Amateur-built RV 6 accident near Viborg, South Dakota, September 2, 2016

The NTSB's narrative final · quoted from the NTSB record

The commercial pilot and the passenger, his 14-year-old granddaughter who wanted to become a pilot, were making a local flight in the airplane. No radar or GPS track information was found for the flight. A witness heard the airplane's engine "sputtering" before the airplane impacted the ground in a cornfield. A postimpact fire consumed the engine cowling, cockpit, fuselage, and the forward portion of the empennage. Damage to the airplane, the crop, and marks on the ground indicated that the airplane impacted in a slightly nose-low and left-wing-low attitude with no forward airspeed, consistent with a relatively flat spin. The propeller remained attached to the engine and was embedded in the soil and positioned horizontally. The propeller blades were slightly bent aft and did not exhibit any leading-edge damage, consistent with minimal, if any, power being produced by the engine during impact. No mechanical malfunctions or anomalies were found with the engine or airframe that would have precluded normal operation. However, the examination was limited by the extensive postcrash fire damage. The circumstances of the accident are consistent with the airplane exceeding its critical angle of attack, resulting in an aerodynamic stall and subsequent flat spin into terrain. Given the witness report of a "sputtering" engine and the propeller signatures consistent with the engine not producing power at impact, it is likely that the engine lost power before impact. However, it could not be determined whether the engine lost power before the loss of control or whether the pilot intentionally reduced power during the descent. The14-year-old passenger was seated in the left seat, and the pilot was seated in the right seat. Although the family reported that the flight was not instructional, it is possible that the pilot allowed the passenger to manipulate the flight controls. Regardless of which occupant was manipulating the flight controls, the pilot was the only certificated pilot on board and was responsible for the safety of the flight.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.