1-1 FAILURE SYMPTOM LIST (Continued)
TM 55-1520-240-T
SYMPTOM
TASK
SYMPTOM
TASK
SYMPTOM
TASK
CHAPTER 15
AUXILIARY POWER UNIT
APU CONT NORM OR APU CONT EM ERG
CIRCUIT BREAKER DOES NOT STAY CLOSED
ESU BITE INDICATORS DO NOT CYCLE AFTER
APU SWITCH SET TO RUN
APU FUEL BOOST PUMP CANNOT BE HEARD
OPERATING BEFORE APU SWITCH SET TO
START
APU DOES NOT MOTOR WHEN APU SWITCH
SET TO START
APU ON CAPSULE GOES OUT (APU SHUTS
DOWN) WHEN APU CONT CIRCUIT BREAKER
OPENED
APU DOES NOT STOP. ESU BITE
INDICATES
APU ON CAPSULE OUT WHEN APU
OPERATING NORMALLY
APU SHUTS DOWN WHEN GEN APU SWITCH
PLACED TO ON. ESU BITE
INDICATES
15-2.7
15-2.8
15-2.9
15-2.10
15-2.11
15-2.12
15-2.13
15-2.14
APU SHUTS DOWN WHEN APU GEN SWITCH
IS SET TO OFF. ESU BITE INDICATES
APU MOTORS BUT DOES NOT START, ESU
BITE
INDICATES
THEN
(FAILURE TO START)
APU MOTORS BUT DOES NOT START, ESU
BITE
INDICATES
THEN
(FAILURE TO START)
APU START ACCUMULATOR GAGE DOES NOT
INDICATE AT LEAST 2850 PSI
APU DOES NOT MOTOR
APU MOTORS BUT DOES NOT START, ESU
BITE
INDICATES
OR
APU PUMP FAULT LIGHT IS ON
NO. 1 OR NO. 2 ENGINE DOES NOT MOTOR
(HYDRAULIC SYSTEM)
NO. 1 OR NO. 2 ENGINE KEEPS MOTORING
WHEN ENGINE START SWITCH SET TO OFF
15-2.15
15-3.6
15-3.7
15-4.9
15-4.10
15-4.11
15-4.12
15-5.6
15-5.7
APU MOTORS BUT DOES NOT START, ESU
BITE
INDICATES
(NO
SPEED
DATA)
APU MOTORS BUT DOES NOT START, ESU
BITE
INDICATES
OR
THEN
(FAILURE
TO
START)
APU MOTORS BUT DOES NOT START, ESU
BITE
INDICATES
THEN
(FAILURE TO START)
APU STARTS BUT SHUTS DOWN, ESU BITE
INDICATES
(OVERSPEED)
APU STARTS BUT SHUTS DOWN, ESU BITE
INDICATES
(UNDERSPEED)
APU STARTS BUT SHUTS DOWN, ESU BITE
I N D I C A T E S ( O V E R T E M P E R A T U R E )
APU STARTS AND RUNS THEN SHUTS DOWN,
ESU BITE INDICATES
(OVERTEMPERATURE) (HOT START)
APU STARTS BUT SHUTS DOWN, ESU BITE
I N D I C A T E S O P E N T H E R M O C O U P L E )
APU STARTS AND RUNS BUT ESU BITE
INDICATES (SHORTED THERMO
PROBE) (WARNING)
15-6.11
15-6.12
15-6.13
15-6.14
15-6.15
15-6.16
15-6.17
15-6.18
15-6.19
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Change 6
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