NTSB Identification: ANC98LA140.
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Accident occurred Sunday, September 06, 1998 in FAIRBANKS, AK
Probable Cause Approval Date: 03/30/2000
Aircraft: Cessna 140, registration: N81045
Injuries: 2 Uninjured.
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 heard a 'clunk' and engine rpm immediately began to decrease. The engine noise and rpm decrease continued, the pilot performed a forced landing in tundra, and the airplane nosed over onto its back. Postaccident inspection revealed that the exhaust valve stem of the number two cylinder had separated, and the valve was ingested into the cylinder. The engine had accumulated 4,555 hours since new, and 1,089 hours since overhaul.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The loss of engine power due to an in-flight fracture of an engine exhaust valve stem assembly. A factor associated with the accident was the lack of suitable terrain for a forced landing. Full narrative available
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