(c) Connect Gas Turbine Engine Tester to Engine 1) Repeat steps 2.A.(3)(a) thru 2.A.(3)(h).
NOTE: Connecting of control air pressure hose assembly (3) and oil pressure hose assembly is not necessary for this test.
2) Disconnect the electrical plug (37) from the tachometer generator (36).
3) Connect the electrical cable or test cable assembly (46) to the tachometer generator (36) and the electrical plug (37).
(d) Test Bleed Air Valve Opening Rate 1) Perform prestart procedure per par. 2.A.(4). 2) Observe engine operating requirements given in par. 1.D while performing test. 3) APUs WITHOUT ALLIEDSIGNAL SB GTCP85-49-7096; if you must operate the
APU with the lower shroud removed, make sure all persons are not in the hazard area (AMM 49-11-0/201).
WARNING: DO NOT OPERATE THE APU WITH THE LOWER SHROUD REMOVED IF PERSONS ARE IN OR DIRECTLY BELOW THE APU COMPARTMENT. YOU MUST BE A MINIMUM OF 3 FEET AWAY FROM THE OUTER EDGE OF THE APU COMPARTMENT OPENING TO OPERATE THE APU WITH THE LOWER SHROUD REMOVED. AN APU TURBINE WHEEL SEPARATION DURING OPERATION CAN CAUSE INJURY TO PERSONS.
NOTE: APUs with AlliedSignal SB GTCP85-49-7096 have an external shield around the turbine plenum and have no hazard area.
4) On forward overhead panel, position APU master switch to START and release.
NOTE: If APU master switch is initially positioned to ON and air inlet door fully opens before APU master switch is moved to START, start and stop relay K1 will not be energized and engine will not start.
5) Allow engine to accelerate to governed speed.
6) With no load applied, engine speed should stabilize at 102% rpm (max) as
indicated on indicator (15) (Fig. 502).
7) On forward overhead panel, position APU BLEED valve switch to ON.
8) Position air conditioning R PACK and L PACK valve switches to ON. For
complete operation of air conditioning system, Ref Chapter 21, Air Conditioning.
Aug 01/95 49-21-01 Page 515
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9) Position tester load switch (29) to ON.
10) Measure time from actuation of tester load switch until fuel pressure gage (2) shows first peak reading. This should occur within 12 to 14 seconds, indicating that valve has reached full load position.
11) Observe engine speed drop on indicator (15) at load application. Speed drop should not exceed 2% engine rpm.
12) Move air conditioning control cabin temperature selector switches to MANUAL COLD until air mix valves indicate COLD.
13) Observe engine speed at full bleed load operation on indicator (15). Speed should stabilize at 100% to 98% engine rpm.
14) Observe engine exhaust gas temperature on indicator (7) at full bleed air load operation. This temperature is load control thermostat controlling temperature and should not exceed 650°C.
15) Position tester load switch to OFF.
16) Position air conditioning R PACK and L PACK valve switches to OFF.
17) Position APU BLEED valve switch to OFF.
18) Allow engine to operate at no load governed speed for 1 minute (minimum).
19) Position APU master switch to OFF.
20) If time limit in step 10) was not met, adjust bleed air valve rate control adjustment screw as follows:
NOTE: There are two configurations of rate control adjustment screw. Each requires certain precautions when making adjustments.
a) On airplanes with configuration 1 rate adjusting screw (Fig. 504, View 2).
1.
Loosen sleeved jamnut on rate control adjustment screw.
2.
Turn adjustment screw clockwise to increase opening time; turn adjustment screw counterclockwise to decrease opening time.
NOTE: If adjustment is difficult to make, contamination of needle valve may be problem - remove needle valve, wipe clean and reinstall. 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 机载辅助动力AIRBORNE AUXILIARY POWER(55)
