Cause of death: boat accident
Didier Joseph Louis Pironi (26 March 1952 – 23 August 1987) was a French racing driver and later power boat racer. During his career, he competed in 72 Formula One World Championship Grands Prix, driving for Tyrrell (1978–1979), Ligier (1980) and Ferrari (1981–1982), but his F1 career ended after a practice crash at the 1982 German Grand Prix. He won the 24 Hours of Le Mans in 1978 driving a Renault Alpine A442B.
Source : Wikipedia