How to descend in a realistic way

I want to know how real pilots calculate descent and how I can do this in IF.


I hope this video helps you.

I watched that video a thousand times and I don’t understand at all.

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This should help you as well.

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That’s not realistic. I can assure you that.

Use this formula:

FL of Cruise - Desired FL / 3

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Oh, boy…

If you want the answers that will begin pouring in, they’ll be the same ones that can be found in any of the threads found in this search:

The answers will often be contradictory, generalized rules-of-thumb which offer only broad approximations, or just random musings of little import.

If you want a general answer, any of those threads will have hundreds of them, and I don’t think we need to revisit them here, yet again.

If you actually want to account for groundspeed and do actual math,

[(Altitude to lose * Groundspeed) / (V/S * 60)]

Will tell you how far from your intended point to reach a certain level to begin your descent. Here you chose the V/S you’d want to use,

[(Altitude to lose * Groundspeed) / DME to chosen point / 60]

Will give you the needed V/S to reach your chosen altitude by your desired waypoint at your current Groundspeed.

Anything which doesn’t account for Groundspeed is a rough approximation.


Utilize your arrival airport STAR (Standard Arrival Procedures) that applies to your route.

You still need to calculate TOD to determine when you need to descend in order to make it to the assigned altitude for the STAR.

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I have searched obviously but I discovered that almost all of these methods are not realistic.

Agreed, but you’ll receive the same answers here.

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Use a descent Calculator!

So what am I supposed to do to find out how to descend realistically.

Your not going to get absolute 100% realism. What everyone is suggesting is as close as you are going to get.

Google it.

I did everything I could before coming here. I googled, watched videos, visited the threads on the IFC, but I still don’t understand how i’m supposed to calculate the VS.

Realistically, Aircraft have LNAV. Unfortunately, we don’t have that in IF just yet (although, I believe maybe IF Asssistant does, I’m not positive).

Realistically, Aircraft and EFBs all have some form of descent calculation or glide path, etc.

I’m not a pilot, so I don’t want to make any bold, inaccurate statements as to how pilots do it, but I seriously doubt commercial pilots are up there winging it with rules-of-thumb.

Personally, I use those equations I have above. Whether that’s “realistic” or not, I have no idea, but for what is available in IF, it works 100 percent of the time.


Descent VS = Mach Speed x 1000 x 3

I just have an app where I put in all of the facts about my flight and it tells me when to start decent etc.