(4)
Open fueling station access door (Fig. 201) and remove fueling nozzle receptacle cap.
(5)
Connect defueling hose nozzle grounding jacks to grounding receptacle on wing.
(6)
Connect defueling hose nozzle to fueling nozzle receptacle. Open nozzle fuel flow shutoff handle.
CAUTION: BEFORE DEFUEL OPERATIONS, MAKE SURE THE HOSE NOZZLE AND HOSE-END CONTROL VALVE (IF USED) ARE CONFIGURED PER THE SUPPLIER'S MAINTENANCE MANUAL. FAILURE TO DO SO COULD CAUSE DAMAGE TO THE AIRPLANE.
NOTE: Defueling nozzle should be equipped with a filter screen.
(7)
Check that the fueling valve switches on fueling control panel P15 are in CLOSED position. VALVE POSITION LIGHTS should be extinguished.
(8)
Record fuel quantity for tank(s) to be defueled. Momentarily hold test switch on P15 panel on TEST GAGES & FUELING PRECHECK position on airplanes with VTO, or on TEST GAGES position on non-VTO airplanes. Indicator should move downscale. Release switch and indicator should return to its original position + 50 pounds or + 25 kilograms.
(9)
Open defueling valve access door (Fig. 202) and place defueling valve to OPEN position.
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5C8 Fueling Station Component Location
Aug 01/96 Figure 201 28-23-0
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(10)
Make sure the engine No. 2 fuel shutoff valve is open. The shutoff valve is normally closed on the ground; opened to do the defueling procedure. (valve blue position light on forward overhead P5 panel off). If not:
(a)
Open the engine ignition circuit breakers on P6 panel.
(b)
Make sure the fire switches are pushed in.
(c)
Put the engine No. 2 start lever on aisle stand in IDLE position.
(11)
Position crossfeed valve control on P5 panel to open crossfeed valve. Make sure the valve position light is dim (blue).
NOTE: If defueling tank number two (right side) crossfeed valve may be open or closed.
(12)
Put the fuel boost pump switches, found on the forward overhead panel, as shown in table below for applicable tank.
FUEL PUMP SWITCH SWITCH POSITION FOR DEFUELING
TANK NO. 1 TANK NO. 2 CENTER TANK
AFT 1 Fuel Pump Switch FWD 1 Fuel Pump Switch AFT 2 Fuel Pump Switch FWD 2 Fuel Pump Switch L CTR Fuel Pump Switch R CTR Fuel Pump Switch ON ON OFF OFF OFF OFF OFF OFF ON ON OFF OFF OFF OFF OFF OFF ON ON
(a) To operate any of the fuel boost pumps, you must be in the flight compartment to continuously monitor the fuel quantity and the low pressure indication in the fuel tank.
WARNING: DO NOT OPERATE ANY FUEL BOOST PUMP IF THE LOW PRESSURE LIGHT COMES ON AND STAYS ON. FUEL VAPORS IN THE TANK MAY IGNITE AND CAUSE A FIRE OR EXPLOSION.
1) Immediately put the applicable fuel boost pump switch(es) to OFF if the LOW PRESSURE light comes on and stays on.
NOTE: When defueling or transferring fuel with minimum backpressure to the pumps, it is possible for the low pressure light(s) to be on. In this case, monitor the tank quantity and put the pump switch(es) to OFF if the tank quantity is not changing.
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(13)
Start the fuel truck defueling pump.
(14)
Continue defueling until fuel quantity indicator shows desired quantity of fuel remaining in tank, or until corresponding fuel. low pressure warning light comes on, then put the applicable boost pump switches to OFF.
(15)
Put the crossfeed valve on P5 panel to CLOSE. Make sure the position light shows bright while valve is in transit and goes off when the valve is closed.
(16)
If engine No. 2 start lever was put in IDLE position, return the start lever to CUTOFF and close the engine ignition circuit breaker on P6 panel.
(17)
Stop the fuel truck defueling pump.
(18)
Close the defueling valve, and close the defueling valve access door.
(19)
Close the nozzle fuel flow shutoff handle. Disconnect the defueling hose nozzle and disconnect the nozzle grounding jack.
(20)
Install the fueling receptacle cap and close the fueling station access door.
(21)
Remove electrical power if it is not necessary.
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504 Location of Defueling Valve and Fuel Sump Drain Valves 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737 AMM 飞机维护手册 燃油 FUEL(149)
