Originally Posted by ALF
We might identify what physically happened; and with considered judgement it may be possible to identify contributing factors which could have influenced the crew, but without any assurance of proof.
One thing that demonstrably took much of PF's attention during the first 35 seconds after the AP drop was the very significant roll oscillation and the method used by PF to control the oscillation. (He had apparently never seen Alt2 law at altitude.)
If you look at the periodicity of the oscillation, and of the roll control inputs, his control inputs accelerated (in an apparent attempt to
get ahead of the oscillation.) His inputs did not cease although the aircraft momentarily stopped roll oscillating on approximately 3 occasions, and these continued inputs caused a phase shift in the roll oscillation-based upon my analysis. This type of control input indicates formation of a control strategy, and correction of the control strategy. Clearly, a significant portion of his attention was devoted to the early roll control problem.