Ka 6 CR and ASK 13 cross paths in shared thermal

In a shared-thermal mid-air, the pilot of a Ka 6 CR was fatally injured and an ASK 13 student (~20 h) bailed out safely; both aircraft destroyed. After visual loss, the Ka 6 CR's left wingtip struck the ASK 13's right wing; the Ka 6 CR lost its left outer wing (~2.5 m), spiral-dove into a garden; the pilot's bailout came too low. Both winch-launched from Steinberg-Wesseln; the ASK 13 circled left S of the field, the Ka 6 CR joined below, worked the lift better, reached its altitude. At ~600 m AGL visual was lost; the student assumed the Ka 6 had left. No technical defects. Cause: paths crossed at same altitude; recognised too late.

1. Two gliders thermalling near airfield: Winch launches from Steinberg-Wesseln on a VFR afternoon: the Ka 6 CR launched first, releasing north of the field; the ASK 13, flown solo by a student, launched 10 min later nearby.
2. Ka 6 CR joins ASK 13 thermal below: The ASK 13 student found lift south of the airfield and started left-turning circles; the Ka 6 CR pilot saw the ASK 13 climbing and joined the same thermal below it, also circling left.
3. Ka 6 CR climbs to ASK 13 altitude: Ka 6 CR worked the lift better than the ASK 13 and reached the same altitude. Up to then both pilots had good visual contact with each other.
4. Both lost visual at ~600 m AGL: At about 600 m AGL both pilots lost sight of each other; the Ka 6 CR pilot likely displaced his circle to overclimb the ASK 13, whose student assumed the Ka 6 CR had left the thermal.
5. Ka 6 wingtip strikes ASK 13; Ka 6 dives: The Ka 6 CR's left wingtip struck the ASK 13's right wing after both displaced their circles; the Ka 6 CR lost its wing and spiralled down, killing the pilot, who bailed out too low.