What happened
On June 19, 1999, at approximately 16:10, two gliders were involved in a mid-air collision near Châtloillon-sur-Morin, France. The flight began around 11:30 when three gliders departed from Coulommiers for a planned 500-kilometer circuit, later joined by a fourth aircraft. Due to weather conditions being less favorable than anticipated, the group of four pilots decided to shorten their route.
During the return leg of the flight, the pilots attempted to climb to 1,400 meters to facilitate their return to Coulommiers. A witness pilot observed the Rolladen Schneider LS 4 (registration F-CFZG) performing a right-hand spiral dive. As the pilot of the F-CFZG leveled the aircraft, its flight path converged with that of a DG Flugzeugbau DG 600 (registration F-CGRO) approaching from the left. The collision occurred when the underside of the left wing of the F-CFZG struck the upper surface of the right wing of the F-CGRO.
Following the impact, the pilot of the F-CFZG exited the aircraft by opening the canopy without jettisoning it and successfully deployed a parachute. The pilot of the F-CGRO attempted to egress the aircraft, but the parachute lines became entangled in the fuselage, resulting in a fatal outcome for the pilot of the F-CGRO. Both aircraft were destroyed in the accident.
The investigation
The investigation focused on the flight dynamics leading to the convergence of the two aircraft and the physiological state of the pilots. Investigators examined the flight duration, the group formation, and the meteorological conditions present during the mission. The investigation also reviewed the radio communications, noting that all four aircraft in the group were operating on the same frequency.