A DISTURBING account has emerged yesterday of the last moments aboard the Air France jet that plunged 35,000ft into the Atlantic Ocean last month, killing all 228 people on board, five of them British.
Initial findings in the official investigation were presented yesterday, but the preliminary report by France's civil aviation accident investigation bureau, the BEA, failed to lift the mystery surrounding what caused the Airbus A330-200 to fall out
of the sky as it crossed a severe tropical storm, resulting in the deadliest crash in the history of Air France.
There were no traces of fire or explosives on the 640 pieces of debris from the aircraft recovered so far from the ocean surface, and examination of the metal remains ruled out a mid-air explosion, thereby excluding a terrorist attack.
"Today we are very far from establishing the causes of the accident," said thechief investigator, Alain Bouillard, at a press conference yesterday at BEA headquarters at Le Bourget Airport, north of Paris.
Air France flight 447, en route to Paris from Rio de Janeiro , disappeared in the early hours of 1 June, some 600 miles off the Brazilian mainland, shortly after it entered a highly turbulent tropical storm.
An intensive search by Brazilian and French navy vessels has recovered the remains of 51 victims. These include the 58-year-old pilot Marc Dubois and a Scottish passenger, 52-year-old oil industry vessel master Graham Gardener, from Gourock in Inverclyde.
The black box flight data and cockpit voice recorders have not been found.
However, Mr Bouillard revealed yesterday that it was now certain that the aircraft, carrying 216 passengers and 12 crew members, fell intact from the sky in a high-speed dive that obliterated the fuselage structure on impact with the ocean.
"The plane appears to have hit the water in the direction of its flight, with a strong vertical acceleration," said Mr Bouillard. "The visual examination that we were able to carry out shows that the plane hit with the underbody of the fuselage.
"The aircraft was intact at the moment of impact."
The fact that no life jackets were found deployed meant that there had been no time to alert passengers. Aviation experts speculated that the pilots might have had just moments to try desperately to regain control of the aircraft, which its angle of impact suggested they were trying to do.
During the final four minutes of the flight, a series of automatic data readings transmitted by the aircraft to an Air France engineering base included what the BEA called several "incoherent" information messages about the jet's speed. A final transmission indicated an electrical failure.
"Between the surface of the water and 35,000ft, we don't know what happened," said Mr Bouillard. "In the absence of the flight recorders, it is extremely difficult to make conclusions."
Among the theories about what caused the accident, including a lightning strike and an exceptional bout of turbulence, increasing evidence has pointed to an inherent fault in the aircraft's three speed sensors, known as Pitot tubes.
More than 30 incidents involving false speed readings have been reported by Airbus pilots, suggesting that these long pipes are prone to becoming blocked by water and ice as aircraft fly through storm zones. Airbus issued a recommendation to change the tubes fitted on A320 aircraft in 2007, and Air France had also begun changing them on its A330 fleet in April of this year.
In the case of AF447, the contradictory speed readings from the speed sensors would have disarmed the automatic pilot, leaving the crew to fly through severe storm turbulence in the dark without a reliable indication of the aircraft's speed and running the risk of stalling.
But Mr Bouillard said yesterday the tubes "were an element but not the cause" of the crash. They were simply "the first link in the chain" of speed data recordings and did not alone make the aircraft uncontrollable.
