Faulty data misled pilots in '09 Air France crash

Updated at 11:31 a.m. ET

(CBS/AP) LE BOURGET, France - A combination of faulty sensors and mistakes by inadequately trained pilots caused an Air France jet to plunge into the Atlantic Ocean in 2009, killing all 228 people aboard in the airline's deadliest ever crash, French investigators said Thursday.

Investigators are urging better instruction for pilots on flying manually at high altitudes and stricter plane certification rules as a result of a three-year investigation into what happened to Flight 447.

Airbus, manufacturer of the A330 plane, said in a statement that it is working to improve speed sensors known as pitot tubes and making other efforts to avoid future such accidents. Air France stressed the equipment troubles and insisted the pitots "acted in line with the information provided by the cockpit instruments and systems. .... The reading of the various data did not enable them to apply the appropriate action."

But the Bureau for Investigations and Analysis' findings raised broader concerns about training for pilots worldwide flying high-tech planes when confronted with a high-altitude crisis.

The report also could have legal implications: A separate French judicial investigation is still under way, and Air France and Airbus have been handed preliminary manslaughter charges.

The BEA analysis lists a combination of "human and technical factors" behind the crash. The plane flying from Rio de Janeiro to Paris slammed into the sea during a nighttime thunderstorm on June 1, 2009.

Ice crystals that blocked the pitot tubes were the "unleashing event" that set off the plane's troubles, chief investigator Alain Bouillard said. The plane's autopilot shut off and the co-pilots had to fly manually, while a succession of alarms were going off. The captain was on a rest break.

"In this case, the crew was in a state of near-total loss of control," Bouillard said.

Terrifying last minutes of Air France Flight 447

For more than two years a few pieces of debris floating in the Atlantic Ocean were all that was left of Air France Flight 447. The answer to what happened was seemingly lost forever on the ocean floor. But in May 2011, state-of-the-art submarines made a remarkable dive more than two miles below the ocean surface and collected the crucial black box, Mark Strassmann reports.

Expert analysis of the reported cockpit transcripts point to a perfect storm of problems, including stormy weather, aircraft malfunction and pilot error. But some say there was another contributing factor: the very design of the airbus cockpit.

Capt. Chesley "Sully" Sullenberger, CBS News' aviation and safety expert, said the same disaster would have been "much less likely to happen" in a Boeing plane because "the control wheels are large ... obvious. I think it could hardly have been missed."

To help break down and understand what happened on board Air France Flight 447, Sullenberger went into an Airbus simulator. He showed how a pilot goes from neutral to "full nose-up command" in one small movement.

That small movement on the Airbus flight controls -- or side stick -- raises the nose of the plane and instructs it to climb. Pilots rarely perform the maneuver at high altitudes because it can be very dangerous. But that's exactly what one Flight 447 pilot did.

Around 2:05 a.m., the Airbus A330 was flying through a storm system and all three of its speed indicators stopped working. As a result the aircraft's autopilot turned off.

With the captain on break, the two co-pilots were forced to manually fly the plane. The least experienced pilot, 32-year-old Pierre-Cedric Bonin was in the right seat and said, "I have the controls." Co-pilot David Robert was in the left seat and, even though considerably more experienced, he let Bonin fly.

"Theoretically, it was possible to still fly the airplane under those conditions," Sullenberger said.

Although they lost the autopilot and speed indicators, they were flying normally and safely. But then suddenly, and without Robert knowing, Bonin did something almost inexplicable, - he pulled back on his side stick and raised the nose of the plane. That caused the aircraft to fall, and the stall warning to sound.

Over the next four-and-a-half minutes, the stall warning sounded 75 times. But, strangely, neither pilot mentioned it. And unbeknownst to Robert, Bonin kept the nose of the plane up almost the entire time - exactly what he shouldn't have done.

Because of Bonin's actions, the plane attempted to climb but was actually losing altitude. Robert appeared to have no idea the nose was being lifted when he said "what the hell is happening. I don't understand what's happening." If he had known what Bonin was doing, Robert could have conceivably solved the problem very easily at this point.

Sullenberger showed in a simulator why he thinks -- in this situation -- the design of the airplane helped keep Robert in the dark. Sullenberger said, "It's a subtle movement compared to more traditional airplanes."