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.
J. Oil (Ref. 49-90-00) The APU oil system lubricates and cools the power section, load compressor, gearbox and AC-Generator (8XS). 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. The Electronic Control Box (ECB) (59KD) monitors these parameters.
4. Power Supply____________ (Ref. Fig. 007)
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).
B. Pneumatic Power Pressurized air generated by the APU is fed into the A/C pneumatic power distribution system (Ref. 36-12-00).
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).
D. Electrical Power The APU is equipped with a 110VAC electrical power generator, which feeds into the A/C electrical power distribution system (Ref. 24-23-00).
6. Operation/Control and Operation_______________________________
The APU system operates independently of the other engine systems, in the conditions of operation shown below:
A. Normal Conditions of Operation (APU NONESSENTIAL)
(Ref. Fig. 008)
(1)
Ground Operation.
The APU will:
-
supply bleed air for the Main Engines Start (MES) on the ground in an altitude range between -610 m (-2000 ft.) and +2800 m (9200 ft.) at -54 DEG C to +55 DEG C (-65 DEG F to +131 DEG F),
-
supply bleed air for the air conditioning of the cabin and the cockpit,
-
supply shaft power to a 90 kVA generator.
(2)
Flight Operation.
The APU will:
-
supply bleed air in flight up to an altitude of 6096 m (20000 ft.),
-
supply shaft power to a 90 kVA generator.
If an increase in demand to the aircraft systems is necessary, the
supply of the electrical power has priority over the supply of bleed
air.
(3)
An electric DC motor starts the APU:
-in ground operation conditions, the APU is started by the aircraft batteries or Transfomer Rectifier Unit (TRU) or a combination of both,
-a start in flight is possible up to an altitude of 12500 m (41000 ft.) with the use of TRUs. A start in flight is possible up to an altitude of 7620m (25000 ft.) with the use of the aircraft batteries only.
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 flight after APU operation in icing conditions on the ground and during climb.
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. 31-32-00). The components that control and monitor the system are divided into two interfaces:
-Flight Crew Interface,
-Maintenance Interface.
Auxiliary Power System - Power Supply
Figure 007 (SHEET 1)
CES
Auxiliary Power System - Power Supply
Figure 007 (SHEET 2)
CES
Auxiliary Power System - Operating Envelope
Figure 008 (SHEET 1)
CES
Auxiliary Power System - Operating Envelope
Figure 008 (SHEET 2)
CES
(1)
Flight Crew Interface (Ref. Fig. 003) 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:
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