What happened
On May 10, 2001, a Jodel D-117, registration HB-SUL, was conducting a training flight near Birrfeld, Switzerland. The flight was intended to be a training session for the pilot to practice an emergency landing procedure. During the flight, the instructor simulated an engine failure by reducing power at an altitude of approximately 600 meters.
As the aircraft descended toward the Bremgarten area, the pilot maintained a speed significantly higher than the best glide speed. The instructor, observing the descent, attempted to guide the pilot toward a suitable landing field and prepared to issue a go-around command. However, at a very low altitude of approximately 30 to 50 meters, the pilot initiated an unexpected left turn toward a different field. This maneuver caused the aircraft to strike a tree and crash into a meadow. The pilot sustained fatal injuries and passed away later that evening, while the instructor survived the impact.
The investigation
The investigation examined the flight sequence, the technical condition of the Jodel D-117, and the communication between the crew. Investigators found that the aircraft was well-maintained and that the engine and flight controls were functioning correctly prior to the impact. While fuel contamination was detected, it was determined not to have contributed to the accident.
Regarding the crew, the investigation noted that the pilot had significant flight experience but had shown uncertainty during a previous approach to Birrfeld. The instructor, while experienced, was relatively new to this specific aircraft type. The investigation also reviewed the cockpit environment, noting that the aircraft was equipped with only lap belts and lacked shoulder harnesses.
Findings
- The primary cause of the accident was a loss of control at low altitude during an inappropriate emergency landing exercise.
- The instructor was caught by surprise by the pilot's sudden left turn and was unable to intervene or take corrective action.
- There was a significant lack of verbal communication between the pilot and the instructor during the critical phase of the maneuver.
- The instructor's decision to abort the exercise was made too late.
- The procedures for handling engine-out simulations lacked sufficient systematic structure to ensure safety during the training.