Aps 3200 Training

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HSPS CT/ NOV. 2006 © 2006 Hamilton Sundstrand Corporation

APS 3200 AUXILIARY POWER UNIT

TRAINING COURSE

(ECB SOFTWARE VERSION 6.0)

LINE MAINTENANCE AND FAULT ISOLATION

THIS HANDBOOK IS FOR REFERENCE PURPOSES ONLY.IF FAULT ISOLATION OR MAINTENANCE IS REQUIRED, REFERTO THE APPLICABLE MANUFACTURERS TECHNICAL MANUAL

FOR SPECIFIC PROCEDURES

Hamilton Sundstrand reserves the right to make changes in specificationsand other information contained in this publication without prior notice

NOTICE

THIS TRAINING MANUAL IS TO BE USED FOR TRAINING PUPOSES ONLY

This training manual was prepared by Hamilton Sundstrand for training purposes only.

Some information contained herein is proprietary and/or copyrighted information of Hamilton Sundstrand. As a condition of, and as consideration for receiving thisdocument, the recipient agrees that this document and the information containedtherein shall not be disclosed outside the recipient or duplicated or used for anypurpose without Hamilton Sundstrand’s prior written consent.



HSPS CT/NOV. 2006

HAMILTON SUNDSTRAND PROPRIETARY

Use or disclosure of this data is subject to therestriction on the title page of this document



HSPS CT/NOV. 2006HAMILTON SUNDSTRAND PROPRIETARY

AIRBUS AIRCRAFT

Use or disclosure of this data is subject to theRestriction on the title page of this document



HSPS CT/NOV. 2006HAMILTON SUNDSTRAND PROPRIETARY





HSPS CT/NOV. 2006 Page i


APS 3200 Auxi liary Power Unit

Front Matter

Use or disclosure of this data is subject to therestriction on the title page of this document.



HSPS CT/NOV. 2006 Page ii



TABLE OF CONTENTS

SUBJECT PAGE

Preface............................................................................................iii

Abbreviations ................................................................................. v

APU Leading Particulars ...............................................................viii

SUBJECT SECTION

Introduction...................................................................................... 1

Power Unit.......................................................................................2

Oil System....................................................................................... 3

Fuel System ....................................................................................4

Air System....................................................................................... 5

Control System................................................................................ 6

Indicating System............................................................................ 7

Starting System............................................................................... 8

Electrical System.............................................................................9

APU Installation.............................................................................10

Maintenance.................................................................................. 11

Fault Isolation................................................................................12

Troubleshooting............................................................................. 13



HSPS CT/ NOV. 2006 Page iii



PREFACE

GENERAL DESCRIPTION

The APS 3200 Auxiliary Power Unit Maintenance Training Course,developed by the Customer Service Training Group of HamiltonSundstrand Power Systems, is designed to give the student anunderstanding of the various components of the Auxiliary Power Unit(APU) and their functions. This course also provides routinemaintenance and troubleshooting.

STUDENT WORKBOOK

This workbook is intended for the “limited” purpose of providingcomponent familiarization, general data, and support information for

this maintenance course.

This is an uncontrolled document and will not be updated or revisedon a regular basis. Specific values given in this document such asspeed, temperature, and pressure are provided for the purpose ofillustration and are not necessarily representative of the true valuesof the APS 3200 APU.

FAA AND AIRCRAFT MANUFACTURER APPROVEDPUBLICATIONS

The Airline is provided a variety of FAA and Aircraft Manufacturerapproved publications for the APS 3200 APU. These publicationsare:

Aircraft Flight Crew Manuals

Aircraft Maintenance Manuals

Engine and Component Maintenance Manuals

Service Bulletins

Chapter 49 of the aircraft maintenance manual presents detailed APU and LRU removal and installation procedures plus maintenanceand servicing techniques that can be accomplished at the flight-line.Careful study of Chapter 49 will add to the student's expertise introubleshooting and maintaining the Hamilton Sundstrand APS 3200

APU.



AIRCRAFT APPLICATIONS

The information presented in this course applies to the followingaircraft:

AIRBUS 318, 319, 320, 321

HSPS CT/NOV. 2006 Page iv





HSPS CT/NOV. 2006 Page v



LIST OF ABBREVIATIONS

The abbreviations/symbols shown below are used in this manual:

A/D Analog/Digital

A/C Aircraft AC Alternating Current

ACARS Aircraft Communication Addressing and Reporting System

ACMS Aircraft Condition Monitoring System

ADIRU Air Data Inertial Reference Unit

AIDS Aircraft Integrated Data System

APIC Auxiliary Power International Corp.

APS Auxiliary Power System APU Auxiliary Power Unit

ARINC Aeronautical Radio Inc.

ATA Air Transport Association

AVAIL APU Available

BATT Battery

BCV Bleed Control Valve

BITE Built-In Test EquipmentBMC Bleed Monitor Computer

CB Circuit Breaker

cc/h Cubic centimeters per hour

CFDS Centralized Fault Display System

CLR Clear

CMM Components Maintenance ManualCPU Central Processor Unit

D/A Digital/Analog

DC Direct Current

ECAM Electronic Centralized Aircraft Monitoring

EC dB Decibel

B Electronic Control Box

ECS Environmental Control System

EGT Exhaust Gas TemperatureEMI Electro-Magnetic Interference

EPLD Erasable Programmable Logic Device

ETOPS Extended Twin Engine Operations

FADEC Full Authority Digital Electronic Controller

FAR Federal Airworthiness Regulation

FCU Fuel Control Unit

FET Field Effect TransistorFOD Foreign Object Damage

ft Feet

FWD Forward

GBX Gearbox



HSPS CT/NOV. 2006 Page vi




GCU Generator Control Unit

GMT Greenwich Mean Time

GPH Gallons Per Hour

HOT High Oil TemperatureHP Horse PowerHSPS Hamilton Sundstrand Power System

Hz Hertz

ICAO International Civil Aviation Organization

ID Identification

IGV Inlet Guide Vane

IPC Illustrated Parts Catalogue

ISA International Standard Atmosphere

JAR Joint Airworthiness Requirement

kg Kilogram

kg/m Kilograms Per Minute

kg/s Kilograms Per Second

kHz Kilo Hertz

kPa Kilopascal

kPaa Kilopascals Absolute

kPad Kilopascals Differential

kPag Kilopascals Gauge

kW Kilo Watt

L Liter

l/h Liters Per Hour

lb Pound

lbs/hr Pounds Per Hour

lbs/m Pounds Per Minutelbs/sec. Pounds Per Second

LC Load Compressor

LOP Low Oil Pressure

LP Low Pressure

LRU Line Replaceable Unit

LVDT Linear Voltage Differential Transducer

m Meter

mA Milliampere

MAX Maximum

MCDU Multi-function Control and Display Unit

MES Main Engine Start

MHz Mega Hertz

P Qts Quarts

MIN Minimum

mm Millimeter

MMEL Master Minimum Equipment List

MTBF Mean Time Between Failure



HSPS CT/NOV. 2006 Page vii




SIG Pounds Per Square Inch Gauge

MTBUR Mean Time Between Unscheduled Removals

mV Millivolt

N Rotation Speed

NGV Nozzle Guide Vane

NVM Non MemoryVolatile VAC Volts, Alternating Current

OAP Outside Air Pressure

OAT Outside Air Temperature

OBRM On Board Replaceable Memory

P/N Part Number

PCD Pressure Compressor Discharge

PMG Permanent Magnet Generator

PS Power Section

PSIA Pounds Per Square Inch Absolute

PSID Pounds Per Square Inch Differential

RAM Random Access Memory

ROM Read Only Memory

RPM Revolutions Per Minute

RTD Resistive Temperature Device

S Seconds

S/N Serial Number

SSLC Single Shaft Load Compressor

STS Status

THR Threshold

TRU Transformer Rectifier Unit

TSO Technical Standard Order

US G US Gallon

VDC Volts, Direct Current

°C Degrees Celsius

°F Degrees Fahrenheit

> Is Greater Than

< Is Less Than

± Plus or Minus

Ω Ohm

Δ Differential

% Percent



HSPS CT/ NOV. 2006 Page viii



APU LEADING PARTICULARS

WEIGHT 136 Kg (299 lbs) (dry)

OPERATING ALTITUDE -304.8 M to 11,887 M (-1,000 to 39,000 ft)

SEA LEVEL 15°C (59°F) STD DAY PERFORMANCE

OUTPUT SHAFT HORSEPOWER 399.7 Kw (536 HP)

ROTOR SPEED 100% (49,300 RPM)

ROTOR OVERSPEED (SHUTDOWN) 105% (51,765 RPM)

BACK UP OVERSPEED (SHUTDOWN) 107% (52,751 RPM)

ROTOR UNDERSPEED (SHUTDOWN) 95% (46,835 RPM)

BLEED AIRFLOW 1.8 kg/SEC (2.6 LBS/SEC)

BLEED AIR PRESSURE 290 kPag (42 PSIG)

FUEL CONSUMPTION 148 kg/HR (178 L/HR) [327 LB/HR (47 GAL/HR)]



HSPS CT/NOV. 2006 Page ix




EXHAUST GAS TEMPERATURE (SHUTDOWN)

START % SPEED EXHAUST GAS TEMPERATURE

0% 427°C (800°F)

10% 788°C (1450°F)

20% 899°C (1650°F)

30% 899°C (1650°F)

50% 853°C (1567°F)

80% 788°C (1450°F)

100% 670°C (1238°F)

RUN % SPEED EXHAUST GAS TEMPERATURE

100% 722°C (1332°F)



HSPS CT/NOV. 2006 Page x




GEARBOX SPEEDS Input 49,300 RPMGenerator 24,034 RPM (output)Fuel Control 10,129 RPM (output)Starter 32,045 RPM (output)

Cooling Fan 51,965 RPM (output)Oil Pump 4,137 RPM (output)

OIL PRESSURE 241 kPag (35 PSIG) (minimum)345-414 kPag (50-60 PSIG) (normal)

OIL CAPACITY 3.9 L (4.16 Qts) (add)5.4 L (5.72 Qts) (full)

OIL TEMPERATURE (SHUT DOWN) 135°C (275°F) Lubrication system185°C (365°F) AC Generator

APPROVED OIL SPECIFICATION:

MIL-PRF-7808

MIL-PRF-23699

CAUTION:

DO NOT MIX OR SUBSTITUTE OIL SPECIFICATIONS. USE ONLY ONE OF THE APPROVED OILS. IF THE OIL SUPPLY IS LOW AND THE OIL BEING USED IS NOT AVAILABLE, DRAIN THE OIL SUMP AND CHANGE THE OIL FILTER. SERVICE THEOIL SYSTEM WITH AN APPROVED OIL.



HSPS CT/NOV. 2006 Page xi




APPROVED FUELS

Fuel Type Specification Temperature Range

Jet A ATSM D1655 (NATO Code F-35)-35

°

C (-30°

F) to +57°

C (+135°

F)Jet A-1 ATSM D1655 (NATO Code F-35) -43°C (-45°F) to +57°C (+135°F)

Jet B ATSM D1655 (NATO Code F-45) -54°C (-65°F) to +57°C (+135°F)

JP-4 MIL-T-5624 (NATO Code F-40) -54°C (-65°F) to +57°C (+135°F)

JP-5 MIL-T-5624 (NATO Code F-44) -35°C (-30°F) to +93°C (+ 200°F)




HSPS CT/NOV. 2006 Page xii






.

HSPS CT/NOV. 2006 Page 1.0



SECTION 1

INTRODUCTION




HSPS CT/NOV.. 2006 Page 1.1



APS 3200- GENERAL PRESENTATION

Function

The APS 3200 is designed to provide compressed air and electricalpower to the aircraft on the ground and in flight.

- Electrical power supply to aircraft systems

- Compressed air supply to aircraft systems:

• Environmental Control System (ECS)• Main Engine Start (MES)• Various systems...

Requirements

Regulations: - JAR part 25, change 13- FAR part 25

Certification: - JAR APU change 2

Main Components

The main components are:

- The Auxiliary Power Unit (APU)

- The Electronic Control Box (ECB)

- The aircraft systems (Pneumatic system, Electrical system, Controlpanels).

The APU is a single spool gas turbine engine which drives a loadcompressor and an AC generator.

The ECB is an electronic contro ller, FADEC type (Full Authority

Digital Electronic Control).

Component Location

- The APU is installed in the tail section of the aircraft.

- The ECB is installed in the aft cargo compartment, right side,forward of the cargo door.

Control and Display

- On the overhead panel for APU operation and fire control

On the ECAM (Electronic Centralized Aircraft Monitoring) for APUparameters display

On the external panel, under the nose section, for APU emergency-shut-down





.

AUXILIARYPOWER UNIT

CONTROL ANDDISPLAY PANELS

ELECTRONICCONTROL BOX(AFT CARGOCOMPARTMENT)

AIRBUS AIRCRAFT




.




APS 3200 - DESCRIPTION (1)Power Unit

The APU consists of a gas turbine engine (Power Section) whichdrives:

- A load compressor

- And an AC generator (alternator) through a gearbox.

The APU is of modular design. It has three modules:

- The power section

- The load compressor

- The gearbox.

A common air inlet supplies the load compressor, the cooling fan andthe power section.

Power Section

The power section is a single spool gas turbine engine which

consists of:

- A centrifugal compressor

- A reverse flow combustor chamber

- A two stage axial flow turbine.

Load Compressor

The load compressor is a single stage centrifugal compressor drivendirectly by the power section. Variable inlet guide vanes are used forairflow and exhaust gas temperature control.

Gearbox

The gearbox, also driven by the power section, is attached to theload compressor. The gearbox provides the drive at the correctspeed for the AC generator and the APU mechanically drivenaccessories.

Electronic Control Box

The ECB provides control and monitoring of the APU and is locatedin the aircraft rear cargo compartment.



.



COMBUSTOR


AC GENERATOR

GEARBOX

LOADCOMPRESSOR

IMPELLER

TURBINES

APS 3200 – DESCRIPTION (1)



.





- The APU air inlet plenum is connected to the aircraft air intakesystem.

The APU air inlet plenum has a screen to protect the APU internal

components from foreign object damage.

- The cooling fan assembly is located at the top of the gearboxfront face.

- The starter motor drives the APU rotor assembly during starting.

The starter motor is located on the front face of the gearbox.

- The fuel control unit supplies and meters fuel to the APU. It islocated on the gearbox front face.

- The load compressor scroll houses the load compressorimpeller.

- The air inlet plenum delivers air to the impellers.

The air inlet plenum is located between the load compressor andthe power section.

- The ignition exciter supplies high energy electrical power to the

ignitor plugs.

The ignition exciter is mounted on the left side of the air inletplenum.

- The oil cooler transfers the heat of the lubricating oil to the coolingair supplied by the cooling fan assembly.

- The APU exhaust system delivers the APU exhaust gases to the

aircraft exhaust pipe.





COOLING FAN ASSEMBLY


APS 3200 - DESCRIPTION (2)

AIR BYPASSPLENUM

OIL COOLER

AIR INLETPLENUM

EXCITER

LOAD COMPRESSORSCROLL

APU AIRINLET

FUEL CONTROLUNIT

STARTERMOTOR






APS 3200 - DESCRIPTION (3)Identification of Components

- The gearbox provides the drive for the AC generator and theaccessories for APU operation.

The gearbox also provides the sump for the oil system.

- The AC generator that provides electrical power for the aircraftsystems.

- The cooling fan assembly for airflow through the oil cooler andventilation of the APU compartment.

The cooling fan assembly is located on the gearbox front face.

- The APU drain collector . The collector is installed on the rightside of the gearbox by two struts.

- The air- bleed system that includes a servo valve, an actuator,and a bleed control valve.

- The inlet guide vane system that includes a servo valve, anactuator, the inlet guide vanes and their control mechanism.

- The combustor housing that houses the combustor chamber.

- Main and pilot fuel injection system installed on the combustorhousing.



.



MAIN AND PILOTFUEL INJECTIONSYSTEM


INLETGUIDE VANE

ACTUATOR

BLEED CONTROLVALVE



APU DRAINCOLLECTOR

GEARBOX

AC GENERATORMOUNTING PAD



.



APS 3200 - OPERATION

Power section provides the shaft power to drive the loadcompressor and the gearbox.

Power is produced by transforming the energy contained in theambient air and the fuel through thermodynamic cycle: compression,combustion, expansion.

- Compression of the air in the single stage centrifugal compressor

- Combustion of the air-fuel mixture in the reverse flow combustorchamber

- Expansion of the burned gases across the two stage axial flowturbine to drive:

• The power section impeller

• The load compressor impeller

• The gearbox.

The load compressor supplies compressed air to the aircraftpneumatic system. The air is compressed by a single stagecentrifugal impeller and uses variable inlet guide vanes to control the

air flow. The compressed air is delivered through a scroll to the bleedcontrol valve.

The gearbox provides the drive for the AC generator, andaccessories for APU operation.

The AC generator that provides electrical power for the aircraftsystems.

The Electronic Control Box receives various signals from theaircraft and the APU to operate and monitor the APU.

The electronic control box controls the following:

- Rotation speed (N) (fuel flow)

- Load compressor surge protection (bleed control valve)

- Exhaust Gas Temperature (EGT) (inlet guide vanes).






TO AIRCRAFT

TO APUEXHAUST

POWER SECTION



ECB

BLEED CONTROL

VALVE

COMPRESSION COMBUSTION EXPANSION

GENERATOR

AMBIENT AIRCOMPRESSED AIRCOMBUSTIONEXHAUSTFUEL FLOWELECTRICAL SIGNALS

IGV ACTUATORFUEL CONTROL

EXHAUST

GEARBOX

LOAD COMPRESSOR









HSPS CT/NOV..2006 Page 2.0



SECTION 2

POWER UNIT




.




POWER UNIT - GENERAL

Function

The APU provides compressed air and electrical power to the aircraft.

Location

The APU is installed in the aircraft tail section.

Type

Single spool gas turbine engine driving a load compressor and an ACgenerator.

Main Characteristics

Characteristics at Aero Design Point, installed APU (ISA, sea level) aregiven for information only:

- Total power ............................400 kW (536 HP)

- Specific fuel consumption .......0.372 kg/kW.h (0.61 Ib/HP.H)

- Fuel consumption ...................148 kg/HR (178 L/HR)

................................................[327 LB/HR (47 GAL/HR)]- Electrical power ......................132 kW (177 HP)

- Pneumatic power ...................252 kW (338 HP)

- Bleed air flow .........................1.2 kg/sec. (2.6 lbs/sec.)

- Bleed air pressure ..................390 kPa (42 PSI)

- Rotation speed .......................49 300 RPM

- Direction of rotation ................clockwise (view from the rear)

- APU dry weight ......................136 kg (299 lbs).

Main Components

- Gearbox (with AC generator and APU accessory drive)

- Load compressor (centrifugal type provided with inlet guide vanes)

- Air inlet plenum (air intake and air dist ribution)

- Power section including:

• A centrifugal impeller

A reverse flow combustor chamber

• A two stage axial flow turbine.





LOADCOMPRESSOR

CENTRIFUGALCOMPRESSOR



GEARBOX AIR INLETPLENUM

TURBINES

AC GENERATOR

COMBUSTORCHAMBER

ECB



.




POWER UNIT - DESCRIPTION (1)

The first part of the description deals with the APU rotating assemblyand the second part will consider the modular design of the APU.

The following main components are considered in this description:

gearbox, air intake plenum, load compressor and power section.

Gearbox

The gearbox located at the front of the APU provides the mechanicaldrive for the AC generator and the accessories required for the APUoperation. The oil sump is also part of the gearbox.

Load Compressor

The load compressor is driven by the power section and providescompressed air to the aircraft pneumatic system. It is a centrifugalimpeller that has variable inlet guide vanes to control the air flowoutput.

Air Inlet Plenum

The plenum is located between the load compressor and the power

section. The plenum directs the air supply to the power section, loadcompressor and the oil cooling system.

Power Section

The power section provides mechanical shaft power to drive the loadcompressor and the gearbox.

The power section comprises:

- A single stage centrifugal impeller

- A reverse flow combustion chamber

- A two stage axial flow turbine

- An exhaust system.

The main rotor assembly is supported by two bearings: A ballbearing at the front of the load compressor, a roller bearing at therear of the turbine.



.



DRIVE TRAINFOR AC GENERATOR

AND APU ACCESSORIESCENTRIFUGALIMPELLER COMBUSTION

CHAMBERFRONTBEARING

EXHAUST



OILSUMP

CENTRIFUGALIMPELLER

AIR INLETPLENUM

TURBINES

REARBEARING

VARIABLEINLET GUIDEVANES





.



POWER SECTIONIMPELLERLOAD COMPRESSOR

IMPELLER

FRONT BALLBEARING



QUILL

INTERSHAFTTIE

BOLT

SECURINGNUT

TURBINES

REAR ROLLERBEARING

SECURINGNUT

A320-457a



.


HAMILTON SUNDSTRAND PROPRIETARYUse or disclosure of this data is subject to therestriction on the title page of this document.

POWER UNIT - OPERATION

General

The power section produces mechanical shaft power for APUoperation.

This mechanical power is used to drive:

- The load compressor which supplies compressed air

- The AC generator which supplies electrical power

- Accessories required for the operation of the APU.

Power Section Operation

The air enters the power section through the aircraft air inlet and the APU plenum.

In the plenum, this air is divided into two flows; one for the loadcompressor and one for the power section.

The power section air is directed to the centrifugal impeller which

increases the air pressure.

The air is then admitted to the combustion chamber, mixed with thefuel and burned to provide a continuous combustion process. Thegases are expanded across the turbines that transforms the gasenergy into mechanical energy.

The gases are then expelled overboard through the aircraft exhaustsystem.

Load Compressor Operation

The load compressor is driven by the power section and produces airflow to the aircraft pneumatic systems.

Gearbox Operation

The gearbox is driven by the power section to operate the APUaccessories and the AC generator.

Electronic Control Box (ECB)

The ECB provides control and monitoring of the APU.



.



BLEEDCONTROLVALVE

COMPRESSED AIR TO EXHAUSTCOMPRESSED

AIR TO AIRCRAFT

AC GENERATOR

ECB AMBIENT AIRCOMPRESSED AIRCOMBUSTION

EXHAUST



A320-458a



.



GEARBOX - GENERAL

Location

The gearbox is located at the front of the load compressor scroll.

Main Features

- Modular design

- Mechanical efficiency: 0.98

- Weight: 17 kg (37.4 lbs)

- Oil sump

- Gearbox drive power: 148 kW (198 HP)

- AC generator drive power: 132 kW (177 HP)

- Accessories drive power: 16 kW (21 HP)

- Material for housing: Aluminum alloy.

Gearbox Front Face View

- Oil cooling fan drive pad

- AC generator drive pad

- Starter motor drive pad

- Fuel control unit drive pad

- Accessories (oil filters, oil level sensor, de-oiling valve...).

Gearbox Left Side View

- Oil sight glass

- Oil fill tube

- High oil temperature sensor

- Speed sensor

- Gearbox mounting flange (attachment with the load compressorscroll)

- APU front left mount.



.



COOLING FAN

MOUNTINGFLANGE AC GENERATOR


GEARBOX - GENERAL

APU FRONTMOUNT

FWD

OIL FILLTUBE

OIL SIGHTGLASS

HIGH OIL TEMPERATURE

SPEEDSENSOR

DE-OILINGVALVE

OIL LEVELSENSOR

OILFILTERS

STARTER MOTOR

FUEL CONTROL

DE-OILING

VALVE

A320-459a



.



GEARBOX DESCRIPTIO (1)

This description considers the gears, the bearings and the drivepads.

Gears

The gearbox comprises of 8 spur type gears made of steel alloy. Thegear train provides the correct speeds for the APU driven units.

BearingsThe gears are supported by bearings: 6 roller bearings and 6 ballbearings.

AC Generator Drive- Speed: 24034 RPM- Direction of rotation: Clockwise.

Intermediate Gear- Speed: 14349 RPM- Direction of rotation: Clockwise- Centrifugal air-oil separator.

Cooling Fan Drive- Speed: 51965 RPM

- Direction of rotation: Anti clockwise- PMG (Permanent Magnet Generator).

Starter Motor Drive- Speed: 32045 RPM- Direction of rotation: Anti clockwise- Starter clutch: Sprag type.

Fuel Pump Drive- Speed: 10129 RPM-Direction o f rotation: Clockwise.

Oil Pump Drives- Lubrication pump

• Speed: 4137 RPM• Direction of rotation: Clockwise.

Scavenge pumps• Speed: 4137 RPM

Direction of rotation: Anti clockwise.

Note: Direction of rotation by viewing the front of the gearbox.



.



-

FRONT VIEWCOOLING FANDRIVE(51965 RPM)

INTERMEDIATEGEAR(14349 RPM)

STARTER MOTORDRIVE(32045 RPM)

AC GENERATORDRIVE(24034 RPM)


GEARBOX - DESCRIPTION (1)

DRIVEGEAR(49300 RPM)

FUEL PUMPDRIVE(10129 RPM)

OIL PUMPDRIVES(4137 RPM)



.




Identification of Gearbox Components

- The gearbox housing which forms the oil sump and provides theaccessories for the oil system (oil filter, oil level sensor, magnetic

plug...).

The gearbox housing also provides the mounting pads for:

• The oil cooling fan

• The AC generator

• The starter motor

• The fuel control unit

The gearbox housing is attached to the load compressor scroll bya mounting flange.

- The APU front left and right mounts are located on the sides ofthe gearbox.

- The gearbox gear train which includes:

• The AC generator drive gear

• The intermediate gear, which also forms the air-oilseparator

• The starter motor drive gear

• The fuel control unit drive gear

• The oil pump drive gears.



.

HSPS CT/NOV. 2006 Page 2.14HAMILTON SUNDSTRAND PROPRIETARY

INTERMEDIATEGEAR AC GENERATOR

DRIVE GEAR

STARTER MOTORDRIVE GEAR



DRIVEGEAR

FUEL CONTROLUNIT DRIVEGEAR

OIL PUMPDRIVE GEARSGEARBOX GEAR TRAIN

A320-461a



.



GEARBOX - OPERATION

During Starting

The starter motor is electrically energized and provides the torque tocrank the gear train and the APU rotor assembly.

At self-sustaining speed, the electrical supply to the starter is de-energized and the starter is disengaged by the sprag clutch.

Normal Running Condit ion

The power section provides the mechanical power to drive the loadcompressor and the gearbox drive gear.

The drive gear meshes directly with the AC generator gear.

It also drives an intermediate gear which in turn drives the oil coolerfan gear, the starter motor gear and the fuel control unit and oil pumpgears



HSPS CT/NOV..2006 Page 2.16HAMILTON SUNDSTRAND PROPRIETARY

AC GENERATORDRIVE

COOLINGFAN GEAR

DRIVE

GEAR INTERMEDIATEGEAR

DRIVENGEAR

STARTERDRIVE GEAR

FUEL CONTROL

UNIT DRIVE GEAR

DRIVEGEAR


GEARBOX - OPERATION

RUN OPERATIONOIL PUMPDRIVE GEARS

START OPERATION

A320-461a



.



AIR INLET PLENUM - GENERAL

Location

The inlet plenum is located between the load compressor and thepower section.

Main Features

- Acoustically treated part

- Shop replaceable unit

- Weight: approx. 7.5 kg (16.5 lbs).

Main Components

The plenum consists of two parts, upper and lower, which areconnected by quick disconnect latches.

The lower part interfaces with the aircraft air inlet system. The airinlet to the plenum is provided with a screen made of stainless steelthat protects the APU internal components from foreign objectdamage.

The upper part has an outlet for air supply to the oil cooling system(supply to the oil cooler fan).

Construction

The plenum is of sandwich construction with a structural envelope,Nomex and felt metal. The structural envelope and Nomex are fire

proof.

Operation

In the plenum, the air is separated into two flows by the splitter.

- One for the power section: 2.2 kg/s (4.8 lbs/sec.)

- One for the load compressor and cooling fan: 1.2 kg/s (2.6lbs/sec.).



.


COOLING FAN

AIR SUPPLY

QUICK DISCONNECTLATCHES



LOADCOMPRESSORIMPELLER SPLITTER SCREEN

AMBIENT AIRCOMPRESSED AIR

A320-463a



.



AIR INLET PLENUM - DESCRIPTION

Identification of the Air Inlet Plenum Components

- The lower part of the air inlet plenum interfaces with the APU airinlet system. It has a screen to protect the APU internal


The lower part incorporates noise treatment and a splitter whichseparates the air into two flows. It also provides the support for thefollowing components:

• The ambient air pressure and temperature sensors

• The differential pressure sensor

• The low oil pressure switch

• The ignition exciter.

- The upper part of the air inlet plenum is also noise treated.

The upper part has an oval outlet to supply air to the oil coolingsystem

- The quick disconnect latches secure the upper part and lowerpart of the air inlet plenum.



.


PLENUMUPPER PART

SPLITTER



A320-464a

AIR INLETHOUSING

PLENUMLOWER PART

QUICKDISCONNECTLATCH

COOLING FAN AIR SUPPLY

INLETSCREENLOCATING

TAB



.



LOAD COMPRESSOR - GENERAL

Location

The load compressor is installed between the gearbox and the powersection.

Type

High pressure centrifugal impeller provided with inlet guide vanes.

Main Features

- Air flow: 1.2 kg/s (2.6 lbs/sec.)

- Pressure ratio: 4:1

- Max outlet temperature: 232°C (450°F)

- Rotation speed: 49 300 RPM

- Direction of rotation: clockwise (viewed from the rear of the APU).

Main Components

- Rotating components (compressor shaft, impeller, bearing,bearing seals)

- Stationary components (air inlet housing, variable inlet guidevanes, impeller shroud, diffuser, and scroll).



.


BLEED CONTROLVALVE

COMPRESSED AIRTO AIRCRAFT

COMPRESSED AIR TOEXHAUST



INLET GUIDEVANES

COMPRESSORIMPELLER

SCROLL


A320-465a



.



LOAD COMPRESSOR - DESCRIPTION (1)

The first part of this description deals with the load compressorcomponents, the second part will consider the inlet guide vanescontrol mechanism and the third part the identification of all thecomponents.

Air Inlet Housing

The housing allows the passage of air to the load compressor andsupports the inlet guide vanes. It is made of aluminum alloy.

Compressor Impeller

The impeller is constructed of titanium alloy. The rear shaft of theimpeller is connected to the rotor intershaft using a curvic coupling.The front is supported by a ball bearing.

Compressor Shroud

The shroud houses the impeller and is constructed of steel alloy.

Compressor Diffuser

It consists of 19 cambered vanes made of steel alloy.

Scroll

The annular scroll provides the air outlet of the load compressor. It iscast aluminum.

The scroll housing provides passages for static air pressure to theload compressor discharge pressure sensor.

Bearing

A ball thrust bearing supports the front shaft of the load compressor.It is mounted in the load compressor housing.

Bearing Seals

Oil that is used to lubricate the front bearing is prevented fromentering the impeller area by a floating carbon seal and a labyrinthseal.



.


COMPRESSOR

DIFFUSERDRAINSQUEEZEFILM THRUST

WASHER



COMPRESSORSHROUD

INLET GUIDEVANE

A320-450a

COMPRESSORIMPELLER

BALLBEARING FLOATING

CARBONSEAL

LABYRINTHSEAL

AMBIENT AIRCOMPRESSD AIR



.




Identification of Load Compressor Components

- The IGV assembly includes the variable inlet guide vanes, therack and pinion mechanism and the air inlet housing

- The compressor shroud houses the impeller.

- The load compressor impeller has main blades and splitterblades. The impeller is connected at the rear to the inter shaft bycurvic-coupling. The impeller front shaft is supported by the frontbearing.

- The scroll provides the air outlet of the load compressor. Thescroll also houses the load compressor diffuser.

- The front bearing is a ball bearing that supports the impeller frontshaft

- The labyrinth seal is pressurized with compressed air from thepower section impeller.

- The front bearing nut retains the front bearing and forms thephonic wheel of the speed sensing system

- The tie-bolt and the securing nut.



.


SCROLL

LABYRINTHSEAL



FRONTBEARING

FRONT BEARINGJOURNAL

TIEBOLTSECURING

NUT

FRONT BEARING NUT(PHONIC WHEEL)

INLET GUIDEVANE ASSEMBLY

COMPRESSORSHROUD

LOAD COMPRESSORIMPELLER






ACTUATORROD HOUSING AIR INLET

HOUSING


INLET GUIDEVANE CONTROLROD

INLET GUIDEVANE

ASSEMBLY

RINGGEAR

IGVPOSITIONINDICATOR

INLET GUIDE

VANE

SECTORGEAR

LOAD COMPRESSOR – DESCRIPTION (3)

A320-467A



.



LOAD COMPRESSOR - OPERATION

Air Inlet

The ambient air enters the APU through the aircraft air inlet and the APU plenum.

The plenum air is separated into three flows:

- Air for the power section

- Air for the oil cooling system

- Air for the load compressor.

The air for the load compressor passes through the inlet guidevanes; the flow of air depends upon the position (the angle) of thevanes. The air is then directed to the blades of the compressorimpeller.

Compression

As the air enters the blades of the rotating compressor impeller theair velocity increases.

The air leaves the tip of the blades at high velocity and flows throughthe diffuser vanes where velocity is transformed into pressure.

Delivery

The compressed air then flows into the scroll and delivered to the

pneumatic system through a bleed control valve.



.



COMPRESSED AIR TO AIRCRAFT

SCROLL



DIFFUSERVANE

COMPRESSORIMPELLER INLET GUIDE

VANES

A320-468a




.



POWER SECTION - GENERAL

Function

The power section provides the power to drive the load compressorand the gearbox.

Location

The power section forms the rear part of the APU.

Type

Single spool gas turbine engine.

Main Components

The main functional components are:

- Single stage centrifugal impeller

- Reverse flow combustion chamber

- Two stage axial flow turbine

- Exhaust.



.




TWO STAGE AXIAL FLOWTURBINES

SINGLE STAGECENTRIFUGALCOMPRESSOR

MAIN CHARACTERISTICS

POWER400 Kw (536 HP)

SPECIFIC FUEL CONSUMPTION0.372 kg/kW.h (0.61 lb/HP.H)

FUEL CONSUMPTION327 LB/HR (47GAL/HR)

ROTATION SPEED49300 RPM

AIR MASS FLOW2.2 kg/s (4.8 lbs/sec)

COMPRESSION RATIO8:1

EXHAUST

REVERSE FLOWCOMBUSTIONCHAMBER


A320-469a





.


IMPELLERCONTAINMENTSHIELD

COMPRESSORHOUSING

IMPELLERSHIELD

CURVICCOUPLINGCURVIC

COUPLING


POWER SECTION - COMPRESSOR - GENERAL

INTER SHAFTMAIN BLADES

SPLITTER BLADES



.



POWER SECTION - COMPRESSOR - DESCRIPTION

Identification of Compressor Components

- The intermediate shaft is connected to the front of the loadcompressor impeller and to the rear of the power sectioncompressor impeller by curvic-couplings.

- The compressor housing houses the impeller and thecompressor shield.

The compressor housing is attached at the front to the air inlethousing and at the rear to the diffuser assembly and the combustorhousing.

- The impeller containment shield is mounted to the compressor

housing.

- The impeller has main blades and splitter blades. The impeller isconnected at the front to the intermediate shaft and at the rear tothe turbine by curvic-couplings.

- The diffuser is mounted to the impeller shield.



.




COMPRESSORHOUSING


INTERMEDIATESHAFT

DIFFUSER

IMPELLER IMPELLERSHIELD

POWER SECTION – COMPRESSOR - SECTION

a320-471a





.


AIRCOMBUSTORTUBESHOUSING

FUEL


POWER SECTION - COMBUSTOR CHAMBER - GENERAL

INJECTOR

IGNITER

COMBUSTOR

CHAMBERBEND ASSEMBLY

HEATSHIELD TURBINE

CONTAINMENTSHIELD

A320-472a



.



POWER SECTION - COMBUSTOR CHAMBER -DESCRIPTION

Identification of Combustor Chamber Components

- The combustor housing houses the combustor chamber. It alsohas bosses for the mounting of the fuel injectors, the igniter plugsand the combustor chamber drain valve.

- The combustor chamber has holes and tubes that allows air usedfor combustion and cooling to enter the combustor chamber.

- The bend assembly guides the burned gases from the combustorchamber to the inlet of the first stage turbine nozzle guide vane.

- The heat shield protects the diffuser holder plate of the powersection impeller.

The heat shield is located between the bend assembly and thediffuser assembly.

- The combustor chamber drain valve is threaded into the bottomof the combustor housing, this allows unburned fuel to drainoverboard. The valve is closed by air pressure in the combustorhousing.

.





POWER SECTION - COMBUSTOR CHAMBER - DESCRIPTION

HEATSHIELD

BEND ASSEMBLY

FIRST STAGETURBINE NOZZLE

COMBUSTORCHAMBER

COMBUSTORCHAMBER DRAINVALVE

COMBUSTORHOUSING

COMBUSTOR AIR PRESSURE



.




FIRST STAGE SECOND STAGENOZZLE GUIDETURBINE WHEEL


POWER SECTION - TURBINE - GENERAL

FIRST STAGENOZZLE GUIDEVANE

VANE

CONTAINMENTSHIELD

SECOND STAGETURBINE WHEEL

CURVICCOUPLINGS

ROLLER TIEBEARING BOLT

A320-474a

.





POWER SECTION - TURBINE - DESCRIPTION

Identification of Turbine Components

- The first stage nozzle guide vane has 22 vanes installed in frontof the first stage turbine wheel

- The first stage turbine wheel has 37 fir tree blades inserted into adisc and secured by blade locks.

The turbine wheel is connected to the rear of the power sectionimpeller and to the second stage turbine wheel by curvic-couplings

- The second stage nozzle guide vane has 26 vanes installed infront of the second stage turbine wheel

- The second stage turbine wheel has 31 fir tree blades insertedinto a disc and secured by blade locks. Vibration dampers arefitted between the blades.

The turbine wheel is connected to the first stage turbine wheel by acurvic coupling.

The rear of the second stage turbine wheel is supported by a rollerbearing

- The containment shield is located around the turbine wheels.

- The turbine housing is located between the containment shieldand the turbine.

The turbine housing is connected to the exhaust housing.




FIR TREEBLADES



BLADELOCKS

VIBRATIONDAMPER


NOZZLE GUIDEVANE SUPPORT

FIRST STAGETURBINE WHEEL

CONTAINMENTSHIELD

TURBINEHOUSING

SECOND STAGENOZZLE GUIDEVANE

SECOND

STAGETURBINEWHEEL

A320-475a

.





POWER SECTION - EXHAUST - GENERAL

Function

The exhaust directs the exhaust gases to the aircraft exhaust pipe.

Location

The exhaust diffuser is located inside the APU exhaust housing.

Type

One piece, annular exhaust pipe.

Main Components

The exhaust housing is constructed of stainless steel and provides apassage for the exhaust gases. The housing also contains the rearbearing and struts that house oil pipes to the rear bearing.

.




FLOATING CARBON SQUEEZESEAL FILM



STRUT

DISCHARGE AIR

REAR

BEARING

AIR BYPASSPLENUM

LABYRINTHSEAL

ROLLERBEARING

FLEXIBLECAGE

EXHAUSTHOUSING

A320-451a

.





POWER SECTION - EXHAUST - DESCRIPTION

Identification of Exhaust Components

- The exhaust housing consists of an outer housing and diffusercone supported by struts.

The inner cone houses the rear bearing assembly and the rearbearing oil pipes.

- The rear bearing housing:

• The rear bearing

• The rear end of the tie-bolt

• The securing nut.

The rear bearing housing has threaded bosses for the mounting ofthe rear bearing oil pipes.

- The rear bearing o il pipes:

• The rear bearing oil supply

• The rear bearing oil scavenge

• The rear bearing oil venting.

- The rear bearing is a roller bearing, it is located inside the rearbearing cage.

- The rear bearing labyrinth seal is installed on the rear shaft ofthe second stage turbine wheel.

The labyrinth seal is pressurized by compressed air from thepower section compressor.

- The air bypass plenum is installed on the exhaust housing and isprovided with a drain connected to the drain system.




AIR BYPASSPLENUM

REAR BEARINGHOUSING

REAR BEARINGVENT PIPE

SECURINGNUT

EXHAUSTHOUSING

LABYRINTH



SEAL

REAR BEARING OILSUPPLY PIPE

REAR BEARINGSCAVENGE PIPE

REAR BEARING

TIEBOLT

CAGE

A320-476a

.





POWER SECTION - OPERATION (1)

The power section produces the shaft power through thethermodynamic cycle: compression, combustion, expansion andexhaust.

Compression

Ambient air is directed into the blades of the rotating impeller. The airthen flows through the divergent passages of the diffuser. (The airvelocity is transformed into pressure.)

Combustion

The compressed air is divided into two flows:

- A primary flow mixed with the fuel for combustion

- A secondary flow (dilution air) to cool the combustor and internalparts.

As a result of the continuous burning process, the pressuredecreases slightly whereas the velocity and the temperatureincrease.

Expansion

Expansion of the gases takes place across the two stages of theturbines, this transforms the gas energy into shaft power.

The gases flow through the nozzle guide vanes which increase thevelocity, then across the turbine blades. The aerodynamic forcescause the turbine wheels to rotate.

During expansion, the velocity of the gases increases and thepressure and temperature decrease.

Exhaust

The gases are then expelled overboard through the exhaust system.

.






AMBIENT AIRCOMPRESSED AIRCOMBUSTIONEXHAUSTFUEL

a320-477a

PRESSURE ANDTEMPERATUREVALUES ARE GIVEN

AT ZERO DESIGNPOINT FORINFORMATION

.






The power section provides air flow to pressurize the APU labyrinthseals, to cool internal heated parts and balance rotor forces.

Pressurization

- Pressurization of Labyrinth Seals

Labyrinth seals are supplied with air pressure. A pressuredifference across the seals provide a non contact seal.

- Pressurization of Load Compressor Front Bearing

The pressurized air, bled from the outlet of the power sectionimpeller, flows through an external pipe to the labyrinth seal of the

load compressor front bearing and the cooling fan labyrinth seal.

- Pressurization of Power Section Rear Bearing

The pressurized air, bled at the outlet of the power sectionimpeller, flows through the power section rotor assembly to therear bearing labyrinth seal.

Cooling

To prevent excessive heating of the parts subjected to thecombustion gases, a circulation of cooling air (bled at the outlet ofthe power section impeller) is provided through the power section

rotor assembly, and is directed by internal passages to the turbinewheel faces.

Balance of Forces

The shaft, the turbine wheels, and the compressor impellers aresubjected to axial forces resulting from the operation of the rotorassembly.

To reduce the forces on the bearings, air pressure is used on thebackside of the power section impeller.



.




APS 3200 AUXILIART POWER UNIT






SECTION 3

OIL SYSTEM






OIL SYSTEM - GENERAL

Function

The system is used to lubricate and cool the APU and the ACgenerator.

Location

The system components are all located on the gearbox except the oilcooler. The cooler is located on the left side of the APU.

Main Features

Self contained, full flow system.

- Max oil temperature: 135°C (275°F)

- Normal oil pressure: 345 - 414 kPa (50 - 60 PSIG)

- Low oil pressure: 241 kPa (35 PSIG)

- Oil quantity: 5.4 liters (5.72 Qts) at FULL mark

Lubrication and Cooling Requirements

- The APU rear bearing

- The APU front bearing

- The gearbox gears and bearings

- The AC generator

- Cooling Fan



HSPS CT/NOV.. 2006 Page 3.2HAMILTON SUNSTRAND PROPRIETARY

FRONTBEARING



REARBEARING

GEARBOX

GEARS ANDBEARINGS

LUBRICATION AND

COOLING OF AC GENERATOR

OIL SYSTEMMAIN FEATURES

MAX OIL TEMPERATURE135 C (275 F)

NORMAL OIL PRESSURE345 – 414 Kpa (50-60 PSIG)

LOW OIL PRESSURE241 KPa (35 PSIG)

OIL QUANTITY5.4 liters (5.72 Qts)

OIL SYSTEM COMPONENTSON GEARBOX

(EXCPT OIL COOLER)






OIL SYSTEM - DESCRIPTION

Oil Sump

The oil sump is formed by the lower part of the gearbox.

The gearbox has a fill tube for gravity filling, an overflow drain, apressure fill connector and a sight glass.

The gearbox intermediate gear also functions as the air/oil separatorand provides air venting of the gearbox.

Oil Pumps

One lubrication pump and two scavenge pumps are driven by thegearbox.

The pressure system is provided with a pressure relief valve locatedon the front of the gearbox.

Oil Filters

There is one filter in the lubrication line and one in the AC generatorscavenge line.

Both filters are the same and each have a filter element impendingblockage switch indicator. They are mounted on the lower front faceof the gearbox. The oil filter by pass valve for each filter is located inthe gearbox and is non adjustable.

Oil Cooler

The oil cooler cools the oil and has a by-pass valve.

De-oili ng Valve

The de-oiling valve is a solenoid valve located at the inlet of thepressure pump. When energized open, the valve prevents oil flowthus reducing the APU starting loads on the starter.

Monitoring Devices

- Low oil pressure switch


- AC generator high oil temperature sensor

- Oil level sensor

- Oil level sight glass

- Oil filter impending blockage switch indicator on each oil filterassembly

- Magnetic drain plug.






OIL SUMP

OIL PRESSUREOIL RETURN

AIR-OIL MIST

SCAVENGEPUMPS

OIL FILTERBYPASS VALVES

OIL FILTERSOIL LEVELSIGHT GLASS

AC GENERATOR

HIGH OILTEMPERATURESENSOR

LOW OILPRESSURESWITCH

PRESSURERELIEF VALVE

CHECKVALVE

CHECK VALVE

OIL COOLER

AIR OILSEPERATOR

LUBRICATIONPUMP

DE-OILINGVALVE

OIL LEVELSENSOR

OILFILLERTUBE

MAGNETICDRAIN PLUG


a 320-481a





OIL SYSTEM – OPERATION

The main functions of the oil system are : oil supply, scavengereturn, venting and indicating.

Oil Supply

The lubrication pump draws the oil from the sump and delivers it to

the oil system. During starting, the de-oiling valve opens and air isdrawn into the pump to prevent oil flow. After de-oiling the oil flows tothe oil cooler, then to the filter.In the event oil flow through the filter becomes restricted, the switchindicator is activated. If the filter becomes blocked, the oil filterbypass valve will open and allow flow to the oil system.The oil pressure relief valve opens to regulate the oil systempressure. When the valve is open, some of the oil flow is bypassedback to the inlet side of the lubrication pump.

Scavenge Return

After lubrication, the oil returns to the gearbox sump by twoscavenge pumps:- One for the power section rear bearing that returns the oil directly

to the sump- One for the AC generator that returns the oil to the sump through a

filter.Note: The front bearing and the gearbox are scavenged by gravity.

Scavenge Return

After lubrication, the oil returns to the gearbox sump by twoscavenge pumps:

-One for the power section rear bearing that returns the oil directly tothe sump

One for the AC generator that returns the oil to the sump through afilter.

Note: The front bearing and the gearbox are scavenged by gravity.

Venting

Oil mist in the gearbox is separated by a centrifugal air-oil separator.

The gearbox is vented to the exhaust through an external pipe.

Monitoring-Low oil pressure switch-High oil temperature sensor- AC generator high oil temperature sensor- Oil filter impending blockage switch indicators- Oil level sensor- Oil level sight glass- Magnetic drain plug



V



OIL SYSTEM - OPERATION

OIL SUPPLYOIL PRESSURESCAVENGE RETURN VENTING

a 320-481 aOIL SYSTEM - OPERATION





ENGINE LUBRICATION (1)

Lubrication is required for the AC generator, the gearbox and the APU bearings.

AC Generator Lubricat ion and Cool ing

Oil Supply

From the lubrication pump and filter, the oil is supplied to the ACgenerator:

- One flow for cooling

- A second flow to lubricate the generator drive shaft splines.

Scavenge and Return

The oil from the AC generator is scavenged by a pump and returnedto the gearbox sump through a filter.

Gearbox Lubrication

Oil Supply

The oil flowing from the lubrication pump passes through the filterand then by means of internal lines and jets is sprayed onto thegears and bearings.

From the gearbox the oil is also supplied to the cooling fan bearingsand to the rotor assembly front bearing.

Scavenge and Return

After lubrication the oil returns to the gearbox sump by gravity.





ENGINE LUBRICATION (1) AC GENERATOR LUBRICATION

GEARBOX LUBRICATION

AC GENERATORLUBRICATION

AND COOLING

AC GENERATOROIL SCAVENGE

FROM LUBRICATIONPUMP


DE-OILED AIR TO

EXHAUST

DE-OILED AIR TO

EXHAUST

AC GENERATORDRIVE SHAFT SPLINELUBRICATION

SPRAYJETS

TO LUBRICATIONPUMP

TO LUBRICATIONPUMP

OIL RETURNTO SUMP

OIL SUPPLYOIL PRESSURESCAVENGE RETURNVENTING

AC GENERATOR LUBRICATION

a 320-482 a






Front Bearing Lubrication

Oil Supply

The lubrication for the rotor front bearing is provided by pressurized

oil from the gearbox oil system.

A jet located in the gearbox housing sprays oil between the front endof the load compressor shaft and the front bearing nut. (PhonicWheel)

The oil runs along the shaft, lubricates the quill shaft splines andenters the gap through the split inner races to lubricate the bearing.

Oil flow to the bearing is also provided by oil passages between thegearbox and bearing outer race to provide a squeeze film to dampenbearing vibration.

Scavenge and Return

After lubrication the oil is returned to the sump by gravity.

Sealing

Oil sealing of this assembly is by a floating carbon seal and a

labyrinth seal using air from the power section impeller.

A drain cavity between the seals is vented overboard, into the APUdrainmast.




FLOATING AIR FROMCARBONSEAL

POWER SECTIONIMPELLER

SQUEEZEFILM

BALL BEARING


ENGINE LUBRICATION (2) - FRONT BEARING LUBRICATION

INTERNAL OILSUPPLY

FRONT BEARINGNUT

DRAINCAVITY

LOADCOMPRESSORIMPELLER

LABYRINTHSEALS

a 320-452 a

OIL PRESSURE SPRAYCOMPRESSED AIRSEA L AIR VENT







Rear Bearing Lubr ication

Oil Supply

The lubrication of the rotor rear bearing is provided by pressurized oilfrom the gearbox oil system.

The oil is supplied to the rear bearing through an external pipe.

In the bearing area, the oil is directed to the outer race to provide asqueeze film and an internal line that sprays oil into the rear tie-boltarea.

Drilled passages in the tie-bolt allow oil circulation for lubrication andcooling of the roller bearing.

Scavenge and Return

After lubrication, the oil is scavenged back to the sump through anexternal pipe by a scavenge pump.

Sealing

Oil sealing in the bearing area is accomplished by a floating carbonseal and a rotating labyrinth seal. The seals are pressurized with airflow from the power section impeller.




OIL SUPPLY

TIEBOLT

SQUEEZEFILM



ENGINE LUBRICATION (3) - REAR BEARING LUBRICATION

a 320-453 a

ROTATINGLABYRINTHSEAL

ROLLER

BEARING

AIR FROMPOWER SECTIONIMPELLER

FLOATINGCARBONSEAL

OIL PRESSUREOIL RETURNCOMPRESSOR AIR





OIL SUMP

Function

The sump provides a reservoir for the APU lubrication system.

Location

The sump is located in the bottom of the gearbox.

Main Features

- Capacity at the "FULL" mark: 5.4 litters (5.72 Qts)

- Capacity at the "ADD" mark: 3.95 litters (4.16 Qts)

Main Components

The main components of the oil sump are:

- Oil filler tube

- Oil overflow boss

- Oil pressure fill port

- Air-oil separator

- Magnetic drain plug

- Pressure relief valve

- Oil level sensor

- Oil level sight glass.




GEARBOX

OIL FILLERTUBE

OILOVERFLOWBOSS


OIL SUMP

OIL LEVELSENSOR

MAGNETICDRAIN PLUG PRESSURE

RELIEF VALVE

OILPRESSUREFILL PORT

OILLEVELSIGHTGLASS

GEARBOX – LEFT SIDE VIEWGEARBOX – FRONT VIEW

a 320-483 a





AIR-OIL SEPARATOR

Function

The air-oil separator separates the oil from the air.

Location

The air-oil separator is located in the upper part of the gearbox.

Description

The air-oil separator is part of the gearbox intermediate gear.

The gear has a hollow shaft with radial drillings. The rear of thehollow shaft vents into a passage in the gearbox housing.

Operation

An air-oil mist is created in the gearbox when the APU is operating.

The oil is separated from the air by the rotating action of the gearboxintermediate gear. The oil returns to the gearbox sump by gravityand the air is vented through a pipe to the APU exhaust.





AIR-OIL SEPARATOR

INTERMEDIATEGEAR

AIR-OILSEPERATOR

OIL RETURNTO SUMP

OIL MISTDE-OILED

AIR

TO APUEXHAUST

OIL RETURN

TO SUMP

AIR – OIL SEPERATOR

OIL PUMPS - GENERAL OIL PUMPS - DESCRIPTION





Function

One pump is used for the lubrication supply and two pumps forscavenge.LocationThe oil pumps are located inside the gearbox front face.

Main Features- Lubrication pump

• Type: Vane type• Flow: 2160 l/h (570 GPH)

- AC generator scavenge pump• Type: Vane type pump• Flow: 2160 l/h (570 GPH)

- Rear bearing scavenge pump• Type: Gerotor type pump

• Flow: 160 l/h (42 GPH)

Gerotor Type

The gerotor is a positive displacement pumping unit consisting of twoelements: an inner and outer rotor.The inner rotor has one less tooth than the outer, and has itscenterline positioned at a fixed eccentricity from the centerline of the

outer element.The inner element is driven by the gearbox.Vane TypeThe vane type pump consisting of a slotted inner rotor equipped withvanes operating in an eccentric housing.Operation of the Pressure Relief ValveThe oil pressure relief valve is a non adjustable, spring loaded reliefvalve.The valve will open when oil pressure reaches 345-414 kPag (50-60

PSIG). The oil that is bypassed, returns to the inlet of the lubricationpump.

AC GENERATOR




AC GENERATORSCAVENGE PUMP

FUEL CONTROLUNIT DRIVE


OIL PUMPS - GENERAL - DESCRIPTION

OIL SCAVENGE

PUMPS

OIL PRESSURE

PUMP PRESSURERELIEF VALVE

OIL PUMPDRIVE GEARS

REAR BEARINGSCAVENGEPUMP

LUBRICATIONPUMP

a 320-485 a





DE-OILING VALVEFunction

The de-oiling valve reduces the APU starting lead during startconditions.

Location

The valve is located on the left side of the gearbox.

Main Features

- Solenoid valve operated by the ECB

- Nominal rating: 28 VDC; 1.0 amps

- Solenoid valve energized open.

Description

The de-oiling valve is a solenoid operated valve directly controlled bythe ECB.

Operation

During the APU start up the de-oiling valve is energized open by theECB. When the valve is open the lubrication pump is prevented frompumping oil into the system. This reduces the starting load of the

APU and allows faster acceleration.

When the APU accelerates to 55% speed, the ECB de-energizes thede-oiling valve and allows the lubrication pump to produce oil flow.

During shutdown, the de-oiling valve is again energized by the ECBwhen the APU de-accelerates to 90% speed. This allows the oilremaining in the system to return to the oil sump with the exceptionof one quart remaining in the oil cooler.





DE-OILING SYSTEM

DE-OILING VALVE

AIR

GEARBOX LEFT SIDE

TOOIL

OIL SUMPCOOLER

OILFROM

TOLUBRICATION

PUMP

AIR

SUMPDE-OILING VALVE

a 320-486a

DE – OILING SYSTEM

OIL FILTERS - GENERAL OIL FILTERS - DESCRIPTION





Function

The function of the oil filters is to filter the oil.

There are two filters: one for lubrication and one for the AC generatorscavenge. They are the same type of filter.

Location

The lubrication filter is located in the pressure line after the oil cooler.The scavenge filter is located after the AC generator scavengepump.

Both filters are installed at the bottom front face of the gearbox.

Main Features

- Filter element: 20 microns

- By-pass valve setting: 345-414 kPad (50-60 PSID)

- Switch indicator setting: 207-241 kPad (30-35 PSID).

Each filter system consists of:

- A 20 micron disposable cartridge

- An oil filter impending blockage switch indicator

- A by-pass valv




LUBRICATIONFILTER

SWITCHINDICATOR

AC GENERATORSCAVENGE FILTER


OIL FILTERS - GENERAL - DESCRIPTION

LUBRICATIONFILTER

a 320-487 a





OIL FILTER - OPERATION

Oil Flow

In normal operation the oil is filtered and then flows to the oil system.

Pre-blockage of the Oil Filters

Should the filter become contaminated, a difference in pressureacross the filter will occur.

Two switch indicators are mounted on the front of the gearbox neareach oil filter. The switch indicator provides a visual indication whenthe oil temperature is 74°C (165°F) and the oil pressure across thefilter reaches 241 kPad (30-35 PSID). The ECB also monitors eachswitch indicator and will store the fault message.

By-pass

When the differential pressure across the filter exceeds 345 to 414kPad (50 to 60 PSID), the by-pass valve will open and allowunfiltered oil to flow into the system.

The by-pass valve is located in the gearbox and is non-adjustable.






a 320-488 a


OIL COOLER - GENERAL OIL COOLER - DESCRIPTION





Function

The oil cooler transfers the heat of the lubr icating oil to the airflowing through the cooler.

Location

The oil cooler is installed on the left side of the APU.

In the oil system, the cooler is located between the lubrication pumpand the filter.

Main Features

- Oil cooling ability: 2160 l/h (540 GPH)

- Oil cooler by-pass valve setting:

• Opening threshold: 207 kPad (30 PSID)

• Fully open: 345 kPad (50 PSID).

The oil cooler is a rectangular unit which includes:

- An oil cooler housing which consists of an integrally brazedaluminum heat-exchanger with an aluminum core and a stainlesssteel housing.

- A check valve and a by-pass valve to regulate the oil flow and

internal pressure of the oil cooler.A drain plug to drain theoil cooler




OIL COOLER – GENERAL - DESRIPTION

a 320-489 a


OIL COOLER - OPERATION





Normal Operation

The oil delivered by the lubrication pump flows through the aluminumcooling tubes that are cooled by the cooling fan air flow.

The cooled oil then flows to the various APU lubrication points.

By-pass Operation

When the pressure exceeds 207 kPad (30 PSID), the bypass valveopens.

The oil flow by-passes the cooler to the lubrication system.

Check Valve Operation

The check valve is an oil pressure operated valve.

When the pressure in the oil system is low (de-oiling during start andshutdown), the check valve closes and prevents draining of the oilcooler into the sump.

The check valve traps approximately one quart of oil in the oil cooler

when the APU is not running.

Air Flow

The oil cooler uses the airflow from the cooling fan to remove heatfrom the oil. The heated air is then discharged overboard through anair duct located in the left APU compartment service door.

COOLING AIRINLET

COOLING AIRINLET






OIL FLOW AIR FLOW

NORMAL

OPERATION

BY-PASSOPERATION

CHECKVALVE

OILOUTLET

OILOUTLET

CHECKVALVE

OIL FLOWRESTRICTION

OILINLET

OILINLET

BY-PASSVALVE CLOSED

BY-PASSVALVE OPEN

a 320-490 a

MONITORING DEVICES - LOW OIL PRESSURE SWITCHGeneral





Function

The Low Oil Pressure (LOP) switch senses the pressuredownstream of the filter.

The LOP switch initiates automatic APU shut down when the oilpressure is too low.

Location

The LOP switch is mounted on the right side of the air inlet plenumor on the lower right side of the gearbox

Main Features

- LOP switch setting: 241 kPag (35 PSIG)

- Output signal to ECB: ground signal.

Interfaces

- The ECB

- The APU oil system.

Functional Description

The LOP switch consists of a normally closed switch and is openwhen normal oil pressure is present.

The ECB does not check for oil pressure until the APU has reacheda speed of 100% (RTL) plus 10 seconds.

If oil pressure is below 241 kPag (35 PSIG), and the APU isoperating at 100% speed, the APU will shut down after running for10 seconds.




LOW OIL PRESSURE SWITCH

MONITORING DEVICES

a 320-491 a


MONITORING DEVICES - OIL TEMPERATURE SENSOR

General Functional Description





General

Function

The Oil Temperature (HOT) sensor senses the temperature of the oilat the outlet of the oil cooler. When the oil temperature is too high,

the HOT sensor initiates automatic APU shut down.

Location

The HOT sensor is installed on the lower rear face of the gearbox.

Main Features

- HOT sensor setting: 135° C (275° F)

- Sensor input signal (from ECB): 1 mA

- Sensor output signal (to ECB): variable output voltage

- 100 Ω RTD; 1 mA; 19°C to 149°C (67°F to 300°F.)

Interfaces

- The ECB



The HOT sensor is a Resistive Temperature Device (RTD) suppliedwith a constant current of 1 mA (by the ECB). The resistance varieswith the oil temperature and modifies the sensor output voltage.

When the oil temperature reaches a limit value of approximately135°C (275°F), the ECB will initiate automatic APU shut down.

Note: The AC generator also has an integral oil temperaturesensor which causes the APU to shut down when anexcessive temperature is detected (180°C; 365°F). Thesensor is monitored by the ECB.




ECB

TO AIRCRAFT

RESISTIVETEMPERATUREDEVICE(135C / 275F)


MONITORING DEVICE

a320-491 a

3 WAYSOLENOID VALVEGEARBOX LEFT SIDE

HOT SENSOR

OIL SUMP

OIL COOLEROIL FILTER

FROMOIL

COOLER

TOOIL

FILTER

HOT SENSOR

OIL TEMPERATURE SENSOR

MONITORING DEVICES - OIL LEVEL SENSORGeneral Functional Description





Function

The oil level sensor measures the quantity of oil in the gearboxsump.

When the oil level is too low, the sensor provides a flight deckwarning of low oil quantity on the lower ECAM, APU systems page.

Location

The oil level sensor is located on the right side of the gearbox.

Main Features


- Sensor output signal (to ECB): variable output voltage.

Interfaces

- The ECB


The oil level sensor is a Resistive Temperature Device (RTD) thatthe ECB supplies with a constant current of 75 mA.

The resistance varies with the oil level and changes the sensoroutput voltage sensed by the ECB.

At power up, the oil level is checked for a period of 8 seconds and isdetermined OK or LOW by the ECB.

If the oil level is low, the ECB will display "OIL QTY LOW" messageon the lower ECAM when the APU system page is selected.




MONITORING DEVICES

GEARBOX FRONT VIEW

a320-493a

OIL LEVEL SENSOR

Use or disclosure of this data is subject to the

restriction on the title page of this document.

MONITORING DEVICES

Oil Level Sight Glass

MAGNETIC DRAIN PLUG

A drain plug is located on the lower front side of the gearbox






The oil level sight glass is located on the lower left side of thegearbox housing, close to the oil fill tube.

It provides a visual indication of the oil level in the sump.

Oil level ADD and FULL marks are written on the sight glass.

housing. Removing the plug allows oil drainage from the sump. Thedrain plug embodies a magnetic chip detector that attracts ferrousmetal particles in the oil. The detector can be removed, inspectedand installed without draining the oil sump.

A self sealing valve in the drain plug housing prevents oil drainagewhen the magnetic chip detector is removed.




GEARBOXLEFT SIDE

GEARBOXFRONT VIEW

OIL LEVEL SIGHT GLASS MAGNETIC DRAIN PLUG

OIL LEVEL SIGHT GLASS - MAGNETIC CHIP DETECTOR

a320-494aMONITORING DEVICES



OIL PIPES

External Pipes






Supply

- From lubrication pump, oil cooler and to the gearbox

- From gearbox to power section rear bearing.

Scavenge

- From power section rear bearing to scavenge pump.

Vent

- From power section rear bearing to air-oil separator

- From air-oil separator to APU exhaust system.






OIL PIPES

OIL PRESSURE

OIL SCAVENGEVENT a320-495a

OIL PIPES











SECTION 4

FUEL SYSTEM



FUEL SYSTEM - GENERAL

Function Components Location






The fuel system provides the supply and the control of fuel to the APU under all operating conditions.

Systems Involved

- The aircraft fuel system

- The pneumatic system

- The APU control system

- The APU fuel system.

APU Fuel System Main Components

- Fuel control unit

- Flow divider

- Pilot fuel manifold and injectors

- Main fuel manifold and injectors.

- The fuel control unit is located on the front face of the gearbox

- The flow divider is located on the combustor housing

- The fuel manifolds and injectors are located on the combustorhousing.



HSPS CT/NOV.. 2006 Page 4.2HAMILTON SUNDSTRAND PROPRIETARY




FUEL SUPLYUN-METERED FUELMETERED FUELFUEL RETURN

FUEL SYSTEM - DESCRIPTION

The system consists of a fuel control unit, a flow divider and fuel




manifolds and injectors.

Fuel Control Unit

The fuel control unit contains the following injector components:

- Low fuel pressure switch (aircraft supplied)

- Low pressure pump (centrifugal type)

- Filter (filter element, by-pass valve and impending blockage ΔPindicator)

- High pressure pump (gear type pump);

- Servo valve (electrically operated valve that meters the fuel flow inresponse to signals from the electronic control box)

- Constant P valve (pressure differential valve that controls thedifferential pressure across the servo valve)

- 3 way solenoid valve (valve operated by the electronic controlbox to open and close the fuel supply to the fuel injectors).

- Pressure regulator (fuel pressure supply to the actuators of theair control system).

Flow Divider

The flow divider controls the flow to the main and pilot injectors. The

divider also provides pilot purge to the exhaust.

Main Fuel Manifold and Injectors

- Manifold to supply fuel to the main injectors

- Main in jectors (six injectors mounted on the combustor housing).

Pilot Fuel Manifold and Injectors

- Manifold to supply fuel to the pilot injectors

- Pilot injectors (three injectors mounted on the combustorhousing).



INLET GUIDEVANE

HIGHPRESSURE

PRESSUREREGULATOR







ACTUATORFILTERPRESSUREPUMP

SERVOVALVE

FLOWDIVIDER

PILOT FUELMANIFOLD

AND

INJECTORS

PURGE TOEXHAUST

LOW FUELPRESSURESWITCH

MAIN FUELMANIFOLD

ANDINJECTORS

3 WAYSOLENOIDVALVE

LOW PRESSUREPUMP

DRAIN

FUELINLET

FUEL SUPPLY

UN-MTERED FUELMETERED FUELFUEL RETURNFUEL DRAIN

CONSTANTDELTA-P VALVE a320-497a

FUEL SYSTEM - OPERATION (1)Starting

When APU start is selected: During starting, the fuel flow is controlled by the servo valve usingsignals from the ECB






- The starter motor is energized and cranks the APU rotor assembly

- The ignition exciter operates and supplies high voltage spark to thetwo igniter plugs

- The 3 way solenoid valve is energized open to provide fuel flow tothe injectors

- The servo valve is electrically operated to control the fuel flow.

Fuel from the aircraft fuel system is supplied by the low pressure andhigh pressure pumps through the servo valve and the 3 way solenoidvalve.

When the fuel pressure reaches approximately 138 kPad (20 PSID),the flow divider delivers fuel to the pilot injectors. The fuel injectedinto the combustor is ignited by the ignitor plugs.

When the fuel pressure reaches approximately 1380 kPad (200PSID), the flow divider delivers fuel to the main injectors.

signals from the ECB.

At self-sustaining speed, the starter and the ignition system aredeactivated and the APU accelerates to 100% speed.

The APU is maintained at 100% speed under all load conditions bythe servo valve controlling fuel flow.






FUEL SYSTEM - OPERATION (1)

STARTING

IGNITION EXCITER ANDIGNITERS OPERATION

TO PILOT INJECTORS

TO MAIN INJECTORS

BY SERVO VALVECONTROLLED BY ECB

FUEL SUPPLY

UN-METERED FUELMETERED FUELFUEL RETURNFUEL DRAIN

a320-498 a

STARTING

FUEL SYSTEM - OPERATION (2)Running Condition

- Stabilized condition

Shut-down

When APU shut-down is initiated (manual or automatic), the ECB de-energizes the 3 way solenoid valve. Fuel flow to the fuel injectors is






The fuel control unit provides a flow higher than APU fuel flowrequirements. The fuel is metered by the servo valve and iscontrolled by the ECB. The excess fuel is returned to the HP pumpinlet through the constant AP valve and the fuel filter.

- Transient condition

When the load applied to the power section changes, the rotationspeed changes. The ECB senses the change and implements asignal to the servo valve. The fuel flow is metered to keep the rotorspeed constant.

g y jshut off and bypassed back into the fuel system.

One second later the ECB de-energizes the fuel servo valve.

Any fuel remaining in the pilot manifold assembly and fuel injectors ispurged into the exhaust by combustor air pressure.




FUELSUPPLYUN-METERED FUELMETERED FUELFUEL RETURN

FUEL DRAIN

a320-499a




FUEL CONTROL UNIT - GENERAL

Function

The fuel control unit (FCU) supplies and meters fuel to the APU.

Main Components

- Fuel pumps






( ) pp

The fuel control unit also supplies regulated fuel pressure to the inletguide vane and bleed control valve actuators.

Location

The fuel control unit is mounted on the front face of the gearbox by av-band clamp.

Interfaces

- Aircraft fuel system

- Pneumatic system actuators

- Drain system

- Control system.

Main Features

- Fuel supply by a low pressure pump and a high pressure pump

- Fuel filtering for the high pressure pump.

- Fuel metering by an electronic system (servo valve and electroniccontrol box).

p p

- Filter

- Servo valve

- 3 way solenoid valve

- Pressure regulator.




FUEL FILTER




SERVO VALVE

FUEL SUPPLYREGULATED FUELMETERED FUELFUEL RETURNFUEL DRAIN

a320-500A

FUEL CONTROL UNIT - DESCRIPTION (1)

Components of the Fuel Control Unit

- A low fuel pressure switch located at the FCU fuel inlet (not)

- A pressure regulator that provides a constant pressure to the air






shown)

- Fuel Pumps

• A low pressure pump (centrifugal type)

• A high pressure pump (gear type) provided with apressure relief valve

- A drain line for the pump shaft seal

- A filter which includes a filter element, a by-pass valve and animpending blockage AP indicator

- A servo valve (electrically operated valve that meters fuel flow inresponse to signals from the electronic control box)

- A constant P valve (a valve that controls the differential pressureacross the servo valve)

- A 3 way solenoid valve (valve operated by the electronic controlbox to open and close fuel flow to the fuel injectors)

system actuators:

• A fuel outlet port (fuel supply to the actuators)

• A fuel return port (fuel return from the actuators)

- A fuel inlet union (connected to the aircraft fuel system)

- An electrical connector (current signals from the electroniccontrol box to the 3 way solenoid valve and the servo valve).

O-rings

Two O-rings are located on the fuel control. One on the fuel controlmounting flange and one on the drive shaft. Both O-rings must beproperly installed or excessive loss of oil will occur when the APU isoperating.




a320-501a





Low Pressure Fuel Pump

The low pressure fuel pump provides a positive supply to the inlet ofthe high pressure pump

High Pressure Fuel Pump

The high pressure fuel pump supplies a fuel flow higher than theAPU requirements The excess fuel is returned to the pump inlet






the high pressure pump.

The pump is mechanically driven at the same speed as the highpressure pump by a splined shaft (driven by the gearbox).

The splined shaft is provided with a seal and a drain line to the drainsystem.

Main Features

- Type: centrifugal

- Rotation speed: 10129 RPM

- Pressure: 550 - 690 kPad (80 - 100 PSID)

- Flow: 182 kg/h (400 lbs/hr) at 550 kPad (80 PSID).

APU requirements. The excess fuel is returned to the pump inlet

through the constant ΔP valve. The pump is also provided with apressure relief valve.

Main Features

- Type: gear type



- Flow: 727 kg/h (1600 lbs/hr)

- Relief valve setting: > 4480 kPad (> 650 PSID).

Note: - Fuel flow at 7 % N: 20 kg/h (45 lbs/hr)- Fuel pressure at 7 % N: 1379 kPad (200 PSID).




FUEL SUPPLYUN-METERED FUEL

METERED FUELFUEL RETURNFUEL DRAIN

a320-502a





Fuel Filter

The filter is located at the outlet of the low pressure pump.






The filter includes the following components:

- A filter element to filter the fuel

Filter specification: 10 microns

- An impending blockage P indicator to provide a visual warningof a restricted filter

Setting: 48 kPad (7 PSID)

- A by-pass valve to allow the fuel supply in the event of filter

blockage

Setting: 324 kPad (46 + - 4 PSID).

O-ring

An O-ring is located inside the fuel filter cavity of the fuel control unit.The O-ring functions as a seal and a securing device for the filterbowel. The bowel is not secured by any external locking device.




FUEL SUPPLY

UN-METERED FUELMETERED FUELFUEL RETURN

a320-503a





Servo Valve

The servo valve meters the fuel during starting and normal operatingconditions.

3 Way Soleno id Valve

The valve opens and closes the fuel supply for operation and shutdown of the APU.






The valve consists of a torque motor which operates a fuel meteringvalve (clevis type).

The motor is electrically controlled by the ECB. ECB currentoperates the valve to meter fuel flow.

During starting, the servo valve meters fuel flow to accelerate the APU.

In normal operating conditions, the fuel flow is metered to maintain aconstant 100% speed.

The main features of the servo valve are:

- Type: Torque motor

- Current: 0 - 100 mA

- Metered flow: 6 - 198 kg/h (13 - 435 lbs/hr).

The solenoid valve is energized open to supply fuel to the fuelinjectors (control from ECB).

When de-energized, a spring moves the valve to the close position.

When the valve closes, the fuel is shut off to the injectors andbypassed back into the fuel system.

During a normal or auto shutdown of the APU the ECB de-energizesthe 3 way solenoid valve, one second later the servo valve is de-energized.

In the event the 3 way solenoid valve does not close, the APU willshut down when the servo valve is de-energized. If this conditionoccurs, the ECB will store a fault message. (APU FUEL VALVEFAILED OPEN).




UN-METERED FUELMETERED FUEL a320-504a





Constant P Valve

The valve maintains a constant pressure differential across the servovalve.

Pressure Regulator

The pressure regulator provides the fuel pressure supply to the inletguide vane actuator and the bleed control valve actuator. The valvei dj t bl






The valve senses upstream pressure on one side and downstreampressure plus the force of a spring on the other side. The valve

position determines the amount of fuel to be returned to the fuelsystem.

The ΔP setting of the constant ΔP valve is of 689 kPad (100 PSID)across the servo valve. The valve is non-adjustable.

is non adjustable.

The pressure regulator is closed from 0 to 60% APU speed. When

the speed is above 60%, the regulator will open and deliver 1724KPad (250 PSID) of fuel pressure to the actuators.




REGULATEDPRESSURE TO

ACTUATORS

REFERENCEPRESSURE FROMLOW PRESSURE

PUMP OUTLET

FUEL RETURNTO LOWPRESSURE

PUMP INLET

PRESSUREFROM HIGHPRESSURE PUMP

FUEL SUPPLYUN-METERED FUELMETERED FUELFUEL RETURN

a320-505a




FLOW DIVIDER - GENERAL

Function

The flow divider distributes fuel from the fuel control unit to the pilotand main injectors. It also provides purging of the pilot injectorsduring APU shut down

Interfaces

- Fuel control unit

Main injector manifold





during APU shut-down.

Location

The flow divider is installed on the left side of the combustor housing.

The flow divider is located downstream of the 3 way solenoid valve.

Main Components

The flow divider consists of two valves:

- A pilot injector and purge valve set at approximately 138 kPad (20PSID) to open.

- A main injector valve set at approximately 1380 kPad (200 PSID)to open.

- Main injector manifold

- Pilot injector manifold

- Exhaust system (purge).

FUELCONTROLUNIT






UN-METERED FUELMETERED FUELFUEL RETURNFUEL PURGE

a320-506a

FLOW DIVIDER - DESCRIPTION AND OPERATION

Description

The flow divider consists of:

- Two valves:

Operating

- Starting

When the APU is started, the fuel pressure increases to 138 kPad





Two valves:

• A pilot injector and purge valve set at approx. 138 kPad

(20 PSID)

• A main injector valve set at approx. 1380 kPad (200 PSID)

- A filter screen (located at the fuel inlet)

- Fuel inlet/outlet ports:

• Fuel inlet from the fuel control unit

• Fuel outlet to the pilot manifold

• Fuel outlet to the main manifold

• Fuel outlet to the exhaust system (purge).

When the APU is started, the fuel pressure increases to 138 kPad(20 PSID). The pilot injector valve opens and allows fuel flow to thepilot injectors.

When the pressure reaches 1380 kPad (200 PSID), the maininjector valve opens allowing fuel flow to the main injectors.

- Normal Running Condition

The two valves remain open to allow fuel flow to the pilot injectorsand the main injectors.

- Shut-down

As the fuel pressure decreases, the two valves close. The fuelremaining in the pilot injectors is purged into the exhaust bycombustor air pressure. At this time, a momentary puff of smokemay be viewed coming from the APU exhaust. This is a normaloccurrence.






METERED FUELFUEL PURGE

PILOT FUEL MANIFOLD AND INJECTORS

Function

The pilot manifold delivers fuel from the flow divider to the pilotinjectors during start and normal operation.





It also supplies the pilot fuel injectors with fuel during normal running.

Location

The pilot manifold is mounted around the combustor housing.

Description

The pilot manifold consists of flexible pipes connecting the flowdivider to the three pilot injectors. It is comprised of teflon tubesencased in a single layer of steel braid that is covered with a rubber

sheath.




FUEL SUPPLYUN METERED FUELMETERED FUELFUEL RETURN

a320-508a



PILOT FUEL INJECTORS

Type

Simple jet injectors.

Location

Description

A simple jet injector comprises:

- A pilot injector body and mounting flange





The three pilot injectors are installed on the rear of the combustor

housing:

- One at the top (at 12 o'clock)

- Two at the bottom (one at 4 o'clock and one at 8 o'clock)

- A fuel nozzle

- A heat shield

The injector fits into a heat shield that is provided with two air inletholes for cooling.

A gasket between the injector and the combustor housing.

Operation

A continuous flow of fuel is delivered to the combustor by the pilotinjectors and atomized by the fuel nozzles, the fuel is then mixedwith combustor air to maintain the combustion process.

METERED FUELINLET






COMBUSTOR HOUSINGREAR FACE

GASKET

PILOT FUELINJECTOR

a320-509aMETERED FUELCOMBUSTOR AIRCOMBUSTION

MAIN FUEL MANIFOLD AND INJECTORS

Function

The main manifold delivers fuel from the flow divider to the maininjectors.

Location





Location

The main manifold is mounted around the combustor housing.

Description

The main manifold consists of flexible pipes connecting the flowdivider to the six main injectors. It is comprised of teflon tubesencased in a single layer of steel braid that is covered with a rubbersheath.




FUEL SUPPLYREGULATED FUELMETERED FUELFUEL RETURN

a320-510a



MAIN FUEL INJECTORS

Type

Air blast injectors.

Location

Operation

A continuous flow of fuel is delivered to the combustor by the maininjectors. The fuel is atomized by combustor air flowing through theshrouded air passage. The fuel is then mixed with combustor air tomaintain the combustion process.





The six main injectors are located on the combustor housing.

Description

An air blast injector comprises:

- A main injector body and mounting flange

- A fuel injection tube and a shrouded air passage

- A gasket between the injector and the combustor housing.

p

MAIN INJJECTOR

BODY





MAIN FUEL INJECTORS

FUEL INJECTOR

TUBE

GASKET

COMBUSTION SWIRL FLOW

METERED FUELCOMBUSTOR AIRCOMBUSTION

a320-511a

FUEL PIPES

Fuel supp ly

- From the aircraft fuel system to the fuel control unit.

Fuel distribution (pipes located on the APU left side)

Fuel drain (pipe located on the APU left side)

- From the flow divider to the exhaust system.

Fuel drain (pipes located on the APU right side)





- From the fuel control unit to the flow divider

- From the fuel flow divider to:

• The pilot manifold and injectors

• The main manifold and injectors

Fuel distribution (pipes located on the APU right side)

- From the pressure regulator of the fuel control unit to:

• The BCV servo valve (fuel supply and return)

• The IGV servo valve (fuel supply and return).

- From the fuel control unit to the APU drain collector

- From the BCV actuator seals to the APU drain collector

- From the IGV actuator seals to the APU drain collector

- From the combustor housing, air bypass plenum and exhaust pipeto the APU drain collector.





FUEL PIPES

FUEL FLOW

DIVIDER

FUEL SUPPLYMETERED FUELFUEL DRAIN

FUEL SYSTEM INTERFACES

The APU fuel system has several interfaces: aircraft fuel system,pneumatic fuel system, APU control system, APU drain system.

Aircraf t Fuel Sys tem

The APU is supplied with fuel normally from the aircraft left wingtank The aircraft low pressure fuel pump provides fuel to the APU





tank. The aircraft low pressure fuel pump provides fuel to the APU

when the aircraft tank pumps are not operating.

The low pressure valve is controlled by the ECB and is open whenthe APU is operating. The valve is closed when the APU is shutdown normally or by the APU fire switch.




FUEL SUPPLY

REGULATED FUELFUEL DRAIN

a320-513a



AIRCRAFT FUEL SYSTEM

The aircraft fuel system supplies fuel to the main engines and APU.

The aircraft fuel system has three main tanks:

- A left tank located inside the left wing

- A center tank located between the two wings

A low fuel pressure warning switch is located at the fuel inlet to thefuel inlet to the fuel control unit. The switch sends a signal to theECB if fuel pressure is too low.

The ECB will display "FUEL LO PR" message on the lower ECAMwhen the APU system page is selected. This requires the APU to beabove 7% speed and the fuel pressure below 109 KPag (15 8 PSIG)






- A right tank located inside the right wing.

Each tank has electric pumps to supply the engines.

A cross feed valve, located between the tanks, connects the leftand right engine supply lines. In normal operation, the cross feedvalve is closed.

The low pressure valve isolates the APU from the fuel supply.

The valve is open when the APU is running. It closes when the APUis shutdown or when the FIRE switch is activated.

The APU low pressure fuel pump is controlled by a pressure switchlocated in the fuel line to the APU. The switch senses fuel tank pumppressure. If the pressure is too low or the fuel tank pumps are turnedoff, the switch will cause the APU low pressure fuel pump to turn on.

above 7% speed and the fuel pressure below 109 KPag (15.8 PSIG).




APU LOW PRESSURE

FUEL PUMP

a320-514a

LOW FUEL PRESSURE

WARNING SWITCH






APS 32OO AUXILIARY POWER UNIT


.

APS 3200AUXILIARY POWER UNIT




AUXILIARY POWER UNIT

SECTION 5

AIR SYSTEM


AIR SYSTEM - GENERAL

Function

The air system provides compressed air to the aircraft on the groundand in flight.

Main Features

Component Location

The inlet guide vane system components are located on the rightupper side of the air inlet housing. The inlet guide vanes arelocated in the air inlet housing ahead of the load compressor air inlet.

The air bleed system components are located on the right lowerside of the load compressor scroll outlet





- Flow: 1.2 kg/s (2.6 lbs/sec.)

- Pressure: 289.6 kPag (42 PSIG)

- Temperature: 232°C (450°F).

Main Components

Two systems are considered:

- The inlet guide vane (IGV) system controls the load compressorairflow and prevents EGT overtemperature of the power sectionduring load compressor operation. The inlet guide vanes arecontrolled by the ECB, servo valve, and the IGV actuator.

- The air bleed system delivers airflow from the load compressor tothe aircraft pneumatic system through a bleed control valve (BCV).The valve also functions as an anti-surge valve for the loadcompressor. The BCV is controlled by the ECB, servo valve, and

the BCV actuator.

side of the load compressor scroll outlet.

All the sensors are located on the APU.

Interfaces

- The ECB

- The aircraft pneumatic system


.






AMBIENT AIRCOMPRESSED AIRREGULATED FUELFUEL RETURN

AIR SYSTEM - OPERATION

Control of the System

The ECB uses various control signals from the aircraft and the APUsensors to control the inlet guide vanes and the bleed control valve.

Indication





The pressure is indicated on the lower ECAM APU system pagedisplay. The pressure is indicated by the load compressor dischargepressure sensor and transmitted to the indicator through the ECB,the ADIRU, the BMC computers in PSIG.

Air Sys tem Operation

The air system operation chart shows IGV and positions duringvarious modes of operation

.

ENGINE BLEED PACK MODE AIRCRAFT IGV BCVSPEED SWITCH MODEL POSITION POSITION

%




0 - ALL CLOSED DISCHARGE72º ( 0)

100 OFF CLOSED - ALL CLOSED DISCHARGE82º ( 0)

100 ON OPEN - ALL OPEN DELIVERY 48º 45º TO 90º

100 ON OPEN ECS A318 OPEN DELIVERY A319 48º TO -30º 90º

A320

100 ON OPEN ECS A321 OPEN DELIVERY48º TO -10º 90º

100 ON CLOSED MES ALL OPEN DELIVERY

-5º 90º

OPERATION CHART



INLET GUIDE VANE SYSTEM - GENERAL

Function

The inlet guide vane system controls the load compressor air flow toprovide the required flow to the aircraft pneumatic systems.

Main Features

Interfaces-Fuel inlet (fuel pressure)

Fuel outlet (fuel return)

- Fuel drain





- Hydraulically operated actuator, controlled by a servo-valve andthe electronic control box.

Components Involved

- The electronic control box (ECB)

- The inlet guide vane (IGV) system components: servo valve,actuator, control mechanism and inlet guide vanes

Components Location

- The servo-valve and actuator form an assembly located on theright upper part of the APU on the air inlet housing.

- The inlet guide vanes and their control mechanism are located inthe air inlet housing.

- Control signal from the ECB to the servo valve

- Position signal from the LVDT (Linear Voltage DifferentialTransducer) to the ECB

- EGT signal from APU exhaust thermocouples to the ECB.




REGULATED FUELFUEL RETURNFUEL DRAIN



INLET GUIDE VANE SYSTEM - DESCRIPTION (1)

The system includes the actuator, the control rod and the IGVmechanism.

IGV Actuator

Hydraulically operated actuator using fuel supplied by the FCU, itcomprises of a servo valve and an operating piston.





Control Rod

The rod connects the actuator piston to the IGV assembly. It isconnected to the actuator piston by a quick release pin.

IGV Position Indicator

The actuator rod housing has a position indicator cast on the top andbottom of the housing. The indicator markings range from CLOSEDto OPEN. An external metal tab is attached to the control rod andfunctions as a position indicator for the IGV’s and used to manuallymove the IGV’s when the APU is not running. The igv’s should be inthe CLOSED position before starting the APU.

IGV POSITION

INDICATOROPEN

ACTUATOR

CLOSED




ACTUATOR

ROD HOUSING

METAL TAB

a 320-516.1




Servo Valve

The servo valve controls the position of the actuator piston by usinga spill valve that meters the potentiometric jet. The servo valve has ametered fuel pressure inlet from the actuator and a return outlet tothe fuel control unit. The control current (0-100 MA) to the servovalve is provided by the ECB.

A t t

IGV Contro l Mechanism and Inlet Guide Vanes

The inlet guide vanes are part of the IGV assembly. A sector gear isattached to each inlet guide vane and is driven by a common ringgear.





Actuator

The actuator consists of a piston that is positioned by fuel pressuremetered by the servo valve. The actuator also uses double dynamicseals for piston shaft sealing.

The position of the actuator piston is provided by a Linear VoltageDifferential Transducer (LVDT). The position signal is sent to theECB for control of the servo valve.




METRED

FUEL PRESSURE

FUEL PRESSUREMETERED FUEL PRESSUREFUEL RETURNFUEL DRAIN



INLET GUIDE VANE SYSTEM - OPERATION

Principle of Operation

The ECB provides a control signal (0-100 MA) to the servo valve byusing the following input signals.

- APU bleed switch

- Speed (100%)

APU Star ting

During start, the inlet guide vanes are in the closed position toreduce the APU starting loads. The inlet guide vanes are also in theclosed position during APU shutdown.

Operation

During load compressor operation the position of the guide vanes





- EGT

- Air inlet pressure and temperature

- ECS mode

- MES mode.

The ECB control signal is sent to the servo valve. The servo valvemeters fuel pressure to control the actuator piston movement.

When the actuator moves, the linear voltage differential transducer(LVDT) sends the actuator position signal back to the ECB.

The actuator piston is maintained in a stabilized position by the ECBsignal (50 MA) to the servo valve.

The actuator piston positions the IGV assembly to control the airflowdelivery of the load compressor.

During load compressor operation, the position of the guide vanesare controlled by aircraft ECS computer signals sent to the ECB.

In the event APU exhaust gas temperature is too high during loadcompressor operation the ECB will signal the IGV actuator to reduceairflow delivery of the load compressor.

If inlet guide vane control is faulty, the IGV actuator will automaticallyposition the guide vanes to the closed position.

.

AIR INLETPRESSURE ANDTEMPERATURE




NOTE:

SEE OPERATIONCHART PAGE 5.4 FOR

AIRCRAFT MODEL

AND IGV POSITIONS

FUEL PRESSUREMETERED FUEL PRESSURE

FUEL RETURNFUEL DRAIN



AIR BLEED SYSTEM - GENERALFunction

The air bleed system provides air delivery to the aircraft pneumaticsystem while preventing load compressor surge.

Main Features


Component Location

- The servo-valve, the actuator and the bleed control valve form acomplete assembly located on the right lower part of the auxiliarypower unit at the scroll outlet

- Two load compressor discharge pressure pipes:

• One located in the scroll outlet (high pressure)





Components Involved


- The Bleed Control Valve (BCV): servo-valve, actuator and valve

- Pressure sensors

- Ducts.

• One located in the diffuser of the load compressor (lowpressure)

Both are connected to the load compressor dischargepressure sensor to prevent load compressor surge.

Interfaces

- Fuel inlet

- Fuel outlet

- Fuel drain


- Position signal from the LVDT to the ECB

- Pressure signals to the load compressor discharge pressuresensor.




REGULATED FUELRETURN FUELFUEL DRAIN

AIR BLEED SYSTEM - GENERAL


AIR BLEED SYSTEM - DESCRIPTION (1)

The air bleed supply is controlled by a bleed control valve.

This valve comprises of a housing, a butterfly valve and an actuator.

APU Bleed Switch

When the APU master switch is selected to off during bleed airoperation, the APU will continue to run in a cool down mode for amaximum time of 2 minutes.

APU Bleed Switch


The cooldown time limit can vary from 0 to 2 minutes. The time limitdepends on when the APU bleed switch is turned off prior toselecting the APU master switch to OFF.





Housing

The housing is mounted on the load compressor scroll outlet bymeans of a v-band clamp.

Butterfly Valve

The valve is located in the BCV housing and directs air flow from theload compressor to the aircraft pneumatic systems, APU exhaust orboth.

The butterfly shaft extends through the top of the BCV housing. Theshaft has a slot machined into it that provides manual positioning ofthe valve and also serves as a valve position indicator.

Low B leed Air Pressure

In the event low bleed air pressure occurs, cycle the APU bleedswitch OFF and then to ON. This may restore the system to normal.







Servo Valve

The servo valve controls the position of the actuator piston by usinga spill valve that meters the potentiometric jet. The servo valve has ametered fuel pressure inlet from the actuator and a return outlet tothe fuel control unit. The control current (0-100 MA) to the servovalve is provided by the ECB.

Actuator

Bleed Control Valve

The bleed control valve (BCV) delivers compressed air to the aircraft,also the valve functions as an anti-surge valve for the loadcompressor.






The position of the actuator piston is provided by a linear voltagedifferential transducer (LVDT). The position signal is sent to the ECBfor control of the servo valve.




COMPRESSED AIRREGULATED FUELMETERED FUELFUEL RETURNFUEL DRAIN



AIR BLEED SYSTEM - OPERATION


The ECB provides a control signal (0-100 MA) to the servo valveusing the following inputs:

- APU bleed switch

- Speed (100%)

Air inlet temperature

APU Star ting

During start and shutdown the BCV is in the discharge position.

If the valve control is faulty, the BCV actuator will automaticallyposition the valve to discharge.





- Air inlet temperature

- Load compressor discharge pressure sensor (ΔP/P).


When the actuator piston moves, the linear voltage differential

transducer (LVDT) sends the actuator position signal back to theECB.


The actuator piston positions the BCV to deliver the maximum airflowto the aircraft pneumatic systems without causing load compressorsurge.







AIR SYSTEM SENSORS - INLET AIR PRESSURE AND TEMPERATURE SENSOR

Function

The air inlet pressure and temperature signals are used by the ECBfor control purposes.

Location

The pressure and temperature sensors are in one unit which is

located on the right rear side of the air inlet plenum.

- Supply current: 1 mA

- Range: -55 to +150°C (-62 to 302°F)

- Resistance at 0°C (0°F): 1000 Ω.


- The pressure sensor is made of a bridge of 4 resistors printed ona flexible support One of them varies if the support is deformed by




Main Features

Pressure Sensor

- Type: variable resistor device

- Excitation voltage: + 5 and - 5 VDC

- Output signal: 0 to 50 mV

- Range: 0 to 104 kPaa (0 to 15 PSIA)

- Minimum bridge impedance: 2000Ω.

Temperature Sensor

- Type: resistance temperature device

a flexible support. One of them varies if the support is deformed bythe air pressure. The whole bridge is supplied by a 5 VDC constantsource voltage coming from the ECB. The changes of the variableresistor cause the output to vary (from 0 to 50 mV).

- The temperature sensor is a resistor which is fed by a constant 1mA current supplied by the ECB. The output voltage changes fromapproximately 0.8 to 1.2 VDC according to the resistance changes

from -55 to +50°C (-67 to +122°F).

The ECB detects a sensor failure if:

- The measured ambient pressure is lower than 3.45 kPaa(0.5 PSIA) or higher than 110 kPaa (16 PSIA)

- The measured inlet temperature is lower than -62°C (-80°F) orhigher than 76°C (170°F)

Normal BCV control will be maintained if either air inlet pressure ortemperature sensor is failed.





AIR SYSTEM SENSORS


AIR SYSTEM SENSORS - LOAD COMPRESSOR DISCHARGE PRESSURE SENSORS

General

Function

The load compressor discharge pressure sensors sense loadcompressor air pressure (high pressure) and (low pressure).

The ECB receives signals from the sensors and adjusts the bleed

control valve (BCV) to prevent load compressor surge.

Description

The two sensors are made of a bridge of 4 resistors.

The resistors are printed on a flexible support and one of them variesif the support is deformed by the pressure.

The bridges are supplied by a constant source voltage of 5 VDC

coming from the ECB.





Location

The pressure sensors (ΔP/P) are assembled as one unit. Thesensors are located on the right front side of the air inlet plenum.

Main Features

The pressure sensors are variable resistor devices.

Excitation voltage: + 5 and - 5 VDC

Output signal: 0 to 50 mV

Range 0 to 172 kPad (0 to 25 PSID) (ΔP)0 to 689 kPaa (0 to 100 PSIA) (P)

Minimum bridge impedance: 2000 Ω.

The changes of the variable resistor causes the output voltage tovary (from 0 to 50 millivolt).


- The measured pressure is lower than 3.45 kPad (0.5 PSID) orhigher than 172 kPa (25 PSI) or than 690 kPa (100 PSI)

The load compressor bleed air pressure is displayed on the lowerECAM when the APU system page is selected.




LOAD COMPRESSOR DISCHARGE PRESSURE SENSORS

AIR SYSTEM SENSORS


ACCESSORY COOLING - GENERAL

Function

The accessory cooling system supplies air for the oil cooler and forthe APU compartment ventilation.

Location

The system components are located on the APU.

Main Features

Cooling Fan

The fan provides cooling air to the oil cooler and to the compartmentcooling duct. The fan assembly incorporates a permanent magnetgenerator that is used for APU backup overspeed and to preventmomentary power interruption of the ECB.

Fan Outlet Duct

This duct connects the outlet of the cooling fan to the inlet of the oilcooler





Cooling by circulation of air taken from the air inlet plenum andaccelerated by the cooling fan.

Main Components

The main components of the system are the fan inlet duct assembly,

the cooling fan, the fan outlet duct assembly, the oil cooler and theoil cooler exhaust duct.

Fan Inlet Duct

This duct connects the engine air inlet plenum to the inlet of thecooling fan.

cooler.

Oil Cooler Exhaust Duct

This duct connects the oil cooler outlet to the APU compartment doorvent.

Compartment Cooling

The APU compartment is ventilated by air ducted from the coolingfan outlet duct. The air is discharged into the compartment throughthe compartment cooling duct.






ACCESSORY COOLING - COOLING FAN

General

Function

The cooling fan (driven by the gearbox) provides air circulation forthe oil cooler and ventilation of the APU compartment.

The cooling fan incorporates a permanent magnet generator that

provides momentary direct current power, and a backup overspeedsignal to the electronic control box.

Main Components

- The cooling fan assembly includes:

• An axial flow fan

• The fan drive gear

• 2 roller bearings

- Fan inlet and outlet ducts





Location

The cooling fan is located at the top of the gearbox front face and issecured by a V-band clamp.

Main Features

- Cooling fan rotation speed: 51965 RPM

- Permanent Magnet Generator output: 40 VDC (100% of N)

- Speed signal for back-up of the overspeed protection system:107%.


- A permanent magnet generator and control box.




COOLING FAN - GENERAL

ACCESSORY COOLING



Description

The cooling fan is mounted on the gearbox and aligned by a locatingpin. The fan mounting flange is secured to the gearbox by a v-bandclamp.

The fan is driven by a shaft assembly that is supported by two ballbearings, the bearings are lubricated by the APU oil system. The

shaft assembly uses a carbon seal and two labyrinth sealspressurized by the power section impeller air. The oil used forlubrication of the cooling fan is returned to the oil sump by gravity.

Operation

Cooling Fan

The cooling fan accelerates the air flow through the oil cooler.Cooling air is also used for APU compartment cooling.

PMG

The permanent magnet generator (PMG) is driven by the cooling fanshaft. The PMG provides momentary (240 msec) of rectified





g p y g y

A permanent magnet generator (PMG) and a printed circuit boardare located in the fan housing. The printed circuit board contains therectifier components for the PMG electrical power output to the ECB.

The cooling fan can be used to turn the APU rotor assembly during

borescoping. This is accomplished by removing the fan inlet duct andmanually rotate the fan impeller.

p y ( )electrical power to the ECB when the aircraft electrical power isinterrupted during power transfer.

One unrectified PMG output provides a frequency signal to the ECBthat is used for the back up overspeed signal.




AMBIENT AIROIL SUPPLYOIL DRAINPRESSURIZED AIR

COOLING FAN - DESCRIPTION AND OPERATION

ACCESSORY COOLING


AIRCRAFT PNEUMATIC SYSTEM

The aircraft pneumatic system supplies compressed air to thefollowing:

- Aircraft air conditioning system

- Water tank pressurization

- Aft cargo heating

- Wing anti-icing system





- Main engine starting system

- Hydraulic reservoir pressurization.

The compressed air , used by the aircraft pneumatic system, can besupplied by:

- The APU

- Number 1 engine

- Number 2 engine

- Ground air source.

ENG. 1BLEED

HOT AIR

PACK 1ENG 2BLEED

PACK 2

X BLEED

GROUND AIR

APUBLEEDVALVE(BCV)






APU COMPRESSED AIRENGINE FAN COOLING AIR

FAULT LIGHTOFF LIGHT

SUPPLY(BCV)









HSPS CT/NOV.. 2006 Page 6.0HAMILTON STANDARD PROPRIETARY

SECTION 6

CONTROL SYSTEM


APU CONTROL SYSTEM - GENERAL

Functions

The functions of the APU Control System are:

- To keep the power unit rotation speed constant to maintain ACgenerator frequency

- To protect the power unit from overtemperature

- To avoid load compressor surge

- To ensure a proper start of the power unit

Main Components

The main components of the APU control system are:

- The APU components (sensors, pressure switches, servo-valve,actuators ...)

- The electronic control box

- The aircraft control panels.






- To provide a proper start sequence.

- To monitor APU component operation.

- To supply fault information for trouble shooting, engine trendmonitoring and historical data retention.

Main Features

- FADEC (Full Authority Digital Electronic Controller)

- Single computer

- Electrical supply from the aircraft DC system and momentarypower backup from the cooling fan PMG.






APU CONTROL SYSTEM - DESCRIPTION (1)

General

This description considers:


- The ECB inputs

- The ECB outputs

- The ECB supply

ECB Outputs

They are the accessories (electro-valves, relays...) and indicatingdevices.

ECB Electrical Supply

- 28 VDC supply: from the aircraft electrical system

- Momentary supply: from the permanent magnet generator (part ofthe cooling fan assembly).





- The electrical harness.

ECB

The ECB is located in the aft cargo compartment.

The unit is made of six printed wiring assemblies using digitaltechnology components.

ECB Inputs

They are the sensors (rotation speed, temperature, pressure...) anddiscrete signals (microswitches and switches).

Electrical Harness

The APU harness connects the APU to the aircraft electrical system.







Control System Components

Components of the control system:


- Oil filter switch indicators


- Oil level sensor

- Inlet guide vane servo valve

- Bleed control valve servo valve

- Fuel servo valve


- Low fuel pressure switch

- Permanent magnet generator





- De-oiling valve

- Speed sensors

- EGT sensors

- Inlet air pressure sensor

- Inlet air temperature sensor

- Load compressor discharge pressure sensor

- Linear voltage differential transducers (LVDTs)

- Engine identification module

- Exciter

- Starter voltage sensing

- Centralized Fault Display System (CFDS)

- Aircraft discrete inputs and outputs.





CONTROL SYSTEM COMPONENTS


APU CONTROL SYSTEM - OPERATION (1)

Rotation Speed Contro l

General

This function meters the fuel flow to maintain a constant rotor speed.

Components Involved

- Speed sensors

- Electronic Control Box (ECB)

Fuel servo valve

Exhaust Gas Temperature (EGT) Control

General

This function protects the power unit against over-temperature.

Components Involved

- EGT thermocouples, the speed sensors and the inlet pressure andtemperature signals

- ECB





- Fuel servo-valve.


The ECB compares rotor speed with a nominal speed datum to

control the fuel servo-valve. The servo-valve then provides therequired fuel flow to maintain 100% rotor speed under all APU loadconditions.

- IGV actuator.


The ECB compares the actual EGT with an EGT datum.

The EGT datum is a function of the operating mode (ECS or MES)and of the ambient air conditions (P1 and T1).

The ECB controls the IGV servo-valve as a function of EGT.

The IGV's are modulated toward close as EGT exceeds the datum.




FUEL SUPPLY

UN METERED FUELMETERED FUEL APU CONTROL SYSTEM - OPERATION (1)FUEL RETURN

ROTATION SPEED CONTROL AND EGT CONTROL



Load Compressor Surge Control

General

This function protects the load compressor from surge.

Components Involved

- Load compressor output pressure sensors


- Bleed control valve

Load Compressor Reverse Flow Protection

General

This function shuts down the APU in case of load compressor surge(eg. back pressure from the aircraft pneumatic system).

Components Involved


- ECB





Bleed control valve.


The ECB compares the load compressor delivery pressure ratio

(Δ

P/P) with a datum pressure ratio. In case of a low airflow condition,the bleed control valve is modulated to discharge air into the APUexhaust.

- Fuel system and bleed control valve.


The ECB compares the load compressor delivery pressure ratio withtwo datums:

When the first datum is reached, the bleed control valve (BCV) willmove to the discharge position.

When the second datum is reached, the APU will automaticallyshutdown.




METERED FUEL

APU CONTROL SYSTEM - OPERATION (2)FUEL RETURN

LOAD COMPRESSOR SURGE CONTROL AND REVERSE FLOW PROTECTION



APU Star t Fuel Flow Control

General

This function meters the fuel flow during APU starting.

Components Involved

- Speed sensors, the EGT thermocouples, the air inlet pressure andtemperature probes



The fuel flow program has two phases:

- The first phase: EGT rise

- The second phase: From EGT rise to 95% speed + 2 seconds.

During the first phase, the fuel supply is used to fill the manifold. Fuelflow is metered as a function of rotor speed only.





- Fuel servo-valve. During the second phase, fuel flow is scheduled as a function of twoprograms (automatically selected):

The first program controls the fuel flow rate after comparing theactual acceleration with the acceleration rate datum.

The second program controls the fuel flow rate after comparing theactual EGT with the EGT datum.

CONTROLSYSTEM

ECB




ECB


APU START FUEL FLOW CONTROL




APU Faul t Sys tem

General

The APU is either shut down automatically or a warning is given incase of a fault.

Components

- The sensors

- The ECB

Th l i l i





- The electrical accessories.

Operation

In the event of a fault shutdown of the APU, the supplied electricaland pneumatic loads are removed.

Warning lights, messages and indicators are displayed in the flightdeck.

Fault messages are available through the Centralized Fault DisplaySystem.




Monitoring

Function

The system provides information about the APU actual status,operation and maintenance.

The system displays:

- APU parameters

- Events and hours count

Condition and faults





- Condition and faults.

Components Involved

- APU control system components

- The ECB

- The flight deck indicating system (CFDS, ECAM, MCDU).





MONITORING


ELECTRONIC CONTROL BOX - GENERAL

Function

The Electronic Control Box (ECB) controls and monitors the AuxiliaryPower Unit systems.Location

The ECB is installed in the aft cargo compartment.

Main Features

-Full Authority Digital Electronic Controller (FADEC)- On Board Replaceable Memory Module (OBRM) for design

flexibility and reduced component count- Modular design for reliability, maintainability and testability

Weight and Dimensions

Weight: 7.3 kg (16.1 lbs)Dimensions:Weight and Dimensions

-• Width: 159 mm (6.2 inches)• Height: 195.4 mm (7.6 inches)• Depth: 375.4 mm (14.6 inches).

Main Components

The main components are:- The ECB enclosure which houses Printed Wiring Assemblies

(PWA)- The ECB front face which includes:





- No calibration required- Digital communication links (ARINC 429 and RS 232-C)

• A RS 232-C connector• A front cover door housing the On Board Replaceable

Memory Module (OBRM)• A handle

- The ECB rear face which includes an ARINC 600 connector.

Identification

The electronic control box has an identification plate and amodification plate, both located on the front face of the ECB.






ELECTRONIC CONTROL BOX - DESCRIPTION (1)

ECB Inputs

General

This chapter considers the discrete and analog input signals to theECB.Sensors and Discrete Inputs from Ai rcraft to ECB

The corresponding signals form part of the ECB Inputs-Outputsdefinitions and PIN assignments.

The bleed control valve (BCV) command is transmitted to theECB by means of an aircraft discrete signal. Upon receipt of thiscommand, the ECB contro ls the opening o f the BCV to supplythe aircraft pneumatic sys tem.

Air/ground Conf iguration Switch (open/ground)

This signal to the ECB is to indicate whether or not the aircraft is in-flight operation. Special considerations (i.e. safety systems) apply forin-flight operation.





definitions and PIN assignments.

APU Stop (ground)

The stop signal is transmitted to the ECB by the APU master switchin the flight deck. Actuating the switch causes a contact closure toground.

Bleed Control Valve Activation (ground)

Emergency Stop (ground for approx. 150 ms)

The emergency stop signal is transmitted to the ECB by means of adiscrete signal created by a contact closure to ground.

in flight operation.

MES Mode (28 V)

This signal indicates to the ECB whether or not the aircraft is in MainEngine Start mode (MES) of operation. The circuit is normally open.In the MES mode, the aircraft causes the circuit to close and tosupply a 28 V signal to the ECB.

Start Contactor Monitor (28 VDC/open/ground)

This discrete 28 VDC signal tells the ECB whether or not the back-upstart contactor is closed or whether or not it is open.The start contactor monitor is used exclusively for fault isolation

purposes.





SENSORS AND DISCRETE INPUTS FROM AIRCRAFT TO ECB



Sensors and Discrete Inputs from Aircraft to ECB (continued)

Air Intake Flap Open Posi tion (28 VDC)

When the air intake flap is in the fully open position, a switch isactivated to supply a 28 VDC signal to the ECB.

This signal is used to initiate the start sequence.

JAR Configuration

The ECB is programmed in the JAR mode. This means that allshutdown faults sensed by the ECB will cause the APU to shutdownon the ground or in flight.

Low Fuel Pressure Switch (open/ground)

The switch closes to ground when the fuel pressure falls below agiven pressure.

Air Intake Flap Closed Posit ion (ground)

When the air intake flap is in the fully closed position, a switch isactivated to the closed position and provides a ground signal to theECB. The aircraft relay operation is maintained until the flap closedsignal is received.

Air Intake Flap Movement (28 VDC)

D i l APU ti 28 VDC i l i t itt d t th





Start Command (28 VDC for approx. 150 ms)

This command is activated by momentarily placing the start button in

the flight deck to "on". This action provides a 28 V signal to the ECB.

During normal APU operation, a 28 VDC signal is transmitted to theECB when voltage is being applied to open or close the air intakeflap.

Generator Oil Temperature Sensor (100 )

This sensor is mounted in the AC generator. The wiring uses thegenerator connector, P4. The sensor is a resistance temperaturedevice (RTD). It's variable resistance is a function of temperatureand is supplied with a constant current of 1 mA.








Sensors and Discrete Inputs from APU to ECB

Low Oil Pressure Switch (ground)

The low oil pressure switch is a normally closed contact. The switchopens and remains open when oil pressure is present.

Oil Filter Switch Indicators

This is a differential pressure switch that is normally open. Thecontact closes and provides a ground signal in case of filterrestriction.

EGT Sensors

This sensor is a variable resistance device supplied by a constantsource voltage of 5 VDC.

The output ranges from 0 to 50 mV for a 0 to 15 PSIA range of airpressure.

Load Compressor Discharge Air Pressure Sensors (P) and (

P)

There are two sensors: one to measure the pressure at the loadcompressor scroll (P), the other one to measure the differential airpressure between the diffuser and the scroll (AP). The ratio signal

AP/P is used to prevent load compressor surge.

The two sensors are of variable resistance type supplied by aconstant voltage of 5 VDC





The EGT is measured by two independent thermocouples. They areK type (Chromel-Alumel).

The output is of approx. 1 mV per 24°C (43°F).

High Oil Temperature Sensor (100 )

The sensor is a Resistance Temperature Device (RTD). Theresistance varies according to the oil temperature and is suppliedwith a constant current of 1 mA.

Inlet Air Pressure Sensor

constant voltage of 5 VDC.

The outputs range from 0 to 50 mV for a 0 to 100 PSIA (absolute) or0 to 25 PSID (differential) ranges of air pressure.

Rotation Speed Sensors

There are two independent speed sensors mounted in the gearbox.

They provide a wave signal as a function of the teeth on the phoneticwheel (24) and the rotation speed (i.e. 19720 Hz at 100% speed).




SENSORS AND DISCRETE INPUTS - FROM APU TO ECB




Sensors and Discrete Inputs from APU to ECB (continued)

Inlet Air Temperature Sensor (1000 RTD)

The sensor is a variable resistance temperature device supplied by aconstant source current of 1 mA. Temperature range -55 to 150°C(-67 to 302°F).

Engine ID Module

The engine identification (ID) module is resistors that provide theECB with 3 voltage lines V 1, V2, V3 matched to the engine IDnumber. The engine serial number is the sum of the ID number andthe number 1000.

IGV and Bleed Control Valve LVDTs(Linear Voltage Differential Transducer)

LVDTs are used to detect the actual displacement of the IGV andBCV actuators. Their signal is fed back to the ECB for the purpose ofservo control.

Their primary coil is supplied with a constant voltage of 10 VAC.Their secondary coil provides a variable output voltage.

Upon loss of electrical signal, the IGV will close or the BCV opens todischarge.

Oil Level Sensor (100 A)





The engine ID number is stored in the ECB NOVRAM memory aspart of the power up initialization. The ID module is considered failedwhen all inputs are shorted, one or all inputs are open, a number

greater than 2048 is used, or 3 consecutive readings at power upinitialization are not identical.

The gearbox mounted oil level sensor is a Resistance TemperatureDevice (RTD) type. The variable resistance value is provided with aconstant current of 75 mA. The oil level is checked at power up over

a period of 8 seconds and is determined OK or LOW.




SENSORS AND DISCRETE INPUTS FROM APU TO ECB





Permanent Magnet Generator (PMG)

A Permanent Magnet Generator (PMG) is installed in the cooling fan.The assembly consists of the PMG rectifier circuit and a DC fusiblelink.

The PMG provides the ECB with rectified power and one unrectified

signal from one of the three phases (backup overspeed protection at107%).

The unrectified output is current limited (short circuit protection) bymeans of a resistor. The fusible link trip point is at 10 A.

Starter Motor Voltage

The starter motor is monitored by the ECB for low voltage during APU start. The low voltage sensing connector is located on the frontface of the starter motor housing.





The rectified output provides 40 VDC at 100% speed for back-uppower supply to the ECB in the event of a momentary interruption inthe main power supply. This back-up supply lasts for 240 msec.

Note: The failure of the PMG/Speed circuit at startup will cause the APU to shutdown during acceleration.








ECB Outputs

General

This chapter considers the discrete and digital outputs of the ECB.

Discrete and Digital Outputs (to the aircraft)

Backup Start Contactor (28 VDC, 1 A nominal)

This contactor is energized by means of a discrete signal. The signalis supplied through a Field Effect Transistor (FET) in the ECB.

Main Start Contactor (28 VDC, 1 A nominal)

Thi t t i i d b f di t i l Th i l

Bleed Control Valve Open (28 VDC, 0.1 A)

The ECB transmits a discrete signal to the aircraft indicating systemwhen the bleed control valve is in the position that allows maximumflow to the aircraft pneumatic system.

APU Available (28 VDC, 0.4 A)

The ECB provides a discrete signal to the AVAIL light in the start

switch when the APU has completed the start sequence and is readyto load.

Start in Progress (28 VDC, 0.1 A)

The ECB transmits a discrete signal to the ON light in the start switchto indicate a start is in progress





This contactor is energized by means of a discrete signal. The signalis supplied through a FET device in the ECB.

Aircraf t Relay (ground, 0.4 A)

The aircraft relay is activated by a closed contact to ground throughthe ECB. The aircraft relay is activated when the ECB is energizedand no stop command is present.

to indicate a start is in progress.

The light is "ON" from the beginning of the start until the "APU

available" light turns on.

Fault (28 VDC, 0.2 A)

The ECB transmits a fault discrete signal to the aircraft for allshutdowns.




DISCRETE AND DIGITAL OUTPUTS (TO THE AIRCRAFT)




Discrete and Digital Outputs (to the aircraft) (continued)

Flap Open Command (28 VDC, 3.5 A)

The ECB provides a power output for opening the air intake flap. Theflap open command is emitted through a FET device in the ECB.

This output is protected against overload and short circuits.

Flap Closed Command (28 VDC, 3.5 A)

The ECB provides a power output for closing the air intake flap. Theflap closed command is emitted through a FET device in the ECB.


• ARINC 429 input from ECS: It is used by the ECB toreceive specific data from the Environmental ControlSystem (i.e. ECS demand signal, ECS valve status word,etc...)The ECS demand signal is used in the control of the IGV's.The ECS valve status word informs the ECB of the numberof air conditioning packs currently supplying air

• ARINC 429 CFDS output: The ARINC 429 output

transmits data to the CFDS, ECAM (Electronic Centralized Aircraft Monitoring) and ACMS (Aircraft ConditionMonitoring System)

- One RS 232 C interface: This interface is accessible on the rear ARINC connector and on the front face connector.





Aircraf t Serial Communications

Data communication is achieved by means of four serialcommunication links:

- ARINC 429 CFDS output: Three ARINC 429 serial links (theyoperate at low speed - 12.5 K bits/sec)

• ARINC 429 input f rom CFDS: It is used by the ECB toreceive specific data from the Central Fault DisplaySystem with appropriate ARINC labels

It can be used:

• As a maintenance tool

• To access the test modes of the ECB

• To change the ECB software characteristics duringdevelopment.








Discrete and Analog Outputs (to the APU)

Oil System De-oili ng valve (28 VDC, 1 A)

This output is activated to operate the valve during starting andshutdown.

Exci ter (28 VDC, 2 A)

This output is activated to supply the exciter during starting.

3 Way Solenoid Valve (28 VDC, 1 A)

This output is activated to operate the valve for start and shutdown.

Oil Level RTD, Oil Filter and LOP switches (Rtn, 1 A)

IGV and Bleed Control Valve LVDTs (3000 Hz, 10 VAC)

These two separate outputs supply a reference source signal to eachprimary coil.

IGV, Bleed Control Valve, Fuel Servo (0 - 100 mA)

These three separate outputs supply a variable low intensity signal tothe corresponding servo-valve.





, ( , )

This output is common to all three items.

Pressure Transducers Excitation (5 VDC, 30 mA)

This output is activated to operate the air pressure transducers witha stabilized voltage.




DISCRETE AND DIGITAL OUTPUTS (TO THE APU)




Hardware Description

The Electronic Control Box consists of an enclosure which includesthe following components:

- Six Printed Wiring Assemblies (PWA):

• A speed and temperature PWA

• A discrete input-output PWA

• A microprocessor PWA

• An analog input PWA

• An analog output PWA

- An On Board Replaceable Memory Module (OBRM) accessiblethrough a removable front cover door.

The board is equipped with an UVPROM type memory to be usedas the programme memory space for the ECB.

- Two electrical connectors:

• A RS 232 connector located on the ECB front face

• An ARINC 600 connector located on the ECB rear face.





• A power supply PWA

- One printed wiring assembly for Electromagnetic Interference(EMI) and lightn ing protection

- PWA guides

- A backplate to interconnect the various PWA

- One High Power Switch FET Module (FET: Field Effect

Transistor)

- One Input Power Filter Module




HARDWARE DESCRIPTION



ELECTRONIC CONTROL BOX - OPERATION (1)

General

The operating phases are:

- Power up

- Watch state

- Start preparation state

- Starting state

- Run state

- Cool down state

Sh td t t

Power Up State

GeneralWhen the APU master switch is selected to ON, the ECB enters thePOWER UP state.The POWER UP state lasts approximately 3 sec.OperationThe ECB checks that outputs are not energized except those thatare required.

The ECB enters self test.The ECB is able to recognize and record the occurrence of start oremergency stop signals.Upon receipt and validation of the start signal, the "start in progress"output is energized.The requirement to activate the "start in progress" output alsoapplies to the WATCH state.In case of an emergency stop signal being received the ECB closes





- Shutdown state In case of an emergency stop signal being received, the ECB closesthe air intake and deactivates the aircraft relay output once the air

intake is closed.







Watch State

General

After completion of the POWER UP state the ECB automaticallyenters the WATCH state.

Operation

The ECB is able to recognize and record the occurrence of start oremergency signals.

Upon receipt of an emergency stop signal the ECB closes the airintake and deactivates the aircraft relay output once the air intake isclosed.

The ECB self tests as required

Start Preparation State

General

Upon receipt of the start command, the ECB enters the STARTPREPARATION state.

Operation

During this state the flap actuator position, the oil level and therotation speed is checked. If the speed is greater than 7%, the startcommand will be inhibited until the speed is less than or equal to 7%.

The ECB enters the START PREPARATION state automaticallywithout requiring a new start command.





The ECB self tests as required.







Starting State - Sequences

General

The STARTING STATE is controlled by the ECB.

A stop signal at any time during the STARTING STATE willshutdown the APU.

Operation

The electrical sequences selected by the ECB are:

- Backup start contractor supply

- Gearbox de-oiling valve

- EGT rise

• Acceleration control to steady state speed control.

- At 55% speed

• Exciter de-energized

• Gearbox de-oiling valve and main start contactor de-energized.

- At 55% speed + 5 sec

• Backup start contactor de-energized.

- At 95% speed + 2 sec.

• Surge control activated





- Exciter

- Main start contactor


- Pulse fuel servo valve

- Manifold fill algorithm

- Open loop fuel schedule activation.


• APU available signal activated• Start in progress output de-activated

• Steady state speed control loop activated

• Enter RUN STATE.







Starting State- Fuel Control

General

There are three consecutive programs used to supply and meter thefuel during starting:

- Manifold Fill Algorithm

- Open Loop fuel schedule

- Acceleration control

Manifold Fill Algorithm - General

During engine start up the ECB controls the fuel servo valve toimplement the manifold fill algorithm.

Accelerat ion Control - General

This control occurs from EGT rise until steady state speed control isreached.

Fuel flow during acceleration is controlled by speed and EGT signalsto the ECB.





The control is an open loop schedule based on the rotation speed,this ends when a given quantity of fuel is delivered to the manifold.

Open Loop Fuel Schedule - General

This fuel schedule replaces the manifold fill algorithm when the flowdelivered has reached 0.01 kg/m (0.032 lb/m).

The schedule determines a fuel flow rate depending on rotation

speed, ambient pressure and temperature. It is considered the"basic" fuel flow needed to obtain combustion in the combustorchamber.




STARTING STATE - FUEL CONTROL




Run State- Fuel and Load Compressor Control

General

Upon completion of starting, three main functions are activated:

- Speed control

- Load compressor surge control

- EGT control.

Speed Control - General

The purpose of speed control is to maintain the APU at 100% speedunder all load conditions. This is accomplished by the fuel controlunit increasing or decreasing fuel flow automatically when APU loadchanges occur

Load Compressor Surge Control- General

This function prevents load compressor surge. This is accomplishedwhen the bleed switch is ON.

EGT Control - General

To prevent EGT over temperature during load compressor operation,the ECB will automatically move the IGV's to decrease airflow and

reduce the work load on the power section.

The AC generator output has priority overload compressor operation.





changes occur.

GEARBOXGEARS




G S

AMBIENT AIRCOMPRESSED AIRMETERED FUELCOMBUSTIONEXHAUST

RUN STATE - FUEL AND LOAD COMPRESSOR CONTROL - GENERAL




Cool Down State

General

This function allows the APU to operate in a no-load condition beforeentering the shutdown state.

When the APU master switch is selected to OFF, all loads areremoved (IGV's closed, Bleed Control valve to discharge).

If the APU was providing bleed air at this time, the APU will continueto run in a cool down mode for a maximum time of 2 minutes.

The cool down mode time limit can vary from 0 to 2 minutes. Thetime limit depends on when the APU bleed switch is turned off priorto selecting the APU master switch to OFF.

At the end of the cool down mode (if any) the operation enters the






SHUTDOWN STATE.




COOL DOWN STATE




Shutdown State

General

The APU enters the shutdown state after a normal shutdown or afault shutdown occurs.

Note: The APU can be re-started during the shutdown state. Thisis accomplished by cycling the master switch OFF to ON andthen selecting the APU start switch to ON.

The ECB does not close the flap and the APU automaticallyre-starts when 7% speed is reached.








SHUT DOWN STATE

ELECTRONIC CONTROL BOX – OPERATION (7)



Condition Monitor ing Data

General

For long term trend monitoring, the APU control system records theengine operating parameters.

Operation

APU conditioning monitoring parameters are taken during operationof the APU. The ECU does not store this information but it may beretrieved from the Aircraft Integrated Data System (AIDS) if thissystem is installed.

The following parameters are:

- Exhaust Gas Temperature °C

- Engine speed %

In addition, the ECB records:

- APU operating hours (in one minute increments from speed > 55%until the 3-way solenoid valve is de-energized.

- Number of starts (1 start = EGT rise detected + speed > 30%)

- ECB operating hours (in one minute increments, from ECB powerON to ECB power OFF).

The condition monitoring data is associated with the engineidentification (ID) number, ECB serial number.

Note 1: The condition monitoring parameters are not taken wheneither the inlet pressure or temperature sensors are faulty





Engine speed %

- Engine inlet pressure PSIA

- Engine inlet temperature °C

- Fuel flow LB/HR

either the inlet pressure or temperature sensors are faulty.

Note 2: If the engine ID module has been determined failed, the APU system operating history data will be associated withthe last valid engine I D number.When a new engine ID number occurs, it is used withouterasing the previously recorded historical data.The oldest data is overwritten by the new data as it isrecorded.The ECB records the condition monitoring data associated

with the last APU cycle and the data is available via the ARINC 429 link.




BUILT-IN TEST - OPERATION - POWER UP TEST





HPS CT/NOV. 2006 Page 6. 53 HAMILTON SUNDSTRAND PROPRIETARY




SECTION 7

INDICATING SYSTEM



HSPS CT/ NOV.. 2006 Page 7.0HAMILTON STANDARD PROPRIETARY


INDICATING SYSTEM

Main Components

- APU components (speed sensors, thermocouples and engine IDmodule)


- The aircraft control panel which includes:

• APU master switch and APU start switch

• ECAM, MCDU

• FUEL, AIR CONDITIONING, ELECTRIC and FIRE controlpanels

• MASTER WARNING and MASTER CAUTION LIGHTS

- The EXTERNAL CONTROL PANEL.

Note: This chapter covers the APU indicating components andprovides general information on the aircraft system.

ECAM: Electronic Centralized Aircraft Monitoring.

MCDU: Multi-function Control and Display Unit.





The EXTERNAL CONTROL PANEL.




INDICATING SYSTEM


ROTATION SPEED INDICATION SYSTEM - GENERAL

Function

The rotation speed signal is used by the ECB for:

- Indication

- Fuel metering

- ECB Sequencing

- ECB Control functions.

Main Features

Two sensors.

Interfaces

The ECB provides the speed information to the CFDS/ECAM display

Main Components

- One "phonic" wheel with 24 teeth

- Two electromagnetic sensors (single coil)

- Harness

- ECB.

Location of the Main Components

The phonic wheel is secured to the rotor front bearing journal.

The two speed sensors are located in the gearbox housing at 5o'clock and 7 o'clock. Each one is secured by a single bolt.





ysystem.




UN METERED FUELMETERED FUEL

OIL LEVEL



ROTATION SPEED INDICATION SYSTEM -DESCRIPTION AND OPERATION

Description

- Phonic wheel has 24 teeth

- Two single coil speed sensors (the coil surrounds a magnetic core)

• Phonic wheel-speed sensor gap: 0.5 mm (0.018 inch); gapnot adjustable

- The two sensors are connected to the ECB

• Frequency signal at 100 %: 19720 Hz (49300 RPM)

• Frequency signal range: 0 to 24 KHz; 0 to 50 volts.

Operation

The phonic wheel rotates with the rotor assembly, as the teeth passby each speed sensor they generate a voltage. The voltage isproportional to the speed of the phonic wheel. The signal is sent tothe ECB for speed indication and system control.

The ECB will calculate the average signal of the two speed sensors.

In the event a signal difference of 5% or more occurs, the ECB willselect the sensor indicating the highest value.

APU speed indication is displayed on the lower ECAM when the APU system page is selected.








ROTATION SPEED INDICATION SYSTEM - DESCRIPTION - OPERATION


EGT INDICATION SYSTEM - GENERAL

Function

The EGT signal is used for:

- Indication

- Load compressor control

- Sequences

- Control functions.

Main Features

The system uses K type chromel-alumel thermocouples and has acold junction compensation built into the ECB.

Interfaces

The ECB provides the EGT information to the ECAM display system

Main Components

- Two thermocouples

- Harness

- ECB.


The two thermocouples are located in the power section exhausthousing.





The ECB provides the EGT information to the ECAM display system.






EGT INDICATION SYSTEM - DESCRIPTION AND OPERATION

Functional Descripti on

Each thermocouple is secured into the exhaust housing by a bolt.

They are connected separately to the ECB.

Operation

The thermocouple generates a millivolt signal to the ECB that is usedfor engine control and indication (EGT)

The voltage value is of approximately 1 millivolt per 24°C (43°F).

The ECB compensates automatically the cold junction effect andcalculates the average EGT value.

An EGT system failure is declared if:

- EGT is lower than 120°C (250°F)





EGT is lower than 120 C (250 F)

- EGT is higher than 1200°C (2200°F).

The ECU will calculate the average signal of the two thermocouples.In the event a signal difference of 121°C (250°F) or more occurs, theECB will select the thermocouple indicating the highest value.

APU exhaust gas temperature indication is displayed on the lower

ECAM when the APU system page is selected.




EGT INDICATION SYSTEM - DESCRIPTION - OPERATION


ENGINE IDENTIFICATION MODULE

Function

To provide the engine serial number to the ECB.

Location

The module is installed on the ignition exciter support bracket (APUleft side).

Main Features

The ID module consists of a printed circuit board.


The ID module uses resistors located on a printed circuit board.

The board is housed in an electrical plug and is connected to theECB by means of 4 electrical wires.

There are 3 voltage lines V1, V2, V3 and a return line.

The engine ID number is read, validated and stored during the powerup phase of the ECB.

In case of ID module failure, the APU history data will be associatedwith the last valid ID number.

When a new engine ID number occurs, it is used without erasing thepreviously recorded historical data.










MONITORING SYSTEM - GENERAL

General

This system gives information about the APU actual status, foroperation and maintenance.

Description

Indication of operating parameters

The APU operating parameters are displayed on the lower ElectronicCentralized Aircraft Monitoring (ECAM) when the APU system pageis selected.

Maintenance and fault isolation

The ECB provides maintenance and fault information to the aircraftCentralized Fault Display System (CFDS). This information isdisplayed on the Multi-function Control and Display Unit (MCDU) inthe flight deck.

Warning messages

Warning, caution and indicating lights

MASTER WARNING, MASTER CAUTION and annunciator lightsprovide visual warning indications.

A FAULT light is incorporated in the APU master switch button, APUGEN button and APU BLEED button.

There are also the following lights:

- APU "ON" light in the APU master switch

- APU "START / ON" and APU "AVAILABLE" light in the APU startbutton

- APU GEN "OFF" light in the APU GEN button

- APU BLEED "ON" light in the APU BLEED button

- APU fire lights on the external control panel and in the flight deck.





Warning messages

APU warning messages are displayed on the upper ECAM and the APU system page appears on the lower ECAM.












SECTION 8

STARTING SYSTEM





STARTING SYSTEM - GENERAL

Function

The starting system allows the APU to be started on the ground andin flight.

Starting requires:

- The cranking of the rotor assembly

- The fuel supply

- The ignition of the air-fuel mixture

- The automatic control of starting sequences.

Starting Requirements

- Starting envelope. Normal start throughout the operating envelope:minus 300 m to 11900 m (minus 1000 ft to 39000 ft)

- Starting time from zero speed to governed speed: less than 80

Starting System Components

- Starter motor for cranking

- Ignition exciter and igniters for ignition

- Fuel system

- Control components (Electronic Control Box, APU Master Switch,External Control Panel, Fire Extinguishing Panel).





g p g pseconds

- Starting attempts: 3 consecutive starts and cooling for 1 hour.






STARTING SYSTEM - DESCRIPTION

The components involved are the starter-motor, the ignition exciter,the igniters and components of the fuel system and control system.

Starter-Motor

The electric starter motor drives the APU rotor assembly through asprag clutch.

The starter motor is mounted on the gearbox and aligned by alocating pin. A V-band clamp is used to secure the starter to the drive

pad.

A brush wear indicator pin and a starter low voltage sensingconnector are located on the front of the starter.

When brush wear reaches 75%, an indicator pin will appear in theplastic viewing window. (See Page 8.8)

Starter low voltage is sensed by the ECB through the low voltage

sensing connector.

I iti E it

Ignitor Cables

There are two igniter ignitor cables (one for each ignitor plug) thatdelivers high voltage from the exciter to the ignitors.

Ignitor Plugs

Two ignitor plugs are used to ignite the fuel in the combustorchamber. The ignitors are threaded into the combustor housing.

Control System

- Start switch and master switches

- Electronic Control Box.





Ignition Exciter

The ignition exciter is located on the left side of the APU. The exciteris a capacitor-discharge unit that uses 28V DC to provide anintermittent high voltage output to the two ignitor plugs.




ECB

STARTING SYSTEM- DESCRIPTION


STARTING SYSTEM - OPERATION

Start Selection

Starting is selected from the aircraft control panel:

- Master switch "on"

- APU system page on lower ECAM annunciates ...

- Start button.

Starting Operation

- Cranking

Energize the starter motor.

- Fuel supply

Fuel servo valve and 3 way solenoid valve energized open.

- Ignition

APU starting is controlled by the electronic control box.

The main phases are:

- Initial phase (cranking, fuel supply and ignition)

- Self-sustaining speed (de-energize the starter motor and ignitionexciter)

- 100% speed (speed governing and loading).

Shutdown Sequence

APU shut-down can be activated automatically or manually:

- Manually from the APU master switch, from the fire control panelor from the external control panel

- Automatically by the ECB fault shut-down system.

The ECB controls the fuel control unit 3 way solenoid valve. Whenthe APU is shut down manually or automatically the 3 way solenoid





Ignition exciter energized to provide ignition to the two ignitorplugs.

Starting Cycle

the APU is shut down manually or automatically the 3 way solenoidvalve is de-energized closed. The closed valve shuts off the fuel tothe fuel injectors.






STARTER MOTOR - GENERAL

Function

The electric starter motor cranks the APU during the starting state.

Location

The starter-motor is mounted by a V-band clamp on the gearboxstarter drive pad.

Main Features

- Motor type:

- Weight: 4.22 kg (9.3 lbs)

- Voltage: 24 VDC (max. 28 VDC)

- Max current: 830 A.

Main Components

- The starter motor assembly

- The V-band clamp for attachment

- Positive and negative terminals

- Visual brushwear indicator

- Starter low voltage connector.

Interfaces

- Electrical power to the starter motor is provided by the aircraftbattery system through two start contactors (backup and main)

- Starter low voltage sensing

- Starter motor clutch.





(See Page 8.3)

(See Page 8.3)






STARTER MOTOR CLUTCH

General

Function

The function of the clutch is to disengage the starter motor when the APU reaches self-sustaining speed.

Description

The clutch is a Line Replaceable Unit. It is necessary to remove the

starter motor and the bearing support assembly to extract the clutch.

The clutch assembly consists of two gears, a starter motor driveshaft, 4 bearings and a sprag clutch.

Operation

Two operating phases are considered : starter motor engaged andstarter motor disengaged.

Starter Motor Engaged

When the starter motor is operating, the sprag pawls make contactwith the starter motor shaft and the gear assembly.

Starter Motor Disengaged

At 55% speed the starter motor is de-energized by the ECB.

As the starter gear speed increases, centrifugal force moves thesprag pawls away from the starter motor shaft.

The starter motor shaft is disconnected from the sprag pawls, thisprevents the APU from driving the starter motor mechanically.








OIL SUPPLY STARTER MOTOR CLUTCH - OPERATION


IGNITION EXCITER - GENERAL

Function

The ignition exciter transforms low DC voltage into intermittent highvoltage supply to the ignitor plugs.

Location

The ignition exciter is mounted on the left side of the APU.

Main Features

- Voltage range: 10 VDC to 30 VDC

- Energy: 0.22 Joules per spark

- Spark duration: 15 microseconds

- Spark rate: 2 Hz at voltage above 10 VDC.

IGNITION EXCITER - DESCRIPTION

The ignition exciter is a sealed metal box assembly with a mounting

bracket.


- An input circuit with a connector and a DC/AC converter

- A high voltage transformer

- A high voltage output circuit with a rectifier, two capacitors and a

triggering device.

The ignition exciter DC input voltage is sensed by the ECB for faultdetection.








IGNITION EXCITER - GENERAL - DESCRIPTION


IGNITORS AND IGNITOR CABLES

Function

There are two ignitor plugs used to ignite the fuel in the combustorchamber during start up of the APU. They are connected to theignition exciter by two shielded ignitor cables.

Location

The two ignitor plugs are located on the combustor housing:

- One at 5 'o'clock

- One at 9 'o'clock.

Note: Location is looking at the combustor housing rear view.





IGNITORCABLES




IGNITORS




HSPS CT/NOV.2006 Page 8.15HAMILTON SUNDSTRAND PROPRIETARY




SECTION 9

ELECTRICAL SYSTEM





ELECTRICAL SYSTEM

Functions

To operate the electrical accessories by control signals from theECB.

To supply AC power from the APU generator to the aircraft electricalsystem.

Main Features

- DC power

- AC power.

Main Components

- The electrical accessories

- The ECB









ELECTRICAL SYSTEM


AIRCRAFT/APU HARNESS (1)

Description

ECB connectors

The ECB has 2 connectors:

- An ARINC 600-2 connector with 3 inserts (A, B, C)

- A RS 232 C connector.

The ARINC 600 connector is installed at the rear of the ECB andplugs into a shelf mounted aircraft connector.

The ARINC 600 connector carries all inputs/outputs of the ECB plusthe ARINC 429 data link.

The RS 232 connector can be accessed through the front and therear connectors for maintenance purposes.

Aircraf t harness

- DC power to ECB and start contactors

- ARINC 429 data link

- AC generator control

- AC generator excitation control

- RS 232 C connector.

There are three firewall connectors that connect the ECB to theengine harness. They are identified as (J-1, J-2 and J-3).








ECB CONNECTORS - AIRCRAFT HARNESS




Description (continued)

APU eng ine harnessThe engine harness is connected to three firewall connectors, theyare identified as (P-1, P-2 and P-3).P1 connector:- PMG- 3 way solenoid valve- Ignition exciter- Starter Motor (low voltage sense signal)

- Bleed Control Valve LVDT- Gearbox de-oiling valve- Oil filter switch indicators- Low oil pressure switch- Oil level sensor- Low fuel pressure switch- Generator high oil temperature sensor- AC generator current transformers.

P2 connector:- Load compressor discharge pressure sensors- IGV actuator (servo valve and LVDT)- BCV actuator (servo valve)- Fuel servo valve- Speeds sensor 1 and 2- Oil temperature sensor- EGT sensor 1 and 2

- Engine ID module- Air inlet pressure and temperature sensor.P3 connector:- AC generator PMG- AC generator excitation control.








APU HARNESS





Starter motor electrical power supply cables

The starter motor DC power supply is provided by the aircraftbatteries or the Transformer Rectifier Unit (TRU).

The supply is controlled by two contactors in series (backup andmain start contactors). The power cables link the start contactorsdirectly to the starter motor (+ and -cables).

AC generator harness

The AC generator connector P-4 is part of the engine harness. Theconnector provides the following signals:

- AC generator oil temperature and control signals through the P-1engine harness connector

- AC generator PMG signal and exciter field control through the P-3engine harness connector.

The four AC generator cables are connected to the aircraft electricalbuss system. Three of the cables provide AC power and the fourthcable is a neutral.








STARTER MOTOR CABLES - AC GENERATOR HARNESS



AC GENERATOR - GENERAL

Function

The AC generator (Alternating Current Generator) provides electricalpower to the aircraft systems.LocationThe AC generator is mounted on the front face of the gearbox.Type- Brushless- 3 phases- Oil cooled.Main Features

- Nominal power: 90 kVA- Output: 115 V, 400 Hz- Rotation speed: 24 034 RPM at 100 % APU speed- Direction of rotation: Clockwise viewing the pad- Weight: approx. 22.7 kg (50 lbs).

Interfaces

- Oil system (lubrication, cooling)- Generator Control Unit (GCU)- Electronic Control Box (ECB).Main Components- Permanent Magnet Generator- Current transformers- High oil temperature sensor (HOT).










ELECTRICAL SYSTEM INTERFACES

The APU AC generator is connected to the aircraft electrical systems

through the APU line contactor.

The lower ECAM, APU system page displays the AC generatorparameters:

- The percent of load

- The output voltage (115 V)

- The output frequency (400 Hz).
















SECTION 10

APU INSTALLATION



HSPS CT/NOV. 2006 Page 10.0HANMILTON SUNDSTRAND PROPRIETARY


APU COMPARTMENT

The APU compartment is located inside the aircraft tail cone.

The compartment is fire proof using firewalls made of titanium alloy.

Two longitudinally-hinged access doors provide access to the APUcompartment.

The air inlet duct assembly is attached to the right access door andprovides a ducted airflow to the APU air inlet plenum.

The APU compartment has a fire extinguishing bottle located in aseparate compartment, forward of the firewall.

Cooling and ventilation of the compartment is provided by the APUcooling fan. The fan provides air flow to the oil cooler and the APUcompartment.





APU COMPARTMENT AMBIENT AIRCOMPRESSED AIREXHAUST GAS





APU ATTACHMENT

The APU is attached to the aircraft tail cone structure by three struts.

The struts are connected to the APU through vibration isolators.

The two forward struts are attached to mounts on each side of thegearbox. The rear strut is attached to the power section impellercontainment shield.

A lifting eye is also provided for installation and removal of the APU.









APU ATTACHMENT

AIR INLET SYSTEM

Function

The air inlet system provides ambient air to the APU air inlet plenum.

Location

The air inlet is located on the underside of the tail section.

System Components

The air inlet system includes:

- The diverter

- The air inlet

- The diffuser

- The elbow

- The interface with the APU inlet plenum.

The Diverter directs ambient air flow into the air inlet when the

aircraft is operating at high airspeeds.

The Air Inlet has a flap that is opened and closed by an electricactuator. The actuator is controlled by the ECB.

The Diffuser slows the airflow delivery to the APU.

The Elbow is attached to the diffuser and directs the ambient airflowinto the APU air inlet plenum.

The air inlet duct assembly is secured to the right access door andcan be removed to provide better accessibility to the APU.





AMBIENT AIR




AIR INLET SYSTEM


EXHAUST SYSTEM

Function

The exhaust system directs the APU exhaust gasses overboard.

Location

The system is installed in the tail cone between the APU exhaustand the end of the tail cone.

System Components

- The exhaust pipe

- The exhaust muffler

- The insulation

- The sealing ring.

The exhaust pipe is mounted on rails that are attached to the insideof the tail cone.

This allows the exhaust pipe to be disconnected from the APU andmoved rearward to provide additional clearance during removal andinstallation of the APU.





EXHAUST GAS





EXHAUST SYSTEM

DRAIN SYSTEM (1)

Function

The APU drain system provides drains from various components.The fluids are collected and drained overboard through the drainmast.

The fuel control unit, BCV actuator and IGV actuator use a commondrain to the aircraft drain tank. Fluids are siphoned from the draintank, into the drain mast and then discharged overboard when theaircraft is in flight.

The other common and single drains flow directly into the drain mastand then discharge overboard.

APU Drains and Vent

- Combustor Drain

- Air Bypass Plenum Drain

- Exhaust Pipe Drain

- Front Bearing Seal Drain

- Fuel Control Unit Drain

- Flow Divider Purge Drain (To exhaust)

- Gearbox Vent (To exhaust).





- BCV Actuator Seal Drain

- IGV Actuator Seal Drain

SIPHON TUBE

COLLECTORTANK





DRAIN SYSTEM (1)

DRAIN FLUID

FIRE PROTECTION

APU fire protection consists of a detection system and anextinguishing system. The systems are supplied by the aircraftmanufacturer.

Fire Detection and Extinguish ing

The detection system uses two continuous sensing elementsinstalled on the APU compartment walls.

One fire bottle is available for fire extinguishing. The bottle isinstalled on the forward side of the APU compartment firewall.

Operation

The APU fire control panel is located in the flight deck overheadpanel.

Pushing the fire switch will immediately shut down the APU and armthe fire extinguishing system.

In the event of an APU fire on the ground, the APU will automaticallyshutdown and discharge the extinguishing system.








FIRE PROTECTION








SECTION 11

MAINTENANCE





INSPECTION AND CHECKS

Visual Inspections

Opening the APU compartment for corrective maintenance orservicing provides the opportunity to visually inspect the APU forsecurity, leaks, and warning indicators. The following arerecommended inspection items:

- Engine mounts

- Engine Components and Fluid lines

- Oil Quantity and Magnetic Drain plug

- Oil and Fuel Filter impending blockage Indicators

- Electrical harness and Connectors

- Engine Air Inlet Plenum

- Engine Combustor Housing and Exhaust System.

Borescope Inspection

The APU internal components may be inspected by using a flexibleborescope. To rotate the APU internal components, the cooling faninlet duct may be removed to allow manual rotation of the fanimpeller.

The following components can be inspected with the APU installed inthe aircraft.

- Load compressor impeller and guide vanes

- Power section impeller

- Combustor, viewed through the ignitor and fuel injector bosses

- First stage turbine wheel

- Second stage turbine wheel.

Refer to the Aircraft Maintenance Manual for borescopeprocedures.








VISUAL INSPECTIONS - BORESCOPE INSPECTION



LINE REPLACEABLE UNITS

The following Line Replaceable Units (LRU's) can be removed andreplaced without removing the APU from the aircraft:

Electronic Control BoxEngine HarnessIdentification ModuleStarter MotorClutch AssemblyIgnition Exciter

Ignitor CablesIgnitor PlugsSpeed SensorsThermocouples

Air Inlet Pressure And Temperature SensorOil Filter ElementsSwitch IndicatorsMagnetic Drain PlugDe-Oiling ValveLow Oil Pressure SwitchOil Temperature SensorOil Level SensorOil Pressure Relief ValveOil CoolerFuel Control UnitFuel Filter ElementFlow Divider Assembly

Pilot Fuel InjectorsMain Fuel InjectorsInlet Guide Vane ActuatorBleed Control ValveCompressor Discharge SensorCooling Fan Assembly

AC Generator PadFuel and Oil PipesCombustor Chamber Drain Valve





Flow Divider AssemblyPilot Manifold AssemblyMain Manifold Assembly


STARTER

ENGINEHARNESS

OIL COOLER

FUEL CONTROLUNIT

DE-OILING

IDENTIFICATIONMODULE

IGNITION

EXCITER





LEFT FRONT-TOP VIEW

UNITDE OILINGVALVE

INLET GUIDEVANE

ACTUATOR

BLEEDCONTROLVALVE

COMPRESSORDISCHARGE


SENSOROILLEVELSENSORSPEED





RIGHT FRONT TOP VIEW

SENSORSENSOR

SWITCHINDICATORS

MAGNETIC

GENERATORSCAVENGEFILTER

LUBRICATIONFILTER

OIL PRESSURE




DRAIN PLUG REIEF VALVE

RIGHT FRONT BOTTOM VIEW


THERMOCOUPLE

IGNITORCABLES

OIL TEMPERATURESENSOR

SPEEDSENSOR

FUELFILTER

PILOTMANIFOLD

ASSEMBLY

IGNITOR

FUEL FLOWDIVIDER

ASSEMBLY

MAINMANIFOLD

ASSEMBLY




SENSOR

LEFT REAR BOTTOM VIEW


AIR INLET AND

TEMPERATURESENSOR

LOW OILPRESSURE SWITCH

NOTE:(The switch may alsobe Located on thelower right side of




the gearbox)

RIGHT REAR TOP VIEW


THEMOCOUPLE

IGNITOR

COMBUSTORDRAIN CHECKCHECK VALVE

MAIN FUELINJECTOR

PILOT FUELINJECTOR

AIR INLET ANDTEMPERATURE




SENSOR

RIGHT REAR BOTTOM VIEW


APS 3200


SECTION 12

FAULT ISOLATION

VERSION 6.0





GENERAL DESCRIPTION

The centralized fault display system (CFDS) provides electronicsystem fault detection, fault storage, fault displays, operationaltesting and troubleshooting from the flight deck multi-purpose controland display unit (MCDU).

CENTRALIZED FAULT DISPLAY AND INTERFACE UNIT

The CFDIU provides the interface between the APU electroniccontrol box (ECB) and the MCDU for screen display of APU faultinformation.

MULTIPURPOSE CONTROL AND DISPLAY UNITS

The Multipurpose Control and Display Unit (MCDU) is a display unitand a keyboard used by the CFDS to display and interrogate faultsand to initiate system tests. Both MCDU's (Multipurpose Control andDisplay Unit) are connected to the CFDS.

Only one MCDU can be used when interrogating the CFDS.

CFDIU/PRINTER INTERFACE

The CFDIU sends MCDU screen information and print commands tothe optional printer automatically or on request.

CFDIU/ACARS INTERFACE

The CFDIU sends fault information to the optional ACARS for down-linking when selected manually by the MCDU operator or when anuplink request is received from a ground station via the ACARSmanagement unit.



HSPS CT/NOV. 2006 Page 12.1HAMILTO SUNDSTRAND PROPRIETARY


MCDU - 2

MCDU - 1




CENTRALIZED FAULT DISPLAY SYSTEM


APU FAULT WARNINGS

Flight Deck Fault Warnings are identified as Class 1, 2 and 3.Class 1 faults are further identified as Level 3, 2 and 1.

CLASS 1

- Level 3- This level corresponds to warnings needing immediate

action.- Level 3 warnings are associated with:

- Repetitive chime- Warning message on upper ECAM display- Master Warning Light flashing Red

- APU systems page on lower ECAM display

- Level 2- This level corresponds to abnormal situations needing

immediate awareness but not immediate action.- Level 2 warnings are associated with:

- Single chime- Master caution steady Amber light- Warning messages on upper ECAM display

- APU system page on lower ECAM displayLevel 1- This level corresponds to reduced bleed air performance- It is associated with low or zero duct pressure- Low or zero duct pressure is visible (lower ECAM display) on

the engine system page during MES or on the APUsystem page.

CLASS 2

- These failures are indicated on the STATUS page, under the title

of MAINTENANCE.- They are also accessible through the CFDS.

indicates that the STATUS page is not empty andflashes in flight phase 10 on the upper ECAM display.STS

CLASS 3

- These failures are only accessible through the CFDS. No APUfault warnings are displayed.







APU FAULT WARNINGS

STATUS

STATUS (STS) indication is an "attention getter" on the upper ECAMdisplay.

STATUS (STS) indicates that a status message (class 1 or class 2fault) is present and further maintenance action may be required. Aflashing STS indication occurs after the second engine shutdown inFlight Phase 10. It is necessary to press the STS key on the ECAMcontrol panel for the STATUS page to appear on the lower ECAMdisplay.








UPPER ECAM ADVISORY AND STATUS DISPLAY


APU FAULT WARNINGS

ECAM CONTROL PANEL

The control panel allows selection of the aircraft system pageincluding APU. Pressing the Status (STS) key presents the STATUSpage on the lower ECAM display. The STATUS page will indicate thefaulty aircraft systems under the INOP SYS (Class 1 Fault) andMAINTENANCE (Class 2 Fault) titles.












The Multipurpose Control and Display Unit (MCDU) is a display unitand a keyboard used by the CFDS to display and interrogate faults

and to initiate system tests. Both MCDU's (Multipurpose Control andDisplay Unit) are connected to the CFDS.


Pressing the MCDU MENU key, the MCDU menu page is displayed,and any one of the systems connected to the MCDU can beselected.

A multiple page display is indicated by an arrow (∇) in the right uppercorner of the screen. In this case the NEXT PAGE key must be usedto provide access to the various pages of the display. The NEXTPAGE key can be used as long as the arrow is displayed.

Twelve line select keys, six on the left and six on the right, provideaccess to a page or a function. The line select keys permit access toa page or a function when these prompt symbols appear (>, <). Theyare identified as 1L to 6L on the left, and 1R to 6R on the right.

If a flight deck printer is installed and operational, the current MCDUdisplay screen may be printed by pushing the PRINT line select key.

APU FAULT OPERATION

SYSTEM SELECTION

The MCDU MENU page is displayed when the MCDU MENU key ispushed.

Selecting the CFDS line select key will then display CFDS menu.

Pressing the SYSTEM REPORT/TEST line select key displays theSYSTEM REPORT TEST menu.








MULTIPURPOSE CONTROL AND DISPLAY UNIT


APU FAULT OPERATION

SYSTEM REPORT/TEST

When SYSTEM REPORT/TEST is selected while on the ground, asystems menu is displayed. The APU selection is located on thesecond page of the menu. Pushing the NEXT PAGE key will display

APU.

Selection of the RETURN line select key on the first page will displayMCDU MENU.

Selection of the RETURN line select key on the second page will

display the first page of SYSTEM REPORT/ TEST.

APU

There are two APU menu pages available. The first page displaysthe following information:

LASTLEGREPORT

PREVIOUSLEGREPORT

LRUIDENTIFICATION

SYSTEMSELF-TEST

SHUTDOWNS

The second page of the APU menu when selected by theNEXTPAGE key, displays the following information:

APUDATA/OIL

CLASS3FAULTS

Selection of the RETURN line select key on the First Page willdisplay the Second Page of SYSTEM REPORT/TEST.Selection of the RETURN line select key on the (Second Page) willdisplay the (First Page) of APU menu.







HSPS CT/NOV. 2006 Page 12.12O SUNDSTRAND PROPRIETARYHAMILT


APU FAULT OPERATION

APU LAST LEG REPORT

The Last Leg Report displays fault information delivered by theCFDS system. It can store up to 40 failures during the Last Leg. TheLast LEG Report displays only class 1 and 2 faults and contains theidentity of each LRU, its corresponding Date, GMT, ATA chapter andFault Code Number (FCN) for each fault occurrence. The FunctionalIdentification Number (FIN) appears after each LRU. In the case ofmultiple failures, the failures will be displayed in chronological orderwith two failures per page. A maximum count of four intermittentfaults will only be displayed in the same flight leg. Prompts (>) at the

end of each LRU message indicate the line select key to display the APU FAULT CONDITIONS screen. All of the Last Leg Report isprinted when the PRINT line select key is pushed, even if it containsseveral pages.

Selection of the RETURN line select key will display APU menu,(First Page).

APU PREVIOUS LEGS REPORT

The Last Leg Report contents are transferred into the Previous LegReport with each new flight leg. The report can store up to 200failures over the last 63 flight legs. Each LRU is identified along withthe Aircraft identification, Leg number, Date, GMT, ATA chapter andFault Code Number (FCN) for each fault occurrence. The FunctionalIdentification Number (FIN) appears after each LRU. In the case ofmultiple failures, the failures will be displayed in reversechronological order with two failures per page. Prompts (>) at theend of each LRU message indicate the line select key to display the

APU FAULT CONDITIONS screen. Only the PREVIOUS LEGSREPORT displayed page will be printed when the PRINT line selectkey is pushed.






APU LAST LEG REPORT APU PREVIOUS LEGS REPORT





APU FAULT OPERATION

APU LRU IDENTIFICATION

The LRU Identification page displays the ECB Part Number, ECBSerial Number and the ECB Software Version.

The ECB part number is adjustable and is stored in the NVM. Thebuilt letter (H) following the part number is adjustable from A to Z.


APU SYSTEM SELF TEST

A self test of LRU's may be initiated through the CFDS. The test canonly be accomplished when the APU is not running and the MasterSwitch is ON. In case of no failures or when the test is in progress, orlack of availability of the test function, the message of TEST OK, INPROGRESS and NOT AVAILABLE will be displayed respectively.Detected failures will be displayed with their ATA Chapter and FaultCode Number (FCN). The Functional Identification Number (FIN)appears after each LRU. In the case of multiple failures, the failureswill be displayed in chronological order with two failures per page.

Only the SYSTEM SELF TEST displayed page will be printed whenthe PRINT line select key is pushed.










APU FAULT OPERATION

APU SHUTDOWNS

The Shutdowns page contains its corresponding Date, GMT, FaultCode Number (FCN), shutdown message and the identity of theLRU. The Shutdowns will be displayed in reverse chronological orderwith only one shutdown per page. Prompts (>) at the end of eachLRU message indicate the line select key to display the APU FAULTCONDITIONS screen.

In case there are no shutdowns, the message of NO SHUTDOWNSwill be displayed. Only the SHUTDOWNS displayed page will be

printed when the PRINT line select key is pushed.


APU DATA/OIL

APU Data/Oil page contains the Date, APU Serial Number (S/N),Hours, Start Attempts, Start Cycles and Oil level status. Prompts (>)at the end of the message indicate the line select key to display the"Update APU Data" screen.

Selection of the RETURN line select key will display APU menu,(Second Page).









APU FAULT OPERATION

APU CLASS 3 FAULTS

Class 3 Faults can be stored up to 200 failures over the last 63 flightlegs. Each LRU is identified along with the Aircraft identification, Legnumber, GMT, ATA chapter and Fault Code Number (FCN) for eachfault occurrence. The Functional Identification Number (FIN) appearsafter each LRU. In the case of multiple failures, the failures will bedisplayed in reverse chronological order with two failures per page.Prompts (>) at the end of each LRU message indicate the line selectkey to display the APU FAULT CONDITIONS screen.

In case there are NO CLASS 3 FAULTS detected, the message NOFAULTS will be displayed. Only the CLASS 3 FAULTS displayedpage will be printed when the PRINT line select key is pushed.










APU FAULT OPERATION

UPDATE APU DATA

Selection of this screen allows the operator to update the APU hoursand cycles when the ECB or the APU is changed.The Update APU Data screen is only accessible by prompts (>) fromthe APU Data/Oil Screen. The Update APU Data screen displays the

APU Serial Number (S/N), and current values of Hours and Cycles.The new values of hours and cycles can be entered by use of MCDUkeyboard. After line key 3L is pressed (Prompt <) the screen willdisplay the new values for APU hours and cycles when the ECB or

APU is changed.

The HOURS and CYCLES will be printed when the PRINT line selectkey is pushed.

Selection of the RETURN line select key will display the APUDATA/OIL screen.





HSPS CT/NOV 2006 P 12 22





HSPS CT/NOV 2006 Page 12 23

APU FAULT OPERATION

FAULT CONDITIONS

The Fault Conditions screens are only available by the line selectkeys indicated by prompt (>) on the Last Leg Report, Previous LegsReport, Shutdown and Class 3 fault screens. Selection will displaythe Fault Conditions screen-1 or screen-2. Each screen will displaythe APU S/N, Date, GMT and the identity of the LRU. The FunctionalIdentification Number (FIN) appears after the LRU.Engine data from the fault data stored in the Electronic Control Boxnon-volatile memory will also appear on each screen. (See Screen-1and Screen-2 Parameters on page 12-24).

One screen at a time is displayed. To select screen-2 when screen-1is displayed or select screen-1 when screen-2 is displayed it isnecessary to press the NEXT PAGE key on the Multipurpose Controland Display Unit (MCDU).

Only the screen that is displayed (Screen-1 or Screen-2) will beprinted when the PRINT line select key is pushed.

Selection of the RETURN line select key will display the screen that

was shown preceding selection of the Fault Selection Screens.











FLIGHT DECK PRINTER

The Printer provides onboard printouts concerning various aircraftsystems, one at a time.

MANUAL PRINT

In manual mode, prints of the MCDU screen display are printedwhen the PRINT line select key is pushed.

AUTOMATIC PRINT

In flight phase 10, the Post Flight Report will be automaticallyprinted. The Post Flight Report is the sum of the LAST LEGREPORT and the LAST LEG ECAM REPORT.

A list of ECAM Warnings and Fault Messages with the associatedtime and ATA chapter references are provided on the printed tape.






FLIGHT DECK PRINTER






FAULT CHARTS

The following Fault Charts provide the information that will be sent tothe CFDS by the ECB in the event of a fault.

The information appears in the Fault Chart columns located underthe following headings:

Version 5.0

MCDU LRU MessageMCDU Shutdown MessageFault CodeFault ClassLRU ID

ATA ChapterSystem Severity level

SYSTEM SEVERITY LEVEL

System Severity Levels are not sent to the CFDS. It is presentedhere only as information.

Once a fault has been identified with a switch or a sensor thatcomponent will no longer be used for further fault detection, isolationor control until the fault is no longer present. Detected faults can becleared and a restart may be possible once the master switch iscycled.

SYSTEMSEVERITY LEVEL ECB ACTION ECB MESSAGE

1 SHUTDOWN TRANSMIT FAULTMESSAGE


3 SHUTDOWN IF REDUNDANTSOURCE NOT AVAILABLE

TRANSMIT FAULTMESSAGE

4 CONTINUE TO OPERATE TRANSMIT FAULTMESSAGE

X NOT APPLICABLE



gHAMILTO SUNDSTRAND PROPRIETARY


HSPS CT/ NOV. 2006 Page 12.28

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FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


BLD FLOW XDCR (8039KM) 0 1 13 495112 4 4 4 4 4 4 4 4

BLD FLOW XDCR (8039KM) 1 1 13 495112 4 4 4 4 4 4 4 4

COOLING FAN PMG ASSY (8055KM) 2 1 53 495253 X X X 4 4 4 4 X

BLD FLOW XDCR (8039KM) 3 1 13 495112 4 4 4 4 4 4 4 4

INLET T-P SNSR (8013KM) 4 1 29 492317 4 4 4 4 4 4 4 4

INLET T-P SNSR (8013KM) 5 1 29 492317 4 4 4 4 4 4 4 4

INLET T-P SNSR (8013KM) 6 1 29 492317 4 4 4 4 4 4 4 4

(BLANK) 7

INLET T-P SNSR (8013KM) 8 1 29 492317 4 4 4 4 4 4 4 4

INLET T-P SNSR (8013KM) 9 1 29 492317 4 4 4 4 4 4 4 4

GENERATOR (8XS) 10 3 25 242351 3 3 3 3 3 3 3 3

GENERATOR (8XS) 11 3 25 242351 3 3 3 3 3 3 3 3

OIL TEMP SNSR (8084KM) 12 3 38 499151 3 3 3 3 3 3 3 3

OIL TEMP SNSR (8084KM) 13 3 38 499151 3 3 3 3 3 3 3 3

ECB (59KD) 14 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 15 3 14 496134 4 4 4 4 4 4 4 4

DE-OILING SOL (8083KM) 16 3 12 499149 4 X X 4 X X 4 4

CONTACTOR (5KA) 17 1 59 494255 X X X 4 X X X X







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FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


WRG: ECB PIN AB-H9 19 3 45 496100 X X X 4 X X X X

WRG: ECB PIN AB-J6 20 3 3 496100 X X X X 4 4 X X

FUEL CTL UNIT (8022KM) 21 1 21 493211 4 X X 4 4 4 X 4

WRG: ECB PIN AB-H8 22 2 6 496100 X X X X 4 X X X

EXCITER SHORTED 23 1 26 494138 X X X 4 X X X X

ECB (59KD) 24 2 14 496134 4 4 4 4 4 4 X 4INLET FLAP ACTR (4015KM) 25 2 2 491651 4 4 X X X X 4 4

INLET FLAP ACTR (4015KM) 26 2 2 491651 4 4 X X X X 4 4

ECB (59KD) 27 3 14 496134 4 4 X X X X 4 4

ECB (59KD) 28 3 14 496134 3 3 3 3 3 3 3 3

SPEED SNSR1 (8060KM1) 29 3 40 497113 X X 3 3 3 3 3 X

ECB (59KD) 30 3 14 496134 X X X 3 3 3 X X

ECB (59KD) 31 3 14 496134 3 3 3 3 3 3 3 3

SPEED SNSR2 (8060KM2) 32 3 42 497113 X X 3 3 3 3 3 X

SPEED SNSR1 (8060KM1) ANDSPEED SNSR2 (8060KM2)

LOSS OF SPEED 33 1 44 497113 1 1 1 1 1 1 1 1

(SPEED SENSORS DO NOT MATCH - NO TEXT) 34 3 NO TEXT 4 4 4 4 4 4 4 4

EGT TC1 (8075KM1) 35 3 15 497215 X X X 3 3 3 X X

EGT TC1 (8057KM1) 36 3 15 497215 3 3 3 3 3 3 3 3






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EGT TC2 (8057KM2) 37 3 18 497215 X X X 3 3 3 X X

EGT TC2 (8057KM2) 38 3 18 497215 3 3 3 3 3 3 3 3

GEN SCAN FILTER (8069KM) ANDLUB FILTER (8076KM)

39 2 7 499141 4 4 4 4 4 4 4 X

- LOSS OF DC POWER 40 1 - - X X X 1 1 1 X X

SERIAL NUMBER ENCODER (8061KM) 41 3 39 497331 4 X X X X X X 4

IGNITION UNIT (8030KM) NO FLAME 42 1 26 494138 X X X 1 X X X X

ECB (59KD) NO FLAME 42 1 14 496134 X X X 1 X X X X

FUEL CONTROL UNIT (8022KM) NO FLAME 42 1 21 493211 X X X 1 X X X X

CHECK APU FUEL SUPPLY NO FLAME 42 1 70 282200 X X X 1 X X X X

IGNITION UNIT (8030KM)FUEL CONTROL (8022KM)

NO FLAME 42 1 27 494138 X X X 1 X X X X

OIL PRESS SW (8091KM) 43 2 36 499414 4 4 X X X X X 4

CHECK OIL LEAKAGE/OIL PRESS SW (8091KM) LOW OIL PRESSURE 44 1 37 499100 X X X 2 2 2 X X


CHECK OIL COOLER ASSY HIGH OIL TEMPERATURE 46 1 9 499144 X X X 2 2 2 X X

CHECK OIL SYSTEM/GENERATOR (8XS) GEN HIGH OIL TEMP 47 1 24 499100 X X X 2 2 2 X X

LOW OIL LEVEL 48 2 32 499300 4 4 X X X X X 4

OIL LEVEL SNSR (8089KM) 49 2 35 499317 4 4 X X X X X 4







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FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


ACFT BAT NOT SELECTED/CONTACTOR (5KA) NO ACCELERATION 51 1 11 243800 X X X 1 X X X X

CONTACTOR (5KA) NO ACCELERATION 51 1 59 494255 X X X 1 X X X X


CURRENT LIMITER (6KA)/CONTACTOR (10KA) NO ACCELERATION 51 1 51 494200 X X X 1 X X X X

STATOR MOTOR (8KA)/STARTERCLUTCH(8033KM)

NO ACCELERATION 51 1 46 494251 X X X 1 X X X X

ECB (59KD) NO ACCELERATION 52 1 14 496134 X X X 1 X X X X

FUEL CTL UNIT (8022KM) NO ACCELERATION 52 1 21 493211 X X X 1 X X X X

CHECK APU FUEL SUPPLY NO ACCELERATION 52 1 70 282200 X X X 1 X X X X

FUEL CTL UNIT (8022KM)/FLOW DIVIDER(8024KM)




DE-OILING SOL (8083KM) NO ACCELERATION 53 1 12 499149 X X X 2 X X X X

IGV ACTR (8014KM) NO ACCELERATION 53 1 28 492351 X X X 2 X X X X

STARTER MOTOR (8KA)/BLD CTL VLV (8051KM) NO ACCELERATION 53 1 46 494251 X X X 2 X X X X

FLOW DIVIDER (8024KM) NO ACCELERATION 53 1 68 493213 X X X 2 X X X X

FLOW CTL UNIT (8022KM) NO ACCELERATION 53 1 21 493211 X X X 2 X X X X

ECB (59KD) 54 3 14 496134 4 X X X X X X 4

ECB (59KD) 55 3 14 496134 4 X X X X X X 4






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FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


ECB (59KD) 56 3 14 496134 4 X X X X X X 4

INLET FLAP ACTR (4015KM) 57 2 2 491651 4 4 4 4 4 4 4 4

INLET FLAP ACTR (4015KM) 58 2 2 491651 X 4 4 4 X X 4 4

FUEL CTL UNIT (8022KM) 59 1 21 493211 4 X X X X X X 4


ECB (59KD) ECB FAILURE 61 1 14 496134 X X X 2 2 2 X XIGV ACTR (8014KM) 62 1 28 492351 X X X X 4 X X X

IGV ACTR (8014KM) 63 1 28 492351 X X X X 4 X X X

ECB (59KD) 64 2 14 496134 X X X X 4 X X X

(BLANK) 56

ECB (59KD) 66 2 14 496134 X X X X 4 X X X

ECB (59KD) UNDERSPEED 67 1 14 496134 X X X X 1 1 X X

CHECK APU FUEL SUPPLY UNDERSPEED 67 1 70 282200 X X X X 1 1 X X

FUEL CTL UNIT (8022KM) UNDERSPEED 67 1 21 493211 X X X X 1 1 X X

SPD SNSR1 (8060KM1) ANDSPD SNSR2 (8060KM2)

OVERSPEED 68 1 44 497113 X X X 1 1 1 X X

ECB (59KD) OVERSPEED 68 1 14 496134 X X X 1 1 1 X X

FUEL CTL UNIT (8022KM) OVERSPEED 68 1 21 493211 X X X 1 1 1 X X

BLEED CTL VLV (8051KM) 69 1 5 495153 X X X X 4 X X X






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FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER



ECB (59KD) 71 1 14 496134 X X X X 4 X X X

(BLANK) 27

ECB (59KD) 73 2 14 496134 X X X X 4 X X X

ECB (59KD) ECB FAILURE 74 1 14 496134 1 X X X X X X X

ECB (59KD) 75 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 76 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 77 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 78 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 79 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 80 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 81 3 14 496134 4 X 4 4 4 4 X 4

ECB (59KD) 82 2 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 83 3 14 496134 4 4 4 4 4 4 4 4


ACFT BAT NOT SELECTED/CONTACTOR (5KA)

85 1 11 243800 X X X 4 X X X X








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FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER





IGNITION UNIT (8030KM) 91 1 26 494138 X X X 4 X X X X

SPEED SNSR1 (8060M1) 92 3 40 497113 3 3 3 3 3 3 3 3

SPEED SNSR1 (8060M1) 93 3 40 497113 3 3 3 3 3 3 3 X

SPEED SNSR2 (8060KM2) 94 3 42 497113 3 3 3 3 3 3 3 3

SPEED SNSR2 (8060KM2) 95 3 42 497113 3 3 3 3 3 3 3 X

BLEED CTL VLV (8051KM) 96 1 5 495153 X X X X 4 4 X X

BLEED CTL VLV (8051KM) SURGE/REVERSE FLOW 97 1 5 495153 X X X X 2 2 X X

IGV ACTR (8014KM) OVERTEMPERATURE 98 1 28 492351 X X X 2 2 2 X X

EGT TC1 (8057KM1) OVERTEMPERATURE 98 1 15 497215 X X X 2 2 2 X X


FUEL CTL UNIT (8022KM) OVERTEMPERATURE 98 1 21 493211 X X X 2 2 2 X X

FUEL CTL UNIT (8022KM) 99 1 21 493211 X X X X X X 1 X

ECB (59KD) 100 2 14 496134 3 X X X X X X 3

ECB (59KD) 101 2 14 496134 3 X X X X X X 3

EGT TC1 (8057KM1) ANDEGT TC2 (8057KM2)

SENSOR FAILURE 102 1 16 497215 2 2 2 2 2 2 2 2





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FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


BLD FLOW XDCR (8039KM) 103 1 13 495112 4 4 4 4 4 4 4 4

ECB (59KD) ECB FAILURE 104 1 14 496134 1 1 1 1 1 1 1 1


NO DATA FROM ECS 106 3 34 216334 X X X X 4 X X X

ECB (59KD) 107 2 14 496134 X 4 4 4 4 4 4 4

ECB (59KD) ECB FAILURE 108 1 14 496134 X 1 1 1 1 1 1 1




FUEL LOW PRESS/LOW FUEL PRESS SW(5030QM)

112 2 31 282214 X X X 4 4 4 X X

- EMERGENCY STOP 113 1 NO TEXT - 1 1 1 1 1 1 1 1

COOLING FAN PMG ASSY (8055KM) SENSOR FAILURE 114 1 53 495253 X X X 1 X X X X

ECB (59KD) BACKUP OVERSPEED 115 1 14 496134 X 1 1 1 1 1 1 1


BACKUP OVERSPEED 115 1 44 497113 X 1 1 1 1 1 1 1

FUEL CTL UNIT (8022KM) BACKUP OVERSPEED 115 1 21 493211 X 1 1 1 1 1 1 1

COOLING FAN PMG ASSY (8055KM) BACKUP OVERSPEED 115 1 53 495253 X 1 1 1 1 1 1 1

ECB (59KD) BACKUP OVERSPEEDCIRCUIT FAILURE

116 1 14 496134 1 X X X X X X X





P OWE R UP

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OWN

S H UT D OWN

S E L F T E S T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


ECB (59KD) 117 1 14 496134 4 X X X X X X 4

CHECK APU FUEL SUPPLY 118 1 70 282200 X X X X 4 4 4 X

IGV ACTR (8014KM) 118 1 28 492351 X X X X 4 4 4 X


BLEED CTL VLV (8051KM) 119 1 5 495153 X X X X 4 4 4 X

INLET FLAP ACTR (4015KM) 120 2 2 491651 X X X X X X 4 X

INLET FLAP ACTR (4015KM) AIR INTAKE NOT OPEN 121 1 2 491651 X 1 1 X X X X 1

OIL TEMP SNSR (8084KM) AND GENERATOR(8XS)`

SENSOR FAILURE 122 1 50 499151 2 2 2 2 2 2 2 2

ECB (59KD)/APU HARNESS (8001KM) 123 1 8 496134 4 4 4 4 4 4 4 4

WRG: ACFT TYPE PIN/FCB (59KD) 124 3 47 496100 4 X X X X X X X

WRG: ECB PIN AB-H5 125 3 4 496100 4 4 4 4 4 4 4 4

CURRENT LIMITER (6KA)/CONTACTOR (10KA) 126 1 51 494200 X X X 4 X X X X





(BLANK) 131

ECB (59KD) ECB FAILURE 132 1 14 496134 1 X X X X X X 1





P OWE R UP

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OWN

S H UT D OWN

S E L F T E S T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


FIRE EMERG-STOP RELAY (6WF) 133 3 54 262200 X X X X X X 4 X

FIRE EMER STOP RELAY (6WF) 134 3 54 262200 X X X X X X 4 X

ECB (59KD) 135 3 14 496134 X 4 4 4 4 4 4 X

(EMERGENCY STOP TEST - NO TEXT) 136 3 NO TEXT - 4 4 X X X X X X

(BLANK) 137

BLEED CTL VLV (8051KM) 138 1 5 495153 X X X 4 X X X X

IGV ACTR (8014KM) 139 1 28 492351 X X X 4 X X X X

OIL PRESS SW (8091KM) AND OIL LVL SNSR(8089KM)

SENSOR FAILURE 140 1 55 499414 2 2 X X X X X 2

OIL PRESS SW (8091KM) AND LOW OIL LEVEL SENSOR FAILURE 141 1 56 499414 2 2 X X X X X 2

ECB (59KD) LOSS OF SPEED 142 1 14 496134 1 1 1 1 1 1 1 1



SPD SNSR1 (8060KM1) AND ECB (59KD) LOSS OF SPEED 145 1 41 497133 1 1 1 1 1 1 1 1


(BLANK) 147

(BLANK) 148

BLD FLOW XDCR (8039KM) 149 1 13 499112 X X X 4 4 4 4 X

ECB (59KD) ECB FAILURE 150 1 14 496134 X 1 1 1 1 1 1 X





P OWE R UP

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OWN

S H UT D OWN

S E L F T E S T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER














ECB (59KD) ECB FAILURE 163 1 14 496134 X 1 1 1 1 1 1 XECB (59KD) ECB FAILURE 164 1 14 496134 X 1 1 1 1 1 1 X

ECB (59KD) 165 3 14 496134 4 4 4 4 4 4 4 X

ECB (59KD) 166 3 14 496134 X 4 4 4 4 4 4 X


ECB (59KD) APU FUEL VALVE FAILED OPEN 168 1 14 496134 X 1 X X X X 1 X





P OWE R UP

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OWN

S H UT D OWN

S E L F T E S T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


BLD FLOW XDCR (8039KM)/BLD CTL VLV (8051KM)

169 1 48 495112 X X X X 4 4 X X

INLET T-P SNSR (8013KM) 170 1 29 492317 4 4 4 4 4 4 4 4

BLD FLOW XDCR (8039KM) 170 1 13 495112 4 4 4 4 4 4 4 4

BLD FLOW XDCR (8039KM) 171 1 13 495112 X X X X 4 X X X



BLEED CTL VLV (8051KM)/FUEL CTL UNIT (8022KM)

174 1 69 495153 X X X X 4 X X X






SECTION 13

TROUBLESHOOTING





TROUBLESHOOTING

GENERAL

The troubleshooting system is designed to provide additional

information to aid in the maintenance and repair of the AuxiliaryPower Unit (APU) by downloading the Electronic Control Box (ECB)located in the aircraft aft cargo compartment.Maintenance information is stored in the nonvolatile memory of theECB and can be retrieved and analyzed by downloading into alaptop computer. The computer displays information andrecommended actions from the following stored data:

CONDITIONING MONITORING DATA

This data consists of engine parameters taken at each engine startand shutdown. Data is provided for the last twelve engine run cycles.

FAULT DATA

The data consists of maintenance and fault messages for class 1,class 2 faults and class 3 faults.

REQUIRED HARDWARE

Downloading of the ECB requires the following equipment:

Laptop computer or Personal Computer (PC) with at least3MB of free hard disc space, a modem and a Windows 95 orlater operating system.

A special interface cable is required to connect theComputer to the ECB. The interface cable (P/N AGE 70021)is available by contacting Hamilton Sundstrand.





U di l f thi d t i bj t t th






TROUBLESHOOTING

ECB TROUBLESHOOTING AID

To download and diagnose fault data, refer to APIC SIL APS32-

0049-47 for in-depth instructions.

Basic Steps:• Connect the interface cable from the computer to the ECB.• Power-up computer.• Select Diagnose on the tool bar.• Enter operators name on the Setup screen.• APU master switch ON (APU not running.)• Select Continue on the Setup screen.











TROUBLESHOOTING


ECB TROUBLESHOOTING AID (Fault Information)

The computer screen displays Class 1, Class 2 faults and Class 3faults. The screen will download and provide a file automatically forreview. (See example on page 13.6.)

Select the Most Recent scroll bar on the screen to scroll through thevarious faults.Each fault or fault combination is provided with a fault descriptionand recommended action.








jrestriction on the title page of this document.



TROUBLESHOOTING


REAL-TIME DATA MONITORING

With the Real-Time Data monitoring screen displayed, select AnalogI/O, Speed/Temp, or Discreet Inputs. Each selection displays ascreen that provides real time data. The data is viewed at the bottomof the screen when a data box is selected.

Note: The more data boxes selected the longer it takes for theinformation to appear. Select data that is related to thespecific fault for a faster response time.

BASIC STEPS:• Connect the interface cable from the computer to the ECB.• Power-up computer.• Start and run APU.• Select data box.• Select Start Monitoring.• Select Stop Monitoring after data has been taken.

Selecting Save Data at the bottom of the screen and selecting a filename allows the data to be saved. (See page 13.9 and example onpage 13.10.)





Use or disclosure of this data is subject to thet i ti th titl f thi d t






TROUBLESHOOTING


SNAPSHOT VIEW

BASIC STEPS:

• Select Snapshot with the APU operating• Select Analog Inputs.• Select Discrete Inputs.• Click on Take Snapshot. (This will provide one quick view

of data)










restriction on the title page of this document.restriction on the title page of this document.







HSPS CT/NOV. 2006 Page iHAMILTON SUNDSTRAND PROPRIETARY

APS 3200 Auxi liary Power Unit

Front Matter




p g

HSPS CT/NOV. 2006 Page iiHAMILTON SUNDSTRAND PROPRIETARY


TABLE OF CONTENTS

SUBJECT PAGE

Preface............................................................................................iii

Abbreviations ................................................................................. v

APU Leading Particulars ...............................................................viii

SUBJECT SECTION

Introduction...................................................................................... 1

Power Unit.......................................................................................2

Oil System....................................................................................... 3

Fuel System ....................................................................................4

Air System....................................................................................... 5

Control System................................................................................ 6

Indicating System............................................................................ 7

Starting System............................................................................... 8

Electrical System.............................................................................9

APU Installation.............................................................................10

Maintenance.................................................................................. 11

Fault Isolation................................................................................12

Troubleshooting............................................................................. 13



HSPS CT/ NOV. 2006 Page iiiHAMILTON SUNDSTRAND PROPRIETARY


PREFACE

GENERAL DESCRIPTION

The APS 3200 Auxiliary Power Unit Maintenance Training Course,

developed by the Customer Service Training Group of HamiltonSundstrand Power Systems, is designed to give the student anunderstanding of the various components of the Auxiliary Power Unit(APU) and their functions. This course also provides routinemaintenance and troubleshooting.

STUDENT WORKBOOK

This workbook is intended for the “limited” purpose of providing

component familiarization, general data, and support information forthis maintenance course.

This is an uncontrolled document and will not be updated or revisedon a regular basis. Specific values given in this document such asspeed, temperature, and pressure are provided for the purpose ofillustration and are not necessarily representative of the true valuesof the APS 3200 APU.

FAA AND AIRCRAFT MANUFACTURER APPROVEDPUBLICATIONS

The Airline is provided a variety of FAA and Aircraft Manufacturerapproved publications for the APS 3200 APU. These publicationsare:

Aircraft Flight Crew Manuals

Aircraft Maintenance Manuals

Engine and Component Maintenance Manuals

Service Bulletins

Chapter 49 of the aircraft maintenance manual presents detailed APU and LRU removal and installation procedures plus maintenanceand servicing techniques that can be accomplished at the flight-line.Careful study of Chapter 49 will add to the student's expertise introubleshooting and maintaining the Hamilton Sundstrand APS 3200

APU.



AIRCRAFT APPLICATIONS

The information presented in this course applies to the followingaircraft:

AIRBUS 318, 319, 320, 321

HSPS CT/NOV. 2006 Page ivHAMILTON SUNDSTRAND PROPRIETARY




HSPS CT/NOV. 2006 Page vHAMILTON SUNDSTRAND PROPRIETARY



The abbreviations/symbols shown below are used in this manual:

A/D Analog/Digital

A/C Aircraft

AC Alternating Current

ACARS Aircraft Communication Addressing and Reporting System

ACMS Aircraft Condition Monitoring System

ADIRU Air Data Inertial Reference Unit

AIDS Aircraft Integrated Data System

APIC Auxiliary Power International Corp.

APS Auxiliary Power System

APU Auxiliary Power Unit

ARINC Aeronautical Radio Inc.

ATA Air Transport Association

AVAIL APU Available

BATT Battery

BCV Bleed Control Valve

BITE Built-In Test Equipment

BMC Bleed Monitor Computer

CB Circuit Breaker

cc/h Cubic centimeters per hour

CFDS Centralized Fault Display System

CLR Clear

CMM Components Maintenance Manual

CPU Central Processor Unit

D/A Digital/Analog

DC Direct Current

ECAM Electronic Centralized Aircraft Monitoring

EC dB Decibel

B Electronic Control Box

ECS Environmental Control System

EGT Exhaust Gas Temperature

EMI Electro-Magnetic Interference

EPLD Erasable Programmable Logic Device

ETOPS Extended Twin Engine Operations

FADEC Full Authority Digital Electronic Controller

FAR Federal Airworthiness Regulation

FCU Fuel Control Unit

FET Field Effect Transistor

FOD Foreign Object Damage

ft Feet

FWD Forward

GBX Gearbox



HSPS CT/NOV. 2006 Page viHAMILTON SUNDSTRAND PROPRIETARY



GCU Generator Control Unit

GMT Greenwich Mean Time

GPH Gallons Per Hour

HOT High Oil TemperatureHP Horse PowerHSPS Hamilton Sundstrand Power System

Hz Hertz

ICAO International Civil Aviation Organization

ID Identification

IGV Inlet Guide Vane

IPC Illustrated Parts Catalogue

ISA International Standard Atmosphere

JAR Joint Airworthiness Requirement

kg Kilogram

kg/m Kilograms Per Minute

kg/s Kilograms Per Second

kHz Kilo Hertz

kPa Kilopascal

kPaa Kilopascals Absolute

kPad Kilopascals Differential

kPag Kilopascals Gauge

kW Kilo Watt

L Liter

l/h Liters Per Hour

lb Poundlbs/hr Pounds Per Hour

lbs/m Pounds Per Minutelbs/sec. Pounds Per Second

LC Load Compressor

LOP Low Oil Pressure

LP Low Pressure

LRU Line Replaceable UnitLVDT Linear Voltage Differential Transducer

m Meter

mA Milliampere

MAX Maximum

MCDU Multi-function Control and Display Unit

MES Main Engine Start

MHz Mega HertzP Qts Quarts

MIN Minimum

mm Millimeter

MMEL Master Minimum Equipment List

MTBF Mean Time Between Failure



HSPS CT/NOV. 2006 Page viiHAMILTON SUNDSTRAND PROPRIETARY



SIG Pounds Per Square Inch Gauge

MTBUR Mean Time Between Unscheduled Removals

mV MillivoltN Rotation Speed

NGV Nozzle Guide Vane

NVM Non MemoryVolatile VAC Volts, Alternating Current

OAP Outside Air Pressure

OAT Outside Air Temperature

OBRM On Board Replaceable Memory

P/N Part NumberPCD Pressure Compressor Discharge

PMG Permanent Magnet Generator

PS Power Section

PSIA Pounds Per Square Inch Absolute

PSID Pounds Per Square Inch Differential

RAM Random Access Memory

ROM Read Only MemoryRPM Revolutions Per Minute

RTD Resistive Temperature Device

S Seconds

S/N Serial Number

SSLC Single Shaft Load Compressor

STS Status

THR Threshold

TRU Transformer Rectifier Unit

TSO Technical Standard Order

US G US Gallon

VDC Volts, Direct Current

°C Degrees Celsius

°F Degrees Fahrenheit

> Is Greater Than< Is Less Than

± Plus or Minus

Ω Ohm

Δ Differential

% Percent



HSPS CT/ NOV. 2006 Page viiiHAMILTON SUNDSTRAND PROPRIETARY



WEIGHT 136 Kg (299 lbs) (dry)

OPERATING ALTITUDE -304.8 M to 11,887 M (-1,000 to 39,000 ft)

SEA LEVEL 15°C (59°F) STD DAY PERFORMANCE

OUTPUT SHAFT HORSEPOWER 399.7 Kw (536 HP)

ROTOR SPEED 100% (49,300 RPM)

ROTOR OVERSPEED (SHUTDOWN) 105% (51,765 RPM)

BACK UP OVERSPEED (SHUTDOWN) 107% (52,751 RPM)

ROTOR UNDERSPEED (SHUTDOWN) 95% (46,835 RPM)

BLEED AIRFLOW 1.8 kg/SEC (2.6 LBS/SEC)

BLEED AIR PRESSURE 290 kPag (42 PSIG)

FUEL CONSUMPTION 148 kg/HR (178 L/HR) [327 LB/HR (47 GAL/HR)]



HSPS CT/NOV. 2006 Page ixHAMILTON SUNDSTRAND PROPRIETARY



EXHAUST GAS TEMPERATURE (SHUTDOWN)

START % SPEED EXHAUST GAS TEMPERATURE

0% 427°C (800°F)

10% 788°C (1450°F)

20% 899°C (1650°F)

30% 899°C (1650°F)

50% 853°C (1567°F)

80% 788°C (1450°F)

100% 670°C (1238°F)

RUN % SPEED EXHAUST GAS TEMPERATURE

100% 722°C (1332°F)



HSPS CT/NOV. 2006 Page xHAMILTON SUNDSTRAND PROPRIETARY



GEARBOX SPEEDS Input 49,300 RPMGenerator 24,034 RPM (output)Fuel Control 10,129 RPM (output)

Starter 32,045 RPM (output)Cooling Fan 51,965 RPM (output)Oil Pump 4,137 RPM (output)

OIL PRESSURE 241 kPag (35 PSIG) (minimum)345-414 kPag (50-60 PSIG) (normal)

OIL CAPACITY 3.9 L (4.16 Qts) (add)5.4 L (5.72 Qts) (full)

OIL TEMPERATURE (SHUT DOWN) 135°C (275°F) Lubrication system185°C (365°F) AC Generator

APPROVED OIL SPECIFICATION:

MIL-PRF-7808

MIL-PRF-23699

CAUTION:

DO NOT MIX OR SUBSTITUTE OIL SPECIFICATIONS. USE ONLY ONE OF THE APPROVED OILS. IF THE OIL SUPPLY IS LOW AND THE OIL BEING USED IS NOT AVAILABLE, DRAIN THE OIL SUMP AND CHANGE THE OIL FILTER. SERVICE THEOIL SYSTEM WITH AN APPROVED OIL.



HSPS CT/NOV. 2006 Page xi




APPROVED FUELS

Fuel Type Specification Temperature Range

Jet A ATSM D1655 (NATO Code F-35) -35°C (-30°F) to +57°C (+135°F)

Jet A-1 ATSM D1655 (NATO Code F-35) -43°C (-45°F) to +57°C (+135°F)

Jet B ATSM D1655 (NATO Code F-45) -54°C (-65°F) to +57°C (+135°F)

JP-4 MIL-T-5624 (NATO Code F-40) -54°C (-65°F) to +57°C (+135°F)





HSPS CT/NOV. 2006 Page xii






.



SECTION 1

INTRODUCTION






APS 3200- GENERAL PRESENTATION

Function

The APS 3200 is designed to provide compressed air and electrical

power to the aircraft on the ground and in flight.

- Electrical power supply to aircraft systems

- Compressed air supply to aircraft systems:

• Environmental Control System (ECS)• Main Engine Start (MES)• Various systems...

Requirements

Regulations: - JAR part 25, change 13- FAR part 25

Certification: - JAR APU change 2

Main Components


- The Auxiliary Power Unit (APU)


- The aircraft systems (Pneumatic system, Electrical system, Controlpanels).

The APU is a single spool gas turbine engine which drives a loadcompressor and an AC generator.

The ECB is an electronic contro ller, FADEC type (Full AuthorityDigital Electronic Control).

Component Location

- The APU is installed in the tail section of the aircraft.

- The ECB is installed in the aft cargo compartment, right side,forward of the cargo door.

Control and Display

- On the overhead panel for APU operation and fire control

On the ECAM (Electronic Centralized Aircraft Monitoring) for APUparameters display

On the external panel, under the nose section, for APU emergency-shut-down




.

AUXILIARYPOWER UNIT

CONTROL ANDDISPLAY PANELS

ELECTRONICCONTROL BOX(AFT CARGOCOMPARTMENT)

AIRBUS AIRCRAFT




.



APS 3200 - DESCRIPTION (1)Power Unit

The APU consists of a gas turbine engine (Power Section) whichdrives:

- A load compressor

- And an AC generator (alternator) through a gearbox.

The APU is of modular design. It has three modules:

- The power section

-

The load compressor

- The gearbox.

A common air inlet supplies the load compressor, the cooling fan andthe power section.

Power Section

The power section is a single spool gas turbine engine whichconsists of:

- A centrifugal compressor

- A reverse flow combustor chamber

- A two stage axial flow turbine.

Load Compressor

The load compressor is a single stage centrifugal compressor drivendirectly by the power section. Variable inlet guide vanes are used for

airflow and exhaust gas temperature control.

Gearbox

The gearbox, also driven by the power section, is attached to theload compressor. The gearbox provides the drive at the correctspeed for the AC generator and the APU mechanically drivenaccessories.

Electronic Control Box

The ECB provides control and monitoring of the APU and is locatedin the aircraft rear cargo compartment.



.


COMBUSTOR


AC GENERATOR

GEARBOX

LOADCOMPRESSOR

IMPELLER

TURBINES




.




- The APU air inlet plenum is connected to the aircraft air intakesystem.

The APU air inlet plenum has a screen to protect the APU internalcomponents from foreign object damage.

- The cooling fan assembly is located at the top of the gearboxfront face.

- The starter motor drives the APU rotor assembly during starting.

The starter motor is located on the front face of the gearbox.

- The fuel control unit supplies and meters fuel to the APU. It islocated on the gearbox front face.

- The load compressor scroll houses the load compressorimpeller.

- The air inlet plenum delivers air to the impellers.

The air inlet plenum is located between the load compressor andthe power section.

- The ignition exciter supplies high energy electrical power to theignitor plugs.

The ignition exciter is mounted on the left side of the air inletplenum.

- The oil cooler transfers the heat of the lubricating oil to the coolingair supplied by the cooling fan assembly.

- The APU exhaust system delivers the APU exhaust gases to theaircraft exhaust pipe.






APS 3200 - DESCRIPTION (2)

AIR BYPASS

PLENUM

OIL COOLER

AIR INLETPLENUM

EXCITER

LOAD COMPRESSORSCROLL

APU AIRINLET

FUEL CONTROLUNIT

STARTERMOTOR





APS 3200 - DESCRIPTION (3)Identification of Components

- The gearbox provides the drive for the AC generator and theaccessories for APU operation.

The gearbox also provides the sump for the oil system.

- The AC generator that provides electrical power for the aircraftsystems.

- The cooling fan assembly for airflow through the oil cooler andventilation of the APU compartment.

The cooling fan assembly is located on the gearbox front face.

- The APU drain collector . The collector is installed on the rightside of the gearbox by two struts.

- The air- bleed system that includes a servo valve, an actuator,and a bleed control valve.

- The inlet guide vane system that includes a servo valve, anactuator, the inlet guide vanes and their control mechanism.

- The combustor housing that houses the combustor chamber.

- Main and pilot fuel injection system installed on the combustorhousing.



.


MAIN AND PILOTFUEL INJECTIONSYSTEM


INLETGUIDE VANE

ACTUATOR

BLEED CONTROLVALVE



APU DRAINCOLLECTOR

GEARBOX




.



Power section provides the shaft power to drive the loadcompressor and the gearbox.

Power is produced by transforming the energy contained in theambient air and the fuel through thermodynamic cycle: compression,combustion, expansion.

- Compression of the air in the single stage centrifugal compressor

- Combustion of the air-fuel mixture in the reverse flow combustorchamber

- Expansion of the burned gases across the two stage axial flowturbine to drive:

• The power section impeller

• The load compressor impeller

• The gearbox.

The load compressor supplies compressed air to the aircraftpneumatic system. The air is compressed by a single stagecentrifugal impeller and uses variable inlet guide vanes to control theair flow. The compressed air is delivered through a scroll to the bleedcontrol valve.

The gearbox provides the drive for the AC generator, andaccessories for APU operation.

The AC generator that provides electrical power for the aircraftsystems.

The Electronic Control Box receives various signals from theaircraft and the APU to operate and monitor the APU.

The electronic control box controls the following:

- Rotation speed (N) (fuel flow)

- Load compressor surge protection (bleed control valve)

- Exhaust Gas Temperature (EGT) (inlet guide vanes).





TO AIRCRAFT

TO APUEXHAUST

POWER SECTION



ECB

BLEED CONTROLVALVE

COMPRESSION COMBUSTION EXPANSION

GENERATOR

AMBIENT AIRCOMPRESSED AIRCOMBUSTIONEXHAUSTFUEL FLOWELECTRICAL SIGNALS

IGV ACTUATORFUEL CONTROL

EXHAUST

GEARBOX

LOAD COMPRESSOR










SECTION 2

POWER UNIT




.




Function

The APU provides compressed air and electrical power to the aircraft.

Location

The APU is installed in the aircraft tail section.

Type

Single spool gas turbine engine driving a load compressor and an ACgenerator.

Main Characteristics

Characteristics at Aero Design Point, installed APU (ISA, sea level) aregiven for information only:

- Total power ............................400 kW (536 HP)

- Specific fuel consumption .......0.372 kg/kW.h (0.61 Ib/HP.H)

- Fuel consumption ...................148 kg/HR (178 L/HR)................................................[327 LB/HR (47 GAL/HR)]

- Electrical power ......................132 kW (177 HP)

- Pneumatic power ...................252 kW (338 HP)

- Bleed air flow .........................1.2 kg/sec. (2.6 lbs/sec.)

- Bleed air pressure ..................390 kPa (42 PSI)

- Rotation speed .......................49 300 RPM

- Direction of rotation ................clockwise (view from the rear)

- APU dry weight ......................136 kg (299 lbs).Main Components

- Gearbox (with AC generator and APU accessory drive)

- Load compressor (centrifugal type provided with inlet guide vanes)

- Air inlet plenum (air intake and air dist ribution)

- Power section including:

• A centrifugal impeller

A reverse flow combustor chamber

• A two stage axial flow turbine.




LOADCOMPRESSOR

CENTRIFUGAL

COMPRESSOR



GEARBOX AIR INLET

PLENUM

TURBINES

AC GENERATOR

COMBUSTOR

CHAMBER

ECB



.




The first part of the description deals with the APU rotating assemblyand the second part will consider the modular design of the APU.

The following main components are considered in this description:gearbox, air intake plenum, load compressor and power section.

Gearbox

The gearbox located at the front of the APU provides the mechanicaldrive for the AC generator and the accessories required for the APUoperation. The oil sump is also part of the gearbox.

Load Compressor

The load compressor is driven by the power section and providescompressed air to the aircraft pneumatic system. It is a centrifugalimpeller that has variable inlet guide vanes to control the air flowoutput.

Air Inlet Plenum

The plenum is located between the load compressor and the power

section. The plenum directs the air supply to the power section, loadcompressor and the oil cooling system.

Power Section

The power section provides mechanical shaft power to drive the load

compressor and the gearbox.

The power section comprises:

- A single stage centrifugal impeller

- A reverse flow combustion chamber

- A two stage axial flow turbine

- An exhaust system.

The main rotor assembly is supported by two bearings: A ballbearing at the front of the load compressor, a roller bearing at therear of the turbine.



.


DRIVE TRAINFOR AC GENERATOR

AND APU ACCESSORIESCENTRIFUGALIMPELLER COMBUSTION

CHAMBERFRONTBEARING

EXHAUST



OILSUMP

CENTRIFUGALIMPELLER

AIR INLETPLENUM

TURBINES

REARBEARING

VARIABLEINLET GUIDEVANES



.



POWER UNIT – DESCRIPTION (2)

APU Rotating Assembly

The APU rotating assembly includes the following components:

- The load compressor impeller

- The inter shaft which connects the load compressor impeller to thepower section rotor assembly

- The compressor impeller of the power section

- The turbine wheels.

The tie-bolt secures the main components of the APU rotorassembly.

Bearings

The APU rotor assembly is supported by two bearings:

- Front ball bearing

- Rear roller bearing

Quill Shaft

The quill shaft is splined into the rotor shaft and provides themechanical connection between the APU rotor shaft and thegearbox.



.


POWER SECTIONIMPELLERLOAD COMPRESSOR

IMPELLER

FRONT BALLBEARING



QUILL

INTERSHAFTTIE

BOLT

SECURINGNUT

TURBINES

REAR ROLLERBEARING

SECURINGNUT

A320-457a



.




General

The power section produces mechanical shaft power for APU

operation.

This mechanical power is used to drive:

- The load compressor which supplies compressed air

- The AC generator which supplies electrical power

- Accessories required for the operation of the APU.

Power Section Operation

The air enters the power section through the aircraft air inlet and the APU plenum.

In the plenum, this air is divided into two flows; one for the loadcompressor and one for the power section.

The power section air is directed to the centrifugal impeller which

increases the air pressure.

The air is then admitted to the combustion chamber, mixed with thefuel and burned to provide a continuous combustion process. Thegases are expanded across the turbines that transforms the gasenergy into mechanical energy.

The gases are then expelled overboard through the aircraft exhaustsystem.

Load Compressor Operation

The load compressor is driven by the power section and produces airflow to the aircraft pneumatic systems.

Gearbox Operation

The gearbox is driven by the power section to operate the APUaccessories and the AC generator.

Electronic Control Box (ECB)

The ECB provides control and monitoring of the APU.



.



BLEEDCONTROLVALVE

COMPRESSED AIR TO EXHAUSTCOMPRESSED

AIR TO AIRCRAFT

AC GENERATOR

ECB AMBIENT AIRCOMPRESSED AIR

COMBUSTIONEXHAUST



A320-458a



.




GEARBOX - GENERAL

Location

The gearbox is located at the front of the load compressor scroll.

Main Features

- Modular design

- Mechanical efficiency: 0.98

- Weight: 17 kg (37.4 lbs)

- Oil sump

- Gearbox drive power: 148 kW (198 HP)

- AC generator drive power: 132 kW (177 HP)

- Accessories drive power: 16 kW (21 HP)

- Material for housing: Aluminum alloy.

Gearbox Front Face View

- Oil cooling fan drive pad

- AC generator drive pad

- Starter motor drive pad

- Fuel control unit drive pad

- Accessories (oil filters, oil level sensor, de-oiling valve...).

Gearbox Left Side View

- Oil sight glass

- Oil fill tube


- Speed sensor

- Gearbox mounting flange (attachment with the load compressorscroll)

- APU front left mount.



.



COOLING FAN

MOUNTINGFLANGE AC GENERATOR


GEARBOX - GENERAL

APU FRONTMOUNT

FWD

OIL FILLTUBE

OIL SIGHTGLASS

HIGH OIL TEMPERATURE

SPEEDSENSOR

DE-OILINGVALVE

OIL LEVELSENSOR

OILFILTERS

STARTER MOTOR

FUEL CONTROL

DE-OILING

VALVE

A320-459a



.




GEARBOX DESCRIPTIO (1)

This description considers the gears, the bearings and the drivepads.

Gears

The gearbox comprises of 8 spur type gears made of steel alloy. Thegear train provides the correct speeds for the APU driven units.

BearingsThe gears are supported by bearings: 6 roller bearings and 6 ballbearings.

AC Generator Drive

- Speed: 24034 RPM- Direction of rotation: Clockwise.

Intermediate Gear- Speed: 14349 RPM- Direction of rotation: Clockwise- Centrifugal air-oil separator.

Cooling Fan Drive

- Speed: 51965 RPM- Direction of rotation: Anti clockwise- PMG (Permanent Magnet Generator).

Starter Motor Drive- Speed: 32045 RPM- Direction of rotation: Anti clockwise- Starter clutch: Sprag type.

Fuel Pump Drive- Speed: 10129 RPM-Direction o f rotation: Clockwise.

Oil Pump Drives- Lubrication pump

• Speed: 4137 RPM• Direction of rotation: Clockwise.

Scavenge pumps• Speed: 4137 RPM

Direction of rotation: Anti clockwise.

Note: Direction of rotation by viewing the front of the gearbox.



.



-

FRONT VIEWCOOLING FANDRIVE(51965 RPM)

INTERMEDIATEGEAR(14349 RPM)

STARTER MOTORDRIVE(32045 RPM)

AC GENERATORDRIVE

(24034 RPM)



DRIVEGEAR(49300 RPM)

FUEL PUMPDRIVE(10129 RPM)

OIL PUMPDRIVES(4137 RPM)



.





Identification of Gearbox Components

- The gearbox housing which forms the oil sump and provides theaccessories for the oil system (oil filter, oil level sensor, magneticplug...).

The gearbox housing also provides the mounting pads for:

• The oil cooling fan

• The AC generator

• The starter motor

• The fuel control unit

The gearbox housing is attached to the load compressor scroll bya mounting flange.

- The APU front left and right mounts are located on the sides ofthe gearbox.

- The gearbox gear train which includes:

• The AC generator drive gear

• The intermediate gear, which also forms the air-oilseparator

• The starter motor drive gear

• The fuel control unit drive gear

• The oil pump drive gears.



.



INTERMEDIATEGEAR AC GENERATOR

DRIVE GEAR

STARTER MOTORDRIVE GEAR



DRIVE

GEAR

FUEL CONTROLUNIT DRIVEGEAR

OIL PUMPDRIVE GEARSGEARBOX GEAR TRAIN

A320-461a



.




GEARBOX - OPERATION

During Starting

The starter motor is electrically energized and provides the torque tocrank the gear train and the APU rotor assembly.

At self-sustaining speed, the electrical supply to the starter is de-energized and the starter is disengaged by the sprag clutch.

Normal Running Condit ion

The power section provides the mechanical power to drive the loadcompressor and the gearbox drive gear.

The drive gear meshes directly with the AC generator gear.

It also drives an intermediate gear which in turn drives the oil coolerfan gear, the starter motor gear and the fuel control unit and oil pumpgears





AC GENERATORDRIVE

COOLINGFAN GEAR

DRIVEGEAR INTERMEDIATE

GEAR

DRIVENGEAR

STARTERDRIVE GEAR

FUEL CONTROLUNIT DRIVE GEAR

DRIVEGEAR


GEARBOX - OPERATION

RUN OPERATIONOIL PUMPDRIVE GEARS

START OPERATION

A320-461a



.





Location

The inlet plenum is located between the load compressor and thepower section.

Main Features

- Acoustically treated part

- Shop replaceable unit

- Weight: approx. 7.5 kg (16.5 lbs).

Main Components

The plenum consists of two parts, upper and lower, which areconnected by quick disconnect latches.

The lower part interfaces with the aircraft air inlet system. The airinlet to the plenum is provided with a screen made of stainless steelthat protects the APU internal components from foreign objectdamage.

The upper part has an outlet for air supply to the oil cooling system(supply to the oil cooler fan).

Construction

The plenum is of sandwich construction with a structural envelope,Nomex and felt metal. The structural envelope and Nomex are fireproof.

Operation

In the plenum, the air is separated into two flows by the splitter.

- One for the power section: 2.2 kg/s (4.8 lbs/sec.)

- One for the load compressor and cooling fan: 1.2 kg/s (2.6

lbs/sec.).



.



COOLING FAN

AIR SUPPLY

QUICK DISCONNECTLATCHES



LOADCOMPRESSORIMPELLER SPLITTER SCREEN

AMBIENT AIR

COMPRESSED AIR

A320-463a



.





Identification of the Air Inlet Plenum Components

- The lower part of the air inlet plenum interfaces with the APU airinlet system. It has a screen to protect the APU internal


The lower part incorporates noise treatment and a splitter whichseparates the air into two flows. It also provides the support for thefollowing components:

• The ambient air pressure and temperature sensors

• The differential pressure sensor

• The low oil pressure switch

• The ignition exciter.

- The upper part of the air inlet plenum is also noise treated.

The upper part has an oval outlet to supply air to the oil coolingsystem

- The quick disconnect latches secure the upper part and lowerpart of the air inlet plenum.



.



PLENUMUPPER PART

SPLITTER



A320-464a

AIR INLET

HOUSING

PLENUM

LOWER PART

QUICKDISCONNECTLATCH

COOLING FAN

AIR SUPPLY

INLET

SCREENLOCATINGTAB



.





Location

The load compressor is installed between the gearbox and the powersection.

Type

High pressure centrifugal impeller provided with inlet guide vanes.

Main Features

- Air flow: 1.2 kg/s (2.6 lbs/sec.)

- Pressure ratio: 4:1

- Max outlet temperature: 232°C (450°F)

- Rotation speed: 49 300 RPM

- Direction of rotation: clockwise (viewed from the rear of the APU).

Main Components

- Rotating components (compressor shaft, impeller, bearing,bearing seals)

- Stationary components (air inlet housing, variable inlet guidevanes, impeller shroud, diffuser, and scroll).



.



BLEED CONTROLVALVE

COMPRESSED AIRTO AIRCRAFT




INLET GUIDEVANES

COMPRESSORIMPELLER

SCROLL


A320-465a



.





The first part of this description deals with the load compressorcomponents, the second part will consider the inlet guide vanescontrol mechanism and the third part the identification of all thecomponents.

Air Inlet Housing

The housing allows the passage of air to the load compressor andsupports the inlet guide vanes. It is made of aluminum alloy.

Compressor Impeller

The impeller is constructed of titanium alloy. The rear shaft of the

impeller is connected to the rotor intershaft using a curvic coupling.The front is supported by a ball bearing.

Compressor Shroud

The shroud houses the impeller and is constructed of steel alloy.

Compressor Diffuser

It consists of 19 cambered vanes made of steel alloy.

Scroll

The annular scroll provides the air outlet of the load compressor. It iscast aluminum.

The scroll housing provides passages for static air pressure to theload compressor discharge pressure sensor.

Bearing

A ball thrust bearing supports the front shaft of the load compressor.It is mounted in the load compressor housing.

Bearing Seals

Oil that is used to lubricate the front bearing is prevented fromentering the impeller area by a floating carbon seal and a labyrinthseal.



.



COMPRESSORDIFFUSERDRAINSQUEEZEFILM THRUST

WASHER



COMPRESSORSHROUD

INLET GUIDEVANE

A320-450a

COMPRESSORIMPELLER

BALLBEARING FLOATING

CARBONSEAL

LABYRINTHSEAL

AMBIENT AIRCOMPRESSD AIR



.





Identification of Load Compressor Components

- The IGV assembly includes the variable inlet guide vanes, therack and pinion mechanism and the air inlet housing

- The compressor shroud houses the impeller.

- The load compressor impeller has main blades and splitterblades. The impeller is connected at the rear to the inter shaft bycurvic-coupling. The impeller front shaft is supported by the frontbearing.

- The scroll provides the air outlet of the load compressor. The

scroll also houses the load compressor diffuser.

- The front bearing is a ball bearing that supports the impeller frontshaft

- The labyrinth seal is pressurized with compressed air from thepower section impeller.

- The front bearing nut retains the front bearing and forms the

phonic wheel of the speed sensing system

- The tie-bolt and the securing nut.



.



SCROLL

LABYRINTHSEAL



FRONTBEARING

FRONT BEARINGJOURNAL

TIEBOLTSECURING

NUT

FRONT BEARING NUT(PHONIC WHEEL)

INLET GUIDE

VANE ASSEMBLY

COMPRESSORSHROUD

LOAD COMPRESSORIMPELLER



.





Inlet Guide Vanes

The Inlet Guide Vanes (IGV) consist of 24 vanes, made of titaniumalloy and mounted in the inlet housing.

Each inlet guide vane has a sector gear.

There are five guide vanes with holes in them. Three are located atthe 6:30 position, one at the ten o’clock and one at the two o’clockposition. The holes allow a minimum amount of air flow to the loadcompressor to prevent surging when the guide vanes are closed andthe APU is operating.

Control Mechanism

The mechanism controls the position of the vanes. The completemechanism consists of:

- The actuator

- The control rod

- The rack and pinion mechanism that moves the vanes.

The Actuator

The actuator is hydraulically operated. It uses fuel pressure meteredby an electrical signal from the electronic control box.

The Control Rod

The control rod is mechanically operated by the actuator.

The control rod is connected between the actuator and the inletguide vane assembly.

The Inlet Guide Vane Assembly

The inlet guide vane assembly consists of 24 sector gears engagedinto a common ring gear.

The ring gear is connected to the inlet guide vane control rod.





ACTUATORROD HOUSING AIR INLET

HOUSING


INLET GUIDEVANE CONTROLROD

INLET GUIDEVANE

ASSEMBLY

RINGGEAR

IGVPOSITIONINDICATOR

INLET GUIDEVANE

SECTORGEAR

LOAD COMPRESSOR – DESCRIPTION (3)

A320-467A



.





Air Inlet

The ambient air enters the APU through the aircraft air inlet and the APU plenum.

The plenum air is separated into three flows:

- Air for the power section

- Air for the oil cooling system

- Air for the load compressor.

The air for the load compressor passes through the inlet guidevanes; the flow of air depends upon the position (the angle) of thevanes. The air is then directed to the blades of the compressorimpeller.

Compression

As the air enters the blades of the rotating compressor impeller theair velocity increases.

The air leaves the tip of the blades at high velocity and flows throughthe diffuser vanes where velocity is transformed into pressure.

Delivery

The compressed air then flows into the scroll and delivered to thepneumatic system through a bleed control valve.



.




COMPRESSED AIR TO AIRCRAFT

SCROLL



DIFFUSERVANE

COMPRESSORIMPELLER INLET GUIDE

VANES

A320-468a




.





Function

The power section provides the power to drive the load compressorand the gearbox.

Location

The power section forms the rear part of the APU.

Type

Single spool gas turbine engine.

Main Components

The main functional components are:

- Single stage centrifugal impeller

- Reverse flow combustion chamber

- Two stage axial flow turbine

- Exhaust.



.





TWO STAGE AXIAL FLOW

TURBINESSINGLE STAGECENTRIFUGALCOMPRESSOR

MAIN CHARACTERISTICS

POWER400 Kw (536 HP)

SPECIFIC FUEL CONSUMPTION0.372 kg/kW.h (0.61 lb/HP.H)

FUEL CONSUMPTION327 LB/HR (47GAL/HR)

ROTATION SPEED49300 RPM

AIR MASS FLOW2.2 kg/s (4.8 lbs/sec)

COMPRESSION RATIO8:1

EXHAUST

REVERSE FLOWCOMBUSTIONCHAMBER


A320-469a



.




Function

The impeller supplies the required amount of compressed air to thecombustor chamber.

Location

The impeller is located at the front of the power section.

Type

Single stage, high pressure, centrifugal flow impeller.

Main Features

• Compression ratio: 8:1

• Outlet air temperature: 350°C (662°F)

• Rotation speed: 49 300 RPM.

Main Components

- The impeller is made of titanium alloy. It has main blades andsplitter blades. The front and rear shaft are integral with the

impeller which is connected at the front to the inter shaft and at therear to the turbine shaft by curvic-couplings using a tie-bolt.

- The diffuser assembly is made of stainless steel. It has 19 radialvanes. The diffuser assembly is secured to the scroll with bolts.

The impeller shield is treated with an abradable material thatprovides a close tolerance clearance between the shield and theimpeller.

A containment shield for impeller containment is mounted on theoutside of the combustor housing.



.




COMPRESSOR

HOUSING

IMPELLERSHIELD

CURVIC

COUPLINGCURVICCOUPLING



INTER SHAFTMAIN BLADES

SPLITTER BLADES



.




Identification of Compressor Components

- The intermediate shaft is connected to the front of the loadcompressor impeller and to the rear of the power section

compressor impeller by curvic-couplings.

- The compressor housing houses the impeller and thecompressor shield.

The compressor housing is attached at the front to the air inlethousing and at the rear to the diffuser assembly and the combustorhousing.

- The impeller containment shield is mounted to the compressorhousing.

- The impeller has main blades and splitter blades. The impeller isconnected at the front to the intermediate shaft and at the rear tothe turbine by curvic-couplings.

- The diffuser is mounted to the impeller shield.



.





COMPRESSORHOUSING

IMPELLERCONTAINMENT

SHIELD

INTERMEDIATESHAFT

DIFFUSER

IMPELLER IMPELLERSHIELD

POWER SECTION – COMPRESSOR - SECTION

a320-471a



.




Function

The combustor chamber burns the air-fuel mixture and delivers theresulting gas to the turbine.

Location

The combustor chamber is located in the middle of the powersection.

Type

Reverse flow, annular combustor chamber.

Main Features

- Fuel air ratio: 1/45

- Turbine inlet temperature: 1020°C (1868°F).

Main Components

- The combustor housing is made of steel alloy. It houses thecombustor chamber. It also has bosses for the mounting of fuel

injectors (3 pilot fuel injectors and 6 main fuel injectors) andigniters. The lower part of the external housing is provided with acombustor chamber drain valve.

- The combustor chamber is used for the fuel air mixturecombustion. The combustor chamber and the elbow are made ofheat resistant alloy and is provided with air holes and tubes.

- The heat shield acts as a shield between the bend assembly and

the impeller and directs the combustor gases to the turbines.



.



AIRCOMBUSTORTUBESHOUSING

FUEL



INJECTOR

IGNITER

COMBUSTORCHAMBER

BEND ASSEMBLY

HEAT

SHIELDTURBINECONTAINMENTSHIELD

A320-472a



.



POWER SECTION - COMBUSTOR CHAMBER -DESCRIPTION

Identification of Combustor Chamber Components

- The combustor housing houses the combustor chamber. It alsohas bosses for the mounting of the fuel injectors, the igniter plugs

and the combustor chamber drain valve.

- The combustor chamber has holes and tubes that allows air usedfor combustion and cooling to enter the combustor chamber.

- The bend assembly guides the burned gases from the combustorchamber to the inlet of the first stage turbine nozzle guide vane.

- The heat shield protects the diffuser holder plate of the power

section impeller.

The heat shield is located between the bend assembly and thediffuser assembly.

- The combustor chamber drain valve is threaded into the bottomof the combustor housing, this allows unburned fuel to drainoverboard. The valve is closed by air pressure in the combustorhousing.



.




POWER SECTION - COMBUSTOR CHAMBER - DESCRIPTION

HEATSHIELD

BEND ASSEMBLY

FIRST STAGE

TURBINE NOZZLE

COMBUSTORCHAMBER

COMBUSTORCHAMBER DRAINVALVE

COMBUSTORHOUSING

COMBUSTOR AIR PRESSURE



.




Function

The turbine extracts the energy from the combustor gases to drivethe impeller, the load compressor and the gearbox.

Location

The turbine is located at the rear of the power section.

Type

2 stage, axial flow turbine.

Main Features

• Turbine inlet temperature: 1020°C (1868°F)

• Turbine outlet temperature: 614°C (1137°F)

• Rotation speed: 49300 RPM

• Direction of rotation: clockwise (viewed from the rear of the APU).

Main Components

The two stage axial flow turbine comprises of:

- The first stage nozzle guide vane (22 cooled vanes)

- The first stage turbine wheel (37 fir tree blades inserted into a disc)

- The second stage nozzle guide vane (26 vanes)

- The second stage turbine wheel (31 fir tree blades inserted into adisc).

The turbine wheels are coupled together by curvic-couplings andsecured by a tie-bolt.

A turbine containment shield is located around the turbine wheel.

The turbine rear shaft is supported by a roller bearing and islocated in the rear bearing housing.



.


FIRST STAGE SECOND STAGENOZZLE GUIDETURBINE WHEEL




VANE

CONTAINMENTSHIELD

SECOND STAGE

TURBINE WHEEL

CURVICCOUPLINGS

ROLLER TIEBEARING BOLT

A320-474a



.




Identification of Turbine Components

- The first stage nozzle guide vane has 22 vanes installed in frontof the first stage turbine wheel

- The first stage turbine wheel has 37 fir tree blades inserted into adisc and secured by blade locks.

The turbine wheel is connected to the rear of the power sectionimpeller and to the second stage turbine wheel by curvic-couplings

- The second stage nozzle guide vane has 26 vanes installed infront of the second stage turbine wheel

- The second stage turbine wheel has 31 fir tree blades insertedinto a disc and secured by blade locks. Vibration dampers arefitted between the blades.

The turbine wheel is connected to the first stage turbine wheel by acurvic coupling.

The rear of the second stage turbine wheel is supported by a rollerbearing

- The containment shield is located around the turbine wheels.

- The turbine housing is located between the containment shieldand the turbine.

The turbine housing is connected to the exhaust housing.




FIR TREEBLADES



BLADELOCKS

VIBRATIONDAMPER

FIRST STAGENOZZLE GUIDE

VANE

NOZZLE GUIDEVANE SUPPORT

FIRST STAGETURBINE WHEEL

CONTAINMENTSHIELD

TURBINEHOUSING

SECOND STAGENOZZLE GUIDEVANE

SECONDSTAGETURBINEWHEEL

A320-475a



.




Function

The exhaust directs the exhaust gases to the aircraft exhaust pipe.

Location

The exhaust diffuser is located inside the APU exhaust housing.

Type

One piece, annular exhaust pipe.

Main Components

The exhaust housing is constructed of stainless steel and provides apassage for the exhaust gases. The housing also contains the rearbearing and struts that house oil pipes to the rear bearing.



.


FLOATING CARBON SQUEEZESEAL FILM



STRUT

DISCHARGE AIR

REAR

BEARING

AIR BYPASSPLENUM

LABYRINTHSEAL

ROLLERBEARING

FLEXIBLECAGE

EXHAUSTHOUSING

A320-451a



.




Identification of Exhaust Components

- The exhaust housing consists of an outer housing and diffusercone supported by struts.

The inner cone houses the rear bearing assembly and the rearbearing oil pipes.

- The rear bearing housing:

• The rear bearing

• The rear end of the tie-bolt

• The securing nut.

The rear bearing housing has threaded bosses for the mounting ofthe rear bearing oil pipes.

- The rear bearing o il pipes:

• The rear bearing oil supply

• The rear bearing oil scavenge

• The rear bearing oil venting.

- The rear bearing is a roller bearing, it is located inside the rearbearing cage.

- The rear bearing labyrinth seal is installed on the rear shaft ofthe second stage turbine wheel.

The labyrinth seal is pressurized by compressed air from thepower section compressor.

- The air bypass plenum is installed on the exhaust housing and isprovided with a drain connected to the drain system.




AIR BYPASSPLENUM

REAR BEARINGHOUSING

REAR BEARINGVENT PIPE

SECURINGNUT

EXHAUST

HOUSING

LABYRINTH



SEAL

REAR BEARING OILSUPPLY PIPE

REAR BEARING

SCAVENGE PIPE

REAR BEARING

TIEBOLT

CAGE

A320-476a



.




The power section produces the shaft power through thethermodynamic cycle: compression, combustion, expansion andexhaust.

Compression

Ambient air is directed into the blades of the rotating impeller. The airthen flows through the divergent passages of the diffuser. (The airvelocity is transformed into pressure.)

Combustion

The compressed air is divided into two flows:

- A primary flow mixed with the fuel for combustion

- A secondary flow (dilution air) to cool the combustor and internalparts.

As a result of the continuous burning process, the pressuredecreases slightly whereas the velocity and the temperatureincrease.

Expansion

Expansion of the gases takes place across the two stages of theturbines, this transforms the gas energy into shaft power.

The gases flow through the nozzle guide vanes which increase thevelocity, then across the turbine blades. The aerodynamic forcescause the turbine wheels to rotate.

During expansion, the velocity of the gases increases and thepressure and temperature decrease.

Exhaust

The gases are then expelled overboard through the exhaust system.



.




AMBIENT AIR

COMPRESSED AIRCOMBUSTIONEXHAUSTFUEL

a320-477a

PRESSURE AND

TEMPERATUREVALUES ARE GIVEN

AT ZERO DESIGNPOINT FORINFORMATION



.




The power section provides air flow to pressurize the APU labyrinthseals, to cool internal heated parts and balance rotor forces.

Pressurization

- Pressurization of Labyrinth Seals

Labyrinth seals are supplied with air pressure. A pressuredifference across the seals provide a non contact seal.

- Pressurization of Load Compressor Front Bearing

The pressurized air, bled from the outlet of the power sectionimpeller, flows through an external pipe to the labyrinth seal of theload compressor front bearing and the cooling fan labyrinth seal.

- Pressurization of Power Section Rear Bearing

The pressurized air, bled at the outlet of the power sectionimpeller, flows through the power section rotor assembly to therear bearing labyrinth seal.

Cooling

To prevent excessive heating of the parts subjected to thecombustion gases, a circulation of cooling air (bled at the outlet of

the power section impeller) is provided through the power sectionrotor assembly, and is directed by internal passages to the turbinewheel faces.

Balance of Forces

The shaft, the turbine wheels, and the compressor impellers aresubjected to axial forces resulting from the operation of the rotorassembly.

To reduce the forces on the bearings, air pressure is used on thebackside of the power section impeller.




AXIAL THRUST

EXTERNAL PIPE TOLOAD LCOMPRESSORFRONT BEARING ANDCOOLING FANLABYRINTH SEALS

AMIENT AIRCOMPRESSED AIREXPELLED SEAL

AND COOLING AIR


POWER SECTION - OPERATION (2)a320-478a

FRONT BEARINGLABYRINTH SEAL

AIR

REAR BEARING LABYRINTHSEAL AIR



.


APS 3200 AUXILIART POWER UNIT






SECTION 3

OIL SYSTEM







Function

The system is used to lubricate and cool the APU and the ACgenerator.

Location

The system components are all located on the gearbox except the oilcooler. The cooler is located on the left side of the APU.

Main Features

Self contained, full flow system.

- Max oil temperature: 135°C (275°F)

- Normal oil pressure: 345 - 414 kPa (50 - 60 PSIG)

- Low oil pressure: 241 kPa (35 PSIG)

- Oil quantity: 5.4 liters (5.72 Qts) at FULL mark

Lubrication and Cooling Requirements

- The APU rear bearing

- The APU front bearing

- The gearbox gears and bearings

- The AC generator

- Cooling Fan




FRONTBEARING



REARBEARING

GEARBOXGEARS ANDBEARINGS

LUBRICATION AND

COOLING OF AC GENERATOR

OIL SYSTEMMAIN FEATURES

MAX OIL TEMPERATURE135 C (275 F)

NORMAL OIL PRESSURE

345 – 414 Kpa (50-60 PSIG)LOW OIL PRESSURE

241 KPa (35 PSIG)OIL QUANTITY

5.4 liters (5.72 Qts)

OIL SYSTEM COMPONENTS

ON GEARBOX(EXCPT OIL COOLER)







Oil Sump

The oil sump is formed by the lower part of the gearbox.

The gearbox has a fill tube for gravity filling, an overflow drain, apressure fill connector and a sight glass.

The gearbox intermediate gear also functions as the air/oil separatorand provides air venting of the gearbox.

Oil Pumps

One lubrication pump and two scavenge pumps are driven by the

gearbox.

The pressure system is provided with a pressure relief valve locatedon the front of the gearbox.

Oil Filters

There is one filter in the lubrication line and one in the AC generatorscavenge line.

Both filters are the same and each have a filter element impendingblockage switch indicator. They are mounted on the lower front faceof the gearbox. The oil filter by pass valve for each filter is located inthe gearbox and is non adjustable.

Oil Cooler

The oil cooler cools the oil and has a by-pass valve.

De-oili ng Valve

The de-oiling valve is a solenoid valve located at the inlet of thepressure pump. When energized open, the valve prevents oil flowthus reducing the APU starting loads on the starter.

Monitoring Devices



- AC generator high oil temperature sensor

- Oil level sensor

- Oil level sight glass

- Oil filter impending blockage switch indicator on each oil filterassembly

- Magnetic drain plug.






OIL SUMPOIL PRESSUREOIL RETURN

AIR-OIL MIST

SCAVENGEPUMPS

OIL FILTERBYPASS VALVES

OIL FILTERSOIL LEVELSIGHT GLASS

AC GENERATORHIGH OILTEMPERATURESENSOR

LOW OILPRESSURESWITCH

PRESSURERELIEF VALVE

CHECKVALVE

CHECK VALVE

OIL COOLER

AIR OIL

SEPERATOR

LUBRICATIONPUMP

DE-OILINGVALVE

OIL LEVELSENSOR

OILFILLERTUBE

MAGNETICDRAIN PLUG


a 320-481a





OIL SYSTEM – OPERATION

The main functions of the oil system are : oil supply, scavengereturn, venting and indicating.

Oil Supply

The lubrication pump draws the oil from the sump and delivers it tothe oil system. During starting, the de-oiling valve opens and air isdrawn into the pump to prevent oil flow. After de-oiling the oil flows tothe oil cooler, then to the filter.In the event oil flow through the filter becomes restricted, the switchindicator is activated. If the filter becomes blocked, the oil filterbypass valve will open and allow flow to the oil system.The oil pressure relief valve opens to regulate the oil systempressure. When the valve is open, some of the oil flow is bypassedback to the inlet side of the lubrication pump.

Scavenge Return

After lubrication, the oil returns to the gearbox sump by twoscavenge pumps:- One for the power section rear bearing that returns the oil directly

to the sump- One for the AC generator that returns the oil to the sump through a

filter.

Note: The front bearing and the gearbox are scavenged by gravity.

Scavenge Return

After lubrication, the oil returns to the gearbox sump by two

scavenge pumps:-One for the power section rear bearing that returns the oil directly to

the sumpOne for the AC generator that returns the oil to the sump through a

filter.Note: The front bearing and the gearbox are scavenged by gravity.

Venting

Oil mist in the gearbox is separated by a centrifugal air-oil separator.The gearbox is vented to the exhaust through an external pipe.

Monitoring-Low oil pressure switch-High oil temperature sensor- AC generator high oil temperature sensor- Oil filter impending blockage switch indicators- Oil level sensor

- Oil level sight glass- Magnetic drain plug



V



OIL SYSTEM - OPERATION

OIL SUPPLYOIL PRESSURESCAVENGE RETURN

VENTING

a 320-481 aOIL SYSTEM - OPERATION






Lubrication is required for the AC generator, the gearbox and the APU bearings.

AC Generator Lubricat ion and Cool ing

Oil Supply

From the lubrication pump and filter, the oil is supplied to the ACgenerator:

- One flow for cooling

- A second flow to lubricate the generator drive shaft splines.

Scavenge and Return

The oil from the AC generator is scavenged by a pump and returnedto the gearbox sump through a filter.

Gearbox Lubrication

Oil Supply

The oil flowing from the lubrication pump passes through the filterand then by means of internal lines and jets is sprayed onto thegears and bearings.

From the gearbox the oil is also supplied to the cooling fan bearingsand to the rotor assembly front bearing.

Scavenge and Return

After lubrication the oil returns to the gearbox sump by gravity.





ENGINE LUBRICATION (1) AC GENERATOR LUBRICATION

GEARBOX LUBRICATION

AC GENERATORLUBRICATION

AND COOLING

AC GENERATOROIL SCAVENGE



DE-OILED AIR TO

EXHAUST

DE-OILED

AIR TOEXHAUST

AC GENERATORDRIVE SHAFT SPLINELUBRICATION

SPRAYJETS

TO LUBRICATIONPUMP

TO LUBRICATIONPUMP

OIL RETURNTO SUMP

OIL SUPPLY

OIL PRESSURESCAVENGE RETURNVENTING

AC GENERATOR LUBRICATION

a 320-482 a






Front Bearing Lubrication

Oil Supply

The lubrication for the rotor front bearing is provided by pressurizedoil from the gearbox oil system.

A jet located in the gearbox housing sprays oil between the front endof the load compressor shaft and the front bearing nut. (PhonicWheel)

The oil runs along the shaft, lubricates the quill shaft splines andenters the gap through the split inner races to lubricate the bearing.

Oil flow to the bearing is also provided by oil passages between thegearbox and bearing outer race to provide a squeeze film to dampenbearing vibration.

Scavenge and Return

After lubrication the oil is returned to the sump by gravity.

Sealing

Oil sealing of this assembly is by a floating carbon seal and alabyrinth seal using air from the power section impeller.

A drain cavity between the seals is vented overboard, into the APUdrainmast.




FLOATING AIR FROMCARBONSEAL

POWER SECTIONIMPELLER

SQUEEZEFILM

BALL BEARING


ENGINE LUBRICATION (2) - FRONT BEARING LUBRICATION

INTERNAL OILSUPPLY

FRONT BEARINGNUT

DRAINCAVITY

LOADCOMPRESSORIMPELLER

LABYRINTHSEALS

a 320-452 a

OIL PRESSURE SPRAYCOMPRESSED AIRSEA L AIR VENT






Rear Bearing Lubr ication

Oil Supply

The lubrication of the rotor rear bearing is provided by pressurized oil

from the gearbox oil system.

The oil is supplied to the rear bearing through an external pipe.

In the bearing area, the oil is directed to the outer race to provide asqueeze film and an internal line that sprays oil into the rear tie-boltarea.

Drilled passages in the tie-bolt allow oil circulation for lubrication and

cooling of the roller bearing.

Scavenge and Return

After lubrication, the oil is scavenged back to the sump through anexternal pipe by a scavenge pump.

Sealing

Oil sealing in the bearing area is accomplished by a floating carbon

seal and a rotating labyrinth seal. The seals are pressurized with airflow from the power section impeller.




OIL SUPPLY

TIE

BOLT

SQUEEZEFILM



ENGINE LUBRICATION (3) - REAR BEARING LUBRICATION

a 320-453 a

ROTATINGLABYRINTH

SEAL

ROLLERBEARING

AIR FROMPOWER SECTIONIMPELLER

FLOATINGCARBONSEAL

OIL PRESSUREOIL RETURNCOMPRESSOR AIR





OIL SUMP

Function

The sump provides a reservoir for the APU lubrication system.

Location

The sump is located in the bottom of the gearbox.

Main Features

- Capacity at the "FULL" mark: 5.4 litters (5.72 Qts)

- Capacity at the "ADD" mark: 3.95 litters (4.16 Qts)

Main Components

The main components of the oil sump are:

- Oil filler tube

- Oil overflow boss

- Oil pressure fill port

- Air-oil separator

- Magnetic drain plug

- Pressure relief valve

- Oil level sensor

- Oil level sight glass.




GEARBOX

OIL FILLERTUBE

OILOVERFLOWBOSS


OIL SUMP

OIL LEVEL

SENSOR

MAGNETICDRAIN PLUG PRESSURE

RELIEF VALVE

OILPRESSUREFILL PORT

OILLEVELSIGHTGLASS

GEARBOX – LEFT SIDE VIEWGEARBOX – FRONT VIEW

a 320-483 a





AIR-OIL SEPARATOR

Function

The air-oil separator separates the oil from the air.

Location

The air-oil separator is located in the upper part of the gearbox.

Description

The air-oil separator is part of the gearbox intermediate gear.

The gear has a hollow shaft with radial drillings. The rear of thehollow shaft vents into a passage in the gearbox housing.

Operation

An air-oil mist is created in the gearbox when the APU is operating.

The oil is separated from the air by the rotating action of the gearboxintermediate gear. The oil returns to the gearbox sump by gravityand the air is vented through a pipe to the APU exhaust.





AIR-OIL SEPARATOR

INTERMEDIATEGEAR

AIR-OILSEPERATOR

OIL RETURNTO SUMP

OIL MISTDE-OILED

AIR

TO APUEXHAUST

OIL RETURNTO SUMP

AIR – OIL SEPERATOR





OIL PUMPS - GENERAL

Function

One pump is used for the lubrication supply and two pumps forscavenge.Location

The oil pumps are located inside the gearbox front face.Main Features- Lubrication pump

• Type: Vane type• Flow: 2160 l/h (570 GPH)

- AC generator scavenge pump• Type: Vane type pump• Flow: 2160 l/h (570 GPH)

- Rear bearing scavenge pump• Type: Gerotor type pump• Flow: 160 l/h (42 GPH)

OIL PUMPS - DESCRIPTION

Gerotor Type

The gerotor is a positive displacement pumping unit consisting of twoelements: an inner and outer rotor.The inner rotor has one less tooth than the outer, and has its

centerline positioned at a fixed eccentricity from the centerline of theouter element.The inner element is driven by the gearbox.Vane TypeThe vane type pump consisting of a slotted inner rotor equipped withvanes operating in an eccentric housing.Operation of the Pressure Relief ValveThe oil pressure relief valve is a non adjustable, spring loaded reliefvalve.The valve will open when oil pressure reaches 345-414 kPag (50-60PSIG). The oil that is bypassed, returns to the inlet of the lubricationpump.




AC GENERATORSCAVENGE PUMP

FUEL CONTROLUNIT DRIVE


OIL PUMPS - GENERAL - DESCRIPTION

OIL SCAVENGE

PUMPS

OIL PRESSUREPUMP PRESSURE

RELIEF VALVE

OIL PUMPDRIVE GEARS

REAR BEARINGSCAVENGEPUMP

LUBRICATIONPUMP

a 320-485 a





DE-OILING VALVEFunction

The de-oiling valve reduces the APU starting lead during startconditions.

Location

The valve is located on the left side of the gearbox.

Main Features

- Solenoid valve operated by the ECB

- Nominal rating: 28 VDC; 1.0 amps

- Solenoid valve energized open.

Description

The de-oiling valve is a solenoid operated valve directly controlled bythe ECB.

Operation

During the APU start up the de-oiling valve is energized open by theECB. When the valve is open the lubrication pump is prevented frompumping oil into the system. This reduces the starting load of the

APU and allows faster acceleration.

When the APU accelerates to 55% speed, the ECB de-energizes thede-oiling valve and allows the lubrication pump to produce oil flow.

During shutdown, the de-oiling valve is again energized by the ECBwhen the APU de-accelerates to 90% speed. This allows the oilremaining in the system to return to the oil sump with the exceptionof one quart remaining in the oil cooler.





DE-OILING SYSTEM

DE-OILING VALVE

AIR

GEARBOX LEFT SIDE

TOOIL

OIL SUMPCOOLER

OIL

FROM

TOLUBRICATION

PUMP

AIR

SUMPDE-OILING VALVE

a 320-486a

DE – OILING SYSTEM





OIL FILTERS - GENERAL

Function

The function of the oil filters is to filter the oil.

There are two filters: one for lubrication and one for the AC generator

scavenge. They are the same type of filter.

Location

The lubrication filter is located in the pressure line after the oil cooler.The scavenge filter is located after the AC generator scavengepump.

Both filters are installed at the bottom front face of the gearbox.

Main Features

- Filter element: 20 microns

- By-pass valve setting: 345-414 kPad (50-60 PSID)

- Switch indicator setting: 207-241 kPad (30-35 PSID).

OIL FILTERS - DESCRIPTION

Each filter system consists of:

- A 20 micron disposable cartridge

- An oil filter impending blockage switch indicator

- A by-pass valv




LUBRICATIONFILTER

SWITCHINDICATOR

AC GENERATORSCAVENGE FILTER


OIL FILTERS - GENERAL - DESCRIPTION

LUBRICATIONFILTER

a 320-487 a






Oil Flow

In normal operation the oil is filtered and then flows to the oil system.

Pre-blockage of the Oil Filters

Should the filter become contaminated, a difference in pressureacross the filter will occur.

Two switch indicators are mounted on the front of the gearbox neareach oil filter. The switch indicator provides a visual indication when

the oil temperature is 74°C (165°F) and the oil pressure across thefilter reaches 241 kPad (30-35 PSID). The ECB also monitors eachswitch indicator and will store the fault message.

By-pass

When the differential pressure across the filter exceeds 345 to 414kPad (50 to 60 PSID), the by-pass valve will open and allowunfiltered oil to flow into the system.

The by-pass valve is located in the gearbox and is non-adjustable.






a 320-488 a






OIL COOLER - GENERAL

Function

The oil cooler transfers the heat of the lubr icating oil to the airflowing through the cooler.

Location

The oil cooler is installed on the left side of the APU.

In the oil system, the cooler is located between the lubrication pumpand the filter.

Main Features

- Oil cooling ability: 2160 l/h (540 GPH)

- Oil cooler by-pass valve setting:

• Opening threshold: 207 kPad (30 PSID)

• Fully open: 345 kPad (50 PSID).

OIL COOLER - DESCRIPTION

The oil cooler is a rectangular unit which includes:

- An oil cooler housing which consists of an integrally brazedaluminum heat-exchanger with an aluminum core and a stainlesssteel housing.

- A check valve and a by-pass valve to regulate the oil flow andinternal pressure of the oil cooler.A drain plug to drain theoil cooler




OIL COOLER – GENERAL - DESRIPTION

a 320-489 a







Normal Operation

The oil delivered by the lubrication pump flows through the aluminumcooling tubes that are cooled by the cooling fan air flow.

The cooled oil then flows to the various APU lubrication points.

By-pass Operation

When the pressure exceeds 207 kPad (30 PSID), the bypass valveopens.

The oil flow by-passes the cooler to the lubrication system.

Check Valve Operation

The check valve is an oil pressure operated valve.

When the pressure in the oil system is low (de-oiling during start andshutdown), the check valve closes and prevents draining of the oilcooler into the sump.

The check valve traps approximately one quart of oil in the oil cooler

when the APU is not running.

Air Flow

The oil cooler uses the airflow from the cooling fan to remove heatfrom the oil. The heated air is then discharged overboard through an

air duct located in the left APU compartment service door.




COOLING AIRINLET

COOLING AIRINLET



OIL FLOW AIR FLOW

NORMALOPERATION

BY-PASS

OPERATION

CHECKVALVE

OILOUTLET

OILOUTLET

CHECKVALVE

OIL FLOWRESTRICTION

OIL

INLET

OIL

INLET

BY-PASSVALVE CLOSED

BY-PASSVALVE OPEN

a 320-490 a





MONITORING DEVICES - LOW OIL PRESSURE SWITCHGeneral

Function

The Low Oil Pressure (LOP) switch senses the pressuredownstream of the filter.

The LOP switch initiates automatic APU shut down when the oilpressure is too low.

Location

The LOP switch is mounted on the right side of the air inlet plenumor on the lower right side of the gearbox

Main Features

- LOP switch setting: 241 kPag (35 PSIG)

- Output signal to ECB: ground signal.

Interfaces

- The ECB



The LOP switch consists of a normally closed switch and is openwhen normal oil pressure is present.

The ECB does not check for oil pressure until the APU has reacheda speed of 100% (RTL) plus 10 seconds.

If oil pressure is below 241 kPag (35 PSIG), and the APU isoperating at 100% speed, the APU will shut down after running for10 seconds.




LOW OIL PRESSURE SWITCH

MONITORING DEVICES

a 320-491 a






MONITORING DEVICES - OIL TEMPERATURE SENSOR

General

Function

The Oil Temperature (HOT) sensor senses the temperature of the oilat the outlet of the oil cooler. When the oil temperature is too high,the HOT sensor initiates automatic APU shut down.

Location

The HOT sensor is installed on the lower rear face of the gearbox.

Main Features

- HOT sensor setting: 135° C (275° F)


- Sensor output signal (to ECB): variable output voltage

- 100 Ω RTD; 1 mA; 19°C to 149°C (67°F to 300°F.)

Interfaces

- The ECB



The HOT sensor is a Resistive Temperature Device (RTD) suppliedwith a constant current of 1 mA (by the ECB). The resistance varieswith the oil temperature and modifies the sensor output voltage.

When the oil temperature reaches a limit value of approximately135°C (275°F), the ECB will initiate automatic APU shut down.

Note: The AC generator also has an integral oil temperaturesensor which causes the APU to shut down when anexcessive temperature is detected (180°C; 365°F). Thesensor is monitored by the ECB.




ECB

TO AIRCRAFT

RESISTIVETEMPERATUREDEVICE(135C / 275F)


MONITORING DEVICE

a320-491 a

3 WAYSOLENOID VALVEGEARBOX LEFT SIDE

HOT SENSOR

OIL SUMP

OIL COOLEROIL FILTER

FROMOILCOOLER

TOOILFILTER

HOT SENSOR

OIL TEMPERATURE SENSOR





MONITORING DEVICES - OIL LEVEL SENSORGeneral

Function

The oil level sensor measures the quantity of oil in the gearboxsump.

When the oil level is too low, the sensor provides a flight deckwarning of low oil quantity on the lower ECAM, APU systems page.

Location

The oil level sensor is located on the right side of the gearbox.

Main Features


- Sensor output signal (to ECB): variable output voltage.

Interfaces

- The ECB



The oil level sensor is a Resistive Temperature Device (RTD) thatthe ECB supplies with a constant current of 75 mA.

The resistance varies with the oil level and changes the sensoroutput voltage sensed by the ECB.

At power up, the oil level is checked for a period of 8 seconds and isdetermined OK or LOW by the ECB.

If the oil level is low, the ECB will display "OIL QTY LOW" messageon the lower ECAM when the APU system page is selected.




MONITORING DEVICES

GEARBOX FRONT VIEW

a320-493a

OIL LEVEL SENSOR







GEARBOXLEFT SIDE

GEARBOXFRONT VIEW

OIL LEVEL SIGHT GLASS MAGNETIC DRAIN PLUG

OIL LEVEL SIGHT GLASS - MAGNETIC CHIP DETECTOR

a320-494aMONITORING DEVICES






OIL PIPES

External Pipes

Supply

- From lubrication pump, oil cooler and to the gearbox

- From gearbox to power section rear bearing.

Scavenge

- From power section rear bearing to scavenge pump.

Vent

- From power section rear bearing to air-oil separator

- From air-oil separator to APU exhaust system.





OIL PIPES

OIL PRESSUREOIL SCAVENGEVENT a320-495a

OIL PIPES










SECTION 4

FUEL SYSTEM


FUEL SYSTEM GENERAL






Function

The fuel system provides the supply and the control of fuel to the APU under all operating conditions.

Systems Involved

- The aircraft fuel system

- The pneumatic system

- The APU control system


APU Fuel System Main Components

- Fuel control unit

- Flow divider

- Pilot fuel manifold and injectors

- Main fuel manifold and injectors.

Components Location

- The fuel control unit is located on the front face of the gearbox

- The flow divider is located on the combustor housing

- The fuel manifolds and injectors are located on the combustorhousing.






FUEL SUPLYUN-METERED FUELMETERED FUELFUEL RETURN





The system consists of a fuel control unit, a flow divider and fuelmanifolds and injectors.

Fuel Control Unit

The fuel control unit contains the following injector components:

- Low fuel pressure switch (aircraft supplied)

- Low pressure pump (centrifugal type)

- Filter (filter element, by-pass valve and impending blockage ΔPindicator)

- High pressure pump (gear type pump);

- Servo valve (electrically operated valve that meters the fuel flow inresponse to signals from the electronic control box)

- Constant P valve (pressure differential valve that controls thedifferential pressure across the servo valve)

- 3 way solenoid valve (valve operated by the electronic controlbox to open and close the fuel supply to the fuel injectors).

- Pressure regulator (fuel pressure supply to the actuators of theair control system).

Flow Divider

The flow divider controls the flow to the main and pilot injectors. Thedivider also provides pilot purge to the exhaust.

Main Fuel Manifold and Injectors

- Manifold to supply fuel to the main injectors

- Main in jectors (six injectors mounted on the combustor housing).

Pilot Fuel Manifold and Injectors

- Manifold to supply fuel to the pilot injectors

- Pilot injectors (three injectors mounted on the combustorhousing).







INLET GUIDEVANE

ACTUATORFILTER

HIGHPRESSUREPUMP

SERVOVALVE

FLOWDIVIDER

PILOT FUELMANIFOLD

ANDINJECTORS

PRESSUREREGULATOR

PURGE TOEXHAUST

LOW FUELPRESSURE

SWITCH

MAIN FUELMANIFOLD

ANDINJECTORS

3 WAYSOLENOIDVALVE

LOW PRESSUREPUMP

DRAIN

FUELINLET

FUEL SUPPLYUN-MTERED FUELMETERED FUELFUEL RETURNFUEL DRAIN

CONSTANTDELTA-P VALVE a320-497a






( )Starting

When APU start is selected:

- The starter motor is energized and cranks the APU rotor assembly

- The ignition exciter operates and supplies high voltage spark to the

two igniter plugs

- The 3 way solenoid valve is energized open to provide fuel flow tothe injectors

- The servo valve is electrically operated to control the fuel flow.

Fuel from the aircraft fuel system is supplied by the low pressure andhigh pressure pumps through the servo valve and the 3 way solenoid

valve.

When the fuel pressure reaches approximately 138 kPad (20 PSID),the flow divider delivers fuel to the pilot injectors. The fuel injectedinto the combustor is ignited by the ignitor plugs.

When the fuel pressure reaches approximately 1380 kPad (200PSID), the flow divider delivers fuel to the main injectors.

During starting, the fuel flow is controlled by the servo valve usingsignals from the ECB.

At self-sustaining speed, the starter and the ignition system aredeactivated and the APU accelerates to 100% speed.

The APU is maintained at 100% speed under all load conditions bythe servo valve controlling fuel flow.






STARTING

IGNITION EXCITER ANDIGNITERS OPERATION

TO PILOT INJECTORS

TO MAIN INJECTORS

BY SERVO VALVECONTROLLED BY ECB

FUEL SUPPLY UN-METERED FUELMETERED FUELFUEL RETURNFUEL DRAIN

a320-498 a

STARTING






Running Condition

- Stabilized condition

The fuel control unit provides a flow higher than APU fuel flowrequirements. The fuel is metered by the servo valve and iscontrolled by the ECB. The excess fuel is returned to the HP pump

inlet through the constant AP valve and the fuel filter.

- Transient condition

When the load applied to the power section changes, the rotationspeed changes. The ECB senses the change and implements asignal to the servo valve. The fuel flow is metered to keep the rotorspeed constant.

Shut-down

When APU shut-down is initiated (manual or automatic), the ECB de-energizes the 3 way solenoid valve. Fuel flow to the fuel injectors isshut off and bypassed back into the fuel system.

One second later the ECB de-energizes the fuel servo valve.

Any fuel remaining in the pilot manifold assembly and fuel injectors ispurged into the exhaust by combustor air pressure.




FUELSUPPLYUN-METERED FUELMETERED FUEL


a320-499a








Function

The fuel control unit (FCU) supplies and meters fuel to the APU.

The fuel control unit also supplies regulated fuel pressure to the inletguide vane and bleed control valve actuators.

Location

The fuel control unit is mounted on the front face of the gearbox by av-band clamp.

Interfaces

- Aircraft fuel system

- Pneumatic system actuators

- Drain system

- Control system.

Main Features

- Fuel supply by a low pressure pump and a high pressure pump

- Fuel filtering for the high pressure pump.

- Fuel metering by an electronic system (servo valve and electroniccontrol box).

Main Components

- Fuel pumps

- Filter

- Servo valve


- Pressure regulator.




FUEL FILTER



SERVO VALVE


FUEL DRAIN a320-500A






Components of the Fuel Control Unit

- A low fuel pressure switch located at the FCU fuel inlet (notshown)

- Fuel Pumps

• A low pressure pump (centrifugal type)

• A high pressure pump (gear type) provided with apressure relief valve

- A drain line for the pump shaft seal

- A filter which includes a filter element, a by-pass valve and an

impending blockage AP indicator

- A servo valve (electrically operated valve that meters fuel flow inresponse to signals from the electronic control box)

- A constant P valve (a valve that controls the differential pressureacross the servo valve)

- A 3 way solenoid valve (valve operated by the electronic control

box to open and close fuel flow to the fuel injectors)

- A pressure regulator that provides a constant pressure to the airsystem actuators:

• A fuel outlet port (fuel supply to the actuators)

• A fuel return port (fuel return from the actuators)

- A fuel inlet union (connected to the aircraft fuel system)

- An electrical connector (current signals from the electroniccontrol box to the 3 way solenoid valve and the servo valve).

O-rings

Two O-rings are located on the fuel control. One on the fuel controlmounting flange and one on the drive shaft. Both O-rings must beproperly installed or excessive loss of oil will occur when the APU isoperating.




a320-501a








Low Pressure Fuel Pump

The low pressure fuel pump provides a positive supply to the inlet ofthe high pressure pump.

The pump is mechanically driven at the same speed as the high

pressure pump by a splined shaft (driven by the gearbox).

The splined shaft is provided with a seal and a drain line to the drainsystem.

Main Features

- Type: centrifugal



- Flow: 182 kg/h (400 lbs/hr) at 550 kPad (80 PSID).

High Pressure Fuel Pump

The high pressure fuel pump supplies a fuel flow higher than the APU requirements. The excess fuel is returned to the pump inlet

through the constant ΔP valve. The pump is also provided with apressure relief valve.

Main Features

- Type: gear type



- Flow: 727 kg/h (1600 lbs/hr)

- Relief valve setting: > 4480 kPad (> 650 PSID).

Note: - Fuel flow at 7 % N: 20 kg/h (45 lbs/hr)- Fuel pressure at 7 % N: 1379 kPad (200 PSID).




FUEL SUPPLY

UN-METERED FUEL METERED FUELFUEL RETURNFUEL DRAIN

a320-502a








Fuel Filter

The filter is located at the outlet of the low pressure pump.

The filter includes the following components:

- A filter element to filter the fuel

Filter specification: 10 microns

- An impending blockage P indicator to provide a visual warningof a restricted filter

Setting: 48 kPad (7 PSID)

- A by-pass valve to allow the fuel supply in the event of filterblockage

Setting: 324 kPad (46 + - 4 PSID).

O-ring

An O-ring is located inside the fuel filter cavity of the fuel control unit.The O-ring functions as a seal and a securing device for the filter

bowel. The bowel is not secured by any external locking device.





a320-503a




S V l 3 W S l id V l





Servo Valve

The servo valve meters the fuel during starting and normal operatingconditions.

The valve consists of a torque motor which operates a fuel metering

valve (clevis type).

The motor is electrically controlled by the ECB. ECB currentoperates the valve to meter fuel flow.

During starting, the servo valve meters fuel flow to accelerate the APU.

In normal operating conditions, the fuel flow is metered to maintain a

constant 100% speed.

The main features of the servo valve are:

- Type: Torque motor

- Current: 0 - 100 mA

- Metered flow: 6 - 198 kg/h (13 - 435 lbs/hr).

3 Way Soleno id Valve

The valve opens and closes the fuel supply for operation and shutdown of the APU.

The solenoid valve is energized open to supply fuel to the fuel

injectors (control from ECB).

When de-energized, a spring moves the valve to the close position.

When the valve closes, the fuel is shut off to the injectors andbypassed back into the fuel system.

During a normal or auto shutdown of the APU the ECB de-energizesthe 3 way solenoid valve, one second later the servo valve is de-

energized.

In the event the 3 way solenoid valve does not close, the APU willshut down when the servo valve is de-energized. If this conditionoccurs, the ECB will store a fault message. (APU FUEL VALVEFAILED OPEN).




UN-METERED FUELMETERED FUEL a320-504a




Constant P Valve Pressure Regulator





Constant P Valve

The valve maintains a constant pressure differential across the servovalve.

The valve senses upstream pressure on one side and downstream

pressure plus the force of a spring on the other side. The valveposition determines the amount of fuel to be returned to the fuelsystem.

The ΔP setting of the constant ΔP valve is of 689 kPad (100 PSID)across the servo valve. The valve is non-adjustable.

Pressure Regulator

The pressure regulator provides the fuel pressure supply to the inletguide vane actuator and the bleed control valve actuator. The valveis non adjustable.

The pressure regulator is closed from 0 to 60% APU speed. Whenthe speed is above 60%, the regulator will open and deliver 1724KPad (250 PSID) of fuel pressure to the actuators.




REGULATEDPRESSURE TO

ACTUATORS

REFERENCEPRESSURE FROM

LOW PRESSUREPUMP OUTLET

FUEL RETURNTO LOW

PRESSUREPUMP INLET

PRESSUREFROM HIGHPRESSURE PUMP


a320-505a




Function Interfaces





Function

The flow divider distributes fuel from the fuel control unit to the pilotand main injectors. It also provides purging of the pilot injectorsduring APU shut-down.

Location

The flow divider is installed on the left side of the combustor housing.

The flow divider is located downstream of the 3 way solenoid valve.

Main Components

The flow divider consists of two valves:

- A pilot injector and purge valve set at approximately 138 kPad (20PSID) to open.

- A main injector valve set at approximately 1380 kPad (200 PSID)to open.

Interfaces

- Fuel control unit

- Main injector manifold

- Pilot injector manifold

- Exhaust system (purge).

FUELCONTROL







UNIT

UN-METERED FUELMETERED FUELFUEL RETURNFUEL PURGE

a320-506a


Description Operating






The flow divider consists of:

- Two valves:

• A pilot injector and purge valve set at approx. 138 kPad(20 PSID)

• A main injector valve set at approx. 1380 kPad (200 PSID)

- A filter screen (located at the fuel inlet)

- Fuel inlet/outlet ports:

• Fuel inlet from the fuel control unit

• Fuel outlet to the pilot manifold

• Fuel outlet to the main manifold

• Fuel outlet to the exhaust system (purge).

- Starting

When the APU is started, the fuel pressure increases to 138 kPad(20 PSID). The pilot injector valve opens and allows fuel flow to the

pilot injectors.

When the pressure reaches 1380 kPad (200 PSID), the maininjector valve opens allowing fuel flow to the main injectors.

- Normal Running Condition

The two valves remain open to allow fuel flow to the pilot injectorsand the main injectors.

- Shut-down

As the fuel pressure decreases, the two valves close. The fuelremaining in the pilot injectors is purged into the exhaust bycombustor air pressure. At this time, a momentary puff of smokemay be viewed coming from the APU exhaust. This is a normaloccurrence.







METERED FUELFUEL PURGE


Function






The pilot manifold delivers fuel from the flow divider to the pilotinjectors during start and normal operation.

It also supplies the pilot fuel injectors with fuel during normal running.

Location

The pilot manifold is mounted around the combustor housing.

Description

The pilot manifold consists of flexible pipes connecting the flowdivider to the three pilot injectors. It is comprised of teflon tubes

encased in a single layer of steel braid that is covered with a rubbersheath.




FUEL SUPPLYUN METERED FUELMETERED FUELFUEL RETURN

a320-508a





Type Description






Simple jet injectors.

Location

The three pilot injectors are installed on the rear of the combustorhousing:

- One at the top (at 12 o'clock)

- Two at the bottom (one at 4 o'clock and one at 8 o'clock)

A simple jet injector comprises:

- A pilot injector body and mounting flange

- A fuel nozzle

- A heat shield

The injector fits into a heat shield that is provided with two air inletholes for cooling.

A gasket between the injector and the combustor housing.

Operation

A continuous flow of fuel is delivered to the combustor by the pilotinjectors and atomized by the fuel nozzles, the fuel is then mixedwith combustor air to maintain the combustion process.

METERED FUEL

INLET







COMBUSTOR HOUSINGREAR FACE

GASKET

PILOT FUELINJECTOR

a320-509aMETERED FUELCOMBUSTOR AIRCOMBUSTION


Function






The main manifold delivers fuel from the flow divider to the maininjectors.

Location

The main manifold is mounted around the combustor housing.

Description

The main manifold consists of flexible pipes connecting the flowdivider to the six main injectors. It is comprised of teflon tubesencased in a single layer of steel braid that is covered with a rubbersheath.





a320-510a




MAIN FUEL INJECTORS

Type Operation






Air blast injectors.

Location

The six main injectors are located on the combustor housing.

Description

An air blast injector comprises:

- A main injector body and mounting flange

- A fuel injection tube and a shrouded air passage

- A gasket between the injector and the combustor housing.

A continuous flow of fuel is delivered to the combustor by the maininjectors. The fuel is atomized by combustor air flowing through theshrouded air passage. The fuel is then mixed with combustor air tomaintain the combustion process.




MAIN INJJECTOR

BODY



MAIN FUEL INJECTORS

FUEL INJECTOR

TUBE

GASKET

COMBUSTION SWIRL FLOWMETERED FUELCOMBUSTOR AIRCOMBUSTION

a320-511a

FUEL PIPES

Fuel supp ly

From the aircraft f el s stem to the f el control nit

Fuel drain (pipe located on the APU left side)

From the flo di ider to the e ha st s stem






- From the aircraft fuel system to the fuel control unit.

Fuel distribution (pipes located on the APU left side)

- From the fuel control unit to the flow divider

- From the fuel flow divider to:

• The pilot manifold and injectors

• The main manifold and injectors

Fuel distribution (pipes located on the APU right side)

- From the pressure regulator of the fuel control unit to:

• The BCV servo valve (fuel supply and return)

• The IGV servo valve (fuel supply and return).

- From the flow divider to the exhaust system.

Fuel drain (pipes located on the APU right side)

- From the fuel control unit to the APU drain collector

- From the BCV actuator seals to the APU drain collector

- From the IGV actuator seals to the APU drain collector

- From the combustor housing, air bypass plenum and exhaust pipeto the APU drain collector.






FUEL PIPES

FUEL FLOW

DIVIDER



The APU fuel system has several interfaces: aircraft fuel system,pneumatic fuel system, APU control system, APU drain system.






Aircraf t Fuel Sys tem

The APU is supplied with fuel normally from the aircraft left wingtank. The aircraft low pressure fuel pump provides fuel to the APUwhen the aircraft tank pumps are not operating.

The low pressure valve is controlled by the ECB and is open whenthe APU is operating. The valve is closed when the APU is shutdown normally or by the APU fire switch.




FUEL SUPPLY

REGULATED FUELFUEL DRAIN

a320-513a





The aircraft fuel system supplies fuel to the main engines and APU.

The aircraft fuel system has three main tanks:

A low fuel pressure warning switch is located at the fuel inlet to thefuel inlet to the fuel control unit. The switch sends a signal to theECB if fuel pressure is too low.






y

- A left tank located inside the left wing


- A right tank located inside the right wing.

Each tank has electric pumps to supply the engines.

A cross feed valve, located between the tanks, connects the leftand right engine supply lines. In normal operation, the cross feedvalve is closed.

The low pressure valve isolates the APU from the fuel supply.

The valve is open when the APU is running. It closes when the APUis shutdown or when the FIRE switch is activated.

The APU low pressure fuel pump is controlled by a pressure switchlocated in the fuel line to the APU. The switch senses fuel tank pumppressure. If the pressure is too low or the fuel tank pumps are turnedoff, the switch will cause the APU low pressure fuel pump to turn on.

p

The ECB will display "FUEL LO PR" message on the lower ECAMwhen the APU system page is selected. This requires the APU to beabove 7% speed and the fuel pressure below 109 KPag (15.8 PSIG).




APU LOW PRESSURE

FUEL PUMP

a320-514a

LOW FUEL PRESSURE

WARNING SWITCH







APS 32OO AUXILIARY POWER UNIT



.




APS 3200


SECTION 5

AIR SYSTEM




Function

The air system provides compressed air to the aircraft on the groundand in flight

Component Location

The inlet guide vane system components are located on the rightupper side of the air inlet housing. The inlet guide vanes are






and in flight.

Main Features

- Flow: 1.2 kg/s (2.6 lbs/sec.)

- Pressure: 289.6 kPag (42 PSIG)

- Temperature: 232°C (450°F).

Main Components

Two systems are considered:

- The inlet guide vane (IGV) system controls the load compressorairflow and prevents EGT overtemperature of the power sectionduring load compressor operation. The inlet guide vanes arecontrolled by the ECB, servo valve, and the IGV actuator.

- The air bleed system delivers airflow from the load compressor tothe aircraft pneumatic system through a bleed control valve (BCV).The valve also functions as an anti-surge valve for the load

compressor. The BCV is controlled by the ECB, servo valve, andthe BCV actuator.

upper side of the air inlet housing. The inlet guide vanes arelocated in the air inlet housing ahead of the load compressor air inlet.

The air bleed system components are located on the right lower

side of the load compressor scroll outlet.

All the sensors are located on the APU.

Interfaces

- The ECB

- The aircraft pneumatic system


.







AMBIENT AIR

COMPRESSED AIRREGULATED FUELFUEL RETURN


Control of the System

The ECB uses various control signals from the aircraft and the APU






gsensors to control the inlet guide vanes and the bleed control valve.

Indication

The pressure is indicated on the lower ECAM APU system pagedisplay. The pressure is indicated by the load compressor dischargepressure sensor and transmitted to the indicator through the ECB,the ADIRU, the BMC computers in PSIG.

Air Sys tem Operation

The air system operation chart shows IGV and positions during

various modes of operation

.




ENGINE BLEED PACK MODE AIRCRAFT IGV BCVSPEED SWITCH MODEL POSITION POSITION

%

0 - ALL CLOSED DISCHARGE72º ( 0)

100 OFF CLOSED - ALL CLOSED DISCHARGE82º ( 0)

100 ON OPEN - ALL OPEN DELIVERY 48º 45º TO 90º

100 ON OPEN ECS A318 OPEN DELIVERY A319 48º TO -30º 90º

A320

100 ON OPEN ECS A321 OPEN DELIVERY48º TO -10º 90º

100 ON CLOSED MES ALL OPEN DELIVERY-5º 90º

OPERATION CHART





Function

The inlet guide vane system controls the load compressor air flow to

Interfaces-Fuel inlet (fuel pressure)






provide the required flow to the aircraft pneumatic systems.

Main Features


Components Involved

- The electronic control box (ECB)

- The inlet guide vane (IGV) system components: servo valve,

actuator, control mechanism and inlet guide vanes

Components Location

- The servo-valve and actuator form an assembly located on theright upper part of the APU on the air inlet housing.

- The inlet guide vanes and their control mechanism are located inthe air inlet housing.

Fuel outlet (fuel return)

- Fuel drain


- Position signal from the LVDT (Linear Voltage DifferentialTransducer) to the ECB

- EGT signal from APU exhaust thermocouples to the ECB.




REGULATED FUELFUEL RETURNFUEL DRAIN





The system includes the actuator, the control rod and the IGVmechanism.

IGV Actuator






Hydraulically operated actuator using fuel supplied by the FCU, itcomprises of a servo valve and an operating piston.

Control Rod

The rod connects the actuator piston to the IGV assembly. It isconnected to the actuator piston by a quick release pin.

IGV Position Indicator

The actuator rod housing has a position indicator cast on the top and

bottom of the housing. The indicator markings range from CLOSEDto OPEN. An external metal tab is attached to the control rod andfunctions as a position indicator for the IGV’s and used to manuallymove the IGV’s when the APU is not running. The igv’s should be inthe CLOSED position before starting the APU.

IGV POSITION

INDICATOROPEN




OPEN

ACTUATOR

ROD HOUSING

METAL TAB

CLOSED

a 320-516.1





Servo Valve

The servo valve controls the position of the actuator piston by usinga spill valve that meters the potentiometric jet. The servo valve has ametered fuel pressure inlet from the actuator and a return outlet to

IGV Contro l Mechanism and Inlet Guide Vanes

The inlet guide vanes are part of the IGV assembly. A sector gear isattached to each inlet guide vane and is driven by a common ringgear





metered fuel pressure inlet from the actuator and a return outlet tothe fuel control unit. The control current (0-100 MA) to the servovalve is provided by the ECB.

Actuator


The position of the actuator piston is provided by a Linear VoltageDifferential Transducer (LVDT). The position signal is sent to the

ECB for control of the servo valve.

gear.




METRED

FUEL PRESSURE

FUEL PRESSUREMETERED FUEL PRESSUREFUEL RETURN

FUEL DRAIN





The ECB provides a control signal (0-100 MA) to the servo valve byusing the following input signals.

APU Star ting

During start, the inlet guide vanes are in the closed position toreduce the APU starting loads. The inlet guide vanes are also in theclosed position during APU shutdown.





- APU bleed switch

- Speed (100%)

- EGT

- Air inlet pressure and temperature

- ECS mode

- MES mode.


When the actuator moves, the linear voltage differential transducer(LVDT) sends the actuator position signal back to the ECB.


The actuator piston positions the IGV assembly to control the airflowdelivery of the load compressor.

closed position during APU shutdown.

Operation

During load compressor operation, the position of the guide vanesare controlled by aircraft ECS computer signals sent to the ECB.

In the event APU exhaust gas temperature is too high during loadcompressor operation the ECB will signal the IGV actuator to reduceairflow delivery of the load compressor.

If inlet guide vane control is faulty, the IGV actuator will automatically

position the guide vanes to the closed position.

.

AIR INLETPRESSURE ANDTEMPERATURE




NOTE:

SEE OPERATIONCHART PAGE 5.4 FOR

AIRCRAFT MODEL AND IGV POSITIONS

FUEL PRESSUREMETERED FUEL PRESSURE




AIR BLEED SYSTEM - GENERALFunction

The air bleed system provides air delivery to the aircraft pneumaticsystem while preventing load compressor surge.

Main Features

Component Location

- The servo-valve, the actuator and the bleed control valve form acomplete assembly located on the right lower part of the auxiliarypower unit at the scroll outlet

T l d di h i





- Hydraulically operated actuator, controlled by a servo-valve and

the electronic control box.

Components Involved


- The Bleed Control Valve (BCV): servo-valve, actuator and valve

- Pressure sensors

- Ducts.

- Two load compressor discharge pressure pipes:

• One located in the scroll outlet (high pressure)

• One located in the diffuser of the load compressor (lowpressure)

Both are connected to the load compressor dischargepressure sensor to prevent load compressor surge.

Interfaces

- Fuel inlet

- Fuel outlet

- Fuel drain


- Position signal from the LVDT to the ECB

- Pressure signals to the load compressor discharge pressuresensor.




REGULATED FUELRETURN FUELFUEL DRAIN

AIR BLEED SYSTEM - GENERAL



The air bleed supply is controlled by a bleed control valve.

This valve comprises of a housing, a butterfly valve and an actuator.

APU Bleed Switch

APU Bleed Switch






When the APU master switch is selected to off during bleed air

operation, the APU will continue to run in a cool down mode for amaximum time of 2 minutes.

Housing

The housing is mounted on the load compressor scroll outlet bymeans of a v-band clamp.

Butterfly Valve

The valve is located in the BCV housing and directs air flow from theload compressor to the aircraft pneumatic systems, APU exhaust orboth.

The butterfly shaft extends through the top of the BCV housing. Theshaft has a slot machined into it that provides manual positioning ofthe valve and also serves as a valve position indicator.

The cooldown time limit can vary from 0 to 2 minutes. The time limit

depends on when the APU bleed switch is turned off prior toselecting the APU master switch to OFF.

Low B leed Air Pressure

In the event low bleed air pressure occurs, cycle the APU bleedswitch OFF and then to ON. This may restore the system to normal.







Servo Valve

The servo valve controls the position of the actuator piston by usinga spill valve that meters the potentiometric jet. The servo valve has ametered fuel pressure inlet from the actuator and a return outlet tothe fuel control unit The control current (0-100 MA) to the servo

Bleed Control Valve

The bleed control valve (BCV) delivers compressed air to the aircraft,also the valve functions as an anti-surge valve for the loadcompressor.





the fuel control unit. The control current (0-100 MA) to the servovalve is provided by the ECB.

Actuator


The position of the actuator piston is provided by a linear voltagedifferential transducer (LVDT). The position signal is sent to the ECB

for control of the servo valve.




COMPRESSED AIRREGULATED FUEL

METERED FUELFUEL RETURNFUEL DRAIN





The ECB provides a control signal (0-100 MA) to the servo valveusing the following inputs:

- APU bleed switch

APU Star ting

During start and shutdown the BCV is in the discharge position.

If the valve control is faulty, the BCV actuator will automaticallyposition the valve to discharge.





U b eed s tc

- Speed (100%)

- Air inlet temperature

- Load compressor discharge pressure sensor (ΔP/P).


When the actuator piston moves, the linear voltage differentialtransducer (LVDT) sends the actuator position signal back to theECB.


The actuator piston positions the BCV to deliver the maximum airflowto the aircraft pneumatic systems without causing load compressor

surge.

pos t o t e a e to d sc a ge







AIR SYSTEM SENSORS - INLET AIR PRESSURE AND TEMPERATURE SENSOR

Function

The air inlet pressure and temperature signals are used by the ECBfor control purposes.

Location

- Supply current: 1 mA

- Range: -55 to +150°C (-62 to 302°F)

- Resistance at 0°C (0°F): 1000 Ω.




The pressure and temperature sensors are in one unit which islocated on the right rear side of the air inlet plenum.

Main Features

Pressure Sensor

- Type: variable resistor device

- Excitation voltage: + 5 and - 5 VDC

- Output signal: 0 to 50 mV

- Range: 0 to 104 kPaa (0 to 15 PSIA)

- Minimum bridge impedance: 2000Ω.

Temperature Sensor

- Type: resistance temperature device


- The pressure sensor is made of a bridge of 4 resistors printed ona flexible support. One of them varies if the support is deformed bythe air pressure. The whole bridge is supplied by a 5 VDC constantsource voltage coming from the ECB. The changes of the variableresistor cause the output to vary (from 0 to 50 mV).

- The temperature sensor is a resistor which is fed by a constant 1mA current supplied by the ECB. The output voltage changes from

approximately 0.8 to 1.2 VDC according to the resistance changesfrom -55 to +50°C (-67 to +122°F).


- The measured ambient pressure is lower than 3.45 kPaa(0.5 PSIA) or higher than 110 kPaa (16 PSIA)

- The measured inlet temperature is lower than -62°C (-80°F) orhigher than 76°C (170°F)

Normal BCV control will be maintained if either air inlet pressure ortemperature sensor is failed.





AIR SYSTEM SENSORS


AIR SYSTEM SENSORS - LOAD COMPRESSOR DISCHARGE PRESSURE SENSORS

General

Function

The load compressor discharge pressure sensors sense loadcompressor air pressure (high pressure) and (low pressure).

Description

The two sensors are made of a bridge of 4 resistors.

The resistors are printed on a flexible support and one of them variesif the support is deformed by the pressure.





The ECB receives signals from the sensors and adjusts the bleedcontrol valve (BCV) to prevent load compressor surge.

Location

The pressure sensors (ΔP/P) are assembled as one unit. Thesensors are located on the right front side of the air inlet plenum.

Main Features

The pressure sensors are variable resistor devices.

Excitation voltage: + 5 and - 5 VDC

Output signal: 0 to 50 mV

Range 0 to 172 kPad (0 to 25 PSID) (ΔP)0 to 689 kPaa (0 to 100 PSIA) (P)

Minimum bridge impedance: 2000 Ω.

The bridges are supplied by a constant source voltage of 5 VDCcoming from the ECB.

The changes of the variable resistor causes the output voltage tovary (from 0 to 50 millivolt).


- The measured pressure is lower than 3.45 kPad (0.5 PSID) or

higher than 172 kPa (25 PSI) or than 690 kPa (100 PSI)

The load compressor bleed air pressure is displayed on the lowerECAM when the APU system page is selected.




LOAD COMPRESSOR DISCHARGE PRESSURE SENSORS

AIR SYSTEM SENSORS



Function

The accessory cooling system supplies air for the oil cooler and forthe APU compartment ventilation.

Location

Cooling Fan

The fan provides cooling air to the oil cooler and to the compartmentcooling duct. The fan assembly incorporates a permanent magnetgenerator that is used for APU backup overspeed and to preventmomentary power interruption of the ECB.





The system components are located on the APU.

Main Features

Cooling by circulation of air taken from the air inlet plenum andaccelerated by the cooling fan.

Main Components

The main components of the system are the fan inlet duct assembly,the cooling fan, the fan outlet duct assembly, the oil cooler and theoil cooler exhaust duct.

Fan Inlet Duct

This duct connects the engine air inlet plenum to the inlet of thecooling fan.

Fan Outlet Duct

This duct connects the outlet of the cooling fan to the inlet of the oilcooler.

Oil Cooler Exhaust Duct

This duct connects the oil cooler outlet to the APU compartment doorvent.

Compartment Cooling

The APU compartment is ventilated by air ducted from the coolingfan outlet duct. The air is discharged into the compartment throughthe compartment cooling duct.







General

Function

The cooling fan (driven by the gearbox) provides air circulation forthe oil cooler and ventilation of the APU compartment.

Main Components

- The cooling fan assembly includes:

• An axial flow fan

• The fan drive gear





The cooling fan incorporates a permanent magnet generator thatprovides momentary direct current power, and a backup overspeedsignal to the electronic control box.

Location

The cooling fan is located at the top of the gearbox front face and issecured by a V-band clamp.

Main Features

- Cooling fan rotation speed: 51965 RPM

- Permanent Magnet Generator output: 40 VDC (100% of N)

- Speed signal for back-up of the overspeed protection system:107%.

g

• 2 roller bearings


- A permanent magnet generator and control box.




COOLING FAN - GENERAL

ACCESSORY COOLING



Description

The cooling fan is mounted on the gearbox and aligned by a locatingpin. The fan mounting flange is secured to the gearbox by a v-bandclamp.

The fan is driven by a shaft assembly that is supported by two ball

Operation

Cooling Fan

The cooling fan accelerates the air flow through the oil cooler.Cooling air is also used for APU compartment cooling.





bearings, the bearings are lubricated by the APU oil system. Theshaft assembly uses a carbon seal and two labyrinth sealspressurized by the power section impeller air. The oil used forlubrication of the cooling fan is returned to the oil sump by gravity.

A permanent magnet generator (PMG) and a printed circuit boardare located in the fan housing. The printed circuit board contains therectifier components for the PMG electrical power output to the ECB.

The cooling fan can be used to turn the APU rotor assembly duringborescoping. This is accomplished by removing the fan inlet duct andmanually rotate the fan impeller.

PMG

The permanent magnet generator (PMG) is driven by the cooling fanshaft. The PMG provides momentary (240 msec) of rectifiedelectrical power to the ECB when the aircraft electrical power isinterrupted during power transfer.

One unrectified PMG output provides a frequency signal to the ECBthat is used for the back up overspeed signal.




AMBIENT AIROIL SUPPLYOIL DRAINPRESSURIZED AIR

COOLING FAN - DESCRIPTION AND OPERATION

ACCESSORY COOLING



The aircraft pneumatic system supplies compressed air to thefollowing:

- Aircraft air conditioning system

- Water tank pressurization





- Aft cargo heating

- Wing anti-icing system

- Main engine starting system

- Hydraulic reservoir pressurization.

The compressed air , used by the aircraft pneumatic system, can besupplied by:

- The APU

- Number 1 engine

- Number 2 engine

- Ground air source.

ENG. 1

HOT AIR

PACK 1ENG 2BLEED

PACK 2

X BLEED






APU COMPRESSED AIRENGINE FAN COOLING AIR

FAULT LIGHTOFF LIGHT

BLEED

GROUND AIR

SUPPLY

APUBLEEDVALVE(BCV)






APS 3200





SECTION 6

CONTROL SYSTEM



Functions

The functions of the APU Control System are:

- To keep the power unit rotation speed constant to maintain ACgenerator frequency

Main Components

The main components of the APU control system are:

- The APU components (sensors, pressure switches, servo-valve,actuators ...)





- To protect the power unit from overtemperature

- To avoid load compressor surge


- To provide a proper start sequence.

- To monitor APU component operation.

- To supply fault information for trouble shooting, engine trendmonitoring and historical data retention.

Main Features

- FADEC (Full Authority Digital Electronic Controller)

- Single computer

- Electrical supply from the aircraft DC system and momentarypower backup from the cooling fan PMG.

- The electronic control box

- The aircraft control panels.







General

This description considers:


- The ECB inputs

ECB Outputs

They are the accessories (electro-valves, relays...) and indicatingdevices.

ECB Electrical Supply

- 28 VDC supply: from the aircraft electrical system





- The ECB outputs

- The ECB supply


ECB

The ECB is located in the aft cargo compartment.

The unit is made of six printed wiring assemblies using digitaltechnology components.

ECB Inputs

They are the sensors (rotation speed, temperature, pressure...) anddiscrete signals (microswitches and switches).

- Momentary supply: from the permanent magnet generator (part ofthe cooling fan assembly).

Electrical Harness

The APU harness connects the APU to the aircraft electrical system.







Control System Components

Components of the control system:


- Oil filter switch indicators

High oil temperature sensor

- Inlet guide vane servo valve

- Bleed control valve servo valve

- Fuel servo valve


Low fuel pressure switch






- Oil level sensor

- De-oiling valve

- Speed sensors

- EGT sensors

- Inlet air pressure sensor

- Inlet air temperature sensor

- Load compressor discharge pressure sensor

- Linear voltage differential transducers (LVDTs)

- Low fuel pressure switch

- Permanent magnet generator

- Engine identification module

- Exciter

- Starter voltage sensing

- Centralized Fault Display System (CFDS)

- Aircraft discrete inputs and outputs.





CONTROL SYSTEM COMPONENTS



Rotation Speed Contro l

General

This function meters the fuel flow to maintain a constant rotor speed.

Components Involved

- Speed sensors

Exhaust Gas Temperature (EGT) Control

General

This function protects the power unit against over-temperature.

Components Involved

- EGT thermocouples the speed sensors and the inlet pressure and





Speed sensors


- Fuel servo-valve.


The ECB compares rotor speed with a nominal speed datum to

control the fuel servo-valve. The servo-valve then provides therequired fuel flow to maintain 100% rotor speed under all APU loadconditions.

EGT thermocouples, the speed sensors and the inlet pressure andtemperature signals

- ECB

- IGV actuator.


The ECB compares the actual EGT with an EGT datum.

The EGT datum is a function of the operating mode (ECS or MES)and of the ambient air conditions (P1 and T1).

The ECB controls the IGV servo-valve as a function of EGT.

The IGV's are modulated toward close as EGT exceeds the datum.




FUEL SUPPLYUN METERED FUELMETERED FUEL

APU CONTROL SYSTEM - OPERATION (1)FUEL RETURN

ROTATION SPEED CONTROL AND EGT CONTROL



Load Compressor Surge Control

General

This function protects the load compressor from surge.

Components Involved


Load Compressor Reverse Flow Protection

General

This function shuts down the APU in case of load compressor surge(eg. back pressure from the aircraft pneumatic system).

Components Involved





p p p


- Bleed control valve.


The ECB compares the load compressor delivery pressure ratio

(ΔP/P) with a datum pressure ratio. In case of a low airflow condition,the bleed control valve is modulated to discharge air into the APUexhaust.


- ECB

- Fuel system and bleed control valve.


The ECB compares the load compressor delivery pressure ratio withtwo datums:

When the first datum is reached, the bleed control valve (BCV) willmove to the discharge position.

When the second datum is reached, the APU will automaticallyshutdown.




METERED FUEL APU CONTROL SYSTEM - OPERATION (2)FUEL RETURN

LOAD COMPRESSOR SURGE CONTROL AND REVERSE FLOW PROTECTION



APU Star t Fuel Flow Control

General

This function meters the fuel flow during APU starting.

Components Involved

- Speed sensors, the EGT thermocouples, the air inlet pressure andt t b


The fuel flow program has two phases:

- The first phase: EGT rise

- The second phase: From EGT rise to 95% speed + 2 seconds.





temperature probes


- Fuel servo-valve.

During the first phase, the fuel supply is used to fill the manifold. Fuelflow is metered as a function of rotor speed only.

During the second phase, fuel flow is scheduled as a function of twoprograms (automatically selected):

The first program controls the fuel flow rate after comparing the

actual acceleration with the acceleration rate datum.

The second program controls the fuel flow rate after comparing theactual EGT with the EGT datum.




CONTROLSYSTEM

ECB


APU START FUEL FLOW CONTROL




APU Faul t Sys tem

General

The APU is either shut down automatically or a warning is given incase of a fault.

Components

The sensors





- The sensors

- The ECB

- The electrical accessories.

Operation

In the event of a fault shutdown of the APU, the supplied electricaland pneumatic loads are removed.

Warning lights, messages and indicators are displayed in the flightdeck.

Fault messages are available through the Centralized Fault DisplaySystem.




APU SAFETY SYSTEM




Monitoring

Function

The system provides information about the APU actual status,operation and maintenance.

The system displays:

- APU parameters





APU parameters

- Events and hours count

- Condition and faults.

Components Involved

- APU control system components

- The ECB

- The flight deck indicating system (CFDS, ECAM, MCDU).





MONITORING



Function

The Electronic Control Box (ECB) controls and monitors the AuxiliaryPower Unit systems.Location

The ECB is installed in the aft cargo compartment.

Main Features-Full Authority Digital Electronic Controller (FADEC)

Weight and Dimensions

Weight: 7.3 kg (16.1 lbs)Dimensions:Weight and Dimensions

-• Width: 159 mm (6.2 inches)• Height: 195.4 mm (7.6 inches)• Depth: 375.4 mm (14.6 inches).

Main Components






Full Authority Digital Electronic Controller (FADEC)- On Board Replaceable Memory Module (OBRM) for design

flexibility and reduced component count- Modular design for reliability, maintainability and testability- No calibration required- Digital communication links (ARINC 429 and RS 232-C)

The main components are:- The ECB enclosure which houses Printed Wiring Assemblies

(PWA)- The ECB front face which includes:

• A RS 232-C connector• A front cover door housing the On Board Replaceable

Memory Module (OBRM)

• A handle- The ECB rear face which includes an ARINC 600 connector.

Identification

The electronic control box has an identification plate and amodification plate, both located on the front face of the ECB.







ECB Inputs

General

This chapter considers the discrete and analog input signals to theECB.

The bleed control valve (BCV) command is transmitted to theECB by means of an aircraft discrete signal. Upon receipt of thiscommand, the ECB contro ls the opening o f the BCV to supplythe aircraft pneumatic sys tem.

Air/ground Conf iguration Switch (open/ground)





Sensors and Discrete Inputs from Ai rcraft to ECB

The corresponding signals form part of the ECB Inputs-Outputsdefinitions and PIN assignments.

APU Stop (ground)

The stop signal is transmitted to the ECB by the APU master switchin the flight deck. Actuating the switch causes a contact closure toground.

Bleed Control Valve Activation (ground)

Emergency Stop (ground for approx. 150 ms)

The emergency stop signal is transmitted to the ECB by means of a

discrete signal created by a contact closure to ground.

This signal to the ECB is to indicate whether or not the aircraft is in-flight operation. Special considerations (i.e. safety systems) apply forin-flight operation.

MES Mode (28 V)

This signal indicates to the ECB whether or not the aircraft is in MainEngine Start mode (MES) of operation. The circuit is normally open.In the MES mode, the aircraft causes the circuit to close and tosupply a 28 V signal to the ECB.

Start Contactor Monitor (28 VDC/open/ground)

This discrete 28 VDC signal tells the ECB whether or not the back-upstart contactor is closed or whether or not it is open.

The start contactor monitor is used exclusively for fault isolationpurposes.








Sensors and Discrete Inputs from Aircraft to ECB (continued)

Air Intake Flap Open Posi tion (28 VDC)

When the air intake flap is in the fully open position, a switch isactivated to supply a 28 VDC signal to the ECB.

This signal is used to initiate the start sequence.

JAR Configuration

Low Fuel Pressure Switch (open/ground)

The switch closes to ground when the fuel pressure falls below agiven pressure.

Air Intake Flap Closed Posit ion (ground)

When the air intake flap is in the fully closed position, a switch is

activated to the closed position and provides a ground signal to theECB. The aircraft relay operation is maintained until the flap closedsignal is received





The ECB is programmed in the JAR mode. This means that allshutdown faults sensed by the ECB will cause the APU to shutdownon the ground or in flight.

Start Command (28 VDC for approx. 150 ms)

This command is activated by momentarily placing the start button inthe flight deck to "on". This action provides a 28 V signal to the ECB.

signal is received.

Air Intake Flap Movement (28 VDC)

During normal APU operation, a 28 VDC signal is transmitted to theECB when voltage is being applied to open or close the air intakeflap.

Generator Oil Temperature Sensor (100 )

This sensor is mounted in the AC generator. The wiring uses thegenerator connector, P4. The sensor is a resistance temperaturedevice (RTD). It's variable resistance is a function of temperatureand is supplied with a constant current of 1 mA.








Sensors and Discrete Inputs from APU to ECB

Low Oil Pressure Switch (ground)

The low oil pressure switch is a normally closed contact. The switchopens and remains open when oil pressure is present.

Oil Filter Switch Indicators

This is a differential pressure switch that is normally open. Thecontact closes and provides a ground signal in case of filter

This sensor is a variable resistance device supplied by a constantsource voltage of 5 VDC.

The output ranges from 0 to 50 mV for a 0 to 15 PSIA range of airpressure.

Load Compressor Discharge Air Pressure Sensors (P) and (

P)

There are two sensors: one to measure the pressure at the loadcompressor scroll (P), the other one to measure the differential airpressure between the diffuser and the scroll (AP). The ratio signal





p g grestriction.

EGT Sensors

The EGT is measured by two independent thermocouples. They areK type (Chromel-Alumel).

The output is of approx. 1 mV per 24°C (43°F).

High Oil Temperature Sensor (100 )

The sensor is a Resistance Temperature Device (RTD). Theresistance varies according to the oil temperature and is suppliedwith a constant current of 1 mA.

Inlet Air Pressure Sensor

p ( ) g AP/P is used to prevent load compressor surge.

The two sensors are of variable resistance type supplied by aconstant voltage of 5 VDC.

The outputs range from 0 to 50 mV for a 0 to 100 PSIA (absolute) or

0 to 25 PSID (differential) ranges of air pressure.

Rotation Speed Sensors

There are two independent speed sensors mounted in the gearbox.

They provide a wave signal as a function of the teeth on the phoneticwheel (24) and the rotation speed (i.e. 19720 Hz at 100% speed).




SENSORS AND DISCRETE INPUTS - FROM APU TO ECB





Inlet Air Temperature Sensor (1000 RTD)

The sensor is a variable resistance temperature device supplied by aconstant source current of 1 mA. Temperature range -55 to 150°C(-67 to 302°F).

Engine ID Module

The engine identification (ID) module is resistors that provide the

IGV and Bleed Control Valve LVDTs(Linear Voltage Differential Transducer)

LVDTs are used to detect the actual displacement of the IGV andBCV actuators. Their signal is fed back to the ECB for the purpose ofservo control.

Their primary coil is supplied with a constant voltage of 10 VAC.

Their secondary coil provides a variable output voltage.

Upon loss of electrical signal, the IGV will close or the BCV opens to





ECB with 3 voltage lines V 1, V2, V3 matched to the engine IDnumber. The engine serial number is the sum of the ID number andthe number 1000.

The engine ID number is stored in the ECB NOVRAM memory aspart of the power up initialization. The ID module is considered failed

when all inputs are shorted, one or all inputs are open, a numbergreater than 2048 is used, or 3 consecutive readings at power upinitialization are not identical.

discharge.

Oil Level Sensor (100 A)

The gearbox mounted oil level sensor is a Resistance TemperatureDevice (RTD) type. The variable resistance value is provided with a

constant current of 75 mA. The oil level is checked at power up overa period of 8 seconds and is determined OK or LOW.









Permanent Magnet Generator (PMG)

A Permanent Magnet Generator (PMG) is installed in the cooling fan.The assembly consists of the PMG rectifier circuit and a DC fusiblelink.

The PMG provides the ECB with rectified power and one unrectifiedsignal from one of the three phases (backup overspeed protection at107%).

Starter Motor Voltage

The starter motor is monitored by the ECB for low voltage during APU start. The low voltage sensing connector is located on the frontface of the starter motor housing.





The unrectified output is current limited (short circuit protection) bymeans of a resistor. The fusible link trip point is at 10 A.

The rectified output provides 40 VDC at 100% speed for back-uppower supply to the ECB in the event of a momentary interruption in

the main power supply. This back-up supply lasts for 240 msec.

Note: The failure of the PMG/Speed circuit at startup will cause the APU to shutdown during acceleration.








ECB Outputs

General

This chapter considers the discrete and digital outputs of the ECB.

Discrete and Digital Outputs (to the aircraft)

Backup Start Contactor (28 VDC, 1 A nominal)

This contactor is energized by means of a discrete signal. The signalis supplied through a Field Effect Transistor (FET) in the ECB

Bleed Control Valve Open (28 VDC, 0.1 A)

The ECB transmits a discrete signal to the aircraft indicating systemwhen the bleed control valve is in the position that allows maximumflow to the aircraft pneumatic system.

APU Available (28 VDC, 0.4 A)

The ECB provides a discrete signal to the AVAIL light in the startswitch when the APU has completed the start sequence and is readyto load.





is supplied through a Field Effect Transistor (FET) in the ECB.

Main Start Contactor (28 VDC, 1 A nominal)

This contactor is energized by means of a discrete signal. The signalis supplied through a FET device in the ECB.

Aircraf t Relay (ground, 0.4 A)

The aircraft relay is activated by a closed contact to ground throughthe ECB. The aircraft relay is activated when the ECB is energizedand no stop command is present.

Start in Progress (28 VDC, 0.1 A)

The ECB transmits a discrete signal to the ON light in the start switchto indicate a start is in progress.

The light is "ON" from the beginning of the start until the "APUavailable" light turns on.

Fault (28 VDC, 0.2 A)

The ECB transmits a fault discrete signal to the aircraft for allshutdowns.








Discrete and Digital Outputs (to the aircraft) (continued)

Flap Open Command (28 VDC, 3.5 A)

The ECB provides a power output for opening the air intake flap. Theflap open command is emitted through a FET device in the ECB.


Flap Closed Command (28 VDC, 3.5 A)

The ECB provides a power output for closing the air intake flap. The

• ARINC 429 input from ECS: It is used by the ECB toreceive specific data from the Environmental ControlSystem (i.e. ECS demand signal, ECS valve status word,etc...)The ECS demand signal is used in the control of the IGV's.The ECS valve status word informs the ECB of the numberof air conditioning packs currently supplying air

• ARINC 429 CFDS output: The ARINC 429 outputtransmits data to the CFDS, ECAM (Electronic Centralized

Aircraft Monitoring) and ACMS (Aircraft ConditionMonitoring System)





p p p g pflap closed command is emitted through a FET device in the ECB.


Aircraf t Serial Communications

Data communication is achieved by means of four serialcommunication links:

- ARINC 429 CFDS output: Three ARINC 429 serial links (theyoperate at low speed - 12.5 K bits/sec)

• ARINC 429 input f rom CFDS: It is used by the ECB toreceive specific data from the Central Fault DisplaySystem with appropriate ARINC labels

- One RS 232 C interface: This interface is accessible on the rear ARINC connector and on the front face connector.

It can be used:

• As a maintenance tool

• To access the test modes of the ECB

• To change the ECB software characteristics duringdevelopment.








Discrete and Analog Outputs (to the APU)

Oil System De-oili ng valve (28 VDC, 1 A)

This output is activated to operate the valve during starting andshutdown.

Exci ter (28 VDC, 2 A)

This output is activated to supply the exciter during starting.

3 Way Solenoid Valve (28 VDC, 1 A)

IGV and Bleed Control Valve LVDTs (3000 Hz, 10 VAC)

These two separate outputs supply a reference source signal to eachprimary coil.

IGV, Bleed Control Valve, Fuel Servo (0 - 100 mA)

These three separate outputs supply a variable low intensity signal to

the corresponding servo-valve.





This output is activated to operate the valve for start and shutdown.

Oil Level RTD, Oil Filter and LOP switches (Rtn, 1 A)

This output is common to all three items.

Pressure Transducers Excitation (5 VDC, 30 mA)

This output is activated to operate the air pressure transducers witha stabilized voltage.




DISCRETE AND DIGITAL OUTPUTS (TO THE APU)




Hardware Description

The Electronic Control Box consists of an enclosure which includesthe following components:

- Six Printed Wiring Assemblies (PWA):

• A speed and temperature PWA

• A discrete input-output PWA

• A microprocessor PWA

- An On Board Replaceable Memory Module (OBRM) accessiblethrough a removable front cover door.

The board is equipped with an UVPROM type memory to be usedas the programme memory space for the ECB.

- Two electrical connectors:

• A RS 232 connector located on the ECB front face

• An ARINC 600 connector located on the ECB rear face.





• An analog input PWA

• An analog output PWA

• A power supply PWA

- One printed wiring assembly for Electromagnetic Interference(EMI) and lightn ing protection

- PWA guides

- A backplate to interconnect the various PWA

- One High Power Switch FET Module (FET: Field EffectTransistor)

- One Input Power Filter Module




HARDWARE DESCRIPTION




General

The operating phases are:

- Power up

- Watch state

- Start preparation state

- Starting state

- Run state

Power Up State

GeneralWhen the APU master switch is selected to ON, the ECB enters thePOWER UP state.The POWER UP state lasts approximately 3 sec.OperationThe ECB checks that outputs are not energized except those that

are required.The ECB enters self test.The ECB is able to recognize and record the occurrence of start oremergency stop signals.Upon receipt and validation of the start signal, the "start in progress"





Run state

- Cool down state

- Shutdown state

p p g , p goutput is energized.The requirement to activate the "start in progress" output alsoapplies to the WATCH state.In case of an emergency stop signal being received, the ECB closesthe air intake and deactivates the aircraft relay output once the air

intake is closed.







Watch State

General

After completion of the POWER UP state the ECB automaticallyenters the WATCH state.

Operation

The ECB is able to recognize and record the occurrence of start oremergency signals.

Upon receipt of an emergency stop signal the ECB closes the air

Start Preparation State

General

Upon receipt of the start command, the ECB enters the STARTPREPARATION state.

Operation

During this state the flap actuator position, the oil level and therotation speed is checked. If the speed is greater than 7%, the startcommand will be inhibited until the speed is less than or equal to 7%.





p p g y p gintake and deactivates the aircraft relay output once the air intake isclosed.

The ECB self tests as required.

The ECB enters the START PREPARATION state automaticallywithout requiring a new start command.







Starting State - Sequences

General

The STARTING STATE is controlled by the ECB.

A stop signal at any time during the STARTING STATE willshutdown the APU.

Operation

The electrical sequences selected by the ECB are:

B k l

- EGT rise

• Acceleration control to steady state speed control.

- At 55% speed

• Exciter de-energized

• Gearbox de-oiling valve and main start contactor de-

energized.

- At 55% speed + 5 sec

• Backup start contactor de-energized





- Backup start contractor supply

- Gearbox de-oiling valve

- Exciter

- Main start contactor


- Pulse fuel servo valve

- Manifold fill algorithm

- Open loop fuel schedule activation.

Backup start contactor de energized.

- At 95% speed + 2 sec.


• APU available signal activated

• Start in progress output de-activated

• Steady state speed control loop activated

• Enter RUN STATE.







Starting State- Fuel Control

General

There are three consecutive programs used to supply and meter thefuel during starting:

- Manifold Fill Algorithm

- Open Loop fuel schedule

- Acceleration control

Manifold Fill Algorithm General

Accelerat ion Control - General

This control occurs from EGT rise until steady state speed control isreached.

Fuel flow during acceleration is controlled by speed and EGT signalsto the ECB.





Manifold Fill Algorithm - General

During engine start up the ECB controls the fuel servo valve toimplement the manifold fill algorithm.

The control is an open loop schedule based on the rotation speed,this ends when a given quantity of fuel is delivered to the manifold.

Open Loop Fuel Schedule - General

This fuel schedule replaces the manifold fill algorithm when the flowdelivered has reached 0.01 kg/m (0.032 lb/m).

The schedule determines a fuel flow rate depending on rotation

speed, ambient pressure and temperature. It is considered the"basic" fuel flow needed to obtain combustion in the combustorchamber.




STARTING STATE - FUEL CONTROL




Run State- Fuel and Load Compressor Control

General

Upon completion of starting, three main functions are activated:

- Speed control

- Load compressor surge control

- EGT control.

Speed Control - General

Load Compressor Surge Control- General

This function prevents load compressor surge. This is accomplishedwhen the bleed switch is ON.

EGT Control - General

To prevent EGT over temperature during load compressor operation,

the ECB will automatically move the IGV's to decrease airflow andreduce the work load on the power section.

The AC generator output has priority overload compressor operation.





The purpose of speed control is to maintain the APU at 100% speedunder all load conditions. This is accomplished by the fuel controlunit increasing or decreasing fuel flow automatically when APU loadchanges occur.




GEARBOXGEARS

AMBIENT AIRCOMPRESSED AIRMETERED FUELCOMBUSTIONEXHAUST

RUN STATE - FUEL AND LOAD COMPRESSOR CONTROL - GENERAL




Cool Down State

General

This function allows the APU to operate in a no-load condition beforeentering the shutdown state.

When the APU master switch is selected to OFF, all loads areremoved (IGV's closed, Bleed Control valve to discharge).

If the APU was providing bleed air at this time, the APU will continueto run in a cool down mode for a maximum time of 2 minutes.

The cool down mode time limit can vary from 0 to 2 minutes. The





time limit depends on when the APU bleed switch is turned off priorto selecting the APU master switch to OFF.


SHUTDOWN STATE.




COOL DOWN STATE




Shutdown State

General

The APU enters the shutdown state after a normal shutdown or afault shutdown occurs.

Note: The APU can be re-started during the shutdown state. Thisis accomplished by cycling the master switch OFF to ON andthen selecting the APU start switch to ON.

The ECB does not close the flap and the APU automaticallyre-starts when 7% speed is reached.








SHUT DOWN STATE

ELECTRONIC CONTROL BOX – OPERATION (7)



Condition Monitor ing Data

General

For long term trend monitoring, the APU control system records theengine operating parameters.

Operation

APU conditioning monitoring parameters are taken during operationof the APU. The ECU does not store this information but it may beretrieved from the Aircraft Integrated Data System (AIDS) if thissystem is installed.

The following parameters are:

In addition, the ECB records:

- APU operating hours (in one minute increments from speed > 55%until the 3-way solenoid valve is de-energized.

- Number of starts (1 start = EGT rise detected + speed > 30%)

- ECB operating hours (in one minute increments, from ECB powerON to ECB power OFF).

The condition monitoring data is associated with the engine





g p

- Exhaust Gas Temperature °C

- Engine speed %

- Engine inlet pressure PSIA

- Engine inlet temperature °C

- Fuel flow LB/HR

g gidentification (ID) number, ECB serial number.

Note 1: The condition monitoring parameters are not taken when

either the inlet pressure or temperature sensors are faulty.

Note 2: If the engine ID module has been determined failed, the APU system operating history data will be associated withthe last valid engine I D number.When a new engine ID number occurs, it is used withouterasing the previously recorded historical data.The oldest data is overwritten by the new data as it isrecorded.

The ECB records the condition monitoring data associatedwith the last APU cycle and the data is available via the ARINC 429 link.




BUILT-IN TEST - OPERATION - POWER UP TEST





HPS CT/NOV. 2006 Page 6. 53 HAMILTON SUNDSTRAND PROPRIETARY




SECTION 7




INDICATING SYSTEM


INDICATING SYSTEM

Main Components

- APU components (speed sensors, thermocouples and engine IDmodule)


- The aircraft control panel which includes:

• APU master switch and APU start switch

• ECAM, MCDU

• FUEL, AIR CONDITIONING, ELECTRIC and FIRE controlpanels

Note: This chapter covers the APU indicating components andprovides general information on the aircraft system.

ECAM: Electronic Centralized Aircraft Monitoring.

MCDU: Multi-function Control and Display Unit.





• MASTER WARNING and MASTER CAUTION LIGHTS

- The EXTERNAL CONTROL PANEL.




INDICATING SYSTEM



Function

The rotation speed signal is used by the ECB for:

- Indication

- Fuel metering

- ECB Sequencing

- ECB Control functions.

Main Features

Two sensors.

Main Components

- One "phonic" wheel with 24 teeth

- Two electromagnetic sensors (single coil)

- Harness

- ECB.


The phonic wheel is secured to the rotor front bearing journal.

The two speed sensors are located in the gearbox housing at 5' l k d 7 ' l k E h i d b i l b lt





Interfaces

The ECB provides the speed information to the CFDS/ECAM displaysystem.

o'clock and 7 o'clock. Each one is secured by a single bolt.




UN METERED FUEL

METERED FUELOIL LEVEL



ROTATION SPEED INDICATION SYSTEM -DESCRIPTION AND OPERATION

Description

- Phonic wheel has 24 teeth

- Two single coil speed sensors (the coil surrounds a magnetic core)

• Phonic wheel-speed sensor gap: 0.5 mm (0.018 inch); gapnot adjustable

- The two sensors are connected to the ECB

• Frequency signal at 100 %: 19720 Hz (49300 RPM)

• Frequency signal range: 0 to 24 KHz; 0 to 50 volts.

Operation

The phonic wheel rotates with the rotor assembly, as the teeth passby each speed sensor they generate a voltage. The voltage isproportional to the speed of the phonic wheel. The signal is sent tothe ECB for speed indication and system control.

The ECB will calculate the average signal of the two speed sensors.In the event a signal difference of 5% or more occurs, the ECB willselect the sensor indicating the highest value.

APU speed indication is displayed on the lower ECAM when the APU system page is selected.








ROTATION SPEED INDICATION SYSTEM - DESCRIPTION - OPERATION



Function

The EGT signal is used for:

- Indication

- Load compressor control

- Sequences

- Control functions.

Main Features

The system uses K type chromel-alumel thermocouples and has acold junction compensation built into the ECB.

Main Components

- Two thermocouples

- Harness

- ECB.


The two thermocouples are located in the power section exhausthousing.





j p

Interfaces

The ECB provides the EGT information to the ECAM display system.






EGT INDICATION SYSTEM - DESCRIPTION AND OPERATION

Functional Descripti on

Each thermocouple is secured into the exhaust housing by a bolt.

They are connected separately to the ECB.

Operation

The thermocouple generates a millivolt signal to the ECB that is usedfor engine control and indication (EGT)

The voltage value is of approximately 1 millivolt per 24°C (43°F).

The ECB compensates automatically the cold junction effect andcalculates the average EGT value.





g

An EGT system failure is declared if:

- EGT is lower than 120°C (250°F)

- EGT is higher than 1200°C (2200°F).

The ECU will calculate the average signal of the two thermocouples.In the event a signal difference of 121°C (250°F) or more occurs, theECB will select the thermocouple indicating the highest value.

APU exhaust gas temperature indication is displayed on the lowerECAM when the APU system page is selected.




EGT INDICATION SYSTEM - DESCRIPTION - OPERATION



Function

To provide the engine serial number to the ECB.

Location

The module is installed on the ignition exciter support bracket (APUleft side).

Main Features

The ID module consists of a printed circuit board.


The ID module uses resistors located on a printed circuit board.

The board is housed in an electrical plug and is connected to theECB by means of 4 electrical wires.

There are 3 voltage lines V1, V2, V3 and a return line.

The engine ID number is read, validated and stored during the powerup phase of the ECB.

In case of ID module failure, the APU history data will be associatedwith the last valid ID number.

When a new engine ID number occurs, it is used without erasing thepreviously recorded historical data





previously recorded historical data.







General

This system gives information about the APU actual status, foroperation and maintenance.

Description

Indication of operating parameters

The APU operating parameters are displayed on the lower ElectronicCentralized Aircraft Monitoring (ECAM) when the APU system pageis selected.

Maintenance and fault isolation

The ECB provides maintenance and fault information to the aircraftCentralized Fault Display System (CFDS) This information is

Warning, caution and indicating lights

MASTER WARNING, MASTER CAUTION and annunciator lightsprovide visual warning indications.

A FAULT light is incorporated in the APU master switch button, APUGEN button and APU BLEED button.

There are also the following lights:

- APU "ON" light in the APU master switch

- APU "START / ON" and APU "AVAILABLE" light in the APU startbutton

- APU GEN "OFF" light in the APU GEN button





Centralized Fault Display System (CFDS). This information isdisplayed on the Multi-function Control and Display Unit (MCDU) in

the flight deck.

Warning messages

APU warning messages are displayed on the upper ECAM and the APU system page appears on the lower ECAM.

- APU BLEED "ON" light in the APU BLEED button

- APU fire lights on the external control panel and in the flight deck.












SECTION 8

STARTING SYSTEM




STARTING SYSTEM



Function

The starting system allows the APU to be started on the ground andin flight.

Starting requires:

- The cranking of the rotor assembly

- The fuel supply

- The ignition of the air-fuel mixture

- The automatic control of starting sequences.

Starting Requirements

Starting System Components

- Starter motor for cranking

- Ignition exciter and igniters for ignition

- Fuel system

- Control components (Electronic Control Box, APU Master Switch,

External Control Panel, Fire Extinguishing Panel).





- Starting envelope. Normal start throughout the operating envelope:

minus 300 m to 11900 m (minus 1000 ft to 39000 ft)

- Starting time from zero speed to governed speed: less than 80seconds

- Starting attempts: 3 consecutive starts and cooling for 1 hour.






STARTING SYSTEM - DESCRIPTION

The components involved are the starter-motor, the ignition exciter,the igniters and components of the fuel system and control system.

Starter-Motor

The electric starter motor drives the APU rotor assembly through asprag clutch.

The starter motor is mounted on the gearbox and aligned by a

locating pin. A V-band clamp is used to secure the starter to the drivepad.

A brush wear indicator pin and a starter low voltage sensingconnector are located on the front of the starter.

When brush wear reaches 75%, an indicator pin will appear in theplastic viewing window. (See Page 8.8)

Ignitor Cables

There are two igniter ignitor cables (one for each ignitor plug) thatdelivers high voltage from the exciter to the ignitors.

Ignitor Plugs

Two ignitor plugs are used to ignite the fuel in the combustorchamber. The ignitors are threaded into the combustor housing.

Control System

- Start switch and master switches

- Electronic Control Box.





Starter low voltage is sensed by the ECB through the low voltagesensing connector.

Ignition Exciter

The ignition exciter is located on the left side of the APU. The exciteris a capacitor-discharge unit that uses 28V DC to provide anintermittent high voltage output to the two ignitor plugs.




ECB

STARTING SYSTEM- DESCRIPTION



Start Selection

Starting is selected from the aircraft control panel:

- Master switch "on"

- APU system page on lower ECAM annunciates ...

- Start button.

Starting Operation

- Cranking

Energize the starter motor.

- Fuel supply

APU starting is controlled by the electronic control box.

The main phases are:

- Initial phase (cranking, fuel supply and ignition)

- Self-sustaining speed (de-energize the starter motor and ignitionexciter)

- 100% speed (speed governing and loading).

Shutdown Sequence

APU shut-down can be activated automatically or manually:

- Manually from the APU master switch, from the fire control panelor from the external control panel





Fuel servo valve and 3 way solenoid valve energized open.

- Ignition

Ignition exciter energized to provide ignition to the two ignitorplugs.

Starting Cycle

- Automatically by the ECB fault shut-down system.

The ECB controls the fuel control unit 3 way solenoid valve. Whenthe APU is shut down manually or automatically the 3 way solenoidvalve is de-energized closed. The closed valve shuts off the fuel tothe fuel injectors.







Function

The electric starter motor cranks the APU during the starting state.

Location

The starter-motor is mounted by a V-band clamp on the gearboxstarter drive pad.

Main Features

- Motor type:

- Weight: 4.22 kg (9.3 lbs)

- Voltage: 24 VDC (max. 28 VDC)

- Max current: 830 A.

Main Components

- The starter motor assembly

- The V-band clamp for attachment

- Positive and negative terminals

- Visual brushwear indicator

- Starter low voltage connector.

Interfaces

- Electrical power to the starter motor is provided by the aircraftbattery system through two start contactors (backup and main)

- Starter low voltage sensing





g g

- Starter motor clutch.

(See Page 8.3)

(See Page 8.3)






STARTER MOTOR CLUTCH

General

Function

The function of the clutch is to disengage the starter motor when the APU reaches self-sustaining speed.

Description

The clutch is a Line Replaceable Unit. It is necessary to remove thestarter motor and the bearing support assembly to extract the clutch.

The clutch assembly consists of two gears, a starter motor driveshaft, 4 bearings and a sprag clutch.

Operation

Two operating phases are considered : starter motor engaged andstarter motor disengaged.

Starter Motor Engaged

When the starter motor is operating, the sprag pawls make contactwith the starter motor shaft and the gear assembly.

Starter Motor Disengaged

At 55% speed the starter motor is de-energized by the ECB.

As the starter gear speed increases, centrifugal force moves thesprag pawls away from the starter motor shaft.

The starter motor shaft is disconnected from the sprag pawls, this





prevents the APU from driving the starter motor mechanically.




OIL SUPPLYSTARTER MOTOR CLUTCH - OPERATION


IGNITION EXCITER - GENERAL

Function

The ignition exciter transforms low DC voltage into intermittent highvoltage supply to the ignitor plugs.

Location

The ignition exciter is mounted on the left side of the APU.

Main Features

- Voltage range: 10 VDC to 30 VDC

- Energy: 0.22 Joules per spark

- Spark duration: 15 microseconds

- Spark rate: 2 Hz at voltage above 10 VDC.

IGNITION EXCITER - DESCRIPTION

The ignition exciter is a sealed metal box assembly with a mountingbracket.


- An input circuit with a connector and a DC/AC converter

- A high voltage transformer

- A high voltage output circuit with a rectifier, two capacitors and atriggering device.

The ignition exciter DC input voltage is sensed by the ECB for faultdetection.








IGNITION EXCITER - GENERAL - DESCRIPTION


IGNITORS AND IGNITOR CABLES

Function

There are two ignitor plugs used to ignite the fuel in the combustorchamber during start up of the APU. They are connected to theignition exciter by two shielded ignitor cables.

Location

The two ignitor plugs are located on the combustor housing:

- One at 5 'o'clock

- One at 9 'o'clock.

Note: Location is looking at the combustor housing rear view.





IGNITORCABLES




IGNITORS




HSPS CT/NOV.2006 Page 8.15HAMILTON SUNDSTRAND PROPRIETARY




SECTION 9

ELECTRICAL SYSTEM





ELECTRICAL SYSTEM

Functions

To operate the electrical accessories by control signals from theECB.

To supply AC power from the APU generator to the aircraft electricalsystem.

Main Features

- DC power

- AC power.

Main Components

- The electrical accessories

- The ECB









ELECTRICAL SYSTEM



Description

ECB connectors

The ECB has 2 connectors:

- An ARINC 600-2 connector with 3 inserts (A, B, C)

- A RS 232 C connector.

The ARINC 600 connector is installed at the rear of the ECB andplugs into a shelf mounted aircraft connector.

The ARINC 600 connector carries all inputs/outputs of the ECB plusthe ARINC 429 data link.

The RS 232 connector can be accessed through the front and therear connectors for maintenance purposes.

Aircraf t harness

- DC power to ECB and start contactors

- ARINC 429 data link

- AC generator control

- AC generator excitation control

- RS 232 C connector.

There are three firewall connectors that connect the ECB to theengine harness. They are identified as (J-1, J-2 and J-3).








ECB CONNECTORS - AIRCRAFT HARNESS





APU eng ine harnessThe engine harness is connected to three firewall connectors, theyare identified as (P-1, P-2 and P-3).P1 connector:- PMG- 3 way solenoid valve- Ignition exciter- Starter Motor (low voltage sense signal)- Bleed Control Valve LVDT- Gearbox de-oiling valve- Oil filter switch indicators- Low oil pressure switch- Oil level sensor- Low fuel pressure switch- Generator high oil temperature sensor- AC generator current transformers.

P2 connector:- Load compressor discharge pressure sensors- IGV actuator (servo valve and LVDT)- BCV actuator (servo valve)- Fuel servo valve- Speeds sensor 1 and 2- Oil temperature sensor- EGT sensor 1 and 2- Engine ID module- Air inlet pressure and temperature sensor.P3 connector:- AC generator PMG- AC generator excitation control.








APU HARNESS





Starter motor electrical power supply cables

The starter motor DC power supply is provided by the aircraftbatteries or the Transformer Rectifier Unit (TRU).

The supply is controlled by two contactors in series (backup andmain start contactors). The power cables link the start contactorsdirectly to the starter motor (+ and -cables).

AC generator harness

The AC generator connector P-4 is part of the engine harness. Theconnector provides the following signals:

- AC generator oil temperature and control signals through the P-1engine harness connector

- AC generator PMG signal and exciter field control through the P-3engine harness connector.

The four AC generator cables are connected to the aircraft electricalbuss system. Three of the cables provide AC power and the fourthcable is a neutral.








STARTER MOTOR CABLES - AC GENERATOR HARNESS




FunctionThe AC generator (Alternating Current Generator) provides electricalpower to the aircraft systems.LocationThe AC generator is mounted on the front face of the gearbox.Type- Brushless- 3 phases- Oil cooled.Main Features

- Nominal power: 90 kVA- Output: 115 V, 400 Hz- Rotation speed: 24 034 RPM at 100 % APU speed- Direction of rotation: Clockwise viewing the pad- Weight: approx. 22.7 kg (50 lbs).

Interfaces- Oil system (lubrication, cooling)- Generator Control Unit (GCU)- Electronic Control Box (ECB).Main Components- Permanent Magnet Generator- Current transformers- High oil temperature sensor (HOT).











The APU AC generator is connected to the aircraft electrical systemsthrough the APU line contactor.

The lower ECAM, APU system page displays the AC generatorparameters:

- The percent of load

- The output voltage (115 V)

- The output frequency (400 Hz).
















SECTION 10

APU INSTALLATION





APU COMPARTMENT

The APU compartment is located inside the aircraft tail cone.

The compartment is fire proof using firewalls made of titanium alloy.

Two longitudinally-hinged access doors provide access to the APUcompartment.

The air inlet duct assembly is attached to the right access door andprovides a ducted airflow to the APU air inlet plenum.

The APU compartment has a fire extinguishing bottle located in aseparate compartment, forward of the firewall.

Cooling and ventilation of the compartment is provided by the APUcooling fan. The fan provides air flow to the oil cooler and the APUcompartment.





APU COMPARTMENT AMBIENT AIRCOMPRESSED AIR





APU COMPARTMENTCOMPRESSED AIREXHAUST GAS

APU ATTACHMENT

The APU is attached to the aircraft tail cone structure by three struts.The struts are connected to the APU through vibration isolators.

The two forward struts are attached to mounts on each side of thegearbox. The rear strut is attached to the power section impellercontainment shield.

A lifting eye is also provided for installation and removal of the APU.









APU ATTACHMENT

AIR INLET SYSTEM

Function

The air inlet system provides ambient air to the APU air inlet plenum.

Location

The air inlet is located on the underside of the tail section.

System Components

The air inlet system includes:

- The diverter

- The air inlet

- The diffuser

- The elbow

- The interface with the APU inlet plenum.

The Diverter directs ambient air flow into the air inlet when theaircraft is operating at high airspeeds.

The Air Inlet has a flap that is opened and closed by an electricactuator. The actuator is controlled by the ECB.

The Diffuser slows the airflow delivery to the APU.

The Elbow is attached to the diffuser and directs the ambient airflowinto the APU air inlet plenum.

The air inlet duct assembly is secured to the right access door andcan be removed to provide better accessibility to the APU.





AMBIENT AIR




AIR INLET SYSTEM


EXHAUST SYSTEM

Function

The exhaust system directs the APU exhaust gasses overboard.

Location

The system is installed in the tail cone between the APU exhaustand the end of the tail cone.

System Components

- The exhaust pipe

- The exhaust muffler

- The insulation

- The sealing ring.

The exhaust pipe is mounted on rails that are attached to the insideof the tail cone.





This allows the exhaust pipe to be disconnected from the APU andmoved rearward to provide additional clearance during removal andinstallation of the APU.





EXHAUST SYSTEM

EXHAUST GAS

DRAIN SYSTEM (1)

Function

The APU drain system provides drains from various components.The fluids are collected and drained overboard through the drainmast.

The fuel control unit, BCV actuator and IGV actuator use a commondrain to the aircraft drain tank. Fluids are siphoned from the draintank, into the drain mast and then discharged overboard when theaircraft is in flight.

The other common and single drains flow directly into the drain mastand then discharge overboard.

APU Drains and Vent

- Combustor Drain

- Air Bypass Plenum Drain

- Exhaust Pipe Drain

F t B i S l D i

- Flow Divider Purge Drain (To exhaust)

- Gearbox Vent (To exhaust).





- Front Bearing Seal Drain

- Fuel Control Unit Drain

- BCV Actuator Seal Drain

- IGV Actuator Seal Drain

SIPHON TUBE

COLLECTORTANK





DRAIN SYSTEM (1)

DRAIN FLUID

FIRE PROTECTION

APU fire protection consists of a detection system and an

extinguishing system. The systems are supplied by the aircraftmanufacturer.

Fire Detection and Extinguish ing

The detection system uses two continuous sensing elementsinstalled on the APU compartment walls.

One fire bottle is available for fire extinguishing. The bottle is

installed on the forward side of the APU compartment firewall.

Operation

The APU fire control panel is located in the flight deck overheadpanel.

Pushing the fire switch will immediately shut down the APU and armthe fire extinguishing system.

In the event of an APU fire on the ground, the APU will automaticallyshutdown and discharge the extinguishing system.








FIRE PROTECTION








SECTION 11

MAINTENANCE






Visual Inspections

Opening the APU compartment for corrective maintenance orservicing provides the opportunity to visually inspect the APU forsecurity, leaks, and warning indicators. The following arerecommended inspection items:

- Engine mounts

- Engine Components and Fluid lines

- Oil Quantity and Magnetic Drain plug

- Oil and Fuel Filter impending blockage Indicators

- Electrical harness and Connectors

- Engine Air Inlet Plenum

- Engine Combustor Housing and Exhaust System.

Borescope Inspection

The APU internal components may be inspected by using a flexibleborescope. To rotate the APU internal components, the cooling faninlet duct may be removed to allow manual rotation of the fanimpeller.

The following components can be inspected with the APU installed inthe aircraft.

- Load compressor impeller and guide vanes

- Power section impeller

- Combustor, viewed through the ignitor and fuel injector bosses

- First stage turbine wheel

- Second stage turbine wheel.

Refer to the Aircraft Maintenance Manual for borescopeprocedures.








VISUAL INSPECTIONS - BORESCOPE INSPECTION



LINE REPLACEABLE UNITS

The following Line Replaceable Units (LRU's) can be removed andreplaced without removing the APU from the aircraft:

Electronic Control BoxEngine HarnessIdentification ModuleStarter MotorClutch AssemblyIgnition ExciterIgnitor CablesIgnitor PlugsSpeed SensorsThermocouples

Air Inlet Pressure And Temperature SensorOil Filter ElementsSwitch IndicatorsMagnetic Drain PlugDe-Oiling Valve

Low Oil Pressure SwitchOil Temperature SensorOil Level SensorOil Pressure Relief Valve

Pilot Fuel InjectorsMain Fuel InjectorsInlet Guide Vane ActuatorBleed Control ValveCompressor Discharge SensorCooling Fan Assembly

AC Generator PadFuel and Oil PipesCombustor Chamber Drain Valve





Oil CoolerFuel Control UnitFuel Filter ElementFlow Divider AssemblyPilot Manifold Assembly

Main Manifold Assembly

COOLING FAN

ASSEMBLY

STARTER

ENGINEHARNESS

OIL COOLER

IGNITIONEXCITER





LEFT FRONT-TOP VIEW

HARNESS

FUEL CONTROLUNIT

DE-OILINGVALVE

IDENTIFICATIONMODULE

INLET GUIDEVANE

ACTUATOR

BLEEDCONTROLVALVE

COMPRESSORDISCHARGE






RIGHT FRONT TOP VIEW

DISCHARGE MOUNTING PADSENSOR

OILLEVELSENSORSPEED

SENSOR

SWITCHINDICATORS

GENERATORSCAVENGEFILTER

O




MAGNETICDRAIN PLUG

LUBRICATIONFILTER

OIL PRESSUREREIEF VALVE

RIGHT FRONT BOTTOM VIEW


THERMOCOUPLE

IGNITORCABLES

SPEED

FUELFILTER

PILOTMANIFOLD

ASSEMBLY

IGNITOR

FUEL FLOWDIVIDER

ASSEMBLY

MAINMANIFOLD

ASSEMBLY




OIL TEMPERATURESENSOR

SENSOR

LEFT REAR BOTTOM VIEW


AIR INLET ANDTEMPERATURESENSOR

LOW OILPRESSURE SWITCH

NOTE:




NOTE:(The switch may alsobe Located on thelower right side ofthe gearbox)

RIGHT REAR TOP VIEW


THEMOCOUPLE

IGNITOR

COMBUSTORDRAIN CHECKCHECK VALVE

MAIN FUELINJECTOR




PILOT FUELINJECTOR

AIR INLET ANDTEMPERATURESENSOR

RIGHT REAR BOTTOM VIEW


APS 3200


SECTION 12

FAULT ISOLATION

VERSION 6.0





GENERAL DESCRIPTION

The centralized fault display system (CFDS) provides electronicsystem fault detection, fault storage, fault displays, operationaltesting and troubleshooting from the flight deck multi-purpose controland display unit (MCDU).

CENTRALIZED FAULT DISPLAY AND INTERFACE UNIT

The CFDIU provides the interface between the APU electronic

control box (ECB) and the MCDU for screen display of APU faultinformation.


The Multipurpose Control and Display Unit (MCDU) is a display unitand a keyboard used by the CFDS to display and interrogate faultsand to initiate system tests. Both MCDU's (Multipurpose Control andDisplay Unit) are connected to the CFDS.


CFDIU/PRINTER INTERFACE

The CFDIU sends MCDU screen information and print commands tothe optional printer automatically or on request.

CFDIU/ACARS INTERFACE

The CFDIU sends fault information to the optional ACARS for down-linking when selected manually by the MCDU operator or when anuplink request is received from a ground station via the ACARS

management unit.





MCDU - 2

MCDU - 1




CENTRALIZED FAULT DISPLAY SYSTEM


APU FAULT WARNINGS

Flight Deck Fault Warnings are identified as Class 1, 2 and 3.

Class 1 faults are further identified as Level 3, 2 and 1.

CLASS 1

- Level 3- This level corresponds to warnings needing immediate

action.- Level 3 warnings are associated with:

- Repetitive chime- Warning message on upper ECAM display- Master Warning Light flashing Red - APU systems page on lower ECAM display

- Level 2- This level corresponds to abnormal situations needing

immediate awareness but not immediate action.- Level 2 warnings are associated with:

- Single chime- Master caution steady Amber light- Warning messages on upper ECAM display

- APU system page on lower ECAM displayLevel 1

- This level corresponds to reduced bleed air performance- It is associated with low or zero duct pressure- Low or zero duct pressure is visible (lower ECAM display) on

CLASS 2

- These failures are indicated on the STATUS page, under the titleof MAINTENANCE.

- They are also accessible through the CFDS.

indicates that the STATUS page is not empty andflashes in flight phase 10 on the upper ECAM display.STS

CLASS 3

- These failures are only accessible through the CFDS. No APUfault warnings are displayed.





p ( p y)the engine system page during MES or on the APUsystem page.




APU FAULT WARNINGS


APU FAULT WARNINGS

STATUS

STATUS (STS) indication is an "attention getter" on the upper ECAMdisplay.

STATUS (STS) indicates that a status message (class 1 or class 2fault) is present and further maintenance action may be required. Aflashing STS indication occurs after the second engine shutdown inFlight Phase 10. It is necessary to press the STS key on the ECAMcontrol panel for the STATUS page to appear on the lower ECAMdisplay.








UPPER ECAM ADVISORY AND STATUS DISPLAY


APU FAULT WARNINGS

ECAM CONTROL PANEL

The control panel allows selection of the aircraft system pageincluding APU. Pressing the Status (STS) key presents the STATUSpage on the lower ECAM display. The STATUS page will indicate thefaulty aircraft systems under the INOP SYS (Class 1 Fault) andMAINTENANCE (Class 2 Fault) titles.












The Multipurpose Control and Display Unit (MCDU) is a display unit

and a keyboard used by the CFDS to display and interrogate faultsand to initiate system tests. Both MCDU's (Multipurpose Control andDisplay Unit) are connected to the CFDS.


Pressing the MCDU MENU key, the MCDU menu page is displayed,and any one of the systems connected to the MCDU can beselected.

A multiple page display is indicated by an arrow (∇) in the right uppercorner of the screen. In this case the NEXT PAGE key must be usedto provide access to the various pages of the display. The NEXTPAGE key can be used as long as the arrow is displayed.

Twelve line select keys, six on the left and six on the right, provideaccess to a page or a function. The line select keys permit access toa page or a function when these prompt symbols appear (>, <). Theyare identified as 1L to 6L on the left, and 1R to 6R on the right.

If a flight deck printer is installed and operational, the current MCDUdisplay screen may be printed by pushing the PRINT line select key.

APU FAULT OPERATION

SYSTEM SELECTION

The MCDU MENU page is displayed when the MCDU MENU key ispushed.

Selecting the CFDS line select key will then display CFDS menu.

Pressing the SYSTEM REPORT/TEST line select key displays theSYSTEM REPORT TEST menu.








MULTIPURPOSE CONTROL AND DISPLAY UNIT


APU FAULT OPERATION

SYSTEM REPORT/TEST

When SYSTEM REPORT/TEST is selected while on the ground, asystems menu is displayed. The APU selection is located on thesecond page of the menu. Pushing the NEXT PAGE key will display

APU.

Selection of the RETURN line select key on the first page will displayMCDU MENU.

Selection of the RETURN line select key on the second page willdisplay the first page of SYSTEM REPORT/ TEST.

APU

There are two APU menu pages available. The first page displaysthe following information:

LASTLEGREPORT

PREVIOUSLEGREPORT

LRUIDENTIFICATION

SYSTEMSELF-TEST

SHUTDOWNS

The second page of the APU menu when selected by theNEXTPAGE key, displays the following information:

APUDATA/OIL

CLASS3FAULTS

Selection of the RETURN line select key on the First Page willdisplay the Second Page of SYSTEM REPORT/TEST.Selection of the RETURN line select key on the (Second Page) willdisplay the (First Page) of APU menu.





d sp ay t e ( st age) o U e u



HSPS CT/NOV. 2006 Page 12.12O SUNDSTRAND PROPRIETARYHAMILT


APU FAULT OPERATION

APU LAST LEG REPORT

The Last Leg Report displays fault information delivered by theCFDS system. It can store up to 40 failures during the Last Leg. TheLast LEG Report displays only class 1 and 2 faults and contains theidentity of each LRU, its corresponding Date, GMT, ATA chapter andFault Code Number (FCN) for each fault occurrence. The FunctionalIdentification Number (FIN) appears after each LRU. In the case ofmultiple failures, the failures will be displayed in chronological orderwith two failures per page. A maximum count of four intermittentfaults will only be displayed in the same flight leg. Prompts (>) at the

end of each LRU message indicate the line select key to display the APU FAULT CONDITIONS screen. All of the Last Leg Report isprinted when the PRINT line select key is pushed, even if it containsseveral pages.


APU PREVIOUS LEGS REPORT

The Last Leg Report contents are transferred into the Previous LegReport with each new flight leg. The report can store up to 200failures over the last 63 flight legs. Each LRU is identified along withthe Aircraft identification, Leg number, Date, GMT, ATA chapter andFault Code Number (FCN) for each fault occurrence. The FunctionalIdentification Number (FIN) appears after each LRU. In the case ofmultiple failures, the failures will be displayed in reversechronological order with two failures per page. Prompts (>) at theend of each LRU message indicate the line select key to display the

APU FAULT CONDITIONS screen. Only the PREVIOUS LEGSREPORT displayed page will be printed when the PRINT line selectkey is pushed.






APU LAST LEG REPORT APU PREVIOUS LEGS REPORT





APU FAULT OPERATION

APU LRU IDENTIFICATION

The LRU Identification page displays the ECB Part Number, ECBSerial Number and the ECB Software Version.

The ECB part number is adjustable and is stored in the NVM. Thebuilt letter (H) following the part number is adjustable from A to Z.


APU SYSTEM SELF TEST

A self test of LRU's may be initiated through the CFDS. The test canonly be accomplished when the APU is not running and the MasterSwitch is ON. In case of no failures or when the test is in progress, orlack of availability of the test function, the message of TEST OK, INPROGRESS and NOT AVAILABLE will be displayed respectively.Detected failures will be displayed with their ATA Chapter and FaultCode Number (FCN). The Functional Identification Number (FIN)appears after each LRU. In the case of multiple failures, the failureswill be displayed in chronological order with two failures per page.

Only the SYSTEM SELF TEST displayed page will be printed whenthe PRINT line select key is pushed.










APU FAULT OPERATION

APU SHUTDOWNS

The Shutdowns page contains its corresponding Date, GMT, FaultCode Number (FCN), shutdown message and the identity of theLRU. The Shutdowns will be displayed in reverse chronological orderwith only one shutdown per page. Prompts (>) at the end of eachLRU message indicate the line select key to display the APU FAULTCONDITIONS screen.

In case there are no shutdowns, the message of NO SHUTDOWNSwill be displayed. Only the SHUTDOWNS displayed page will be

printed when the PRINT line select key is pushed.


APU DATA/OIL

APU Data/Oil page contains the Date, APU Serial Number (S/N),Hours, Start Attempts, Start Cycles and Oil level status. Prompts (>)at the end of the message indicate the line select key to display the"Update APU Data" screen.










APU FAULT OPERATION

APU CLASS 3 FAULTS

Class 3 Faults can be stored up to 200 failures over the last 63 flightlegs. Each LRU is identified along with the Aircraft identification, Legnumber, GMT, ATA chapter and Fault Code Number (FCN) for eachfault occurrence. The Functional Identification Number (FIN) appearsafter each LRU. In the case of multiple failures, the failures will bedisplayed in reverse chronological order with two failures per page.Prompts (>) at the end of each LRU message indicate the line selectkey to display the APU FAULT CONDITIONS screen.

In case there are NO CLASS 3 FAULTS detected, the message NOFAULTS will be displayed. Only the CLASS 3 FAULTS displayedpage will be printed when the PRINT line select key is pushed.










APU FAULT OPERATION

UPDATE APU DATA

Selection of this screen allows the operator to update the APU hoursand cycles when the ECB or the APU is changed.The Update APU Data screen is only accessible by prompts (>) fromthe APU Data/Oil Screen. The Update APU Data screen displays the

APU Serial Number (S/N), and current values of Hours and Cycles.The new values of hours and cycles can be entered by use of MCDUkeyboard. After line key 3L is pressed (Prompt <) the screen willdisplay the new values for APU hours and cycles when the ECB or

APU is changed.

The HOURS and CYCLES will be printed when the PRINT line selectkey is pushed.

Selection of the RETURN line select key will display the APUDATA/OIL screen.









APU FAULT OPERATION

FAULT CONDITIONS

The Fault Conditions screens are only available by the line selectkeys indicated by prompt (>) on the Last Leg Report, Previous LegsReport, Shutdown and Class 3 fault screens. Selection will displaythe Fault Conditions screen-1 or screen-2. Each screen will displaythe APU S/N, Date, GMT and the identity of the LRU. The FunctionalIdentification Number (FIN) appears after the LRU.Engine data from the fault data stored in the Electronic Control Boxnon-volatile memory will also appear on each screen. (See Screen-1and Screen-2 Parameters on page 12-24).

One screen at a time is displayed. To select screen-2 when screen-1is displayed or select screen-1 when screen-2 is displayed it isnecessary to press the NEXT PAGE key on the Multipurpose Controland Display Unit (MCDU).

Only the screen that is displayed (Screen-1 or Screen-2) will beprinted when the PRINT line select key is pushed.

Selection of the RETURN line select key will display the screen thatwas shown preceding selection of the Fault Selection Screens.









FLIGHT DECK PRINTER

The Printer provides onboard printouts concerning various aircraftsystems, one at a time.

MANUAL PRINT

In manual mode, prints of the MCDU screen display are printedwhen the PRINT line select key is pushed.

AUTOMATIC PRINT

In flight phase 10, the Post Flight Report will be automatically

printed. The Post Flight Report is the sum of the LAST LEGREPORT and the LAST LEG ECAM REPORT.

A list of ECAM Warnings and Fault Messages with the associatedtime and ATA chapter references are provided on the printed tape.








FLIGHT DECK PRINTER


FAULT CHARTS

The following Fault Charts provide the information that will be sent tothe CFDS by the ECB in the event of a fault.

The information appears in the Fault Chart columns located underthe following headings:

Version 5.0

MCDU LRU MessageMCDU Shutdown MessageFault CodeFault Class

LRU ID ATA ChapterSystem Severity level


System Severity Levels are not sent to the CFDS. It is presentedhere only as information.

Once a fault has been identified with a switch or a sensor thatcomponent will no longer be used for further fault detection, isolationor control until the fault is no longer present. Detected faults can becleared and a restart may be possible once the master switch iscycled.

SYSTEMSEVERITY LEVEL ECB ACTION ECB MESSAGE



3 SHUTDOWN IF REDUNDANTSOURCE NOT AVAILABLE

TRANSMIT FAULTMESSAGE

4 CONTINUE TO OPERATE TRANSMIT FAULTMESSAGE

X NOT APPLICABLE





P OWE R U

P

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S

T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


BLD FLOW XDCR (8039KM) 0 1 13 495112 4 4 4 4 4 4 4 4

BLD FLOW XDCR (8039KM) 1 1 13 495112 4 4 4 4 4 4 4 4

COOLING FAN PMG ASSY (8055KM) 2 1 53 495253 X X X 4 4 4 4 X

BLD FLOW XDCR (8039KM) 3 1 13 495112 4 4 4 4 4 4 4 4

INLET T-P SNSR (8013KM) 4 1 29 492317 4 4 4 4 4 4 4 4

INLET T-P SNSR (8013KM) 5 1 29 492317 4 4 4 4 4 4 4 4

INLET T-P SNSR (8013KM) 6 1 29 492317 4 4 4 4 4 4 4 4

(BLANK) 7

INLET T-P SNSR (8013KM) 8 1 29 492317 4 4 4 4 4 4 4 4

INLET T-P SNSR (8013KM) 9 1 29 492317 4 4 4 4 4 4 4 4

GENERATOR (8XS) 10 3 25 242351 3 3 3 3 3 3 3 3

GENERATOR (8XS) 11 3 25 242351 3 3 3 3 3 3 3 3

OIL TEMP SNSR (8084KM) 12 3 38 499151 3 3 3 3 3 3 3 3

OIL TEMP SNSR (8084KM) 13 3 38 499151 3 3 3 3 3 3 3 3

ECB (59KD) 14 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 15 3 14 496134 4 4 4 4 4 4 4 4





HSPS CT/ NOV. 2006 Page 12.28HAMILTON SUNDSTRAND PROPRIETARY




P OWE R U

P

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S

T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER






EXCITER SHORTED 23 1 26 494138 X X X 4 X X X X

ECB (59KD) 24 2 14 496134 4 4 4 4 4 4 X 4



ECB (59KD) 27 3 14 496134 4 4 X X X X 4 4

ECB (59KD) 28 3 14 496134 3 3 3 3 3 3 3 3

SPEED SNSR1 (8060KM1) 29 3 40 497113 X X 3 3 3 3 3 X

ECB (59KD) 30 3 14 496134 X X X 3 3 3 X X

ECB (59KD) 31 3 14 496134 3 3 3 3 3 3 3 3

SPEED SNSR2 (8060KM2) 32 3 42 497113 X X 3 3 3 3 3 X

SPEED SNSR1 (8060KM1) ANDSPEED SNSR2 (8060KM2)

LOSS OF SPEED 33 1 44 497113 1 1 1 1 1 1 1 1

(SPEED SENSORS DO NOT MATCH - NO TEXT) 34 3 NO TEXT 4 4 4 4 4 4 4 4

EGT TC1 (8075KM1) 35 3 15 497215 X X X 3 3 3 X X





EGT TC1 (8057KM1) 36 3 15 497215 3 3 3 3 3 3 3 3

P OWE R U

P

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S

T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


EGT TC2 (8057KM2) 37 3 18 497215 X X X 3 3 3 X X

EGT TC2 (8057KM2) 38 3 18 497215 3 3 3 3 3 3 3 3

GEN SCAN FILTER (8069KM) ANDLUB FILTER (8076KM)

39 2 7 499141 4 4 4 4 4 4 4 X

- LOSS OF DC POWER 40 1 - - X X X 1 1 1 X X


IGNITION UNIT (8030KM) NO FLAME 42 1 26 494138 X X X 1 X X X X

ECB (59KD) NO FLAME 42 1 14 496134 X X X 1 X X X X

FUEL CONTROL UNIT (8022KM) NO FLAME 42 1 21 493211 X X X 1 X X X X

CHECK APU FUEL SUPPLY NO FLAME 42 1 70 282200 X X X 1 X X X X

IGNITION UNIT (8030KM)FUEL CONTROL (8022KM)

NO FLAME 42 1 27 494138 X X X 1 X X X X

OIL PRESS SW (8091KM) 43 2 36 499414 4 4 X X X X X 4



CHECK OIL COOLER ASSY HIGH OIL TEMPERATURE 46 1 9 499144 X X X 2 2 2 X X

CHECK OIL SYSTEM/GENERATOR (8XS) GEN HIGH OIL TEMP 47 1 24 499100 X X X 2 2 2 X X

LOW OIL LEVEL 48 2 32 499300 4 4 X X X X X 4








P OWE R U

P

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S

T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


ACFT BAT NOT SELECTED/CONTACTOR (5KA) NO ACCELERATION 51 1 11 243800 X X X 1 X X X X



CURRENT LIMITER (6KA)/CONTACTOR (10KA) NO ACCELERATION 51 1 51 494200 X X X 1 X X X X

STATOR MOTOR (8KA)/STARTERCLUTCH

(8033KM)




CHECK APU FUEL SUPPLY NO ACCELERATION 52 1 70 282200 X X X 1 X X X X

FUEL CTL UNIT (8022KM)/FLOW DIVIDER(8024KM)




DE-OILING SOL (8083KM) NO ACCELERATION 53 1 12 499149 X X X 2 X X X X

IGV ACTR (8014KM) NO ACCELERATION 53 1 28 492351 X X X 2 X X X X

STARTER MOTOR (8KA)/BLD CTL VLV (8051KM) NO ACCELERATION 53 1 46 494251 X X X 2 X X X X

FLOW DIVIDER (8024KM) NO ACCELERATION 53 1 68 493213 X X X 2 X X X X

FLOW CTL UNIT (8022KM) NO ACCELERATION 53 1 21 493211 X X X 2 X X X X

ECB (59KD) 54 3 14 496134 4 X X X X X X 4





ECB (59KD) 54 3 14 496134 4 X X X X X X 4

ECB (59KD) 55 3 14 496134 4 X X X X X X 4

P OWE R U

P

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S

T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


ECB (59KD) 56 3 14 496134 4 X X X X X X 4

INLET FLAP ACTR (4015KM) 57 2 2 491651 4 4 4 4 4 4 4 4

INLET FLAP ACTR (4015KM) 58 2 2 491651 X 4 4 4 X X 4 4



ECB (59KD) ECB FAILURE 61 1 14 496134 X X X 2 2 2 X X



ECB (59KD) 64 2 14 496134 X X X X 4 X X X

(BLANK) 56

ECB (59KD) 66 2 14 496134 X X X X 4 X X X

ECB (59KD) UNDERSPEED 67 1 14 496134 X X X X 1 1 X X

CHECK APU FUEL SUPPLY UNDERSPEED 67 1 70 282200 X X X X 1 1 X X

FUEL CTL UNIT (8022KM) UNDERSPEED 67 1 21 493211 X X X X 1 1 X X


OVERSPEED 68 1 44 497113 X X X 1 1 1 X X

ECB (59KD) OVERSPEED 68 1 14 496134 X X X 1 1 1 X X

FUEL CTL UNIT (8022KM) OVERSPEED 68 1 21 493211 X X X 1 1 1 X X

C ( )






P OWE R U

P

WA T C H

S T A RT P RE P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S

T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER



ECB (59KD) 71 1 14 496134 X X X X 4 X X X

(BLANK) 27

ECB (59KD) 73 2 14 496134 X X X X 4 X X X

ECB (59KD) ECB FAILURE 74 1 14 496134 1 X X X X X X X

ECB (59KD) 75 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 76 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 77 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 78 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 79 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 80 3 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 81 3 14 496134 4 X 4 4 4 4 X 4

ECB (59KD) 82 2 14 496134 4 4 4 4 4 4 4 4

ECB (59KD) 83 3 14 496134 4 4 4 4 4 4 4 4


ACFT BAT NOT SELECTED/CONTACTOR (5KA)

85 1 11 243800 X X X 4 X X X X


WRG ECB PIN AB H9 87 3 45 496100 X X X 4 X X X X






P OWE R U

P

WA T C H

S T A RT P RE

P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S

T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER





IGNITION UNIT (8030KM) 91 1 26 494138 X X X 4 X X X X

SPEED SNSR1 (8060M1) 92 3 40 497113 3 3 3 3 3 3 3 3

SPEED SNSR1 (8060M1) 93 3 40 497113 3 3 3 3 3 3 3 X

SPEED SNSR2 (8060KM2) 94 3 42 497113 3 3 3 3 3 3 3 3

SPEED SNSR2 (8060KM2) 95 3 42 497113 3 3 3 3 3 3 3 X



IGV ACTR (8014KM) OVERTEMPERATURE 98 1 28 492351 X X X 2 2 2 X X



FUEL CTL UNIT (8022KM) OVERTEMPERATURE 98 1 21 493211 X X X 2 2 2 X X

FUEL CTL UNIT (8022KM) 99 1 21 493211 X X X X X X 1 X

ECB (59KD) 100 2 14 496134 3 X X X X X X 3

ECB (59KD) 101 2 14 496134 3 X X X X X X 3

EGT TC1 (8057KM1) ANDEGT TC2 (8057KM2)

SENSOR FAILURE 102 1 16 497215 2 2 2 2 2 2 2 2





EGT TC2 (8057KM2)

P OWE R UP

WA T C H

S T A RT P RE

P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


BLD FLOW XDCR (8039KM) 103 1 13 495112 4 4 4 4 4 4 4 4



NO DATA FROM ECS 106 3 34 216334 X X X X 4 X X X

ECB (59KD) 107 2 14 496134 X 4 4 4 4 4 4 4





FUEL LOW PRESS/LOW FUEL PRESS SW(5030QM)

112 2 31 282214 X X X 4 4 4 X X

- EMERGENCY STOP 113 1 NO TEXT - 1 1 1 1 1 1 1 1


ECB (59KD) BACKUP OVERSPEED 115 1 14 496134 X 1 1 1 1 1 1 1


BACKUP OVERSPEED 115 1 44 497113 X 1 1 1 1 1 1 1

FUEL CTL UNIT (8022KM) BACKUP OVERSPEED 115 1 21 493211 X 1 1 1 1 1 1 1

COOLING FAN PMG ASSY (8055KM) BACKUP OVERSPEED 115 1 53 495253 X 1 1 1 1 1 1 1

ECB (59KD) BACKUP OVERSPEEDCIRCUIT FAILURE

116 1 14 496134 1 X X X X X X X





CIRCUIT FAILURE

P OWE R UP

WA T C H

S T A RT P RE

P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


ECB (59KD) 117 1 14 496134 4 X X X X X X 4


IGV ACTR (8014KM) 118 1 28 492351 X X X X 4 4 4 X


BLEED CTL VLV (8051KM) 119 1 5 495153 X X X X 4 4 4 X

INLET FLAP ACTR (4015KM) 120 2 2 491651 X X X X X X 4 X

INLET FLAP ACTR (4015KM) AIR INTAKE NOT OPEN 121 1 2 491651 X 1 1 X X X X 1

OIL TEMP SNSR (8084KM) AND GENERATOR(8XS)`

SENSOR FAILURE 122 1 50 499151 2 2 2 2 2 2 2 2

ECB (59KD)/APU HARNESS (8001KM) 123 1 8 496134 4 4 4 4 4 4 4 4

WRG: ACFT TYPE PIN/FCB (59KD) 124 3 47 496100 4 X X X X X X X

WRG: ECB PIN AB-H5 125 3 4 496100 4 4 4 4 4 4 4 4

CURRENT LIMITER (6KA)/CONTACTOR (10KA) 126 1 51 494200 X X X 4 X X X X





(BLANK) 131

ECB (59KD) ECB FAILURE 132 1 14 496134 1 X X X X X X 1





( )

P OWE R UP

WA T C H

S T A RT P RE

P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


FIRE EMERG-STOP RELAY (6WF) 133 3 54 262200 X X X X X X 4 X

FIRE EMER STOP RELAY (6WF) 134 3 54 262200 X X X X X X 4 X

ECB (59KD) 135 3 14 496134 X 4 4 4 4 4 4 X

(EMERGENCY STOP TEST - NO TEXT) 136 3 NO TEXT - 4 4 X X X X X X

(BLANK) 137

BLEED CTL VLV (8051KM) 138 1 5 495153 X X X 4 X X X X

IGV ACTR (8014KM) 139 1 28 492351 X X X 4 X X X X

OIL PRESS SW (8091KM) AND OIL LVL SNSR(8089KM)

SENSOR FAILURE 140 1 55 499414 2 2 X X X X X 2

OIL PRESS SW (8091KM) AND LOW OIL LEVEL SENSOR FAILURE 141 1 56 499414 2 2 X X X X X 2

ECB (59KD) LOSS OF SPEED 142 1 14 496134 1 1 1 1 1 1 1 1





(BLANK) 147

(BLANK) 148

BLD FLOW XDCR (8039KM) 149 1 13 499112 X X X 4 4 4 4 X






P OWE R UP

WA T C H

S T A RT P RE

P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER
















ECB (59KD) 165 3 14 496134 4 4 4 4 4 4 4 X

ECB (59KD) 166 3 14 496134 X 4 4 4 4 4 4 X


ECB (59KD) APU FUEL VALVE FAILED OPEN 168 1 14 496134 X 1 X X X X 1 X





P OWE R UP

WA T C H

S T A RT P RE

P

S T A RT I N G

R UN

C O OL D OW

N

S H UT D OW

N

S E L F T E S T

MCDULRU

MESSAGE

MCDUSHUTDOWNMESSAGE

FAULTCODE

FAULTCLASS

LRUID

ATACHAPTER


BLD FLOW XDCR (8039KM)/BLD CTL VLV (8051KM)

169 1 48 495112 X X X X 4 4 X X

INLET T-P SNSR (8013KM) 170 1 29 492317 4 4 4 4 4 4 4 4

BLD FLOW XDCR (8039KM) 170 1 13 495112 4 4 4 4 4 4 4 4

BLD FLOW XDCR (8039KM) 171 1 13 495112 X X X X 4 X X X



BLEED CTL VLV (8051KM)/FUEL CTL UNIT (8022KM)

174 1 69 495153 X X X X 4 X X X






SECTION 13

TROUBLESHOOTING





TROUBLESHOOTING

GENERAL

The troubleshooting system is designed to provide additionalinformation to aid in the maintenance and repair of the AuxiliaryPower Unit (APU) by downloading the Electronic Control Box (ECB)located in the aircraft aft cargo compartment.Maintenance information is stored in the nonvolatile memory of theECB and can be retrieved and analyzed by downloading into alaptop computer. The computer displays information andrecommended actions from the following stored data:

CONDITIONING MONITORING DATA

This data consists of engine parameters taken at each engine startand shutdown. Data is provided for the last twelve engine run cycles.

FAULT DATA

The data consists of maintenance and fault messages for class 1,class 2 faults and class 3 faults.

REQUIRED HARDWARE

Downloading of the ECB requires the following equipment:

Laptop computer or Personal Computer (PC) with at least3MB of free hard disc space, a modem and a Windows 95 orlater operating system.

A special interface cable is required to connect theComputer to the ECB. The interface cable (P/N AGE 70021)is available by contacting Hamilton Sundstrand.









TROUBLESHOOTING


To download and diagnose fault data, refer to APIC SIL APS32-0049-47 for in-depth instructions.

Basic Steps:• Connect the interface cable from the computer to the ECB.• Power-up computer.• Select Diagnose on the tool bar.• Enter operators name on the Setup screen.• APU master switch ON (APU not running.)

• Select Continue on the Setup screen.









TROUBLESHOOTING


ECB TROUBLESHOOTING AID (Fault Information)

The computer screen displays Class 1, Class 2 faults and Class 3faults. The screen will download and provide a file automatically forreview. (See example on page 13.6.)

Select the Most Recent scroll bar on the screen to scroll through thevarious faults.Each fault or fault combination is provided with a fault description

and recommended action.









TROUBLESHOOTING


REAL-TIME DATA MONITORING

With the Real-Time Data monitoring screen displayed, select AnalogI/O, Speed/Temp, or Discreet Inputs. Each selection displays ascreen that provides real time data. The data is viewed at the bottomof the screen when a data box is selected.

Note: The more data boxes selected the longer it takes for theinformation to appear. Select data that is related to the

specific fault for a faster response time.

BASIC STEPS:• Connect the interface cable from the computer to the ECB.• Power-up computer.• Start and run APU.• Select data box.• Select Start Monitoring.• Select Stop Monitoring after data has been taken.

Selecting Save Data at the bottom of the screen and selecting a filename allows the data to be saved. (See page 13.9 and example onpage 13.10.)









TROUBLESHOOTING


SNAPSHOT VIEW

BASIC STEPS:

• Select Snapshot with the APU operating• Select Analog Inputs.• Select Discrete Inputs.• Click on Take Snapshot. (This will provide one quick view

of data)





HSPS CT/NOV 2006 P 13 10HSPS CT/NOV 2006 P 13 10













Documents

Aps 3200 Training