Primary finding
Probable cause
The pilot’s inability to maintain altitude during an initial climbout in mountainous terrain after encountering a suspected downdraft.
Investigator assessment
Analysis narrative
The airplane departed a private dirt strip in mountainous terrain with a left quartering headwind. During the initial climb, the pilot retracted the flaps from to 20º to 10º to improve the airplane’s acceleration. There was no change in airspeed, so he retracted the flaps completely and the airplane began a descent. He then extended the flaps back to 10º and initiated a shallow right turn to maneuver away from rising terrain, but the airplane did not climb. The pilot applied a nose down attitude to prevent a stall and the airplane impacted terrain and nosed over, in which the right wing sustained substantial damage. The pilot suspected he had flown into a downdraft after taking off and reported there were no mechanical failures or malfunctions to the airplane or engine that would have precluded normal operation.