Amateur-built CHALLENGER II N9103L accident near Moses Lake, Washington

Probable cause

A loss of engine power during the initial climb for reasons that could not be determined because postaccident examination did not reveal any anomalies that would have precluded normal operation.

NTSB analysis

The pilot and the flight instructor were in the process of starting the climb after takeoff in the airplane that the pilot had recently purchased. As they started to turn toward the practice area, the airplane’s water-cooled engine suddenly began to overheat. The pilots therefore initiated a turn back toward the airport, but the engine started losing power. Because it appeared that they would not be able to make it to the airport, the flight instructor took over and landed the airplane in a nearby soft field covered with a crop of wheat. During the landing roll, the airplane nosed over and a fire began, which eventually consumed much of the airframe structure and engine components. Although the engine cooling system was missing a mandatory cooling system vent line, the teardown examination did not reveal any evidence of overheating or component seizure in the engine’s top end. The investigation also determined that the failure of the crankshaft to rotate after the accident was due to the postaccident melting and subsequent solidification of the phenolic MAG bearing cages due to the postimpact fire. The investigation was unable to determine the reason for the loss of engine power.

Text from the NTSB. Open the NTSB docket for WPR11LA291 for the full record.