Spin during slope flight leads to forest crash at Wasserngrat for SZD-8ter from Saanen
During a slope flight, the glider HB-629 entered a spin and crashed into a forest of fir trees. The incident occurred on July 11, 1970, in the context of a gliding camp organized by AéCS in Saanen. The probable cause was a low-altitude spin due to a loss of speed, which could not be determined with certainty. The pilot sustained serious injuries, and the glider was destroyed in the impact.
- Slope soaring flight: After aerotow from Saanen and release near Hornberg, the pilot flew slope along the Wasserngrat ridge near the restaurant at roughly 100–200 m above terrain.
- Low height near slope: While flying a wide turn near the ridge and restaurant, the glider was at low altitude over steep, forested terrain, leaving limited height for recovery.
- Turbulent ridge conditions: The area was affected by irregular turbulence and possible rotor or transition effects from a 10–15 kt northwesterly wind over the ridge.
- Sudden loss of airspeed: During a left turn back toward the slope at about 85 km/h, the glider likely experienced a brief loss of relative airspeed, leading to an uncommanded stall.
- Uncommanded spin: The tail suddenly rose and the glider entered a left spin at low altitude, contrary to the pilot’s intentions.
- Insufficient spin recovery: The surprised pilot pushed the stick forward in an attempt to stop the spin, but with only about 200 m of height available there was not enough altitude for the several turns needed for full recovery.
- Crash - serious injury: Still in a developed descent, the glider struck the tops of tall fir trees and crashed down through the forest, destroying the aircraft and seriously injuring the pilot.