The Concorde was designed just when we started counting on the Space Age to really happen. But it's also an expression of Europe's resentment of the United States. Want to learn more?

The weather was not a concern for this accident which killed all 109 passengers, as well as four guests at the hotel the plane struck. The plane was totally destroyed by a huge fire due to the full tanks of fuel it carried for its from Charles de Gaulle airport in Paris en route to John F. Kennedy airport in New York.

Repairing and maintaining the Concorde is an ongoing challenge, Brancatelli said, as there are no second-generation Concordes.

Only 16 Concorde aircraft have been built. Twelve are operational today after Tuesday's accident. The price of each Concorde is estimated to be $42 million.

"You know how you repair a Concorde after a part breaks? You cannibalize it off an existing Concorde," Brancatelli said.

British Airways and Air France, the two carriers that operate Concordes, keep some planes on the ground to use for parts. "It's like keeping a hot rod alive," Brancatelli said. There has never been a plan to replace Concordes because they are not commercially viable.

For every hour of flight, the Concorde needs eight hours of maintenance on the ground, four times more than for an Airbus aircraft. With room for only 128 passengers, it was too small and too costly to make bundles of money.

"The Concorde is an industrial Vietnam", French Congressman Jean-Jacques Servan Schreiber declared in 1971, speaking of the huge investment to develop it.

Air France and British Airways have said recently they plan to keep their Concorde fleets in operation for another 15 to 20 years.

Cause remains unknown

Observers of the Tuesday crash reported that two engines on the plane's left side were afire but that fails to fully explain the disaster, one expert said.

"An engine fire on one engine is far from enough to lose a Concorde," said Gilles Patri, an aerospace writer who has covered the Concorde's development. "The three other engines can easily compensate during takeoff, and even with two engines down, Concorde can fly back to its initial starting point."

"Something else must have happened to this Concorde," Patri said. The plane was upgraded recently and equipped to put out engine fires automatically with a solid, nonflammable product.

Although the fire was extremely violent, the aircraft's two black boxes were recovered, said Didier Bonnel, official spokesman for the BEA (Bureau Enquetes Accidents), the French government body in charge of air crash investigations.

The black boxes, actually orange in color, record the crew's voices and flight data. With the help of hundreds of police and safety forces, four BEA investigators were working at the crash site Tuesday night.

The Concorde was on a charter flight with an experienced Air France crew. The price of flying the Concorde is estimated to be $24,285 an hour.

The first studies of Concorde started in 1956. In 1962, France and Great Britain signed an agreement to initiate the Concorde program.

Staff Writer Maia Weinstock contributed to this report.