What happened
On 23 July 2019, a B&F Light Aircraft FK9 Mark 4 microlight, identified as 09BO, was performing a cross-country flight from Dax to Calviac. During the flight, the pilot briefly diverted to Agen to repair a loose wing leading edge protection strip before continuing to his destination.
Upon arriving at the Calviac private aerodrome, the pilot entered the circuit for runway 17. GNSS data from a portable tablet indicates that the pilot began a steady descent on a 7% slope during the downwind leg. As the aircraft reached the displaced threshold of the runway, the flight path showed a period of altitude stabilization consistent with a flare, followed by a leftward heading change and a slight increase in altitude. During this maneuver, the aircraft struck trees bordering the runway at a steep angle with a left roll of approximately 90 degrees. The impact resulted in one fatality and the destruction of the aircraft.
The investigation
The BEA examined the wreckage, the site, and several on-board electronic systems, including an EFIS display and a GNSS receiver. While the aircraft's computers did not record specific flight data, recovered tracks from the pilot's navigation tablet provided the flight path. The investigation also reviewed the aerodrome's characteristics, noting the 620-meter paved runway featured a convex profile and a narrow 5-meter width.
Investigators also analyzed meteorological conditions, which included temperatures of 34°C and winds of 10 to 15 knots. The investigation considered the pilot's experience, noting he was a highly experienced pilot with approximately 1,100 hours in airplanes and 60 hours in this specific aircraft type. An autopsy revealed no underlying pathology that could have contributed to the accident.
Findings
- The aircraft was operating in turbulent aerological conditions caused by thermal phenomena and wind interacting with the nearby forest.
- Due to the runway environment, the pilot likely utilized a steep approach path with reduced engine power.
- The pilot likely perceived the remaining landing distance as insufficient, possibly due to the convex profile of the runway.
- The pilot initiated a go-around during the flare phase, but failed to maintain control of the aircraft's flight path following the application of power, leading to a leftward deviation into the trees.