Well in case you haven't heard, after almost 2 years, they finally pulled up the voice and flight data recorder for this airplane from 13,000 ' of water . It does appear that as feared at least one of the pitot probes had iced over which caused erroneous air speed indications in the cockpit.
For those of you who don't know, a pitot probe is one of those small pointed things you see at the front of the airplane pointed forward of course. Air enters these pointed probes and enters the air data computer where it is used to compute speed. It is heated to prevent ice build up. Typically on a commercial airliner there are at least 3 of these pitot probes. One may be connected to the captain's instruments, one may be connected to the first officers instruments and another one is connected to standby instruments.
There were 3 pilots on board. The senior pilot on board had left the cockpit about 10 minutes prior to when they started having problems, to get some rest which is typical of long flights of this nature. The junior pilot on board was flying the plane at this point.
The problem started when they began to make a slight turn to avoid some bad weather and reduced power because they were expecting turbulence to increase. Shortly thereafter the autopilot and autothrust systmes disconnected (autopilot controls the attitude of the aircraft and the autothrust system controls the amount of power the engines are putting out.
Shortly there after the jp (junior pilot) tried raising the nose of the aircraft, which was soon followed by a stall warning. A stall is when an airplane loses lift from the wings. It can be caused by flying too slow or with the nose too high in relation to the relative wind. At this point the plane will start falling out of the sky. Usually the response to a stall or stall warning is to lower the nose. This way air speed builds up and you come out of the stall.
I received my pilot's license over thirty years ago, but I haven't flown in years. It's just too expensive a hobby. But one of the most important things they teach you is how to recover from a stall. Like I said the first thing you do is lower the nose.
Apparently the jp kept doing just the opposite, trying to raise the nose. It took about 3 and 1/2 minutes for them to descend. For a brief period he did lower the nose, but it wasn't long enough to break the stall. Then he started raising the nose again. I would think that the other pilot should have had an idea of what was going on and should haved told the pilot who was flying the plane to lower the nose but such apparently was never the case.
In fairness to the pilots, they were flying at night, possibly flying in clouds where in such cases you lose all sight of the horizon. You don't really know which way is up and because some instrument were malfunctioning, they probably didn't know which ones to rely on and which ones to ignore.
But it sounds like an accident that should not have happened. I'm sure a lot of the investigation will focus on AirFrance's pilot training program because at this point in the investigation which is still quite early, it looks likes the pilot flying the plane did the complete opposite of what he should have done.
Airbus will also share some of the blame too. They and AirFrance knew there was a problem with the probes icing up. They had already shipped replacement probes to AirFrance. AF had not yet had time to replace them when this accident happened. But they could have grounded the fleet until they were replaced if they thought it was enough of a safety issue. They didn't and now they'll probably both have to pay dearly for that decision.