Programming FMC/Navigraph Data for Charted Visual Approaches

[JCEpiano 0]

Hi folks,I've been trying my best to figure this out, with little progress. I've been staring at two visual approaches that I know are often flown as a coupled LNAV/VNAV approach in the real world: KSFO - Tipp Toe Visual Approach rwy 28LKLGA - Expressway Visual Approach rwy 31Both are absolutely easy to fly if you just manually run the nav radios and all, but I do know that in the RW, they are set up by airlines to be flown to final approach by the FMC. I've tried to learn how to program approaches directly into the navigraph data, but have come short on a couple of things.For the SFO Tipp Toe, one is supposed to join the OAK-151 out of MENLO on the BSR2 arrival and proceed to 14 DME and then turn left hdg 310 to join the rwy 28L localizer. I'm sure this can be programmed into an approach in Nav Data, but the problem is that there is no actual fix that one "intercepts" such as any of the fixes on the ILS chart. Another thing I'm trying to understand is when I program the OAK151/14 into the FMC, it actually turns me right away from what should already be the OAK-151 (which you fly the whole way down the BSR2). Is this a magnetic variation or simple FSX error with the VOR's relationship to Nav Data? Thanks for any help!!

[Tabs 2,790]

I don't think I've ever heard of visuals being in the FMC database in the real world - if that exists it's almost certainly a custom thing the airline had made. I also don't know a real pilot alive who would do a coupled approach when given the visual - most like to actually handfly when they get the chance.

[JCEpiano 0]

I think specifically in the case of the Expressway visual that the coupled approach avoids pilot error (where it is extraordinarily easy to screw it up) and extra fuel costs do to missed approaches after making the turn to final too late, or being too high.

[Tabs 2,790]

At any rate, programming these things would just require the LAT/LON for the waypoints - set those up in the FIXES section of the SIDSTAR file and then build the procedure using the normal syntax. Guess you'd call it VIS 31 or something like that... it'd get treated the same way an RNAV does and you can fly it in LNAV/VNAV.

[yos233 1]

I'll do the first one for you as an example. Add anything in each respective category to the list within your KSFO file.FIXESFIX OAK16 COLOCATED OAK 151 16.1FIX OAK14 COLOCATED OAK 151 14ENDFIXESAPPROACHESAPPROACH TIPTOVIS FIX OAK16 AT OR ABOVE 5000 FIX OAK14 HDG 310 UNTIL RADIAL 282 TO FIX SFO HDG 281 UNTIL 06 FROM FIX SFO RNW 28L HDG 265 UNTIL 3000 KEEP HDGENDAPPROACHESThat should work, let me know if it doesn't.

[Buzz313th 0]

As Ryan stated....The published Visual approaches are published to aid ATC in flow control. You are expected to fly it via visual reference, as by accepting the clearance for the visual you are letting ATC know you can see the field and maintain visual traffic seperation and clear of clouds. If you look at the Tip Toe appreaoch into KSFO you will see the plate has visual reference to landmarks and geography (unlike non visual approach plates). The Nav aid references could and probably should be refrerenced from the VOR radios using the RMI or the course lines depicted on the map/ND display, and this is to just backup your position already established through visual means.If in RL your Flight Crew saw you attempting to program a visual approach into the FMC, they would probably laugh and then ask you for the controls.Then again, this is a sim and you are able to do whatever you want to make your experience more enjoyable :)If you really want to program the published visuals, then open skyvector and goto the sectional or terminal chart and drop some flightplan waypoints over the visual refrences noted from the plate. Then enter the waypoint coordinates taken from the skyvector waypoints into the FMC.JB

Edited January 19, 2012 by Buzz313th

[JCEpiano 0]

Eric, thank you very much for your work. I'll certainly give it a try, although I have already figured something out using coordinates that I will be glad to share if you're interested.Jack, thanks for your two cents as well. In the case of the charted visuals into SFO, they are actually used quite strictly because of the parallel approaches. Most aircraft off the MOD3 arrival stream are often using the FMS Bridge Visual approach which is a fully RNAV approach procedure which only airlines with major operations at SFO utilize. Although the FMS Bridge Visual is a "visual approach," aircraft are required to call the bridge and once they see it, they descend via the approach until they're over the San Mateo bridge and resume a visual approach to the runway. The Tipp Toe works the same, you're expect to call the bridge/airport before menlo, and then are cleared to fly the procedure, which requires you to intercept the localizer for rwy 28L. The reason for this is that SFO is one of the few airports that is allowed to run simultaneous arrivals with runways that are so ridiculously close. Also, the Tipp Toe facilitates traffic flow off of the BSR2 arrival so that controllers don't need to do constant traffic calls to avoid issues. As for my intention in making this request - as you can see, I'm the training administrator for the Oakland ARTCC on Vatsim. Since we have plenty of events that feature SFO, and not that many pilots who can correctly fly the Tipp Toe or the FMS Bridge Visual, I've been working on setting them up so that pilots can easily incorporate them into their FMCs and hand fly the approach once they're on short final. The other reason for going into this is because specifically on the Tipp Toe, the last three fixes of the BSR2 arrival (SKUNK, BOLDR, MENLO) should all fall on the OAK-151. Either because the OAK VOR is totally out of sorts due to some FSX issue or because of some magnetic variation issue, the Navigraph data actually places these fixes slightly west of the OAK-151. It's more like the OAK-153. That's a big difference!! So, if you manually track the OAK-151 after MENLO, the aircraft actually turns to the right to intercept the OAK-151 instead of proceeding straight as it should. This really initiated my work on this project. I hope you can understand. Finally, my interest in the LGA Expressway visual came because of a Youtube video posted by a pilot of the approach where in the comments he clearly states that it was done as a VNAV/LNAV coupled approach. On the video you can even hear the A/P being disengaged once on final. As I said, I suspect that in these more tricky approaches airlines prefer that the FMC fly it correctly rather than the pilot making a mistake because of lack of practice on the approach. Or it may just fundamentally come down to fuel efficiency.

[Buzz313th 0]

Considering that the Mag variation info in the FSX world is over 6 years old, I can see where it might be dififcult to follow a published radial and now it is a bit more clear as to why you might want to help others program the visuals to a FMC.Maybe this might help by hopefully correcting the root problem (the FSX Magnetic variation data)Below is a link that should help update that info. Credit goes to Ryan from PMDG as this link came from his post.http://www.aero.sors.fr/navaids.htmlSee if it helps to sync up the published data with FSX after modification. If it does help, then maybe you can spread the word.By the way, thanks for contributing to Vatsim. Without it, I wouldn't be simming.JB

[oskrypuch 36]

Hey, great link to the Mag Var correction site. Thanks.* Orest