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25-57-00
ALL ú ú 07A Page 539 ú Oct 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
POWER DRIVE UNIT - MAINTENANCE PRACTICES
________________________________________
1. General_______
A. The following instructions are provided in this subject:
(1)
Manually Adjustable PDU Setting
(2)
Deactivate Retractable /Steerable PDU Limit Switches
B. Failure of a retractable/steerable PDU to retract, steer or drive may prevent the desired cargo movement. A retractable/steerable PDU may become inoperative for the following reasons:
(1)
Loss of electrical power to steering actuator.
(2)
Electrical/mechanical failure of steering actuator.
(3)
Steering actuator pinion gear runs off end of segment gear due to improper operation or failure of PDU limit switch, or failure of the steering actuator magnetically operated brake assembly.
(4)
PDU mechanical failure causing jamming or loss of function of steering/retract system.
(5)
Loss of electrical power to drive wheel actuator.
(6)
Electrical/mechanical failure of drive wheel actuator.
TASK 25-57-01-252-047
2. Manually Adjustable PDU Setting_______________________________
A. Access
(1) Location
(a) 210 Main Deck
B. Procedure
S 432-049
(1)
Grab both PDU handles and squeeze triggers to release lockpins from support fittings.
S 412-050
(2)
Rotate PDU clockwise or counterclockwise to the desired PDU angualar setting for size of cargo unit to be handled.
S 412-051
(3)
Release triggers to lock PDU on place. Red flags on triggers will disapear to indicate that the PDU is properly locked.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
25-57-01
ALL ú ú 10A Page 201 ú Oct 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
TASK 25-57-01-702-005
3. Retractable/Steerable PDU Manual Retraction
___________________________________________
A. Access
(1) Location Zones
210 Main Deck
B. Procedure
S 982-007
(1) Do the steps that follow to manually retract the PDU from aft lower cargo compartment (Fig. 202).
(a)
Remove the ceiling lining as required beneath the PDU to be retracted.
(b)
Open drain pan door beneath PDU in aft lower cargo compartment ceiling.
S 862-036
(2) Open these PDU circuit breakers as applicable, and attach DO-NOT-CLOSE tags:
(a)
On P129 panel, PDU No. 17R and 18R.
(b)
On P130 panel, PDU No. 19R1 and 19R2.
(c)
On P134 panel, PDU No. 17L and 18L.
(d)
On P135 panel, PDU No. 19L1 and 19L2.
S 022-010
WARNING: FAILURE TO DISCONNECT ELECTRICAL CONNECTOR MAY CAUSE INJURY TO
_______ PERSONNEL OR DAMAGE EQUIPMENT, IF POWER IS APPLIED DURING MANUAL RETRACTION OPERATION.
(3)
Disconnect steering actuator electrical connector.
S 022-011
(4)
Use a 3/8 inch drive ratchet extention to manually retract PDU.
S 822-012
(5)
Insert ratchet extention onto drive socket on the underside of the rotary steering actuator.
(6)
Turn counterclockwise until PDU is fully retracted.
S 022-013
(7)
Connect the steering actuator electrical connector to airplane electrical connector.
S 862-038
(8)
Remove the DO-NOT-CLOSE tags and close the applicable circuit breakers:
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