Database formats

I am using the GNS430 database of airports.txt and navaids.txt in a research flight simulator. Is there any documentation of the format of this database? I notice that the range of all NDBs is given as 195 and there does not seem to be any way to distinguish VORTACs and TACAN from VOR. Is this information available elsewhere in Navigraph databases?
Many thanks
DaveSheffield

Hi Dave,
we may not forward any none public technical documentation for the file-formats. The GNS430 is a part of X-Plane, therefore please contact Laminar Research to get the correct documentation but I have looked into your report:

  • the distance 195Nm is a default value - I will look, if I can change it with real-values in one of the next cycles
  • there is no possibility to sign a VOR as TACAN/VORTAC or VOR - there is only the possibility to define a VOR with or without DME - sorry, for that we can´t do anything

Hope that helps a little,
Richard

Hi Richard


Many thanks for your prompt reply. I fully understand the commercial protection issues. Are you able to tell me if my attachment is in the right ballpark? Even without VOR/TAC and Tacan, it’s a fantastic database for a research flight simulator (not Xplane).
Best regards
Dave

Looks good Dave :+1:

Some additional comments:
Runway #6: 0 = no ILS available, 1 = ILS available
Navaid #11: 0 = autotune enabled, 1 = autotune disabled

But pssst, all is top secret and only for your eyes :smile:

Cheers
Richard

There are no trade secrets from our side (X-Plane) when it comes to the old format.
In fact, it’s not even ours. It’s the old Digital Aviation format which dates back to the days of FS9. It was used in X-Plane at some point simply because I drank a beer with Hans, the developer at Digital Aviation, and found it was a pretty darn good solution for its time.
It was used on the Flight 1 Mustang, Flight 1 ATR, Digital Aviation Fokker and Digital Aviation Cheyenne, the Coolsky DC9 and others before I brought it into the X-Plane world, following the 2012 Aerosoft conference where Hans and me had the abovementioned beers.

Anyway, X-Plane has no copyright or anything like that on the data format. The document used to be publicly available on the Digital Aviation support forum, which now has disappeared form the internet. So you might be able to find a copy by searching for it under the term “Digital Aviation FMS format” rather than X-plane format, because that’s what it is.

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Hi Philipp,

Welcome to our new forum. It is a pleasure to hear from you again.

Thank you for those data insights.

Cheers
Ian

What would be really helpful is:

  1. To include the NDB range as NDB transmitter power varies considerably
  2. To define the type of navaids as: ADF, VOR, VOR/DME, ILS, ILS/DME, VORTAC or TACAN, particularly for chart displays.
    In all aspects, the database is excellent.

I just happen to have a copy of this on one of my hard drives :grinning:
FMS_Format.zip (8.9 KB)
Might be of some interest.
Stephen.

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Many thanks for the document. It confirms my original guesses and also that only ADF, DME and VOR beacons are included in the nav database and ILS beacons are included in the runways database, but no VORTAC or Tacan, which is a pity. Also, the runway heading is in integer degrees M whereas a floating-point value would be more helpful for ILS (although it is possible to calculate the actual QDM from the lat/long of the endpoints of each runway). Finally, I can’t find any reference to the magnetic variation used for the databases, although there are other methods of estimating magnetic variation.

Note that LR recently changed the way X-Plane stores its navdata, hense there are 3 versions of navdata for different versions of XP:

  • XP10
  • XP11.41 (supported only to the end of the year, cycle 2014).
  • XP11.50 and later

The user created GNS430 folder that you may have placed in \Custom Data is intended for addon aircraft eg. FF757/767/777 and CRJ200 ect. that still use legacy data type, eg. “Digital Aviation FMS format”.

As a X-Plane user you may not realise that X-Plane stores the VOR ‘Station Declination of Record’ in it’s earth_nav.dat files. Note: LR is continually updating XP so XP11.50 now uses a slightly different Spec: NAV1150-Spec ect.

Note: VOR ‘Station Declination of Record’ is only the same as Magnetic Variation on the day the VOR is comissioned (or re-swung), read this old thread on X-Plane.org for more info.

As you probably know the Magnetic North pole is constantly change position, and the local Magnetic Variation changes (correct term = Declination).

In X-Plane Magnetic Variation is coded as per Ben’s post here.

Also Have a look at these old posts on the X-Plane Dev Blog:
Note especially what Phillip has to say on the subject:

Hope that has been of some help.
Stephen (cessna729).

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Many thanks for the tips. Strictly, I don’t use XP - my simulator is a university engineering flight simulator with all the code in C (see http://www.wiley.com/legacy/wileychi/allerton). I do use OSG for the IG and have recently used XP11 as a stand-alone IG which works well. For magnetic variation, I mostly use UK airports and the value only changes twice a year. The NOAA software contains the information I need and there is a C version of the code. Dave

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