mm43,
Thanks for the graph, it makes it easier to see.
Did you leave out the "roll commands" and "rudder commands" graphs intentionally?
They can help correlate visually the PF actions with the control surface deflections.
The "rudder" commands and control surface deflections on the graphs are confirmed by the CVR transcript's call to "attention with the rudder" by the Captain, in the same time interval with the graphs.
Originally Posted by
mm43
PIO would seem to be the answer, but don't forget that post 2:10:51 the aircraft wasn't within a 'normal' flight envelope.
Worth looking at is the yaw damper, the rudder and the lateral 'g' traces. Once in the 'mush' the aircraft was 'nodding' and rolling/banking in a synchronized manner as well as 'fish tailing'.
Pitch Attitude, Rudder Position and Roll Attitude traces have been overlaid in the second trace in this graphic.