Primary finding
Probable cause
The airplane’s encounter with downdrafts resulting in decreased performance insufficient to outclimb rising terrain.
Investigator assessment
Analysis narrative
The pilot reported he encountered downdrafts during landing on a remote gravel airstrip near a glacial base camp known for downdrafts and mountain rotors. He elected to depart the airstrip into rising terrain due to more favorable winds. During initial climb out the pilot reported the airplane encountered more downdrafts than expected. Unable to outclimb rising terrain, the pilot performed a forced landing in an area of rough, rock-covered terrain, and during landing the airplane sustained substantial damage to the wings and fuselage. The pilot reported that there were no pre-accident mechanical malfunctions or failures with the airplane that would have precluded normal operation.