KERSHAW, SC, USA
N390G
PIPER PA-32-260
THE PLT RPRTD THE ENG ABRUPTLY LOST ALL POWER DURING CRUISE. SUBSEQUENTLY, THE ACFT COLLIDED WITH TREES DURING A FORCED LNDG AT NIGHT & BOTH WINGS WERE TORN OFF. AN EXAM OF THE ENG REVEALED THAT THE CRANKSHAFT GEAR BOLT WAS LOOSE, AND THAT THE GEAR ALIGNMENT DOWL WAS SHEARED, WHICH HAD RESULTED IN A LOSS OF ENG GEAR TRAIN CONTINUITY. A METALLURGICAL EXAM REVEALED THE DOWEL PIN HAD FAILED FROM FATIGUE. ACCORDING TO THE OPERATOR'S MECHANIC, THE ENG HAD EXPERIENCED A SUDDEN STOPPAGE DUE TO A PROP STRIKE ABOUT 151 OPERATING HOURS BEFORE THE ACCIDENT. LYCOMING SERVICE BULLETIN #465 OUTLINED MANDATORY INSPECTION, MODIFICATION, AND ASSY PROCEDURES FOR THE CRANK GEAR TO BE COMPLIED WITH DURING OVHL, AFTER A PROP STRIKE OR WHEN EVER GEAR TRAIN REPAIR IS REQUIRED. ACCORDING TO THE MECHANIC, THE BULLETIN WAS NOT COMPLIED WITH AFTER THE PROP STRIKE.
FATIGUE FAILURE OF THE CRANKSHAFT DOWEL PIN. FACTORS RELATED TO THE ACCIDENT WERE: FAILURE OF MAINTENANCE PERSONNEL TO FOLLOW THE APPLICABLE SERVICE BULLETIN AND DARKNESS.
Source: NTSB Aviation Accident Database
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