Ventus CT stalls in winch climb: steep attitude held at low tow speed

The pilot of a Ventus CT was fatally injured when the glider stalled in the initial winch climb at ~30 m AGL, rolled off the left wing and struck the airfield ~316 m from the threshold; destroyed. The pilot — 748 h total, 25 launches on type — was on his second winch launch of the day; the first ~80 min earlier was uneventful. After liftoff witnesses observed the winch tow speed as noticeably low; the pilot held the steep climb attitude without reducing it. The Ventus exceeded its critical angle of attack, stalled and rolled off too low to recover. Heat shimmer (~34 °C ambient) may have impaired the winch operator's view. No technical faults.

1. Second winch launch of day, RWY 07: Pilot's second winch launch of the day on RWY 07 at Lüsse; the first ~80 min earlier was uneventful. About 748 h total / 25 launches / 11 h on type.
2. Hot day; heat shimmer over runway: Ambient ~34 °C; heat shimmer at ground level may have impaired the winch operator's view of the glider — couldn't be excluded.
3. Winch tow speed noticeably low: Witnesses observed the winch tow speed as noticeably low during the initial climb, reducing the margin above stall speed.
4. Climb attitude too steep for tow speed: The pilot established and held a climb attitude too steep for the available winch tow speed; the attitude was not reduced.
5. Stall and wing drop at ~30 m AGL: At about 30 m AGL the Ventus exceeded its critical angle of attack, stalled and rolled off over the left wing; insufficient height for recovery.
6. Nose-down impact 316 m from threshold: The Ventus impacted at high nose-down pitch and slight inverted attitude ~316 m from the runway threshold, ~50 m left of centerline; the pilot was fatally injured and the airframe destroyed.