Mid-air collision of two K8B gliders near Schupfart airfield results in one fatality

On June 25, 1972, two Alexander Schleicher K 8 B gliders collided mid-air approximately 2.5 km south-southwest of Schupfart airfield in Switzerland. The collision occurred when the pilot of one glider flew into the other from behind. The pilot of the first glider was able to parachute to safety, while the other pilot was fatally injured as his aircraft crashed. The incident resulted in the destruction of one glider and severe damage to the other. Weather conditions were clear, and no technical malfunctions were reported in either aircraft.

1. Thermaling in gaggle: Both K8B gliders HB-906 and HB-738 were thermaling in right-hand circles at similar altitude, laterally offset within the same general lift area near Schupfart.
2. HB-906 turns toward HB-738: The pilot of HB-906 leveled out of his right-hand turn, left his own lift area, and flew directly toward HB-738 from behind and to its left at approximately the same altitude.
3. Inadequate lookout: Investigators considered that the HB-906 pilot may not have seen HB-738, possibly due to sun glare, a blind spot, or insufficient airspace scanning while maneuvering in the thermal.
4. HB-738 evasive turn: Seeing HB-906 flying toward him on a collision course, the HB-738 pilot tightened his right-hand turn as steeply as possible in an attempt to avoid impact.
5. Mid-air collision: HB-906’s canopy area struck the left aileron of HB-738, and subsequent contact between HB-906’s right wing and HB-738’s tailplane caused severe structural damage to both gliders.
6. Bailout from HB-738: After HB-738 entered a flat spin, its pilot opened the canopy, released his harness, and successfully bailed out under parachute, while HB-906’s pilot jettisoned the canopy and opened his belts but did not or could not complete a parachute escape.
7. Crash - fatal: HB-906 entered a descending inverted spiral and crashed into a steep wooded slope fatally injuring its pilot, while HB-738, though heavily damaged, was left without pilot on board after the successful bailout.