52-31-00
 ALL  ú ú 02 Page 607 ú Feb 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 B. References
 (1)  
AMM 52-31-00/201, Nose Cargo Door

 C.
Access

 (1)  
Location Zone
 801 Nose Cargo Door

 D.
Procedure

 S 866-021
 (1)  
Open the nose cargo door (AMM 52-31-00/201).

 S 216-022

 (2)  
Examine the components of the door mechanism.

 (a)  
Examine the hinges. 1) Look for debris. 2) Look for corrosion. 3) Look for damage. 4) Look for loose or missing fasteners.

 (b)  
Examine the lift drive unit. 1) Look for loose or missing fasteners. 2) Look for corrosion. 3) Look for chafed or damaged wires. 4) Make sure the drive unit is securely mounted to the

 structure.

 (c)  
Examine the flexible drive shafts. 1) Look for debris in the drive shafts. 2) Look for loose or missing fasteners. 3) Look for damage or corrosion on the drive shafts.

 (d)  
Examine the lift linear actuators.
 1) Look for debris.
 2) Look for damage.
 3) Look for corrosion.

 (e)  
Examine the latch actuators. 1) Look for damage. 2) Look for debris. 3) Look for chafed or damaged wires. 4) Make sure the actuators are securely attached to the

 structure.

 (f)  
Examine the push-pull cams and actuators. 1) Look for debris. 2) Look for corrosion. 3) Make sure the cams and actuators are securely attached to

 the structure.
 S 866-023
 (3)  Close the nose cargo door (AMM 52-31-00/201).
 TASK 52-31-00-716-027
 3. Operational check of the Nose Cargo Door Manual Drive
_____________________________________________________
 A. General
 (1)  This is a scheduled maintenance task.
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 52-31-00
 ALL  ú ú 02 Page 608 ú Jun 10/94
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 B. References
 (1)  
AMM 52-31-00/201, Nose Cargo Door

 C.
Access

 (1)  
Location Zone
 801 Nose Cargo Door

 D.
Procedure

 S 716-024
 (1)  Do a check of the manual operation of the latch actuators.
 CAUTION: DO NOT CRANK THE LATCH ACTUATOR WITH MORE THAN
_______ 8 POUND-FEET TORQUE. THIS CAN CAUSE DAMAGE TO THE MANUAL DRIVE INPUT.
 (a)  Manually drive each of 16 latch actuators to fully unlatch the pins (approximately 150 turns from the fully latch to unlatched position) and make sure the torque is not more than 20 pound-inches.
 S 716-025
 (2)
Do a check of the manual operation of the push-pull cam actuators.

 (a)  
Manually drive the push-pull cam actuator to move the cam to the fully open position.

 NOTE: Approximately 200 turns to fully open the cam from the
____
 fully closed position.

 S 716-026
 (3)  Do a check of the manual operation of the linear actuators.
 CAUTION: MAKE SURE TO DRIVE THE TWO LINEAR ACTUATORS
_______ SIMULTANEOUSLY. THE UNEQUAL LOAD DISTRIBUTION CAN CAUSE DAMAGE TO THE LINEAR ACTUATORS.
 (a)  Simultaneously drive the two linear actuators with the alternate drive extension or the speed wrench in the open direction (counterclockwise) until the door starts to open.
 NOTE: It is not necessary to completely open the door for this
____ check. Also, the same air pressure supply and the hose diameter must be used on the alternate drive extension or the speed wrench to make sure the rotational speed (RPM) is the same.
 S 866-028
 (4)  Electrically close and latch the nose cargo door (AMM 52-31-00/201).
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 52-31-00
 ALL  ú ú 02 Page 609 ú Jun 10/94
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
　
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