ASK 21 yaws and impacts ground after wingtip drop on winch ground roll

An ASK 21 was substantially damaged and one occupant suffered minor injuries when the left wingtip dropped during a winch ground roll; the glider yawed violently, briefly lifted off and impacted nose-down. The pilot — an experienced instructor with a passenger — launched on RWY 12 in light, aligned wind. The glider rotated around its vertical axis, turned ~150° and from about 2 m struck the ground at ~30–45° pitch, coming to rest 130 m from the launch point with structural damage to forward fuselage and empennage and a destroyed canopy. A dislodged elevator-linkage sleeve was found post-impact but ruled out as a cause.

1. Winch launch on RWY 12, 2 POB: An ASK 21 with two persons on board began a winch launch in direction 120° at Fischbek in light, aligned wind.
2. Left wingtip touches ground: During the initial ground roll the glider's left wingtip contacted the ground.
3. Violent yaw, brief liftoff: The glider rotated violently around its vertical axis, briefly became airborne and turned about 150° before descending.
4. Nose-down impact from ~2 m: From a height of about 2 m the glider struck the ground with the forward fuselage at an estimated 30–45° pitch attitude.
5. Elevator linkage sleeve ruled out: Post-impact inspection found a sleeve from the Wedekind safety pin dislodged in the elevator linkage; this was ruled out as a cause.
6. Stopped 130 m from launch — minor injury: The glider came to rest about 130 m from the launch point with structural damage to the forward fuselage and empennage and the canopy destroyed; one occupant sustained minor injuries.