757 PIO in Roll
Interesting bit of video of the SEATAC approach. A few years ago Boeing completed an (optional) mod for the 757 which introduces a damper into the roll channel flying controls. The damping effect increases as the speed/magnitude of the pilot input increases. Under normal circumstances the damper isn't felt by the pilot.
Boeing decided on this after a number of occurrences when the somewhat sluggish 757 response in roll - especially toward the end of the approach - could result in an over-enthusiatic application of roll command from the pilot, which in turn could lead to a quite high-amplitude PIO.
The video seems quite a nice example of this - and a fair indication that this aircraft operator didn't take up the mod!