Hi Tom. I see the logic of having multiple AFCADs - it gives you flexibility. But I am not sure about having more than one active at the same time. You clearly have them arranged so that you won't get CTDs , but FS is only going to load one AFCAD at a time. So why leave more than one active in your setup, rather than have a few which you can change around?As I install new AFCADs, I always back previous versions up so that I can revert to one or another if necessary - but swapping them around can easily lead to traffic ending up in odd places, so I am sparing with this.Still, if your setup works and it's as you want it, great.M. :-)

The 'default' AFCAD is always active - it has to be because the addon AFCAD files don't have a lot of necessary data which is only in the default file.It's Addon AFCAD files saved with AFCAD2 which are the potential issue.The first part of every file created by AFCAD2 after the airport header identification data is a series of DeleteAirport statements.These tell FS to ignore any data from lower level files about: Apron LightsApronsFrequenciesHelipadsRunwaysStartsTaxiways (this includes all Nodes and parking spots in AFCAD)

What a fascinating thread this is. Thanks to everyone for their input so far.For the record I am one who has always filed addon AFCADS in the Addon Scenery Folder and have never had a CTD. (fingers tightly crossed)

"The 'default' AFCAD is always active - it has to be because the addon AFCAD files don't have a lot of necessary data which is only in the default file."Reggie, I am not sure this is always true. (I am assuming that by 'default AFCAD' (??) you mean the AP*******.bgl file in fs9/scenery/scenery? Correct me if not, but I can't see what else the term could refer to). There are quite a number of airport addons which I have installed (and many, many more which I have not) in which you not only have to install the scenery and AFCAD, but also remove the AP bgl file from the above folder. The problem then is that if anything is wrong with the new AFCAD installed, expect CTDs. This has happened to me more than once.M.

The default is in the AP9nnnn0.BGL file.These files often contains scenery objects, buildings, approach coding, taxiway signs, waypoints and navaids.They can also contain several other airports.Modifying the default AP9nnnn0.BGL file is always a bad idea. It can be done carefully, but there is no 100% decompiler for these files, so they can never be recompiled completely as the original.Personally I will not replace a default AP9nnnn0.BGL file unless I can see exactly the changes made in the replacement file. Often I can find better ways to use other files to achieve the same result.There are about three people I trust, and many more who I consider their modifications .... poor.

Perhaps this short video] will explain it better . . . [/b

I agree Reggie, you have to be careful and I too have my 'trusted' scenery designers when it comes to removing AP, HP etc. files.But to get things into perspective, as long as everything you remove is backed up, if you don't like what you see or problems ensue, then restoring things to how they were is just a few mouse clicks away.In addition, I regularly back up all 'sensitive' FS folders (e.g. 'aircraft', with all my modified cfg files; scenery; addon scenery; texture etc. etc.) to an external drive, via a batch file script which detects newer file dates, plus Acronis image files every month or two, so I feel fairly secure. (Tempting fate a bit saying that, aren't I?).M.

BTW, love the video!!!

From what I have seen, developers have only suggested deleting a default AP9 file to fix an elevation problem. Normally they provide a replacement that has been edited to be placed in the regional scenery folder.There are items in the default AP9 files which neither AFCAD nor the sdk BGLCOMP can create. For example, there are airports with multiple ILS equipments servicing a single runway (see KSTL for example). Only one ILS is "attached" to the runway (primary or secondary) via the available tools.This is besides many scenery objects in the AP9 files which AFCAD doesn't know about. For example, ILS elements, VORs, NDBs and markers all have scenery objects (antennas and shacks) placed with them.As far as placement, I have played with "AFCAD" files (with and without deleteAirport element) in sceneryBASE and sceneryworld and had bad results (but no CTDs).I have changed elevations with AFCAD files placed in the regional files, as long as the file name comes after AP9 (I use ZZ_).I have never had an issue with CTDs when AFCADs are placed in any other scenery folder. I do ensure deleteAirport is used when necessary. I can see problems with duplicate parking stands if taxiways aren't deleted in an AFCAD which includes them. Don't know if that causes CTD or just problems for the AI.scott s..

I've read this whole thread twice now and have tried to form an end conclusion for myself but apart from the necessary dodging of CTDs by having only one AF2_ file per airport with e.g. extra (AI) parking spaces, edited taxiways and the occasional extra ILS etc., this has now become rather difficult because of all your different technical views.The following has been my own method uptil now and I invite the technical experts to give their opinions. Right from the beginning of FS9 I have used FSNavigator and in order to get all my own AF2_ data correctly included in it's data base creation process, I removed any (edited or not) AF2_ files from addon airport scenery folders and placed them in a single dedicated scenery folder AND gave it the highest priority in the FS9 scenery library. For FSNavigator itself this method works fine and I took it for granted that this would also ensure correct use by FS9. However, the only thing which I have found uptil now that does not work 100% correctly is ATC which sets me up for a "visual" approach to a runway which, according to FSNavigator, should have a "home made" AF2_ ILS approach. This ILS can however be used normally but a small amount of ATC cheating remains e.g. by giving ATC the "Runway in sight" answer when required. But even this problem can be avoided by e.g. changing the wind direction at the destination airport so that ATC will direct you towards the official ILS end of the runway. As far as my almost four years of experience with FS9 goes, this seems to be the best method for having the least amount of problems.... and no CTDs .... yet.Hans

Appropriate little video there, that's how I feel too.I'm going to send that to a friend that I'm trying to train how to download a video file, unrar it and play it on his Windows Media player. It's been two days now of back and forth e-mail that's gone from the ridiculous to the sublime and back again to ridiculous.Ain't life grande. LOL