Air accident investigators have said the Airbus registered inconsistent speed readings just before contact was lost, raising speculation that the pilots might inadvertently have flown at the wrong speed and precipitated the disaster.

Air France subsequently reported that it had noticed temporary loss of air speed data on previous Airbus flights due to ice collecting in the sensors, known as pitot tubes, and said it was speeding up a pre-planned replacement programme.

“As circumstances would have it, the first replacements arrived practically on the eve of the accident, on the Friday,” Gourgeon told a news briefing, adding, “I am not convinced that speed sensors were the cause of crash.”

Gourgeon said the planemaker had reassured clients that all three types of speed sensors available for its jets were safe, including the one used on the downed A330.

Industry sources said the planemaker had also ruled out for the time being that there was an electrical power failure or loss of cockpit instrument display on the Air France jet.