TM 55-2840-254-23
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1-107 TEST ENGINE (AVIM) (Continued)
f. Position water back pressure master ydronic control fully open.
g. Press water brake pump, brake lube pump, and cooling tower start buttons and cooling fan forward
or reverse button (whichever is applicable). Supply 25 psig air pressure to water brake assembly. Check
torque panel, R/CAL, oil pump discharge pressure, compressor discharge pressure, gearbox pressure,
number 2 bearing pressure, fuel supply pressure, fuel control discharge pressure, fuel pump pressure,
and fuel manifold pressure.
h. Turn on start system on test stand.
In following step, hydraulic pressure drop across starter must not
exceed 3400 psig, if applicable. Damage to engine may result.
i. Simultaneously energize starter, igniters, and timer.
NOTE
All lever movements shall be made in 0.5 second or less.
j. At 10 to 15 percent N1 speed, set N1 master hydronic control to ground idle (15 degrees).
k. When power turbine inlet temperature is between 600 and 800 F (315 and 425 C), release ignition
switch. Continue to observe PTIT.
l. When 50 percent N1 speed is reached, release starter switch to OFF.
If start is aborted for any reason, wait 15 seconds after coastdown
before attempting a restart. Hot start may result.
m. Record acceleration time to 45 to 50 percent N1 speed.
n. Record maximum PTIT. Maximum power turbine inlet temperature shall not exceed 1720 F (938 C)
once nor shall it exceed 1450 F (788 C) for more than 5 seconds, three times. If limits are exceeded
Inspect Engine Hot End (Ref. Task 1-93) and determine cause for overtemperature (Ref. Task 1-32).
o. Turn off test stand start system.
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