Accidente del Ka 6 en Diablerets debido a colisión con pared rocosa en baja visibilidad

El 14 de julio de 1983, un planeador Ka 6 CR pilotado por un ciudadano suizo se estrelló contra la cara noroeste de los Diablerets en Suiza. El piloto participaba en un campamento de vuelo a vela alpino y despegó para un vuelo de larga duración. La aeronave fue reportada como desaparecida cuando no regresó a las 18:00 hora local, lo que provocó una operación de búsqueda. Los restos fueron descubiertos al día siguiente a una altitud entre 2500 y 2900 metros. El piloto sufrió heridas mortales y el planeador fue destruido. La colisión con la pared rocosa ocurrió probablemente cuando el piloto voló hacia las nubes sin la formación necesaria.

1. Aerotow cross-country: The pilot departed Zweisimmen at 11:26 local on an aerotow for a long alpine soaring flight in Ka 6 CR HB-766.
2. Marginal mountain weather: In the Diablerets area the afternoon weather featured a cloud base around 2700–3000 m with partial heavy cloud, rotor cloud and descending cloud fragments, and nearby peaks often in cloud.
3. No cloud-flying rating: The pilot was licensed only for VFR gliding and had no authorization or documented training for cloud (IFR) flight, although the aircraft itself was approved for cloud flying.
4. Entered cloud near terrain: While ridge-soaring near the Diablerets around 16:45, the glider did not avoid descending cloud fragments and very probably entered cloud in close proximity to the northwest rock face.
5. Continued near clouds: Witnesses observed the glider at times in or behind clouds and noted that it did not deviate to avoid cloud fragments, suggesting the pilot continued flight close to or within cloud despite limited visibility.
6. Loss of visual reference: Once in cloud near steep terrain, the pilot likely lost external visual references and, despite the turn coordinator being powered, was not able to maintain safe separation from the mountainside.
7. Crash - fatal: The glider impacted the steep northwest rock face of the Diablerets at about 2900 m, was completely destroyed, and the pilot sustained fatal injuries.