Colisión en el aire entre Speed Astir II y Ka 6 sobre Piz Tschierva, Suiza
El 12 de agosto de 1982, ocurrió una colisión en el aire entre un Grob Speed Astir II y un Alexander Schleicher Ka 6 CR sobre el Piz Tschierva, Suiza. El Speed Astir II, pilotado por un ciudadano alemán, colisionó por detrás con el Ka 6 CR a una altitud de 3.807 metros. El Speed Astir II perdió una parte de su ala y se estrelló contra la montaña, resultando en la muerte del piloto. El Ka 6 CR sufrió daños menores pero pudo regresar de manera segura al aeropuerto de Samedan. No se reportaron lesiones para el piloto del Ka 6 CR, y no hubo daños a terceros.
- Winch launch and climb: The Speed Astir II D-2904 launched by winch from Samedan at 14:27 and proceeded to soar in the local alpine area.
- Crowded thermal area: Around Piz Tschierva there were about 15–20 gliders using the same lift, flying mixed turning directions and figure‑eight patterns at varying altitudes.
- High-speed arrival: Shortly before 16:02 the Speed Astir approached the Piz Tschierva lift area at relatively high speed from outside the main gaggle, descending toward the group of gliders.
- Target glider not seen: While entering the dense group of gliders, the Speed Astir pilot did not see the Ka 6 CR HB-836 ahead in his flight path.
- Rear-quarter impact: At 16:02 the Speed Astir, banked about 55–60° right and on a roughly 325° track, struck the Ka 6 CR from behind and left at 3,807 m, with high relative speed.
- Wing loss and spiral: The collision severed a 3.27 m outer section of the Speed Astir’s right wing, causing the glider to flip longitudinally over the Ka 6 and enter an uncontrollable spiral dive toward terrain.
- Crash - fatal: The Speed Astir impacted the west face of Piz Tschierva around 3,400 m and was destroyed, fatally injuring the pilot, while the Ka 6 CR remained controllable and later landed safely at Samedan.