TROUBLESHOOTlNG GUIDE F

TM 55-1510-218-MTF

TROUBLESHOOTlNG GUIDE F - PROPELLERS

CONDlTION

PROBABLE CAUSE

F1. Propeller governor system partially or wholly in-

operative.

a. Defective blocking diode on propeller gover-

nor test switch.

b. Defective propeller governor test panel.

c. Defective arc suppression capacitor or diode

on propeller reset or governor test solenoid.

F2. Propeller governor test system inoperative.

a. Tripped propeller governor test circuit

breaker.

b. Defective wiring.

F3. Propeller governor test system inoperative on

one engine.

a. Defective propeller governor system test

switch.

F4. Propeller autofeather system inoperative (propel-

ler autofeather switch in ARM or TEST posi-

tion).

a. Tripped circuit breaker.

b. Defective arming light out relay or feather-

ing relay.

c. Defective arc suppression diode on relays or

feather dump valve.

d. Defective ground blocking diode.

F5. Autofeather circuit breaker trips (autofeather

switch in ARM or TEST position).

a. Defective ARM-TEST switch.

b. Defective wiring.

F6. One autofeather arm light illuminates when

power setting is less than 90 percent N1 (AU-

TOFEATHER switch in ARM position).

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