ASK 21 hard landing during training at Gruyère Aérodrome after simulated cable break
On June 12, 1994, an Alexander Schleicher ASK 21 experienced a hard landing at Gruyère Aérodrome during a training flight. The instructor simulated a winch cable break shortly after takeoff, leading to a steep climb by the student pilot. The glider was brought back under control close to the ground, but a hard landing ensued. The instructor sustained serious injuries, while the student pilot had minor back pain. The glider's landing gear and airframe were damaged. The official report identified a stall near the ground and premature deployment of airbrakes as causes.
- Winch launch climb: During a dual training winch launch from runway 36, the ASK 21 transitioned from the initial acceleration into a steep climb of about 40° shortly after liftoff.
- Simulated cable break: At approximately 20 m above ground and 1–2 seconds after rotation into the steep climb, the instructor released the winch cable to simulate a cable break.
- Low altitude exercise: The cable break simulation was conducted at very low height near the start of the steep winch climb, leaving little altitude margin for recovery.
- Premature airbrake use: Airbrakes were observed extended shortly after the transition to glide, reducing acceleration and adding a nose-down pitching moment during the recovery.
- Student pushes nose down: The student immediately pushed the control stick forward to lower the nose and attempt to land ahead, causing the glider to pitch increasingly toward the ground.
- Instructor flare and stall: As the glider approached the ground in a steep descent, the instructor pulled the stick back sharply to arrest the sink, and the glider stalled at low height and sank almost flat onto the surface.
- Crash - serious injury: The glider impacted the ground very hard near the runway threshold, seriously injuring the instructor, slightly injuring the student, and damaging the landing gear and airframe.