Air France jet's mid-Channel u-turns mystery

AN Air France plane from Paris to San Francisco has performed a u-turn over the English Channel.

Air France plane makes u-turn over English Channel

Radar shows the aircraft has performed several loops over the sea but it is not yet known why.
The pilot has not declared an emergency. 

The jet came down with a 'heavy landing' while returning to Charles de Gaulle airport in Paris, according to reports. The landing was with greater vertical speed and force than a normal landing.