What happened
On March 25, 2017, a Robin DR400-180 registered F-GORD, operated by Aéroclub AGILE, was performing a local flight at Lognes-Émerainville aerodrome. The pilot was accompanied by three passengers. During the landing phase on runway 08, the pilot elected to increase the approach speed to 140 km/h in full flaps configuration to compensate for reported wind conditions.
Upon touchdown of the nose gear, the aircraft began to veer to the left. The pilot reported that rudder inputs were ineffective. The aircraft subsequently exited the runway to the left near a taxiway, striking a signpost which was destroyed. The aircraft sustained heavy damage but no injuries were reported among the four occupants.
The investigation
The investigation focused on the aerodynamic behavior of the aircraft during the landing roll and the pilot's technique. Investigators analyzed the meteorological conditions, noting a wind of 050° at 13 knots with gusts up to 21 knots. While the pilot's approach speed was significantly higher than the stall speed for the aircraft's weight (approximately 85 km/h), the investigation specifically examined the phenomenon of "wheel barrowing."
Investigators also reviewed the pilot's training and flight manual instructions. It was noted that the pilot had been taught by an instructor to push the control column forward after landing. However, the manufacturer's manual suggests maintaining back pressure for short landings and does not recommend the forward movement used by the pilot.
Findings
- The primary cause of the runway excursion was wheel barrowing, a phenomenon where the nose gear carries an excessive portion of the aircraft's weight, causing the plane to pivot rapidly around the nose wheel in a crosswind.
- The occurrence was driven by an excessive approach speed of 140 km/h, which is much higher than necessary for the aircraft's actual weight of less than 850 kg.
- The use of full flaps and the pilot's technique of pushing the control column forward contributed to the instability.
- The practice of pushing the nose gear forward to ensure it is unlocked is dangerous at high speeds as it increases the risk of the nose gear taking too much load.
Safety action
Following the accident, the aero club provided pilots with a new reference table indicating the appropriate approach speeds based on the aircraft's weight. Additionally, instructors were reminded of proper landing techniques to prevent similar occurrences.