What happened
On September 21, 2006, a Schweizer 2D69C helicopter, registered as HB-ZHU, was involved in a fatal accident at Bern-Belp Airport. The pilot, who was acting as a course instructor for a flight instructor training program, was performing solo training maneuvers during a midday break.
After conducting several low-level exercises, the pilot initiated a simulated autorotation. During the final approach phase, the pilot attempted to correct a low airspeed by lowering the nose. As the aircraft reached an altitude of approximately 10 meters, the pilot attempted to increase engine power and pull the collective pitch to cushion the landing. During this maneuver, the pilot noted a vibration and a sudden increase in the rate of descent. The helicopter struck the ground with a high rate of descent, causing the tail rotor to detach and the main rotor blades to separate upon impact. The aircraft was destroyed, and the pilot sustained one serious injury.
The investigation
The investigation examined the pilot's recent flight history, the aircraft's maintenance records, and the operational circumstances surrounding the training course. Investigators found that the pilot had not flown the HB-ZHU type for over three months and had primarily operated the aircraft in an examiner capacity rather than as a pilot.
Technical inspections of the Schweizer 269C revealed no mechanical failures or prior technical issues that could have caused the accident. The investigation also noted that while other qualified instructors were available for the afternoon flight service, the pilot chose to conduct the training flight alone to manage his workload and utilize his break time.
Findings
- The primary cause of the accident was the loss of control of the helicopter during a solo training autorotation.
- A lack of recent, hands-on training on this specific aircraft model contributed to the accident.
- The pilot's health status at the time of the flight was identified as a contributing factor.
- Increased workload, stemming from the pilot's dual responsibilities as a course manager and instructor, influenced the decision to fly the maneuver alone.