Originally posted by Machinbird
The definitions of PIO have evolved over time and encompass a broader spectrum of oscillations.
The modern definition of PIO is Pilot Involved Oscillation and gets away from blame and fault concepts. Without the pilot in the control loop, the oscillation does not occur.
Which confirms my fear that I am thoroughly out of date on some things!
To him, it must have seemed that he was a little too late with his control input, so he accelerated his control inputs, i.e. went faster. I think that you can see this pattern in aircraft behavior and in control behavior if you look at the timing on a cycle to cycle basis.
That is my point really. Control of the oscillations is all about getting the phasing of the control inputs right. Roll rate is 90 deg out of phase with roll acceleration, so if he was accustomed to a roll rate response to stick he could have been very confused by an aircraft that took a little longer to develop the response he was anticipating. That would be entirely consistent with your remarks