Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.
The pilot sat in the rear seat, accompanied by a passenger sat in the front seat, took off at around 13:00 from Clermont-Ferrand Auvergne airport (Puy-de-Dôme) bound for Brioude Beaumont aerodrome(Haute-Loire). The pilot flew over Issoire Le Broc aerodrome(Puy-de-Dôme) at low height to wave to friends present at the aerodrome, then he regained altitude before heading to his destination. Shortly after, when the aeroplane was in level flight, the engine shut down. The pilot lost control of the aeroplane, which collided with the ground with a steep nose-down attitude.
During the flight, the seal failure between the accessory section and the engine casing caused a gradual oil leak that could not be detected by the pilot, along with emission of black smoke. The lack of engine lubrication caused the engine to seize and shut down.
The pilot started to descend to perform a forced landing.
During this descent, the pilot lost control of the aeroplane. The low height at which this loss of control occurred did not enable the pilot to regain control of the aeroplane.