NTSB Identification: WPR10LA424
14 CFR Part 91: General Aviation
Accident occurred Sunday, August 22, 2010 in Lakeview, OR
Probable Cause Approval Date: 12/20/2010
Aircraft: GRUMMAN AMERICAN AVN. CORP. AA-5A, registration: N26118
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.

The pilot reported that the preflight run-up was uneventful. Shortly after takeoff, at approximately 150 feet above ground level, the engine suddenly dropped rpm; the pilot verified fuel quantity, and attempted to lean the engine. Despite the pilot’s efforts, the problem persisted, and he initiated a forced landing into a nearby field. During the landing roll, the airplane’s left wing struck a fence post, and its empennage collided with high sage brush. Examination of the engine by a certificated airframe and powerplant (A&P) mechanic revealed low compression within the number three cylinder. Further examination revealed that the exhaust valve was stuck in the full open position. The examination revealed no further anomalies with the cylinder assembly or engine.

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

A partial loss of engine power during the initial climb due to a stuck exhaust valve.

Full narrative available

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