Ka 4 Rhönlerche II incident during training flight at Fricktal Schupfart airfield

On June 6, 1970, a Ka 4 Rhönlerche II experienced an incident during a training flight at Fricktal Schupfart airfield, Switzerland. The glider, carrying a flight instructor and a student, was being towed by a motor aircraft when the towline unexpectedly released at approximately 50 meters altitude. The instructor attempted a turnaround maneuver, resulting in an uncontrolled landing between a hangar and parked aircraft. Both occupants were uninjured, but the glider sustained significant damage. The cause of the towline release was not determined.

1. Aerotow initial climb: During an instructional aerotow from runway 08, the Rhönlerche II with student in front and instructor in the rear climbed normally after takeoff in gusty Bise conditions.
2. Turbulence and crosswind: At about 30 m above ground the glider was hit by a gust causing a strong right bank, requiring instructor intervention after the student’s inadequate correction.
3. Student currency gap: The student’s last glider flight had been almost a year earlier, reducing recency for handling and emergency response.
4. Towline releases low: At about 50 m above ground and roughly 100 m before the runway end, the towline unexpectedly released from the glider’s nose hook for undetermined reasons.
5. Attempted turn back: Instead of landing ahead or slightly to the right on available fields, the crew initiated a right turn to attempt a downwind landing back on the airfield, with the instructor allowing or joining this maneuver after a brief wait for student reaction.
6. Low-altitude downwind turn: During the low-altitude turn into downwind over the restaurant terrace, the glider experienced a sudden height loss and drift toward the restaurant and hangar, with airspeed decaying to about 50–60 km/h.
7. Crash - no injury: The instructor attempted to land between the hangar and parked aircraft, the glider contacted the ground at the start of the hangar, slid between the hangar and two parked airplanes, and came to rest against a winch, heavily damaging the glider but leaving both occupants uninjured.