American Champion Aircraft 8KCAB N59SE accident near Alpine, Wyoming

Probable cause

The pilot’s inadvertent descent while operating in flat light conditions which resulted in controlled flight into terrain.

NTSB analysis

At the conclusion of an uneventful flight, the pilot returned to the departure airport and entered the airport traffic pattern. The pilot stated that after he turned onto the base leg for the runway, he unknowingly lost depth perception and flew into the snow-covered terrain due to the “flat light” conditions. During the accident sequence, the airplane nosed over, and sustained substantial damage to the rudder, vertical stabilizer, and both wings.

The pilot added that the terrain surrounding his base leg of the traffic pattern was a dry lakebed covered in snow, the sky was overcast, and there were no shadows. He further stated that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR26LA095 for the full record.