LS 4 clips treetops on a ridge crest while slope soaring

The pilot of an LS 4 was injured and the glider destroyed when a wing clipped treetops on a ridge crest during slope soaring. A student pilot flying solo launched by winch in weak conditions and, after thermals, ridge-soared the west flank of a Bauges ridgeline in a north-west wind. Tracking the crest south, he flew over it at very low height; just after passing a col the wing caught the treetops near a summit. Destabilised, the glider went into the trees and the forest floor. Investigators linked it to insufficient drift correction along the slope, which took him over the crest too low.

1. Slope soaring the ridge: After a winch launch and some thermals, the pilot ridge-soared the west flank of a Bauges ridgeline in a north-west wind.
2. Low over the crest in weak lift: In weak stable conditions he tracked the crest at low height, close to the terrain.
3. Wing clips the treetops: Insufficient drift correction took him over the crest very low; just after a col the wing caught the treetops near a summit.
4. Destabilised into the trees: The wing-strike destabilised the glider, which collided with the trees and then the forest floor.
5. Wreck in the forest: Both wings and the fin were torn off and the glider destroyed; the pilot was injured but reached help himself.