Air France plane crash: race to find black box after debris spotted

• Lightning alone does not explain crash – ministers
• Questions raised about Airbus computer system
Air France debris
The Brazilian defence minister, Nelson Jobim, in Rio de Janeiro shows where a search aircraft found a seat and other debris of the missing Air France flight Photograph: Ari Versiani/AFP/Getty Images

The following correction was printed in the Guardian's Corrections and clarifications column, Monday 8 June 2009

In the article below we said that the A330's "fly-by-wire" system used an air data computer to guide the aircraft. This function is actually performed by the primary flight control (PFC) computers, which draw not only on the air data - altitude, air speed, and so forth - but also on information from a range of other systems.

Brazilian military planes scouring the equatorial Atlantic today found a three mile path of wreckage in the ­Atlantic Ocean confirming that the missing Air France jet carrying 228 people crashed in the sea, the defence minister, Nelson Jobim, said tonight .

He said the discovery "confirms that the plane went down in that area," hundreds of miles from the Brazilian archipelago of Fernando de Noronha.

The announcement came as questions emerged about the track record of the type of aircraft, an Airbus A330, involved.

"There isn't the slightest doubt that the debris is from the Air France plane," Jobim said. He said the strip of wreckage included metallic and nonmetallic pieces, but he did not describe them in detail. No bodies were spotted in the crash of the ­Airbus A330 in which all aboard are believed to have died.

Earlier in the day air force pilots saw white metallic objects, an aeroplane seat, an orange buoy and jet fuel stains in the water roughly 400 miles north of the archipelago in two areas around 35 miles apart, but there were no signs of life. Two commercial ships reached the site to assist in the search and French naval vessels were on their way last night.

The French military said no ­confirmation of the plane's wreckage could be made until debris was recovered and serial numbers assessed. Air France flight 447 from Rio to Paris, carrying 216 passengers and 12 crew, mysteriously disappeared early yesterday in heavy weather without sending any distress signal, four hours after taking off from Rio.

Air France announced a "catastrophe", saying the plane could have been hit by lightning. But French ministers yesterday said lightning alone did not explain the crash, which would be the worst air disaster in Air France's 75-year history. "All scenarios have to be envisaged," the French defence minister, Hervé Morin, said yesterday. "We can't rule out a ­terrorist act since terrorism is the main threat to ­western democracies, but at this time we don't have any element whatsoever indicating that such an act could have caused this accident."

The environment minister, Jean-Louis Borloo, today described "a race against time" to find the wreckage and the plane's black box flight recorder, without which the crash remained "incomprehensible". He warned that the black box would only emit signals for 30 days. But the Atlantic search area between the coasts of Brazil and Africa remains vast and depths range from 3,000 to 6,000 metres, with currents so strong that the box might never be found. Borloo said that in 2004, when a jet crashed off Sharm El Sheikh, Egypt, even with an exact crash point located, it took 15 days to find the flight recorder at a depth of 1,000 metres.

In the case of the Air France flight, the ocean search area is much wider, there is no exact location and depths are ­estimated to be at least 4,000 metres. The jet sent an automatic message reporting lost pressure and electrical faults before it went missing. But the ­mystery persisted tonight as to how a modern plane operated by three experienced pilots could have crashed.

A law firm representing victims of a previous serious incident involving an Airbus A330 warned that the aircraft could be vulnerable to electrical interference.

London-based Stewarts Law is preparing to sue Airbus, the Australian airline Qantas and a computer manufacturer, on behalf of 30 people injured when an A330 suddenly plunged 650 feet in flight last October. Air accident investigators blamed the rapid descent at 37,000ft over Western Australia on a malfunctioning computer system. The A330 is a "fly-by-wire" aeroplane that uses an air data computer to guide the aircraft and, if necessary, amend pilot errors.

The A330 has flown 707 million passengers since its launch 15 years ago and this week's crash was its first fatal incident in active service. But in the Qantas case, the aircraft's main navigational tool, the air data inertial reference unit, started emitting "electronic spikes" and plunged the A330 into a dive after mistakenly calculating that the aircraft was pitching its nose into the air. In fact, the aircraft was flying level.

According to one theory being examined by lawyers, the Airbus computer systems could have been affected by inadvertent interference from a nearby naval communications station. Jim Morris, a senior associate at Stewarts Law, said the Air France crash had again raised fears about the aircraft's susceptibility to electromagnetic interference. "It could be that if the A330 is more vulnerable to electromagnetic interference, it could have caused the pilots to lose control of the aircraft during severe turbulence," he said. He added: "The indications from the aircraft's datalink system are that there was a loss of electrical systems in a very short space of time, which indicates that there was a catastrophic failure."

Morris said concerns remained that the full cause of the incident in Australia, on a flight from Singapore to Perth, had not been found. "They still do not know what went wrong with this unit. It might not be as resilient to electromagnetic interference as it should be."

An Airbus spokesman said: "An investigation has just started and it is premature to add to any speculation. We are supporting the investigation.

"There is no information to infer that there is any similarity between what happened in Australia and this case. The A330 has an extremely good safety record and this is the first accident on a commercially operated A330."

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