Flight Levels

This is a quick and easy tutorial: flight levels. I haven’t seen a tutorial on this, made most of you know, but maybe some of you don’t.

Note: Flight levels start up use at 18,000ft.

A flight level is expressed as a 3 digit number referring to “thousands” in feet. It always ends on a 0 or a 5, and when someone says “Descend/Climb and maintain FL110”, they mean “Descend/Climb and maintain 11,000ft.”.

In ATC communications, “FLXXX” will mean "Flight Level (Number) (Number) (Number). Here’s an example, FL240 will be pronounced as “Flight Level (Two) (Four) (Zero).”

If the flight level has two digits (Example: FL020), FL020 will be the same as 2,000ft.
Example: “Descend/Climb and maintain FL050” is the same as “Descend/Climb and maintain 5,000ft.”

That’s about all, I hope you guys learned something new and I wish you all a great day!


Thank you @ItsPerses

Flight Levels start up use at 18,000ft (FL180) in IF.

You’re more than welcome :)

I forgot to add that, time to edit!

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Not always IRL

In Europe it is usually between 3000-7000 depending on country, Malaysia is 11000 for example as well.

Thank you for the bit of information, do you think it would be better if I edit it for the different countries? I live in the US, so I didn’t know that.

@ItsPerses I can prepare you a list and send it to you via PM for you to add if you want :). Glad to be help.

Of course!

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A bit more background of the origin of FLs, why one transitions from using the altimeter to FLs at a certain altitude, and why FLNN0 is not necessarily the same as NN,000 feet AGL, or even MSL, would be helpful.

Like this kind of background?

Yes. Some of that may not apply in IF, but at least an explanation of why “Flight Levels start up use at 18,000ft” and/or why it would be different IRL in different regions is interesting/helpful IMHO…