Ka 4 Rhönlerche II stall during winch launch at Schänis airfield in poor visibility

On August 22, 1966, a training flight involving an Alexander Schleicher Ka 4 Rhönlerche II experienced a winch launch failure at Schänis Airfield, Switzerland. During the launch, the weak link of the towline broke, leading the student pilot to initiate a left turn in reduced visibility due to rain. The glider stalled due to insufficient speed, resulting in a crash with the left wingtip and fuselage impacting the ground. Both occupants sustained minor injuries, and the glider was heavily damaged, with damage assessed at 60% of its value.

1. Winch launch training: During a training flight, the Rhönlerche II began a winch launch from Schänis airfield in rainy conditions.
2. Weak link failure: During the winch launch, the weak link (Sollbruchstelle) of the towline broke, interrupting the launch.
3. Rain-reduced visibility: Visibility was strongly impaired by rain, making situational assessment more difficult for the student pilot.
4. Low-speed left turn: Following the towline break, the student pilot initiated a left turn despite having insufficient airspeed.
5. Stall over left wing: Because of the inadequate speed in the turn, the glider stalled over the left wing and descended uncontrollably.
6. Crash - minor injury: The glider struck the ground with its left wingtip and fuselage on the airfield, lightly injuring both occupants and causing heavy damage assessed at 60% of its value.