(4)
Install the spring adapters (1) with the washers (2) and the nuts (3).
(5)
Close the APU access door 316AR.
(6)
Adjust the drain tank/spring adapter assembly as follows:
(a)
Move the center of the spring adapters (1) into the center of the APU drain lines.
(b)
Adjust the preload of the spring adapters (1) until the dimension C is 48.0 mm (1.8897 in.).
(7)
Fully tighten the screws (6) and the nuts (10).
(8)
Connect and tighten the nuts (4) to the drain lines. Subtask 49-17-41-865-055
C.
Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s): 1KD, 2KD.
Subtask 49-17-41-790-050
D. Test
(1)
Start and operate the APU (Ref. TASK 49-00-00-860-005).
(2)
Do the APU shutdown (Ref. TASK 49-00-00-860-006).
(a) After the shutdown, examine the joints of the drain tank for leaks.
NOTE : Leaks are not permitted.
____
________
5. Close-up
Subtask 49-17-41-410-052
A. Close Access
(1)
Make sure that the work area is clean and clear of tool(s) and other items.
(2)
Close the APU access doors 315AL, 316AR (Ref. TASK 52-41-00-410-001).
(3)
Remove the access platform(s).
ENGINE - DESCRIPTION AND OPERATION
__________________________________
R **ON A/C 001-003, 051-099, 401-499,
1. General
_______
The APU supplies:
-
pneumatic power for 'Main Engine Start (MES)',
-
pneumatic power for the environmental control system (ECS),
-mechanical shaft power to drive an AC generator and a fan. The fan, an integral part of the APU, cools its lubrication system and the APU compartment.
2. System Description
__________________
(Ref. Fig. 001)
The APU consists of three basic modules:
A. Power Section (Ref. 49-21-00)
The power section supplies shaft power to drive:
-
the load compressor,
-
the gearbox with accessories (incl. AC generator). It is essentially a single-shaft assembly with the following major components:
-single-stage, titanium alloy centrifugal compressor with a 6:1 pressure ratio,
-reverse-flow annular combustion chamber,
-single-stage radial-inflow turbine.
B. Load Compressor (Ref. 49-23-00) The load compressor is a direct-drive modular assembly, installed between the power section and the accessory gearbox. It is a single-stage centrifugal compressor. Inlet guide vanes (IGVs) are installed at the entrance of the compressor housing to control the compressor output to the aircraft pneumatic system.
C. Accessory Gearbox (Ref. 49-26-00) The accessory gearbox is installed on the end face of the load compressor casing and is driven by the power section. It has drive pads for:
-an AC generator,
-
a starter motor,
-
a generator scavenge oil pump,
-
a fuel control and lube pump,
-
a cooling fan.
Auxiliary Power Unit Figure 001
R EFF : 001-003, 051-099, 401-499, Page 249-20-00 Config-1 Aug 01/05
CES
3. Operation/Control and Operation
_______________________________
The following components control APU start:
-master switch 14KD (MASTER SW) and
-
APU start switch 2KA (APU START)
A.
APU Start
(1)
When the MASTER SW 14KD is set to ON, the ECB is energized.
(2)
This causes the ECB to transmit the following commands:
- open the APU air-intake flap;
- open the FUEL LP VALVE 3QF;
-energize the APU fuel-feed pump 4QC.
(3)
Subsequent to setting the APU START switch to the 'ON'-position:
-a signal is transmitted to the ECB. This signal is used to start the APU,
-the starter motor 8KA does not engage unless the air intake flap is open. This is indicated to the ECB via the open position switch of the air intake door-actuator.
-at approximately 7% rpm, the ECB energizes the igniter and opens the fuel solenoid valve on the Fuel Control Unit (FCU). It gives the correct metered fuel flow for engine light up. Fuel flows from the FCU to the Flow Divider and Drain Valve Assembly (FDDVA) which controls the engine rpm during acceleration. The starter motor 8KA helps the engine to accelerate to 50% rpm. The Exhaust Gas Temperature (EGT) increases at a related constant temperature as the engine accelerates.
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