TM 55-1510-221-MTF
a.
Defective or out of adjustment power switch
F7.
Neither autofeather arm light illuminates when power levers
are advanced (AUTOFEATHER switch in ARM position).
a.
Defective autofeather switch
F8.
One arm light does not illuminate when power levers are
advanced (AUTOFEATHER switch in ARM position).
a.
Defective or out of adjustment power switch.
b.
Defective No 1 (12 PSI) torque pressure switch
F9.
Both arm lights remain illuminated when one power lever is
retarded (AUTOFEATHER switch in ARM position).
a.
Defective or out of adjustment power switch
F10.
Propeller does not start to feather after engine torque falls
below 7% (AUTOFEATHER switch in ARM position).
a.
Defective No. 2 (6 5 PSI) torque pressure switch on retarded
engine
b.
Defective autofeather dump valve
F11.
One arm light does not illuminate when power levers are
advanced to 90 percent N1 (AUTOFEATHER ARM-TEST
switch in TEST position).
a.
Defective No. 1 (12 PSI) torque pressure switch.
F12.
Both arm lights extinguish when one power lever is
retarded (engine torque 7 to 12% on retarded engine,
AUTOFEATHER ARM-TEST switch in TEST position).
a.
Defective No 2 (6 5 PSI) torque pressure switch on retarded
engine
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