Pilot Experiences Engine Failure During Landing After Water Contamination (N4721U)

Incident Sequence

The certificated commercial pilot moved the airplane from a hangar and sumped the wing fuel tanks. The airplane remained outside for the entire day as the ambient temperature warmed. No additional sumping of the wing tanks was performed. After takeoff, the pilot reduced engine power to level off at the airport traffic pattern altitude. The engine began to run rough, prompting the pilot to initiate an emergency landing approach to a snow-covered airstrip near the approach end of an asphalt runway. The engine roughness subsided, and air traffic control cleared the pilot to land on the larger asphalt runway. Shortly thereafter, the engine quit. The airplane touched down in an area of snow situated between the end of the small airstrip and the beginning of the asphalt runway. The airplane nosed over during the landing, resulting in damage to the vertical stabilizer, the rudder, and the left wing lift strut.

Examination Findings

An examination of the airplane revealed a wrinkle in the left wing fuel bladder. Additionally, 3 ounces of water were found in the gascolator.