I play IVAO and I sometimes get curious about different positions that different controllers play on.

Let's take this airport, Birmingham UK, this is what the APP (Approach) screen looks like

Zoomed in EGBB_APP

Zoomed out EGBB_APP

What do the Faint Grey 'Hyphen-style (- - -)' lines around the airfield mean?

Secondly, if you look at the second image, what does the top right boxes mean (The same 'Hyphen-Style-line') mean, also?

If anyone could explain what all this means, that would be great!

Harry :)


2 Answers 2


They are the steps in the class D airspace around Birmingham and East Midlands airports. This is for Birmingham, taken from the VFR chart.

enter image description here

CTR is the control zone, which extends from the ground (SFC is an abbreviation for surface) to a specified altitude. CTA is the control area which rises in steps, away from the airport.

The two numbers are the base and top of the airspace (in feet) so 3500-4500 means the section of sky from 3,500 to 4,500 feet AMSL. FL is an abberviation for flight level.

The full approach plates can be found in the PDFs at the bottom of the NATS page for Birmingham.

(Apologies for the ropey annotation, it was the best I could do in a hurry)


The grey dotted lines denote controlled airspace. Outside of the two shapes is uncontrolled airspace.

The airspace to the North East is for East Midlands Airport.

If you were to find a VFR chart you'd see the same depicted.

  • $\begingroup$ Related $\endgroup$
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    Commented Dec 17, 2021 at 20:48

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