Ten minutes later a flurry of automated messages began: The autopilot had disengaged, a key computer system had switched to alternative power. Controls needed to keep the plane stable had been damaged. An alarm sounded indicating flight systems deteriorated.
Three minutes after that, systems needed to monitor air speed, altitude and direction failed, and then the main flight computer and wing spoilers failed as well.
The last message, at 11:14 p.m., reported loss of cabin pressure and complete electrical failure — catastrophic events in a plane that was likely already plunging toward the ocean.
French and Brazilian officials had already announced some details about the messages, but a more complete chronology was published Wednesday by Brazil’s O Estado de S. Paulo newspaper, citing an unidentified Air France source. The Associated Press confirmed the information with an industry official who had knowledge of the investigation. The official spoke on condition of anonymity because he was not authorized to discuss details of the probe.
“This clearly looks like the story of the airplane coming apart,” the official said. “We just don’t know why it did, but that is what the investigation will show.”
The burst of messages — sent automatically by the jetliner’s computer systems — don’t explain what caused the disaster, which destroyed the plane carrying 228 people from Rio de Janeiro to Paris late Sunday night. But the official told the AP that they hold a key to establishing how the airliner went down.
The reasons for the crash will more likely be in “black box” data and cockpit recorders, which may lie in wreckage on the rugged ocean floor.
While military planes and ships struggling through heavy winds found more jet debris Wednesday, the lead French investigator, Paul-Louis Arslanian, said the black boxes might never be found, due to fierce tropical weather and undersea mountains and valleys that drop as much as three miles down.
The last word from the pilot was a manual signal at 11 p.m. local time saying he was entering an area of “CBs” — black, electrically charged cumulonimbus clouds that come with violent winds and lightning.
Satellite data show towering thunderheads were sending 100 mph (160 kph) updraft winds into the jet’s flight path.
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.
Brazilian Defense 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.”
Just what caused these failures is a mystery, although turbulence, violent winds and lightning in the thunderstorms could have contributed to a combination of problems.
“These are telling us the story of the crash. They are not explaining what happened to cause the crash,” said Bill Voss, president and CEO of the Flight Safety Foundation in Alexandria, Va. “This is the documentation of the seconds when control was lost and the aircraft started to break up in air.”
One fear — terrorism — was dismissed Wednesday 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, and Jobim said “that possibility hasn’t even been considered.”
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. The floating debris includes a 23-foot (seven-meter) chunk of plane and a 12-mile-long (20-kilometer-long) oil slick, but pilots have spotted no signs of survivors, 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 told reporters Wednesday.
The new debris was discovered about 55 miles (90 kilometers) 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 (640 kilometers) 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 (7,000 meters) 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 (6,000 meters).
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 Arslanian, who heads France’s accident investigation agency, 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.”
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,” Arslanian said.
He said investigators did not know the exact time of the accident or whether the chief pilot was at the controls when the plane went down. Pilots on long-haul flights often take turns at the controls to remain alert.
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.