NTSB Identification: SEA05LA049.
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Accident occurred Wednesday, February 16, 2005 in Roseburg, OR
Probable Cause Approval Date: 10/27/2005
Aircraft: Mooney M20K, registration: N1147D
Injuries: 3 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 pilot reported that shortly after takeoff, while in a climb configuration, the airplane's engine began to lose manifold pressure and engine RPM. Concurrent with the loss of engine power, the pilot noted a loss of oil pressure and elected to land the airplane, off-airport, in a wooded area. Post accident examination of the engine revealed that the distal end of the number 5 piston pin was fractured. Further examination revealed that the inner aluminum piston pin insert fractured-off just inboard of where the pin begins to taper outward. The fracture face was flat and perpendicular to the outer surface of the steel housing. Both fracture surfaces (inner and outer) sustained extensive smearing type damage and metal loss so significant that an analysis of the fracture surfaces could not be completed. Heavy scoring was noted to the wall of the number five cylinder assembly and piston. Extensive mechanical damage was observed to the relief area of the piston. The bottom piston ring was seized in place. Removal and examination of the oil sump revealed that the sump contained oil, as well as a large amount of metallic type particles. The oil pickup tube and screen was intact and also contained a significant amount of metallic like particles similar to the material found in the oil sump. The amount of metallic particles in the pickup tube and screen was sufficient enough to restrict the oil flow passage. The metallic particles were non-magnetic.

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

A fractured piston pin that resulted in a loss of engine power and subsequent forced landing. Factors include rough/uneven mountainous terrain.

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