Barit - again I do not agree - you are also involving the 'dynamics' of a body in this
the mass and dynamic response of each pilot's arms and legs
. A basic PIO is totally pilot induced, and caused by deliberate control inputs which are incorrectly timed/phased, due either to pilot response, aircraft reaction or control damping. The correct 'cure' is not to 'let go' but to 'freeze' the controls until the PIO dampens (normal stability). You and Machin seem to be describing some sort of event whereby a pilot's body is 'flailing around' and moving the controls (I've met pilots like that
). I could, I suppose, envisage a situation in severe turbulence where a pilot was flying with one hand on a yoke stick (unlikely!) and thereby being forced to make aileron inputs through the acceleration forces on the arm, but that is an unlikely event. It would be most unlikely in pitch and yaw. Yours is not a classic PIO and more relevantly neither can I see any way in which the yawing motion of 587 could in any way have induced such rudder application.