S 865-217
(4)
In the flight compartment, do these steps:
(a)
Make sure the engine start switches are in the OFF position.
(b)
Make sure all six of the the FUEL PUMP switches are in the OFF position.
NOTE: All six fuel pump switches must be set to the OFF
____ position. If all six switches are not at the OFF position, pressurized fuel may come out when you remove the plug from the fuel filter housing. If the center fuel boost pump is on during the test, you will get incorrect pressure indications.
(c)
Make sure the APU master switch is OFF.
(d)
Make sure the engine start levers are in the CUTOFF position.
S 845-257
(5) METHOD 1 - Measure the outlet pressure at the drain for the fuel filter housing:
(a)
Open the left fan cowl at one of the engines
(AMM 71-11-02/201).
(b)
Put a 5-gallon container below the drain plug for the engine fuel filter housing.
(c)
Remove the drain plug from the fuel filter housing (Fig. 502A) (AMM 73-11-02/401).
NOTE:____Fuel will drain from the opening. Make sure the pressure gage hose fitting is prepared for installation to keep fuel leakage to a minimum.
1) Discard the O-ring.
(d) Attach the pressure gage hose fitting (Fig. 502B) at the fuel filter housing.
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737-300/400/500MAINTENANCE MANUAL
(e)
Open the airplane fuel crossfeed valve.
(f)
Move to the engine start lever to the RUN position for the engine that has the pressure gage attached.
(g)
Go to the steps: "Do the Test of the Fuel Boost Pumps".
S 845-256
(6) METHOD 2 - Measure the outlet pressure at the forward spar fitting for the fuel feed low pressure switch:
(a)
Close the removal valve for the applicable fuel boost pump (AMM 28-42-11/401).
(b)
Remove the fuel feed low pressure switch (AMM 28-42-11/401).
NOTE: Remove only one low pressure switch at a time to prevent
____ a fuel spill if the wrong boost pump is operated. Make sure the removal valve for the fuel boost pump is closed to keep fuel leakage to a minimum.
(c)
Attach the pressure gage hose fitting at the forward spar fitting.
(d)
Open the removal valve for the fuel boost pump.
G. Do the Test of the Fuel Boost Pumps
S 785-225
(1) Do the steps that follow for each of the fuel boost pumps in the No. 1 tank and the No. 2 tank (No. 1 AFT, No. 1 FWD, No. 2 AFT, No. 2 FWD):
(a) Make sure only one boost pump is turned on each time you do these steps.
NOTE: Do not try to test more than one boost pump at a time.
____
(b)
Open the bleed valve on the pressure gage hose until fuel comes out of the drain hose and the pressure becomes stable.
(c)
Close the bleed valve.
(d)
Record the pressure shown on the pressure gage as the "Pump OFF" pressure.
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737-300/400/500MAINTENANCE MANUAL
(e)
Push the boost pump switch to the ON position and wait one minute for the pump to warm up.
(f)
Open the bleed valve on the pressure gage hose and drain fuel for approximately 10 seconds.
(g)
Close the bleed valve.
(h)
After approximately 20 seconds, examine the gage to see if the pressure has become stable.
(i)
Record the pressure shown on the pressure gage as the "Pump ON" pressure.
(j)
Push the boost pump switch to the OFF position.
(k) 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737-300 400 500 AMM 飞机维护手册 燃油 FUEL 2(84)
