Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.
After 30 minutes of exercises near the ground at Libourne Artigues-de-Lussac aerodrome, the pilot-in-training took off on QFU 04. While the helicopter was flying in a straight line at low height in the downwind leg, a carburettor malfunction, due to a float that was not leaktight, caused an engine fuel supply fault leading to a reduction in power.
In all likelihood, the instructor took the controls and initiated an autorotation or a rapid descent that he was unable to control correctly to land the helicopter. With the wreckage facing north-east, it is likely that the pilot tried to line up for final facing into the wind, which would explain the turn observed by the witnesses.