As per title: I found that many sceneries in MSFS (also some payware) have ILS issues.

For example, the localizer is offset where it should not be, or more importantly in almost 90% of sceneries, glideslope and PAPI are way off. If you follow GS until touchdown you'll end up very very high and miss the touchdown zone. 

This happens also in airports where there are CATIII approaches, so where you should be able to autoland: the aircraft will follow the GS until touchdown and it will end up high.

I've never seen this so widespread in FSX o P3D. Why does that happen so often in MSFS?

Flying mainly in Europe, I have not come across this problem. Never had a problem with autoland

 

1 hour ago, Jeeeno said:

As per title: I found that many sceneries in MSFS (also some payware) have ILS issues.

For example, the localizer is offset where it should not be, or more importantly in almost 90% of sceneries, glideslope and PAPI are way off. If you follow GS until touchdown you'll end up very very high and miss the touchdown zone. 

This happens also in airports where there are CATIII approaches, so where you should be able to autoland: the aircraft will follow the GS until touchdown and it will end up high.

I've never seen this so widespread in FSX o P3D. Why does that happen so often in MSFS?

Can you give some example airports where this is a problem? (For the localizer). I can check. Some real world localizers are deliberately offset for a variety of reasons, though the approach charts will usually have a note to indicate when this condition exists.

It is not uncommon for the visual approach slope indicator and electronic glideslope to not correspond. You will see notes to that effect on a lot of r/w approach charts. 

1 hour ago, Jeeeno said:

As per title: I found that many sceneries in MSFS (also some payware) have ILS issues.

For example, the localizer is offset where it should not be, or more importantly in almost 90% of sceneries, glideslope and PAPI are way off. If you follow GS until touchdown you'll end up very very high and miss the touchdown zone. 

This happens also in airports where there are CATIII approaches, so where you should be able to autoland: the aircraft will follow the GS until touchdown and it will end up high.

I've never seen this so widespread in FSX o P3D. Why does that happen so often in MSFS?

Could you name some examples? I did a lot of ILS and RNAV approaches in the past few weeks and can't remember a single one that was wrong.

As someone who has played around with the SDK, creating a few custom airports, I can tell you that making ILS approaches work properly and match the real world takes a bit of effort and care.

I can't say for certain how most of MSFS default (non-bespoke) airports were created, possibly programmatically, but way back before MSFS was released there was talk of the default airport creation being outsource to a well-known scenery developer, who employed "temp labor" to accomplish that task. Given that a LOT of default airports have incorrect names, ICAO codes, runway locations etc. it is not at all surprising that some ILS approaches don't work either.

The OP is correct in what he says and it has been a well documented long standing problem in every flight simulator I have used.

However, I don't see too many issues with the localiser these days and of course some are designed to be offset. I flew into Nice Côte d’Azur last night and that is an example of one such by design however the real problem has always been the glideslope. In particular, near the runway threshold. The data often becomes ridiculous around there and is often totally unreliable. I had one during a hand flown approach recently that would have had me land way past the touch down zone.

Things like the PMDG planes (other developers are available😉) still autoland fine though and I suspect they are doing something on their end with their planes to bypass the erroneous FS glide slope readings. I may have read that somewhere over the years or just made it up in my head. I can't see how else their autolands are so accurate though.

It's always been something that has needed fixing.

Are using Navigraph or not? As I believe most of the issues with ILS is often caused by the default navdata and when the scenery makers may not always input the ILS freqs needed to make it work. 

4 minutes ago, Zangoose said:

Are using Navigraph or not? As I believe most of the issues with ILS is often caused by the default navdata and when the scenery makers may not always input the ILS freqs needed to make it work. 

It has nothing to do with what he's talking about. The problem exists everywhere. The MSFS, P3D, FSX, FS2002, FS2000, FS98.....all of them had issues with this system. It's always been a problem as long as I can remember.

Edited January 7, 20233 yr by Jazz

Another sign that you can look aout for when you fly is that the PAPI often does not correlate with the glideslope. I was on a glideslope the other night and had four reds. Go figure.

 

I'm so used to this nonsense now I learned to ignore it all from about 500 feet above and just fly visually.

The problem is caused by the magdec.bgl file not being updated.

Updated Magnetic variation data for FS9 FSX-P3D-MSFS
Magnetic variation data calculated by FS9 date back from 1988 and have significantly changed
(several degrees in some part of the world). Those used by FSX, P3Dv1-4 and MSFS are identical
and date back from 2009. P3DV5 uses more recent data (around 2018-2019).
FS9, FSX, MSFS and P3D (all versions) calculate magnetic variation using a special
latitude/longitude table that is contained in the MAGDEC.BGL file. Details on its structure and the
way it is used by the simulator are available in this FSDeveloper Wiki article.
The new provided MAGDEC.BGL table corrects all magnetic variations for FS2004 & FSX-P3D-
MSFS based on values calculated from the WMM2020 model at epox January 1st, 2023 and
coded to the special normalized representation used in the MAGDEC.BGL file.
Some additional details on how the simulator use the different "magnetic variation" data
(MAGDEC.BGL file, ILS, navaid and airport magnetic declinations as defined in BGL files) can be
read in this article.
This package contains updated (2023) MAGDEC.BGL files for both FS2004 and FSX-P3D-
MSFS as well as a test and information program (Sim MagVar Calculator).

1 minute ago, SierraHotel said:

The problem is caused by the magdec.bgl file not being updated.

Updated Magnetic variation data for FS9 FSX-P3D-MSFS
Magnetic variation data calculated by FS9 date back from 1988 and have significantly changed
(several degrees in some part of the world). Those used by FSX, P3Dv1-4 and MSFS are identical
and date back from 2009. P3DV5 uses more recent data (around 2018-2019).
FS9, FSX, MSFS and P3D (all versions) calculate magnetic variation using a special
latitude/longitude table that is contained in the MAGDEC.BGL file. Details on its structure and the
way it is used by the simulator are available in this FSDeveloper Wiki article.
The new provided MAGDEC.BGL table corrects all magnetic variations for FS2004 & FSX-P3D-
MSFS based on values calculated from the WMM2020 model at epox January 1st, 2023 and
coded to the special normalized representation used in the MAGDEC.BGL file.
Some additional details on how the simulator use the different "magnetic variation" data
(MAGDEC.BGL file, ILS, navaid and airport magnetic declinations as defined in BGL files) can be
read in this article.
This package contains updated (2023) MAGDEC.BGL files for both FS2004 and FSX-P3D-
MSFS as well as a test and information program (Sim MagVar Calculator).

I vaguely remember this has something to do with some of the issues one may encounter but does this affect the glideslope or just the localiser? I can see it only being the cause of some of the localiser issues.

I could very easily be wrong on that though.

The P.A.P.I. problem is something else entirely, i.e. caused by the pilot's position in the cockpit. P.A.P.I are fixed in place so depending on what aircraft you are flying your view will be completely different. I would only ever rely on this as a (very) rough guide. The ILS, being a radio signal, is also fixed in place, so as you approach the rwy FF is where your aircraft coincides with the ILS radio signal.

Edited January 7, 20233 yr by SierraHotel

25 minutes ago, Jazz said:

I vaguely remember this has something to do with some of the issues one may encounter but does this affect the glideslope or just the localiser? I can see it only being the cause of some of the localiser issues.

I could very easily be wrong on that though.

Magdec applies to runway alignment with magnetic north, if it's never been updated on some sims it could be as much as 12 degrees out!! here is where to get the latest updated magdec.bgl, and instructions as to where it should go..................... Happy Landings (again 😉

https://www.aero.sors.fr/navaids.html

Edited January 7, 20233 yr by SierraHotel

The LOC are usually pretty good.   As mentioned before,  the GS especially when near the runway is ridiculous. If you follow it, you will wind up with a long landing 80% of the time. 

Edited January 7, 20233 yr by Bobsk8

Just now, Bobsk8 said:

The LOC are usually pretty good.   As mentioned before,  the GS especially when near the runway is ridiculous. If you follow it, you will wind up with a long landing 80% of the time. 

Must admit I don't have this happen, although most of the airports I use are handcrafted and have the ILS aligned.