What happened
On August 6, 2020, during the National Gliding Competition at Grudziądz – Lisie Kąty (EPGI) airport, a mid-air collision occurred between two gliders at an altitude of approximately 800 m AGL. The aircraft involved were an SZD-48-3 Jantar Std. 3, registration SP-3542, and a Schempp-Hirth Mini-Nimbus C, registration SP-4021.
Both gliders were circling in a shared thermal accompanied by approximately 30 other aircraft. The pilot of the SP-3542 was flying a tight radius, while the pilot of the SP-4021 was flying a wider path. During left-hand turns, the cockpit canopy of the SP-3542 struck the lower fuselage of the SP-4021.
The impact caused significant damage to both aircraft. The SP-3542 suffered a destroyed canopy, structural damage to the wings, and entered an uncontrolled, unrecovered spin. The pilot of the SP-3542 eventually recovered from the rotation at roughly 600–650 m AGL and performed an emergency landing in a field near Bzowo, sustaining one light injury. The pilot of the SP-4021 remained in control and successfully returned to the airfield. The SP-4021 also sustained damage, including a deployed landing gear and fuselage fractures.
The investigation
The PKBWL investigation examined flight logger data, aircraft wreckage, and pilot statements. The investigation focused on the flight trajectories within the thermal, the visibility between the two pilots, and the operational environment of the competition. The analysis of the flight logs revealed that the SP-3542 was flying a much tighter circumference, which allowed it to overtake the SP-4021 on a collision course.
Findings
- The primary cause was inadequate airspace observation and failure to maintain separation by both pilots while circling in the thermal.
- The pilot of the SP-3042 was flying a too-tight circling pattern that intersected the flight path of the other aircraft.
- Contributing factors included the pilots' high level of concentration on calculating glide paths to the destination airport rather than monitoring surrounding traffic.
- The pilot of the SP-3542 had previously been noted for aggressive flying and failing to maintain safe distances from other gliders during the competition.