ASW 19 spins into a ridge after sinking low on the lee side

An ASW 19 B ridge-soaring the Scex Rouge struck the rock face about 50 m below the crest and was destroyed, killing the pilot. In a 15-20 kt west wind he worked both sides of the ridge, but the lee (east) slope sank as hard as the windward side lifted. He was seen flying lower and deeper into the combe, where the sink ran close to terrain and cable-car wires crossed the slope. Caught by the sink and turning hard left to clear the cables, the glider snapped into a very tight turn — more probably a spin — and after about 1½ rotations hit the face. The investigation blamed inappropriate tactics on a lee slope exposed to strong sink.

1. Aerotow ridge flight: The pilot aerotowed from Bex around 1448 for a local training flight and later flew ridge-soaring along the Scex Rouge in the Diablerets area.
2. Leeward downdraft area: The pilot repeatedly flew through the east slope and Dar combe on the leeward side of Scex Rouge, an area known to generate strong downdrafts and turbulence in westerly winds.
3. Low, deep in combe: At about 1600 the glider was observed flying lower and deeper into the Dar combe on the east side of Scex Rouge, exposing it to strong sink close to terrain and cable car wires.
4. Abrupt left turn: In attempting to turn left away from the east slope and avoid the cable car cables, the pilot initiated a very tight left turn at low height near the ridge.
5. Develops steep turn/spin: The glider entered a very steep left bank and likely an incipient or fully developed spin, completing about one and a half turns while descending toward the slope.
6. Crash - fatal: After roughly one and a half turns the glider struck the east rock face of Scex Rouge about 50 m below the ridge, destroying the aircraft and killing the pilot instantly.