WEST PALM BEACH, FL, USA
N4188S
BEECH 58
AFTER ARRIVING IN THE TRAFFIC PATTERN OF THE DESTINATION ARPT, THE PLT LOWERED THE LANDING GEAR SELECTOR HANDLE BUT THE GEAR DID NOT EXTEND. THE FLT DEPARTED THE PATTERN & ATTEMPTS TO LOWER THE GEAR VIA THE EMERGENCY METHOD WERE UNSUCCESSFUL. THE FLT DIVERTED TO A LARGER ARPT WHERE A GEAR UP LANDING OCCURRED. THE LANDING GEAR RETRACT MOTOR & GEARBOX ASSY WAS REMOVED FROM THE ACFT & DISASSEMBLY REVEALED THAT THE WORM SECTOR GEAR REPEATEDLY CONTACTED THE SECTOR GEAR STOP. ALSO, TWO HALF RINGS WHICH SECURE THE BEARING TO THE WORM ACTUATING SHAFT SHEARED. THIS ALLOWED THE WORM GEAR ACTUATOR TO TRAVEL TOWARD THE MOTOR. AS A RESULT, THE HAND CRANK ENGAGING SHAFT WOULD NOT CONTACT THE WORM GEAR ACTUATOR. ACCORDING TO A MECHANIC, THIS WAS DUE TO A WORN LANDING GEAR MOTOR WHICH WOULD DRIVE THE GEAR BUT WOULD RENDER THE DYNAMIC BRAKING ACTION INOPERATIVE. THE UP-LIMIT SWITCH WAS TESTED & FOUND TO OPERATE NORMALLY.
PARTIAL FAILURE OF THE LANDING GEAR MOTOR WHICH CAUSED INTERNAL DAMAGE TO THE LANDING GEAR RETRACT MOTOR AND GEARBOX ASSY.
Source: NTSB Aviation Accident Database
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