SOPS,
In general a SAS (Stability Augmentation System) will damp out one of the aircrafts natural modes of motions in order to bring the flight dynamics to a state that is easier for the pilot to control or allow the autopilot to control the aircaft.
More often it is the phugoid natural mode of motion that needs to damped out in order to allow the autopilot to achieve accurate height hold control.
However the above is just a general decription and I don't know the exact details for the aircraft mentioned in this post.
Last edited by portsharbourflyer; 10th May 2008 at 17:39.