(2)  
Retriever, claw type

(3)  
Pressure Washer (Commercially Available) - Low pressure water or steam - to supply the solvent to the screen.

(4)  
Container - Oil and Solvent resistant

(5)  
Gloves - Oil and Solvent resistant

(6) 
 Goggles, Safety

B.  Consumable Materials
(1)  B00722 Solvent -P-D-680
C.  References
(1)  
AMM 49-11-0/401, APU Power Plant

(2)  
AMM 49-11-0/501, APU Power Plant

D.  Procedure
(1)  Make sure that the switch and the circuit breaker are set correctly:
(a)  
Make sure the APU MASTER SWITCH is in the OFF position with a DO-NOT-OPERATE tag attached.

(b)  
Make sure this circuit breaker is open with a DO-NOT-CLOSE tag attached: 1) E3-3 Electrical Shelf, M280 module -APU Accessory Unit

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G42408
Horizontal Stabilizer Trim Lock Installation  500 
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(2)  
Make sure the electrical connectors are disconnected:

(a)  
Make sure the electrical connector is disconnected from the stabilizer trim electric actuator.

(b)  
Make sure the electrical connector is disconnected from the autopilot stabilizer trim servo.

(3)  
Clean the fan inlet screen:

(a)  
Clean the fan inlet screen with the vacuum cleaner. 1) Put the nozzle of the vacuum cleaner in the inspection tube to remove all blockage.

2)  If there are pieces too large or heavy for the vacuum cleaner, use a claw type retriever to remove them.

(b)
With a flashlight, examine the fan inlet screen for any remaining blockage.

1)  If you have found any blockage, do these steps to clean the fan inlet screen with
solvent:
a) Remove the fire loop bracket from crossover duct.
b) Remove the two clamps from the crossover duct.
c) Remove the crossover duct and the two gaskets.
d)  Put a cover on the cooling air inlet to the generator and the cooling air inlet
to the oil cooler.
e) Put a container under the cooling fan housing.
f)  Place the solvent into the pressure washer.
g) Place the nozzle of the washer into the inspection tube.
h)  Wash the screen with the solvent.
i)  Use the container to catch the solvent and dissolved blockage.
j)  Rinse the inspection tube, the cooling fan and the APU with clean water.
k)  Remove the cover from the cooling air inlet to the oil cooler.
l)  Do the inspection of the oil cooler (Para. 4).
m)  Remove the cover from the cooling air inlet to the generator.
n)  Put the two gaskets in the crossover duct.
o)  Put the crossover duct on the cooling fan and the oil cooler.
p)  Reinstall the two clamps on the crossover dust.
q)  Reinstall the fire loop bracket on the crossover duct.
2)  With a flashlight, examine the fan inlet screen for any remaining blockage. a) If any blockage is found, remove the APU and clean or replace the fan inlet screen (AMM 49-11-0/401).
4.  Inspect the oil cooler
A.  Remove the cooling air crossover duct.
(1)  
Disconnect all components from cooling air crossover duct.

(2)  
Remove the upper and lower clamps from the cooling air crossover duct.

(3)  
Remove the cooling air crossover duct.

B.  Examine the oil cooler for blockage.
(1)
If the oil cooler inlet or outlet surfaces have blockages, remove the blockages.

(2)  
If the air flow tubes have any blockages, remove the blockages.

C.  Install the cooling air crossover duct.
(1)  
Install the upper and lower clamps.

(2)  
Install all components to cooling air crossover duct.

5.  Restore Airplane to Normal Configuration
A.  Close access door to compartment aft of pressure bulkhead.
B.  Close circuit breaker on M280 module -APU accessory unit on E3-3 electrical shelf.
C.  Remove "IN WORK" placard from BATTERY SWITCH.
May 01/03 49-51-0 Page 203 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.

APU Cooling Fan - Removal/Installation
1.  General
　
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