Glideslopes and PAPIs are still incorrect

[dectenor1]

ISSUE DESCRIPTION

Description of the issue:

Glideslopes and PAPIs are still incorrect in the sim and don’t match with each other.

Following the ILS to over the threshold results in the aircraft crossing the threshold at the incorrect height as can be seen by comparing with the TCH (Threshold Crossing Height) on the charts.

FREQUENCY OF ISSUE

How often does this occur for you (Example: Just once, every time on sim load, intermittently)?

Pretty much every airport in MSFS 2024, whether default, handcrafted, or third party.

REPRODUCTION STEPS

Please list clear steps you took in order to help our test team reproduce the same issue:

1. Follow the ILS - easiest using autopilot.

2. Observe the RA crossing the threshold.

3. Compare to the charts.

4. Also compare the glideslope to the PAPIs

YOUR SETTINGS

If the issue still occurs with no mods and add-ons, please continue to report your issue. If not, please move this post to the User Support Hub.

What peripherals are you using:

[PC Only] Are you using Developer Mode or have you made any changes to it?

No

[PC Only] What GPU (Graphics Card) do you use?

RTX4090

[PC Only] What other relevant PC specs can you share?

Not relevant

MEDIA

*Please add a screenshot or video of the issue occurring.
*
**EGPH
**
Above glide, but 3 reds..

**EDDN
**
Crossed threshold at 50ft RA but glideslope showing 1 dot and half too low. Also PAPIs showing 2 red 2 white whilst glide a dot and half too low.

Correct TCH should be 53ft RA, as shown below, so glideslope incorrect.

**HUEN
**
Low on glide but 3 whites - doesn’t make sense

Perfectly on glide, crossing threshold at 95 ft RA - with 4 whites!!!

TCH should be 54ft RA as shown below. So yet again glideslope incorrect.

I could go on with more examples, but it is clear that the glideslopes are still completely wrong in MSFS 2024.

It is really disappointing as this has been an issues since the release of 2020 coming up 6 years ago and is still unfixed.

There was some hope in these beta notes that the glideslopes had been fixed closed to the runway but still sadly not.

[Bishop398]

I am not able to reproduce many of these cases. Are you using stock data or Navigraph? Navigraph data will not necessarily have these corrections to match the sim scenery.

EGPH PAPI Non-Repro:

EDDN TCH (listed as 53ft):

Some other random spot checks:

DIAP TCH (listed as 50ft):

EGLC TCH (listed as 34ft):

LTAH TCH (listed as 60ft):

RKCH TCH (listed as 57ft):

WABB TCH (listed as 50 ft):

The one case I was able to reproduce was HUEN, which we can investigate (it may be a source data issue). As far as the PAPI go, our changes in the sim radio code were limited to glideslope deviation math, which mostly caused large swings in deviation near the last 100 feet or so. Additionally, for the stock navdata, we have also used some heuristics to try to align the ILS laterally, and we also have aligned the antennae height to the airport scenery to improve TCH.

As there is no data for PAPI in the worldwide ARINC, there are no changes to the position of these lights at this time. There is no programmatic way for us to determine via the navdata if the PAPI are intended to be coincident or not, aside from having a human check the chart for every ILS at every airport in the world.

For the last two items, if you are not using stock navdata, you will not be a recipient of these improvements (as they are necessarily part of the definitions of the ILS positions in the navdata itself).

[IslandSimPilot]

One thing worth remembering is that, speaking simplistically, the PAPIs are calculated to the cockpit height of the largest aircraft that lands at that airfield, which I doubt is the Vision Jet. It’s actually eye-to-wheel height, but in any event they are set for a cockpit that’s much higher than the one you’re sitting in.

[DementedCorn327]

PAPI incorrect placement is a different issue than the glideslope one and is not part of the ILS fix implemented in the SU6 Beta.
Feel free to contribute to the existing report: PAPI and VASI lights have wrong placement, causing long landings, or are missing

[dectenor1]

Many many thanks for looking into this.

I was using the default sim navdata (I think).

I only use navigraph to update third party aircraft such as Fenix, PMDG etc.

They were third party airports however. Other than HUEN which is default in the sim but handcrafted, so I guess that technically is third party.

I will try again at those airports but with default scenery.

It would be so great to clear up this issue and why the glideslopes are off at so many third party airports.

Who is responsible for the glideslopes?

Is it the navdata? Therefore the navigraph data could be wrong? But surely it’s also navigraph data that the default sim uses?

Do the glideslopes get overridden by third party airports? And they have their own glideslopes that ignore the navdata?

Or are the glideslopes from navigraph, but third party airports are at a slightly different altitude to what navigraph expects thus causing them to be inaccurate?

It really is a pain because obviously lots of people use third party scenery and it’s so annoying that the glideslopes are incorrect. Please not I’m not apportioning any blame here, it would just be so great to find a way of making them be accurate.

I watch a lot of videos/streams and the inaccurate glideslopes are such a major cause of people’s bad landings in my opinion.

I see so many landings where the aircraft never crosses the threshold at the correct height, because of the inaccurate glideslopes and/or inaccurate papis.

Either both are inaccurate but match each other, or both are inaccurate and neither match each other, or one of them (usually the glideslope) is inaccurate, but the papis are correct, but they don’t match and people don’t know which to follow etc. Quite a mess!

Whichever combination it so often leads to the aircraft not crossing the threshold at the correct height.

Then it either leads to slams because you try and land on the markers even though you’re twice as high crossing the threshold as you should be, or extremely long potentially dangerous landings because you’re simply too high when you reach the runway and to get a smooth landing you need to go all the way to the end of the touchdown zone and beyond.

It would be so so great to get this cleared up and make third party scenery devs aware of what they need to do if indeed they are responsible.

Or if it is something even the user can tweak in some config file of the scenery before we use that airport, or in the navdata that somehow we can make the runway height match that of the scenery, if indeed that it is what’s causing the issue.

Anyway, this post is already too long, but many thanks for looking into it.

[Bishop398]

@dectenor1

Who is responsible for the glideslopes?

The installed sim navdata (whether stock or Navigraph), or the scenery developer if they have included their own ILS navaids.

@dectenor1

Do the glideslopes get overridden by third party airports? And they have their own glideslopes that ignore the navdata?

That is something they can do, yes, if they desire. It is not something they have to do.

@dectenor1

But surely it’s also navigraph data that the default sim uses?

No. The sim uses worldwide AIRAC data provided by LIDO, not Navigraph (whose data comes directly from Jeppesen).

@dectenor1

Or if it is something even the user can tweak in some config file of the scenery before we use that airport, or in the navdata that somehow we can make the runway height match that of the scenery, if indeed that it is what’s causing the issue.

The only way to do this would be to make your own scenery mod that would sit on top of the handcrafted airport, and how to do that is a bit complex of a topic to describe in a forum thread.

In general, I imagine the guidelines for scenery developers would look something like this for best TCH:

• If you don’t plan on including your own ILS, then you should maintain runway end heights to be the same as the stock sim
• If you plan on changing runway end heights, then you should include your own ILS that match the new heights

@dectenor1

Then it either leads to slams because you try and land on the markers even though you’re twice as high crossing the threshold as you should be

With proper landing technique this should not be the case. Keep in mind that the ILS receiver location in a plane IRL can vary greatly; the actual gear-to-ground height of a 747 vs a Vision Jet over the threshold will be 10s of feet different from each other for a given ILS, which for a standard 50ft TCH could eat up a reasonable percentage of that distance.

The pilot should be transitioned to a visual approach at minimums. It’s good to keep the beam in mind as a reference point, but the sight picture rules all after minimums. If the pilot is slamming it down then they’re not paying attention to the runway sight picture and are too focused on the instruments. The exception to this would be the rare CAT III autoland, but the touchdown zone is long for a reason. You don’t have to slam it in on the numbers and the autopilot will not try to.

Real life ILS that are not Cat III will also naturally vary some feet vertically as the calibration is not as precise or done as frequently. A standard Cat I could be like 10 feet, say.

Hope that all helps!