What happened
On July 15, 2007, at approximately 21:25, a private Dyn’Aero MCR 4 S, registration F-PRSM, was performing a local flight at Royan aerodrome. The pilot, who was accompanied by three passengers, had decided to conduct a short flight despite observing deteriorating weather conditions, including approaching thunderstorms and increasing wind speeds.
After taking off from runway 28, the pilot transitioned to a downwind approach for landing. During the final approach, the pilot deployed the first stage of flaps and stabilized the airspeed at approximately 130 km/h. At an altitude of roughly 200 feet, the pilot deployed the second stage of flaps, a technique used to improve glide control. This action caused the airspeed to drop to 120 km/h without a corresponding increase in power, resulting in a steeper descent profile that brought the aircraft short of the runway threshold.
As the aircraft reached the flare, a wind gust caused the right wing to lift abruptly. The pilot attempted to correct the movement with right rudder and aileron input, but the wheels contacted the runway before the threshold. The aircraft subsequently veered left off the runway, colliding with several obstacles, including a runway edge light and a lateral marker, before coming to a stop in the grass.
The investigation
The investigation focused on the aircraft's flight path and the pilot's decision-making process in the context of the prevailing meteorological conditions. Investigators examined the pilot's use of flap settings and airspeed management during the final approach. The investigation also reviewed the weather data from Météo-France, which recorded winds of up to 39 knots near the storm cell, significantly exceeding the aircraft's demonstrated crosswind limit of 20 knots.
Findings
- The primary cause of the accident was the decision to fly in unfavorable meteorological conditions.
- The aircraft's airspeed decreased to 120 km/h following the deployment of second-stage flaps without a compensatory increase in engine power, leading to an undershot landing.
- The aircraft encountered wind gusts that exceeded the demonstrated crosswind limit of 20 knots.
- The impact resulted in significant damage to the left wing and tail strut of the Dyn’Aero MCR 4 S, as well as damage to runway lighting and marking equipment.