I have been working with ADE v21 HF5 and the SDK to add ILS to the KTNT airport for more than a week. I successfully added the ILS, GS, and and NDB to the KTNT airport and scenery. However, the navaids are totally non-functional when tested in the sim at the airport.
Based on all the research and reading I have some observations and questions.
- Even if you add an ILS to an airport, it will not be functional in any aircraft that uses Navigraph navdata? This eliminates the PMDG aircraft from using a created airport.
- I read that MSFS would read the navdata from the airport scenery if using an MSFS base aircraft. I tested this using an MSFS aircraft but no signals.
- Even if you could add ILS info to the Navigraph data it would get wiped out after an AIRAC update.
- Will the same thing happen with an MSFS update? My tech brain tells me yes.
- Based on my experience so far it seems fruitless to create a fictious airport for instrument practice as it will not work with Navigraph data aircraft. (KTNT used to be an airline training field decades ago).
- Should an MSFS aircraft see and use navaids in a Community airport scenery? I load Navigraph data into MSFS with each update.
It has been a learning experience but also frustrating due to the SDK and MSFS constraints. I believe MSFS 2020/2024 needs the ability to read custom navaid data and/or store it in MSFS in addition to Navigraph data. Any thoughts are welcome.
My approach to local navaids was to rely on the global definitions by Navigraph. The only exception was my own home airport KCRP where Asobo had selected LOC instead of ILS (among many other deficiencies I reported to Zendesk over a year ago). I’ve stopped using the ADE because it never got out of alpha development and the developer has given up due to the wrong information contained in the SDK.
Since KTNT has no ILS in real life (at least according to Skyvector) and no NDB that I can see, I assume that you came up with some ICAO IDs for both. According to the docs, you can create your own as long as they don´t interefere (I assume they mean overwrite/change) existing navaids, approaches, departures (See Note On Navigation Data here in the docs). Your custom defined navaids would never be loaded.
Maybe you inadvertently have repeated ones?
Ref 1), that is my understanding too, since they use their own nav data even if you don´t own a Navigraph subscription. The Fenix is in the same boat (maybe other airplanes too), since they do not use the default MSFS navdata either (unfortunately, in my opinion, since the default gets updated in every AIRAC cycle anyways). I remember reading somewhere that they do so because it was too hard to use the default. Maybe so in the beginning but both FlybyWire and Working Title have shown how it´s done.
Ref 2), I think it´s not the fact that they are base aircraft but that they use default nav data. I run some tests many months ago and I could make an (imaginary) ILS work (I don´t use Navigraph)
Ref 4) Assuming that you added the navaids to your custom version of KTNT, the navaids “live” there, not in the sim´s nav database, so MSFS updates should not affect them.
My opinion is not so much that MSFS limitations are to blame but airplane developer´s decisions. As to Navigraph, I see it the other way around: they are modifying the sim, so it´s up to them to find solutions for user defined data.
With WT developing in-game charts for MSFS 2024 most of this trouble should go away (if airplane developers finally embrace built-in nav data!)
Sorry for the long ramblings, this topic is close to my heart 
Thanks for the responses. KTNT had an ILS and NDB in the way past…I have the charts. That said, I can see the Navaids in the XML but as you highlighted, I have not found an MSFS aircraft that will detect them. Since they did not exist in the MSFS KTNT I assumed I did not have to use the delete functions for ils. If you zoom way in on the world map you can see the artifacts from the old ILS. You can do a free flight to the stock KTNT. I learned to fly the PMDG 737 in the FSX days using Timothy Metzinger’s fantastic tutorials. The base airport was KTNT with an ILS on 108.3 (IKTNT) and an NDB for IAF on 227 (TN). Have been trying to re-create the original scenery and airport to repeat the tutorials.
I have the CPFlight 737 hardware (overhead, mcp, efis, cdu, and com/nav units, Thrustmaster TP pedal system, and the Next Level flight chair system as a home cockpit. Was flying military aircraft for a couple of years and wanted to get back into the heavies.