JS1 stalls and spins on a third flight on type in turbulent thermals

The pilot of a Jonker JS1 was lightly injured and the glider heavily damaged when it stalled and spun near Mont Crosin on only his third flight on the demanding type. He had about 104 hours in total and 2:42 on the JS1, all from the day before, and the thermals were turbulent with the centre of gravity near its aft limit. Hunting for lift, his airspeed bled from 117 to 84 km/h in ten seconds as the glider rose; it stalled and spun at 250 m. He began to recover but ran out of height before striking a stand of young trees.

1. 3rd type-familiarization flight: After aerotow release near Mont Crosin, the pilot searched for thermals without success on her third familiarization flight on the high-performance JS1-C single-seater with a jet sustainer.
2. Low total experience: The pilot had accumulated only 2:42 h on the JS1-C, entirely on the previous day, with limited total flight experience overall.
3. Demanding type, CG near aft limit: The JS1-C is a high-performance single-seater with flaps and a small jet sustainer; its centre of gravity was within limits but close to the aft limit, which worsens stall behavior.
4. Turbulent thermals: Wind gusted to 25 kt, and the forecast for the Jura indicated turbulence with broken, moderate thermals — conditions demanding for a low-experience pilot.
5. Training setup overwhelmed pilot: Low total experience, limited time on comparable demanding types, and turbulent conditions caused a capacity overload; the accompanying pilot was competent but not instructor-qualified.
6. Inadvertent zoom and energy bleed: From 12:41:03, IAS dropped from 117 to 84 km/h in 10 seconds while altitude rose — the JS1-C zoomed and bled energy. Variometer was showing 3-4 m/s sink before the stall, per the pilot.
7. Stall and spin entry at 250 m AGL: The glider stalled and entered a spin at about 250 m above ground while airspeed continued to decay; the aft centre of gravity, though within limits, contributed to the stall and spin.
8. Recovery short of height: The pilot attempted spin recovery but could not complete it before ground impact after more than one turn; the emergency parachute was not deployed.
9. Young-forest impact: The JS1-C struck a young-forest area; the left wing detached, and the right wing and cockpit were badly damaged. The pilot self-extracted with light injuries.