Spotter planes were dispatched in a bid to locate the jet in a vast area of ocean between Brazil and Africa, but officials said there was little hope of survivors from what appears to be the worst air accident in over a decade.
'The prospects of finding any survivors are very slim,' a grim-faced French President Nicolas Sarkozy said after talking to stunned relatives of missing passengers. 'It's a catastrophe the likes of which Air France has never seen.'
Although the exact cause of the crash remained a mystery, Air France's chief executive said the Airbus A330 had sent a series of error messages shortly after crossing an area of major turbulence.
'A succession of a dozen technical messages' sent by the aircraft around 0215 GMT (10.15am Singapore time) showed that 'several electrical systems had broken down' which caused a 'totally unprecedented situation in the plane,' said Pierre-Henry Gourgeon.
'It is probable that it was shortly after these messages that the impact in the Atlantic came,' he told reporters at Charles de Gaulle airport, where the flight was meant to have landed on Monday morning.
Airline officials had earlier said the plane was probably hit by lightning, but Mr Gourgeon declined to make a direct link between weather conditions and the error messages.
Brazilian President Luiz Inacio Lula da Silva said he held out hope for survivors, but added that earlier he had spoken with French President Nicolas Sarkozy by telephone 'and really it was an exchange of condolences.'
European Commission chief Jose Manuel Barroso sent a message of solidarity to both presidents, and expressed his 'deepest sympathies' to the loved ones of those on board.
If it is confirmed that all 228 people on Flight AF 447 are dead, it would mark the worst loss of life in Air France's history and civil aviation's worst accident for more than a decade.
Timeline of events
All times in Brazilian local time:
- 7.03pm Sunday: Air France says plane left Rio de Janeiro.
Brazilian Air Force says plane left at 7.30pm
- 10.30pm Sunday: Air France says plane has last contact with Brazil air traffic control. Brazilian Air Force says last radio contact at 10.33 pm, 565km from north-eastern Brazilian city of Natal.
- 10.48pm Sunday: Brazilian Air Force says last radar contact with Brazil indicated plane flying normally.
- 11pm Sunday: Air France says plane entered zone of storms and high turbulence.
- 11.14pm Sunday: Air France receives automatic message indicating electrical circuit malfunction.
- 11.20pm Sunday: Brazilian Air Force says plane fails to make previously scheduled radio contact with Brazil. Brazil notifies air traffic control in Dakar, Senegal.
- 2-3am Monday: Air France says French military radar begins searching for plane.
- 2.30am Monday: Brazilian Air Force says it mounts search and rescue mission with two planes.
- 4.30am Monday: Air France says it sets up crisis centre.
- 6.15am Monday: Plane?s scheduled arrival in Paris, according to Air France.
- 8.30am Monday: Brazilian Air Force says it was told by Air France about the message the plane sent to the company. The message indicated technical problems, including a loss of pressure and an electrical system failure, Brazilian Air Force says. (AP/AFP)