Approaches that aren't runway specific (i.e. VOR-A)?

[Guest tmetzinger]

Hi Terry,Is it possible to place multiple RNW entries in an approach in the same way as one does in a SID? Failing that, is it possible to have an approach WITHOUT a RNW defined at all?I'm trying to write a procedure for the KPDX VOR-A approach, but I'm sure the technique would be the same for all lettered approaches. At PDX I can use RNW 21 since the approach would come in to that threshold, but at other airports there may not be a runway threshold in line - often it's the VOR colocated at the field.The other problem I'm trying to code is an approach where the Missed Approach Point is well before the airport - there's one at KSFO and there are others. Basically the way the approach would be flown would be in LNAV/VNAV until the missed approach point, and then hand flown from that point or earlier as the LNAV/VNAV path should transition to the missed approach at that point.Best wishes,

[Guest stang]

Howdy>>Is it possible to place multiple RNW entries in an approach in the same way as one does in a SID?It might help to know what aircraft you are working with but anyway, an approach is designed for one runway although it can have multiple transitions. I don't think multi runways for an approach is possible.>>Failing that, is it possible to have an approach WITHOUT a RNW defined at all?Approaches have to be assigned to a particular runway so I don't see how that is possible. A STAR on the other hand can be assigned multiple runways.>>I'm trying to write a procedure for the KPDX VOR-A approach,I guess I don't understand. That approach is for 07L from what I see.>>The other problem I'm trying to code is an approach where the Missed Approach Point is well before the airport - there's one at KSFOThe LDA PRM RW 28R approach? Off hand I don't see where that one would be programmed any different than any other approach.RegardsTerry

[Guest tmetzinger]

Terry, thanks, but...A lettered approach is not associated with a particular runway, it is almost always used to circle or manuever visually to a runway. PS there's no runway 7 (L or R) at Portland (KPDX). This approach would cross close enough to the Runway 21 threshold so using it for the RNW works. The problem on the SFO LDA DME 28R approach and the PRM version is that pilots are not allowed to miss the approach past DARNE. If you can't land visually when you reache DARNE you have to start the right turn and climb right then, NOT after crossing the runway 28r threshold. If you code it "normally" the airplane is going to end up flying over the airport in a missed approach - a no-no on this procedure.If it were possible, coding for the SFO LDA DME 28R would look something like:...FIX BATKE FIX MIUKE FIX DARNE HDG 30 INTERCEPT RADIAL 35 FROM NAVAID SFO TRK 25 INTERCEPT RADIAL 060 FROM NAVAID OAK HOLD AT FIX SALAD....So the problem is not coding the approach, it's coding the missed that's difficult.One possible way to work around this issue for both situations would be to code it as a STAR instead of as an approach, then manually select the runway. It would just have the procedure popping up in the wrong spot on the FMC.I understand that the PMDG (what I'm referring to) and other FS products can't match the complexity of the real world. I suspected that the PMDG required a runway to be defined for every approach, but I was just wondering if I was missing anything in the syntax. Thanks!

[downscc 1,327]

I've been coding the PRM approaches as if they were the standard approach... the chief difference being pilot decisions, whereby the missed approach begins earlier than the runway. I don't worry about it since a missed approach can be initiated at anytime for many reasons. Now I'm making assumptions about the FMC behavior, including the ability to hit the GA button early and have it respond correctly. I'll have to try this when I get home. Good point.As for VOR-A approaches, I've assumed they're deleted because they usually include a procedure turn (even if there are NoPT transitions available). I'd do the same thing you're suggesting if I were to add one, by assigning it to a runway and treating all other runways as circling approaches. Now I am wondering how the FMC responds if one shoots an ILS with a circling to land at a different runway, which is a pretty standard thing to do at some airports. Something else to try when I get home. Interesting.

[Guest tmetzinger]

Most PRM approaches are just like normal ILS in that if you get a wave off you climb immediately but generally don't make any turns until you are at or past the runway threshold. This one (LDA PRM 28R) at SFO is such that you HAVE to be able to complete the approach visually after DARNES, and if you don't have that ability you go missed and turn way before reaching the airport. Come to think of it, it may be moot if FS9 doesn't have that localiser installed. I need to check that.The problem I foresee with the VOR-A/B/C type approaches will occur when the lettered VOR approach course doesn't cross a runway threshold - the calculated LNAV path for the final segment will be off, since it will be from the last fix to a runway threshold and not to the VOR or something else - I think though that in that case one could add a new waypoint to be the MAP just before the RNW waypoint.

[Guest tmetzinger]

Well that particular LDA isn't in the NAVDATA file, and I don't think it's in the scenery either, so it's moot for now until somebody adds it.I got your KSTL updates by the way - we do the SID/STARS similar in some ways, except I will take an ILS/LOC procedure and use one ILS approach procedure and hard code all the altitude constraints so that pilots flying the ILS with the glideslope out can use LOC/VNAV, and of course if the glideslope is active then they use APPR and the constraints dont matter anyway. I do that because ILS approaches are ALWAYS called ILS approaches even when the GS is out of service - the clearance you get from ATC is cleared ILS 12, glideslope inop.I only code LOC approaches in the SID/STAR file if they get a separate chart. My goal is to have the approaches I see in the FMC match the charts I see in my EFB.I like the way you split the STARs too based on the landing direction - I'm going to start incorporating that into my custom versions as well.Best Wishes,

[woodreau 0]

I was wondering if there has been any more information regarding this as I have an approach that I am trying to code in PMDG, and it is a circling approach. Once you get down to MDA you execute a visual procedure (a 180 degree right turn) to find the airport 6 miles behind you. and if you do not have the airport in sight, you continue the turn to make a 360 and climb back up the valley following the localizer backcourse.I did find a copy of the approach coded in the NAVDATA webpage in the SID/STAR page, but it actually isn't coded correctly and I am using that as a starting point and at the same time adding my coded interpretation of the approach.This is the approach I am trying to code.And this is what I have come up with: But I haven't had a chance to run it through the PMDG FMS yet.I went ahead and paired it with Rwy 8 - I'm thinking it will cause the course line to be drawn back to Rwy 8 from AB but in real life the approach can be flown to either Rwy 8 or Rwy 26.Thanx in advanceand thank you for the "How to write PMDG procedures" pdf - that document has been a great help.Steve WongPentium III 850Mhz - FS2004 - 768MB RAM - nVidia GeForce FX5200 - 120GB IDE HD - 1TB NAS