28-21-00
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A 737-300/400/500MAINTENANCE MANUAL
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28-21-00
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 737-300/400/500MAINTENANCE MANUAL
Pressure Fueling System Flow Diagram
Figure 3
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28-21-00
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
737-300/400/500MAINTENANCE MANUAL
PRESSURE FUELING SYSTEM - TROUBLE SHOOTING
__________________________________________
1. General_______
A. These trouble shooting procedures were developed from data from the pressure fueling system during a standard refueling operation. The procedures are in a tree-type configuration. The steps related to the refuel operation (heavy-line boxes) are connected by arrows to show the path through the tests that gives good (system operable) results (OK condition).
B. When a step in the refuel operation does not give a good result, follow the NOT OK line to the box that contains the applicable problem. Refer to the procedure shown in that box. Continue to analyze the results of each step in the refuel operation until you find the applicable solution to the problem. Do the steps necessary to correct the problem. Then do the step where you first found the problem again to make sure you corrected the problem.
C. All of the trouble shooting procedures for electrical components must be done with good wiring and electrical power available. If the procedure in the trouble shooting block does not correct the problem, do a check of the wiring continuity. Refer to the applicable diagram in the Wiring Diagram Manual (WDM).
D. Problems with the fueling shutoff valves can be caused by mechanical or electrical problems in the valve. Problems with the fueling shutoff valve can also be caused by problems with the DC float switch that closes the applicable fueling shutoff valve when each tank is full. If these conditions are applicable, the float switch is usually the cause of the problem:
(1)
The fueling shutoff valve does not close when the fuel level is at its standard full capacity.
(2)
The fueling shutoff valve closes when you set the switch for the fueling shutoff valve to the CLOSE position.
E. It is usually not necessary to do a calibration for the fuel shutoff because the fuel level for shutoff is set by the float switch. The float switch is installed on a mounting bracket that you cannot adjust. If the fueling shutoff valves always close at a level that is higher or lower than the standard full level, examine the mounting bracket for the float switch. Find out if the mounting bracket is bent, damaged, or installed incorrectly.
2. Prepare for Trouble Shooting____________________________
A. Procedure
(1)
To find the correct fuel quantities for fueling shutoff and to compare precisely with fuel quantities measured before, it is recommended that you set the airplane in the standard attitude (0° roll and 0.15° nose down).
(2)
Make sure the fuel tank(s) are empty when you do the trouble shooting procedure (Ref 28-23-00/201).
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本文链接地址：737-300 400 500 AMM 飞机维护手册 燃油 FUEL 2(33)
