When I Was Young

Posted: 23 June 2009 1644 hrs

Debris of the Air France aircraft lost in midflight over the Atlantic Ocean is seen on board a Brazilian Navy Corvette

PARIS: A French mini-submarine has been launched after a "very weak" signal was detected from the flight recorders of the Air France jetliner that crashed in the Atlantic, Le Monde reported Tuesday.

But the French bureau investigating the crash said the black boxes of Flight 447 had not been found and that research teams "check out any sound" that might lead to them.

The Nautile submersible set out on Monday after French navy vessels detected a "very weak signal" several hundred kilometres off the coast of Brazil, Le Monde reported on its website. No source was quoted in the report.

Owned by Ifremer, the French oceans research institute, the Nautile is capable of operating at a depth of six kilometres (3.7 miles) and was used by research teams who explored the wreck of the Titanic.

"No flight recorders have been located to this day," said a spokeswoman for the BEA aviation investigating bureau.

"This is not the first time that we have heard noise. We check out all of these noises. The research effort continues," she said.

The homing beacons on the devices will only operate for around another week.

"I have no confirmation for the time being" that the flight-data recorders have been found, said Captain Christophe Prazuck, spokesman for the army general staff.

The Air France Airbus A330 carrying 228 people from Rio de Janeiro to Paris came down in the Atlantic on June 1. The cause of the disaster has not been established.

Fifty bodies have been recovered from the crash zone, along with hundreds of pieces of the plane.

The Nautile was taken to the debris zone on board the French maritime research vessel Pourquoi Pas and was to be deployed once the ping from the black boxes was detected.

Other than the Pourquoi Pas, the French nuclear submarine Emeraude and two high-sea vessels equipped with sonars are taking part in the deep-sea search for the vital data and voice recorders of Flight 447.

The boxes - in reality bright orange - would help investigators piece together the final minutes of the ill-fated flight that went down during a storm as it was flying through turbulence.

No distress call was received from the pilots, but there was a series of 24 automated messages sent by the plane in the final minutes of the doomed flight.

French investigators probing the crash have said that the airspeed sensors, or pitot probes, had been feeding inconsistent readings to the cockpit.

Conflicting airspeed data 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.

But the BEA, along with Airbus and Air France, have said there is as yet no firm evidence linking the speed monitors and the crash of the jetliner.

Air France has upgraded all sensors on its long-haul fleet as precautionary measure after protests from pilots.

The crash was the worst in Air France's 75-year history.

- AFP/yb

From ChannelNewsAsia.com; see the source article here.