In an A320 or 777-300ER When would you know when to start desending, it’s been a question that I have wanted answers for a while now. If anyone could help, it would be much appreciated.

I am falling around a hundred nautical miles.

Check out some of these topics :). Or if you want to take the easy way out, you can always use this tool ;)

Take the first 2 numbers in your height, add 100. Subtract height of airport. Has never failed me, and is quite simple. Descend at -2000vs

Ex:

Airport is 3,000 ft in height and your cruise is at 30,000. 30,000-3,000=27,000 and take the first 2 numbers and add 100 which gets you 127. Hope this helps! Ask me if you have questions about this

At around 190nm I start my descent with a VS of 1400 usually. I’m not looking to be realistic but it’s the general set up I have most of the time. 3 x your current alt will roughly give the distance at which you need. So 330 is your alt = 33*3= 99nm but this will require a VS of around 2000 so keep it safe and start 150nm away for example with a less steep descent.

Thank you for the help

So you start to descend 127 nm away from the airport?

How do I find out the runway elevation?

If you click the airport dot then it should tell you the elevation.

ah yes

Thank you

No no, depends on your altitude and airport altitude. That was just an example I gave 😊

So where did you get the 127 from? Did you just add 1 to the 27? Sorry for the questions, just a bit confused.

I added 100. And it is totally fine! Keep asking away I am glad to help a fellow pilot!

This what I usually do I got it from a topic somewhere on here I forgot where it was or what I searched but you take your current altitude say your cruising at 34,000 and you wanna descend to 3,000 subtract 34,000-3,000 you get 31,000 divide that by 1,000 or 1 and you get 34 times that by 3 31+31+31 you get 93 So you should start descending That far from your destination or what I do I usually add 10 miles so I descend like 110 or 120 if I feel like I’m too fast I usually slow down for descend around like 130 miles then begin my descend at like 115 or 120 with a vs of 1800 make sure to descend at vs of 1500-2500 but yea that’s usuallly what I do hope it helps

No need to calculate that much, just use http://aerotexas.com/desplan/desplan.php

Its pretty accurate and I never had any issues with it.

Some tips:

FL300-350: 130nm, -1800fpm

FL350-380: 140nm, -1800fpm

FL380+: 150-155nm, -1800fpm

This is also quite accurate, however you need to monitor your distance/height and change the V/S if needed. (Oh and don’t forget to distract the airport elevation from your initial climb)

How to get the answer

Several good threads already on this if you search ( already linked above)

Rule of thumb take your Flight level (ie 35,000 ft =FL350) then devide by 3. Then add about 20nm for slowing down, especially in the B777!

Ie FL350 = 350/3 = 116nm + 20nm = 136nm DTG.

REMEMBER to make alterations for height of airport above sea level.

PS this is similar to what professional pilots do IRL

o as an example would this be right

my altitude is 35000 and the airport is 2,000 ft height. It would be 3500-2000 which is 33,000 and add 100 to the first two numbers which would be 133. So I would be descending 133 nm away from the airport?

Thank you for all the help

Thank you :)