What happened
On August 5, 2021, during the second day of official preparatory training for the World Gliding Championships at Montluçon Guéret, a mid-air collision occurred between two gliders. The incident involved a ROLLADEN SCHNEIDER LS8-18, registered D-4776, and a SCHEMPP HIRTH Ventus 1A, registered D-5063.
At approximately 14:19, the pilot of D-5063 was attempting to join a group of gliders performing right-hand spirals within an uplift. While using another glider as a visual reference point, the pilot of D-5/063 struck the D-4776 glider. The collision caused minor damage to both aircraft, including damage to the trailing edges and wing tips of D-4776 and damage to the horizontal tailplane of D-5063. Following the impact, the pilot of D-5063 declared a Mayday and performed an emergency landing at the aerodrome, while the pilot of D-4776 landed safely shortly thereafter.
The investigation
The BEA examined data from onboard IGC computers and video footage from a third glider to reconstruct the flight paths. The investigation established that both aircraft were traveling at ground speeds of approximately 116 km/h at the moment of impact. The investigators also reviewed the meteorological conditions, noting that the convective air mass and temperature inversion present that day were not ideal for gliding competition.
Findings
- The pilot of D-4776 did not perceive the incoming aircraft because it approached from behind.
- The pilot of D-5063 failed to detect D-4776 because they were focused on a different glider used as a visual reference for joining the group.
- The high density of aircraft in the same airspace significantly hindered the effectiveness of the FLARM collision avoidance system, as the large number of nearby gliders caused continuous aural warnings and cluttered the display.
- The competition organization had assigned the same flight route to all glider classes for this training session, leading to a high concentration of aircraft in the same area.
- While takeoff sequences were properly managed, many pilots waited near the start line to utilize available uplifts, increasing the risk of proximity-related incidents.