'You have flames, you have flames behind you'

Concorde disaster: For the crew, the flight started as just another routine stint at work. Seconds later, the cockpit was full of alarms on alert

For Christian Marty, the pilot of Air France Concorde flight 4590, it had already been a busy day, even before he asked for take-off clearance from Charles De Gaulle airport at 4.41pm on Tuesday 25 July.

For Christian Marty, the pilot of Air France Concorde flight 4590, it had already been a busy day, even before he asked for take-off clearance from Charles De Gaulle airport at 4.41pm on Tuesday 25 July.

When the Concorde, one of six run by Air France, had arrived in Paris from New York on the Monday, the left wing's number two engine's reverse thruster - a clamshell-like pair of cowlings that close over the jet exhaust to redirect the forward thrust to slow it down on landing - was not working.

No spare part was available directly, and the manufacturers, Rolls-Royce of Britain, and Snecma of France, said the plane could safely fly in that condition. But Cpt Marty ordered the replacement. The part was taken from a back-up Concorde that Air France had to hand and installed in a 30-minute procedure during the afternoon.

The Concorde had a long history with Air France, which was the only airline apart from British Airways to operate the supersonic aircraft, which once over the Atlantic can travel at twice the speed of sound. It had had no fatal accidents since going in to service 24 years before. But there had been scares: the day before, microscopic cracks had been found in the wings of some British Airways Concordes, and the company had considered grounding the plane. But instead it determined to keep watch on them and continue flying.

The conditions on runway 26 were good that day: there was hardly any wind and the air traffic controller authorised take-off at 4.42.

"Is everyone ready?" asked Cpt Marty. The co-pilot and mechanic said they were. The huge delta-winged aircraft accelerated down the runway. The passengers - a group of German tourists who were paying for a premium flight to New York, to be followed by a Caribbean cruise - would surely have felt elation at the prospect of the exclusive journey, which normally costs more than £6,000.

To the crew, it was another day at the office as Cpt Marty lifted the nose and they left the ground, soon reaching the point known as "V1", at which the plane must complete its take-off because there is not enough runway left to land again.

Seconds later, the day at the office turned to disaster. "Concorde zero ... 4590, you have flames ... you have flames behind you," said ground control. The aircraft was now less than 30 seconds from destruction, and the apparent calm of the crew in the transcript belies the terror that must have grown in their minds.

They performed the procedures to raise the undercarriage (impossible because the fire had destroyed the controls), and then to stop the fires in one, then two engines on the left wing.

In the following seconds, all efforts had to be concentrated on simply keeping the nose of the plane up. But this also failed because with the two left engines ablaze, there was no chance at all that the plane might remain aloft.

The cockpit had been filled with a cacophony of alarms - fire, airspeed and undercarriage. Despite the valiant efforts of Cpt Marty, the huge aircraft crashed on to a nearby hotel at Gonesse.

Many of its residents are convinced that Cpt Marty managed to avoid landing on more populated parts of the town. Even so, four people on the ground also died as a result of the crash.

The disaster was triggered by a piece of metal, whose origin remains unclear. It was about 16 inches long and was lying on the runway, unnoticed by the crew. As the Goodyear tyre ran over it, the metal tore a 12-inch gash in the pressurised tyre, and the rubber from that then pierced the fuel tank in the wing above, which ultimately led to the fire .

Fire crews, already alerted as the plane had taken off, rushed to the scene but were unable to save anyone. Traffic cones were used to mark the positions where bodies came to rest at the scene, a grim pinpointing of an event that seemed to draw a curtain on an era of technological optimism.

British Airways briefly suspended its Concorde flights, but started them again within two days. Air France grounded its entire fleet, now reduced to five. But BA also halted flights on 16 August when the French and British Air Accident boards decided that the tyre puncture had been the direct cause of the whole catastrophe and that it was impossible to guarantee such an event would not happen again until Concorde is modified. How, and at what cost, has yet to be determined.

Paul-Louis Arslanian, the chief investigator for the French accident agency, stressed last month the speed with which the burst tyre crippled the Concorde.

"What is important ... is the serious destruction within several seconds," Mr Arslanian said. "We had proof that you can have a catastrophic chain of events in a very short lapse of time and we saw that the crew could do nothing," he added.

For Cpt Christian Marty, there was simply no time remaining to attempt to save an appalling situation, which had started out as just another day, from turning into disaster.