L-13 Blaník drops onto the runway after a simulated winch failure at about 15 m

During a winch-launch emergency exercise at Mladá Boleslav, the student and instructor of an L-13 Blaník were unhurt when, after a pre-arranged winch power cut at about 15 m, the glider sank and struck the runway very hard; it was substantially damaged. The instructor had asked the winch driver for two cuts below 50 m for a land-ahead; the first came at about 30 m and the instructor demonstrated the land-ahead. On the next launch the power was cut at about 15 m in the steady climb. The student at once pushed the stick forward and released the cable, but the glider sank onto RWY 34 without airbrakes and rolled about 42 m.

1. Winch-launch emergency exercise: A student in glider-licence training flew the winch-launch emergency exercise with an instructor, practising a land-ahead after a winch power loss. Launches were from RWY 34.
2. Two cuts below 50 m arranged: The instructor asked the winch driver by phone for two power cuts below 50 m for a land-ahead. The first came at about 30 m, and the instructor demonstrated the land-ahead.
3. Winch power cut at about 15 m: On the next launch, in the steady climb after the rotation, the winch driver cut the power at about 15 m AGL; the surface wind was a variable crosswind.
4. Stick forward, cable released: The student at once pushed the stick forward to gain speed and released the cable, a response the instructor judged correct in principle.
5. Glider sinks onto the runway: The glider sank at low speed, and neither pilot could stop it; it struck the runway very hard without airbrakes. The winch driver saw a large flex of the wings.
6. Hard impact on RWY 34: The glider stopped about 42 m further on, short of the runway intersection. Fuselage skin, floors and the gear mounting were deformed or cracked; neither occupant was hurt.