Ka 6 collision during aerotow launch at Schänis airfield, Switzerland
On May 16, 1965, at Schänis airfield in Switzerland, two Alexander Schleicher Ka 6 CR gliders were involved in a collision during an aerotow launch. The incident occurred when the tow rope of the leading glider snapped due to a sudden tension, causing the trailing glider to collide with the leading one. The leading glider's wing was damaged, but there were no injuries reported. The event took place during a public flying event celebrating the opening of the Alpine Gliding School Schänis AG.
- Aerotow ground roll: During a public flying event at Schänis, two Ka-6 gliders were lined up in echelon for a dual aerotow behind a D-26 towplane and began the takeoff ground roll.
- Inadequate coordination: For this uncommon dual aerotow demonstration, there was no evidence of specific briefing or instruction given to the ground helpers on coordinated signaling and rope handling.
- Tow started too early: The wingman of the left-staggered leading glider HB-683 signaled for start, this was relayed to the tow pilot, and the towplane applied full power even though the rope segment to the rear glider HB-703 was not yet fully tensioned.
- Tow rope snaps: As the takeoff roll continued, the still-slack rope to HB-703 suddenly came tight with a sharp jerk and the tow rope failed in its forward third.
- Front glider releases, turns: The pilot of HB-683 immediately released his tow rope and rolled the glider onto the left wing to avoid being overrun by the towplane.
- Ground collision: HB-683 slewed left and its tail skid struck the already lowered left wingtip of HB-703, breaking the main spar of HB-703’s left wing.
- Hard landing - damage: The tow pilot aborted the takeoff before liftoff and both gliders remained on the ground, with HB-703 sustaining significant wing damage but no injuries to any occupants.