Ka 4 Rhönlerche II collision during training outlanding at Winterthur airfield
On May 24, 1969, a Ka 4 Rhönlerche II was involved in an incident at Winterthur airfield, Switzerland. During a training flight, the instructor and student pilot were forced to perform an outlanding due to low altitude. The aircraft collided with a stationary agricultural machine upon landing. Both pilots were unharmed, but the glider sustained significant damage. The official report attributes the incident to a misjudgment by the instructor during the landing approach.
- Aerotow training flight: Instructor and student departed Winterthur on an aerotow in a Rhönlerche II for an instructional flight and released at about 500 m AGL near Wiesendangen.
- Weak unusable thermals: After release the instructor attempted to use weak thermals near Wiesendangen but was unable to gain or maintain sufficient altitude.
- Low height on return: The instructor instructed the student to return to the airfield at about 300 m AGL, and the circuit was flown down to roughly 120 m AGL, leaving limited height margin.
- Too low for airfield: During the student’s turn onto base leg at about 30 m AGL with a strong headwind and a 4 m gravel heap on the approach path, the instructor recognized that the airfield could no longer be reached safely.
- Decision to outland: The instructor decided to perform an outlanding in the field below and executed a strong right sideslip to lose height and align for landing.
- Obstacle not avoided: Wind drift during the right sideslip and reduced field visibility from the rear seat contributed to the glider’s path bringing the left wing close to a stationary hay tedder near the field edge.
- Outlanding - damage: After a normal touchdown and 2–3 m of ground roll in the field west of the airfield, the left wing struck the parked agricultural machine, heavily damaging the glider but leaving both pilots uninjured.