Discus b crash on Mattstock ridge due to stall in turbulent conditions
On June 13, 1987, a Schempp-Hirth Discus b glider crashed on the northwest slope of Mattstock, Amden, Switzerland. The pilot launched from Schänis Airfield for a local flight in foehn conditions. After releasing the tow at 2200 meters, the pilot attempted to find lift but encountered turbulence. Approaching the ridge from the west, the glider stalled and spun, impacting the slope at 1820 meters. The pilot was fatally injured, and the glider was destroyed. The investigation confirmed inadequate flight tactics and a stall near the slope as causes.
- 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.