What happened
On May 16, 1998, a two-seat Solar Wing ultralight, identified as 42-EU, was engaged in a recreational flight near Mably, France. The pilot had departed from the Mably ultralight airfield as part of a group of three aircraft, intending to fly toward the Puy de Dôme with a scheduled stop in Maringues.
During the return leg of the flight, while operating west of the Monts de la Madeleine, the aircraft encountered significant atmospheric instability. The region was experiencing a wave system near Vichy-Roanne, which likely produced rotors near the terrain and moderate to strong turbulence. While navigating these conditions, the aircraft was suddenly destabilized by a powerful gust. Although the pilot managed to regain control of the aircraft, the engine subsequently failed.
Following the engine shutdown, the pilot made two unsuccessful attempts to restart the engine. With no other options available, the pilot attempted an emergency landing in a nearby field. The chosen landing site was a heavily plowed field situated on a steep 25% slope, located on the leeward side of the terrain. During the final approach, the aircraft struck the ground and was heavily damaged. The pilot sustained one injury.
The investigation
The investigation focused on the sequence of events leading to the engine failure and the subsequent impact. Investigators examined the aircraft's fuel system and the meteorological conditions present at the time of the accident. The investigation confirmed that the aircraft was carrying fuel in two 20-liter tanks, which were found to contain 3 and 6 liters respectively at the time of the crash. The investigation also assessed the impact of the local weather patterns, specifically the presence of mountain waves and turbulence, on the aircraft's stability and engine performance.