Schleicher K 10A crash on Alp Wildeneggli during turbulent ridge flight
On August 6, 1999, a Schleicher K 10A crashed on Alp Wildeneggli in Switzerland during a ridge flight. The pilot, who had taken off from Saanen airfield, encountered turbulent conditions influenced by Föhn winds. While attempting to gain altitude, the aircraft stalled and entered a steep dive, leading to a collision with the terrain. The pilot was fatally injured in the impact. The investigation found no technical defects in the aircraft, and the pilot was not impaired by alcohol or health issues.
- Aerotow cross-country: The pilot aerotowed from Saanen at 1410 for a private cross-country soaring flight in thermic conditions influenced by Föhn.
- Broken Föhn thermals: Due to Föhn influence in the Berner Oberland, the thermals were broken and the area around the later accident site was affected by lee turbulence.
- Low ridge height: After about two hours of flight the pilot arrived relatively low near Alp Wildeneggli and attempted to gain height along the slope.
- Stall in turbulence: While trying to climb in ridge lift on the lee side in turbulent conditions, the glider’s speed dropped below minimum and the wing stalled.
- Steep dive to ground: Following the stall, the glider entered a steep, high-speed descent toward the sloping terrain, with no effective recovery before impact.
- Crash - fatal: The glider impacted the 45-degree alpine slope at high speed, was destroyed, and the pilot sustained fatal injuries.