NTSB Identification: WPR10LA196
14 CFR Part 91: General Aviation
Accident occurred Sunday, April 04, 2010 in Leavenworth, WA
Probable Cause Approval Date: 06/20/2011
Aircraft: CESSNA P210N, registration: N3599P
Injuries: 1 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.

The airplane was in a cruise flight configuration when the engine ceased operating without warning. The pilot made an emergency descent and the airplane collided with a fence while landing in a field. Disassembly of the engine revealed extensive mechanical damage to the number two cylinder combustion chamber and piston assembly. The exhaust valve seat insert was missing and fragments of the insert were later found in the oil sump. The exhaust valve head had separated from the valve stem. The intake valve head had approximately 50 percent of the material separated. The fracture surfaces on the exhaust valve, intake valve and exhaust valve seat were damaged such that the mode of fracture could not be definitively determined. Hardness testing of the components indicted that they were within the manufacturer’s prescribed specifications. The sequence of fractures and separations of components could not determined.

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

The failure of the number two cylinder exhaust and intake valves for undetermined reasons, which resulted in a loss of engine power.

Full narrative available

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