Question

[Chris_S]

A search would have shown this.

How to compute the TOD (Top of Descent) - Thumb rule

Hi There, there is an easy thumb rule for descents, that is important to know for pilots and ATC Controllers as well: subtract the current altitude from the target altitude, eg 30000ft - 10000ft = 20000 divide the result by 1000 and multiply with 3 and you will get the miles 20000 : 10000 = 20 x 3 = 60 miles so you have to start the descent 60 miles away from the point where you plan to be at 10000 IMPORTANT: descent rate is no less than 2000ft/min speed is not higher than 280kts til 10…

I don’t think a calculation question should go in support.