Ka 4 Rhönlerche II aterrizaje en campo en una gravera cerca del aeródromo de Winterthur
El 5 de julio de 1964, un Ka 4 Rhönlerche II realizó un aterrizaje en campo cerca del aeródromo de Winterthur en Suiza. El vuelo formaba parte de un ejercicio de entrenamiento realizado por el grupo de vuelo a vela de Winterthur. Durante la aproximación de aterrizaje, el piloto estudiante calculó mal la altitud y encontró corrientes descendentes, lo que llevó a un aterrizaje en campo en una gravera cercana. La aeronave sufrió daños en el fuselaje y las conexiones de las alas, pero el piloto resultó ileso. El incidente ocurrió durante el primer uso del aeródromo recién inaugurado por el grupo.
- Winch launch circuit: The student pilot launched by winch from Winterthur-Hegmatten and flew a standard training circuit, reaching about 260 m above the field before positioning for landing.
- Low experience level: The student had limited overall gliding experience and this was only his second flight from the newly opened Winterthur-Hegmatten airfield, reducing his familiarity with its circuit and height cues.
- Low circuit altitude: Before starting the approach he descended in turns to roughly 100 m above the field, which was at the lower limit for executing a normal landing pattern.
- Altitude misjudged: Believing he still had sufficient height, the student turned onto a normal-length final approach similar to the preceding dual check flight, despite being lower than appropriate.
- Downdraft on final: While on final over the water surface of the gravel pit in line with runway 05, the glider encountered sinking air that further reduced its glide path.
- Committed to outlanding: Recognizing he could no longer reach the airfield, the pilot continued just above the water surface, which lay about 4 m below field level, and elected to land in the gravel pit area.
- Outlanding - damage: The glider touched down on a gravel bank and then collided head-on with the edge of the pit, damaging the fuselage nose and wing attachments while the pilot remained uninjured.