When to start your decent

Hi there! I’m new to the IFC so if I say something wrong, please correct me.

As of today, I’ve been on IF for around three months. And I’ve slowly learnt the basics.

Here is a quick guide on how to perfectly time your decent for beginners!

(Note: I recommend doing this before takeoff)

All you have to do, is multiply your cruising altitude by three. The answer is NM away from you destination you should start your decent. Remember to take the last three digits off!


Cruise altitude: 30,000

30,000 x 3 = 90,000

I take the last 3 digits off

I should start my decent at 90nm.

Also set your VS from 1500 to 2500.


Welcome to the Forum! Thanks for the information. I will use it when flying 😊

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I’d recommend a VS between -1800~-220

And add an extra 10 nautical miles to that due to winds.

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I thought adding that at the end but I needed to eat my breakfast lol!

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I tend to just use the first three digits and multiple that by 3 and add 10-15 depending on how heavy you are and decend at a constant rate but they both work perfect

I usually use the remaining flight time to to calculate when I‘ll have to start the descent. Assuming -1800 feet per minute (FPM) you‘d need to start your decent from FL340 to 16,000ft when you are about 10mins away from where you want to have reached 16,000ft. This method only works well with a constant speed which makes it unreliable on longer descents and lower altitudes though…

Welcome to the community! That’s a smart method of descending ;)

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Usally I would ensure the a/c is under 18000 ft. when there are 50 nm to the destination :)

I usually use the following formula to determine when to begin my descent:

At time [in minutes] = (Cruise Altitude)-10

I usually start at around -1000 to -1200 ft./min and gradually increase or decrease the VS depending on the flight parameters. I rarely ever exceed -1500 ft/min though.

My typical final cruising altitude is anywhere between FL380 and FL430, so using the above formula, I usually begin my descent around the 28-33 minutes to destination (ETE to Dest) mark. This is typically how a long a realistic descent lasts in real life commercial services. Including the slowing down and pattern, my total time from initial descent to touchdown lasts around 45 minutes.

Although this is sometimes a crude way of doing it, I find that it gets the job done while allowing for flexibility in my approach. However, if you want to go very mathematical about it, I recommend some of the links given above. Hopes this helps!


I tend to find that an early descent is unnecessary, I start my descent from cruise about 15 minutes before autopilot tells me I’m going to get there

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