Air France has said all its flights using long-haul Airbus jets will be equipped immediately with new speed sensors after last week's disaster over the Atlantic, a pilots' union said today. The pitot tubes that gauge speed have become the focus of an investigation into the crash after messages showed they provided "inconsistent" data to the pilots and might have played a role in the June 1 crash.

One Air France union urged its pilots to stop flying Airbus A330 and A340 aircraft until the old sensors were replaced and the company has since committed itself to a swift change-out, a union official said. "Air France has provided us with an extremely proactive and much accelerated replacement program," said Erick Derivry, spokesman of the main SNPL pilots union.

"From today, all Air France A330 and A340 flights will use planes equipped with at least two new sensors out of three (on board)," he told France Info radio. Air France, which has 19 A340s and 15 A330s, declined to comment.

The pitot tubes are small probes on the exterior of the fuselage that measure the pressure of air rushing into them and thereby gauge the plane's speed. The French air accident agency has said it is too early to pinpoint any possible cause for the crash, but noted there were apparent problems with the jet's speed readings.

This has fueled speculation that its pitot tubes may have iced up, feeding wrong data into the cockpit which might have confused the plane's fly-by-wire computer system and its pilots. Air France said at the weekend it had noticed icing problems on the speed sensors in May 2008 and had asked Airbus for a solution to reduce or overcome the difficulty.

Airbus responded by reaffirming existing operating procedures, according to Air France in a statement on Saturday. Air France said tests had later convinced it that probes developed for another model would be more efficient and that it had decided to go ahead and start fitting them from April 27 without waiting for further testing proposed by the plane maker.

The A330 that crashed had not yet been modified. Airbus has declined to comment on the Air France statement. Airbus Chief Executive Tom Enders told reporters in Munich his company was working closely with authorities and was keeping clients informed.