What happened
During a for-hire sightseeing flight, a glider entered an inadvertulent stall and subsequently spun to ground impact. On the day of the accident, weather conditions were characterized by shifty and gusting winds that failed to produce the typical updrafts along the ridgeline usually present in the area. Additionally, cloud bases prevented towing operations above 2,000 feet.
A witness, also a glider pilot, observed the aircraft traveling eastbound approximately 400 to 500 feet above the ridge. The witness noted that the aircraft turned 45 degrees to the right toward the ridge and the nose pitched up slightly. The aircraft then turned back to the left and immediately entered a left spin. The witness reported seeing the glider rotate twice before it entered a second spin to the right.
Audio recordings from the final moments of the flight captured the pilot reporting that the aircraft was encountering a sink rate.
The investigation
A post-accident examination of the aircraft revealed no mechanical anomalies that would have prevented normal operation. A video recording of the flight also showed no issues with the aircraft.
An investigation into the pilot's training and experience found that the pilot had obtained a commercial pilot certificate less than three months after beginning flight training, only two days after passing the private pilot check ride. At the time of the accident, the pilot's total flight experience was 48.4 hours, with 31.2 hours as pilot-in-command. Training records indicated that stall and spin training was conducted on the same day as training for various other complex subjects. The operator noted that during a previous spin training session, the pilot failed to apply sufficient forward stick pressure during recovery, resulting in a secondary stall.
Findings
- The aircraft experienced an inadvertent stall and subsequent spin.
- Weather conditions lacked the expected ridge updrafts due to shifty, gusting winds.
- The pilot's training and experience levels were noted as being unusually rapid for a commercial certificate holder.