Originally Posted by
Running Ridges
Interesting... How does it improve comfort? Automated rudder inputs to counter it?
Exactly.
The ports sense pressure changes between the right and left sides of the vertical stabilizer. This information is read and transferred to the actuator control boxes, which command rudder movements to counteract the effects of wind gusts on the tail of the aircraft.
Is this something relatively new? I worked the 777 for a while (although not since 2002) and I don't recall hearing about the system.
As far as I know, there is no control switch and the only way one might be aware of the system is through some maintenance pages on the CDU, or, of course, the presence of the static ports and transducers in the vertical stabilizer. It is but one small part of the stability augmentation system of the flight control computer system.