Investigations into the loss of the Air France Airbus A330 over the South Atlantic have determined that the aircraft did not break up in mid-air, and did not transmit a distress message.
The French Bureau d'Enquetes et d'Analyses, in an update to the flight AF447 inquiry today, has also stated that it will stop the current undersea search operation for the flight recorders on 10 July.
Speaking at the briefing, the BEA's Alain Bouillard said: "As of today we are far from having any real idea of the causes of this accident."
But he says that bottom-to-top deformation of structural components recovered from the water showed the aircraft appears to have struck the ocean surface with a "sharp vertical" acceleration.
The nature of the damage, he says, indicates that the jet was "not destroyed in flight".
Bouillard says the aircraft's maintenance complied with requirements, there were no reports of technical problems from the crew, and there was no distress call - either to air traffic control or other aircraft - at the time of the loss on 1 June.
Search teams are still trying to locate the flight recorders but the sonic transmitters are only required to operate for 30 days. The current search effort will be abandoned on 10 July and a second phase, using different techniques, will start after 14 July.
"We refuse to believe that we will not find them," says Bouillard.
He says the BEA's analysis of the event has also included examination of the behaviour of three other flights in the vicinity: an Iberia Airbus A340, 12min behind the A330, another Air France A330 which was 37min behind, and a Lufthansa Boeing 747-400 which was 20min away.
All the aircraft were travelling at flight levels 350-370, around the same altitude as AF447. Bouillard says the aircraft flew to avoid storm cells between the ORARO oceanic waypoint and the TASIL waypoint some 120nm northeast.
These flights experienced "moderate turbulence", he says, and diverged from their courses by 10-80nm.