The pilot, accompanied by two passengers, took off around 8:55 from Saint-François aerodrome bound for Marie-Galante aerodrome under a VFR flight plan. During the flight preparation, the pilot consulted the weather forecasts. He underestimated the impact of the forecast phenomena and the speed at which they were going to evolve and said that he could avoid them given that their probability of occurring was considered small. He did not update his information before leaving one hour later although the phenomenon observed was very dynamic. He started his flight in favourable local meteorological conditions without realising that the conditions at his destination were quickly deteriorating. He continued towards Marie-Galante although the phenomenon was intensifying.
The pilot probably flew a missed approach due to the reduction in visibility and started turning around at a low height by making a right turn. The presence of rain, which reduced visibility, combined with flight over water, in all likelihood deprived him of external visual references. The dangerous phenomena associated with the proximity of a cumulonimbus such as squall lines and windshear may have also led the pilot to lose control at low height.
The accident was the result of the pilot underestimating the danger presented by the development of a tropical wave and his decision to continue the flight when there were adverse meteorological conditions on the route and at destination. A programmed professional appointment with his passengers may have affected his discernment and incited him not to renounce carrying out the flight and to fly to destination.