Amateur-built KITFOX IV N921RP accident near De Smet, South Dakota

Probable cause

The pilot's failure to maintain adequate airspeed and his exceedance of the airplane's critical angle-of-attack during a steep turn at a low altitude, which resulted in an aerodynamic stall/spin at too low of an altitude to recover.

NTSB analysis

During a personal local flight, the private pilot and passenger, who held a student pilot certificate, were searching a lake for a submerged boat. The passenger stated that while maneuvering at a low altitude, the pilot banked the airplane about 45 to 60 degrees at an airspeed of about 50 miles per hour. During the turn, the airplane stalled, entered a spin, and impacted the water. A postaccident examination of the airframe and engine did not reveal any evidence of a mechanical malfunction or failure that would have precluded normal operation. Data from a GPS unit recovered from the airplane indicated that the airplane was about 250 ft above ground level at a ground speed of about 34 knots when it stalled. Based on the passenger's statements and the GPS data, it is likely that the pilot failed to maintain adequate airspeed and exceeded the airplane's critical angle-of-attack while maneuvering, which resulted in an aerodynamic stall/spin from which he had insufficient altitude to recover.

Text from the NTSB. Open the NTSB docket for CEN16FA209 for the full record.