Amateur-built SA6B N3129 accident near Los Olivos, California

Probable cause

A loss of engine power for undetermined reasons. Contributing to the accident was the pilot's improper decision to depart from a road with a known unresolved engine problem.

NTSB analysis

During a local area flight, the experimental airplane's engine began sputtering. The pilot attempted to rectify the situation by changing fuel tanks, applying carburetor heat, and checking the magnetos. His actions were unsuccessful, and all power was lost. The pilot made a forced landing on a public road. Thereafter, the pilot consulted with a mechanic at his home base airport that was located about 7 miles from the forced landing site. The pilot opined that vapor lock was a likely cause for his loss of engine power. In preparation for takeoff from the road, the pilot performed an engine run-up. The engine appeared to operate normally, and the pilot proceeded to takeoff. Seconds after becoming airborne and gaining at most 50 feet of altitude, the engine again started sputtering. The road curved away from the pilot's flight path, and the pilot opted to descend into trees. The airplane was subsequently recovered and was examined under Federal Aviation Administration (FAA) supervision. The FAA coordinator reported that no external evidence of a preimpact engine malfunction or anomaly was noted. The engine lost power for undetermined reasons.

Text from the NTSB. Open the NTSB docket for WPR09LA082 for the full record.