What happened
On August 7, 2010, at approximately 12:54 PM, a mid-air collision occurred 2.2 km northwest of Münster airfield in Switzerland. The incident involved an Orlican A.S. Discus CS glider, registration HB-3ability3162, and an Advance Sigma 7 paraglider.
The paraglider pilot had launched from Fiescheralp earlier that morning, gaining altitude through thermals. Meanwhile, the glider pilot was performing figure-eight maneuvers at a relatively constant altitude near the Galmihornhütte. During the flight, the glider overtook the paraglider on its left side, traveling at roughly three times the speed of the paraglider. As the glider executed a right-hand turn away from the slope and toward the paraglider's path, the right wing of the HB-3162 struck the lines of the paraglider.
The impact caused the paraglider canopy to partially collapse and the glider to enter a rapid descent. The glider pilot remained in the cockpit but the impact with the ground was fatal. The paraglider pilot survived the initial impact but died later due to positional asphyxiation.
The investigation
Investigators analyzed data from the glider's "Flarm" collision warning system and the paraglider pilot's GPS unit. Eyewitness accounts from hikers confirmed the high volume of air traffic in the area, noting several gliders and paragliders present at the time. The investigation established that the collision occurred at an altitude of approximately 140 meters above the terrain. Analysis of the flight paths showed that the glider's right wing struck the paraglider's lines, and no other aircraft were maneuvering in a way that would have served as an avoidance maneuver for the glider pilot.
Findings
- The primary cause of the accident was the glider pilot performing a turn toward the paraglider after having likely lost visual contact with it.
- High traffic density in the area required intense situational awareness from both pilots.
- The collision resulted in the destruction of the HB-3162 and significant damage to the paraglider canopy.
Safety action
- The investigation identified a safety deficit regarding the lack of collision warning technology on the paraglider.
- A safety recommendation was issued for the Federal Office of Civil Aviation (FOCA) to work with the Swiss Hang Gliding and Paragliding Association to promote the use of collision warning devices among paraglider pilots.