observations" column :Record :- The type of work carried out- The reference, serial N°, hours/cycles and reason

for change of module or accessory replaced- The embodiment of a modification.

• Module/Component log card : record fitting/removaldetails.




TECHNICAL PUBLICATIONS - TURBOMECA ENGINE LOG BOOK

R Désignation / Identity Fabricant - RéférenceManufacturer - Reference

N° SérieSerial No

DateSignature

R Désignation / Identity Fabricant - RéférenceManufacturer - Reference

N° SérieSerial No

DateSignature

R Désignation / Identity FabricantManufacturer

N° SérieSerial No

DateSignature

Référence / Reference

Fabric. / Manuf. Motorist. / Eng. M.h équipt pose

Accy hrs when fitted

Tot. h. moteur / Total eng. hrs

Pose / Fitting Prévi. déposeForecast rmv.

1 - POTENTIEL / T.B.O.

Moteur non modulaireou modules / Nonmodular

engine or modules

Boîte accessoiresAccessory gearboxCompresseur axialAxial compressor

Total

h

EffectuéConsumed

h

DisponibleAvailable

h

2 - VIE LIMITE / LIVE LIMIT

Pièces / Parts

Roue compresseur axialAxial compressor wheel

Total

Cycles

EffectuéConsumed

Cycles

DisponibleTo be run

Cycles

SECTION D

SECTION C

SECTION B

SECTION E

FONCTIONNEMENT / TIME RUNJournalier

DailyCyclesDate

GasGen

T.L.P.T.

H

Total depuis neufTotal since new

Cycles

GasGen

T.L.P.T.

H

Total depuis état de disp.Total since stat. of life

Cycles

GasGen

T.L.P.T.

H

Observations - Travaux effectués - SignatureObservations - Works carried out - Signature





PRODUCT SUPPORT

General

TURBOMECA provides the operator with the trainingand the assistance required to maintain the product in goodoperating condition.

Main aspects of the support

The support covers the following fields :

- Training

- Technical documentation

- Spare part provision

- Technical assistance

- Engine overhaul and repair

- Contracts.

Subsidiaries and support centres

Subsidiaries and support centres have been set up toprovide a world wide support network.




PRODUCT SUPPORT

TRAINING

TECHNICALDOCUMENTATION

SPARE PARTPROVISION

CONTRACTSTECHNICAL

ASSISTANCESUBSIDIARIES ANDSUPPORT CENTRES



For training purposes only© Copyright - TURBOMECA - 2000 MAINTENANCE PROCEDURES

14-MAINTENANCE PROCEDURES

- General .......................................................................... 14.2

- Inspection and check procedures ................................ 14.4

- Removal and installation procedures ......................... 14.52

- Deep maintenance.......................................................... 14.62

- Repair and overhaul ..................................................... 14.64 to 14.65




MAINTENANCE PROCEDURES

MAINTENANCE PROCEDURES - GENERAL

This part is an introduction to the different maintenanceprocedures, which are described in the following pages fortraining purposes only.

These procedures are dealt with in discussion and practicalwork during a training course.

Procedures described

- Standard practices

- Cautions (Cautions, Warning)

- Storage

- Compressor washing

- Oil checks

- Miscellaneous checks

- Borescopic inspection

- Axial compressor inspection

- Operating checks

- Vibration check

- Electrical harness check.

- Permeability check

- Engine removal and installation

- Removal and installation of the accessories

- Module removal and installation

- Repair, general overhaul.

Note : Refer to the maintenance manual and ensure thatit is up to date before carrying out any maintenanceprocedure.




MAINTENANCE PROCEDURES - GENERAL

PROCEDURES

- Definition- Instructions and operating modes

LISTS OF PROCEDURES

- Standard practices- Cautions- Storage- Washing- Miscellaneous checks- Miscellaneous procedures- Removal, installation- Repair- Adjustments

Refer to the maintenance manual beforecarrying out any maintenance procedure.

Note :





STANDARD PRACTICES

General

"Standard practices" are all the common procedures andpractices, required for the maintenance and repair ofengines. These "standard practices" are dealt with in onechapter of the maintenance manual (chapter 70).

They are also dealt with in a specific document, called TheStandard Practices Manual, mainly used by repairers.

Main practices

Standard practices mainly deal with :

- Torque loading

- O'ring seal installation

- Locking of assemblies

- Pipe and union assembly

- Thread insert replacement

- Magnetic seal replacement

- Application of miscellaneous products (loctite, graphitegrease…)

- Repair techniques (exhaust pipe welding, crack stopdrilling…)

- Installation of electrical connectors

- Check and inspection (ex. : fuel/oil dilution check).




STANDARD PRACTICES

LOCKING OF ASSEMBLIES

O'RING SEAL INSTALLATION

THREAD INSERT REPLACEMENT

TORQUE LOADING(torque wrench)

PIPE AND UNION ASSEMBLY

STANDARD PRACTICES

- Manual- Chapter 70 of the maintenance manual





ADVISORY NOTICES

Three types of advisory notice are used in the technicalpublication :

- WARNING

- CAUTION

- NOTE.

Interpretation

WARNING : warns the reader of the possibility of physicalharm (e.g. : wounding, intoxication, electrocution).

CAUTION : warns the reader of the possibility of damagingthe engine or tooling.

NOTE : gives the reader advice on how best to carry out atask.

Examples

WARNING : do not breath the oil fumes. Do not leave oilin contact with the skin.

CAUTION : if the flush is being carried out because ofmetal particles in the oil system, change the filter andthoroughly clean the tank.

NOTE : take the oil sample before carrying out anyreplenishment.

List of the main notices

WARNING :

- Toxicity of engine oil, cleaning products andextinguishing products

- Eye protection

- Fire risk

- Electrical discharge from HE ignition unit.

CAUTION :

- Use of the correct tool

- Use of certain products

- Weak points of the engine or tools

- Tightening torques.

NOTE :

- Oil analysis

- Cycle counting

- Engine storage

- Parameter measuring.




ADVISORY NOTICES

- Toxicity of engine oil and vapours- Toxicity of cleaning products- Toxicity of extinguishing products- Eye protection- Fire risk- Electrical discharge from HE ignition unit :

- electrocution- risks with use in an inflammable

atmosphere

- Titanium part cleaning- Scrapping of O'ring seals- Use of the correct cleaning products- Engine cooling- Engine cleaning after use of

extinguishing product- Orifice protection during removal- Borescope fragility- Tightening torque

- Oil analysis- Cycle counting- Installation of O'ring seals- Engine storage- Insulation measurements- Procedural change with modification

WARNING(physical harm)

CAUTION(possibility of damage)

NOTE(advice)





STORAGE

General

When an engine is not used for a long time, it must beprotected against corrosive agents.

The most efficient protection consists of :

- Washing and protecting the air path by spraying aspecific product

- Housing the engine in a waterproof metal container withdessicant bags.

If there is no container, the engine can be housed in a waterand vapour proof cover with desiccant bags.

Type of storage

- "Long term" storage : procedure which protects theengine for a duration of more than 3 months if the engineis not installed in the helicopter. The engine is theninhibited in the package (in non sealed case or in metalcontainer)

- "Short term" storage : procedure which protects theengine for a duration of less than 3 months if the engineis not installed in the helicopter.

If the engine is installed in the helicopter :• When the engine is not used for less than 7 days,

install the air intake and exhaust blanking devicesand close the cowlings

• When the engine is not used between 7 days and 6months, drain and replace the oil, do a 5' ground runcheck every 7 days

• When the engine is not used for more than 6 months,remove the engine and do the "long term" storageprocedure.

Note : Refer to maintenance manual for storage limits(eg. : 10 years in metal container).




STORAGE

GENERAL

- Protection against corrosive agents- Cleaning, internal and external protection

PROCEDURES

- For engine installed in aircraft (less than 7 days or between 7 days and 6 months)- For uninstalled engines (3 months and more than 3 months)- Internal and external protection- System protection- Inhibiting products- Blanking devices

TYPE OF STORAGE

- "Long term" : duration more than 3 months (storage in a container)- "Short term" : duration less than 3 months (protection cover)

PACKAGE

- In non sealed case- In metal container : procedure, storage and periodic inspections Note : Package of engine, modules and accessories





CLEANING AND PROTECTION

General

Given procedures are applied to clean and protect theengine.

Main procedures

- Internal cleaning and protection (rinsing, washing,cleaning, protection : refer to compressor washing)

- External cleaning and protection

- Procedure after usage of extinguisher

- Procedure to protect the equipment (ex. : water infuel…).

Note : Follow the instructions for the use of the cleaningproducts.

Refer to maintenance manual, chapter 71.




CLEANING AND PROTECTION

GENERAL

- Cleaning- Protection

NOTES

- Precautions- Ref : Maintenance manual chap. 71

PROCEDURES

- For internal parts (refer to compressor washing)- For external parts- For equipment





COMPRESSOR WASH

General

Compressor washing avoids dirt accumulation andcorrosion in the air path, particularly the compressor.

Types of treatment

- Washing and/or rinsing : removal of corrosive deposits(particularly salt deposits)

- Cleaning : removal of deposits likely to accumulate onthe internal parts

- Protection : protection of surfaces against corrosion.

Frequencies

- Washing : frequently in salt laden atmosphere

- Cleaning : periodic inspection before storage, if necessary

- Protection : before storage or in case of long grounding.

Note : Frequencies depend on operating conditions.

Procedures

Compressor washing mainly consists of spraying a suitableproduct in the air intake during one or several ventilationsequences (water, Ardrox…).

Note : Many aircraft are fitted with a compressor washingsystem. Washing and cleaning during a ventilationis considered the most efficient.




COMPRESSOR WASH

GENERAL

- To avoid dirt accumulation and corrosion in the air path, particularly the compressor- Preventive operation

PROCEDURES

- Spraying a suitable product in the air intake during one or several sequences- Spraying device- Products (water, ardrox)

TYPES OF TREATEMENT

- Washing and / or rinsing : removal of corrosive deposits (particularly salt deposits)- Cleaning : removal of deposits likely to harm the internal parts- Protection : protection of surfaces against corrosion

FREQUENCIES

- Washing : frequently in salt laden atmosphere- Cleaning : at periodic inspection before storage, if necessary- Protection : before storage or in case of long grounding





OIL SYSTEM SERVICING

This part summarizes the maintenance procedures for theoil system.

Particular instructions

Maintenance manual instructions must be followed in thefollowing cases :

- Oil specification change

- Mixing with a product which is not in conformity withoil specification

- Oil life limitation

- Oil filter blockage

- Dilution.

Particle sampling

- Particle sampling procedure with magnetic plugs

- Particle interpretation

- Particle analysis.

Spectrometric oil analysis

- Purpose of the spectrometric analysis

- Sampling frequency

- Sampling procedure

- Word definition (ppm, concentration, contaminationspeed, thresholds…)

- Result interpretation (warning threshold and immediatestop table).

Oil change

- Drain conditions (blockage, particles, before removal)

- Drain procedure (engine through magnetic plugs, coolingunit and tank according to aircraft manufacturer'sprocedure).

Oil filling

- Aircraft manufacturer's procedure.

Oil system flushing

- Conditions (oil specification change, contamination,life limitation…)

- Procedure (draining, filling, ground run, draining, filterinspection, final filling).




OIL SYSTEM SERVICING

PARTICULAR INSTRUCTIONS

- Conditions- Procedure

- Oil specification change- Mixing- Life limitation- Filter blockage- Oil dilution

SPECTROMETRICOIL ANALYSIS

- Purpose- Frequency- Procedure- Definition- Interpretation

OIL CHANGE

- Conditions- Procedure

- Tank (aircraft manufacturer's procedure)

PARTICLE SAMPLING

- Procedure- Interpretation- Analysis

OIL SYSTEM FLUSHING OIL FILLING





MISCELLANEOUS PROCEDURES

This part only mentions procedures which are part of themaintenance activity.

Introduction into service

The introduction into service includes :

- The preparation of an engine delivered in a wooden case

- The preparation of an engine delivered in a metalcontainer

- Installation in the aircraft

- A ground run check.

Adjustments

The engine is designed to require no current maintenanceadjustments.

Refer to corresponding pages and to maintenance manualfor more details.

Particular instructions

- Fuel : follow particular instructions in case of use of analternative fuel and additives and in case of filter blockage

- Foreign Object Damage (FOD) : procedure accordingto the nature of the body ingested (direct visual inspection,borescopic inspection, vibration check)

- Exceeding of limits : particular instructions in case oftemperature, torque and speed exceedance, and in caseof engine flame out, compressor surge

- Heavy landing

- Damage during transport.

Treatment after use of extinguishers

The treatment required after use of a fire extinguisher or anaccidental operation of the extinguishing system, minimisescorrosion by extinguishing products.

The treatment is different according to the conditions ofthe extinguisher use and to the extinguishing products(CO

2, foam, powder, halon…).




MISCELLANEOUS PROCEDURES

INTRODUCTION INTO SERVICE

- Preparation of an engine delivered in a wooden case- Preparation of an engine delivered in a metal container- Ground run check

PARTICULAR INSTRUCTIONS

- Fuel- Foreign Object Damage- Exceeding of limits- Heavy landing- Damage during transport

ADJUSTMENTS

- The engine is designed not to require current maintenance adjustments. (refer to maintenance manual)

TREATMENT AFTER USEOF EXTINGUISHERS

- Normal or accidental use- Treatment to reduce corrosion by extinguishing products- Treatment according to use conditions (fire or accidental use) and to the extinguishing product (CO2, foam, powder, halon...)






General

Borescopic inspection allows the inspection of the internalparts which are not accessible without disassembly. Thistype of inspection uses a special tool which allows a directvisual inspection of the parts.

Borescopic inspection can be carried out with the enginein or out of the helicopter, and on removed modules.

Combustion chamber borescopic inspection

To do this inspection, it is necessary to remove an igniterplug.

The combustion chamber inspection is done by enteringthe borescope through the igniter plug orifices

Borescopic inspection of the gas generator turbine

It allows the visual inspection of the nozzle guide vane andthe wheel (blades, blade roots...). The inspection is carriedout using a flexible borescope and a guide in one of theigniter plug orifices.





- Inspection of the internal parts which are not accessible without disassembly

- Use of special tools

- Borescopic inspection with the engine in or out of the helicopter

- Rotation of the N1 rotating assembly through one of the accessory drives or the compressor

- Rotation of the N2 rotating assembly either through the rotor (engine on aircraft) or through the main power drive (engine removed)

Combustionchamber and turbine





AXIAL COMPRESSOR INSPECTION

Function

This check permits the detection of dents, cracks anderosion.

Conditions

This check can be carried out with the engine installed oruninstalled, and on a removed module.

Procedures

- Visual inspection of the blades

- Erosion inspection using a gauge.

Visual inspection

The blades must be inspected for cracks, folding, pitting,dents and nicks.

Erosion inspection

This is carried out by placing the template on the inletcone, with the indicator plate butted up against the bladeroot. The calibrated gauge is then introduced betweenblade and template to measure the erosion.

Criteria

The maintenance manual details the procedure to befollowed, the number of dents permitted, their max depthand the max permitted erosion value. No cracks permitted.

Refer also to the maintenance manual for the reworkprocedure of the axial compressor 1st stage blades.




AXIAL COMPRESSOR INSPECTION

VISUAL INSPECTIONEROSION INSPECTION

D

L

2 mm (0.0787 inch)

3 mm (0.1181 inch)D

CB

A

Max limitsector D = 3 mm

Max limitsector A = 1 mm

GAUGE

TEMPLATE





FREEWHEEL CHECK

On single engine version :

Function

To check the oil level (single engine).

Conditions

This check can be carried out engine installed or removedfrom the helicopter.

Procedure

The free wheel is equipped with two plugs, for oil levelcheck and oil draining.

The filling port must be correctly positioned.

On some versions, the oil supply is assured by means of alubricating jet located inside the accessory gearbox.




FREEWHEEL CHECK

OIL FILLINGPORT

OIL LEVEL CHECKPOSITION :2 O'CLOCK





CHECK OF INJECTION FUEL INLET UNION

Purpose

To check for leaks of fuel or P2 air.

Conditions

This check is carried out in the aircraft during a ground run.

Procedure

With the blanking screw removed and the engine runningthere must be no leaks from the orifice. In the event of leaksthe seals must be replaced and a further check carried out.




CHECK OF INJECTION FUEL INLET UNION

LEAK CHECK POINT(normally blanked)

"O" RINGCOPPER

SEAL





VIBRATION CHECK

Conditions

The vibration check is systematically made at regularintervals and in the following cases :

- After any failure due to an excessive vibration level

- In case of doubt about the engine vibration level

- After a modular maintenance operation.

Procedure

This check is carried out with a vibration sensor fixed onthe engine (on the HE unit support or on the rear flange ofthe turbine casing). The accelerometer measures thevibration generated by the gas generator and the powerturbine.

There are many vibration checking sets (refer to themaintenance manual).




VIBRATION CHECK

VIBRATIONSENSOR

REAR SENSORBRACKET

(on the HE unit supportor on the rear flangeof the turbine casing)

VIBRATIONTEST SET

Examples of a vibration measurement system.(Other systems can be used)





ENGINE POWER CHECK

Conditions

An engine power check can be carried out in flight byrecording certain parameters and plotting them on a graph.For further details see the flight manual.




ENGINE POWER CHECK

t0

Tq %

ZpNR

N1

Example of a diagram with an operating point shown with dotted lines

GOOD

BAD





TORQUE TRANSMITTER AND LOW OILPRESSURE SWITCH CHECK

Purpose

To check the operation of the torque transmitter and thelow oil pressure switch.

Conditions

The component to be checked must be removed from theengine.

Procedure

The check can be carried out either using the Turbomecatest set or a Barfield pump.

Torque transmitter : the pressure corresponding to 100 %torque is written on the module 5 log card. With thetransmitter fitted on the test set the pressure is raised to thelog card figure and the indication can then be checked andadjusted.

Low oil pressure switch : with the unit fitted on the testset the pressure can be increased & decreased to check atwhat pressure the switch makes & breaks.




TORQUE TRANSMITTER AND LOW OIL PRESSURE SWITCH CHECK

TEST SET

TORQUE TRANSMITTER

LOW OIL PRESSURESWITCH

DIGITALINDICATOR

REFERENCECAPSULE

COCK

CONTROL

BARFIELD PUMP





IGNITION SYSTEM CHECK

Purpose

To check the operation of the engine ignition system.

Conditions

This check can be carried out with the engine installed oruninstalled. The test set requires a 28 volt supply.

Procedure

The test set is connected to the HE unit input connector.Selection of "ignition" on the test set supplies the HE unit,a light indicates a complete circuit and the igniters operate.

Note : The same test set can be used for testing the startinjector electro-valve.




IGNITION SYSTEM CHECK

TEST SET

28 VDCSUPPLY

TO H.E. IGNITION UNIT





OVERSPEED SYSTEM CHECK

Purpose

To confirm the integrity of the overspeed system.

Conditions

The check can be carried out engine installed or uninstalled,tacho box installed or uninstalled.

Procedure

With the test set supplied with 28 V and connected to thetachometer box signals of overspeed frequency can besupplied to the box to check its operation.

Note : The same test set can be used to check insulationand resistance of the overspeed pick-up probe.




OVERSPEED SYSTEM CHECK

TEST

TACHOMETER BOX

TEST SET





COMPRESSOR BLEED VALVE OPERATIONCHECK

Purpose

To check that the bleed valve operates at the correct RPM.

Conditions

This check can only be carried out with the engine runningat high RPM, perhaps necessitating a take-off.

Procedure

For the electro pneumatic valve check that the N1 threshold(opening and closing) is correct.

For pneumatic valves, the threshold is function of altitudeand atmospheric temperature. It is necessary to refer to agraph in the maintenance manual.




COMPRESSOR BLEED VALVE OPERATION CHECK

N1

Z = 2000 m

Z = 0

t0

Example of curve showing the N1 threshold as a function of t0 and Z.(pneumatic bleed valve)





OIL PRESSURE CHECK

Purpose

To accurately check the engine oil pressure in case ofdoubt, after a module change or after assembling a repairedor overhauled engine.

Conditions

Engine installed & running, the pressure is checked at 2points using a calibrated pressure measuring tool.

Procedure

Connect the measuring tool to the test point, start theengine and allow it to warm up to the normal operatingtemperature. Set the RPM at 85 % then read the temperature& pressure.

Plot the temperature & pressure on the graph in themaintenance manual to see if the pressure is withintolerance.

Note : There are several graphs to allow for different oilviscosities.




OIL PRESSURE CHECK

t°

P

Example of graph to check oil pressure for a given oil specification on a given tapping point.





START INJECTOR AND IGNITER PLUGPENETRATION CHECK

Conditions

In the event of starting problems on replacement of a plugor injector the penetration of the plug and injector must becalculated and adjusted using spacers and seals.

Procedure

It is necessary to measure the length under the head of theinjector and igniter and then measure the distance from theturbine casing face to the mixer unit, using a special gaugesupplied by Turbomeca. Using the figures thus obtained,and the calculation table in the maintenance manual, thethickness and quantity of spacers and seals can be calculated.

Note : There must always be a seal against the face of theinjector/igniter and against the face of the turbinecasing.




START INJECTOR AND IGNITER PLUG PENETRATION CHECK

MEASUREMENTS OF THE INJECTORSAND IGNITER PLUGS PENETRATION

IN THE COMBUSTION CHAMBER

STARTINJECTOR

IGNITERPLUG

GAUGE

X'

C' L'

e'

L

X eC

COMBUSTIONCHAMBER





PERMEABILITY CHECK

Conditions

A permeability check of the fuel injection wheel must becarried out during periodic servicing. It may also becarried out in case of suspected problems.

Procedure

The permeability test tool is connected to the injectionwheel inlet union ; it is then filled to the top with water.

After opening the cock at the inlet to the engine the timetaken for the water level to pass between the two marks Aand B on the tube is measured. A table in the maintenancemanual shows the action to be taken according to the timerecorded, e.g. t < 8 sec. - next check in 450 hours.t > 11 sec. - carry out wheel cleaning procedure.




PERMEABILITY CHECK

A

B

MEASUREMENT OFFLOWING TIME BETWEEN

A AND B

FUNNEL

COCK

INLET UNION





STATIC DROOP CHECK AND ADJUSTMENT

This is mandatory check in the event of an anomaly suchas :

- drift of max N1

- drift of NR

- N1 difference between 2 engines.

Procedure

The procedure is carried out with the engine running onground and is defined in the Maintenance Manual.

This check verifies the relationship between N1, theanticipator angle at min. pitch end the NR. The procedurethen determines the necessary action. This may requireadjustment of the temperature compensating bulb or itsreplacement if the adjustment limit is reached.

It is particularly important to use high precision digitalindicators for the readings during the check.

Note : Any adjustment of the temperature bulb must berecorded in the engine log book to ensure that themaximum adjustment limit is not exceeded.




STATIC DROOP CHECK & ADJUSTMENT

B = 0° B = 10° B = 30°B = 20°

322 325 330 335 340 345

75

77

79

81

82

83

87

N1 %

346.2347.7

89

85

350 355 358

82.3

81.1

22°

NR min rpmBEFORE TEMPERATURE COMPENSATOR ADJUSTMENT

AFTER TEMPERATURE COMPENSATOR ADJUSTMENT





CHECK OF NR AND OF N1 MATCHING

This check verifies the instrumentation and the adjustmentof the components of the fuel flow control system.

The check procedure is defined in the Flight Manual.

Note : It is particularly important to use high precisiondigital indicators.

Any anomaly will be either an indication anomaly(indication of NR, N1 or torque) or incorrectly riggedcontrols e.g. anticipator or an anomaly in the F.C.U.(temperature compensation bulb).

Normally the first action to take is to carry out a staticdroop check.




CHECK OF NR AND OF N1 MATCHING

NR N1 N1

TEMPERATURECOMPENSATING CAPSULE





CHECK OF MAX. N1

The max. N1 check ensures that the maximum enginepower is available.

The check procedure is described in the Flight Manual.

Generally the check will show, according to the enginetype :

- Either that the engine reaches the max N1 stop

- Or that the stop is beyond the normal max N1.

This check may identify an anomaly such as fuel systemblockage, leak in the fuel system, drift at the fuel controlcaused by the temperature compensator.

Note : This check must be carried out using very accurateinstruments such as digital RPM indicators.




CHECK OF MAX N1

-50 -40 -30 -20 -10 0 10 20 30 40

Correct adjustment range

Fuel temperature °C50

104,8

103,8

TEMPERATURE COMPENSATINGCAPSULE (PRE-MOD TU183)

BIMETALLIC CORRECTOR(POST-MOD TU183)

FCU SEEN FROMTHE FRONT

MARK

TEMPERATURE CAPSULEADJUSTING SCREW

(ADJUSTMENT, IF NECESSARY)N1 max %





CYCLE COUNTING

Cycle counting enables the calculation of usage of lifelimited parts such as compressors, injection wheel andturbine wheels.

Two types of cycles must be counted : gas generator cyclesand power turbine cycles.

Gas generator cycles

There are two formulas which can be used, therecommended method and the lump method.

The recommended method takes into account the max N1(K1) and min N1 (K2) reached, as well as the number ofpartial cycles (n) during the flight.

The lump method takes into account only the partial cyclesduring the flight.

A partial cycle corresponds to a significant decelerationfollowed by a significant acceleration without stoppingthe engine.

Power turbine cycle

For the power turbine one flight equals one cycle.

Refer to the maintenance manual, chapter 5 for full detailsof the cycle counting including the exclusions andobligations.




CYCLE COUNTING

HighestN1 %

K1

10099989796959493

10.90.80.70.650.60.550.5

K2

8584838281

8079787776

757473727170

<70

0.05

0.15

0.15

0.1

TIME

N1%

Start Stop

Recommended method

CALCULATE N = K1 + nK2

Where : N = Number of cyclesK = Number from chart for highest N1n = Number of accelerations

K2 = Number from chart for each accel.

Thus : N = 0.8 + 1 x 0.1 = 0.9 Gas Gen cycles

Lump method

CALCULATE N = 1 + n x 0.15

Thus : N = 1 + 1 x 0.15 = 1.15

LowestN1 %

EXAMPLE OF A FLIGHT PROFILE





REMOVAL AND INSTALLATION OF THEPOWER PLANT

Removal - Installation

The procedure for engine installation in the airframe is theresponsibility of the aircraft manufacturer. The removaland installation procedures are therefore described in theaircraft maintenance manual. Nevertheless, this sectiondeals with these procedures generally for training purposes.

During installation, some points must be checked, suchas :

- Before installation :• Check the engine general condition (casings,

harnesses, pipes, accessories…)• Check the free rotation of the rotating assemblies• Check the condition and attachment of equipment• Remove the various blanks.

- After installation :• Do a general check (attachments, levels, various

connections…)• Do a ground run (starting, operation, stop, ventilation)• Do a flight test.

Installation of the engine on the support stand

The installation procedure requires the use of a specialsling and support.

The engine is secured on its rear support by a clamp and onits front support by bolts.

The engine can be put in the vertical position by means oftwo struts mounted at the front of the support stand.




REMOVAL AND INSTALLATION OF THE POWER PLANT

REMOVAL - INSTALLATION

- Aircraft manual- Checks :

• Before installation• After installation

INSTALLATION ON STAND

- Horizontal position- Vertical position

Lifting tool

Trolley Support stand

Pulley bloc





REMOVAL AND INSTALLATION OF THEACCESSORIES

This part summarizes the accessories which can be replacedon the flight line (Line Replaceable Units).

List of the accessories


The table gives :

- The accessory identification

- The method of attachment

- Remarks.

Removal and installation procedure

Refer to maintenance manual. In a training course,procedures are dealt with in a video course and practicalsessions.

Caution - Warning - Note

Strictly follow the maintenance manual instructions :ignition unit, oil…

Refer to ADVISORY NOTICES in this chapter.

Consumable or repairable components

The accessories are considered as either consumable orrepairable.

Some accessories which are considered as consumable :fire detector, start injector, igniter plug, ignition unit,speed sensors, filters, strainers, magnetic plug…




REMOVAL AND INSTALLATION OF THE ACCESSORIES

LIST OF ACCESSORIES

- Identification- Method of attachment- Remarks

PROCEDURES

- Maintenance manual

PRECAUTIONS

- Note- Caution- Warning

CONSUMABLE OR REPAIRABLECOMPONENTS

- Consumable components- Repairable components- TBO / on-condition





ATTACHMENT

Bolted onto the accessory gearbox

Two bolts on protecting tube rear mountingflange

Ring of bolts on the power turbine casing

Standard unions

4 bolts on combustion chamber mountingflange

3 bolts on exhaust pipe mounting flange

REMARKS

1S, 1K, 1E

ACCESSORY

Front attachment

Rear attachment

Exhaust pipe

Pipes

Front lifting bracket

Rear lifting bracket

REMOVAL AND INSTALLATION OF THE ACCESSORIES

List of the engine accessories.




ACCESSORIES

Oil pumps

Oil filter

Pre-blockage indicator

Oil pressure transmitter

Low oil pressure switch

Electrical magnetic plug assy.

Oil cooler

Magnetic plugs

Strainers

ATTACHMENT

3 bolts on the accessory gearbox

Cover & bolt

Screwed into the filter base

Screwed into the filter base

3 bolts on the filter base

Screwed into the housing

Bayonet type attachment

1 bolt

REMARKS

Installed in the aircraft

Rear bearing strainer in pump inlet

ACCESSORIES


ATTACHMENT

Clamp

REMARKS

REMOVAL AND INSTALLATION OF THE ACCESSORIES (CONTINUED)

List of oil system accessories.

List of air system accessories.






List of fuel system accessories.

ATTACHMENT

2 half-shells + clamp

2 screws

Screwed into the FCU

Threaded bowe

Installed on start electro-valve

2 bolts on turbine casing

Installed on overspeed and drain valve

2 screws on the combustion chamber casing

Screwed into the combustion chamber casing

Installed on ejector

Installed on protection tube

ACCESSORIES

Fuel Control Unit

Fuel filter

Blockage indicator

LP fuel filter

Start purge valve

Overspeed & drain valve

Pressurazing valve

Start injectors

Combustion chamber drain valve

Astatic Valve

Ejector

REMARKS

Don't forget N2 drive coupling

1S, 1E, 1K

1S , 1E

1S, 1E

1S, 1E





List of indicating system accessories.

ATTACHMENT

Two screws

Screwed into casing

2 bolts on Acc. gearbox

Fitted in aircraft

Thermocouples screwed into casing

Screwed into casing

ACCESSORIES

N1 & N2 speed sensors

Torque transmitter

N1 & N2 tacho-generators

Tachometer box

Thermocouple harness

Overspeed sensor

REMARKS

1S only

Adjustable except 1S, 1E

N2 optional

Fragile probes

Locating pin

List of starting system accessories.

ATTACHMENT

Collar & clamp

Screws on a bracket

2 screws on the combustion chamber casing

Threaded union at each end

ACCESSORIES

Starter

Ignition unit

Igniter plug

Ignition cables

REMARKS

Supply by a/c manufacturer

Post mod TU 271A





REMOVAL AND INSTALLATION OF ENGINEMODULES

Modular designThe engine is of modular construction. This conceptavoids the return of the complete engine to a specializedworkshop and thus provides a higher operationalavailability and a reduction of maintenance costs.

Module replacementEach module is a unit which can be replaced withoutbalancing or adaptation work.

However, some precautions must be taken when replacinga module. This page mentions the main points related tothis question :

- Reasons for module removal• Inspection (access to some components)• Replacement

- Module identification• Identification plate on module• Compatibility table• Engine log book

- Removal and installation conditions• Engine installed (or uninstalled)• Installation on working stand• Particular position (horizontal or vertical)

- Tools• Standard tools• Special tools

- Inspection after replacement• Ground run check• Condition checks• Functional checks• Performance checks

- Module follow-up• Engine log book and module log card

- Interfaces• Intermodular parts• Equipment• Mounting.

Note : Refer to maintenance manual.




REMOVAL AND INSTALLATION OF ENGINE MODULES

MODULE REPLACEMENT

- Reasons- Identification- Conditions- Tools- Inspection after replacement- Module follow-up- Interfaces

MODULE M02

M02 / M031 TIE BOLT NUT &1 RING OF BOLTS

MODULE M03 MODULE M04

MODULE M05MODULE M01

M01 / M051 RING OF BOLTS

M02 / M014 BOLTS

M03 / M041 RING OF BOLTS





DEEP MAINTENANCE

Deep maintenance, also called 3rd line or H Level, coverscertain defined operations to repair an engine, module oraccessory by replacing some parts without necessitatingmachining or test bed checking.

It requires specific training, tooling and approveddocumentation.

The following operations are possible :

- Fuel injection manifold cleaning

- Replacement of the gas generator turbine casing

- Replacement of the gas generator rear bearing

- Replacement of the nozzle guide vane

- Operations on components of module 3 e.g. cleaning ofthe turbine shaft.

In the future :

- Replacement of the axial compressor

- Replacement of the power turbine and/or the bearings

- Any other operation that may be dearmed necessary.




DEEP MAINTENANCE

AXIALCOMPRESSOR WHEEL

GAS GENERATORTURBINE CASING

REAR BEARING

NOZZLEGUIDE VANE

INJECTIONMANIFOLD

GAS GENERATORHOLLOW SHAFT

POWER TURBINE





REPAIR AND OVERHAUL

Overhaul

Overhaul is a maintenance operation which is carried outwhen the engine (or module) has reached the end of itsTBO, either operating hours or cycles.

The overhauled engine (or module) is then put back intoservice with zero hours for a new TBO.

Repair

Repair is a maintenance operation which must be carriedout when the engine (or module) is unserviceable.

After a repair (IRAN), the engine (or module) is put backinto service with its old TBO.

Note : TBO : Time Between Overhaul

IRAN : Inspect & Repair As Necessary.

Main procedure steps

- Engine reception

- Disassembly

- Cleaning

- Inspection

- Investigation

- Repair

- Installation (of engine and accessories)

- Tests

- Delivery.




REPAIR AND OVERHAUL

TESTS

DELIVERY

ENGINERECEPTION

DISASSEMBLY - REPAIRACCESSORY ASSEMBLY

REPAIR

INVESTIGATION

DISASSEMBLY

INSPECTIONCLEANING

ENGINE OR MODULEAT THE END OF TBO

OR FOR REPAIR

REPAIR AND OVERHAULSHOP

ENGINE OR MODULE DELIVERYAFTER OVERHAUL WITHFULL TBO, OR REPAIRED

ENGINE ASSEMBLY



For training purposes only© Copyright - TURBOMECA - 2000 FAULT ANALYSIS AND TROUBLE SHOOTING

15-FAULT ANALYSIS ANDTROUBLE SHOOTING

- Fault analysis ................................................................ 15.2

- Trouble shooting ........................................................... 15.32 to 15.47




FAULT ANALYSIS AND TROUBLE SHOOTING

Fault analysis

The faults analysed in this chapter concern :

- The bare engine

- The oil system

- The air system

- The fuel system

- Engine control

- Engine indicating

- Starting

- The electrical system

- The engine installation.

FAULT ANALYSIS

General

Fault analysis is based on a school hypothesis which willbring about a better knowledge of the engine and willprepare the technician for all events.

Fault analysis involves finding the effects of a givenfailure, even if it is unlikely to happen or results fromparticular circumstances.

During a training course, each case is commented on anddiscussed with the trainees.

The analysis can be made at the end of each chapter or inthe section devoted to maintenance.




FAULT ANALYSIS

FAILURE HYPOTHESIS(anomalies)

EFFECTS(symptoms)

OIL FILTER

PARTIAL BLOCKAGE

PRE-BLOCKAGE INDICATORAND PRESSURE DECREASE

COMPONENT

HYPOTHESIS (or chosen case)

EFFECT (S)

Example :





Foreign object ingestion

The damage of course depends upon the object ingested.

The effects can be : power loss, vibration and in theextreme, engine shut-down.

Fuel injection system

A partial blockage can cause control instability, startingdifficulties, and loss of power (max N1 unobtainable).

Turbines

Erosion of the blades causes a loss of power, and corrosionof the blades causes reduced strength of the components.

Blade creep can cause rubbing which causes abnormalnoises and a short run-down time.

In the event of blade breakage, the broken parts areretained by the containment shield.

FAULT ANALYSIS - BARE ENGINE (1)

The air path

Dirt in the air path causes a reduced air flow and thusreduced power with a higher gas temperature and a reducedsurge margin.

Compressor

Two main problems :

- Erosion : it has the same effect as dirt with reducedstrength of the components

- Corrosion : it also causes reduced strength of thecomponents.

Combustion chamber

According to the combustion chamber anomaly(deformation, cracks…) : starting difficulties, overheat,instability of control system or, in the extreme, flame out.





AIR PATH

- Dirt

COMPRESSOR

- Erosion- Corrosion

AIR INTAKE

- Foreign object ingestion

TURBINES

- Erosion, corrosion- Blade creep- Blade breakage

- Deformation- Cracks

FUEL INJECTION SYSTEM

- Partial blockage

COMBUSTION CHAMBER





Abnormal wear of the bearings and gears causes oilcontamination which can be detected by magnetic plugsand by oil analysis. More serious damage will causevibration and possibly an accessory drive failure.

Power transmission

A failure of the power shaft causes overspeed and automaticshut-down (twin-engine version).

Imbalance of the shaft will cause vibration.

Sealing

An internal seal leakage causes either a fluid or gas leak ;consequences according to the system concerned.

Any external leak is generally visible.


Exhaust system

Any obstruction or damage to the exhaust system affectsthe engine operation : performance drop, tendency tosurge...

Bearings

Abnormal wear causes oil contamination, detected by themagnetic plugs and the oil analysis.

A bearing failure causes vibration, instability of controland performance drop. A failure or major damage can alsocause engine hang up during start or blockage of therotating assembly.

Accessory drive

A failure of the accessory drive shaft will cause an engineshut-down (oil and fuel pump stop...).

A failure of one accessory drive shaft will cause an effectaccording to the accessory concerned.





BEARINGS

- Wear- Failure

EXHAUST SYSTEM

- Deformation- Obstruction

ACCESSORY DRIVE

- Accessory drive shaft failure- Accessory shaft failure- Wear of gears and bearings

SEALING

- Internal leak : Gas, air, oil, fuel- External leak

POWER TRANSMISSION

- Failure- Imbalance





If the pump pressure relief valve is jammed :

- Open : loss of pressure

- Closed : dormant fault.

Cooling unit

If the cooling coil is obstructed, the flow is ensuredthrough the by-pass valve and causes an increase of oiltemperature.

Note : In case of a pressure drop being confirmed by theindicating system, the engine should be shut-downto prevent more serious damage. An increase ofpressure also indicates a fault in the system(obstruction of jets for example).

FAULT ANALYSIS - OIL SYSTEM (1)

Oil tank

When the oil level is too high, the expansion volumebecomes insufficient, and could cause a leak through theair vent.

When the oil level is too low, there is a risk of insufficientlubrication (the loss of pressure is obviously indicated).

Oil filter

A partial blockage is indicated by the pre-blockageindicator.

When a complete blockage occurs, the lubrication isensured through the by-pass valve, with a risk of systemcontamination.

Oil pumps

A drive shaft failure causes a rapid pressure drop andlubrication failure, with cockpit indication.

The seizing of a pump causes shaft overtorque with the riskof failure.





COULING UNIT

- Cooling coil obstructed

OIL FILTER

- Partial blockage- Complete blockage

OIL PUMPS

- Drive shaft failure- Pump seizing- Pressure relief valve : open, closed

OIL TANK

- Oil level too high- Oil level too low






Internal supply

A local lubrication problem results in a rather quickprocess of deterioration.

It can be detected by abnormal pressure and/or temperature,by particles on magnetic plugs or by the oil samplinganalysis.

Breathing

The obstruction of a breathing line (or anomaly of thecentrifugal breather) may cause overpressure, lubricationproblem, or a leak through the sealing system…

The obstruction of the general air vent causes foaming inthe tank.

Sealing anomaly

An "external" leak is indicated by a visible leak andincreased oil consumption.

An "internal" leak causes an oil leak into the air system,increased consumption, pressure fluctuations, smoke…

Oil contamination

It is already the consequence of an anomaly. Example :fuel dilution of the oil, oil contamination, particles onmagnetic plugs or in the filter, oil sampling analysis results(out of tolerance).





BREATHING

- Breathing line obstruction- Centrifugal breather- Air vent line obstruction

OIL CONTAMINATION

- Dilution- Contamination- Particles on magnetic plugs- Oil sampling analysis results

SEALING ANOMALY

- "External" sealing- "Internal" sealing

INTERNAL SUPPLY

- Local anomaly (obstruction of jet)





FAULT ANALYSIS - AIR SYSTEM

Internal pressurisation system

Any anomaly (obstruction, abnormal clearance) will resultin operating problems :

- Internal oil leak (as labyrinth pressurisation is affected)

- Local overheat (as the system is used to cool the internalparts)

- Loss of power if too much air is tapped.

Power turbine bearing pressurisation

Breakage or obstruction of the P2 air pipe. The labyrinthsare therefore not pressurised :

- Oil leak from hot section

- Consumption

- Smoke emission.

Air tappings for the aircraft

If the air supply is obstructed : refer to aircraft systemconcerned.

If too much air is tapped, it affects the engine performance(W, t4, CH…).

FCU air supply

A leak, breakage or clogging of the restrictor will give anincorrect signal to the FCU affecting the engine accelerationand deceleration (according to version). A complete lossof the pressure will cause very low N1.

Start injector supply

If P2 air tapping is obstructed : Starting problems.

Injector ventilation ball valve

If the valve sticks open this can cause a leak of fuel into theair system and cause starting difficulty.

If the valve sticks closed there will be no injector ventilation,causing injector clogging.


If the valve remains open, it causes a permanent airdischarge and a decrease of available power.

If the valve remains closed, it can lead to engine surge atlow N1 speeds.




FAULT ANALYSIS - AIR SYSTEM

A B

- Valve jammed "open"- Valve jammed "closed"

COMPRESSORBLEED VALVE

- Valve remains "open"- Valve remains "closed"

INTERNAL PRESSURISATIONSYSTEM

- Obstruction- Abnormal clearance- Leak

FCU AIR SUPPLY

- Leak- Broken pipe- Obstruction

POWER TURBINE BEARINGPRESSURISATION

- Broken pipe- Obstruction

- P2 air tapping blockage

START INJECTOR SUPPLY

INJECTOR VENTILATIONBALL VALVE

- Air supply anomaly- Excessive tapping

AIRCRAFT AIRTAPPINGS





FAULT ANALYSIS - FUEL SYSTEM (1)

Aircraft fuel system

An aircraft fuel system anomaly will cause an incorrectsupply to the engine fuel system.

The effects depend upon the anomaly. For example :

- Reduced performance

- Starting difficulties.

Fuel pump

Total failure (i.e. : drive shaft breakage) : engine shut-down and/or no start.

- Pressure relief valve jammed closed : dormant fault,overpressure hazard

- Pressure relief valve jammed open : reduced performanceor even engine shut-down

- Drive shaft seal leak : fuel leak from the drain.

Fuel filter

In case of partial blockage : indication by the pre-blockageindicator.

In case of blockage : by-pass flow with possible fluctuationsof engine ratings.

- By-pass valve jammed closed : dormant fault

- By-pass valve jammed open : by-pass flow with systemcontamination.





AIRCRAFT FUEL SYSTEM

- Fuel supply to the engine fuel system

FUEL FILTER

- Partial blockage- Blockage- By-pass valve (jammed open or closed)

FUEL PUMP

- Total failure (shaft breakage)- Pressure relief valve (jammed open or closed)- Shaft seal leak






Start electro-valve

Electro-valve : the valve remains closed, no supply to theinjectors, no start.

Pressure switch : if the pressure switch does not operate,the re-injection prohibit function is lost. If the switchcontact is failed, no supply to the electro-valve and thereforeno start.

Start injectors

Clogging : starting difficulties or no starting.

Incorrect penetration of injectors : starting difficulties(clogging or deterioration of injectors).

Loss of ventilation : clogging after a certain operatingtime.

Note : Starting with only one injector operative is possible.

Overspeed and drain valve

Pressurising valve jammed "closed" : no supply to theinjection wheel and therefore no start ; there is however afuel supply to the injectors which causes a slight gastemperature increasing.

Pressurising valve jammed "open" : premature fuelsupply to injection wheel causing difficult ignition.

Dual valve : no start if the valve remains in "drain"position, clogging of the injection wheel distributor, if itremains in "injection" position.

Overspeed electro-valve inoperative : no shut-down incase of power turbine overspeed.

Fuel injection wheel

Insufficient sealing : internal fuel leak, possiblecontamination of P2 air and coking of internal parts.

Clogging of the fuel distributor : fuel flow limited andtherefore max N1 speed unobtainable.

Note : Refer to maintenance manual for check procedureand corrective action.





START INJECTORS

- Blocked- Incorrect penetration- No ventilation

OVERSPEED AND DRAIN VALVE

- Pressurising valve :

- Dual valve anomaly- Overspeed electro-valve inoperative

• jammed "open"• jammed "closed"

INJECTION WHEEL

- Leak- Clogging

START INJECTOR ELECTRO-VALVE

- Solenoid - Pressure switch





FAULT ANALYSIS - CONTROL SYSTEM (1)

Engine control lever

Breakage (or disconnection) of the linkage : the FCUlever remains in its initial position. Manual control is notpossible for starting, stopping or emergency.

Seizing of the mechanism (or of the valves) : more forcerequired to move the control lever.

Incorrect adjustment of the lever : the control leverposition does not correspond to the FCU lever position.Effect depending upon maladjustment (eg : starting orshut-down difficulties).

Anticipator control

Breakage of the collective pitch FCU mechanism : thegoverning system operates on one static droop line.Therefore no droop compensation. In twin-engineconfiguration, this will result in an N1 desynchronisationof the engines.

Incorrect adjustment of the control : the datum does notcorrespond to the collective pitch position. The rotor speedis affected. In twin-engine configuration, split of the twoN1 if the two data are different.





ENGINECONTROL LEVER

- Linkage broken or disconnected- Seizing- Incorrect adjustment

ANTICIPATORCONTROL

- Linkage broken- Incorrect adjustment

ENGINE CONTROL LEVER ANTICIPATOR CONTROL






Power turbine governor

Failure of the drive shaft : max N1 datum, the engineaccelerates to max N1 stop. In twin-engine configurations,the other engine decelerates to compensate.

Problem in the hydraulic system : wrong modulatedpressure, the required N1 is not obtained, possiblefluctuations.

Anticipator : see previous page.

Gas generator governor

Failure of the drive shaft : the engine acceleration tomaximun fuel flow and an overspeed is probable (extremelyremote as the shear section of the drive is on the fuel pumpshaft).

Compensating capsule anomaly : N1 will tend to varywith fuel temperature. The "sagging" of the capsule willreduce max N1.

Hydraulic system anomaly : instability, response timeout of tolerances.


P2 air supply pipe failure : the engine decelerates tominimum fuel flow. In twin-engine configuration, theother engine accelerates to compensate.

P2 air supply anomaly : any supply anomaly will affectthe acceleration time and therefore the response time.

A P2 supply problem to the deceleration control unit (forthe engines provided with this device) could cause flame-out in extreme transient conditions.

Fuel metering device

Any anomaly (eg : jamming of metering valve or constant∆P valve) results in an incorrect fuel flow control andtherefore instability.

Note : Remember that fuel flow can be controlled manuallywith the engine control lever.

Working piston

Any operation anomaly (a blockage) of the working pistoncauses starting difficulties : start impossible or slow,rapide start with overheat.






- Drive shaft failure- Compensating capsule anomaly- Hydraulic system anomaly

ACCELERATION CONTROL UNIT

- P2 air supply pipe failure- P2 air supply anomaly

METERING DEVICE

- Any anomaly

POWER TURBINE GOVERNOR

- Drive shaft failure- Hydraulic system anomaly

WORKING PISTON

- Operating anomaly





FAULT ANALYSIS - ENGINE INDICATING

Rotation speed indication

- Most problems lead to a complete loss of signal andtherefore no indication

- Check other parameters to confirm the failure of theindicating system (Refer to flight manual for operatinginstruction to be applied).

Gas temperature indication

Thermocouple anomaly : possible alteration of theindication ; the mean value of the remaining probes is read.

Broken wire of the pyrometric harness : loss of theindication.

Loose thermocouple probe : fluctuations or wrongindication.

Oil pressure indication

Min oil pressure switch : two possibilities :

- No indicating light

- Indicating light permanently "on".

Note : Check oil pressure and torque indication to confirmthe pressure switch anomaly.

Oil pressure transmitter : no indication at all or incorrectindication an case of failure.

Note : Check torque and min pressure light to confirm thefailure.

Torque indication

Hydraulic torquemeter : jamming or leak will cause anincorrect indication.

Note : The system does not operate in case of lubricatingpressure failure.

Torquemeter transmitter : no indication or incorrectindication in case of malfunction or incorrect adjustment.

Note : Pressure check to determine the failed componentof the system.





ROTATION SPEED INDICATION

- Anomaly of the speed sensor - indication


- Thermocouple anomaly- Broken wire of the pyrometric harness- Loose thermocouple probe

OIL PRESSURE INDICATION

- Min oil pressure switch anomaly- Oil pressure transmitter anomaly

TORQUE INDICATION

- Hydraulic torquemeter anomaly- Torquemeter transmitter anomaly





FAULT ANALYSIS - STARTING

Electrical power supply

A low DC supply voltage will cause difficult enginestarting and excessive gas temperature.

Note : The voltage should not decrease below 15 Voltsduring starting.

Starter

If the starter is failed :

- Insufficient torque during starting, slow accelerationwith high gas temperature

- No starting.

Ignition unit

A High Energy ignition unit failure causes no ignition at allor insufficient energy to obtain the correct pulse rate.

Note : Starting is nevertheless possible with one unitinoperative.

Igniter plug

In case of an igniter plug problem, no sparks are produced,or the sparks do not have enough energy to ignite the fuel.

Note : Starting is possible with one plug inoperative.

Starting control system

With a total power supply failure there is no voltage on theaccessories so no cranking and no ignition.

With no starter power supply there is no cranking ; but theignition operates (operation of the ignition system can beheard).

With no ignition power supply there is no ignition ; but thestarter operates.




FAULT ANALYSIS - STARTING

ELECTRICAL POWER SUPPLY

- Low DC supply voltage

STARTER

IGNITER PLUG

- Igniter anomaly

IGNITION UNIT

- HE ignition unit anomaly

STARTING CONTROL SYSTEM

- Total power supply loss- Starter power supply loss- Ignition power supply loss

- Starter motor anomaly





FAULT ANALYSIS - ELECTRICAL SYSTEM (1)

Electrical power supply

- DC power supply anomaly during start : no startingor starting "difficulties" (sluggish start, high gastemperature)

- DC power supply anomaly in "normal operation" :• Total failure : the engine remains in operation but

without some indicating and without overspeed safety.• Battery failure : back-up by DC generator• Generator failure : back-up by battery or other

source.

- Internal supply anomaly of the tachometer box : aninternal supply anomaly will cause the non operation ofthe system (the light remains illuminated).

Start control system

Refer to fault analysis of starting.

Indicating systems

Refer to fault analysis of indicating systems.





ELECTRICAL POWER SUPPLY START CONTROL SYSTEM INDICATING SYSTEMS

- Anomaly of DC supply :• during start• in normal operation

- Internal supply anomaly of the tachometer box

- Refer to fault analysis of starting - Refer to indicating systems






Overspeed pick-up

One pick-up : fault indicated by the light (remaining "on"above 25 % N2).

Overspeed electro-valve

Electro-valve failure : no engine shut-down in case ofoverspeed; dormant fault which would be detected duringthe periodic test.

Valve jammed open : no start (remote probability).

Tachometer box

Inoperative : no overspeed system capability but theproblem is indicated by the test.

Unwarranted operation : extremely remote probabilityconsidering the design of the system.

Super Contingency Power system

Abnormal operation of the control system : no armingof super contingency rating.

Abnormal operation of SCP box : no indicating of"SCP" or recording of life not correct.





OVERSPEED PICK-UP

- One pick-up


- Electro-valve failure- Valve jammed "open"

SCP SYSTEM

- Arming circuit inoperative- SCP box

TACHOMETER BOX

- Inoperative- Unwarranted operation

TEST

OSCILLATOR

N2

N2

120 %

120 %

VS

ENGINE

SHUT-DOWN

S'




25 %

25 %

REARMING





FAULT ANALYSIS - ENGINE INSTALLATION

Engine compartment

Lack of ventilation can cause an increase of temperaturewhich can be, in extreme cases, detected by the firedetection system.

Engine attachment

Incorrect adjustment, abnormal clearance or misalignmentwill cause vibration or abnormal stresses with all the usualconsequences.

Air intake and gas exhaust

A partial obstruction affects the engine performance.

Particular instructions are given in the maintenance manual,for engine operation in a "hostile atmosphere" :

- Sand : increases erosion

- Salt : causes corrosion

- Pollution : both erosion and corrosion.

Drains and air vents

In case of obstruction of a drain, effect according to thedrain system (refer to system concerned).

Particular attention to obstruction hazard caused bydeformation during engine removal and installation orcaused by insects in some countries.

Power transmission

A failure of the power shaft causes a power turbineoverspeed and automatic engine shut-down by theoverspeed protection system (twin-engine only).

Misalignment of the shaft causes vibration and possiblefailure.

Fire protection

The engine fire protection system is described in theaircraft manual.

Air tappings

Any air tapping affects the engine performance. Anexcessive air tapping reduces the power available ; orincreases the gas temperature for a given power rating.




FAULT ANALYSIS - ENGINE INSTALLATION

AIR INTAKE ANDGAS EXHAUST

- Partial obstruction- Dirty atmosphere

ENGINE COMPARTMENT

- Lack of ventilation

ENGINE ATTACHMENT

- Incorrect adjustment- Abnormal clearance- Misalignment

POWER TRANSMISSION

- Shaft failure- Misalignment

DRAINS AND AIR VENTS

- Obstruction

AIR TAPPING

- Excessive air tapping

FIRE PROTECTION

- Refer to aircraft documentation- Detector anomaly





TROUBLE SHOOTING

General

Trouble shooting is a very important aspect of maintenance.

An "efficient" diagnosis reduces the extra maintenancecosts due to unjustified removals and additional diagnosistime.

In fact, even with a very high reliability product, failure isinevitable and required actions should be taken efficiently.

After the fault analysis which consists of finding the effectof a given failure, this section considers the case inreverse ; i.e. : finding the probable cause of a fault.

Repair procedure

The corrective maintenance actions should be guided bytwo main considerations :

- Minimum downtime

- Justified removal of components.

The procedure to be applied depends on the case but ingeneral, a good knowledge of the product and a methodicalresearch would permit a safe diagnosis and a quickcorrective action.

Generally, the procedure includes failure identification,its analysis, the isolation of the component, and the repairchoice.




TROUBLE SHOOTING

Or otherperception

Symptoms (and other additional indications…)All factors should be taken into considerationas well as the interactions.

Analysis of the fault

Identification of the faulty component

Additionalchecks

Deduction Substitution

Remedy(adjustment, replacement, cleaning, repair...)

Fault(single, double,

dormant)

Inevitable Random

Trouble shooting

- Diagnosis- Remedy- Repair- Check

- Adequate means and procedures- Training of personnel

MTTR(Mean Time To Repair)

Total time requiredfor repairing





TROUBLE SHOOTING - STARTING FAULTS (1)

No effect after selecting startN doesn't increase

Is ventilationpossible ?

- Overspeed not rearmed- Starting circuit (circuit breaker, selector switch, relay …)

- Starter contactor- Electrical supply- Starter

Yes No

Note : Further tests (engaging noise of the contactor...) help locate the failure.





The ignitionsystem operates

(noise of HE components)

- Start electro-valve- Injectors

- HE ignition units- Igniter plugs

Yes No

Note : Refer to the testprocedure fordiscrimination

Start is possiblewith one injector and one

igniter plug providedthey are on the same side

Note : It is also possible tocheck for a fuel flowthrough the combustionchamber drain.

Or fuel supply problem

Fuel flows

Ignition system - Start electro-valve- Fuel supply

Yes No

On selection of start, N increases, but no t4






Abnormal t4

t4 ≈ 200°

Variant : N and t4 increase, but the starting is not effective, so no N2

t4 > 200°but insufficient

t4 too high

Increase due to theinjectors, but themain fuel system isnot supplied

- FCU- Control lever- Procedures

- Overspeed drain valve- FCU- Control lever- Inadequate fuel supply (LP system, filters...)

- Pressurising valve- Overspeed and drain valve

Note : In all cases, check the electricalsupply (battery voltage)

Failure of the accessory drive shaft




TROUBLE SHOOTING - FAULTS DURING SHUT-DOWN

Shut-down selected by movingthe throttle lever rearwards

N1deceleration

Control leverdisconnected

Yes

Stop selection

The engine stopsN1 , t4

No

Yes

Poor sealing ofthe fuel system

No

Abnormal friction of the rotating assembly

The engine shut-down can then beaffected by the manual controlsystem or by the fuel shut-off (fire)valve.Further checks required.

No

Normalshut-down

YesCorrect

rundown time





TROUBLE SHOOTING - FAULT DURING VENTILATION

Ventilation selection(press and hold)

N1 indication

Yes

The gas generatoris driven

No

Accessory drive train"Normal"

ventilation

Note : 15 sec. max to avoid starter overheat

NoYes

The starter turns

NoYes

N1 indicationStarting ispossible

NoYes

- Starter contactor- Starter- Electrical supply

Ventilationselector




TROUBLE SHOOTING - LUBRICATION FAULTS (1)

Abnormal oil pressure indication

FluctuationNo pressureLow High

- Oil condition- Sealing- Internal blockage- Pressure relief valve

- Filter blockage- Pressure relief valve

- Measuring system- Blockage of a jet

Min oil pressurelight illuminated

Yes No

- Failure of the pump shaft- Pressure relief valve- Internal blockage- Large internal or external leak

Pressure indicating system :- Transmitter- Indicator- Harness





TROUBLE SHOOTING - LUBRICATION FAULTS (2)

Abnormal oil temperature indication

HighLow

Yes No

- Measuring system- Insufficient cooling- Local lubrication problem (blockage of a jet)

Measuring system

Abnormal oil consumption

Visible leak

External leak Internal leak

Pipe oraccessory

Contamination of thebleed air Leak from the coldsection labyrinth seals(front section)

Smoke and oil in the exhaust pipeLeak from the hot sectionlabyrinth seals.(rear section)

General vent pipefailure (blockage,wrong indication)

P2 air pipe failure

Oil contamination

Corrective actionDetection

According to amount, originand rate of contamination...

- Magnetic plugs- Analysis- Color, aspect




TROUBLE SHOOTING - FAULTS LEADING TO ENGINESHUT-DOWN IN FLIGHT

Uncommanded engine shut-down

Yes

Actual overspeed

No

- Loss of signal- Tachometer boxNote : Unlikely

NoYes

Engine internalanomaly

N2, N1, Tq, t4, oil pressure

Operation of thepower turbine overspeed

system

Abnormal fuelsupply :- Pump shaft failure- Pipe failure- Water in fuel- FCU

Water or iceingestion

- Failure of the power transmission shaft- FCU

Doubt

Rearming andcorrective actions

Note : In a twin-engine configuration, the engine which remains in operation supplies the required power within its limits.





TROUBLE SHOOTING - MISCELLANEOUS CASES (1)

Bleed valve(closed)

FCUacceleration controller

Abnormal gas temperature indication

Yes

Max N1 reached

No

Dirtycompressor Engine internal problemMeasuring system

Compressor surge

Engine anomaly (air intake,compressor...)

Loss of power

- Blockage of the injection system- Isufficient fuel supply (pumps, filters...)- FCU - temperature compensation device- Anticipator, adjusment

- Torque and gas temperature indication- Engine : dirty compressor, turbine creep,etc ...

Note : Particular attention : check of the max N1.





Gas generator rotation speed N1

Incorrectresponse time

- FCU- Anticipator- Gas generator internal problem

Overspeed

FCU

FCU

FluctuationUncommandeddeceleration

Uncommandedacceleration

- Abnormal fuel supply- FCU- Abnormal operation of one of the fuel system accessories (refer to the chapter "fuel system")- Loss of P2 supply to FCU

- Air in the fuel system- Dirt in the fuel system- Constant ∆P valve- Blockage of the centrifugal wheel- FCU






Power turbine rotation speed N2

Overspeed

- Failure of the transmission shaft- Control system failure

Incorrect speed

- Indicator- FCU- Anticipator adjustment

Vibration

Gas generatoror power turbine

rotating assembly

Engine attachmentPower transmissionshaft

Engine - aircraftalignment





Instruments

Note : Failures which cause abnormal indication.

- Inaccurate indication (transmitter / receiver)- Systems associated with the engine

Refer to other cases

Fire "failure"Unjustified illumination Refer to aircraft documentation

No illumination in test mode Refer to aircraft documentation

Fire warningUnjustified illumination Detector failure

No illumination in test mode Test system

Lights

Justified illumination

No illumination in the event of overheat

Overheat or fire

Detection circuit

Chip detection Unjustified illumination Sensor "sensibility"

No illumination despite particles Electrical magnetic plug orwiring failure

Justified illumination Deposit of particles

Low oil pressure

Oil filter pre-blockageFuel filter pre-blockage(according to version)

Unjustified illumination Pressure switch

No illumination despite effective pressure drop Pressure switch

Justified illumination Pressure drop

Unjustified indication Indicator

No indication despite thedifferencial pressure increase

Indicator

Justified indication Blockage





TROUBLE SHOOTING - CONCLUSION

Despite the high reliability of the product failures remaininevitable and happen at random. But their rate and effectscan be reduced if the "enemies" of the engine are taken intoconsideration.

When the failure occurs, you have to be in a position tocorrect it.

"Enemies" of the engine

The traditional adverse conditions for this type of engineare :

- Supply (air, oil, fuel, electricity)

- Operation ("non respect" of instructions and procedures)

- Maintenance ("non respect" of inspection frequenciesand of the strict application of the procedures).




TROUBLE SHOOTING - CONCLUSION

MAINTENANCE

- "Non respect" of inspection frequencies- Various mistakes- Wrong logistics.

OPERATION

- "Non respect" of instructions and procedures- Severe operating conditions.

AIR

- Sand- Salt- Miscellaneous pollution.

OIL

- Not in conformity with specifications- Miscellaneous contamination.

FUEL

- Not in conformity with specifications- Water in fuel- Sulphur + salt in the air = sulfidation.

ELECTRICITY

- Too low voltage during starting- Interference.



For training purposes only© Copyright - TURBOMECA - 2000 CHECKING OF KNOWLEDGE

16-CHECKING OF KNOWLEDGE

- Introduction .................................................................. 16.2

- Questionnaire 1 ............................................................. 16.3

- Questionnaire 2 ............................................................. 16.6

- Questionnaire 3 ............................................................. 16.12

- Questionnaire 4 .............................................................. 16.15 to 16.30




CHECKING OF KNOWLEDGE

INTRODUCTION

Method

Continuous checking helps to ensure the information isassimilated. It is more a method of work than a testing inthe traditional sense.

Objectives of the questionnaires

The questionnaires permit a progressive assimilation andlong term retention. The questionnaires are a subject fordiscussion (effects of group dynamics). They also permitstudents to consider important subjects several times un-der different aspects.

Integration into the training programme

- First hour every day for revision of the subjects previ-ously studied

- After each chapter (or module) of the course

- At the end of the training course.

Types of questionnaires

Several types of questionnaire can be employed during acourse :

- Traditional written questionnaire

- "Short answer" questionnaire

- Multi Choice Questionnaire (MCQ)

- Oral questionnaire

- Learning Through Teaching (LTT ; the student has toexplain a given subject).

Examination

The final examination at the end of the course consists ofthree tests : written, oral and practical. A certificate and anapproval card are given to the student if the results aresatisfactory.




QUESTIONNAIRE 1

This traditional questionnaire is established according tothe same plan as the training manual in which the answerscan be found.

Power plant1 - List the main functional components of the power

plant.

2 - Explain the thermodynamic operation of the engine.

3 - State the following features (at take-off, in standardatmosphere) :

• Power on the shaft

• Output shaft rotation speed

• Mass of the engine with specific equipment

• Main overall dimensions of the power plant

4 - Explain the principle of engine adaptation to helicopterpower requirements.

5 - Give a definition of the operating ratings.

6 - How do temperature and altitude affect the engineperformance.

Engine1 - List the main components of the gas generator.

2 - State the following characteristics :

• Compression ratio

• Turbine entry temperature

• N2 speed at 100 %

• N1 speed at 100 %

3 - Describe the power turbine assembly.

4 - Describe the fuel injection system.

5 - List the engine driven accessories.

6 - List the bearings which support the gas generator.

7 - Describe the system used for bearing sealing.

8 - Describe the modular construction of the engine.

9 - Describe the engine air intake.

10 - List the manufacturing materials of the engine maincomponents.





QUESTIONNAIRE 1 (continued)

Oil system1 - Draw a simplified diagram of the oil system.

2 - Explain the general operation of the oil system.

3 - Describe the oil filter assembly.

4 - State the location of strainers and magnetic plugs.

Air system1 - List the functions ensured by the internal air system

(secondary system).

2 - List the function of the various air tappings.

3 - Why are the start injectors ventilated ?

4 - Explain the purpose and the operation of the compressorbleed valve.

Fuel system1 - What is the purpose of the Booster pump.

2 - Describe the fuel pump.

3 - Describe the fuel metering unit.

4 - What is the purpose of the constant ∆P valve.

5 - Explain the principle of fuel injection (main and startinginjection).

6 - Explain the operation of the overspeed & drain valve.

Control system1 - List the main functions of the control system.

2 - Explain the basic principle of the control system.

3 - Explain the operating principle of the speed control.

4 - Describe the purpose and operation of the anticipatorcontrol.

5 - Explain the operation of the acceleration controller.

6 - What are the main sections of the FCU.

7 - Describe and explain the operation of the power turbineoverspeed system.

8 - Describe the principle of load sharing in a twin engineconfiguration.

Indicating system and manual control1 - Describe the manual control system.

2 - Describe the power turbine speed indicating system.

3 - Explain the operating principle of the torquemetersystem.

4 - Describe the gas temperature indicating system.





Starting1 - Describe the cranking function of the engine.

2 - Describe the ignition system (ignition unit and igniterplugs).

3 - List the main phases of the starting cycle.

4 - Describe the starting control electrical system.

Electrical system1 - List the engine electrical accessories.

2 - List the sensors (state the type of signal produced).

3 - Describe the electrical harnesses and connectors.

Engine installation1 - Describe the attachment of the engine to the aircraft.

2 - Describe the engine power drive and the powertransmission.

3 - List the various engine / aircraft interfaces.

4 - Describe the fire protection system of the engine.

Limitations and engine handling1 - List the main operating limitations of N1.

2 - Describe the engine starting procedure.

Various aspects of maintenance1 - List the main practices of a periodic inspection.

2 - List the methods used for "on condition monitoring".

3 - List the technical publications used for enginemaintenance.

Maintenance procedures1 - Describe the compressor cleaning procedure.

2 - Name the LRUs of the air system.

3 - Explain the attachment of each of the modules.

Fault analysis and trouble shooting1 - Carry out the fault analysis exercises.

2 - Carry out the trouble shooting exercises.





Questions Answers

1 - ARRIEL 1 power class ?

2 - Power turbine rotation speed at100 % ?

3 - Type of main fuel injection ?

4 - Number of engine modules ?

5 - Number of power turbine stages ?

6 - Meaning of AEO ?

7 - Mass of the equipped engine ?

8 - Power evolution when altitudeincreases ?

9 - Specific fuel consumption at350 kW ?

10 - Flight envelope - Max altitude ?

11 - Flight envelope -Max temperature ?

12 - Start envelope - Max altitude ?

13 - Engine air flow at 100 % N1 ?

14 - Overall compression ratio ?

15 - Max turbine entry temperature ?

16 - Gas generator rotation speed at100 % N1 ?

17 - Direction of rotation of the gasgenerator ?

18 - Direction of rotation of the powerturbine ?

19 - Manufacturing material for theaxial compressor ?

20 - What type of bearing is the axialcompressor bearing ?

QUESTIONNAIRE 2

The following questions require short and accurate an-swers.

The student can answer orally or in the space provided forthe answers.

Questions Answers




30 - Type of power turbine frontbearing ?

31 - Type of gas generator rear bearing ?

32 - To which module does the powerturbine nozzle guide vane belong ?

33 - Type of power turbine ?

34 - Does the exhaust pipe belong to onemodule (yes or no) ?

35 - Type of exhaust pipe attachment ?

36 - Number of gears in the reductiongearbox ?

37 - Rotation speed of the intermediategear of the reduction gearbox ?

38 - Number of driven accessories onthe accessory gearbox ?

39 - Manufacturing material for theaccessory gearbox casing ?

21 - How is the axial compressormounted on the gas generatormodule ?

22 - Axial compressor compressionratio ?

23 - Manufacturing material for thecentrifugal compressor wheel ?

24 - Number of stages of the centrifugalcompressor diffuser ?

25 - Type of combustion chamber ?

26 - Manufacturing material for thecombustion chamber ?

27 - Type of main fuel injection ?

28 - Pressure drop in the combustionchamber ?

29 - Number of stages of the gasgenerator turbine ?


Questions Answers Questions Answers





50 - Setting of the low oil pressureswitch ?

51 - Max oil temperature ?

52 - Location of the centrifugal breather ?

53 - Air tapping for the pressurisation ofthe power turbine front bearing ?

54 - Air pressure at the centrifugalcompressor outlet ?

55 - Temperature at the centrifugalcompressor outlet ?

56 - When does the start injectorventilation begin ?

57 - Max air tapping flow ?

58 - Type of compressor bleed valve ?

59 - Position of the bleed valve duringstarting ?

40 - Is the oil pressure adjustable ?

41 - Number of pumps in the oil pumppack ?

42 - Type of oil pumps ?

43 - What is the setting of the checkvalve at the pressure pump outlet ?

44 - Filtering ability of the oil filter?

45 - Setting of the oil filter by-passvalve?

46 - Which bearings are ball bearings ?

47 - Type of seal for the gas generatorrear bearing sealing ?

48 - Max oil consumption ?

49 - Type of oil pressure transmitter ?






60 - What are the bleed valve controlsignals ?

61 - Where is the bleed valve fitted ?

62 - Type of fuel filter ?

63 - Filtering ability of the fuel filter ?

64 - Setting of the fuel filter by-passvalve ?

65 - Type of fuel pump ?

66 - Position of the pump pressure reliefvalve in normal engine running ?

67 - Type of fuel metering device ?

68 - Position of the constant ∆P valvewhen the engine is stopped ?

69 - Type of manual fuel flow control ?

70 - Type of valve for injectorventilation ?



71 - How is the anticipator signaltransmitted ?

72 - Setting of the fuel pressurisingvalve?

73 - Fuel flow through the startinjectors?

74 - Number of start injectors ?

75 - Position of the combustion chamberdrain valve when the engine isstopped ?

76 - Type of fuel control system ?

77 - Signals for the accelerationcontroller

78 - Average response time of thecontrol system

79 - Is the static droop compensated

80 - Position of the main valve withlever in emergency plus





91 - Where is the oil pressure transmitterlocated ?

92 - How are the thermocouplesconnected (parallel or series) ?

93 - Location of the torquemeter ?

94 - Type of torque sensor ?

95 - Type of signal output by the torquesensor ?

96 - Is the torque transmitter associatedwith a particular module ?

97 - Type of starter ?

98 - Type of ignition system ?

99 - Gas generator rotation speed atstarter cut-off ?

81 - Meaning of OEI ?

82 - Type of N2 controller ?

83 - Position of the auxiliary valve withthe lever in the emergency minusrange ?

84 - Closing threshold of the reinjectionprohibition switch

85 - What keeps the metering needleclosed when the control lever isclosed ?

86 - Position of the manual control leverin normal engine running ?

87 - Type of speed sensors ?

88 - What is the average torque pressureat 100 % torque ?

89 - How does the low oil pressureswitch sense the pressure ?

90 - Number of thermocouple probes ?






111 - Max gas temperature duringstarting ?

112 - Low oil pressure switch setting ?

113 - Max oil temperature ?

114 - Min electrical supply voltagebefore starting ?

115 - Type of recommended lubricant ?

116 - Meaning of IPC ?

117 - Meaning of TBO ?

118 - Is borescopic inspection of thecombustion chamber possible ?

119 - Procedure in case of operation insuper contingency rating ?

120 - Is there an adjustment of thetorquemeter ?

100 - Number of igniter plugs ?

101 - Max duration of a ventilation ?

102 - Is the ignition cable integral withthe igniter plug ?

103 - Number of electrical connectors ?

104 - Location of the tachometer box ?

105 - Type of seal on the power shaft ?

106 - Type of connection engine/MGB ?

107 - Number of engine drains ?

108 - Engine operating envelope ; minand max altitude pressure?

109 - Max starting altitude ?

110 - Power turbine max overspeed ?







QUESTIONNAIRE 3

This multi-choice questionnaire is used to review, in arelatively short time, certain important points and to testthe acquired knowledge.

Answers to the questions can be found at the end of thequestionnaire.

1 - The ARRIEL 1 engine is :a) a free turbine turboshaft engineb) a turbo-jet enginec) a fixed turbine turboshaft engine.

2 - Section of passage of the compressor diffusers :a) regularb) divergentc) convergent.

3 - Type of combustion chamber :a) annular with centrifugal injectionb) annular, reverse flowc) annular, indirect flow.

4 - The power turbine nozzle guide vane belongs to :a) module M04b) module M03c) module M02.

5 - Type of exhaust pipe attachment :a) boltsb) mounting padsc) clamp.

6 - How many bearings support the gas generator :a) 4b) 2c) 3.

7 - The engine includes :a) a hot section and a cold sectionb) 5 modulesc) 4 modules.

8 - Type of oil system :a) dry sumpb) constant pressurec) lubrication by splashing.

9 - Setting of the oil filter pre-blockage indicator :a) lower than the by-pass valveb) higher than the by-pass valvec) the same as the pump valve.

10 - The oil strainers are located :a) at the outlet of the pumpsb) on the inlet of the scavenge pumpsc) at the inlet of the lubricated components.

11 - Is there a max oil temperature :a) yes, 60 °Cb) noc) yes, 115 °C maxi.





12 - The air tapped at the centrifugal wheel outletpressurises :a) some labyrinth sealsb) the tankc) the pumps.

13 - Position of the bleed valve during flight ?a) openb) closedc) depends on conditions.

14 - Ventilation of start injectors :a) does not existb) is made with air from the compressorc) is made with atmospheric pressure air.

15 - The injection centrifugal wheel is drained :a) permanentlyb) to enable the ventilation cyclec) during engine shut-down.

16 - The max speed of the gas generator is :a) limited by a hydraulic stopb) limited by a mechanical stopc) not limited by the Fuel Control Unit.

17 - The gap between the metering needle & the fork :a) represents the instant flow stepb) varies with N1c) provides a smoother acceleration.

18 - The fuel pump is :a) vane typeb) gear typec) centrifugal.

19 - The fuel system pressurising valve :a) is electrically controlledb) operates when overpressure occursc) gives priority to the start injectors.

20 - The starter is de-energised :a) automaticallyb) by air pressurec) manually.

21 - The thermocouples are wired :a) in seriesb) in parallelc) on the turbine casing.






22 - The torque indicating system :a) is hydraulicb) is not usedc) is of phase displacement type.

23 - Number of thermocouple probes :a) 3b) 4c) 5.

24 - Max oil pressure ?a) 3 barsb) 6 barsc) 8 bars.

25 - Bleed valve position is transmitted by :a) a pressure switchb) a micro switchc) an RVDT.

26 - The starter is supplied via a :a) relayb) micro switchc) transistor.

27 - Starting is possible with one igniter :a) yesb) noc) yes, in emergency.

28 - HE ignition means :a) Hot Electrodeb) High Energyc) High Emission.

29 - Borescopic inspection is used to check :a) the external parts conditionb) the condition of internal parts which are not

accessible without removalc) the reduction gearbox condition.

30 - The reliability of the engine is :a) goodb) fairly goodc) extremely good.

1 - a6 - c

11 - c16 - b21 - b26 - a

Answers

2 - b7 - b

12 - a17 - a22 - a27 - a

3 - a8 - a

13 - c18 - b23 - a28 - b

4 - b9 - a

14 - b19 - c24 - c29 - b

5 - a10 - b15 - c20 - c25 - b30 - abc ?




2 - Name the reference stations :

0 - ................................. 3 - ..................................

1 - ................................. 4 - ..................................

2 - ................................. 5 - ..................................

Max take-off power ........................

Compression ratio .......................

Engine air flow .......................

N2 speed at 100 % ......................

N1 speed at 100 % .......................

QUESTIONNAIRE 4

This questionnaire is a sort of drill which is also used to testand perfect the knowledge acquired.

1 - Complete this table (with values) :

G

Q

C T 1 T 2

CC

10 2 3 4 5






3 - Engine description - Complete the legend of thediagram :

1 - ................................................... 2 - ...................................................... 3 - .................................................

4 - ................................................... 5 - ...................................................... 6 - ................................................

7 - ................................................... 8 - ...................................................... 9 - ................................................

1

7

2 3 4 5

68

9





4 - Oil system - Complete the legend of the diagram :

1 - ................................................... 2 - ...................................................... 3 - .................................................

4 - ................................................... 5 - ...................................................... 6 - ................................................

ENGINEAIRFRAME

1 2

6

3

4 5






5 - Complete the following table :

Injector ventilation


Bleed valve control pressure

Injection wheel pressurisation

Axial compressor bearing pressurisation

Gas generator rear bearing cooling

Power turbine bearing chamber labyrinth pressurisation

Gas generator turbine disc cooling

P0 P1' P2





6 - Complete the legend of the compressor field diagram :

A - ................................................... B - ...................................................... C - .................................................

A

B

C

COMPRESSIONRATIO P2 / P0

AIR FLOW G






7 - Fuel system - Complete the legend :

1 - ................................................... 2 - ...................................................... 3 - .................................................

4 - ................................................... 5 - ...................................................... 6 - ................................................

7 - ................................................... 8 - ...................................................... 9 - ................................................

10 - ................................................... 11 - ...................................................... 12 - ................................................

1 2 3 4 5 6

7

8

9

101112





8 - Control system - List the components :

1 - ................................................... 2 - ...................................................... 3 - .................................................

4 - ................................................... 5 - ...................................................... 6 - ................................................

7 - ................................................... 8 - ......................................................

1

2 3

P2

Q

+

+

+

N1*

4

N2

N2*

N1

5

6

8

7







Fuel pump ..........................................................

Pump pressure relief valve ................................

Constant ∆P valve ..............................................

Metering needle .................................................

Start injector electro-valve.................................

Overspeed electro-valve ....................................

Pressurising valve ..............................................

Main valve .........................................................

Combustion chamber drain valve ......................

Engine stopped Engine in stabilisedflight





10 - Complete the following graphs during a load C increase :

Power turbinespeed N2

Fuel flowQ

Gas generatorspeed N1

time

time

time

time

Load C





QUESTIONNAIRE 4 (suite)

11 - Fuel system - List the components :

1 - .......................... 2 - .......................... 3 - ......................... 4 - ..........................

5 - .......................... 6 - .......................... 7 - ......................... 8 - ..........................

9 - .......................... 10 - .......................... 11 - ......................... 12 - ..........................

13 - .......................... 14 - .......................... 15 - ......................... 16 - ..........................

17 - .......................... 18 - .......................... 19 - ......................... 20 - ..........................

21 - .......................... 22 - .......................... 23 - ......................... 24 - ..........................

11

12

13

14

15

16

17

18

19

21 22 20 23 24

1

2

3

4

6

5

7

9

8

10





12 - Drain system - List the drains :

1 - .......................... 2 - .......................... 3 - ......................... 4 - ..........................

5 - .......................... 6 - .......................... 7 - ......................... 8 - ..........................

4 3

5

6 7

8

1 2







14 - List the main resources for on condition monitoring :

1 - ..............................................................................................................

2 - ..............................................................................................................

3 - ..............................................................................................................

4 - ..............................................................................................................

5 - ..............................................................................................................

6 - ..............................................................................................................

7 - ..............................................................................................................

8 - ..............................................................................................................

Number of lifting points ?

Type of fire detectors ?

Number of drain points ?

Air used for intake anti-icing ?

Max air tapping flow for aircraft use ?

Loss of power due to aircraft tapping ?





15 - Define of the following documents :

Maintenance manual

Spare parts catalogue

Tool catalogue

Service bulletin

Service letter

Engine log book

Flight manual






16 - Maintenance procedures

1 - List 2 advisory notices of "warning"category.

2 - Time of non operation requiringlong term storage.

3 - Compressor washing - Product andprocedure.

4 - Procedure to rotate the powerturbine for borescopic inspection.

5 - Location of the vibration sensorInstallation.

6 - Type of attachment of thecompressor bleed valve.

7 - Type of attachment of the fuelcontrol unit.




1 - Dirty compressor.

2 - Fracture of the power shaft.

3 - Fracture of the accessory drive shaft.

4 - Obstruction of the power turbinepressurisation pipe.

5 - Blockage of the fuel filter element.

6 - Partial clogging of the centrifugal fuelinjection wheel.

7 - Jamming of the constant ∆P valve.

8 - No electrical supply of the startinjector valve.

9 - Fracture of the P2 pipe to the FCU.

10 - Fuel leak from the start purge valve.


17 - Fault analysis. Indicate (briefly) the effects of the following faults.






18 - Trouble shooting. Indicate the probable cause(s) of the following faults.

1 - On start selection, N increases butnot the gas temperature.

2 - On start selection, N and t4 increasebut not sufficiently to obtain start.

3 - Surge of the compressor.

4 - Max power not obtained.

5 - On stop selection, the engine doesnot completely shut-down.

6 - Incorrect speed of the helicopterrotor.

7 - Power turbine overspeed.

8 - Drop of oil pressure.

9 - Abnormal t4 temperature.

10 - N1 overspeed.

END

but not the END of your t ra iningwhich must be cont inued,

harmonizing knowledge and experience.

THANK YOU for your kind at tent ion.

of this manual and (maybe also) of the course

Au revo i rGood bye

Ad iósAuf Wiedersehen

AdeusAr r i vederc i

Fa rve lTo t z i ens

A d j öNäkemi in

A n t i oMa sa laam

TURBOMECA Training Centre

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Name ....................................................................................................................................... .

Address .................................................................................................................................... .

Course .............................................................. from............................ to ............................. .

REMARKS

Remarks (appreciations, criticisms, suggestions...) should be forwarded to :

TURBOMECACENTRE D'INSTRUCTION40220 TARNOS - FRANCE

4 0 2 2 0 T A R N O S - F R A N C EC E N T R E D ' I N S T R U C T I O N

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