What happened
On February 12, 2004, a Cessna 150 M, registration D-EHPF, departed from Le Castellet aerodrome at 10:05 AM, bound for Valence. While cruising at flight level 65, the pilot encountered increasingly heavy winds and turbulent conditions. In an attempt to find smoother air, the pilot initiated a descent toward 4,000 feet.
During this descent, the aircraft encountered severe turbulence that resulted in a near-loss of control. The force of the turbulence caused the pilot to strike the cabin wall, breaking a camera and scattering charts and paperwork throughout the cockpit. Overwhelmed by the intensity of the weather, the pilot determined that continuing to the destination or diverting to another aerodrome was not an option. After searching for approximately fifteen minutes, the pilot identified a wheat field near a village, roughly 200 meters in length, and successfully performed an emergency landing in the field.
The investigation
The investigation focused on the pilot's decision-making and weather awareness prior to departure. While the pilot had reviewed meteorological information, including TEMSI charts, TAF, and METAR reports, the day before the flight, the AFIS agent at Le Castellet had specifically advised against flying due to high winds, suggesting conditions would improve the following day.
On the morning of the flight, the pilot observed local winds of 10 to 12 knots and good visibility. However, the pilot departed before the AFIS service had opened and failed to check updated weather reports for the intended route. While local conditions at the departure point were favorable, the route included areas of significant turbulence, particularly near Valréas, which is known for high turbulence during Mistral wind events.
Findings
- The primary cause of the incident was insufficient flight preparation regarding the weather conditions along the intended route.
- The pilot failed to consult updated meteorological information for the flight path after departing before the official opening of the AFIS service.
- The aircraft encountered severe turbulence characteristic of the region during Mistral wind conditions.