ADAM SCHRECK, AP Business Writer

DUBAI, United Arab Emirates (AP) — Some of the biggest operators of the plane involved in the recent Air France crash said Tuesday they use a different brand of airspeed sensor than those aboard the doomed flight, distancing themselves from instruments seen as a possible factor in last week’s accident.

Focus on the sensors known as Pitot tubes intensified after Air France issued a statement last week saying it was in the process of replacing the instruments on the Airbus A330 model.

The cause of Air France Flight 447’s crash on May 31 remains unclear, but one theory is that the sensors became iced over and gave incorrect readings. That in turn could have sent faulty information to flight computers and caused the plane to fly either too slow or too fast.

The sensors aboard the plane were made by France’s Thales Group and had not yet been replaced. The plane disappeared over the Atlantic Ocean while on a flight from Rio de Janeiro to Paris, killing 228 people on board.

Caroline Philips, a spokeswoman for defense and aerospace manufacturer Thales, confirmed the company made the Pitot tubes on the jet that crashed. Thales, however, but did not say how many other planes use the devices.

Emirates airline, the Middle East’s largest carrier and one of the biggest users of the A330 model, stressed that the Pitot tubes aboard its planes were made by U.S. manufacturer Goodrich rather than Thales.

“We have not experienced any issues with our probe units as described in the media relating to the recent disaster,” Adel al-Redha, executive vice president for engineering and operations, said in an e-mail.

“Emirates is in full compliance with all standard operating procedure recommendations issued by aircraft manufacturers, as well as with requirements stipulated by international air safety and regulatory authorities,” he said.

The Dubai-based carrier operates 29 of the A330-200 variant, more than any other airline. The model is the same used on Air France Flight 447.

Etihad Airways, an Abu Dhabi-based carrier that is likewise among the biggest A330 operators, said its planes are also equipped with Goodrich speed sensors.

At an aviation conference in Malaysia, a Qantas Airways official noted that the Australian carrier likewise uses Goodrich rather than Thales sensors.

“We are not concerned because it’s a different system in our aircraft,” Qantas General Manager for Government and Corporate Affairs David Epstein said.

Concerns over the sensors led an Air France union Monday to call on its pilots to refuse to fly Airbus A330s and A340s unless at least two of the three Pitot sensors had been replaced. The Alter union represents about 12 percent of Air France pilots.

Meanwhile, Brazil’s private Agencia Estado news agency said the country’s largest airline, TAM, has already replaced the Pitot tubes on its Airbus jets.

TAM Linhas Aeras SA made the replacements after a 2007 recommendation from Airbus, chief executive David Barboni told Agencia Estado.

About 70 airlines operate versions of the 600 twin-engined A330s in use around the world.

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Associated Press Writers Greg Keller in Paris, Eileen Ng in Kuala Lumpur, Malaysia, and Alan Clendenning in Sao Paulo contributed to this report.