Unfall mit SZD-51-1 während Windenstart in Croix-de-Coeur, Schweiz

Am 6. August 1988 war ein Segelflugzeug vom Typ SZD-51-1 in einen Unfall während eines Windenstarts in Croix-de-Coeur, Schweiz, verwickelt. Das Segelflugzeug, gesteuert von einem Schweizer Piloten, hatte während der Beschleunigungsphase aufgrund eines starken Rückenwinds und einer unebenen Startbahn Schwierigkeiten. Das Segelflugzeug kam vom Kurs ab und konnte die Abhebegeschwindigkeit nicht erreichen, was zu einer Kollision mit dem Gelände führte. Der Pilot erlitt schwere Verletzungen, und das Flugzeug wurde stark beschädigt. Offizielle Untersuchungen bestätigten, dass die Windverhältnisse und der Zustand der Startbahn den Unfall beeinflussten.

1. Winch launch ground roll: During a test winch launch from the Croix-de-Coeur mountain landing site, the SZD-51-1 began its ground acceleration on a short, uneven, slightly downhill natural strip with a significant tailwind.
2. Glider yaws off axis: As the glider accelerated and passed over a bump where the slope changed, the off-axis winch cable routed via a pulley to the right of the runway caused the glider to yaw suddenly about 20–25° to the right.
3. High tailwind component: A tailwind of about 20 km/h reduced the effective airspeed gained during the limited usable ground run, making it harder to reach takeoff speed.
4. Degraded short runway: Only about the first 100 m of the 200 m natural strip were marginally usable, with the remainder increasingly rough and eroded, limiting acceleration and increasing drag and shocks.
5. Right-side pulley position: The winch cable was routed through a pulley positioned 13 m to the right of the runway axis, contrary to the flight manual requirement that the cable not pass to the right when using the central hook, creating a lateral pull on the glider.
6. Pilot continues launch: Believing liftoff was imminent after the yaw, the pilot chose not to release the winch cable and then, being violently shaken on the rough ground, was unable to operate the release and lost directional control.
7. Crash - serious injury: Still below flying speed and deflected off the strip, the glider was heavily braked by rough terrain, the cable broke, and the aircraft came to rest badly damaged in grass to the right of the runway, with the pilot seriously injured.