What happened
During a GPS-based circling instrument approach under instrument meteorological conditions, the pilot was operating at an airport with which they were familiar. As the aircraft reached the minimum descent altitude of approximately 600 feet mean sea level, the groundspeed decreased from 90 knots to 65 knots. Shortly after this deceleration, the flight path deviated sharply to the left, and the aircraft began a rapid descent.
Surveillance footage from nearby homes captured the final moments of the flight. One camera recorded the aircraft in a shallow left bank that transitioned into a steep bank before disappearing below the tree line. A second video showed the aircraft already in a steep left bank near treetop level, continuing to roll left until impact. The aircraft was flying beneath an overcast ceiling with visibility estimated at 2 statute miles due to mist. At the time of the deviation, the destination airport was still 3.5 statute miles to the northeast.
Findings
Post-accident investigations confirmed that there were no mechanical failures that would have prevented the aircraft from operating normally. Evidence from propeller signatures, witness accounts, and audio recordings indicated that the engines were producing power at the moment of impact. Medical examinations of the pilot determined that sudden incapacitation due to a known heart arrhythmia was not a factor in the crash. Additionally, while soot was found in the airways, this was attributed to smoke inhalation during the post-crash fire rather than an in-flight fire.
Data from surveillance and ADS-B tracking suggest that as the pilot leveled off near the minimum descent altitude, the airspeed dropped below the aircraft's stall speed. This led to an aerodynamic stall and spin that the pilot could not recover from. The investigation noted that the aircraft's stall speed likely ranged between 67 and 76 knots indicated airspeed.