History of the Flight
The student-pilot, accompanied by an instructor, took off at 18:27 from Annecy-Meythet aerodrome (Haute-Savoie). After two aerodrome circuits, including one at low height, the instructor announced their intention to head towards Chambéry - Challes-les-Eaux aerodrome (Savoie) passing via ALBY and to return approximately 45 minutes later.
A security camera at Chambéry recorded the landing on runway 32 at 18:56. Two minutes later, the camera recorded the aeroplane taxiing to runway 32, followed by a take-off at 19:00.
Shortly after 19:00, a witness near Saint-Jean-d’Arvey saw an aeroplane heading towards Col des Prés pass. The witness observed a full left turn in the vicinity of Thoiry before heading back towards the pass, and noted that the aeroplane appeared lower than usual.
Several witnesses near Col des Prés saw the aeroplane flying low, at a height of several tens of metres above the trees, heading towards the pass. One witness saw a right turn at low height. All witnesses reported hearing a loud noise and seeing smoke seconds after the aeroplane passed.
At 19:11, the rescue services received a signal from the aeroplane’s emergency locator transmitter. At 19:40, the wreckage, on fire, was located.
Aeroplane Information
The aeroplane was a Flight Design CTLS-ELA, a two-seater LSA-certified aeroplane powered by a 100 hp naturally-aspirated injection engine (ROTAX 912 iSc2 SPORT) with a Neuform CR3-65-47-101.6 three-blade propeller. It was equipped with an airframe emergency parachute. At the time of the accident, the engine had logged 213 h and the airframe 155 h. The last 100-h inspection was on 10 June 2021 at 150 h.
One week before the accident, the engine experienced temporary overheating during an instruction flight. An unscheduled maintenance operation was carried out, and no anomalies were observed in the subsequent three flight hours.
The estimated weight at take-off from Annecy was near the maximum permissible but within limits; balance was compliant.
Pilot Information
The 43-year-old instructor held a Commercial Pilot Licence (CPL(A)) with valid SEP, MEP, IR/SE, and IR/ME ratings. He held a Flight Instructor rating (FI(A)) issued in 2011 and a Type Rating Instructor in complex HPA aeroplanes (TRI(SPA)) issued in 2017. He also held a microlight pilot licence and had previously held a glider pilot licence (2002–2008). He had a mountain wheel rating from 2017 to 2020 that had not been revalidated. According to statements, he was one of the most experienced instructors at Alpes Aéro for mountainous area flying, but was not a mountain flight instructor.
He had logged over 3,400 aeroplane flight hours, with 75 hours in the previous three months: 58 hours as pilot on twin-engine jet aircraft (Embraer Phenom 300, Cessna Citation C525b), and 17 hours on single-engine piston aeroplanes (SR22, C170, CTLS), including 14 hours as instructor on the CTLS.
His mountain experience included completing mountain rating training at Chambéry in May–June 2017 (14 hours on Jodel D113).
Meteorological Information
On the day, weather conditions were suitable for VFR flight. Météo-France reported a southwesterly wind of around 10 kt, possible convective clouds near high terrain with strong gusts and downdrafts, QNH 1014 hPa at Chambéry and 1016 hPa at Annecy, visibility >10 km, and temperatures of 31°C at about 1,000 ft and 23°C at 3,600 ft. A yellow heatwave warning was issued for Savoie.
Glider pilots on the western slope of Margériaz ridge reported calm wind at ground level but increasing wind from the southwest at around 1,200 m, with steep climbs (3–4 m/s) and likely downdrafts on the eastern slope (valley leading to Col des Prés). Several local pilots stated that flying over Col des Prés with a southerly or southwesterly wind could be treacherous, with turbulence and downdrafts, and that sufficient altitude margins were advisable.
At around 19:00, a section of the western slope of the valley was in shadow; the wreckage was on the sun/shade boundary.
Site and Wreckage Information
The wreckage was in a pasture at 3,632 ft (approx. 1,100 m), about 1.5 km below Col des Prés pass (3,724 ft). The bottom of the valley from Thoiry to the pass has an upward slope of approximately 6–9%. The area is not suitable for a forced landing due to vegetation.
The aeroplane was completely destroyed by fire after impact. Examination of the site and vegetation marks indicated that the right wing very likely struck trees during a right turn. The aeroplane turned over on contact with vegetation before ground collision.
The rudder and central part of the elevator were very probably destroyed by fire, but control linkages for elevator and rudder were probably continuous at impact. Aileron and flap continuity could not be fully checked. Flap position could not be determined.
Three propeller blades broke at their base and were found in vegetation. The engine was burnt and not examined further. Damage to blades and debris indicated the engine was operating at impact, but torque could not be determined.
The airframe parachute and ballistic release were destroyed; the parachute had not been activated.
Examination of the wreckage revealed no element that may have contributed to the accident. Data could not be retrieved from computers or mobile phones due to fire damage.