This whole "pilot error" discussion puts me in mind of the deceptive term "pilot induced oscillation" which is actually an airframe problem. PIO is often known as Pilot in the Loop Oscillation or also Aircraft Pilot Coupling, but the key point is that it is more an aircraft design problem-not so much a pilot technique issue.
I can already see that the AF447 cockpit was not well designed for pilot situational awareness in the type of flight conditions encountered by the AF447 crew: No direct AOA indications, no old fashioned steam gage altimeter unwinding, no bell or clacker on the trim wheel to draw attention to its motion, too many competing alarm sounds in the cockpit.
Then there are training issues surfacing and also fundamental how do you fly the 'Bus issues that are surfacing.
We are left with three core issues relating to piloting and aircraft systems.
- What did they see on their radar and how did they interpret it?
- Why did they allow the aircraft to climb from Fl 350 to 380?
- Why did they not succeed in recognizing/recovering from the stall?
It is up to BEA to thoroughly examine these issues. These are all very complex issues and it will not be trivial to sort out. The crew was handed a "Pop Quiz" and failed. The reasons for this failure will extend far past the crew.