(i)  
Operate the pump for 30 seconds to move fuel inside the pump to the priming impeller.

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 28-31-01
 ALL  ú ú 03 Page 437 ú Oct 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 (j)  When the low pressure light on the pump control switch goes off, the pump is primed.
 NOTE: Do not operate the pump for more than five minutes
____ during the reprime operation.
 (k)  
Listen at the pump to make sure the override/jettison pump operates (or vibrates).

 (l)  
Put the applicable pump control switches to the off position: 1) CTR L 2) CTR R 3) OVRD 2 FWD 4) OVRD 2 AFT 5) OVRD 3 FWD 6) OVRD 3 AFT

 (m)  
If the PRESS indication light remains on, do this procedure: Low Pressure Light On the Pump Control Switch Remains On.

 NOTE: A low pressure indication for the override/jettison pump
____ can show that the pump has trapped air (the pump did not reprime).
 (n)  
At the refuel control panel, P42, put the CENTER refuel valve switch to the CLOSED position.

 (o)  
Do these steps to close the jettison transfer valves for the center wing tank: 1) Go into the wheel well for the wing landing gear. 2) Manually close the jettison transfer valves.

 (p)  
Close these circuit breakers and remove DO-NOT-CLOSE tags:

 1)  P6 Main Power Distribution Panel: a) 6E17 CTR & MAIN 2 JTSN VLV b) 6F17 CTR & MAIN 3 JTSN VLV
 G.  Low Pressure Light On the Pump Control Switch Remains On
 S 864-166
 (1)  
Do these steps to isolate an override/jettison low pressure
 indication condition:

 (a)  
With the applicable pump control switch for the override/ jettison pump in the ON position, go out to the pump and listen for pump operation.

 (b)  
If the pump operates, transfer fuel from one tank to another tank (AMM 28-26-00/201).

 (c)  
If there is fuel transfer, (and the low pressure indication continues), replace the pressure switch on the applicable override/jettison pump (AMM 28-42-01/401).

 (d)  
If the problem continues do these steps: 1) Remove the pressure switch (3) from the motor/impeller

 unit (4). 2) Use a syringe to add fuel to the pressure switch port.
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 28-31-01
 ALL  ú ú 01 Page 438 ú Oct 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 3)  Add a minimum of 10 fluid oz. (300 ml) of fuel or until the
 port is full. 4) Install the pressure switch (3). 5) Torque the pressure switch to 95 - 105 inch-pounds
 (10.7 - 11.8 Nm).
 6)  Measure the bonding resistance between the pressure switch body and the rear spar structure (SWPM 20-20-00).
 NOTE: The bonding resistance must not be more than
____ 0.050 ohm.
 7) Install the lockwire on the pressure switch (3). 8) Put the pump control switch for the applicable override jettison pump to the ON position. 9) Make sure the PRESS indication light, on the pump control switch goes off. 10) Listen at the pump to make sure the override/jettison pump operates (or vibrates). 11) Set the pump control switch to the off position.
 (e)  If the problem continues, (the pump does not reprime), then do these steps: 1) Increase the fuel load to the LEVEL 1 fuel quantity
 (Fig. 404, 405).
 2) Do this procedure again.

 H.  Put the Airplane Back to Its Usual Condition
 S 864-084
 (1)  Make sure all the pump control switches for the override/jettison pumps are in the off position.
 S 094-090
 WARNING: DO THE PROCEDURE IN AMM 32-00-30/201 TO REMOVE THE DOOR LOCKS.
_______ THE DOORS OPEN AND CLOSE QUICKLY AND CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 (2)  
　
中國(guó)航空網(wǎng) www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：747-400 AMM 飛機(jī)維護(hù)手冊(cè) 燃油 FUEL 4(39)