Originally Posted by AC-25-11A
In particular, display system lag (including the sensor) for attitude which does not exceed a first order equivalent time constant of 100 milliseconds for airplanes with conventional control system response is generally acceptable.
Thank you OK465, that is useful data.
By itself, the display lag should not enable an oscillation. About what I was expecting.
Originally Posted by OK465
(I think if you grabbed hold of an Airbus SS you'd be somewhat underwhelmed by the roll responsiveness in roll direct, even at altitude. But indeed no doubt this can be a relative thing depending on background and training.)
I would personally expect somewhat ponderous response compared with the tactical aircraft and smaller transports that I've flown.
In Bonin's case, he had insufficient time to appreciate he was no longer in Normal law when he made his initial roll correction. I can see how an assumption of being in Normal law could set him up for a roll PIO in Alt 2 law. (His initial input would be 'open loop'.)
Just because an aircraft is quite large is no reason to discount PIO. They PIO quite nicely judging from the record, particularly along the roll axis.