Originally Posted by
fab777
FWIW, I have seen PIO routinely, in any heavy aircraft I have flown: A320/330/350, but also B737/777. The problem lies not so much in the flight control laws, but rather in the fact that some pilots will give an order, and then the opposite order without waiting for the aircraft to complete the first order. Any heavy aircraft has inertia and will take some time before executing what you request from it. Be patient…
And we have a winner!
It’s a feedback loop and the general answer is to reduce the gain and increase the time constant if you find yourself in the PIO zone. Some pilots make measured, controlled inputs between periods of inactivity and some seem to flail away with the stick/yoke constantly. It’s like the two different kinds of drivers: one saws at the wheel all the time and the other just makes corrections when needed using a relatively soft grip. There must be some kind of primacy here, so it’s really down to their first flight instructor for not teaching them properly and/or sorting it out before it becomes habitual...