ASK 21 and a CTSW ultralight collide on final approach

Two aboard a Flight Design CTSW ultralight were killed when it collided on final with an ASK 21 glider near Großrückerswalde; the glider landed safely, its occupants unhurt. The glider, just done with an aerobatic display, was turning onto final from above as the ultralight converged from below. Neither pilot could see the other, and a busy flight director noticed them closing too late. The ultralight passed beneath the glider, its fin struck the right wing, and the impact stalled it too low to recover. Investigators cited the absence of mutual visual contact, weak radio coordination, and the glider pilot's restricted rear-seat view.

1. Airshow: glider display + ultralight: At an airshow, an ASK 21 was finishing an aerobatic display while a Flight Design CTSW ultralight, cleared separately, was on a sightseeing flight; both headed for the field.
2. Glider inverted, flown from rear seat: After the aerobatic box the glider was flown inverted back to the circuit and from the rear seat, both limiting the pilot's lookout.
3. Both on final, neither in sight: On final the glider was higher and the ultralight lower and behind; from their positions neither pilot could see the other.
4. Radio call missed by busy director: The glider's radio position call was not taken in by the flight director, who was simultaneously handling a departing ultralight.
5. Ultralight's fin strikes glider wing: The ultralight, overtaking from below, passed under the glider and the top of its fin struck the trailing edge of the glider's right wing.
6. Ultralight stalls and dives; two killed: The impact stalled the ultralight; it pitched over and dived almost vertically, too low to recover or fire its parachute, killing both aboard. The glider landed, its occupants unhurt.