Squawk Box

August 2017 Issue




Motoring

The following information is derived from the FAA’s Service Difficulty Reports and Aviation Maintenance Alerts.

Cessna 172RG Cutlass
Shorted Landing Gear Motor

While in cruise flight, pilot noticed smoke coming out from under instrument panel. Pilot aborted flight but noticed landing gear extension much slower than normal. Aircraft was placed on jacks and gear retracted. Pump motor (p/n 98811281) could be heard grinding and working very slowly. Pump motor was too hot to be touched. Battery was disconnected, aborting retraction. New pump and motor were installed.

Part total time: Unknown

Cessna A185F Skywagon
Failed Landing Gear Motor

Customer forced to land amphibious float-equipped airplane gear-up on floats. Found the coupling between the hydraulic motor (p/n 108BIC19CLB1V060) and pump had broken. Also noted the motor shaft very hard to turn. Found hydraulic reservoir very contaminated with unknown sludge.

Part total time: 200.0 hours

Cirrus SR22
Autopilot Servo Motor

Pilot reported autopilot inoperative and ailerons moving more freely than usual. Removing left aileron well inspection panel revealed the roll/aileron trim motor actuator arm bungee totally sheared off of motor drive shaft end; the bungee assembly was still attached. When the trim motor broke, the autopilot no longer could drive the travel limits stop to contact the limit switches, causing a/p computer to drop offline and not engage when commanded.

Part total time: 1459.0 hours

Diamond DA42 Star
Failed Stick Limiter Motor

Stick limiter replaced due to noisy/intermittent operation. Unit was disassembled and motor brushes found contaminated with grease. Grease is passing through seal from mechanical section of limiter to the electrical side of unit.

Part total time: 714.0 hours

Piper PA-24-260 Comanche 260
Failed Fuel Pump Motor

Electric fuel pump failed, causing smoke and burning smell in aircraft. Fuel pump is located below co-pilot’s feet. Pump had 27.2 total airframe hours of operation since o/h. Incident flight was pattern work, where pump operated for 30 minutes.

Part total time: 27.2 hours

Piper PA-31 Navajo
Improper Flap Motor

New flap motor identified and certified as p/n 1202-00-1 failed shortly after installation. Motor may have been set up at overhaul as a 12-volt unit (p/n 1202-20-1), since both part numbers were indicated on unit. Motor failed after approximately 45 complete flap cycles in a skydiving operation.

Part total time: Unknown