Accident to the Cessna 172 - S registered F-OKDV on 16/10/2019 at Plaine des Sables (La Réunion)

Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.

The pilot and three passengers took off from Saint-Pierre aerodrome for a flight over Piton de la Fournaise. The route taken was that usually used by pilots wishing to fly to the volcano and departing from Saint-Pierre. Altitude must be gained along the Langevin ravine before approaching the Plaine des Sables plateau.
On the day of the accident, the Reunion Island was under the influence of moderate trade winds. The east wind was well established, especially at low level. This meteorological situation was of a nature to cause downdraft phenomena over the southern terrain of the Reunion, and particularly in the area of the Langevin ravine and Plaine des Sables. Several other aircraft thus flew over the volcano area at high altitude in order to fly in less turbulent conditions.
The analysis of photos and a video taken on board showed that F-OKDV had climbed from point PS with a higher rate of climb than that specified in the flight manual at the maximum weight. The pilot probably used the dynamic uplifts to move up the Langevin ravine. 
The aeroplane crossed Cassé de la Plaine des Sables and approached the plateau, exposed to strong winds according to witnesses on the ground, at a height of less than 300 ft.
It then turned right a few seconds before colliding with the ground. The investigation could not determine the reason for this entry into a right turn. 
In the absence of direct witnesses and recorded data, it was not possible to specify with certainty, the circumstances in which the collision with the ground occurred. The conclusions of the spectral analysis tend to rule out the possibility of an engine malfunction at the end of the flight. Observations at the site and on the wreckage suggest that the pilot lost control of the aeroplane during the turn.