MMAA glideslope not aligned

Navigation Data ILS
1

Hello! I am a dev of a free airport MMAA, and I have been getting complaints about the ILS glideslope for rwy 28 not being correctly aligned. I was testing a lot!, believe me, and found that the configuration you have overrides the ILS I set for the airport, even with the default airport is not aligned.

So I removed your folder from the community folder and started to align it, and finally got it working properly, but when I set back your folders to community it still overrides my config.

Also with the new msfs config order, it still overrides the ILS I set.

Would you like me to share with you how I configured both ILS so both glideslopes are properly aligned?

Cheers!

2

Hi,
thanks for your report. I will check the position of the glideslope antenna at MMAA.

To compare and to reproduce it:

  • What coordinates have you for the glideslope antenna?
  • What elevation have the glideslope antenna?
  • Can I download your scenery feom somewhere to try it?

Thank you,
Richard

3

Hi again,
I have checked now the GS antenna position and I can´t see any offset:

RW10 (IAIA) 16.757975, -99.76028611

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RW28 (IACA) 16.75076944, -99.73714167

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I have also compared the GS coordinates from the stock MSFS
RW10 (IAIA) 16.75797488540411, -99.76028591394424
RW28 (IACA) 16.750769466161728, -99.73714157938957

The altitude is 12 feet - in our data also in the MSFS data. The same for the glideslope angle - exactly the same values. So, I can´t see any difference, sorry.

Cheers,
Richard

4

Hello!

Right now I am not at home, I dont have the values with me.

You can download the scenery from flightsim.to here or searching for MMAA.

5

The issue si not the antenna, that is placed fine! but the heading and magvar of the glideslope, the aligamient is a líttle bit to the left on both runways, and the touchdown is on the edge of the runways.

As soon as i get back home, i will share you the values. i dont have them right now.

6

Sorry but do you speak from the glideslope now or the localizer? Both are different …

The glideslope has no magvar, nor a heading …

Cheers
Richard

7

Ups! sorry my bad! but yes is the localizer! forgive me, please!

What I set for the correct alignment is this:

<Ils lat="16.76071351556363" lon="-99.76540739138169" alt="5.77269833348691" end="PRIMARY" range="50017.00000000000000" ident="IACA" magvar="-4.000000" heading="284.07" frequency="109.89999999999999" width="5.000000" name="ILS 28" backCourse="FALSE">
				<Dme lat="16.75175763226667" lon="-99.73664808646171" alt="3.69574209488928" range="30000.00000000000000"/>
				<GlideSlope lat="16.75175087669859" lon="-99.73662712495224" alt="3.69618456438184" pitch="3.000000" range="22000.00000000000000"/>
</Ils>
<Ils lat="16.74998321230603" lon="-99.73103228118445" alt="5.81223188992590" end="SECONDARY" range="22000.00000000000000" ident="IAIA" magvar="-4.000000" heading="104.07" frequency="111.89999999999999" name="ILS 10" backCourse="FALSE">
				<Dme lat="16.75902567243393" lon="-99.75995137768273" alt="3.76940454263240" range="30000.00000000000000"/>
				<GlideSlope lat="16.75903574276301" lon="-99.75998682782109" alt="3.77033493667841" pitch="3.100000" range="22000.00000000000000"/>
</Ils>

What I see on littlenavmap is that your MagVar is set for 5.8 East for rwy28, and 5.1 East for rwy10, and what I found is a difference of 4 East. for both runways.

Cheers!

8

Hi,
ok, I will check the localizer too.

Please can you post your runway coordinates too, that I can calculate the headings in your scenario. Thank you!

Cheers
Richard

9

Hi.

Sure!

<RunwayStart end="PRIMARY" lat="16.75102702380075" lon="-99.73431401391359" alt="3.56124803610146" heading="287.93859863281250"/>
<RunwayStart end="SECONDARY" lat="16.75977333283542" lon="-99.76235837791531" alt="3.67275370657444" heading="107.93859863281250"/>

That is fine?

Cheers!

10

Hi,
thanks for all the information … I have found out, that the coordinates in the AIP Mexico are wrong:

Here, directly from the AIP Mexico:

image
image832×319 26.9 KB

… and here you see the result - it´s offset:

image
image922×560 38.6 KB

This can only be changed by the Mexican´s - they are reporting these information to the data provider. So, our data are “correct” so far, but are wrong in the AIP. Sorry, in this case, we can´t do anything (also not, when we report this to Jeppesen because this should report to Mexico).

Sorry,
Richard

PS: we will try to fix the wrong AIP position manually in our parser - please give me a little bit of time, thx

11

Hello!

Well, that is bad! the problem is that in the airport they will not do anything about it, and there is no easy way to fix it. I will try to ask for some pilots and see.

But I can assure you that the thing you are pointing to in the image is a bridge they use to access the localizer antenna when it is flooded.

image
image1243×807 41.7 KB

As you can see, is perfectly aligned with the center of the runway, the same for the rwy10 localizer.

I will fix the positions on my scenery, and try to align it better with the magvar instead of increasing or decreasing the heading of the localizer.

I hope it can get fixed!

Cheers!

12

Hi,
no, please don´t touch your scenery … it´s ok! I have found a way to correct this … I will write you again, when you can try it … thank you!

By the way, thanks for the picture but it shows only that the aircraft is aligned what is good for landing but it doesn´t show if the ILS signal is aligned too. The antenna (and you see this very clear on the google maps) must be in the center line - it´s possible that the power station is outside and I guess this is here the case to avoid the flooding. But again, I´m pretty sure, that the coordinates are not correct in the AIP.

Again, please don´t change anything - I come back to you, when I have uploaded the new data.

Thank you,
Richard

13

Hi again,
please can you re-install (remove it and re-install it) the current AIRAC cycle and can you try the ILS approach again. Let me know, if it´s better now … it should :slight_smile:

Cheers,
Richard

14

For sure, as soon as I get home I will test it and let you know!

Thank you!

15

I just checked and nothing changed, it is the same thing, a little bit off to the left of the center of the runways on both sides.

16

Hi again,
I strange but I know possible why now … your ILS course is 104.07° but it should be 103° which is 1.07 degrees off and thats exactly the offset to our data. Your approach course is wrong, I guess you have aligned to the center line in the sim.

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Also, the magnetic variation is 5° East and not 4° as in your configuration.

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image783×777 158 KB

I´m pretty sure, that this offsets are the difference between your scenery data and the real-world data.

Cheers,
Richard

PS: the localizer is in the data now exactly on the same position as in your scenery but again due the 1 degree offset, the plane can´t be aligned to the centerline.

17

I already did that yesterday after testing it for the first time, I changed the values to 103 and 283 and mag var 5 east, and still, the alignment is to the left. The custom ILS I set is aligned, just at the center, using the current in-game heading of the runway.

I will ask current Mexican pilots on a forum to see if they know if there is an offset on the localizer to see what is going on.

I think maybe from what I have seen that the satellite image is not aligned with the current heading because the scenery I made is just on top and same orientation as the satellite image. And even with the default scenery, your alignment is not at the center.

Can I ask, what is the runway true heading you have, please?? mine is around 287.9 degrees.

Cheers!

18

Hi again,
here the requested true heading - in the brackets are the runway-threshold-center coordinates:

image
image1920×755 187 KB

RW06 (16.75366389, -99.76221667) - RW24 (16.75966667, -99.74753056):
66.8835387° (24-06 = 246.8835387°)

RW10 (16.75999722, -99.76308611) - RW28 (16.75077778, -99.73364167):
108.10341472° (28-10 = 288.1034147°)

Hope that helps,
Richard

19

Hello!

I just changed the runway true heading to 288.1034147, magvar 5 E, and fixed all aprons around the runway, and your approach and touchdown is still at the edge of the runway.

Cheers!

20

Hi,
I have tested the AIRAC 2211 rev. 2, where I have corrected the ILS antenna with the default stock scenery and here, I´m fully aligned … So, it looks correct now … sorry.

Here, 15 ft above … absolutely aligned to the center line now:

image
image1920×932 149 KB

Cheers,
Richard