FERNANDO DE NORONHA, Brazil - Military planes located more debris from Air France Flight 447 yesterday, while investigators focused on a nightmarish scenario in which the jetliner broke up over the Atlantic as it flew through a violent storm.

Heavy weather delayed until next week the arrival of deep-water submersibles considered key to finding the black box voice and data recorders that will help answer the question of what happened to the airliner, which disappeared Sunday with 228 people on board.

But even with the equipment, the lead French investigator questioned whether the recorders would ever be found in such a deep and rugged part of the ocean.

As the first Brazilian military ships neared the search area, investigators were relying heavily on the plane's automated messages to help reconstruct what happened to the jet as it flew through towering thunderstorms. They detail a series of failures that end with its systems shutting down, suggesting the plane broke apart in the sky, according to an aviation-industry official with knowledge of the investigation, who spoke on condition of anonymity because he was not authorized to discuss the crash.

The pilot sent a manual signal at 11 p.m. local time saying he was flying through an area of "CBs" - black, electrically charged cumulonimbus clouds that come with violent winds and lightning. Satellite data have shown that towering thunderheads were sending 100-m.p.h. updraft winds into the jet's flight path at the time.

Ten minutes later, a cascade of problems began: Automatic messages indicate the autopilot had disengaged, a key computer system switched to alternative power, and controls needed to keep the plane stable had been damaged. An alarm sounded indicating the deterioration of flight systems.

Three minutes after that, more automatic messages reported the failure of systems to monitor air speed, altitude, and direction. Control of the main flight computer and wing spoilers failed as well.

The last automatic message, at 11:14 p.m., signaled loss of cabin pressure and complete electrical failure - catastrophic events in a plane that was likely already plunging toward the ocean.

"This clearly looks like the story of the airplane coming apart," the airline-industry official said. "We just don't know why it did, but that is what the investigation will show."

Other experts agreed that the automatic reports of system failures on the plane strongly suggest it broke up in the air, perhaps due to fierce thunderstorms, turbulence, lightning, or a catastrophic combination of events.

"These are telling us the story of the crash," said Bill Voss, president and CEO of the Flight Safety Foundation in Alexandria, Va. "They are not explaining what happened to cause the crash. This is the documentation of the seconds when control was lost and the aircraft started to break up in the air."

Voss stressed that the messages alone were not enough to understand why the Air France jet went down, noting that the black boxes would have far more information to help determine the cause.

One fear - terrorism - was dismissed yesterday by all three countries involved in the search and recovery effort. France's defense minister and the Pentagon said there were no signs that terrorism was involved.

A U.S. Navy P-3C Orion surveillance plane, a French AWACS radar plane, and two other French military planes joined Brazil's air force in trying to spot debris and narrow the search zone.

Brazilian Defense Minister Nelson Jobim said debris discovered so far was spread over a wide area, with about 140 miles separating pieces of wreckage searchers have spotted.

The floating debris includes a 23-foot chunk of plane and a 12-mile-long oil slick, but pilots have spotted no signs of survivors, an air force spokesman, Col. Jorge Amaral, said.

"Oil stains on the water might exclude the possibility of an explosion, because there was no fire," Jobim said yesterday.