Serious incident between the Diamond DA42 registered F-HCTA and the Rolladen Schneider LS8 registered HB-3284 on 27/07/2016 at Pont-sur-Yonne (Yonne)

Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.

In descent to Melun-Villaroche aerodrome in IFR flight, in a class E airspace, the passenger seated in the front right seat of the aeroplane detected a glider at the same altitude and on a conflicting flight path. The glider pilot had not switched on his transponder in order to limit the glider’s power consumption. The detection of traffic by the glider’s FLARM therefore relied solely on the use of information from other FLARM. The glider pilot was not in radio contact with the approach controller and had no obligation to be. The approach controller was therefore unaware of the presence of a glider in the area and was unable to provide early traffic information to the aeroplane pilot. The TAS system installed on the DA42 could not provide information to the pilot regarding the glider’s position since the glider’s transponder was not switched on. The DA42 pilot’s evasive action relied solely on the “see and avoid” concept despite the presence on board both aircraft of systems designed to facilitate aircraft detection and avoidance. The glider pilot did not see the aeroplane at any time.