What happened
Following a weekend of skydiving operations, the pilot began preparing the aircraft for a return flight to the home base. Although the pilot had researched the upcoming route, which included predicted turbulence and icing, the departure was delayed in an attempt to ensure the flight could be conducted under visual flight rules (VFR). The accident took place at night under conditions of low lunar illumination and layered cloud cover.
During the flight, the aircraft encountered broken to overcast cloud layers both above and below its altitude. Radar data suggests the pilot was maneuvering the aircraft to avoid rain showers and clouds while attempting to remain in visual conditions. The aircraft likely entered clouds, turbulence, and potential icing during the final three minutes of the flight. While performing sequential 360-degree turns during a period of climbing and descending, the aircraft departed from controlled flight. A performance analysis indicated that the angle of attack was increasing rapidly, and the loss of control was consistent with an aerodynamic stall.
Prior to the accident, the unpressurized aircraft had been operating at altitudes exceeding 14,000 feet for more than one hour. The aircraft reached 15,000 feet shortly before the crash, and no supplemental oxygen was in use during the flight.
Findings
Investigation into the flight conditions revealed that the pilot was likely suffering from hypoxia due to the high altitude and lack of supplemental oxygen. At these elevations, the pilot would have been significantly impaired without experiencing noticeable symptoms. While the pilot was instrument rated, he had very limited experience with actual instrument flight. Furthermore, company policy restricted operations to VFR only, and the pilot had not undergone an instrument flight check.
- Aircraft altitude: Over 14,000 feet
- Flight conditions: Night, VFR attempt, encountering clouds and turbulence
- Pilot experience: 2,000 total hours, 300 hours in type, 2 hours actual instrument time