Primary finding
Probable cause
The pilot’s failure to maintain proper airspeed and his exceedance of the airplane’s critical angle of attack, which resulted in an aerodynamic stall.
Investigator assessment
Analysis narrative
The pilot departed from a river sand bar, and shortly after takeoff the airplane encountered an unexpected left quartering tailwind. The pilot reported that the airplane’s left wing stalled, which induced a spin at a low altitude. The airplane’s left wing and forward left fuselage impacted the shallow river water and sustained substantial damage. Since the accident, the airplane washed away in the river current and has not been located. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.