Military planes located new debris from Air France Flight 447 while investigators focused on a nightmarish ordeal 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 on 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.
The pilot sent a manual signal at 11pm 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 has shown that towering thunderheads were sending 100 mph 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 11.14pm, signalled 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.”
Air France spokesman Nicolas Petteau referred questions about the messages to the French accident investigation agency, BEA, whose spokesman Martine Del Bono said the agency won’t comment.
Brazil’s Defence Minister Nelson Jobim also declined to comment, saying that the accident “investigation is being done by France; Brazil’s only responsibility is to find and pick up the pieces”.
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.
A US 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.
Mr Jobim said debris discovered so far was spread over a wide area, with some 140 miles separating pieces of wreckage they 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, Air Force spokesman Colonel Jorge Amaral said.
“Oil stains on the water might exclude the possibility of an explosion, because there was no fire,” Mr Jobim told reporters.
The new debris was discovered about 55 miles south of where searchers a day earlier found an airplane seat, a fuel slick, an orange life vest and pieces of white debris.
The original debris was found roughly 400 miles northeast of the Fernando de Noronha islands off Brazil’s northern coast, an area where the ocean floor drops as low as 22,950 feet below sea level.
Brazil lacks the equipment needed to reach the ocean floor. If the black boxes are at the bottom of the sea, their recovery will have to wait for the arrival early next week of a French research ship with remotely controlled submersibles that can explore as deeply as 19,600 feet.
The sturdy black boxes – voice and data recorders – are built to give off signals for at least 30 days, even underwater, and could keep their contents indefinitely.
But the head of France’s accident investigation agency, Paul-Louis Arslanian, said in Paris that he is “not optimistic” about recovering the recorders – and that investigators should be prepared to continue the probe without them.
“It is not only deep, it is also mountainous,” he said. “We might find ourselves blocked at some point by the lack of material elements.”
Mr Arslanian said investigators didn’t have enough information to determine whether the plane broke up in the air or upon impact with the sea, and that in the absence of black box data, they are studying maintenance and other records.
“For the moment, there is no sign that would lead us to believe that the aircraft had a problem before it took off,” Mr Arslanian said.
If no survivors are found, it would be the deadliest crash in Air France’s history, and the world’s worst civil aviation disaster since the November 2001 crash of an American Airlines jetliner in the New York City borough of Queens that killed 265 people.