Wrong ILS course tuned for KSEA 16C and many others

[quizkid]

In X-Plane 12, Trying to fly ILS to KSEA rwy 16C from the north. Instead of tuning ISZI, it gives me ITUC, which is the 34C direction. When I hide the Navdata by renaming Custom Data, X-Plane 12 works as expected. I compared the X-Plane 12 default dat files to the Navdata current ones, and they do look like they should work.

It seems like a lot of X-Plane 12 ILS users should be reporting this same problem. It fails everywhere and with multiple aircraft for me, wherever there are reciprocal runways where each side has the same frequency. KSEA is a good test (KDFW works too) because there are 3 runways 16L/34R, 16C/34C, 16R/34L. The other runways fail from the 34 side.

I tried using the “Disable downwind ILSes” checkbox and it seems to disable the “upwind” ILS course as well!

It could be a bug in X-Plane 12.0, but they say to contact the 3rd party (Navigraph). This 100% reproducible problem does go away when I hide the Navigraph data.

[NAVData]

Hi,
thank you for your report … but we need a little bit more on information:

First, two points for clarification:

You wrote, it works with the stock/default data, that´s strange because the default data are also from us.
I have now compared the KSEA ILS information from the default data against the current AIRAC 2213:

AIRAC 2213:

 4  47.466605556 -122.317833333      359    11075    18 123840.337 IBEJ KSEA K1 34L ILS-cat-II
 6  47.443038889 -122.316661111      359    11075    18 300000.337 IBEJ KSEA K1 34L GS
12  47.437672222 -122.316650000      345    11075    25      0.000 IBEJ KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.437755556 -122.318083333      406    11075    18  59220.337 ICJL KSEA K1 16R ILS-cat-III
 6  47.460683333 -122.316833333      406    11075    18 300180.337 ICJL KSEA K1 16R GS
12  47.437672222 -122.316650000      345    11075    25      0.000 ICJL KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.465077778 -122.307738889      355    11030    18 123840.343 ISEA KSEA K1 34R ILS-cat-II
 6  47.434277778 -122.306394444      355    11030    18 275000.343 ISEA KSEA K1 34R GS
12  47.434333333 -122.306300000      369    11030    25      0.000 ISEA KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.428394444 -122.308063889      425    11030    18  59220.343 ISNQ KSEA K1 16L ILS-cat-III
 6  47.460816667 -122.309394444      425    11030    18 300180.343 ISNQ KSEA K1 16L GS
12  47.434333333 -122.306300000      369    11030    25      0.000 ISNQ KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.435194444 -122.311233333      418    11170    18  59220.341 ISZI KSEA K1 16C ILS-cat-III
 6  47.460747222 -122.312627778      418    11170    18 300180.341 ISZI KSEA K1 16C GS
12  47.435077778 -122.310975000      359    11170    25      0.000 ISZI KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.465097222 -122.310972222      367    11170    18 123840.341 ITUC KSEA K1 34C ILS-cat-II
 6  47.440444444 -122.312825000      367    11170    18 300000.341 ITUC KSEA K1 34C GS
12  47.435077778 -122.310975000      370    11170    25      0.000 ITUC KSEA K1 SEATTLE-TACOMA INTL DME-ILS

… and here from the default data (AIRAC 2112):

 4  47.466605556 -122.317833333      359    11075    18 123840.337 IBEJ KSEA K1 34L ILS-cat-II
 6  47.443038889 -122.316661111      359    11075    18 300000.337 IBEJ KSEA K1 34L GS
12  47.437672222 -122.316650000      345    11075    25      0.000 IBEJ KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.437755556 -122.318083333      406    11075    18  59220.337 ICJL KSEA K1 16R ILS-cat-III
 6  47.460683333 -122.316833333      406    11075    18 300180.337 ICJL KSEA K1 16R GS
12  47.437672222 -122.316650000      345    11075    25      0.000 ICJL KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.465077778 -122.307738889      355    11030    18 123840.343 ISEA KSEA K1 34R ILS-cat-II
 6  47.434277778 -122.306394444      355    11030    18 275000.343 ISEA KSEA K1 34R GS
12  47.434333333 -122.306300000      369    11030    25      0.000 ISEA KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.428394444 -122.308063889      425    11030    18  59220.343 ISNQ KSEA K1 16L ILS-cat-III
 6  47.460816667 -122.309394444      425    11030    18 300180.343 ISNQ KSEA K1 16L GS
12  47.434333333 -122.306300000      369    11030    25      0.000 ISNQ KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.435194444 -122.311233333      418    11170    18  59220.341 ISZI KSEA K1 16C ILS-cat-III
 6  47.460747222 -122.312627778      418    11170    18 300180.341 ISZI KSEA K1 16C GS
12  47.435077778 -122.310975000      359    11170    25      0.000 ISZI KSEA K1 SEATTLE-TACOMA INTL DME-ILS
 4  47.465097222 -122.310972222      367    11170    18 123840.341 ITUC KSEA K1 34C ILS-cat-II
 6  47.440444444 -122.312825000      367    11170    18 300000.341 ITUC KSEA K1 34C GS
12  47.435077778 -122.310975000      370    11170    25      0.000 ITUC KSEA K1 SEATTLE-TACOMA INTL DME-ILS

You see a 100% match - so, there is no difference between the AIRAC 2213 and the default data for the KSEA ILS information. So, the question is why does it works with the default data but not with the AIRAC 2213, when there is no difference in our data?

The second point is, that we are “only” the data provider, means we offer the datasets for the sims/addons but we have no influence of the logic how the data will be handled/used.

That´s only to clarify about our responsible function here and a big question mark, when the data are equal …

Ok, back to your topic:
You wrote:

@quizkid

It could be a bug in X-Plane 12.0, but they say to contact the 3rd party (Navigraph)

Please can you forward us the link about this posting, possible there are additional information what we don´t know.

The next thing is, you wrote:

@quizkid

It seems like a lot of X-Plane 12 ILS users should be reporting this same problem.

Thats not the case as you see here in our forum, nor had we received any ticket or an information from the dev´s from X-Plane. So, I assume it´s an isolated issue on your system …

Last but not least, to reproduce your issue, because I can´t:

• Please can you upload your flightplan
• You have set the correct ILS approach for 16C?

… I have done it and have the correct frequency for ILS16C (here from the default A330):

• Can you post a few screenshots of your legs-page after you have selected the correct ILS approach?

Thank you very much,
Richard

[quizkid]

Here’s an example FP: KPDX DCT COUGA DCT MARNR MARNR7 KSEA/GRIFY.I16C

I used the Zibo 737-800 here, but the same happens with the Cessna, and the ILS station is displayed in the Garmin 530.

Here 's the first shot where I’m lined up with the KSEA 16C ILS, showing ISZI in the FMS (which is correct), but the tuned ILS radio in the PD of ITUC (which is incorrect):

Then I let it fly like this, clicking “APP” so that the 737 would try to follow the ILS. The aircraft veered right, out of the ILS beam.

But surprise surprise, when the aircraft gets outside the beam enough, the ISZI station name shows up, but it’s too late:

Keep in mind that this behaves this way only when you are in the straight on beam.

I can reproduce this in the same way by putting a motionless Cessna in map mode. When you put the aircraft in the correct beam, (so on the 164 radial to 16C, and north of the airport, it tunes ITUC, which is the wrong value. If you slide it off center, it tunes ISZI. For 16C/34C, it behaves incorrectly like this for 16C, but for the other 2 runways 16R/34L and 16L/34R, the 34 sides tune incorrectly.

I guess I’m not saying that the Navigraph data is incorrect, rather my greatest suspicion is that X-Plane is treating Custom Data differently than default data, even though they are the same.

Unless you have other thoughts, I think I’ll try to get a fresh installation of X-Plane 12, then repeat the experiment, then do a single Navigraph update (and FAACIFP18 download) to see if the problem repeats. I was thinking that since your company is in the business of working between the sims and the data, that you would have known about this problem.

I’ve probably spent 10 hours on this. I’m not a rookie user, and I’m a Lead Software Developer at a large company, so I’d like to think it wasn’t a noobie issue.

Thanks, let me know if there is anything else you want to see.

[NAVData]

@quizkid

a single Navigraph update (and FAACIFP18 download)

One question?
Why do you use the FAA data too, when you use our data? Both are different datasets and I can only speak for our data.

Possible I understood you wrong here …

Cheers
Richard

[quizkid]

This comment is included in the file Readme.txt which is placed in /Custom Data:

*Also, you can place the FAACIFP18 file here, which you can get from the FAA website: Coded Instrument Flight Procedures (CIFP) *
If the file FAACIFP18 is found in this folder, X-Plane will load instrument flight procedures from this file.

I dutifully update FAACIFP18 from the FAA each time I obtain the Navigraph data using the FMS tool, according to the direction. I know that if it is the wrong version, X-Plane won’t even launch.

[quizkid]

Yes, I just removed the FAACIFP18 file from the Custom Data folder, and normal operation is restored.

I guess I wish that the readme.txt that is placed there was clearer. I thought that FAACIFP18 was the sole source of Instrument Flight Procedures, and the x.dat files were location and configuration data for the navaids and other objects.

Thanks for your patience. Hopefully this helps someone else. I’ve been downloading FAACIFP18 for years! I detected some malfunctioning ILS’es before but I thought it was a coding bug in X-Plane 11.

[NAVData]

You´re welcome - no probs … fine, that it´s solved.

You shouldn´t mix different datasets - our dataset includes a worldwide database, provided by Jeppesen which also offers the same data for the real-aviation. So, it´s not necessary to mix datasets and as you see, it results in strange, unknown bugs.

But anyway, to update our data is enough …

Have a nice weekend and happy flying - don´t hesitate to contact us again, if you have any question!
Cheers,
Richard