SZD-55 rolls into a parked aircraft after a wing drop on aerotow

During an aerotow at Bad Ragaz, an SZD-55-1 dropped a wing on the roll, ran off the runway, and hit a parked Mooney; pilot slightly injured, glider lightly damaged, Mooney substantially. On the pilot's seventh flight on type, as the towplane took up slack the right wingtip caught the grass; a factory-misfitted aileron lever had weakened roll control, so full stick couldn't raise the wing. He released the hook late and, with about three seconds left, did not brake; the unbraked glider ran ~100 m into the Mooney. Cited causes: the ground contact and excursion, the late release, the factory-weakened aileron, and the unused brake.

1. Aerotow takeoff roll: During an aerotow departure on runway 12, the SZD-55-1 began its takeoff roll in variable 5–10 kt wind for the pilot’s seventh conversion flight on type.
2. Misrigged aileron control: The right aileron drive lever had been incorrectly installed at the factory, giving both ailerons excessive positive setting and reducing roll control effectiveness.
3. Right wing contacts ground: Shortly after the towplane began to pull, the glider’s right wingtip touched the ground in the grass area beside the paved runway.
4. Veer off runway: The right wing was decelerated by the low grass and, despite full opposite aileron, the glider yawed and departed the hard-surface runway after about 30 meters.
5. Tow cable released late: After being unable to raise the wing, the pilot released the nose hook tow cable only after roughly 50 meters of ground run, by which time the glider was already off the runway.
6. Wheel brake not used: With only about three seconds remaining before impact, the pilot did not apply the wheel brake and the glider continued rolling unchecked toward a hangar.
7. Crash - minor injury: After a ground roll of about 100 meters, the unbraked glider collided heavily with a parked Mooney M20J, causing major damage to the Mooney, minor glider damage, and minor pilot injury.