RECIFE, Brazil/PARIS (Reuters) - Search crews retrieved four more bodies from a crashed Air France jet on Sunday, spotted other corpses and found a large amount of debris from the plane that plunged into the Atlantic ocean.

Six bodies have now been recovered from the plane, following the discovery of two unidentified males on Saturday, five days after the Airbus A330 crashed on its way from Rio de Janeiro to Paris killing all 228 people on board.

Investigators are considering the possibility that the speed sensors on Flight 447 may have iced up, and Air France said late on Saturday it was accelerating the replacement of speed sensors on all its Airbus long-haul planes.

Brazil’s navy said on Sunday it had retrieved three more bodies and France said a helicopter operating from one of its naval frigates had recovered another body from the world’s worst air disaster since 2001.

“Hundreds of items are being found and being stored until we know where they should go,” Brazilian Air Force spokesman Henry Munhoz told reporters in the northeastern city of Recife, where the bodies and debris will eventually be brought.

Several other corpses spotted on Sunday by Brazilian Air Force planes are expected to be picked up later in the day, search officials said.

Brazilian network Globo reported on its website that a refrigerated truck used to store corpses was waiting on the islands of Fernando de Noronha, 230 miles off the coast of Brazil.

Twelve Brazilian planes, one equipped with radar equipment that can detect material in the water, two French planes, one French ship and five Brazilian navy ships are searching the area about 680 miles northeast of Brazil’s coast.

SUBMARINE TO JOIN SEARCH

France has also sent a nuclear-powered submarine that should arrive on Wednesday to search for the black box flight data recorders that will be crucial to understanding why the modern plane fell from the sky as it passed storms on Monday.

The Emeraude is equipped with powerful sonars to help detect the black box’s beacons that stay active for 30 days.

The plane’s pilots may have set the aircraft at a dangerous speed because they were relying on faulty speed readings, investigators believe.

Air France said it had begun the switchover of speed sensors five weeks before the crash, but only after disagreeing with Airbus over the planemaker’s proposal to carry out tests before replacing them.

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An Airbus spokesman declined to comment and said it could only discuss the investigation with French air authorities.

The head of France’s air accident agency BEA said on Saturday it was too soon to say if problems with the speed sensors, known as pitot tubes, were in any way responsible.

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LOST DATA

The agency said the A330 had sent out 24 error messages in four minutes including one indicating a discrepancy in speed data. It said similar problems had happened before.

Air France said it had first noticed in May 2008 that ice in the sensors was causing lost data in planes like the A330, but that it failed to agree with Airbus on steps to take.

According to Air France, Airbus offered to carry out an in-flight test on new sensors this year but the airline decided to go ahead and started changing them anyway from April 27.

It did not say whether the crashed plane had the new sensors but its last maintenance hangar visit was on April 16.

Some of the A330’s 50 or so other operators defended the plane’s safety record at an airlines meeting in Kuala Lumpur on Sunday, saying the crash was an isolated incident.

But Airbus has faced problems with the speed sensors dating back to at least 2001, forcing changes in equipment as well as the pilot’s flight manual, according to online filings.

In 2001, France reported several cases of sudden fluctuation of A330 or A340 airspeed data during severe icing conditions and Airbus was ordered to change the cockpit manual, according to the U.S. Federal Aviation Administration.