British Air accident investigators protested about the slowness of the French investigation into the Concorde crash near Paris last year and the "illegal" refusal of French authorities to give them full access to the wreckage and crash scene.
In an annexe to the final official report of the French inquiry, the British Air Accidents Investigation Branch (AAIB) complained that "obstructions" by the French authorities had breached two international agreements.
The AAIB also complained that the ponderousness of the French investigations, due to the separate technical and judicial inquiries, "significantly slowed" the safety modifications that allowed Concorde to resume commercial flights last year.
Both French and British investigators confirmed the findings of interim reports that the crash in July 2000 was caused by the bursting of a tyre on take-off, which damaged a fuel tank. That led to a fire and other damage, which prevented the aircraft from getting properly airborne. But the exact chain of events remained unclear and the British annexe emphasised doubts about how the debris from the burst tyre caused the fuel tank to explode.
There have been suggestions in the British press and elsewhere that the true cause of the accident, which killed 113 people, was the failure of Air France fitters to replace a strut in the aircraft's undercarriage. The final accident report concluded that the missing strut did not contribute to the accident, but this did not "alter the gravity" of Air France's error.
The report also criticised the American airline Continental Airlines. The Concorde tyre burst after running over part of a Continental DC-10's thrust-reverser, which had fallen on to the runway at Charles de Gaulle airport near Paris five minutes before the Concorde took off. The French air crash investigation agency, the Bureau Enquêtes Accidents, recommended independent audits of Air France and Continental maintenance standards.
Concorde was allowed to resume flights last year with reinforced tyres and strengthened fuel tanks. Nothing in the final report or the British annexe calls into question the safety of the modified aircraft.
However, the AAIB did not pull its punches in its criticism of the French authorities and especially of the French judicial authorities, which mounted a separate investigation that is still in progress.
As the co-builder of the Concorde, Britain had a right to take a full part in the investigation under both the Chicago Convention on air safety and an EU directive of November 1994, the AAIB pointed out. But the French investigating magistrates allowed the AAIB only brief inspections of the piece of metal from the Continental DC-10 and the debris from the Concorde fuel tank. They refused to allow the British investigators to examine what remained of the Concorde's instrument panel. They also refused for six weeks to let the expert crash investigators, both French and British, see a crucial photograph of the runway.
All in all, said the AAIB, they "significantly impeded" the rapid examination of all the evidence, causing "significant delays" in necessary decisions on Concorde's future safety.
The British investigators said they "accept the findings as presented" in the French report but would have given "different emphasis" to some of the technical findings about how the fuel tank came to explode.
The French report suggested a small piece of the burst tyre may have penetrated the fuel tank, causing a violent reaction that forced a larger part of the tank cowling to be pushed off from the inside. The British annexe said the small amount of debris found from the fuel tank did not permit such a clear conclusion.Reuse content