What happened
On July 29, 2016, at approximately 13:20 local time, a Sportine Aviacija LAK-17A glider, registration F-CHNX, was engaged in a general aviation flight departing from the Romans - Saint-Paul aerodrome. After being towed to an altitude of 1,518 meters near the Bouchère ridge, the pilot released the tow cable and proceeded toward the Tête de la Dame mountain, following the ridgeline.
While flying at an altitude of approximately 1,450 meters, the pilot attempted to navigate around the mountain by heading south and then east, passing beneath the ridgeline. During this maneuver, the glider encountered downdrafts. In an attempt to move away from the terrain, the pilot initiated a right-hand turn, but the aircraft subsequently struck the treetops and collided with the ground. The aircraft was destroyed in the impact.
The investigation
The investigation focused on the meteorological conditions and the pilot's flight path. The pilot, who held a glider pilot license since 2009 and had 606 total flight hours, had attended a morning briefing where weather was reported as CAVOK with a 3-knot northern wind. However, regional meteorological records at the time of the accident indicated a more significant northern wind of 5 to 10 knots, with gusts reaching 10 to 15 knots over the terrain.
Findings
- The pilot had encountered a small thermal earlier in the flight but chose to bypass it, hoping for better conditions south of the relief.
- The reported northern wind direction was conducive to creating downdrafts on the leeward side of the slopes.
- The pilot's decision to fly on the leeward side of the terrain was likely influenced by the low wind speeds reported during the morning briefing.
- The proximity to the terrain prevented the pilot from executing a sufficient recovery maneuver to avoid the trees on the slope.