• Which the release of FS2020 we see an explosition of activity on the forun and of course we are very happy to see this. But having all questions about FS2020 in one forum becomes a bit messy. So therefore we would like to ask you all to use the following guidelines when posting your questions:

    • Tag FS2020 specific questions with the MSFS2020 tag.
    • Questions about making 3D assets can be posted in the 3D asset design forum. Either post them in the subforum of the modelling tool you use or in the general forum if they are general.
    • Questions about aircraft design can be posted in the Aircraft design forum
    • Questions about airport design can be posted in the FS2020 airport design forum. Once airport development tools have been updated for FS2020 you can post tool speciifc questions in the subforums of those tools as well of course.
    • Questions about terrain design can be posted in the FS2020 terrain design forum.
    • Questions about SimConnect can be posted in the SimConnect forum.

    Any other question that is not specific to an aspect of development or tool can be posted in the General chat forum.

    By following these guidelines we make sure that the forums remain easy to read for everybody and also that the right people can find your post to answer it.

P3D v3 RESOLVED - ADE not compiling new airport reference point

Hi Jon, thanks for the great ADE. (I'm running the latest release) I wonder if you could assist with a bit of understanding please?

I'm trying to change the airport reference point for the UK2000 Liverpool EGGP.
I want to do this because the airport reference point falls directly over the division between 2 sets of airspace over the airfield.

This is important to me because I'm trying to use it with VoxATC, which is getting confused and not recognising the class A airspace, and therefore treating EGGP like a towered field in non controlled airspace, instead of giving me a Liverpool Radar approach controller after hand off from the tower.

I am trying this because the dev of VoxATC, Tegwyn, suggested to me that this would probably be the cause of the problem I am experiencing, (which is known to him).

So, I opened up eggp_afx_UK2xTRM.bgl in ADE, and changed the position of the airport reference point. No problems so far, it moved where I wanted it. However, when I then compiled the file again and reloaded it into ADE, the airport reference point was exactly where it was originally - my edit had not been implemented? :s Is there any reason why do you know, or have I done (or not done!) something daft? :p

There's a fix for this problem. Move the ARP as you've already done, but then you need to create a pre-load bgl. Change the airport altitude to something else. Then change it back. ADE will create a stub file in Scenery/World/Scenery (xxx_ALT.bgl). You should be good.


Resource contributor
Or don't bother changing the altitude - just change a letter of the airport name, etc. using the tool in the Tools menu. Same result.
Hmm, I must be more dim than I thought. I tried changing a letter of the airport name Tom, as suggested. The _ALT file was created in scenery/world/scenery , but the ARP still doesn't appear to have changed when I reload the compiled bgl?


Staff member
FSDevConf team
Resource contributor
So exactly what are you trying to do - change the point of reference for the airport to match something else and you are finding that it is not changing? As I recall the ALT pre-load file does not affect that ARP. If you modified a third party BGL file and then recompiled it did you:
  • overwrite the existing one
  • compile to a new name
If the latter then are you sure your revised bgl is loading after the original? : https://scruffyduck.screenstepslive.com/s/help_docs/m/20268/l/199760-priority-matters I have not tried to change the ARP recently but I am aware that in some cases FS does not recognize the change. This came about when testing moving an airport. In certain circumstances the sim did not recognize the new coordinates but if they were changed a bit more then the airport does move. Obviously you do not want to move the airport. You might be able to confirm this behavior if you open your new compiled bgl and check if the reference point is what you set or not.
Hi Jon, I'm trying to change the ARP to a slightly different position because (as shown in the images attached), the airspace above EGGP is precisely divided over the current specified ARP.

Current rw chart
EGGP aerodrome chart.jpg

The ARP is directly over the boundary between Liverpool CTA-3 and Manchester CTA-4 as you can see.

eggp in ADE.jpg

VoxATC needs to know what airspace classification the airport is in in order to provide the correct controller types. In this case, Vox's dev (Tegwyn) believes the issue may be due to the ARP being directly situated on the junction of two defined sets of airspace and thus being confused as to what to provide.

"I think it's because the airport reference point is right on the airspace boundary if I recall correctly.

I believe that central line running vertically through the ARP is the same location as the airspace boundaries? So, in short, shifting the ARP ever so slightly east or west should theoretically place it within one airspace sector and so correct the behaviour of VoxATC within the sim.

I modified the 3rd party UK2000 bgl and recompiled it with a different name, then backed up the original and replaced it with the recompiled version.

I haven't tested it in sim because its not showing as moving even with ADE :)
When I reload my recompiled bgl in ADE the ARP is still in its original place :s

Thanks K

EDIT: I suppose I could also rework the airspace definitions to essentially merge Liv CTA-3 and Man CTA-4 since they have the same alt restrictions, but then it wouldn't be accurate :(
Last edited:


Staff member
FSDevConf team
Resource contributor
Can you please email me the original file you are working on so that I can do some tests: jon AT scruffyduck DOT co DOT uk
I moved the ARP close to the beginning of runway 09 and made a ALT pre-load file.

This picture shows were I placed the ARP and the new Lat/Lon is now N53 20.061 / W002 51.659


FSX Map Mode shows it moved N53 20.06 / W2 51.65 Altitude is my plane slewed up out of the way and not the airport.


FSX GPS shows it also moved to N53 20.06 / W002 51.65

that's the default file you altered, not the 3rd party UK2000 one :)

EDIT: or is that part of the problem in that I should have been editing that as well? :S
Hmm, now I repeated the whole exercise - and checked the _ALT file. All seems ok, this time ADE loaded in my recompiled file with the changed ARP. I don't know how that happened as I didn't do anything differently? The only thing I did differently is that I moved the ARP a greater distance than the first time - should that have made a difference at all? Thanks for your quick replies everyone, seems to be resolved now, maybe I did do something wrong before? :)
You should only alter the 3rd party UK2000 one.

I just wanted too be sure the ARP would move for the stock airport
Thanks all,
I used the amended recompiled file with VoxATC and now it does give me the correct RW controllers. All good :)
Cheers K