What happened
On June 14, 2013, a Robin HR200-120B, registered F-GNNC, was performing its fourth solo cross-country flight. The student pilot departed from Saint-Cyr-l’Ecole for the Rouen-Vallée de Seine aerodrome. Upon arrival, the pilot joined the downwind leg for runway 22. During the final approach, the pilot configured the aircraft with landing flaps and maintained a speed of 70 knots.
While the flare was initially normal, the pilot reported feeling vibrations through the rudder pedals immediately upon touchdown. Following this vibration, the aircraft veered to the left. Despite the pilot's attempts to correct the deviation by applying right rudder, the aircraft exited the paved runway surface and came to rest in a drainage ditch located parallel to the runway.
The investigation
The investigation focused on the mechanical behavior of the aircraft during the landing roll and the environmental factors at the aerodrome. Investigators examined the meteorological conditions, noting a wind from 160° at 11 knots, resulting in a crosswind component of approximately 10 knots.
Technical analysis centered on the vibrations reported by the pilot. The investigation established that the vibrations in the pedals were likely caused by a nose gear shimmy. This unstable oscillatory movement occurs when excessive compression forces are applied to the nose gear, often triggered by high-speed landings. The investigation also assessed the site of the accident, noting that the ditch was located 75 meters from the runway centerline, which is within regulatory limits, though it had been involved in several previous runway excursions at this location.
Findings
- The primary cause of the excursion was the pilot's failure to take adequate corrective action to mitigate the nose gear shimmy, such as relieving pressure on the nose gear by pulling the control column aft.
- The heavy damage to the aircraft was caused by the impact with the drainage ditch located outside the runway strip.