LAK-19 spins off the left wing after sinking in ridge turbulence

A LAK-19 on a ridge-soaring flight spun into steep forest and the pilot was killed. The day was a south-Föhn situation with a strong westerly along the crest and turbulence that another pilot said had to be flown with extra speed. Almost two hours after release the glider was seen to sink sharply at 1700 to 1800 m, roll over the left wing at 50 to 100 m above the ground and spin into a wooded slope. The recorded cause was a loss of control in flight, with low height, too little speed margin and an out-of-date flight manual named as factors: it gave the stall speed as 75 km/h, the current revision 82 km/h.

1. Aerotow along the Hochanger ridge: The glider was towed north along the ridge in light southerly wind at the airfield, with lee turbulence in places and a marked westerly higher up.
2. Release 1000 m above the airfield: The tow ended about 1000 m above airfield level, west of the ridge and roughly midway between the later accident site and the northern end.
3. Slope soaring in a Föhn westerly: Thermals were absent or broken, but the west faces looked soarable. A pilot who launched later found turbulence that needed extra speed.
4. Glider sinks sharply: Almost two hours after release, at 1700 to 1800 m, another pilot 300 to 400 m behind saw the glider sink strongly. Turbulence-driven downdraught fits the description.
5. Left wing drops into a spin: At 50 to 100 m above the ground the glider rolled over the left wing and began to spin.
6. Impact on a 40-degree slope: It struck trackless forest on a 40-degree slope. The cockpit damage and destroyed right wing indicate a steep impact with right bank.