Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.
The trainee, accompanied by an instructor on board the glider registered F-CJBH, as well as the pilot of the glider registered F-CHNP were using the uplifts near Issoire Le Broc aerodrome (Puy de Dôme). Having found a very favourable uplift, the instructor used the radio to invite the pilot of F-CHNP, who was at a lower altitude, to join them. The latter entered the uplift and made spirals to the left. After the second turn, the instructor saw that the paths were converging and made a sudden manoeuvre to the right to exit the turn. The glider paths crossed and the right wing tip of F-CHNP came into contact with the underside of the F-CJBH fuselage. Both pilots observed that the winglet of the F-CHNP’s right wing was missing. The controls of both gliders remained functional and the pilots landed shortly after on runway 36 at Issoire Le Broc aerodrome. On the ground, the instructor on board F-CJBH noticed that the skin of the fuselage level with the cockpit was cut over approximately 10 cm.
When using the uplift, despite the FLARM visual indication, the pilot of F-CHNP did not see that he was catching up with the glider registered F-CJBH that was higher up in the same uplift. This catching up both in the horizontal plane and the vertical plane was probably down to the better flight characteristics of the LAK 19 and a faster flying speed. After approximately two turns, the F-CHNP pilot found himself inside a turn on a path converging with that of F-CJBH. The pilot of F-CHNP became aware of the conflictual situation late and was unable to avoid contact between the two gliders.
The instructor on board F-CJBH, given that F-CHNP arrived from the rear, was unable to detect its presence early enough for the emergency manoeuvre that he performed to prevent the collision.
The lack of vigilance and anticipation by the pilot of F-CHNP led to both gliders being on a converging path and to the midair collision.