What happened
On 14 June 2017, a Grob G1im03 Twin Astir, registration EC-EPU, was conducting a gliding training flight over the Pyrenees. The flight originated from Jaca, Spain, with an instructor and a student pilot on board. After approximately two hours of flight, the crew reached the vicinity of Mont-Perdu. Seeking to utilize potential thermal uplifts, the instructor decided to cross the border ridge into French airspace. However, instead of finding lift, the aircraft encountered significant downdrafts on the lee side of the terrain.
As the glider lost altitude, the crew searched for thermals or slope lift for nearly an hour but were unable to find suitable conditions. Due to the steep terrain and an overcast valley to the north that prevented access to more open sectors, the crew prepared for an off-field landing near the village of Gèdre. At an altitude of approximately 250 meters, the instructor transferred control to the student pilot. During the downwind leg of the landing approach, the student pilot identified an obstacle and initiated a steep turn to reach an alternative landing surface. This maneuver resulted in a stall at low altitude, causing the glider to strike trees and a power line before impacting a meadow with a gradient exceeding 30%.
The investigation
The investigation focused on the meteorological conditions, the flight path decisions, and the final maneuvers of the aircraft. Investigators examined the wreckage in the meadow, noting that while the wings were broken and folded, the airframe showed relatively little damage and no mechanical malfunctions were identified. Meteorological analysis confirmed an anti-cyclonic pattern with hot, unstable air, which created turbulence and downdrafts on the lee side of the mountains. The investigation also reviewed the crew's decision-making regarding the choice of flight path and the risks associated with crossing the border ridge.