Transition Altitude

Hey IFC!
I was just wondering something about transitions altitudes. Ik the format to calculate it, it’s Airport Elevation + 2500 = ___ rounded up to the nearest 500.

Now, to get to the question, let’s say an airport is 20 ft MSL. If I use the format above the transition altitude should 3000, cause 20 + 2500 = 2520 (rounded up to the nearest 500) = 3000. However, is it worth rounding up 480 feet? Can’t the altitude be 2500?

When it’s that close, you could go either way. I personally always round up, but that’s just me.

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Just always round up. No matter what. Even if it’s close. Better safe than sorry

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You can do 2500. Perfectly acceptable. 50ft or less you don’t have to go up.

Always better to round up to keep more separation between pattern aircraft and aircraft flying the transition, find out more in the wonderful user guide!

Cign :)


Oh ok, What I get out of all your answers is that I can go with 2500 but it’s safer and better to go with 3000.


That’s correct!

Either one works. It’s really up to you.

Ok thanks for your help guys! Does this also apply to pattern altitudes?

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Yeah, pretty much. If the elevation is say, 5ft, you don’t need to be flying at 2000ft for jets and 1500 for props.

Patterns are just 1000AAL for GA and 1500AAL for Jets rounded up to keep the needed separation. Once again all included in this :)

Yes, I know. I was actually wondering what to do when let’s say the elevation is 10 feet.

Thanks for your help @ToasterStroodie

I’d stick with the 50ft or less don’t round up rule. Just make sure VFR separation is maintained.


Will do! Thanks a lot!


@ToasterStroodie explained it well. Just hypothetically you could even allow a transition at 2500 when the elevation is 499ft MSL. It copes with the minimum VFR separation rules of 500ft as you know that aircraft flying locally (pattern work) always acts as VFR flying.

I had some similar concerns some months ago when doing my IFATC Recruiting process that ended up with a talk with the recruiter, and agreeing that although you can always round to the nearest 500 you better not round to the lower mark when the number to round exceeds by more than 100 ft the lower mark.

If you have any more questions or concerns feel free to PM any ATC Supervisor



Thanks a lot!

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Here’s a tutorial that may be of use. It’s made for ATCs but also useful for pilots,

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