What happened
On the evening of June 12, 2000, a Robin DR 400-140 B, registration F-BXJO, was completing a one-hour flight as part of a trip. While performing a direct approach to the unpaved runway 30 at Thouars, the aircraft touched down approximately 25 meters before the runway threshold. The aircraft entered a field of rapeseed, where the crop height was roughly 1.40 meters. Upon contact with the vegetation, the left wing acted as a brake, causing the aircraft to pivot 90 degrees to the left. The sequence ended with the aircraft coming to rest on its nose at the edge of the runway.
There were three people on board, including the pilot, and the aircraft sustained damage.
The investigation
The investigation focused on the pilot's perception of the runway environment during the final approach. Meteorological conditions at the time of the accident included visibility greater than 10 km, scattered clouds at 3,000 feet, and winds between 06 and 10 knots from 280° to 320°. Notably, the sun was positioned at an azimuth of 303°, with sunset occurring just 15 minutes after the accident.
The pilot reported that during the final approach, the sun appeared to disappear below the horizon, creating a shadow zone that prevented him from clearly identifying the start of the runway. The pilot was wearing corrective prescription sunglasses at the time of the incident. Upon removing the glasses, the pilot realized that they had contributed to his difficulty in perceiving the surrounding environment.