LS 1-0 ridge collision during alpine flight; speed below ridge minimum

The pilot of an LS 1-0 was fatally injured in a collision with terrain north of the Klausenpass (Switzerland) during an alpine cross-country. The glider had launched at 11:31 from Schänis by aerotow and flown via the Engadin to Piz Linard before turning back. After about 4 h 51 min the pilot was following the rock faces of Jegerstöck and Glatten at a near-constant altitude of ~2,400 m MSL with a ground speed of only 73 to 82 km/h — well below the 87-94 km/h IAS recommended for ridge flying close to terrain. The glider struck the slope, tumbled ~300 m down the face, and was discovered 46 days later.

1. Aerotow Schänis + alpine XC: The LS 1-0 launches on aerotow from Schänis, releases at ~2,600 m, climbs past 4,000 m in wave over the Calfeisental, reaches Piz Linard, then returns via Bad Ragaz into the Glarnerland.
2. Low-speed ridge flying at ~2,400 m: On the return leg the pilot crosses south of Linthal toward the Ortstock, then follows the rock faces of Jegerstöck and Glatten for about five minutes near ~2,400 m MSL, close to the ridge.
3. Ground speed below ridge minimum: In the final 20 seconds ground speed was only 73-82 km/h, below the recommended minimum of 87-94 km/h IAS for flying this close to terrain. A moderate Föhn added a crosswind.
4. Terrain contact; 300 m fall on cliff: The glider first hit the ridge face north of the Klausenpass at about 2,425 m, then fell over the cliffs, breaking apart across a ~300 m band of rock. The pilot was fatally injured.
5. No technical defect; 46-day search: Examination excluded a technical cause: no abnormal accelerations, no parts shed in flight, mass and CG within limits. No locator signal was received; wreckage was found 46 days later.