ASK 21 stalls near ground recovering a low simulated cable break
During dual winch-launch training at Gruyère, an ASK 21 instructor was seriously injured and the student slightly; the glider was substantially damaged. About 1-2 s after the student rotated into a ~40° climb, near 20 m AGL, the instructor released the cable to simulate a break. The student pushed the nose down too far and the glider kept pitching toward the ground, the airbrakes coming out prematurely. With the ground close, the instructor pulled back hard; still below flying speed, the glider stalled and sank flat onto the runway. The causes: a stall near the ground during a low cable-break simulation, and premature airbrake extension.
- 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, and it stalled at low height and sank nearly 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.