DOC AIRBUS | AMM A320FAIRBORNE AUXILIARY POWER - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
A. Function of the Auxiliary Power System
In order to permit A/C ground operation independent of electric and pneumatic ground power, the A/C is equipped with an auxiliary power system. The A/C thus can be powered up autonomously, allowing the operator to service airports without adequate ground power facilities.
In-flight availability of the auxiliary power system permits A/C operation under MMEL-conditions and under ETOPS.
In order to permit A/C ground operation independent of electric and pneumatic ground power, the A/C is equipped with an auxiliary power system. The A/C thus can be powered up autonomously, allowing the operator to service airports without adequate ground power facilities.
In-flight availability of the auxiliary power system permits A/C operation under MMEL-conditions and under ETOPS.
B. System Functions
The gas turbine engine (the APU), which is used as the systems power source, is equipped to supply 115VAC for operation of the A/C electrical systems. It also supplies pneumatic power to let main engine start (MES) and environmental control system (ECS) operations.
The gas turbine engine (the APU), which is used as the systems power source, is equipped to supply 115VAC for operation of the A/C electrical systems. It also supplies pneumatic power to let main engine start (MES) and environmental control system (ECS) operations. The APU can also do the Integrated Controlled APU to Rotate Engine (iCARE) operation, used for the cooling of the engines before the MES.
The gas turbine engine (the APU), which is used as the systems power source, is equipped to supply 115VAC for operation of the A/C electrical systems. It also supplies pneumatic power to let main engine start (MES) and environmental control system (ECS) operations.
The gas turbine engine (the APU), which is used as the systems power source, is equipped to supply 115VAC for operation of the A/C electrical systems. It also supplies pneumatic power to let main engine start (MES) and environmental control system (ECS) operations. The APU can also do the Integrated Controlled APU to Rotate Engine (iCARE) operation, used for the cooling of the engines before the MES.
C. APU Supplier
The APU, fully designated 131-9 (A), is supplied by the AlliedSignal Aerospace Company - Engines.
The APU, fully designated 131-9 (A), is supplied by the AlliedSignal Aerospace Company - Engines.
2. Component Location
B. Cockpit
C. Avionics Compartment/Aft Cargo Compartment
Auxiliary Power System - Component Location (Avionics Compartment/Aft Cargo Compartment) ** ON A/C NOT FOR ALL
Auxiliary Power System - Component Location (Avionics Compartment/Aft Cargo Compartment) ** ON A/C NOT FOR ALL 3. System Description
A. Power Plant (Ref. 49-10-00)
The power plant is installed in the rear fuselage aft of the passenger compartment. It occupies the tailcone, the rearmost portion of the fuselage. The tailcone has been fitted with a fireproof compartment to house the APU. Peripheral systems are installed both in the APU compartment as well as to the front and rear of it. Doors permit access to all components of the power plant.
The power plant is installed in the rear fuselage aft of the passenger compartment. It occupies the tailcone, the rearmost portion of the fuselage. The tailcone has been fitted with a fireproof compartment to house the APU. Peripheral systems are installed both in the APU compartment as well as to the front and rear of it. Doors permit access to all components of the power plant.
B. Engine (Ref. 49-20-00)
The engine supplies:
The engine supplies:
- pneumatic power,
- electrical power, and
- cooling air.
C. Engine Fuel and Control (Ref. 49-30-00)
The APU system receives fuel from the A/C APU fuel supply system (Ref. 28-22-00). Incoming fuel is metered by the fuel control unit (FCU) and delivered to the flow divider assy. From there it is routed via 2 fuel manifolds to the fuel nozzles, located in the combustion chamber.
The APU system receives fuel from the A/C APU fuel supply system (Ref. 28-22-00). Incoming fuel is metered by the fuel control unit (FCU) and delivered to the flow divider assy. From there it is routed via 2 fuel manifolds to the fuel nozzles, located in the combustion chamber.
D. Ignition and Starting (Ref. 49-40-00)
The APU is fitted with a DC starter motor, which draws its power from the electrical system battery bus. It turns the engine to such speed that self-sustained engine operation becomes possible. The fuel-air mixture in the combustion chamber is ignited by the ignition system, also fitted to the APU. Electrical power to the ignition system is supplied through the ECB.
The APU is fitted with a DC starter motor, which draws its power from the electrical system battery bus. It turns the engine to such speed that self-sustained engine operation becomes possible. The fuel-air mixture in the combustion chamber is ignited by the ignition system, also fitted to the APU. Electrical power to the ignition system is supplied through the ECB.
E. Air (Ref. 49-50-00)
The engine gives 2 air sources that are not connected:
The engine gives 2 air sources that are not connected:
- pneumatic power (bleed air) for main engine start (MES) and the environmental control system (ECS),
- cooling air for ventilation of the APU compartment and cooling of the APU lubrication system.
- pneumatic power (bleed air) for main engine start (MES), the environmental control system (ECS) and the Integrated Controlled APU to Rotate Engine (iCARE),
- cooling air for ventilation of the APU compartment and cooling of the APU lubrication system.
F. Engine Controls (Ref. 49-60-00)
In order to start, control its performance and to shut off the auxiliary power system, manual and automatic controls are provided.
Manual control of the APU is possible through the crew interfaces in the cockpit. Automatic control is accomplished through the ECB.
In order to start, control its performance and to shut off the auxiliary power system, manual and automatic controls are provided.
Manual control of the APU is possible through the crew interfaces in the cockpit. Automatic control is accomplished through the ECB.
G. Indicating (Ref. 49-70-00)
The ECB monitors the operation of the auxiliary power system. It transmits operation information to the A/C indicating and recording systems ECAM, CFDS and AIDS. It also records system faults in its internal memory. Display of subject data is in the cockpit on the CFDS monitor.
The ECB monitors the operation of the auxiliary power system. It transmits operation information to the A/C indicating and recording systems ECAM, CFDS and AIDS. It also records system faults in its internal memory. Display of subject data is in the cockpit on the CFDS monitor.
H. Exhaust (Ref. 49-80-00)
The APU exhaust system serves to duct the engine exhaust overboard. Its secondary purpose is to reduce the exhaust noise level. In order to minimize aerodynamic losses during APU operation, the duct is designed sufficiently large in diameter. Also, exhaust discharge takes place at the very aft end of the A/C, where a low pressure area exists during flight. Thus it is also assured that exhaust gas does not re-enter the APU air intake system.
The APU exhaust system serves to duct the engine exhaust overboard. Its secondary purpose is to reduce the exhaust noise level. In order to minimize aerodynamic losses during APU operation, the duct is designed sufficiently large in diameter. Also, exhaust discharge takes place at the very aft end of the A/C, where a low pressure area exists during flight. Thus it is also assured that exhaust gas does not re-enter the APU air intake system.
I. Oil (Ref. 49-90-00)
The APU oil system lubricates and cools the power section, load compressor, gearbox and AC-Generator. This system is made up of:
The APU oil system lubricates and cools the power section, load compressor, gearbox and AC-Generator. This system is made up of:
- an integral wet-sump lubrication system with an APU mounted oil cooler,
- an oil level, high oil temperature and low oil-pressure monitoring system.
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5. Interface
A. Fuel Supply
Fuel is supplied to the APU by the A/C APU fuel supply system (Ref. 28-22-00 and 28-29-00).
Fuel is supplied to the APU by the A/C APU fuel supply system (Ref. 28-22-00 and 28-29-00).
B. Pneumatic Power
Pressurized air generated by the APU is fed into the A/C pneumatic power distribution system (Ref. AMM D/O 36-12-00-00).
Pressurized air generated by the APU is fed into the A/C pneumatic power distribution system (Ref. AMM D/O 36-12-00-00).
C. APU Fire Protection
The APU and most of its peripheral subsystems are installed in the APU compartment, a designated fire zone. This compartment therefore is equipped with a fire detection (Ref. 26-13-00) and fire extinguishing system (Ref. 26-22-00).
The APU and most of its peripheral subsystems are installed in the APU compartment, a designated fire zone. This compartment therefore is equipped with a fire detection (Ref. 26-13-00) and fire extinguishing system (Ref. 26-22-00).
D. Electrical Power
The APU is equipped with a 115VAC electrical power generator, which feeds into the A/C electrical power distribution system (Ref. AMM D/O 24-23-00-00).
The APU is equipped with a 115VAC electrical power generator, which feeds into the A/C electrical power distribution system (Ref. AMM D/O 24-23-00-00).
6. Operation/Control and Indicating
Auxiliary Power System - Operating Envelope/APU Performance ** ON A/C NOT FOR ALL
Auxiliary Power System - Operating Envelope/APU Performance ** ON A/C NOT FOR ALL
The APU system operates independently of the other engine systems, in the conditions of operation shown below:
Auxiliary Power System - Operating Envelope/APU Performance ** ON A/C NOT FOR ALL Auxiliary Power System - Operating Envelope/APU Performance ** ON A/C NOT FOR ALL The APU system operates independently of the other engine systems, in the conditions of operation shown below:
A. Normal Conditions of Operation (APU not essential)
(1) Ground Operation
The APU will:
The APU will:
- Supply bleed air for the main engine start on the ground in an altitude range between -609.6 m (-2000 ft.) and 4602.5 m (15100 ft.) at a temperature of -54 deg.C (-65 deg.F) to 55 DEG.C (131 DEG.F)
- Supply bleed air for the air conditioning of the passenger compartment and the cockpit
- Supply shaft power to a 90 kVA generator when the air conditioning is necessary.
(2) Flight Operation
The APU will:
The APU will:
- Supply bleed air in flight to a maximum altitude of 6096 m (20000 ft.)
- Supply shaft power to a 90 kVA generator.
(3) An electric DC motor starts the APU:
- In ground operation conditions, the aircraft batteries and/or the transformer rectifier units start the APU
- A start in flight is possible to a maximum altitude of 12496.6 m (41000 ft.) if the transformer rectifier units are used. A start in flight is possible to a maximum altitude of 7630 m (25033 ft.) if only the aircraft batteries are used.
(4) Ground Operation
The APU will:
The APU will:
- Supply bleed air for the main engine start and for the iCARE on the ground in an altitude range between -609.6 m (-2000 ft.) and 4602.5 m (15100 ft.) at a temperature of -54 deg.C (-65 deg.F) to 55 DEG.C (131 DEG.F)
- Supply bleed air for the air conditioning of the passenger compartment and the cockpit
- Supply shaft power to a 90 kVA generator when the air conditioning is necessary.
(5) Flight Operation
The APU will:
The APU will:
- Supply bleed air in flight to a maximum altitude of 6096 m (20000 ft.)
- Supply shaft power to a 90 kVA generator.
(6) An electric DC motor starts the APU:
- In ground operation conditions, the aircraft batteries and/or the transformer rectifier units start the APU
- A start in flight is possible to a maximum altitude of 12496.6 m (41000 ft.) if the transformer rectifier units are used. A start in flight is possible to a maximum altitude of 7630 m (25033 ft.) if only the aircraft batteries are used.
B. Operation in Icing Conditions
The APU will safely operate in ground icing conditions and during a subsequent flight in icing conditions, with it operating as an essential unit. It can be started in climb and flight after APU operation in icing conditions on the ground.
The APU will safely operate in ground icing conditions and during a subsequent flight in icing conditions, with it operating as an essential unit. It can be started in climb and flight after APU operation in icing conditions on the ground.
C. Control and Monitoring
The ECB 59KD controls and monitors the APU operation. The Built-In Test Equipment (BITE) of the ECB is connected to the CFDS (Ref. AMM D/O 31-32-00-00). The components that control and monitor the system are divided into two interfaces:
The ECB 59KD controls and monitors the APU operation. The Built-In Test Equipment (BITE) of the ECB is connected to the CFDS (Ref. AMM D/O 31-32-00-00). The components that control and monitor the system are divided into two interfaces:
- Flight Crew Interface,
- Maintenance Interface.
(1) Flight Crew Interface
The APU Flight Crew Interface is made up of different overhead panels, and the ECAM system in the center of the instrument panel.
The APU Flight Crew Interface is made up of different overhead panels, and the ECAM system in the center of the instrument panel.
(a) APU Control Panel 25VU includes:
- the MASTER SW 14KD which energizes the APU circuits and is also used for a manual shutdown of the APU system. Part of the MASTER SW is a blue 'ON' annunciator light and an amber 'FAULT' annunciator light.
- the APU START pushbutton 2KA which controls the APU start. Part of the START switch is a blue 'ON' annunciator light which comes on during the start procedure. The other part consists of a green 'AVAIL' annunciator light which comes on when the APU speed reaches 95 % rpm, and the blue 'ON' annunciator light goes off.
(b) Air conditioning panel 30VU includes:
- the APU BLEED air switch 5HV which opens and closes the bleed load valve. Part of the switch is a blue 'ON' annunciator light and an amber 'FAULT' annunciator light.
(c) Electric panel 35VU includes:
- The APU GEN switch which disconnects the electrical load from the APU generator during operation of the APU. Part of the switch is a white 'OFF' annunciator light and an amber 'FAULT' annunciator light.
(d) Fire panel 20VU includes:
- the APU FIRE pushbutton switch 1WD which starts the APU shutdown procedure when a fire warning is indicated,
- the APU AGENT push switch which operates the fire extinguisher.
- the TEST switch for the continuity test on the APU fire warning loops, and the cartridge, of the fire extinguisher bottle.
(e) The indicating system (Ref. AMM D/O 49-70-00-00) supplies the flight crew with data on the APU system configuration during flight operation. The data is supplied on two display units as memo messages and system diagrams. The system page (lower ECAM display unit) indicates the data shown below:
During satisfactory flight operation, the engine/warning page (upper ECAM display unit) indicates a memo message if no warning is to be shown:
Example of failure mode indicated is:
- speed (rpm) in % of nominal speed (Ref. AMM D/O 49-71-00-00),
- Exhaust Gas Temperature (EGT) in deg. C (Ref. AMM D/O 49-72-00-00),
- APU bleed air pressure in psi and the position of the APU bleed valve (Ref. 49-51-00),
- AVAIL if the APU speed is above 95 % rpm,
- APU generator load in %, voltage (V) and frequency (Hz),
- the air-intake flap open indicator.
- manual mode (pushed APU button on the ECAM control panel),
- flight phase related automatic mode,
- advisory automatic mode,
- failure related automatic mode.
During satisfactory flight operation, the engine/warning page (upper ECAM display unit) indicates a memo message if no warning is to be shown:
- APU AVAIL,
- APU BLEED.
Example of failure mode indicated is:
- APU AUTO SHUT DOWN,
- MASTER SW ... OFF.
(2) Maintenance Interface
Two Multipurpose Control and Display Units (MCDUs) are installed on the center pedestal in the cockpit. The MCDUs are at the front of the center pedestal. This equipment gives access to the APU maintenance information, the APU interfaces with the CFDS and the AIDS.
Two Multipurpose Control and Display Units (MCDUs) are installed on the center pedestal in the cockpit. The MCDUs are at the front of the center pedestal. This equipment gives access to the APU maintenance information, the APU interfaces with the CFDS and the AIDS.
(a) The MCDU displays the defective Line Replacable Units (LRUs) through the CFDS. This is possible in two modes:
- NORMAL mode.
- MENU mode.