A probe into the crash of AF 447, in which an A330 Airbus plane went down en route from Rio to Paris with the loss of all 228 people on board, has focused on a possible defect of the pitot airspeed sensors.

SNPL union spokesman Erick Derivry said he was informed at the weekend that Air France, which accelerated a programme to replace the suspect pitots following the crash, had completed the work.

"Air France has further speeded up the replacement of the probes compared to its initial plan," he said.

The carrier, Airbus and the French agency probing the accident all say there is no proof yet the airspeed monitors were to blame.

But Air France said the devices would be replaced on the entire fleet as a precaution, after the worst air disaster of the airline's 75-year history.

The Airbus A330 went down as it was flying through turbulence caused by a storm and the jetliner sent out 24 automated messages about abnormalities in the final minutes of the flight.

Aviation experts have said that if pitots give false speed readings to the cockpit, it can cause the autopilot to shut down and in extreme cases the plane to stall or fly dangerously fast, possibly causing a high-altitude breakup.

A company report seen by AFP showed that Air France Airbus jets experienced at least five incidents last year in which airspeed probes malfunctioned, two of which triggered stall alarms.

Air France's entire fleet of 15 A330 and 19 A340 planes were fitted with the improved sensors, according to the pilot union.

Airbus celebrates at Paris Air Show

As the mystery lingered over the fate of the plane, Airbus celebrated its first big deal of the year with the sale of 24 medium-haul A320 airliners at the Paris air show.

The world's biggest air show opened earlier in Le Bourget, north of Paris, under a cloud of gloom from the crash and the economic crisis battering the aviation industry.

The search for bodies and remnants of the lost airliner entered its third and possibly final week Monday with the focus on locating the "black box" recorders that could hold the key to its plunge into the Atlantic.

The Brazilian and French navies have recovered 49 bodies as well as pieces of the aircraft, including a large fragment of its tail.

But a nuclear submarine and another vessel equipped with listening devices have yet to detect the ping of the black boxes as they comb an enormous expanse of the high seas 1350 kilometres off the Brazilian coast.

The flight recorders may be on the ocean floor at a depth of 3500 meters and they are programmed to emit a signal for one month.

Most of the bodies have been transported to Recife, on Brazil's north-eastern coast, where a team of doctors is examining them to establish their identities.

One of Air France's insurers, Axa Corporate Solutions, said the airline will receive compensation of up to 67.4 million euros (93.4 million dollars) for the loss of the Airbus A330.

The carrier is also responsible for compensating the families of the 228 people on board and has separate insurance to cover those costs.

Among the 228 victims were people of 32 nationalities, including 72 French nationals, 59 Brazilians and 26 Germans.

The Brazilian military has begun talking about an end to the search, with Brigadier Ramon Cardoso saying it will continue at least until Friday. That deadline however may be reassessed, he said.

AFP