Accidente del Discus b en la cresta de Mattstock debido a pérdida de sustentación en condiciones turbulentas
El 13 de junio de 1987, un planeador Schempp-Hirth Discus b se estrelló en la ladera noroeste del Mattstock, en Amden, Suiza. El piloto despegó del aeródromo de Schänis para un vuelo local en condiciones de foehn. Después de soltar el remolque a 2200 metros, el piloto intentó encontrar ascensos pero encontró turbulencias. Al aproximarse a la cresta desde el oeste, el planeador entró en pérdida y giró, impactando la ladera a 1820 metros. El piloto resultó fatalmente herido y el planeador fue destruido. La investigación confirmó tácticas de vuelo inadecuadas y una pérdida de sustentación cerca de la ladera como causas.
- Aerotow local flight: The pilot took off by aerotow from Schänis airfield at 10:47 for a local foehn soaring flight.
- Release in weak lift: The pilot released the tow at 2200 m above Mattstock in relatively weak foehn and turbulence, then was unable to find usable lift.
- Slow flight near ridge: While losing about 300 m in 14 minutes, the pilot likely flew at best glide or too low an airspeed for the wind conditions as he approached the Mattstock ridge from the west.
- Aft CG condition: The glider was within limits but had an extremely aft center of gravity, reducing stall and spin margins.
- Stall near ridge: Approximately 100 m above the Mattstock crest, in the lee/lift transition area and at too low an airspeed, the glider stalled.
- Spin and descent: Following the stall the glider entered a spin to the right, and the low height above terrain was insufficient for recovery.
- Crash - fatal: Still in a right-hand rotation, the glider impacted almost perpendicularly into the northwest slope of Mattstock at about 1820 m, destroying the aircraft and fatally injuring the pilot.