PICTURES: Sete somersault starts turn one carnage.

Sunday's Catalan Grand Prix saw a heart-stopping turn one accident, which began with a somersaulting Sete Gibernau and ended with six riders in the gravel trap.

The incident occurred when the two factory Ducatis of Gibernau and Loris Capirossi tangled in the braking area; Gibernau appearing to slide towards his team-mate - before being sent flying over the handlebars into a full 360-degree flip after his front brake lever was hit, leaving both man and machine cartwheeling down the track.

The initial impact also caused world championship leader Capirossi to veer sideways into Marco Melandri - with both riders falling hard before slamming into the back of Dani Pedrosa and John Hopkins, who were braking as normal ahead of them. Kawasaki's Randy de Puniet was taken out separately as he avoided Gibernau's riderless bike.

Melandri was knocked unconscious as he became trapped between his own machine and that of Pedrosa, as the mass of riders and bikes all tumbled into the gravel trap. Hopkins was also sent straight on, and had to ditch his GSV-R to avoid hitting the air fence at the end of the gravel trap.

When the dust cleared, Melandri - who has won two races this season - was left motionless in the gravel trap before being carried away on a stretcher, while Capirossi - also initially out cold - and Gibernau joined him in being taken to the medical centre.

Melandri, Gibernau and Capirossi were then taken to hospital in Barcelona for further tests, but the first impressions are that all three are fortunately not seriously injured; Gibernau suffering a fractured collarbone, Melandri a dislocated collar bone and Capirossi abdominal bruising.