First, the autopilot disengaged, and then an alarm warned passengers that all hell was breaking loose on doomed Air France Flight 447.

PHOTOS: Air France Flight 447 Search & Rescue

It was shortly after 11 p.m. Sunday Brazil time and the Airbus 330-200 was flying through terrifying black clouds packing updraft winds of 100 mph.

All planes — even military ones — are at risk when buffeted by winds of such ferocity, experts say. Flight 447 was no exception.

Within a span of 14 minutes, its electrical systems and cabin pressure failed, and the plane broke apart and began its dive of death into the Atlantic Ocean with 228 people on board.

What caused the tragedy of Flight 447 is still a mystery. Its black boxes may never be recovered.

If so, investigators will have to rely on the last messages transmitted by the stricken aircraft. A chronology of those messages was published yesterday by the Brazilian O Estado de S. Paulo newspaper and confirmed by an airline-industry official.

These are the grim facts of the 14 minutes of death:

At 11 p.m. (10 p.m. EDT), pilot Marc Dubois sent a manual signal saying he was flying through an area of “CBs” — black, electrically charged cumulonimbus clouds that carry violent winds and lightning.

Satellite data show that the thunderheads — towering up to 50,000 feet — were sending 100 mph updrafts into the jet’s flight path.

“Such an updraft would lead to severe turbulence for any aircraft,” AccuWeather said.

“In addition, the storms were towering up to 50,000 feet and would have been producing lightning. The Air France plane would have encountered these stormy conditions, which could have resulted in either some structural failure or electrical failure.”

At 11:10 p.m., a cascade of horrific problems began.

Automatic messages relayed by the jetliner indicate the autopilot had disengaged, suggesting Dubois and his two co-pilots were trying to thread their way through the dangerous clouds manually.

A key computer system had switched to alternative power and controls needed to keep the plane stable had been damaged.

An alarm sounded, indicating the deterioration of flight systems.

At 11:13 p.m., more automatic messages reported the failure of systems to monitor air speed, altitude and direction. Control of the main flight computer and wing spoilers also failed.

The last automatic message, at 11:14 p.m., indicated complete electrical failure and a massive loss of cabin pressure — catastrophic events, indicating that the plane was breaking apart and plunging toward the ocean.

“This clearly looks like the story of the airplane coming apart,” the airline-industry official said.

Bill Voss, president and CEO of the Flight Safety Foundation in Alexandria, Va., said the fact that areas of wreckage were found miles apart in the Atlantic indicates the plane broke apart in midair.

“I doubt it would be that large an area if it had hit intact,” he said.

Voss said he didn’t know if lightning, turbulence or a combination of the two caused the crash. But he said, “Any aircraft, even a military one, is a great risk in weather like that.”

He said that whatever occurred happened “very quickly.”

“The weather became very violent,” he said. “Either there was an error or someone ran out of options.”

Joe Mazzone, a retired Delta Air Lines pilot, said captains often use their radar to weave through thunderstorms — which appear as red blotches — but in such a volatile region, storms can converge suddenly around you, leaving a pilot nowhere to go but through it.

“You’re penetrating where you think you’ve got a hole, and you get in there, and you basically now see that it’s red all around you, so you’re committed now,” Mazzone said.

Perhaps no one will ever know how passengers reacted in those fatal 14 minutes — whether they screamed, grabbed for the oxygen masks or sat in silent prayer.

But once the cabin pressure failed, they would have been unconscious in half a minute, Voss and other experts said.

“It would have been as quick as the moment when one falls asleep,” Dr. Philippe Juvin, head of emergencies at Beaujon Hospital west of Paris, told the French newspaper Le Monde.

The details of Flight 447’s last moments emerged as military planes located more debris from the jet. But waves and heavy winds slowed the recovery effort and delayed the arrival of crucial deep-water submersibles.

Search vessels from several nations pushed toward the floating debris, including a 23-foot chunk of plane and a 12-mile- long oil slick that Brazilian pilots spotted from the air.

The new wreckage was discovered about 55 miles south of where searchers Tuesday found debris.

The Brazilian defense minister, Nelson Jobim, said the existence of the fuel probably ruled out a fire or explosion.

“If we have oil stains, it means it wasn’t burned,” he said.

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 deep as 22,950 feet.

Brazilian divers are expected to arrive today. Any possible recovery of black boxes will have to wait for the arrival next week of a French research ship with remote-controlled submersibles.

andy.geller@nypost.com