VERO BEACH, FL, USA
N8156E
PIPER PA-28-181
WHILE ON A SHORT CROSS COUNTRY FLT, THE ENG QUIT. THE PLT WAS UNABLE TO RESTART THE ENG. DURING THE FORCED LANDING ON A ROAD, THE ACFT COLLIDED WITH A TREE THEN A GUARDRAIL. EXAM OF THE ENG REVEALED THAT THE CRANKSHAFT GEAR WHICH DRIVES TWO CRANKSHAFT IDLER GEARS WHICH IN TURN DRIVES EACH MAGNETO DRIVE GEAR FAILED TO DO SO WHEN THE BOLT WHICH SECURES IT TO THE CRANKSHAFT BACKED OUT ABOUT THREE TURNS. THIS WAS DUE TO A FOREIGN OBJECT LOCATED UNDER THE GEAR FOR AN UNDETERMINED TIME. THE LOOSE BOLT RESULTED IN THE TORQUE FROM THE CRANKSHAFT BEING TRANSMITTED TO THE CRANKSHAFT ALIGNMENT DOWEL, WHICH IS A NON-LOAD CARRYING MEMBER. THE ALIGNMENT DOWEL FAILED DUE TO FATIGUE RESULTING IN THE TOTAL LOSS OF ENG POWER. THE FOREIGN OBJECT WAS REPORTEDLY NOT LOCATED. REVIEW OF THE ENG LOGBOOKS REVEALED THAT THE ENG WAS OVERHAULED 1,574 HRS EARLIER.
FAILURE OF MAINTENANCE PERSONNEL TO FOLLOW DIRECTIONS OF A SERVICE BULLETIN DURING THE MAJOR OVERHAUL OF THE ENGINE. THIS RESULTED IN FAILURE TO DETECT A FOREIGN OBJECT UNDER THE CRANKSHAFT GEAR. AS A RESULT THE CRANKSHAFT GEAR BECAME LOOSE AND QUIT TURNING RESULTING IN THE TOTAL LOSS OF ENGINE POWER.
Source: NTSB Aviation Accident Database
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