What happened
During a flight intended to demonstrate the capabilities of a twin-engine airplane to a prospective buyer, the aircraft was performing power-off stall maneuvers at an altitude of roughly 1,000 feet. An observer noted that the initial stall and subsequent recovery were executed successfully. However, during the second attempt, the aircraft's nose ascended higher than the previous maneuver, leading to a drop in the right wing and a sharp descent. The aircraft completed approximately one and a half rotations before obscured by trees.
Data from radar and performance analysis showed the aircraft departed from the airport and underwent various changes in altitude, speed, and heading before impacting the ground 14.6 nautical miles east of the departure airfield. Although the engines were heard increasing in power just before the impact, the aircraft failed to maintain controlled flight.
Findings
An investigation into the aircraft's performance revealed that the calibrated airspeed was trending toward and dropping below the established stall speeds, which were 71 knots with flaps retracted and 63 knots with flaps extended. The aircraft's airspeed fell below the required thresholds for safe flight during the maneuvers. Post-accident inspections of the engines and the airframe revealed no evidence of mechanical failure or structural damage.