Originally Posted by
Lemon Jello
Well, consider the scenario where you are at the head of the pack of a bunch of arrivals. They ask you to maintain .79 or better in cruise, transition to 310 or better in the descent, and comply with all speeds on the STAR. Adjusting the CI will let you do a managed/managed descent meeting all speed/altitude constraints. Whats the big deal? Just easier to do it that way.
Select .79 and put .79 and 310 in the descent perf page. Start your descent and manage your speed at the calculated top if descent. Then you're not guessing on the CI.