Okay for example, FL410, GS 420.
ATC asks you to be at FL 250 at a certain waypoint.
Take into consideration ROD = 1000 FPM
You're going at about 7 mile/minute
That makes it 13 minutes to lose the 13,000 feet, and 7 miles per minute
13 x 7 = 91 NM
You start your descent 91 NM beforehand.
When numbers get a little bit confusing, is there an easier way to do this?
Does the MCDU usually do this for you, or are you required to manually do this?
Cheers