Primary finding
Probable cause
The pilot's failure to maintain clearance from the ground during low-level maneuvering in mountainous/hilly terrain.
Investigator assessment
Analysis narrative
The pilot reported that he was practicing the procedures for making approaches to back-country remote airstrips and was flying in approach configuration about 40 to 60 feet over a mountain ridge. Although the wind was light and variable, just as the airplane was crossing the ridge it encountered a downdraft, which resulted in a sudden loss of altitude. Before the pilot was able to correct the descent, one of the airplane's main landing gear tires came in contact with the snow-covered terrain, which resulted in the airplane slowing down and flipping over onto its back. The accident sequence resulted in damage to the top of the rudder and to one of the wing lift struts. The pilot reported no mechanical failures or malfunctions with the airplane at the time of the accident.
Source record
Factual narrative
The pilot reported that he was practicing the procedures for making approaches to back-country airstrips, and was flying in approach configuration about 40 to 60 feet over a mountain ridge. Although the wind was light and variable, just as the flight was crossing the ridge, the airplane encountered a downdraft which resulted in it suddenly losing altitude. The pilot stated that before he was able to correct the situation, one of the airplane's main gear tires came in contact with the snow-covered terrain, which resulted in the airplane slowing down and flipping over onto its back. The accident sequence resulted in damage to the top of the rudder and to one of the wing lift struts. The pilot reported no mechanical failures or malfunctions with the airplane at the time of the accident.