Ka 8 B and UL collide on simultaneous approaches to parallel runways

A Ka 8 B and a Z 602 XL ultralight collided on final to RWY 24 at Koblenz-Winningen; all three occupants were lightly injured and the wrecks fell into an orchard. Both approached the parallel asphalt and grass runways though the AIP forbade simultaneous approaches. The Ka 8 B, on a winch training flight, was higher than usual on downwind for side-slips, using only the brief local 'Position' call. As the glider entered a left slip at about 150 m, the UL — turning to final in a 30-45 degree bank — struck it from above-right and the wrecks interlocked at roughly 90 degrees. The Ka 8 B carried a collision-warning device; the UL did not.

1. Mixed circuit, motor + glider: The airfield ran mixed motor and glider circuits to parallel asphalt and grass runways, with the Ka 8 B on a training circuit and the UL inbound on its motor circuit.
2. AIP forbids simul. approaches: Simultaneous approaches to the asphalt and parallel grass runway were not permitted because lateral separation was too small, yet both aircraft were approaching RWY 24.
3. Comms gap, no glider info to UL: The controller did not tell the inbound UL pilot that glider operations were under way, and the glider pilot's brief radio call did not give arriving traffic a clear picture.
4. Glider higher for side-slip practice: To gain height for side-slip practice, the glider pilot extended the downwind beyond the charted circuit, into airspace where an inbound motor pilot would not expect a glider.
5. Glider on left slip, UL on left turn: The Ka 8 B was in a left side-slip at about 150 m with full airbrakes when the UL turned onto final in a 30-45° bank; neither pilot saw the other before the collision.
6. UL strikes glider from above-right: The UL struck the Ka 8 B from above right; its nose-gear became wedged in the glider's fuselage tubing, locking the two aircraft together at roughly 90°.
7. Interlock, fall to orchard: Interlocked, both aircraft descended into an orchard near the airfield; both were destroyed, and the occupants of both aircraft were lightly injured.