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Guest RoSPA_David

What Approach Will ATC Assign You?

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This has been bugging me for some time now. Hi, shirley im not alone in flying using the standard ATC, nor can i be the only one flying IFR. I currently use FSNavigator, yes im aware of the lack of updates into this program, but that is not the real issue. When flying IFR at some point, known to FS9 the ATC sparks up and lets you know your distance from the airport and the approach / transition that it has for you. Now, in some cases at larger airports you have the option to choose another approach. All this info would be handy right at the start, while filing and even planing with FSNav or whatever program you use. My question; where does FS9 get the approaches from? I considered it could be the navigraph data that i download each month, but that cant be right. This information is spoken by ATC so shirley it must have been programmed earlier. I would like to be able to view a given approach, well just have it identified prior to flight. Phew, thats my rant over. Hope someone stayed with it till the end.Kind Regards David

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FS9 gets its data from the stock simulator files.The runway ATC assigns you has to do with where you're coming from and what heading you're flying when it's time for ATC to assign a runway. It'll assign the active runway closest to you, but it also looks at an active runway with a heading closest to your heading. The type of approach is usually a simple vectors ILS. If that's not available, it takes the next best thing, etc... If you want a transition, you'll have to ask for one.If you use a flightplanner, you should be able to predict your landing runway. Or if you have a runway in mind, you should be able to manipulate your route so that you get that runway. If you want realistic routes, check out http://flightaware.com/statistics/ifr-route or http://rfinder.asalink.net/free, depending on where you fly. Input a route into the planner and then you can get a good idea of what runways to use.Of course, it helps if you know what the weather is like. Personally, I use ActiveSky and fetch a weather report for departure and destination airport before the sim is even running. And then based on that info, I start to plan my flight, departure and arrival gates, runways, route, Afcads to use if applicable, etc...

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Excellent answer, Mike. I concur, ActiveSky and the FlightAware website are two of the best resources for us simmers, and that site is totally free-of-charge. I use it all the time.

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Thanks for the quick response. I dont have an issue with runways. I understand how they are decided on, but what i really wanted to know is where the data is stored for FS to choose a transition approach. If i had this then it would be easier to plan using FSnavigator.any ideas?Regards David

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As I said, in stock simulator files. The same files that hold the stock Afcads. If you use third-party Afcads, the stock Afcads get "disabled". There are special approach files that do the same with approaches. Those files are primarily used to hardcode runway changes, such as redesignations or additions.They are of the name AP*.bgl. Each file holds information for lots of airports for a particular area. And they can be decompiled into XML. There's no user-friendly way of looking at those approaches before you run the sim. The best way to check them out is by using the default GPS receiver.One more note, for some reason ATC will not always allow you to choose a transition, even though it exists. I believe it has something to do with the type of the entry point that is used, I think I read that somewhere, but I'm not sure.

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>If you use a flightplanner, you should be able to predict your>landing runway. Or if you have a runway in mind, you should be>able to manipulate your route so that you get that runway. If>you want realistic routes, check out>http://flightaware.com/statistics/ifr-route or>http://rfinder.asalink.net/free, depending on where you>fly. Input a route into the planner and then you can get a>good idea of what runways to use.I use FSBuild to build a flighplan and flight aware or EURoute to get the appropriate routes. However, it's a guessing game what runway, hence what STAR I should get upon arrival. I can load up Activesky and determine the winds, and get a runway that lands with the headwind. Then I can plan my STARs accordingly. However, this does not always work, or the wind changes and I have to be rerouted.What is the best rule logic for predicting the landing runway for flights, sometimes a couple of hours in advance.Thanks!

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Nobody took advantage of the perfect "don't call me Shirley" op?

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Hi,Using any type of real weather you cannot reliably predict the runway that will be in use. This is also true in real life at many airports, since in addition to the unpredictable winds there are often other factors at work too, like visibility and traffic patterns that certain airports factor into the equation.So just like the real crew, you will have to be flexible. :)Hope this helps,--Tom GibsonCal Classic Propliner Page: http://www.calclassic.comFreeflight Design Shop: http://www.freeflightdesign.comDrop by! ___x_x_(")_x_x___

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Personally, I use fixed real world weather as I fly mostly short to medium haul anyway.

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LOL I so wanted to post that line from Airplane but decided to keep quiet...Rob

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As previously indicated, the approaches are encoded as part of the airport data within the AP9/APX files. The available approaches are all listed in the GPS through use of the PROC key. Runway assignment in FS9 is complex, and among other things depends on the approaches available and the prevailing visibility. A runway with ILS is generally scored very high. ATC will offer the ILS approach with vectors to final. Using the GPS, you can find another approach type or transition to use. The ATC requires you to separately request a new runway and approach (if you want to change runways). If you only request an approach related to another runway ATC will assume you will sidestep or circle to land at the runway ATC offered.ATC will not offer all transtions. In particular for ILS ATC normally won't allow transitions from a waypoint, but rather one based on a navaid.There are AFCAD files available that change runway numbering , locations, or add /delete runways. ATC will recognize the new runways, but unless the approaches are also modified, they will be visual-only runways, even if an ILS beam was added to the runway by the developer. Since the "AFCAD" program never included the ability to open or modify approaches, many developers fail to take this into account.scott s..

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"Surely", you mean?Anyhow, as mentioned the data is available in the bgl files located in the C:MiscMicrosoft GamesFlight Simulator 9Scenery folder under NamcScenery, NameScenery and NamwScenery and probably a few other places for Europe or whatever. They are basically default AFCADs and will be disregarded if 3rd party AFCADs exist for the airport(s) in your Addon Scenery folder.It would be so difficult to look/edit at all of them, however, it's easy to do. All you need is a BGL decompile program from the Avsim library (BGLXML, NewBglAnalyze, BGLComp, ect..) to open them and look to see in XML format what the approaches are there. You can edit them, but it's probably easier and safer to make addon BGL AFCADs for this purpose, as I've read that some compile the XML back to BGL with minor errors. I edited a few a year ago and it worked great, but then I saw that it can mess up certain parameters in the AFCAD, so I put them back from a back-up folder. I could've done it right and I never noticed a problem, but it's just so time-consuming. Look at the format and you'll see, it's a pain in the @ss.You can update the navdata in terms of new intersections with Facility Editor (free - Avsim library) and the PMDG Navdata update files for each airport, but it's still a hassle. I've slowly been updated each airport I fly to that hasn't been updated, but it's really only for the flight planner. I also add intersections without the PMDG Navdata files by manually converting the GPS coordinates and creating a file for Facility Editor to read. I think you can do NBD and VORs with another app, but I've yet to need to do this.As for knowing the runway ahead of time, in real life you'd never know what runway you're gonna get until close to the airport either. Yes, you could find out by asking over the ATC and getting some earlier predictions, but that could still change. You always need to be able to adapt to the change of runway assignments. I realize in a Boeing or other FMC/MCDU/GPS equipped plane that you want to program the computer to get the best approach, and having only one person doing that is tough, but you can learn to work around it. If the runway you expect and program into the FMC is wrong, then enter a hold while you change the FMC app data to fly a perfect final to the correct runway. Planes enter hold a lot for traffic and other reasons, so that's no unrealistic in this simulation. Other options are use vectors, fly by hand using the IAP only, or even pause the sim to reprogram the FMC. Personally, I'd prefer reprogramming the FMC if vectors or hand flying wasn't an option by doing it fast while on one heading to a waypoint or enter a hold. If you ask for your own approach with a transition, you'll be left alone to do whatever you want. Only instructions will be descents. Ultimately, your best plan, per real world ops, is to have all the plates for the arrival airport on hand so you can pick your approach and/or know what to do. If the approach you want isn't there, then pick one in the sim and fly the closest thing to it using the approach plate. I honestly don't think the sim knows if you fly off the IAP you asked for. To know beforehand isn't realistic, nor possible unfortunately. If you fly in the U.S., then AirNav.com has all the plates you need for free in PDF format. The non-US ones can be found in various other places, but may be very old.

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I use FlightAware all the time as well. I wish/or is there one I don't know about, that does the same thing in Europe? Scott

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Nice explanation, Chris.One concern is if choosing a different runway than the active AI are using is the possibility of conflict unless it is just to use a near parallel runway in the same general landing direction.Sometimes FS AI do strange things and at the request of users RC always chooses the runway AI are using as the highest priority by monitoring AI that are present. It is even possible that RC will change the runway assignment during early approach phases if RC chose a runway when no AI were present (based on priorities close to your description) and then AI start using a different runway.I do not know if FS ATC offers this flexibility but with any user intitiated diversion from the recommended ATC runway caution via TCAS and COM monitoring of chatter should be used.AI sometimes seem to land on a downwind final but as in the real world if the head/tail wind component is below a certain threshold other runway choice priorities may dominate based on aircraft and runway facilities.

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I didn't really proof read that, LOL.I should also mention that I use Active Sky for Wx and use the option to force the Wx to stay consistent starting 100 NMs out. This may not be realistic either, but it helps address the oddities in the sim with respect to AI and changing winds. Overall, AS is the best solution to some of those problems with changing runways do to wind.

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>LOL I so wanted to post that line from Airplane but decided>to keep quiet...>>Rob:-lol :-lol :-lol Oh, thank God someone said it! I thought I was the only one. I was about to explode holding that in.Jeff

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