FERNANDO DE NORONHA, Brazil - An airplane seat, a fuel slick and pieces of white debris scattered over several miles of ocean marked the site in the mid-Atlantic yesterday where Air France Flight 447 plunged to its destruction, Brazil's defense minister said.

Brazilian military pilots spotted the wreckage 400 miles northeast of these islands off Brazil's coast. The plane carrying 228 people vanished Sunday about four hours into its flight from Rio de Janeiro to Paris.

"I can confirm that the five kilometers of debris are those of the Air France plane," Defense Minister Nelson Jobim told reporters at a news conference in Rio. He said no bodies had been found and there was no sign of life.

The effort to recover the debris and locate the all-important black box recorders, which emit signals for 30 days, is expected to be exceedingly challenging.

"We are in a race against the clock in extremely difficult weather conditions," French Prime Minister Francois Fillon told lawmakers in parliament yesterday.

The debris was floating in two areas about 35 miles apart, said Air Force spokesman Jorge Amaral. The area is not far off the flight path of Flight 447.

The cause of the crash will not be known until the black boxes are recovered, which could take days or weeks.

But weather and aviation experts are focusing on the possibility of a collision with a brutal storm that sent winds of 100 mph straight into the airliner's path.

"The airplane was flying at 500 mph northeast and the air is coming at them at 100 mph," said AccuWeather.com expert senior meteorologist Henry Margusity. "That probably started the process that ended up in some catastrophic failure of the airplane."

But several veteran pilots of big airliners said it was extremely unlikely that Flight 447 intended to punch through a killer storm.

The same violent weather that might have led to the crash also could impede recovery efforts.

"Anyone who is going there to try to salvage this airplane within the next couple of months will have to deal with these big thunderstorms coming through on an almost daily basis," Margusity said. "You're talking about a monumental salvage effort."

Even at great underwater pressure, the black boxes "can survive indefinitely almost. They're very rugged and sophisticated, virtually indestructible," said Bill Voss, president and chief executive of the Flight Safety Foundation in Alexandria, Va.

"I would expect they'll dedicate the rather substantial resources of the French navy to this," Voss added.

"I've got to figure this will go quickly. I'm hoping they'll have stuff up in a month, if not just a few weeks."

Rescuers were still scanning a vast sweep of ocean.

If no survivors are found, it would be the world's worst civil- aviation disaster since the November 2001 crash of an American Airlines jetliner in Queens, N.Y., that killed 265 people. *