To be stabilized is to be on speed, on profile, fully configured, checklists done, by a certain height, usually 1000 feet. If any of the required elements of a stable approach are not met by the required altitude, then a missed approach should be flown.
A circling approach, by it's nature can take you outside of normal stabilized approach perameters. Some airlines don't alllow them. Those that do, accept that where a procedure requires it, you can plan the approach considering and expecting certain deviations and then do it.
The whole philosophy of stabilized approaches is to give you a bench mark from which to measure your progress. If you do it the same way each time, you'll see any deviations quickly and correct back to profile.
Lots more can be said on this, but that's the basic idea.
Last edited by 5LY; 21st March 2010 at 09:41.