Air France has emphasised the evidence of a technical malfunction on the Airbus A330 which crashed in the South Atlantic two years ago, after French investigators detailed the final minutes of flight AF447.
Preliminary information shows that the aircraft climbed and stalled at high altitude, and that the crew failed to recover from the stall before the A330 struck the ocean surface.
France's Bureau d'Enquetes et d'Analyses confirmed there was a sudden change in displayed speeds and that there was a discrepancy between that shown on the primary flight display and that on the standby instrument system.
The non-flying pilot said that the aircraft had "lost the speeds" and then mentioned that the aircraft had switched into 'alternate' law - a normal response from the aircraft in the event of unreliable speed information.
BEA does not mention any reason for the inconsistent speed indications.
But Air France said: "It appears...that the initial problem was the failure of the speed probes which led to the disconnection of the autopilot and the loss of the associated piloting protection systems, and that the aircraft stalled at high altitude."
The airline does not discuss the crew's response to the stall beyond pointing out that the captain, having left the cockpit to rest, quickly returned to address the situation.
"The crew, made up of three skilled pilots, demonstrated a totally professional attitude and were committed to carrying out their task to the very end and Air France wishes to pay tribute to them," said the carrier.
"All the data collected must now be analysed. It will only be at the end of this complex task, which requires patience and precision, that the BEA will be able to establish the causes that led to the disaster."
Airbus has issued only a limited response to the AF447 update, in which it said the BEA's information "constitutes a significant step towards the identification of the complete chain of events".