Colisión del Ka 4 Rhönlerche II durante un aterrizaje en campo de entrenamiento en el aeródromo de Winterthur
El 24 de mayo de 1969, un Ka 4 Rhönlerche II estuvo involucrado en un incidente en el aeródromo de Winterthur, Suiza. Durante un vuelo de entrenamiento, el instructor y el piloto estudiante se vieron obligados a realizar un aterrizaje en campo debido a la baja altitud. La aeronave colisionó con una máquina agrícola estacionaria al aterrizar. Ambos pilotos resultaron ilesos, pero el planeador sufrió daños significativos. El informe oficial atribuye el incidente a un error de juicio del instructor durante la aproximación de aterrizaje.
- 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.