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We didn't have FMS in my day.
As a rule of thumb, from light, jets throught to heavies, we used this. 3 x the altitude. 3 degree decent angle. So, if you were at 30,000ft x 3 = 90 miles plus 10, for TOD. If you were going down at less than less than 3 degs, and unable too reduce power (pressurization), increase speed, more drag.
Higher the A/C weight, the more distance required, for a given speed. (Same reason a glider carries water ballast). Keep a check, if you are on profile, during descent.
We didn't use calculators, as they weren't around then either. K.I.S.
As for the use of spoilers in the air. Dont use them, in normal procedures. Observe an a/c landing. As soon as spoilers are deployed, watch the horizontal stabliser. The movement, caused by disturbed airflow from deployed spoilers, is disturbing to watch. Imagine the movement at twice the A/S. With prolonged use in the air
If you bend a piece of metal often and long enough, it will fail.
Last edited by RichardJones; 22nd February 2025 at 10:55.