What do these altitudes mean?

I don’t understand, and also different airports have different altitudes. I know the number of rings represent the class but I’m not sure what these altitudes for each ring mean.

You know, that’s a good question I have wondered that too… I will definitely be checking back to see what the answer is!


That would be the ceiling of that airports airspace, meaning above those altitudes you can transition through without issue

‘Without issue’ meaning you don’t have to request it through ATC, correct?

1 Like

Oh never thought of that

You’d contact ATC if you are below 10,000 ft. Above it, there’s no need to request transition. Here’s more info on that

1 Like

Why would they put 8000ft → 4000ft if I only need to know what the ceiling altitude is? If I’m between 4000ft to 8000ft I have to request transition? What about at 2500ft → 4000ft? and SFC → 2500ft?

I thought it was the range of altitude you had to be between to capture the glide slope for the ILS approach.

I think this shows at what altitude the airspace for the airport is. For example, the airspace in the ring closest to EGLL is from the surface area (ground) to 2500 ft agl. I’m not 100% sure but that’s my understanding of it.

1 Like

Not quite, glide scope is not based off altitude but rather distance from the airport in nautical miles, I think.

This may help

Then what if I’m above 8000ft and outside the outermost ring? Does that mean I’m not in any airspace?

That’s outdated, there’s no way to know which airspace ring we’re at unless we focus on the HUD map which is impossible for me if I’m going to focus on the localiser and glidescope to make a good landing.

A controllers airspace for tower is ground to 5000 ft agl and 5 miles around the airport. It looks like the altitudes on the rings are speed restrictions if you want to be realistic according to a thread someone posted.

This is mostly just an aid for realism. Here is an example of how this would be displayed on a chart. This is an excerpt from the “Los Angeles FLY” chart, which can be found on Skyvector.

I have circled one of many (and I mean many) airspace blocks shown on this chart. The airspace of an airport is not always a perfect circle. For KLAX, it’s an odd shape that extends to the east for approaching aircraft. For that particular circled segment, it has a ceiling of 10,000, and a floor of 2,000.

Combining all of the different ceiling and floor segments, we can create a very strange looking picture that most people don’t realize.

Here is the actual airspace for KLAX.


The KLAX airspace happens to corrolate with the western flow glide slopes, however it is in no way a way to determine at what altitudes to intercept a glide slope at. You can use approach charts and cross reference fixes in Infinite Flight to determine that.

I hope this helped. If you have any questions let me know!


Those would be the upside-down wedding cakes of a Bravo airspace.

More on that here: Airspace - Wikipedia

This is something I’ve always wonder about too. I’m glad the question was asked. It’ll definitely change the way I fly now.

First, as far as IFATC is concerned, controlled airspace is simplified to surface to 5,000 AAL and a radius of 5nm. So if you’re just passing through and are further than 5nm or higher than 5,000 AAL then communication with the Tower at that field is not required. If you will pass through within a 5nm radius AND lower than 5,000 AAL of the airport, then you must contact the tower and request transition. If denied, you must remain outside the 5nm surface to 5,000 AAL airspace of that airport.

Now to answer the original question. Airports in IF have a simple airspace shape, compared to pretty much every Bravo airspace in the real world. It’s just an upside down wedding cake. Deltas will have one tier, Charlies will have two tiers and Bravos will have three tiers.


This is what airspace for all airports in IF would look like from the side and the rings at the bottom of the image is what you see in the IF map. So in your example of EGLL, looking at Class B airspace, the bottom cylinder holding everything up is from the surface to 2,500ft. The middle cylinder is from 2,500ft to 4,000ft. The cylinder on top is from 4,000ft to 8,000ft. That’s what the rings are showing you. If you’re anywhere inside those cylinders, you’re inside Bravo airspace. The regulations associated with flying inside the various airspace classes are readily available online, such as the resources linked above. Bear in mind, as shown just a few posts above, airspace in the real world is rarely perfect circles, even for some Class D airspace.

In the real world, you’re always in some kind of airspace. In your question posed above, you could be in Class A (18,000 to FL600, IFR only, VFR prohibited), Class E or in some rare cases, Class G. Everything above Class A is Class E as well. For IF purposes there’s just two kinds of airspace, within the 5 out/5 up cylinder around airports and everywhere outside of that.

I should clarify that aviation authorities in different countries determine how exactly the ICAO airspace classifications are used. Netherlands for example has Class A all the way down to 1,500ft in some areas, where as in the US, it’s what I wrote above.


As mentioned by @JeromeJ these are indeed the airspace ceilings.

For requesting a transition, IF assumes the airport ceiling to be at 5000 feet AGL.
See more here:

I suppose it is something similar about it.