With help from several sources, I've finally managed to bang together a working custom RNP (AR) approach in the new PMDG navdata format, including RF legs etc.  Figured I'd show it here as a proof of concept; it can be done, and in the end it isn't even all that hard, there's just a few conventions you need to understand.
 

This is a real-world procedure, the first RNP (AR) approach ever built anywhere in fact - which made it seem appropriate to experiment with - to RW26 in PAJN.  I had an approximation of this working in the old navdata, but let's just say there's no longer a need to approximate.  I used the 777 for testing but am interested to see how the 737 will do it when that gets the navdata update, as the 777 won't really fly an approach speed schedule in VNAV, you have to speed intervene (my understanding is that is accurate to the real aircraft.)

Takeaways: the new navdata is basically real-world, and the new flight guidance tracks it almost perfectly ( just an occasional twitch of such short duration it doesn't affect anything.)  The autopilot actually got a little lazy following the flight guidance down low though, and so short final on the coupled approach wasn't quite lined up with the runway.  When I hand flew it though and manually stayed in the flight guidance, it dropped me on a perfectly aligned final.
 

 

Edited July 23, 20241 yr by Stearmandriver
Thought better of including the video.

Thanks for posting this, it's really interesting. I used to love trying the RNP approaches that someone built for the PMDG 737 in FSX and it's great to see this. Such interesting airports in Alaska, I love Juneau, Petersburg and Wrangell amongst others.

On 7/23/2024 at 4:33 AM, Stearmandriver said:

there's just a few conventions you need to understand.

And they are?  Thanks.

-B

cannot wait until they bring this to the 73. 

I’m trying it on the Fenix which will fly RNP Approaches. Looking at RWY 26 I see no approaches listed save for visual.  How do you unleash the AR approach?

TIA,

-B

44 minutes ago, btacon said:

I’m trying it on the Fenix which will fly RNP Approaches. Looking at RWY 26 I see no approaches listed save for visual.  How do you unleash the AR approach?

TIA,

-B

It's a special procedure, so only certain airlines are allowed to fly it, some approaches up in Alaska are also proprietary to Alaska Airlines. Won't show in Navigraph, you'd need the plate and to modify the navdata (hence the proof of concept)

30 minutes ago, mspencer said:

It's a special procedure, so only certain airlines are allowed to fly it, some approaches up in Alaska are also proprietary to Alaska Airlines. Won't show in Navigraph, you'd need the plate and to modify the navdata (hence the proof of concept)

Got it. But some AR approaches turn up in Navigraph data do they not?

-B

19 minutes ago, btacon said:

Got it. But some AR approaches turn up in Navigraph data do they not?

-B

Yeah plenty of them do, PSP and the Rocky Mountain airports usually have a few.

20 minutes ago, btacon said:

Got it. But some AR approaches turn up in Navigraph data do they not?

-B

Most do that are not proprietary to specific airlines. A good one to try for testing is the RNP Z approach to runway 13R at Palm Springs KPSP

30 minutes ago, btacon said:

Got it. But some AR approaches turn up in Navigraph data do they not?

-B

KDCA has a couple of them: RNAV (RNP) RWY 01 and RNAV (RNP) Z RWY 19.

I think someone may have beat you to it as this video from a few weeks ago contains an approach that doesn't seem to be available in the sim or in Navigraph. But it's good to see that it's possible. 

 

38 minutes ago, RNAVV19R said:

I think someone may have beat you to it as this video from a few weeks ago contains an approach that doesn't seem to be available in the sim or in Navigraph. But it's good to see that it's possible. 

 

 

1 hour ago, btacon said:

Got it. But some AR approaches turn up in Navigraph data do they not?

-B

PSP is a good suggestion.  The RNP 33 into PANC is public and does a 360 to lose altitude in the bowl if you choose the right transition.  But probably the most interesting public approach I know is into Khatmandu landing north... Runway 02 maybe?  It reminds me of some of ours; uses RF segments to weave through terrain. Just requires more terrain clearance than some of ours because of public TERPs.

3 hours ago, btacon said:

And they are?  Thanks.

-B

Naming conventions that allow the FMC to recognize the procedure as the correct type, and leg termination types mostly.  Waypoint Type codes in some cases as well.  Basically, read the real ARINC-424 specs and it tells you what you need to know.  Was a fun little project to learn... Now I have a couple dozen to build haha.

49 minutes ago, RNAVV19R said:

I think someone may have beat you to it as this video from a few weeks ago contains an approach that doesn't seem to be available in the sim or in Navigraph. But it's good to see that it's possible. 

 

Quoted you in the wrong response sorry.  But yeah, that's a cool one too... Just a visual, not really a full approach w GP legs or RF segments I think.  Good to have something to hold onto for that maneuver to 01R for sure though!

2 minutes ago, Stearmandriver said:

Quoted you in the wrong response sorry.  But yeah, that's a cool one too... Just a visual, not really a full approach w GP legs or RF segments I think.  Good to have something to hold onto for that maneuver to 01R for sure though!

It's an RNAV Visual. It has an RF leg between KLAUS and SQIRL. Pretty cool approach. 

Here is the chart: