Machinbird wrote:
The BEA note seems to indicate that the PF was making frequent large control inputs.
Large control inputs (high gain activity for the control theorists) are contrary to this Pilots training. Something scared the Bejesus out of him to get this type of behavior.
The only thing that makes sense is that he encountered lateral PIO (And PIO is definitely an aircraft problem). Another name for PIO is pilot in the loop oscillation.
I believe machinbird may have hit on something. This is an area that may eventually provide an explanation and enlightenment for what some people currently see as inexplicable behaviour by the PF. And, though Machinbird's scenario (PIO) is quite possible, it certainly isn't the only possible scenario that involves lateral control issues once the aircraft was in Alt2.