Possibly inconsistent SID/STAR output in MSFS plan

[pointy56 5]

Hi Alex,

As you know I am looking at a way of improving flight plan import into PF3 to better handle SID/STAR/Approach data and have come across what appears to be an inconsistency between SID and STAR.
The attached LNM flight plan is from Washington Dulles (KIAD, BUNZZ3 SID) to Los Angeles (KLAX, STAR ANJJL4); I chose this as it has the both SID & STAR transitions as you will see here:

https://postimg.cc/ThHJnSMS

I do have a question about the way this is listed: waypoints BUNZZ and ANJLL are each shown twice - is this as expected?

My other question, about the apparent inconsistency relates to how this FP is exported in MSFS format.

Waypoint RAMAY includes the <DepartureFP> field for the end of the SID transition:

        <ATCWaypoint id="RAMAY">
            <ATCWaypointType>Intersection</ATCWaypointType>
            <WorldPosition>N38* 57' 38.56",W78* 12' 59.01",+011558.82</WorldPosition>
            <DepartureFP>BUNZZ3</DepartureFP>
            <RunwayNumberFP>30</RunwayNumberFP>
            <ICAO>
                <ICAORegion>K6</ICAORegion>
                <ICAOIdent>RAMAY</ICAOIdent>
            </ICAO>
        </ATCWaypoint>

But waypoint DNERO does not include the <ArrivalFP> field for the start of the STAR transition:

        <ATCWaypoint id="DNERO">
            <ATCWaypointType>Intersection</ATCWaypointType>
            <WorldPosition>N35* 2' 7.14",W114* 54' 16.40",+036000.00</WorldPosition>
            <ATCAirway>Q90</ATCAirway>
            <ICAO>
                <ICAORegion>K2</ICAORegion>
                <ICAOIdent>DNERO</ICAOIdent>
            </ICAO>
        </ATCWaypoint>

Is this as expected?  It seems inconsistent to me.

Here's a link to the lnmpln file:  https://filetransfer.io/data-package/X5Uqxrco#link

I really appreciate the assistance that you are kindly giving me with this activity.

Best regards,
Martin

[albar965 1,043]

Hi Martin,

thanks for the files.

23 minutes ago, pointy56 said:

I do have a question about the way this is listed: waypoints BUNZZ and ANJLL are each shown twice - is this as expected?

The initial fix for a transition and/or approach is always listed separately and consistently in the table. This is expected since these are two different procedure leg types. Always has been this way and I'd like to keep them separate.

What I don't like is that waypoints of SID/STAR entry/exit points are duplicated in the route description. But this is a change for later.

20 minutes ago, pointy56 said:

Is this as expected?  It seems inconsistent to me.

There are plenty of workarounds and all kind of forth and back to get along with MSFS' terribly buggy flight plan loading. So yes, this might look different to what you see in the table. The waypoints are added like this for MSFS to detect the transitions. LNM also has code to detect the saved transitions from MSFS PLN files.

I did not check you plan with MSFS. Let me know if it cannot load the procedures.

BTW: Your example helped me to find an issue that appeared when loading MSFS flight plans.

Alex

[pointy56 5]

Hi Alex,

Thanks for your reply.  I was merely curious about the 'duplicate' waypoints - they don't actually appear that way in an exported plan, so don't cause a problem.

I can confirm that the exported plan loads cleanly into MSFS.
But then I tried a little experiment - I manually edited the MSFS plan to add the ArrivalFP and runway details to the DNERO waypoint, and tried to load that into MSFS.
It loaded perfectly, then I realised that I had left the ATCAirway field in place on DNERO.  I tried once more with the airway removed and again it loaded cleanly.

So I guess what I am saying is that although I can probably work with the MSFS export as it currently is, I would prefer it if ArrivalFP could be added to the STAR entry point.

Oh, and I'm pleased that in some small way I helped you find a bug 🙂

Martin

PS Here are the edited flight plans if you wish to take a look: Edited MSFS plans

[albar965 1,043]

4 hours ago, pointy56 said:

I can confirm that the exported plan loads cleanly into MSFS.

Thanks for confirming.

4 hours ago, pointy56 said:

I can confirm that the exported plan loads cleanly into MSFS.
But then I tried a little experiment - I manually edited the MSFS plan to add the ArrivalFP and runway details to the DNERO waypoint, and tried to load that into MSFS.
It loaded perfectly, then I realised that I had left the ATCAirway field in place on DNERO.  I tried once more with the airway removed and again it loaded cleanly.

So I guess what I am saying is that although I can probably work with the MSFS export as it currently is, I would prefer it if ArrivalFP could be added to the STAR entry point.

I'm scared that this might break third-party programs (like ° vs. * for degree sign broke import to Navigraph Charts 😕).
This discrepancy is there for a reason, but I don't know for what, and frankly, I'm too lazy to do research now.🙃

Alex

[pointy56 5]

1 hour ago, albar965 said:

I'm scared that this might break third-party programs (like ° vs. * for degree sign broke import to Navigraph Charts 😕).
This discrepancy is there for a reason, but I don't know for what, and frankly, I'm too lazy to do research now.🙃

 

Don't worry, I can certainly work with the plan as it's currently exported -  and there's no way that I would describe you as 'lazy' 😉

Martin

Edited March 28 by pointy56
Typo

[pointy56 5]

Hello again Alex,

I've been working through a number of scenarios and have (unfortunately) come across one, similar to the above, where I think the exported plan is in error.
Here's the relevant piece of a flight plan from YSSY, using STAR LIZI9A into YMML:
Partial flight plan from LNM
I was expecting to see waypoint LIZZI flagged as the STAR entry point (ArrivalFP included), but this is not the case; you will see that LIZZI is listed as the IF for the LIZI9A procedure.
Unfortunately this means I can't match the STAR and waypoint names to identify the STAR entry point - usually this works perfectly. 
(I chose this approach as it's an example that requires the removal of a repeated character to match LIZZI (LIZI) with LIZI9A (LIZI).
Here are the LNM and MSFS flight plans for you to take a look please.
LNM and MSFS flight plans

Best regards,
Martin

[albar965 1,043]

22 hours ago, pointy56 said:

I was expecting to see waypoint LIZZI flagged as the STAR entry point (ArrivalFP included), but this is not the case; you will see that LIZZI is listed as the IF for the LIZI9A procedure.

I think this is due LIZZI being the endpoint of the airway Q29. Not sure how MSFS loads the plan if I remove the airway (or not) and put LIZZI into the STAR. Not at my flying computer now.

When loading a STAR from a PLN file, I'm only looking at the element "ArrivalFP" to identify the procedure. Then I look at the first (here ATPER) and previous waypoint (LIZZI) of the en-route/SID boundary and try to identify a transition (no transition for your example). I have to do this since other tools like SimBrief or Navigraph Charts save the format slightly different.
Then waypoints of the STAR are added from the database and not from the PLN file.
If all is done loading, I remove consecutive duplicates from the list.

Why do you want to identify an entry waypoint? This is determined by the STAR and not by the waypoint list. I completely ignore the redundant list of waypoints when loading SID or STAR. Only entries are used to find transitions.

This redundant list of wayoints is not the smartest design, IMO. X-Plane FMS contains only the procedure names and not the en-route waypoints which is much better.

Alex

 

[pointy56 5]

2 hours ago, albar965 said:

Why do you want to identify an entry waypoint? This is determined by the STAR and not by the waypoint list.

So I'll answer this question first:
As I said, I am trying to improve SID/STAR handling for the PF3 ATC program and the only input it has is the flight plan; so I need to be able to derive the STAR entry point from the flight plan.
This enables PF3 ATC to say 'Southwest 456 at Lima Zulu Zulu India descend and maintain 4 thousand, cleared to final for Lima Zulu Zulu India 9 Alpha Approach runway 26 left ...'
At present I assume that the earliest destination waypoint with an ArrivalFP element is the STAR entry point, but this doesn't allow for a transition; if I can match the ArrivalFP name with the waypoint name then I can correctly determine the entry point (I realise that it may not be a straightforward match due to how STAR names are derived, but it can be done).

I have generated a similar flight plan using SimBrief (different SID, same STAR); it includes the ArrivalFP element on waypoint LIZZI and it loads correctly into MSFS.

I appreciate that you may be reluctant to change the MSFS export to incorporate this element, but I believe I need this change for what I am trying to achieve - or is there another way?

I'm attaching a screenshot of MSFS after loading the SimBrief-generated plan, and a copy of the plan itself - you will see that LIZZI has both ATCAirway and ArrivalFP elements.
My earlier testing (above) with edited MSFS plans showed that MSFS is happy to accept waypoints with just ATCAirway, just ArrivalFP or both ATCAirway and ArrivalFP.

MSFS screenshot

SimBrief generated flight plan

Best regards,
Martin

[albar965 1,043]

Understood, hopefully 🙃. And thanks for the files. So

        <ATCWaypoint id="LIZZI">
            <ATCWaypointType>Intersection</ATCWaypointType>
            <WorldPosition>S37° 27' 2.20",E145° 38' 16.80",+012800.00</WorldPosition>
            <ATCAirway>Q29</ATCAirway>
            <ArrivalFP>LIZI9A</ArrivalFP>
            <RunwayNumberFP>27</RunwayNumberFP>
            <ICAO>
                <ICAORegion>YM</ICAORegion>
                <ICAOIdent>LIZZI</ICAOIdent>
            </ICAO>
        </ATCWaypoint>

would be the solution for a STAR without transition.

The same would apply if there is a transition like in "KPHX/08 MRBIL1.GCN V208 TBC V210 RSK.LARKS3 KDEN/34L":

        <ATCWaypoint id="RSK">
            <ATCWaypointType>VOR</ATCWaypointType>
            <WorldPosition>N36° 44' 54.20",W108° 5' 56.04",+013500.00</WorldPosition>
            <ATCAirway>V210</ATCAirway>
            <ArrivalFP>LARKS3</ArrivalFP>
            <RunwayNumberFP>34</RunwayNumberFP>
            <RunwayDesignatorFP>LEFT</RunwayDesignatorFP>
            <ICAO>
                <ICAORegion>K2</ICAORegion>
                <ICAOIdent>RSK</ICAOIdent>
            </ICAO>
        </ATCWaypoint>

I'll try to add this for the next update. Problem is that I have to juggle between all kind of add-ons and the stubborn MSFS.

I'll post a link here if I have a release candidate.

Alex

[pointy56 5]

Thank you Alex, here's hoping that you are able to find a suitable way to accomplish this without breaking things for anyone else. 🤞

Best regards,
Martin

[albar965 1,043]

Sorry, took a while. Here is a 3.0.7.rc1:

https://k00.fr/ca0o2ubp

Tested a bunch of plans with the latest MSFS beta and even complex plans load without issues.

Alex

[pointy56 5]

And I'm sorry for my delay in responding - I've been away for the past week.
I'll give it a try later, thank you Alex.

Martin