A mistake made weeks earlier and thousands of miles away by a Continental mechanic in Houston played a crucial role in the crash, the court found.
According to the original ruling, mechanic John Taylor fitted the wrong metal strip on a Continental DC-10. The piece ultimately fell off on the runway in Paris, puncturing the Concorde's tire. The burst tire sent bits of rubber flying, puncturing the fuel tanks, which started the fire that brought down the plane
On Thursday, Judge Michele Luga overturned the 2010 manslaughter conviction of Continental and mechanic John Taylor, saying their mistakes didn't make them criminally responsible for the deaths.
Even if Taylor knew that the metal strip could become detached, "he could never have imagined a scenario where this simple titanium blade could cause such a disaster," Luga said in court.
Part of the problem was that the Concorde's design left it vulnerable to shock, according to judicial investigators who said officials had known about the problem for more than 20 years. The lower court ruled that though French officials had missed opportunities to improve the Concorde over the years, they could "be accused of no serious misconduct."
Outside the courtroom, Continental Airlines lawyer Olivier Metzner called the decision "historic" and finally put an end "to 12 years of wrongful accusations" against Continental.
"What caused the crash was a plane that shouldn't have been flying," Metzner said of the Concorde, which he claimed was only being kept in service for "economic and symbolic reasons."
Crash victims' families, however, expressed disappointment with the ruling.
Stephane Gicquel, head of a group of victims' families, said Thursday's ruling left them with "a sense of powerlessness."
"The court says the plane shouldn't have flown. It did fly, but no conclusion is drawn," he said.
Attempts to reach Taylor for comment were unsuccessful.
The French court that convicted Continental and the mechanic in 2010 for the crash imposed about $2.7 million in damages and fines on the carrier. The appeals court upheld Continental's civil responsibility and ordered it to pay Air France $1.3 million in damages and interests.
Parties including Air France and Continental compensated the families of most victims years ago, so financial claims were not the trial's focus the main goal was to assign responsibility. In France, unlike in many other countries, plane crashes routinely lead to trials to assign criminal responsibility cases that often drag on for years.
"This was a tragic accident and we support the court's decision that Continental did not bear fault," Megan McCarthy, a spokeswoman for Chicago-based United Continental Holdings Inc., said in a written statement. Continental merged with United in 2010.
The Flight Safety Foundation, an organization that monitors aviation safety, applauded the decision.
"We're very pleased that courts are recognizing that professional human error does not amount to criminal conduct, even where it can lead to catastrophic consequences," said Kenneth Quinn, general counsel for the FSF, based in Alexandria, VA.
At the time it was launched, the Concorde supersonic jet was the height of luxury, flying between New York and the European capitals of London and Paris in less than four hours, instead of a standard flight of over seven hours. Flying west, British Airways boasted, the flight's well-heeled travelers could effectively arrive at their destinations before they left.
The Concorde "was the culmination of a belief in the aviation industry that aircraft would always get faster," said Jeremy Kinney, curator in the Smithsonian Institution's aeronautics division in Washington, D.C. "It was the ultimate fast airplane."
Twenty of the aircraft were built and 14 entered commercial operation, Kinney said.
In the years it took French judicial investigators to work their way to trial, amassing 80,000 pages of court documents, the Concordes were revamped, retired and finally sent to museums.
The Concorde wasn't the first supersonic jet to crash in Paris. The Soviet Union's equivalent, the Tupolev 144, made its debut in December 1968, just days before the first flight of the Concorde. They were mothballed after one crashed at the 1973 Paris Air Show.