28-31-01
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A
747-400 MAINTENANCE MANUAL
(f) 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).
S 654-064
(3) METHOD 2 - Use the pressure refuel system to operate the wetting
________
system:
(a) At the refuel control panel, P42, put the CENTER refuel valve switch (valve position control switch) to the OPEN position.
NOTE: Do not open any other refuel valves.
____
(b)
Start the pressure refuel operation (AMM 12-11-01/301).
(c)
Use a minimum of 35 PSI nozzle pressure during the refuel
_______
operation.
(d)
Wait until the fuel quantity in the center wing tank is above approximately 12,000 lbs (5500 kgs).
NOTE: At different pitch and roll attitudes the fuel quantity
____ that is necessary for the wetting system to operate will change. See the LEVEL 2 pump priming graphs to find the necessary fuel quantity (Fig. 405).
(e)
Put the applicable pump control switch for the
override/jettison pump to the ON position:
1) CTR L
2) CTR R
(f)
Operate the pump for 30 seconds to move fuel inside the pump to the priming impeller.
(g)
When the PRESS indication 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.
(h)
Listen at the pump to make sure the override/jettison pump operates (or vibrates).
(i)
Put the applicable pump control switch to the off position: 1) CTR L 2) CTR R
(j)
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).
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28-31-01
ALL ú ú 03 Page 436 ú Oct 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
(k) At the refuel control panel, P42, put the CENTER refuel valve switch to the CLOSED position.
S 654-081
(4) METHOD 3 - Transfer fuel from the inboard main tanks to operate the
________
wetting system:
(a)
Make sure there is enough fuel in the No. 2 and 3 mains tanks to operate the main tank override/jettison pumps (Fig. 404).
(b)
Make sure the ground locks for the landing gear are installed.
WARNING: YOU MUST CAREFULLY DO THE STEPS IN THE TASK BELOW TO
_______ INSTALL THE DOOR LOCKS ON THE LANDING GEAR DOORS. THE DOORS CAN CLOSE QUICKLY IF YOU DO NOT INSTALL THE DOOR LOCKS CORRECTLY. THIS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
(c)
Do this task: "Installation of the Door Locks on the Wing Landing Gear" (AMM 32-00-30/201).
(d)
Do these steps to open the two jettison transfer valves in the center wing tank. 1) Open these circuit breakers and attach DO-NOT-CLOSE tags: 2) P6 Main Power Distribution Panel:
a) 6E17 CTR & MAIN 2 JTSN VLV
b) 6F17 CTR & MAIN 3 JTSN VLV 3) Go into the wheel well for the wing landing gear. 4) Manually put these jettison transfer valves to the OPEN
position (AMM 28-31-04/401): a) Left CWT jettison transfer valve b) Right CWT jettison transfer valve.
(e)
At the refuel control panel, P42, put the CENTER refuel valve switch to the OPEN position.
(f)
Put these pump control switches for the override/jettison pumps for the inboard main tanks to the ON position: 1) OVRD 2 FWD 2) OVRD 2 AFT 3) OVRD 3 FWD 4) OVRD 3 AFT
(g)
Wait until the fuel quantity in the center wing tank is above approximately 12,000 lbs (5500 kgs).
NOTE: At different pitch and roll attitudes the fuel
____ quantity that is necessary for the wetting system to operate will change. See the LEVEL 2 pump priming graphs to find the necessary fuel quantity (Fig. 405).
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