S 862-035

 (11)
 Adjust the clearance of the up sensors as shown (Fig. 201).

 (a)  
Use the different lengths of spacers to supply the correct clearance.

 S 862-058
 (12)
 Remove the DO-NOT-OPERATE tag from these switches on the P5 panel:

 (a)  
HYD PUMP DEMAND 1

 (b)  
HYD PUMP ENGINE 1

 S 862-036
 (13)
 Supply power to the No. 1 hydraulic system (AMM 29-11-00/201).

 S 862-037

 (14)
 Remove the DO-NOT-OPERATE tag and move the control handle for the landing gear to the DN position.

 (a)  
Make sure the nose landing gear moves to the down position.

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747-400 MAINTENANCE MANUAL
 S 432-038
 (15)
 Connect the operator rods to the doors on the forward nose gear.

 (a)  
Make sure the left rod connects to the left door and the right rod connects to the right door.

 S 742-039
 (16)
 Do the ground test for the PSEU (AMM 32-09-03/501).

 S 862-040

 (17)
 Remove the DO-NOT-CLOSE tag and close this circuit breaker on the main power distribution panel, P6:

 (a)  
6C28, ALT LG EXT NOSE

 S 092-059
 WARNING:_______OBEY THE REMOVAL PROCEDURE FOR THE DOOR LOCKS. THE DOORS OPEN AND CLOSE QUICKLY. THE MOVEMENT OF THE DOOR CAN CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT.
 (18) Remove the door lock on the nose and the main landing gear if the sensor installation is completed (AMM 32-00-30/201).
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 NOSE GEAR LOCK SENSOR - MAINTENANCE PRACTICES
_____________________________________________
 1.  General_______
 A.  This procedure consists of these tasks:
 (1)  
The removal of the nose gear lock sensor.

 (2)  
The installation of the nose gear lock sensor.

 (3)  
The test of the nose gear lock sensor.

 (4)  
The adjustment of the nose gear lock sensor.

 (5)  
The adjustment of the nose landing gear sensor bracket.

 B.  
A correctly installed sensor will give the necessary clearance as shown in Fig. 201, thus clearance adjustment usually is not necessary.

 (1)  
Measure the clearance between the nose landing gear lock sensor and the target (Refer to the task to Adjust Nose Gear Lock Sensor) if the sensor support bracket is moved or the aluminum shear pin is damaged. When you replace a damaged pin, make sure the replaced pin has the same part number. The shear pin breaks when an emergency occurs. When the pin breaks, the nose gear will lock in the down position. Also, the shear pin prevents damage to switches, brackets and lock links that could occur if the clearance between the sensor and target were blocked.

 C.  
The lock sensors are found on the upper drag strut. The sensor target is attached to a bracket found on the upper end of the downlock link assembly. The primary sensor equipment number is S397 and the alternate sensor is S424. The sensor leads connect to two terminal strips, T400 the primary sensor leads and T701 the alternate sensor leads. These terminal strips are on the left and right sides of the ceiling light for the nose gear wheel well.

 TASK 32-61-03-002-053
 2.  Nose Gear Lock Sensor Removal (Fig. 201)_____________________________
 A.  Standard Tools and Equipment
 (1)  
Plastic scraper that is not abrasive or conductive

 B.  
References

 (1)  
AMM 09-11-00/201, Towing

 (2)  
AMM 32-00-30/201, Landing Gear Door Locks

 (3)  
AMM 32-09-02/201, Air/Ground Relay System