Air France received replacement airspeed sensors for its Airbus 330s three days before the fatal crash of Flight 447, but the airline's chief executive said Thursday that he was not convinced faulty monitors were the cause.

As storms bore down on the crash zone off Brazil, a French submarine searched the depths of the Atlantic Ocean for the black boxes that hold the best hope of finding out what did happen to the plane when the Airbus A330-200 flew into heavy storms May 31 with 228 people aboard.

So far, investigators have focused on the possibility that external speed monitors — Pitot tubes — iced over and gave false readings to the plane's computers.

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The plane's manufacturer Airbus encountered new problems Thursday when an Airbus 330-220 carrying 203 people made an emergency landing in Guam after an electrical problem sparked a small cockpit fire, Jetstar airline reported.

Company spokesman Simon Westaway said a pilot put out the fire with an extinguisher and no one was injured.

Airbus said it sent an advisory to airlines June 8 analyzing the automatic messages transmitted by the doomed Air France jet. Airbus spokesman Stefan Schaffrath said one of the messages showed a change of cabin pressure equal to an altitude change of more than 1,800 feet (548 meters) per minute. Schaffrath said Airbus does not have enough information to interpret this yet.

Replacement monitors for jet models of the same type as the crashed plane arrived three days before the fatal accident, airline chief executive Pierre-Henri Gourgeon told journalists on Thursday.

Air France ordered the replacements on April 27 after pilots noted a loss of airspeed data in flight on Airbus A330 and A340 models, he said.

The incidents were "not catastrophic" and planes with the old Pitots are considered airworthy, Gourgeon said.

"Because I am not convinced that the sensors are the cause of the accident, and we have said it, I had no need to issue a press release the day after the accident," Gourgeon added, responding to criticism that there was a lack of transparency.

"It's perhaps because we spend too much time with the families and not enough the press that you say this," he told an association of aerospace journalists in Paris.

In London, Tom Enders, president and chief executive of Airbus, told reporters on the sidelines of a news conference that suggestions in France's Le Figaro daily that its A330 and A340 aircraft would be grounded was irresponsible. He said it is not Airbus' decision whether to ground planes, but that of the regulatory authorities.'

Enders warned against "premature speculation" about the cause of the crash and said investigations can often take months.

Brazilian teams said they might end the hunt for floating bodies and wreckage next week. They found no bodies Wednesday, the first unsuccessful search day since Saturday, despite widening the search into the waters off the West African nation of Senegal.

Strong ocean storms were forecast to push into the area as early as Thursday, making it even tougher to track down remains that currents have scattered over a vast stretch of water.

Brazil's military announced late Wednesday that it tentatively has set a June 19 deadline to stop looking for bodies. A total of 41 bodies had been recovered.

Air France hopes that the plane's flight recorders will be recovered, but even without them examinations of the debris and bodies recovered from the crash are expected to shed new light on what happened to the plane, he said.

"We will know much more, I think, after the autopsies allow us to better understand the technical causes of death and when the debris have been examined by experts," Gourgeon said. "In a week there will be a little more information but the important point will be the recorders."

The French nuclear submarine Emeraude, hunting the data and voice recorders of the jetliner, cruised deep in the ocean to try to detect their signal pings.

Two Dutch ships were picking up U.S. pinger locating equipment to bolster the hunt.

Finding the boxes in the deep waters presents a formidable task, given the possibility that they could have come to rest amid jagged underwater mountains and that their signals will start to fade in about three weeks.

The submarine's crew plans to check 13 square miles (35 square kilometers) of ocean bottom a day, using sonar to try to pick up the boxes' acoustic beacons.

The United States has sent two underwater audio devices capable of picking up signals even at a depth of 20,000 feet (6,100 meters).

A Dutch search ship chartered by French investigators loaded one device Wednesday in the northern port of Natal and was expected to reach the search area by Sunday. A second Dutch ship was scheduled to pick up the second device this weekend.

Each device will be towed slowly in a grid pattern while 10-person teams watch for signals, U.S. Air Force Col. Willie Berges said.

If a box is located, the Emeraude will launch the remote-controlled mini-sub Nautile, which had a key role in the search for the wreckage of the Titanic, to recover it.