Watching the included video im getting the feeling this is an ATR bug but i will check anyway just to make sure its not affecting the rest of the stock AC.

10 minutes ago, Stearmandriver said:

How would this be a solution?  LPV approaches have near ILS minimums; whether you're coupled or handflying at 1,000ft, if you're following incorrect guidance, the guidance is still incorrect, right?

How about that! You can pitch below GS follow follow 3 degrees and still get to MDA, or wait for Asobo fix LOL 

1 minute ago, sd_flyer said:

How about that! You can pitch below GS follow follow 3 degrees and still get to MDA, or wait for Asobo fix LOL 

Can't do that in IMC though. Might go splat. If you're flying an LPV approach to minimums in IMC, you ain't where you think you are.

1 minute ago, mryan75 said:

Can't do that in IMC though. Might go splat. If you're flying an LPV approach to minimums in IMC, you ain't where you think you are.

As long as you have geo reference approach plate in from of you can you can clearly see all fixes along flight path and missed approach point. You can drop one bar below GS. IMC or VFR works for me

3 minutes ago, sd_flyer said:

As long as you have geo reference approach plate in from of you can you can clearly see all fixes along flight path and missed approach point. You can drop one bar below GS. IMC or VFR works for me

How do you know you're one bar below if your vertical guidance is incorrect? You can't use dive and drive on a precision approach. What you're talking about would work just find on a non-precision approach, but not an LPV. I know this is sim flying and this problem wouldn't occur in real life, and depending on what you're flying, landing halfway down a 10,000-foot runway doesn't make any difference. But still.

Are you sure this isn't specific to the scenery?

2 minutes ago, mryan75 said:

How do you know you're one bar below if your vertical guidance is incorrect? You can't use dive and drive on a precision approach. What you're talking about would work just find on a non-precision approach, but not an LPV. I know this is sim flying and this problem wouldn't occur in real life, and depending on what you're flying, landing halfway down a 10,000-foot runway doesn't make any difference. But still.

Works for me under circumstances. If you aware of your approach speed vs pitch vs vertical speed you can interpolate GS that brings you close enough where you suppose pop out the cloud. Call no gyro approach or wait for Asobo fix. 

1 minute ago, Mace said:

Are you sure this isn't specific to the scenery?

That one I'm positive on. Just flew the RNAV 08 into SJU and same problem. I expect it and plan for it now.

1 minute ago, mryan75 said:

That one I'm positive on. Just flew the RNAV 08 into SJU and same problem. I expect it and plan for it now.

Is this stock TTPP?  I know there's aftermarket / 3rd party scenery for TTPP (I own it) -- but I don't know which you are using.

1 minute ago, Mace said:

Is this stock TTPP?  I know there's aftermarket / 3rd party scenery for TTPP (I own it) -- but I don't know which you are using.

There's a 3-airport pack which has TTPP, TTCP and TGPY, that's the one I'm using. But it happens in all RNAV approaches in the ATR. And the PMDG 737 has no problems with the TTPP RNAV, I've flown it 100 times.

6 minutes ago, sd_flyer said:

brings you close enough

Yeah... That's not IFR flying, at least not on a precision approach, and even in the sim probably builds negative habit patterns for if you ever do this in real life.

How about, instead of pretending this isn't a problem, we just focus on figuring out which airplanes it affects and what the solution might be?  What would be the point of acting like it isn't a problem?  For whichever planes it affects, it's a very significant bug indeed.

6 minutes ago, mryan75 said:

There's a 3-airport pack which has TTPP, TTCP and TGPY, that's the one I'm using. But it happens in all RNAV approaches in the ATR. And the PMDG 737 has no problems with the TTPP RNAV, I've flown it 100 times.

Ok, so that tells me it's the airplane (the ATR), and not the sim.  I mean if the PMDG 737 can fly an RNAV down to the correct spot (not the ARP) then it has to be the ATR airplane.

34 minutes ago, mryan75 said:

I'm pretty sure Navigraph updates the 750's data. I think if you're using Navigraph, all the navdata in the sim is Navigraph.

It is, but in different formats.  (I'm not trying to argue with you; I geek out on the satnav stuff in real life and in the sim so I've done some work with this.  Just interested in narrowing down what you've found.)

So Navigraph maintains a nav database for the base sim, and then many other formats of navdata used by different add-ons like the PMDG or FENIX (which each use a different custom format.)

Most GPSs use the base sim navdata, which, whether updated by Navigraph or not, is still in the same format with the same capabilities.  So if it was designed in a way that procedures had to use ARP elevation instead of rwy waypoint elev, that would still be the case in the navigraph updated version.

But maybe the PMS50 does use it's own navdata?  I've done these with the G1000 and not noticed the issue either though, but it's been a while .. I don't know.  It's a good find either way!  Hopefully it ends up being specific to just the one airplane...

4 minutes ago, Mace said:

Ok, so that tells me it's the airplane (the ATR), and not the sim.  I mean if the PMDG 737 can fly an RNAV down to the correct spot (not the ARP) then it has to be the ATR airplane.

Yeah it's either the ATR or the stock nav data. I'm now leaning towards the ATR.

5 minutes ago, Stearmandriver said:

It is, but in different formats.  (I'm not trying to argue with you; I geek out on the satnav stuff in real life and in the sim so I've done some work with this.  Just interested in narrowing down what you've found.)

So Navigraph maintains a nav database for the base sim, and then many other formats of navdata used by different add-ons like the PMDG or FENIX (which each use a different custom format.)

Most GPSs use the base sim navdata, which, whether updated by Navigraph or not, is still in the same format with the same capabilities.  So if it was designed in a way that procedures had to use ARP elevation instead of rwy waypoint elev, that would still be the case in the navigraph updated version.

But maybe the PMS50 does use it's own navdata?  I've done these with the G1000 and not noticed the issue either though, but it's been a while .. I don't know.  It's a good find either way!  Hopefully it ends up being specific to just the one airplane...

I absolutely don't think you're trying to argue, you clearly know a lot about how the underlying data works, which I don't. I just can't figure out how they would make this mistake. I can imagine it on approaches with no runway threshold waypoint, but not on ones where there is. It's pretty weird.