The causes are independent of the plane
IMHO The causes are :
1 The decision of the PF to climb, yet the PNF has told him the temp. was to high;
2 The decision of the PF to re take control from the PNF without annoucement and to climb again yet the PNF has urged him to nose down.
These two decisions of the PF are not a reaction to any information from the plane.
They came from his will and only his will.
The first decision leads directly and logically to a stall;
The latter decision prevented the PNF from recovering the plane.
None of these decision should have come from a Professional Pilot.
These decision had nothing to do with training nor CRM, design etc.
Furthermore, the Captain had a nasty feeling proved by his odd question : "Do you have your licence ?" to somebody that had made the journey with him from Paris.
I really think that it should be investigated to understand in which psychological or physical conditions he was.
I believe that the very short time between the entering of the Captain and the level 100, barely allowed him the time to understand that the PF was climbing against all skills. When this was established, then the PNF could took the control again under the Capt. authority. But it was to late.
I believe that tço many people here and in the press don't make the distinction between the period before teh PF re take control of the plane and the short sequence after.
The BEA should have divided the time around this KEY action:
- Because the PNF needed the authority of the Capt to take control except if he were Rambo.
- Because when the Capt. enters, he doesn't see the end of the stall caused by the first decision of the PF. He lives a NEW sequence just after the PF had RE taken the control and that he climbed again, entering in a new stall.
Too short for the Capt to understand.