What happened
On August 10, 1960, at approximately 13:20, two gliders were performing alpine soaring flights near the Schafberg mountain, specifically near the Segantini Hut, when they collided head-on. The aircraft involved were a Bergfalke II (registration HB-529) and a Ka 2b (registration HB-606).
The HB-529 was being flown solo. During the flight, the pilot experienced sudden illness, which briefly diverted his course before he resumed a southeast heading toward the Schafberg. Simultaneously, the HB-606, carrying two pilots, was flying toward the same area. The two aircraft were traveling on nearly opposite courses at an altitude of approximately 2,800 meters.
At the moment of impact, the pilots had very little time to react. The crew of the HB-606 spotted the other aircraft only about 50 meters away, leaving less than one second for an effective evasive maneuver. The collision caused significant structural damage to both gliders: the HB-606 lost a large section of its left wing, and the HB-529 lost its vertical stabilizer and rudder.
Following the impact, the pilot of the HB-529 was forced to bail out via parachute after the aircraft became uncontrollable. The HB-606 managed to return to Samedan airfield, but the aircraft broke up during its landing attempt. There were no fatalities, though the pilot of the HB-529 sustained a minor foot injury.
The investigation
The investigation examined the flight paths, weather conditions, and the visual circumstances leading to the collision. Investigators analyzed the aircraft's structural damage, the pilots' flight experience, and the visibility conditions at the time of the accident. The inquiry also considered the impact of the aircraft's color schemes and the physiological state of the pilot of the HB-5ly.
Findings
- The primary cause of the collision was insufficient airspace surveillance by both crews.
- Visual detection was significantly hindered by low color contrast; the white HB-529 was flying against a milky gray cloud layer, while the yellow HB-606 was set against a rocky mountain background.
- The aircraft were flying in a straight line, presenting minimal surface area for detection.
- The pilot of the HB-529 may have had reduced situational awareness due to recent physical illness.
- The single-seat configuration of the HB-529 may have reduced the likelihood of spotting the other aircraft compared to a multi-person crew.