LONDON—A tire on the Air France Concorde that crashed outside Paris July 25 probably hit a piece of metal on the runway and burst, the tire debris puncturing at least one fuel tank on the left wing and leading to the crash, investigators said.
While authorities are blaming tire failure for causing the accident, "there was no question over the integrity of the tire prior to the impact with the piece of metal," said Ken Smart, of the U.K.'s Department of the Environment, Transport and the Regions/Air Accidents Investigation Branch.
The determination by French authorities and the possibility of a similar accident because of the aircraft's design prompted the Civil Aviation Authority of the United Kingdom to suspend the certificates of airworthiness for British-registered Concordes "until appropriate measures have been taken to ensure a satisfactory level of safety as far as tire destruction is concerned."
British Airways P.L.C., which operates the Concordes, immediately halted flights of the jets.
French civil aviation authorities took the same action in France. Air France suspended all Concorde operations immediately after the accident.
"The destruction of the tire has caused damage, either directly or indirectly, to the aircraft structure and systems, leading to the crash," said Mr. Smart, who worked closely with French officials investigating the crash. The authorities took this action because "a burst tire alone should never cause the loss of a public transport aircraft," according to Sir Malcolm Field, chairman of the U.K. Civil Aviation Authority.
"The significant new development is the evidence now emerging that the tire burst which occurred was, of itself, the primary cause of this accident," Mr. Field said at an Aug. 16 news conference in London. "At this stage of the inquiry what is uniquely different in this case is that tire debris alone is thought to have led to this catastrophic accident."
Goodyear supplies all tires to the Air France Concorde fleet. British Airway's Concordes are supplied by Dunlop Aircraft Tyre Co., an independent company with no connections to Goodyear or Dunlop. Dunlop Aircraft Tyre originally was part of Dunlop Holdings, but then became part of BTR P.L.C. in the wake of Dunlop's financial troubles in the 1970s. It was spun off to local management three years ago.
Concordes have suffered 70 tire bursts since the jet came into commercial service in 1976. Of these, seven have led to the rupture of a fuel tank, according to Mike Bell, head of design and standards at the CAA.