Concorde report backs crash theory

The crash killed all 109 passengers and crew, along with four people on the ground

PARIS, France -- The official report into the 2000 Concorde crash has confirmed a long-held theory that a piece of debris on the runway sparked a chain of events that caused the tragedy.

The findings are contained in the French air accident investigation branch's final report into the crash, released on Wednesday.

The supersonic jet crashed just minutes after taking off from Charles de Gaulle airport outside Paris on July 25, 2000, killing all 109 passengers and crew, and four people on the ground.

The 400-page report by the Bureau Enquete Accident (BEA) also criticises Air France for deficiencies in maintenance, but says those faults did not cause the crash.

Air France said in a statement that those faults had been corrected.

RESOURCES In-depth: Concorde  A supersonic return   RESOURCES BEA site: The report in full  (in French)

"Although they didn't contribute to the accident, the faults pointed out in the BEA report have been the object of detailed analysis and appropriate corrective measures," the statement says.

The report says the aircraft was doomed, even if its pilots had been able to abort takeoff.

It says an aborted takeoff would have led to a collapse of the landing gear and to the aircraft "blazing up."

The report recommends the installation of flight recorders that log every second, rather than every other second, and video systems in cockpits.

Investigators believe the metal strip that burst Concorde's tyres came from a Continental Airlines DC-10 that took off a short time earlier.

The report says a tire burst after hitting a stray metal strip on the runway

The report recommends that the U.S. Federal Aviation Agency audits maintenance procedures at Continental Airlines.

The Houston-based airline has said in the past that it does not believe one of its aircraft was responsible for the accident, but that it could not comment until the investigation was complete.

The explosion sent rubber debris hurtling toward fuel tanks and prompted a fuel leak and fire that brought the plane down.

The aircraft flew for around a minute at a speed of around 120mph and at an altitude of about 200ft, but was unable to gain height or speed before crashing into a small hotel in the town of Gonesse.

The report said that the performance of the aircraft before it ran over the metallic strip was quite normal.

Concordes have since been fitted with fuel-tank liners of bulletproof Kevlar, a reinforced undercarriage and stronger tires.

The crash led to the grounding of all five remaining Air France Concordes and the seven aircraft in the British Airways fleet.

After modifications to fuel tanks, tyres and wiring, and after a number of test flights, BA and Air France were able to resume Concorde passenger services in November 2001.

The aircraft's new tires, designed by French firm Michelin, passed rigorous tests, including one that revved the wheel faster than 250 mph -- the Concorde's speed at takeoff -- and stabbed it with a titanium blade.

A legal investigation aimed at determining responsibility for the crash is still under way.