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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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747-400 MAINTENANCE MANUAL
(b) Install the APU hydraulic jackstand (optional to the three fishpole hoists) (Fig. 402): 1) Put the hydraulic jackstand on the platform of the scissors
lift. 2) Use a forklift to put the APU and APU stand assembly on the hydraulic jackstand. 3) Attach the cradle to the hydraulic jackstand with the four bolts and four nuts.
4) Turn the four handles of the crank-down stabilizers clockwise until the four crank-down stabilizers touch the platform.
S 214-035
(2) Visually examine the APU mount assemblies for cracks, wear and damage (Fig. 403).
NOTE: The APU mount brackets, cone bolt support block and aft mount
____ link can be damaged on the APU when the APU is moved.
S 484-110
(3) Make sure the three thread protectors are installed on the three cone bolts (3).
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CAUTION: REMOVE THE PROTECTION COVERS FROM THE OPENINGS AS NECESSARY.
_______ IF YOU DO NOT REMOVE THE PROTECTION COVERS, DAMAGE TO THE APU CAN OCCUR.
CAUTION: CAREFULLY LIFT THE APU IN POSITION TO PREVENT DAMAGE TO THE
_______ CONICAL SURFACES OF THE CONE BOLTS.
CAUTION: DO NOT HOLD THE EGT THERMOCOUPLE HARNESS WHILE YOU LIFT THE
_______ APU. THE HARNESS AND THE PROBES FOR THE EGT THERMOCOUPLE CAN BE EASILY DAMAGED IF THEY ARE UNUSUALLY STRESSED.
(4)
Slowly and carefully lift the APU into position.
S 424-109
(5)
Connect the APU to the APU mounts in the airplane (Fig. 403):
(a)
Remove the three thread protectors from the three cone bolts (3).
(b)
Install the three washers (4), (7) and three cone bolt nuts (5), (8) on the three cone bolts (3).
NOTE: Use only new or dye penetrant examined cone bolt nuts
____
(5), (8).
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49-11-01
ALL ú ú 05 Page 423 ú Jun 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
(c) Do the torque limit test for the three cone bolt nuts (5), (8):
1) Tighten the three cone bolt nuts to a run-on torque of not more than 150 pound-inches (17.0 newton-meters) until you can see one to two full threads and the cone bolt chamfer extends below each nut.
NOTE: Use an open-end wrench on the flats of the cone bolt
____ to hold the cone bolt in position while you tighten each nut. You can find the flats of the cone bolt between the shockmount and the APU mount bracket or cone bolt support block.
2) Make sure the three washers (4), (7) do not touch the bottom surface of the two APU mount brackets and cone bolt support block (9).
3) Make sure the break-away torque necessary to turn the three nuts from this position is more than 18 pound-inches (2.0 newton-meters).
4) Replace the nut(s) that do not meet these torque limits. 5) If the nut(s) were replaced, do the torque limit test again for the new nut(s).
(d)
Tighten the three cone bolt nuts (5), (8) to 800-900 pound-inches (90.4-101.7 newton-meters).
G.
APU Ground Equipment Removal
S 084-111
(1)
Remove the APU ground equipment (three fishpole hoists or APU hydraulic jackstand):
(a)
Remove the three fishpole hoists (Fig. 401):
1) Disconnect the left and right front yokes of the APU stand assembly from the two mount brackets on the front of the APU.
2) Disconnect the APU stand assembly from the two ground
handling lugs on the sides of the APU. 3) Lower the cradle to the ground with the fishpole hoists. 4) Disconnect and remove the three fishpole hoists from the
APU compartment.
(b) Remove the APU hydraulic jackstand:
1) Disconnect the left and right front yokes of the APU stand assembly from the two mount brackets on the front of the APU (Fig. 401).
2) Disconnect the APU stand assembly from the two ground handling lugs on the sides of the APU. 3) Use the APU hydraulic jackstand to lower the cradle from the APU compartment (Fig. 402).
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