Amateur-built Vans RV-4 N999ZF accident near Cortland, Nebraska

Probable cause

The pilot's decision to intentionally maneuver at a low altitude and his failure to maintain adequate airspeed during the climbing right turn, which resulted in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall.

NTSB analysis

The private pilot and passenger were conducting a personal flight in the single-engine airplane. According to available radar data and an interview with the pilot's brother, the pilot completed several intentional low-altitude passes (at or below 100 ft above the ground) over his brother's property/residence. The pilot's brother, who witnessed the accident, stated that following the final low pass, the airplane pitched up into a climbing right turn. He stated that, during the climbing turn, the airplane suddenly pitched nose-down and descended rapidly. The airplane recovered briefly to a wings-level attitude before the wings rocked left and right and the airplane entered a descending right turn into terrain. A postaccident examination established that the airplane had crashed in a nose-low attitude and was destroyed by impact and postimpact fire damage. The examination did not reveal any anomalies that would have precluded normal operation of the airplane during the flight. Based on the witness description and the impact geometry, it is likely that the pilot did not maintain adequate airspeed during the climbing right turn, which resulted in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall at a low altitude. Due to the pilot's decision to intentionally maneuver at a low altitude, there was insufficient altitude to fully recover from the aerodynamic stall before impact.

Text from the NTSB. Open the NTSB docket for CEN16FA014 for the full record.