DG-1000 stalls in a steep turn while slope-soaring a ridge

A pilot and passenger were killed and the glider destroyed when it stalled in a turn while slope-soaring and struck a wooded mountainside. After an aerotow release near the ridge at about 1200 m, the glider flew a spiral and then alternating figure-eight turns along the slope at more than 30 degrees of bank. Over the final seconds its speed fell from about 110 to 80 km/h, close to the stalling speed. In a right turn the glider departed controlled flight, and the low soaring height left no room to recover before it hit the trees on a steep slope. An examination found no defect; airbrakes, gear and motor were retracted and both canopies locked.

1. Slope-soaring the Rochers de Hongrie: After an aerotow release near the ridge at about 1200 m, the glider flew a spiral and then alternating figure-eight turns along the slope.
2. Speed decays in the turns: Flying the figure-eights at more than 30 degrees of bank, the glider's ground speed fell from about 110 to 80 km/h over the final seconds.
3. Close to the stall speed: The wings-level stall speed was about 74 km/h and rises with bank, so the decaying speed brought the glider close to stalling in the turns.
4. Loss of control in a right turn: In a right turn the glider departed controlled flight while banked steeply along the slope.
5. No height to recover: The low slope-soaring height gave the pilot no room to regain control before reaching the ground.
6. Struck the wooded slope: The glider hit trees on a steep wooded slope on a near-vertical path; both occupants were killed and the glider destroyed.