Fire and Overheat System Test
Fault/Inop detection ....................................................................... Check
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OVERHEAT DETECTOR switches - NORMAL
TEST switch - Hold to FAULT/INOP
Verify MASTER CAUTION, OVHT/DET annunciator, FAULT and APU
DET INOP lights are illuminated.
If the FAULT light fails to illuminate, the fault monitoring system is
inoperative. If APU DET INOP light fails to illuminate, do not operate APU.
Fire/Overheat warning ................................................................... Check
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TEST switch - Hold to OVHT/FIRE
Verify fire warning bell sounds, master FIRE WARN lights, MASTER
CAUTION lights and OVHT/DET annunciator illuminate.
Master FIRE WARNING light - Push Verify master FIRE WARN lights and
fire warning bell cancel.
Verify engine No. 1, APU, and engine No. 2 fire warning switch and engine
No. 1 and engine No. 2 OVERHEAT lights are illuminated. If AC busses are
powered, verify WHEEL WELL fire warning light is illuminated.
If an engine fire warning switch and an ENG OVERHEAT light do not
illuminate, a detection loop is inoperative.
Refer to Supplementary Fire and Overheat Test - Inoperative Loop procedure
in this section.
Extinguisher test ............................................................................ Check
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EXTINGUISHER TEST switch - Hold to 1
Verify the green extinguisher test lights are illuminated. Release switch and
verify the lights are extinguished. Repeat test for position 2.