AFCad Issue

[Guest sgray2]

I am new to creating scenery, therefore, excuse my relatively simple questions. I created an AFCAD for the purposes of placing an ILS and VOR/DME. Everything seems to work just fine, but I noticed in FSNav that an ILS localizer is shown on both ends of the runway and indicated as 110.30 ICAO 18 and 110.30 ICAO 36. I only install an ILS on runway 18 and did not include a back course option. I would appreciate any advice or comments as to how to only show the one ILS in FSNAV.

[scott967 62]

In the US anyway, many runways are set up with ILS systems which use the same localizer frequency on each end. This is not a "backcourse". In the US, the airport is required to have a lockout device, which is controlled from the tower cab and only allows one of the two ILS' to transmit. They are only allowed to have both active for 30 secs for maintenance purposes. (This isn't implemented in the sim though). Supposedly the FAA rules are drawn from ICAO convention Annex 10, but I haven't found a downloadable (free) copy of that yet. Also in the US, many of the newer localizers use log-periodic dipole antenna arrays, and these do not provide much radiation in the backcourse direction (25 db down from the main beam). In your case, I assume this was a default airport that you modified, and it had an ILS setup on one end (either primary or secondary) and you added one on the other end. If you turn on navaids view in AFCAD, you should see localizer and gs feathers on both ends, and if you look at the runway properties it should also show the ILS active on both ends. If the default AP9 has an ILS that shouldn't be there, you can't get rid of it, only move it out in the country and reduce its range (also change the freq to an unused one so it doesn't interfere with any other ILS in the area).Another IRL thing is that many localizers actually transmit 2 frequencies (very close to each other). The airplane tunes into the main beam but also receives the second one. The second beam provides a wider signal, but only forces the aircraft's course needle full left or full right. When the aircraft gets within the main beam, that beam over-powers the second one, and provides the proportional deflection of the needle. The idea is that the pilot can see that he is left/right of desired course, without seeing the "off" flag instead.scott s..

[Guest sgray2]

Thank you for your reply. Let me provide some additional information and see if that helps. I did not start with an existing default airport, I created a new one. I added a runway and then added an ILS to Runway 18. Within AFCad, the ILS and GS appear but only on Runway 18. In FSNav, however, an ILS appears on both ends of the runway.

[RFields5421 1]

In AFCAD - do you see two localizer horns when you have the Navaids showing?When you created the ILS - did you create it for the base end or the reciprocal end of the runway?Does your runway display as 36/18 or 18/36 when you look at the designator in the Runway List?In the Runway properties - is the ILS designator shown under the correct runway? Is it shown for both runways?Are compiling and decompiling the AFCAD file, or do you have backups of each major stage?When you have FS open, does the Map View show two localizer horns?Have you rebuilt your FSNav database since your last update of the airport AFCAD?

[Guest sgray2]

>In AFCAD - do you see two localizer horns when you have the>Navaids showing?No only the one on Runway 18>>When you created the ILS - did you create it for the base end>or the reciprocal end of the runway?It was created on the base end or Runway 18>>Does your runway display as 36/18 or 18/36 when you look at>the designator in the Runway List?It displays as 18/36>>In the Runway properties - is the ILS designator shown under>the correct runway? Is it shown for both runways?It is only shown on Runway 18>>Are compiling and decompiling the AFCAD file, or do you have>backups of each major stage?If an using AFCAD to create and save my file. I don't see an option to compile or decompile. I just saved the project when I was done and it created the .bgl file>>When you have FS open, does the Map View show two localizer>horns?FS Map shows one ILS horns on Runway 18>>Have you rebuilt your FSNav database since your last update of>the airport AFCAD?I rebuilt my FSNavDB after each change, following starting FS then closing it.Thank again for your assistance.

[RFields5421 1]

Thanks for the replies.It appers to be an FSNav only issue - might want to check their support forums.FYI - when you open AFCAD, it decompiles the .BGL file and when you save it recompiles.This induces rounding errors at many places over the airport. The easiest to see is a long taxiway with many turnoffs. It will be straight initially, but over many edits, will develop a zig-zag taxi path.Also AFCAD can have indexing issues sometimes when nodes and links are removed.When I'm working on major project, I'll save versions of the AFCAD before each major change. That way if the change does not work well, I go back to the version before the change, not opening the 'bad' AFCAD and removing the change.

[Guest sgray2]

Thanks Reggie, I will go to the FSNav Forum and see what I come up with.