S 216-010
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747-400
MAINTENANCE MANUAL

 S 716-012
 (11) Do an operational check for the latch, push-pull cam and lift mechanisms.
 NOTE: The purpose of this check is to make sure that the latch,
____ push-pull cam and lift mechanisms operate in sequence. The limit switches stop the operation of one mechanism and start the operation of the next mechanism. Therefore, if a mechanism does not operate completely, it can cause the next mechanism to stop.
 (a)  
Electrically open the nose cargo door a minimum of 24 inches at the bottom.

 (b)  
Make sure the latch, push-pull cam and lift mechanisms operate in sequence.

 S 716-013
 (12)
 Do an operational check for the latch actuators.

 (a)  
Electrically close and latch the nose cargo door.

 NOTE: When the door opens or closes it can make unusual noise
____ when the latch pins engage the spherical bearings.
 (b)  
Listen for unusual sounds and other evidence of high operating loads at the latch actuators as latches close.

 (c)  
If you think the latch actuators have high operating loads, do these steps:

 CAUTION: DO NOT CRANK THE LATCH ACTUATOR MORE THAN 8 POUND-FEET.
_______
 THIS CAN CAUSE DAMAGE TO THE MANUAL DRIVE INPUT.

 (d)  
Measure the torque necessary to manually crank each of the 16 latch actuators in the retract direction.

 (e)  
If the manual cranking torque is more than 20 pound-inches, adjust the portal latch fitting.

 NOTE: If a large number of portal latch fittings need
____ adjustment, or if you do not know which portal latch fittings need adjustment, do an adjustment check for all portal latch fittings (AMM 52-31-00/501).
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 S 866-014
 (13) With all the latch pins retracted, electrically close and latch the nose cargo door.
 NOTE: When the door opens or closes it can make unusual noise when
____ the latch pins engage the spherical bearings.
 (a)  Hold the switches in the closed position approximately 5 seconds after all electrical operation stopped.
 S 216-015
 (14) Make sure the LATCHES CLOSED light on the control panel and all green lights on annunciator module come on.
 NOTE: The LATCHES CLOSED light will not come on until all the latch
____ pins are fully extended. The green lights on the annunciator module come on individually as each latch pin is fully extended.
 S 826-016
 (15)
 If the LATCHES CLOSED light does not come on and the amber NOT LCHD light is on, manually crank that latch actuator to the closed (extended) stop position.

 S 826-017

 (16)
 If the LATCHES CLOSED light comes on and the amber NOT LCHD light goes off, adjust the latch fitting (AMM 52-31-06/401) or the replace the latch actuator (AMM 52-31-05/401).

 S 966-018

 (17)
 If the LATCHES CLOSED light comes on and one or more of the amber NOT LCHD lights remain on, replace the applicable indication position switch (AMM 52-71-01/401) after a visual check that all the latch pins are in the fully extended positions.

 S 816-019

 (18)
 If the LATCHES CLOSED light remains off when all 16 green LATCHED lights come on, do a system test for the nose cargo door (AMM 52-31-00/501).

 TASK 52-31-00-216-020
 2. Inspection of the Nose Cargo Door Operating Mechanism
_____________________________________________________
 A. General
 (1)  This is a scheduled maintenance task.
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