Concorde Crash Raises Safety Questions: Experts

July 30 -- Concorde supersonic jets had at least a dozen blown tire incidents before the crash of an Air France Concorde earlier this week, according to safety reports obtained by ABCNEWS.com from U.S. aviation agencies and accounts by British Airways.

In light of the fatal crash, those incidents raise questions about the design of the world’s only supersonic commercial jet, experts say.

Evidence released Friday by French authorities suggests a tire blowout during takeoff of the Air France Concorde at Paris’ Charles de Gaulle airport initiated a sequence of events that led to the crash Tuesday, killing all 109 people aboard, and four more on the ground.

Debris from a blown tire can rupture fuel tanks and fuel lines and be sucked into engines, which are uniquely located above the open landing gear on a Concorde.

French authorities said Friday they believe one tire and possibly two burst as the Concorde was accelerating down the runway.

In examining the evidence so far, investigators also have determined that the No. 2 engine, located near the tire blowout, failed early in the flight. And as a fire raged from the wing in the vicinity of No. 2, a second engine housed next to No. 2 also failed just before the plane crashed into a hotel.

But investigators have not yet announced a conclusion on what was ultimately responsible for the crash. In addition to looking at tire debris as a possible cause, they are probing the possibility that improper engine maintenance or a faulty part could have brought down the plane. Following this weeks’ crash, Air France grounded its fleet of Concordes, but British Airways Concordes continue to fly.

Design Concerns

Since entering service with British Airways and Air France in 1976, the Concorde has been revered as one of the safest jets in service. Until this week it was never involved in a fatal accident.

But a ruptured tire on a Concorde can be especially serious, experts say, because of the aircraft’s unique design, which allows it to cruise at twice the speed of sound.