Accident Overview
On final approach to the destination airport, the airplane's engine stopped. The pilot immediately switched fuel tanks and turned on the fuel pump, but engine power was not restored. Realizing that the approach glidepath would put the airplane into trees, the pilot elected to land in a field short of the trees.
Investigation Findings
Continuity of the fuel system was confirmed. Physical evidence of contamination, including ferrous and nonferrous materials, was found throughout the fuel system—specifically in the fuel strainer, selector valve, electric fuel pump, left wing fuel cavity, and carburetor. This contamination indicated that water had been present at some time and was allowed to remain in the system. The engine was removed from the airframe, and during an engine run, no apparent anomalies were found.
Preflight Procedures
During preflight, the pilot must select each tank with the fuel selector valve and then individually drain it from the cockpit using the drain valve on the fuel selector. The individual tanks are not equipped with drain sumps. If a fuel tank that was not drained properly was selected during flight, water and/or contaminants could be introduced into the engine, causing a partial loss of power or engine stoppage.