What happened
On Sunday, July 21, 2002, at 16:45, a Robin DR 400-140 B, registration F-GGSL, was performing a return flight from Millau to Grenoble le Versoud. During the takeoff roll on runway 32, the aircraft began to veer toward the left. The aircraft subsequently exited the paved runway surface, colliding with the PAPI (Precision Approach Path Indicator) system, and continued its path until it reached the parking area located in front of the south hangar.
At the time of the accident, the aircraft was operating near its maximum takeoff weight and at the rearward limit of its center of gravity. Meteorological conditions were characterized by CAVOK visibility, a temperature of 27 °C, and a crosswind from 280° at 10 to 15 knots. There were 4 persons on board, all of whom survived the incident.
The investigation
Investigators examined tire marks on the runway, which revealed that the aircraft was skidding to the right prior to exiting the paved surface. The pilot reported that during the takeoff roll, the control stick was positioned toward the windward side but not forward. To counteract a leftward yaw, the pilot applied right rudder.
As the takeoff roll progressed, the aircraft's pitch increased. As the nose gear strut extended, the nose wheel likely realigned with the longitudinal axis of the aircraft as it transitioned into the flight position. This left the pilot relying on the rudder, which was still relatively ineffective, to maintain the runway centerline. The pilot's application of right rudder, combined with likely use of the right brake, caused the aircraft to skid. A late reduction of engine power prevented the pilot from avoiding the PAPI installation and the subsequent excursion.
Findings
- The primary cause of the excursion was inappropriate takeoff technique during a crosswind while operating at the rearward limit of the center of gravity.
- The rearward center of gravity position and the rearward position of the control stick significantly reduced the effectiveness of the nose gear, making it difficult to counteract engine torque and the weathercock effect.
- The aircraft sustained damage to the left wing underside, the left flap, the left main landing gear, and the silencer, while the PAPI unit was destroyed.