Hi , i have big issues with PAPI vs ILS /G/S ,  or G/P

Anyone else?

Seems very off.

Michael Moe

13 minutes ago, Michael Moe said:

Hi , i have big issues with PAPI vs ILS /G/S ,  or G/P

Anyone else?

Seems very off.

Michael Moe

They don't always correlate if that's what you're asking.

The PAPI is all about angle from the plane to the light sensors.... and that depends on where it is placed on the field.  When I worked at KDLH, the PAPI was in a very different place and very dissimilar to the ILS 27 angle.  We got a lot of pilots wondering about it but it says right on the approach plate. "VGSI and ILS glidepath not coincident."  VGSI or Visual Glide Slope Indicator could be a PAPI, VASI, PVASI, T-VASI etc

For an ILS to minimums or poor visibility you just follow the ILS until you break out and land basically.  I don't usually even look at the papi on an instrument approach (unless I break out of the clouds early/or see the runway early).  PAPIs are more for visual approaches imo.  And even in that case if you fly a C172 and you're following a PAPI and it's 2 reds 2 whites) you're going to land waaaay down the runway at a larger airport.  For visual conditions and VFR, in a small plane I just pick a stripe I want to land on.  If it's a really short runway (less than 3000 ft / 1000m) I'm typically aiming for the front of the first centerline stripe or the back of the numbers.

Edited November 16, 20223 yr by ryanbatc

The glideslope in MSFS is way off close to the runway, been like that since day one. If you follow it down you'll end up anywhere but at the touchdown markers (at least with airliners). Basically once you can read the PAPIs just turn off the FD and go visual from there. The PAPIs aren't 100% correct either, but at least they won't kill you like the glideslope in MSFS tries every now and then.

Thanks but the PMDG goes crazy with  warnings when stable on approach. The PFD is not agree.

Michael Moe

1 hour ago, Michael Moe said:

Thanks but the PMDG goes crazy with  warnings when stable on approach. The PFD is not agree.

Michael Moe

What kind of warnings do you get?

Warnings inside the airplane would have nothing to do with the PAPIs.  The aircraft is not aware they even exist 🙂 

10 minutes ago, Jeff Nielsen said:

Warnings inside the airplane would have nothing to do with the PAPIs.  The aircraft is not aware they even exist 🙂 

Unless the airplanes are becoming self-aware, in which case we're all in big trouble!!

I can't do that, Dave.

HAL 9000

1 hour ago, Jeff Nielsen said:

Warnings inside the airplane would have nothing to do with the PAPIs.  The aircraft is not aware they even exist 🙂 

We try to find out first what is the nature of the problem, he's mentioning 'warnings" if you noticed " PMDG goes crazy with  warnings when stable on approach."

From there, we can determine what might be the issue. For sure there are no GPWS calls related to PAPI or VASI.

Let's give this guy an opportunity to explain what he finds "crazy" and what he thinks is wrong with the PFD. 

I did a lot of airports in FSX, and always used slew mode to track the ILS from where the signal was supposed to be stable in to the the threshold.   You can also check out the visual PAPI or what have you that way.

 

scott s.

.

 

 

As Ryan wrote PAPI not necessarily alight with glide slope. Note glidslope angle can vary per ILS approach

 

Here is more food for a brain

https://pilotworkshop.com/tips/dont-fly-the-papi/

I wonder if the issue is an actual misplacement of the glide or PAPIs (GP angle) for that matter, by a 3rd party scenery.  That has happened before.  While it will not be perfectly in line with the PAPIs, it shouldn't be grossly out of whack either, even when charted.  That may be what he's running in to.  Hard to tell without knowing what airports he's running in to the issue at.

2 hours ago, Jeff Nielsen said:

I wonder if the issue is an actual misplacement of the glide or PAPIs (GP angle) for that matter, by a 3rd party scenery.  That has happened before.  While it will not be perfectly in line with the PAPIs, it shouldn't be grossly out of whack either, even when charted.  That may be what he's running in to.  Hard to tell without knowing what airports he's running in to the issue at.

I think since the ILS antennas are in front of the runway threshold, the glideslope ends up targeting the antennas instead of the touchdown markers. That‘s more a problem with the MSFS way of designing glideslopes than a problem of placemnent of the ILS.
Keep in mind that‘s my educated guess, I never dev‘ed sceneries.

Question is : ILS or PAPI, which one will bring you to the touchdown marks ? …quite a dilemma in short final

Pierre

5 minutes ago, Fiorentoni said:

I think since the ILS antennas are in front of the runway threshold, the glideslope ends up targeting the antennas instead of the touchdown markers.

LLZ antennas for an ILS approach are located on the opposing end of the runway (hence the ability for an autopilot to track it during roll-out). G/S antennas roughly abeam the aiming point markers (usually co-located with DME and the PAPI installation).