Primary finding
Probable cause
The failure of the no. Two cylinder connecting rod due to a slipped (spun) main crankshaft bearing which blocked off the oil hole to the connecting rod. A factor in the accident was the unsuitable terrain on which to perform a forced landing.
Investigator assessment
Analysis narrative
The engine failed about 5 to 6 minutes after takeoff during the climb to cruise phase of operation. The pilot made an off airport forced landing on an ice flow. At the time of the accident, the part 135 operator was repositioning the airplane under part 91. The cause of the engine failure was traced to a spun crankshaft bearing which blocked off the oil hole to the no. 2 cylinder connecting rod, resulting in its catastrophic failure. The spun bearing most likely was the result of either a loss of torque or insufficient torque being applied to the crankcase thru stud bolts.
Source record
Factual narrative
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