Pilot Debrief

BEECH C23 near Duncan, OK — 2008-09-28

Final reportDEN08LA163
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Date
2008-09-28
Location
Duncan, OK, USA
Aircraft
BEECH C23
Registration
N6714E
Category
Airplane
Highest injury
Minor
Fatalities
0

Probable cause

A total loss of engine power due to the fatigue failure of the engine crankshaft. Contributing to the accident were the improper maintenance to the engine crankshaft, improper reassembly of the engine, and failure to follow the engine manufacturer's overhaul manual.

NTSB narrative

During the local flight, the airplane's engine began to violently shake and the pilot elected to shut down the engine and perform an emergency landing to a field. The airplane impacted a fence and terrain, which resulted in a bent firewall and left wing. A review of the maintenance records showed that, approximately 23 hours prior, the engine had experienced a loss of engine oil due to faulty maintenance during an annual inspection. The engine underwent maintenance and the airplane was returned to service. Examination and disassembly of the engine revealed that the crankshaft had fractured into 3 sections and that improper maintenance had been performed on several engine components. Metallurgical examination of the crankshaft revealed that the crankshaft had been improperly reworked which resulted in fatigue and crankshaft failure. The crankshaft rework and engine reassembly did not follow the manufacturer's overhaul manual.

NTSB coding

View NTSB final report

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