NTSB Identification: LAX97LA116.
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Accident occurred Sunday, March 02, 1997 in MORRISTOWN, AZ
Probable Cause Approval Date: 01/07/1998
Aircraft: Beech J35, registration: N39W
Injuries: 1 Serious,1 Minor.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

While in cruise flight the pilot felt a slight vibration and immediately made a power change without affect. After reducing the engine rpm from 2300 to 2100, the airplane vibrated hard for a split second and then smoothed out. At that point, the propeller had separated from the engine with part of the crankshaft. Metallurgical examination of the crankshaft revealed that the fatigue failure occurred inside the crankshaft bore 1.7 inches forward of the crankshaft oil seal. The point of origin was at two corrosion pits.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

failure of the crankshaft due to improper inspection/overhaul procedures.

Full narrative available

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