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article imageConcorde crash remains unresolved 10 years later

By Michael Cosgrove     Jul 25, 2010 in Travel
Paris - Today marks the tenth commemoration of the Concorde crash near Paris which killed 113 people. The ensuing investigation and trial have blamed Continental Airlines for the crash, but several crucial questions remain unanswered.
Air France Flight 4590 took off on July 25 2000 from Charles de Gaulle airport in Paris bound for John F. Kennedy airport in New York. The flight lasted just under two minutes before the plane banked and rolled over until it was almost upside down before crashing onto a hotel in Gonesse, near Paris. All 109 passengers and crew were killed, as were four people on the ground. The majority of the dead were German tourists.
Photos and a video taken just after take-off showed that the plane was trailing an enormous ball of flame behind its left wing as it struggled to gain height.
The subsequent investigation was carried out by French air accident investigating authority the BEA, and its conclusions were published in 2004. The BEA had concluded that the accident was of “single cause” origin, a rare event in itself as most airliner crashes are the result of several concomitant factors.
The BEA said that the accident was caused by a short titanium strip left on the runway by a Continental plane which had taken off four minutes earlier. The strip was said to have burst a tire on the port (left) side of the aircraft, which led to pieces of rubber being flung up onto the underside of the wing, rupturing a fuel tank and leading to a massive leak of fuel which ran backwards towards an engine outlet and ignited. The plane became uncontrollable as a result and crashed.
French authorities began a criminal investigation into Continental in 2005 and the trial of those considered to be responsible began in February of this year. The Prosecutor has demanded a €175,000 ($225,000) fine for the airline and two-year suspended jail sentences for two of its employees. Others were also charged and the verdict is scheduled for December 8.
The trial was marked however by several major disagreements on issues which Continental and many observers and aviation industry experts have raised to suggest that the crash did not happen as BEA and the prosecution allege.
First of all, critics say that the trial did not address the reasons which had led Air France to be heavily criticized by a 1981 report sent to them by the American National Transportation Safety board (NTSB) which accused them of lax procedures and a lack of action being taken to remedy the causes of four potentially catastrophic tire bursts which had occurred during Concorde take-offs; The problem and the reasons for it were well-known and there had been many other documented tire bursts. This problem had already persuaded British airways, the other airline running Concordes, to take measures designed to help minimize the risks.
Continental has always denied the charges against it and says that the aircraft was already on fire when its wheels hit the titanium strip, and that around 20 first-hand witnesses had confirmed that the plane seemed to be on fire immediately after it began its take-off roll. Continental says it is being used as a scapegoat by French authorities. Some of those witnesses were questioned by the prosecution, who said they were not well-placed enough to be sure.
There has also been bitter disagreement over the possible role played by a combination of the plane’s take-off weight, its speed, and prevailing wind conditions.
An in-depth report by the Guardian which explains the doubts being expressed about the official version claims that at the moment the plane took off, its speed was 188 knots, which is 11 knots below the plane’s recommended take-off speed (VR).
An influencing factor on what happened next would be the plane’s weight, which is widely believed to have been a tonne over the plane’s safe operating limit. This is said to be due to excess baggage and a miscalculation of how much fuel would be burnt off during taxi and wait time.
Finally, the plane’s cockpit voice recorder (CVR) shows that the crew did not react to all the elements contained in a control tower message at 14:42:17 mins informing them of runway information as well as a weather update saying that instead of there being no wind on the runway, there was now an eight knot tailwind.
These factors, if the pilots had been aware of all of them, should normally have led them to recalculate their take-off parameters, which would have meant restarting the take-off sequence. This procedure was not uncommon for Concorde crews.
As it was, the plane began its take-off roll and took off in what are believed to be highly dangerous conditions. The damaged engine and ensuing engine shutdown meant the plane lost even more speed and, according to many observers, became mathematically unflyable.
Another reason which may have contributed to the crash concerns the plane’s maintenance. Air France itself admits that its maintenance staff had not replaced or renewed a vital component of the plane’s left-side landing gear, the ‘spacer,’ after routine maintenance carried out a few days before the crash. It was found in an Air France workshop after the crash.
A Concorde undercarriage assembly consists of two sets of wheels, thus two wheel axles. A spacer is an important part of the assembly which keeps the wheels correctly aligned to each other. If the wheel units are misaligned, friction and drag are caused by the wheels being out of sync and the plane cannot accelerate correctly.
Some aviation experts contend that once the tire burst as a result of the misalignment friction, the excessive resulting change in the weight distribution of the undercarriage caused by the absence of the spacer made the plane veer left, forcing the pilot to take off earlier than he would have done in normal circumstances. Tire marks left on the runway seem to support this reasoning, which the BEA and prosecution have dismissed.
Meanwhile, and far from the disputes and the offices of Continental, Air France and the BEA, the residents of the suburban village of Gonesse are attending a memorial ceremony today for the victims of the crash. The village Mayor will give a short commemorative speech after wreath-laying and a minute’s silence before the sober glass statue with the metal outline of a Concorde embedded within it which stands next to the accident site.
The land itself, which was put up for auction in January, was cleared long ago of the debris from the disaster and now stands empty and deserted because, despite its giveaway price, no-one has bought it.
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