ASK 13 wing strikes tree on short final in gusty wind
An ASK 13 was substantially damaged on a training flight at Iserlohn-Suemmern (Germany); both occupants were seriously injured. After a winch launch the crew began final approach to RWY 23 in very gusty wind from 210-300 degrees at 10-22 kt. Witnesses saw the glider lower than usual; about 100-200 m before the threshold it deviated sharply right and the instructor reported the controls felt soft. The left wing struck a tree at 15 m, the glider rotated 270 degrees counterclockwise, and it impacted 40 m short of the threshold. The instructor held 1,969 h total but only 11 h on type, with 2.5 h since the start of the year.
- Winch launch RWY 23 12:57 LT: At 12:57 LT on 9 May 2015 an instructor and student launched an ASK 13 by winch from RWY 23 of Iserlohn-Sümmern for a circuit, turning right after release and then alternating turns.
- Gusty wind 210-300° / 10-22 kt: Wind was gusty and variable across a wide arc; the landing on RWY 23 lay within that variability.
- Instructor: 11 h on type, 1,969 h: The instructor had very limited recent experience on the ASK 13 type, and the student was at the beginning of training.
- Final approach 23, lower than usual: After about five minutes in the circuit the crew commenced the final approach to RWY 23. Witnesses noted that the glider was lower than usual on final.
- Sharp right deviation on short final: About 100 to 200 m before the runway threshold the glider made a marked change of direction to the right.
- Correction; controls feel "soft": The instructor reported that he tried to correct the unintended right turn and noticed that the controls of the glider felt "soft" — a feel consistent with airspeed near the stall.
- Wing strikes tree, 270° rotation: At about 15 m above the ground the left wing struck a tree at the airfield edge; the glider rotated about 270° and hit the ground short of the runway. Both occupants were seriously injured.