Cat. 3 investigation report: report concerning an occurrence with limited consequences, based on one or more statements not independently validated by the BEA.
This is a courtesy translation by the BEA of the Final Report on the Safety Investigation published in May 2021. As accurate as the translation may be, the original text in French is the work of reference.
Note: The following information is principally based on statements made by the pilot. This information has not been independently validated by the BEA.
1 - HISTORY OF THE FLIGHT
On returning from a local flight, the pilot flew overhead the facilities. He observed that the windsock indicated a southerly wind of 10 to 15 kt consistent with the wind at departure. He joined the circuit for paved runway 11. During the landing, in crosswind conditions, the aeroplane bounced slightly after the first touchdown. After the second touchdown, the pilot felt a vibration that would continue during the landing run phase. He felt that the aeroplane was snaking down the centreline. As he did not understand what was causing the problem, he braked gently in order not to skid. Aware of the presence of other traffic in the aerodrome circuit, he decided to vacate the runway quickly. During the left turn, the aeroplane tilted to the left and the propeller touched the ground. Then the aeroplane tilted to the right and the tip of the leading edge of the right wing touched the ground. The nose gear broke. The aeroplane came to rest on the runway.
2 - ADDITIONAL INFORMATION
2.1 Pilot information and statement
The 37-year-old pilot, held a PPL(A) licence. At the time of the accident, he had logged 131 flight hours, including 122 hours on the DR400. In the last 90 days, he had flown 9 hours on the PA28, as part of IR-SE training. In the last 30 days, he had flown 6 hours.
His last flight on the DR400 was on 19 October 2020. This was his PPL(A) licence revalidation flight.
On 4 July 2020, he had flown a training in crosswind conditions flight with an instructor, in accordance with a rule established by his club. This flight was performed on a DR400.
The pilot had never experienced the shimmy phenomenon in flight. He recalled studying it theoretically during his PPL training in 2016. He also mentioned that an article on the subject published in the magazine Info-Pilot, was posted at the club. He actually had this article in his flight documentation. He recalled reading it twice, the last time almost six months before the event. He stated that, during the occurrence, he did not make the connection with the shimmy phenomenon and did not understand the cause of the vibration during the landing run.
The pilot indicated that he had felt under time pressure because of the presence of another aeroplane in the circuit and because he was aware of the time needed to vacate the runway (see § 2.2). For this reason, he decided to start a 180° turn at a speed that he considered in retrospect to be slightly faster than usual. He thought that his speed during the turn was between 20 and 30 km/h. His recollection was that the turn was no tighter than usual, but that the pressure on the rudder pedals may have been greater than usual.
The pilot explained that the club's DR400s have a handbrake type lever for braking. He had never had trouble in balancing his braking during his flights on these planes and considered that he braked softly during the landing run.
The pilot indicated that the landing technique he had been taught was to land at a speed of 70 kt with the flaps extended to the second flap detent position. In crosswind conditions, he was to increase the speed by 10 kt on final. The approach speed that he adopted in such conditions was therefore 80 kt.
2.2 Aerodrome information
Valenciennes Denain aerodrome is an aerodrome open to public air traffic. As the occurrence took place outside the AFIS opening hours, the aerodrome’s A/A frequency was in use.
The aerodrome has three runways: one unpaved runway 06-24 and two parallel runways 11-29, one of which is paved.
Due to the organization of the runways and taxiways and the associated rules of use, when landing on paved runway 11, the pilot has to turn around and backtrack on the runway to vacate it via a taxiway close to threshold 11.
2.3 Crosswind landing
Note: The F-BXRV manual could not be consulted. The following information is based on the manual of another DR400-160 from the BEA technical library.
The procedure for a normal landing on a DR400-160 is to land with the flaps extended to the second flap detent position and a final approach speed of 65 kt.
In case of crosswind, the procedure is to extend flaps to the first flap detent position and adopt a final approach speed of 70 kt.
 If necessary, increased by half the value of the gust speed.