The pilot reported that he was hired to make a predator control flight. After completing a right turn to the west, he initiated a climbing left turn to the east and about 75 feet above the ground, the Piper PA18 “banked violently to the right and back to the left about two-three times,” descended and hit the snow-covered ground near Wyndmere, N.D.
The airplane sustained substantial damage to the right wing.
The hiring agency check pilot reported that during a post-accident flight review with the pilot, he did not apply rudder inputs during turns, steep turns, and stall recovery.
Probable Cause: The pilot’s exceedance of the airplane’s critical angle of attack during an uncoordinated turn while maneuvering at low altitude, which resulted in an aerodynamic stall.
This March 2019 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.