What happened
On October 5, 1999, a Robin DR 400-120 aircraft, registered F-GSRF, was performing a local flight from the Saint-Gervais airfield. The pilot, who also owned the aerodrome, began the takeoff roll on runway 01. After traveling approximately 400 meters, the pilot noted a speed of 100 km/h. At this point, the pilot deployed the second flap setting (landing configuration) to increase lift and applied significant back pressure on the control column.
The aircraft lifted off the unpaved surface but settled back onto the ground after roughly 15 meters of flight. The aircraft continued to roll for another 90 meters before the right landing gear struck the edge of a ditch. The aircraft finally came to a stop 40 meters further along the path. The incident resulted in damage to the right wing and right landing gear.
The investigation
The investigation examined the aircraft's performance relative to the manufacturer's flight manual and the pilot's actions during the takeoff roll. The airfield at Saint-Gervais featured an unpaved, 450 x 30 meter grass runway with a firm, mown surface and no longitudinal slope.
Technical analysis compared the actual takeoff roll to the manufacturer's specifications. Under the prevailing weather conditions, the manual indicated a required takeoff roll of approximately 180 meters and a takeoff speed of 100 km/h. Furthermore, the investigation reviewed the standard operating procedures regarding flap settings, noting that the manufacturer's manual specifies that the only authorized takeoff procedure is to maintain the first flap setting throughout the entire takeoff sequence.