Landing gear (hydraulic) pump motor continues to run after the gear is retracted, causing the circuit breaker to trip.

TM 55-1510-218-MTF

C20. Landing gear (hydraulic) pump motor continues

to run after the gear is retracted, causing the cir-

cuit breaker to trip.

a. Pressure switch not opening on high pres-

sure.

b. Low accumulator charge.

c. Excessive fluid leakage past the piston seals

in the actuators.

d. Defective valve in the power pack.

C21. Landing gear (hydraulic) pump motor continues

to run after the gear are extended, causing the

circuit breaker to trip.

a. Downlock switches are not opening.

b. Power relay points stuck.

C22. Landing gear (hydraulic) pump motor continues

to run when the gear is extended or retracted,

causing the circuit breaker to trip.

a. Weak power pack motor.

b. Low voltage to the motor.

c. Low fluid level.

d. Blockage in the hydraulic system.

C23. Landing gear (hydraulic) pump motor operating

longer than 23 seconds in both the extension and

retraction modes. The 2-ampere circuit breaker

does not trip.

a. Low voltage.

C24. Landing gear (hydraulic) pump motor operating

longer than 23 seconds in the retract mode, but

the 2-ampere circuit breaker does not trip.

a. Faulty time delay PCB and pressure switch.

C25. Landing gear (hydraulic) pump motor operating

longer than 23 seconds in the extended mode

but the 2 ampere circuit breaker does not trip.

a. Downlock switches failing to open and/or

the time delay PCB is faulty.

3-10