What happened
On October 10, 2009, at approximately 15:20 local time, two Centrair Pégase gliders, registered F-CGFO and F-CHES, were participating in ridge soaring maneuvers near the Pujaut aerodrome. The flight involved four pilots operating in the same area to take advantage of dynamic lift over a nearby low-altitude ridge. All pilots were communicating on the aerodrome's self-announcement frequency.
While flying along a north-east/south-west axis, the pilot of F-CHES performed a 180-degree turn at an altitude of roughly 450 meters, announcing the maneuver via radio. Upon exiting the turn, the pilot observed F-CGFO approaching from the front right at the same altitude. The pilot of F-CHES initiated an avoidance maneuver to the left. During this maneuver, a collision occurred between the two aircraft. Witnesses observed the F-CGFO enter a right-hand spin, completing three full rotations before impacting the ground. The collision resulted in one fatality and the total destruction of the F-CGFO aircraft.
The investigation
The investigation focused on the physical evidence from both aircraft and the operational procedures of the flying club. Examination of the wreckage of F-CGFO revealed impact damage to the underside aileron linkage of the left wing, which likely caused the aileron to jam. The F-CHES aircraft sustained damage to the upper surface of its right wing.
Investigators reviewed the club's safety protocols, noting that the pilots had participated in a pre-flight briefing and that the ridge soaring practice was a standard procedure. The club's internal rules limited such maneuvers to a maximum of four gliders and required a "see and be seen" approach with radio announcements. The investigation also confirmed that the radio equipment on F-CGFO was functional and that the frequency was being monitored on the ground by an instructor.
Findings
- The pilot of F-CHES followed established club procedures by announcing the turn over the common frequency.
- The pilot of F-CGFO attempted an avoidance maneuver to the right, while the pilot of F-CHES maneuvered to the left.
- A lack of vigilance by the pilot of F-CGFO was identified as the probable cause of the collision.
- The absence of FLARM (airborne collision avoidance system) on both aircraft was a significant contributing factor, as the equipment had been ordered but not yet installed at the time of the accident.