What happened
On April 26, 2008, at approximately 12:30 local time, an Aeroservices Guépard 912 V2 ultralight, identified as 11-GF, departed from Castelnaudary for a local aerial photography mission. The pilot and a passenger intended to photograph the village of Vaudreuille in preparation for an upcoming local event. During the flight, the pilot configured the aircraft with the doors open and the flaps extended to one notch to facilitate low-speed maneuvering.
While maneuvering south of the village at an estimated altitude of 1,000 feet, the pilot initiated a left-hand turn to reposition for another pass. During this turn, the aircraft's altitude decreased significantly without the pilot immediately noticing. As the aircraft exited the turn at a speed of approximately 90 km/h, the pilot realized the aircraft was sinking and applied full power. However, the aircraft entered a left-wing stall and struck the ground. The impact occurred near a hangar, where the aircraft came to rest on its back atop a scaffolding structure. The two occupants sustained slight injuries, but the aircraft was destroyed.
The investigation
The investigation examined the aircraft's weight and balance, as well as local meteorological conditions. While the pilot's manual indicated a basic empty weight of 262 kg, the aircraft's actual empty weight was recorded as 2FR3 kg. Calculations revealed that the actual takeoff mass of 466 kg exceeded the maximum allowable weight for this ultralight category, though the center of gravity remained within manufacturer limits.
Investigators also analyzed the local aerology. Although the weather was reported as CAVOK with a 10 to 15-knot wind, the investigation identified the presence of downdrafts caused by the Montagne Noire terrain. Local glider pilots, who were aware of these specific wind effects, had chosen not to fly that day due to the risk of these downdrafts, a phenomenon unknown to the pilot of the 11-GF.
Findings
- The primary cause of the accident was the pilot's focus on the photography mission at the expense of maintaining proper aircraft control and monitoring altitude.
- A contributing factor was the pilot's lack of familiarity with local aerodynamic conditions, specifically the downdrafts occurring on the leeward side of the nearby terrain.
- The aircraft was operating in an overweight condition, with the total mass exceeding the legal limit for a microlight/ULM.
- The aircraft was not equipped with a stall warning system.