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I was flying a series of practice approaches at KSNA this afternoon. The last approach was the LDA RWY 19R approach. I was able to tune in the localizer and receive the proper identifier but the CDI would not provide any course deviation indication. I alerted the controller and was cleared for a visual approach.

I am curious if any other x-plane users have experienced the same issue on this approach.


I did some digging and I think I have found the problem. The earth_nav.dat file includes an entry for a glideslope for this localizer (which should not exist). The frequency specified for the glideslope (108.3) is the same as the frequency for the localizer and this was causing a conflict so the CDI would not function. By removing the following entry from the earth_nav.dat file, the CDI responded correctly:
 
6 33.67987800 -117.86729400     43 10830  10  300208.442 IOJW KSNA 19R GS

In addition, I was not receiving any DME information from the localizer. I found that the earth_nav.dat file did not contain an entry to activate DME on this localizer so I added the following entry:

12  33.67987800 -117.86729400     43 10830  18       0.000 IOJW KSNA 19R DME_ILS
 
After making these two changes, everything appears to be working correctly. I have forwarded this information to Robin Peel so hopefully it will be corrected in a future x-plane data update. I am not really too familiar with editing this file so I'd be happy if someone more knowledgable could confirm the changes I made. So far, it seems to have fixed the issue for me.


Ken

Completely unrelated to this, but could you post here if/when he responds to you? I've been sending him various stuff over the past few months, but he seems to have disappeared off the face of the planet.

I just got word back from Robin that this fix is being incorporated in the updates to X-plane's earth_nav.dat file. A coding error back in 2005 had caused the incorrect entries.

Ken,

I forgot all about this post and attempted to fly this LDA RWY 19R into SNA last night. I was able to identify the localizer, but was never able to join it. ATC pointed out that I was east of the localizer just as I was about to question it (I had the field in sight and noticed the localizer was never going to come in).

Thanks a lot for posting this! I will get my file updated and will try the approach again.

If you are editing the file, don't forget this one as well.

viewtopic.php?f=5&t=2339

It takes care of the missing DME issue you had at KCRQ. Robin didn't mention this one (I think I had sent it to him). I've also given him a list of airports in ZLA which need to have their identifiers updated (all non-towered).

How do I download Robin Peels new Nav Data, I see from his site (http://data.x-plane.com) that the downloads don't seem to have been updated from the middle of last year?

Thanks

Yeah that's the 'newest' data. The last I heard from Robin/Austin/Ben, was in the waning days of 2012, and essentially was told that Robin is simply traveling too much.

Just got a note from Robin indicating that he has updated about 25 ZLA area airports to reflect their current FAA designations. It will be included in the next X-Plane database release however he didn't indicate when that release would be posted.

FYI - Robin Peel has released an update for the X-Plane data files (http://data.x-plane.com/get_data.html). The update includes the correction for the KSNA - LDA RWY 19R approach. Also included are updates to the ICAO identifiers for many of the private airports within ZLA.

Thanks for keeping us updated.