PAPI and VASI lights have wrong placement, causing long landings, or are missing

I’ve been wondering why I’m always seeing four red lights on short final, and I’ve figured it out. When they exist in MSFS, the visual glide slope indicators (VGSI) such as PAPI and VASI are almost always placed too far down the runway. They are also often missing or incorrectly configured (2 box vs 4 box, right side vs left side).

Focusing on placement down the runway, the MSFS standard of PAPI placement 1000’ from the threshold causes an improperly high glidepath and a long landing on shorter runways. However, many short runways (2500-4000’ in length) in the real world use a PAPI location that is only 400-800’ from the threshold. This can cause a differential of threshold crossing height (TCH) of up to 40’, but even more simply, we can assume that the PAPI location is the desired touchdown location. In the cases of incorrect placement, touching down 700’ farther down the runway, for example, will take the aircraft out of the preferred “first third” landing zone of the runway, possibly even halfway down the runway in some shorter-runway cases.

Here are some in-game examples, using raytracing distance to the runway threshold and setting the nominal eye height to the both the in-game PAPI TCH and that of the correct TCH, as indicated in the airport/facility directory (if the lights were correctly placed).

Here is Williamsport, PA, Runway 12 on the in-game PAPI, which produces a TCH of 65’:

This is 20’ higher than the correct TCH of 45, as pictured here (note where the 2-bar PAPI should be located, 325 closer to the threshold, as verified in both photogrammetry and Google Earth):

Here is the airport/facility directory entry to back this position:
KIPT AFD with text

Here is KAUN Runway 7. In-game TCH is 62’:

The correct TCH at KAUN 7 is 21’, due to a PAPI that is a whopping 600’ closer to the threshold in real life compared to the in-game counterpart. Here’s the result:

Even though I have MANY more, here’s the last example in Chatham, MA, with an in-game TCH of 53’:

This is the perspective from a correct RL TCH of 39’, due to a PAPI that is 380’ closer to the threshold in real life:

Finally, and this could warrant a topic on its own, but if I’m on an instrument approach and upon break out, see a 4-bar PAPI on the left, when it’s supposed to be a 2-bar PAPI on the right, that’s cause for a go-around because the fact it’s different than what I briefed on the approach briefing. A mis-identified VGSI could mean I’m approaching the wrong runway or at the wrong airport. This can happen on a visual approach as well.

If Asobo is going for realism, teaching pilots to get the correct sight picture, establish the correct glidepath, to land in the correct touchdown zone, and to roll out within the remaining runway length, this all needs to be fixed.

MS Store version
Stock airports

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I can’t understand why this has not raised more concerns… Almost none of the PAPI lights is reliable in the default scenery. The thread owner has it explained well, but I personally think there’s something else wrong in how these PAPI’s are programmed. My general feelings is most PAPI’s in the sim tend to indicate you are low while you are right on the glide slope. This is very obvious when flying ILS approaches: when on glide slope, I usually get 3 red 1 white when still high, and 4 reds when I get close to the runway. The YouTuber and PMDG tech team member 737NG Driver has also mentioned this many times in his videos that the PAPI’s should not be trusted in this sim. Following the PAPI’s only will usually result me in landing 500-1000 ft longer. This happens both in the default airports and some add on airports. Another feeling I have is that there is a very narrow window for you to get 2 red 2 white. Even when I am 5 miles from the runway threshold, a little adjustment on the control column will result in a color change, which just feels weird. Another problem is that these PAPI’s are way too hard to see during daytime. They are not large enough or bright enough. This may also be related to the general over-brightness of the sim during the day time, which also makes the taxiway signs hard to see. I hope someone can tell me that there is an existing add on can fix this problem but apparently I couldn’t find any.


Seriously, will it ever be fixed?

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Agree that this is very annoying and would seem to be easy to fix.

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Personal Comments

I tend to cross-check with the FPM/VV since all of the FMS I fly have them, and the VASI/PAPI are usually in agreement. VV says I’m going to the TDZ markers and I get concurrence I am on slope all the way to threshold.

I would say that some Visual Approaches (as defined in an FMS capable of rendering them as a procedure leg like the NXi) would tend to show more disagreement, but that’s actually reflective of RL - as it’s calculating an absolute 3 degree slope regardless of obstruction clearance.

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On the other hand, having the VASI/PAPI too far down the runway helps avoid the giant trees at some thresholds :wink:

The PAPI or VASI may or may not coincide with the glidepath angle on an LPV approach. The original intent of my post was to address threshold crossing height (TCH) in a visual environment (which can come after the transition from an instrument approach).

Always having them so far down the runway forces some really bad habits, especially with regard to the correct “sight picture” of the runway when on final approach. I will almost always “fly under” the PAPI (three or four reds) because the glidepath, TCH, and sight picture of the runway all looks correct when doing so.


So much this!

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Interesting, I’ll have to test that. Nominally, a 3° 4-box PAPI installation should give you about 178’ of vertical play between the change in each light housing assembly (LHA) at a distance of 5nm from the installation. So you could be dead center on the 3° glidepath and have 89’ above and 89’ below before you see a change in the #2 or #3 light, respectively.

Keep in mind that’s in a static position from the installation - as you get closer, that vertical distance decreases as the angles converge. To wit, the vertical distance between LHA change at the threshold (say, 800’ from the installation) is about 5’

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The Airman’s Information Manual (AIM) 2-1-2a-4 states “The VASI is a system of lights so arranged to
provide visual descent guidance information during the approach to a runway. These lights are visible
from 3−5 miles during the day and up to 20 miles or more at night.”

In MSFS, it is difficult to see the VASI during the daytime even at 2 miles from the runway. The VASI needs to be brightened by several notches.


They are very bright, even during the day, in real life. They do not get lost in the background scenery like they do in the sim.


I worry this wont be fixed, but at least it’s nice to know that I should disregard the PAPI and just focus on the touchdown zone.

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On shorter runways for sure. Obstruction clearance is questionable, though, even when you’re on the visual glidepath in the sim.

Another issue is instrument approaches - approach lights and VGSI are part of my approach briefing. IRL, if I pop out of IMC on the approach and see an ODALS with a 4-box VASI on the left when it’s supposed to be a MALSR with a 2-box PAPI on the right, that’s a missed approach, because it could mean I’m approaching the wrong runway. This becomes even more critical on circle-to-land approaches.

I think the airport lighting database they use is 5-10 years out of date, at least for the US. I cannot, for the life of me, figure out why they can’t get a current one.


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Brief description of the issue:

the papi lights are not visible on final. Eventually they show up, but way too late. (Night time)

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ICAO or coordinates (DevMode > Options > Display position)

LPMA approaching runway 23

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Do you have the same issue if you follow the OP’s steps to reproduce it?

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Is this happening to more of you guys?
This is just the stock airport. No addon!!
Cheers Mark

This is so frustrating. I was taking off from Charlottetown airport (YYG) for the first time last week and the papi is ON the runway…


Really good, thanks for sharing! I wonder if it’s more of an angular glidepath issue in the case he illustrated than one of placement. Did he have any insight as to whether those PAPI or the antenna were set at the correct distance down the runway or anything else that might be causing the discrepancy?

Additionally some real-life VGSI and electronic glidepaths do not coincide. We see that quite often in the US, and it’s usually not more than a few feet difference in TCH, but it will be noted in the approach chart.

Either way, it definitely looks like there’s room for improvement!

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It would be nice to know Asobo opinion about this. Personally, I’ve noticed this issue since a long time, but given I’m not a rw pilot, I haven’t bothered even posting it because I wouldn’t have been even considered.

Now I’m curious.


hopefully this gets sorted, It really can’t be called a Simulator if such a massive part of flying IRL is not functioning to a correct standard.


This should be prioritized.