Air France plunge-nose up during a stall warning? WTF?

[the330thbg]

PARIS (Reuters) – Pilots wrestled with the controls of an Air France airliner for more than four minutes before it plunged into the Atlantic with its nose up, killing all 228 people on board, French investigators said Friday.

The 2009 emergency began with a stall warning two and a half hours into the Rio-Paris flight and nine minutes after the captain had left the cockpit for a routine rest period.

The Airbus A330 jet climbed to 38,000 feet and then began a dramatic three and a half minute descent, rolling from left to right, with the youngest of three pilots handing control to the second most senior pilot one minute before the crash.

The timeline was described in a note by France's BEA crash investigation authority, which said it was too early to give the causes of the crash ahead of a fuller report in the summer.

"These are so far just observations, not an understanding of the events," BEA director Jean-Paul Troadec told reporters.

The captain returned after "several attempts" to call him back to the cockpit but was not at the controls in the final moments, according to information gleaned from black boxes.

By the time the 58-year-old returned, just over a minute into the emergency, the aircraft was plunging at 10,000 feet a minute with its nose pointing up 15 degrees and at too high an angle compared to the onrushing air to provide lift.

The BEA said the reading of black boxes hauled up from the Atlantic floor earlier this month suggested the crew were not able to determine how fast the plane was flying.

That echoes earlier findings which suggest the pitot tubes or speed sensors on the plane may have become iced up.

It also said that crew mainly responded to stall warnings by attempting to lift the nose of the plane, without elaborating.

Experts say pilots typically push the stick forward to cope with a stall to close the angle with the air and regain lift.

Air France said it would make a statement later Friday.

[CAPFlyer]

Massive icing due to the weather conditions and a deep stall, it's certainly possible. Especially if their air data computer isn't working properly due to icing and they're in IMC and can't tell what the plane is really doing since the instruments aren't reliable. Remember, these pilots are trained to not trust their "butt feeling" in IMC and trust the instruments. When the instruments go bad, what do you do?

Here's the "Official Statement" on what they've found -
http://www.bea.aero/fr/enquetes/vol.af. ... 011.en.pdf

The indications seem to be that they had an air data computer failure due to icing on the pitot and static sensors (as believed previously) and then they stalled and tried to "pull out" of a dive they weren't in, which makes you wonder what the PFD was or wasn't showing because if it was fully failed or indicating incorrectly for some reason, it would explain trying to pull out of a dive due to lack of visual reference but being that they use solid-state gyroscopic devices, I don't know how the two items would go together (icing and failure of the attitude reference instruments). It will be interesting to see the entire report, but it certainly looks like the pilots either suffered from spatial disorientation or they just lost all instruments and had no way of really knowing what the plane was doing until it was too late.

BTW, I think this accidentally got put in the wrong forum.