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ILS and PAPI do not match

Posted: Mon Oct 21, 2024 10:21 am
by dkreiskott
Hello Jean Luc,

In the last few months I've noticed that the ILS and PAPI are never correct when landing. I've tried a few things with the airports because I was looking for the error there. But thanks to Herve's tools I was able to rule that out.

Could it be a software error? The screenshot shows the problem.

Image

Re: ILS and PAPI do not match

Posted: Mon Oct 21, 2024 3:38 pm
by balu69
Hello Dieter
How does the landing work?
Could it be that the camera position has changed?

Re: ILS and PAPI do not match

Posted: Tue Oct 22, 2024 7:57 am
by dkreiskott
Hi Stephan,
I don't use camera tools. And I haven't changed the views either. I've already revised the airports in line with the current AIRAC's regarding ILS. But that didn't solve the problem either.
An approach using ILS also works, but sometimes it means that you touch down too late.
That depends on the airport.

The screenshot isn't from my home cockpit either. I use a separate computer for software development and have a separate Prepar3d license there.
So the problem exists on both computers.

Re: ILS and PAPI do not match

Posted: Tue Oct 22, 2024 11:39 am
by bbruechmann
Dieter, Captain Ingo would say "the PAPI lights doesn´t matter at an precison instrument approach via ILS" The ILS glideslope rules it out, only." The PAPI lights are made for non-precision visual approaches.
That´s said, i don´t mean that the PAPI and ILS GS never match, but they don´t have to, nessecarely.

Re: ILS and PAPI do not match

Posted: Tue Oct 22, 2024 1:21 pm
by jeehell
Depending on the airport the glide path antenna and the PAPI location may not match in p3d. Also if you use add-ons that can be a problem.
Also I am not convinced p3d PAPI & ILS are correct, for instance the ILS over an ellipsoidal earth is actually not a simple trig computation which I believe p3d does...

Re: ILS and PAPI do not match

Posted: Wed Oct 23, 2024 11:21 am
by dkreiskott
@Bernd
I agree with you that the ILS and the PAPI don't have to match exactly. But the deviation that I've documented here is very large.

As JL already describes, who knows whether the PAPIs are in the right place. As far as I know, you can't adjust that.

Nevertheless, I've seen the problem with the ILS so far and have therefore updated the airport. In this extreme case, however, it didn't leave me alone. What I only noticed later is that the developer of the scenery (ENAL) lowered the airport from 70 feet to 36 feet. I don't know why you do something like that.

If you correct the airport height, the PAPI and ILS almost match.