A French nuclear submarine reached the crash zone of Air France Flight 447 on Wednesday to join the search for the plane's black boxes, which may be the key to determining what brought the Airbus down in the sea off Brazil with 228 people on board.
The attack sub Emeraude plans to trawl 13 square miles a day, using sonar to try to pick up the boxes' acoustic beacons or "pingers," French armed forces spokesman Christophe Prazuck said Wednesday.
It's a race against time, because the beacons will start to fade 30 days after the May 31 crash. If the boxes are spotted, the Emeraude will work with the mini-sub Nautile, which can descend to the ocean floor and was a key part of the search for the Titanic.
"There are big uncertainties about the accident site, the ocean floor is rugged ... so it's going to be very difficult," Prazuck told France-Info radio. "It's going to be very complicated and we're going to need a lot of luck" to find the black boxes.
The French submarines will be aided by two U.S. underwater audio devices capable of picking up signals even at a depth of 20,000 feet.
U.S. Air Force Col. Willie Berges, commander of the American military forces supporting the search operation, said the first of two U.S. towed pinger locators is being loaded onto a search ship Wednesday in the northern city of Natal.
He said the Dutch ship contracted by French investigators will head out Thursday and arrive in the search area by Sunday.
The listening devices will be slowly towed in a grid pattern while a 10-person team aboard the vessel watches monitors receiving signals from the locators.
Berges said the second ship is expected to arrive at the port city this weekend.
Report: Search for terror links
The French magazine L'Express reported Wednesday that French intelligence services had matched the names of two passengers on board Flight 447 with those of suspects linked to Islamic terrorism. But it noted that the passengers' birthdates were not available, and that it might only be a case of people with similar names. The names themselves weren't reported.
A senior judicial official in France, speaking on condition of anonymity because of the sensitivity of the subject, said he had received no information to back up the claim. French police and British intelligence officials would not comment on the report. But U.S. officials minimized the media report, Newsweek reported.
A spokesman for Brazil's intelligence agency said Wednesday he had no information about any terrorist connectons to Flight 447. He also spoke on condition of anonymity, per department rules.
Brazil's federal police are examining video footage at the boarding gate to help identify the passengers, according to an agency spokeswoman who insisted on anonymity because she was not authorized to discuss the matter. She said the action was meant to help identify remains, not to pursue any suspicions of terrorism.
Recovery of bodies
A total of 41 bodies have been recovered so far from the scene of the crash, about 400 miles northeast of the Fernando de Noronha islands off Brazil's northern coast. The remains are being flown daily to Recife, where investigators hope to identify them and uncover clues into the crash based on the victims' injuries.
Prazuck told Associated Press Television News that a French frigate, the Ventose, had already gathered 130 pieces of debris, big and small. The debris was being cleaned of salt and was to be taken to an undisclosed location for further analysis, he said.
Without key information from the Airbus A330's missing data recorders, investigators have focused on the possibility that external speed monitors — Pitot tubes — iced over and gave false readings to the plane's computers as it flew into thunderstorms.
Airlines around the world have begun replacing Pitot tubes on their aircraft. And the European Aviation Safety Agency, responsible for the certification of Airbus planes, said it was "analyzing data with a view to issuing mandatory corrective action" following reports about the possible malfunctioning of the Pitot tubes. But it also said the A330 and other Airbus aircraft are safe to operate.
'We are aware of issues'
The Pitot monitors had not yet been replaced on the A330 that was destroyed en route from Rio de Janeiro to Paris.
The agency issued a precautionary bulletin Tuesday reminding operators of the correct procedure if speed indications are unreliable or missing.
"We are aware of issues with this in the past, but at no time were they classified as safety-critical," said Daniel Hoeltgen, the agency's spokesman.
An important part of the investigation relies on a burst of 24 automatic messages the plane sent during the last minutes of the flight. The signals showed the plane's autopilot was not on, officials said, but it was not clear if the autopilot had been switched off by the pilots or had stopped working due to conflicting airspeed readings.
The L-shaped metal Pitot tubes jut from the wing or fuselage of a plane, and are usually heated to prevent icing. The pressure of air entering the tubes lets internal sensors measure the speed and angle of flight. A malfunctioning tube could mislead computers controlling the plane to dangerously accelerate or decelerate.
Air France said it began replacing the tubes on its A330 and A340 jets in May after pilots reported several incidents of icing leading to a loss of airspeed data, and that it had already replaced the Pitots in smaller A320 jets after similar problems were reported.
"What we know is that other planes that have experienced incorrect airspeed indications have had the same Pitots. And airplanes with the new Pitot tubes have never had such problems," said Air France pilot Eric Derivry, a spokesman for the SNPL pilots union.
On Tuesday, the airline assured its pilots that none of its A330s or A340s would fly without at least two of the new instruments, and that all Air France A330s and A340s will have all three Pitots replaced by July. Brazil's air force said it is replacing them for the president's jet.
About 70 airlines operate some 600 A330 planes similar to the doomed Air France jet, and the Pitots being replaced are made by France's Thales Group.
Both French and U.S. officials have said they have seen no evidence terrorism was involved in the crash and a spokesman for Brazil's intelligence agency also said Wednesday he had no information about any terrorist connections to Flight 447. He spoke on condition of anonymity, per department rules.
From Germany, more confirmation came Wednesday about rough weather over the Atlantic along the same route as the Air France crash. Lufthansa confirmed a report in Stern magazine that a passenger was injured when a Sao Paulo-to-Frankfurt flight hit turbulence off the Brazilian coast two days before the Air France crash.
"One can generally expect turbulence on this route," Lufthansa spokesman Michael Lamberty said Wednesday.
In an apparently unrelated incident, a smaller model Airbus A320 experienced undisclosed engine trouble shortly after taking off Wednesday from the Canary Islands and was forced to make an emergency landing, Spain's national airport authority AENA said.
The Spanish Iberworld airliner was headed from Las Palmas on the island of Gran Canaria to Oslo, Norway, AENA spokeswoman Karen Martel said from the island. No one was hurt and the plane was in the air about 10 minutes, she told The Associated Press.
The passengers were taken off the plane and the company planned to put them on a different one bound for Oslo at midday, Martel said.