revision: May 2017

This file contains the configuration for the FIR and sets the public release date.

The config.fir file is located in the fir/ directory.


Element Attribute Format Comment
fir FIR definition
id string FIR identification - must be unique ICAO 4 letter designator
name string FIR name
country string country ISO code (2 letter code)
date integer date defined as YYYYMMDD, AIRAC cycle date at which this FIRDEF will be released
revision integer revision number (00-99), allows for intraday or intra AIRAC cycle updates

Note: As the revision date is read before the revision number, unless multiple revisions are required on the same day the revision number should always be 1


The origin point is the coordinate of the centerpoint of all the maps. Internally all latitude and longitude coordinates are transferred to a cartesian X/Y format in nautical mile. If you use X/Y values instead of lat/lon in a map definition, this is the origin point for these X/Y coordinates.

The <origin> element requires 1 <point> element.

Parent Element Attribute Format Comment
origin origin element, only one instance allowed, contains one point element
point latWGS84origin point latitude
lonWGS84origin point longitude

Track Correlation

This element describes the way tracks are correlated with a specific flight plan.

The classic method uses a discrete Mode A code (a.s.a. Squawk Code) to link a track to a flight plan.
Non discrete codes are Mode A codes ending with two zeroes (1000 7000 2000 1200 …) and cannot be used to correlate a flight plan.

Modern systems use the Aircraft Identification (BDS20) received from the onboard Mode S transponder. Currently only certain ANSP's 1) (Air Navigation Service Providers) use Mode S correlation enabling them to assign the non-discrete Mode A code 1000 to certain tracks which are fully Mode S transponder equipped. This also requires full Mode S radar coverage.

Element Attribute Format Comment
trackcorrelation Track Correlation method to use
method string
A use discrete Mode A code only
S use Mode S Aircraft Identification if transponder is Mode S, else use Mode A code


Magnetic Variation to use for the FIR.

Element Attribute Format Comment
magvar valuefloat -180 to 180
magvar valuestring “auto”

Note that Magnetic variation East declinations are represented by positive numbers (rotated clockwise); West declinations are represented by negative numbers. If you do not want magnetic variation to show in your maps (so magnetic north points straight up), you may use the “north” tag to indicate whether you wish true north or magnetic-north to show as straight-upwards at the centre of your FIR/preset. If the string “auto” is provided, instead of a number, the FIR will automatically calculate the magnetic variation for each possible latitude/longitide in your FIR. Note that FIR-wide settings for magnetic-variation may be over-ridden for each ATC or preset within the FIR; the above settings are used anywhere where the setting is not over-ridden. To convert from a true bearing to a magnetic bearing you deduct the magnetic-variation. If it is a west declination you are deducting a negative number which is the same as adding. For an east declination you are deducting the variation. To put it another way “West is Best. East is Least”.


Default preset to load if not specified in atc.xml

Element Attribute Format Comment
northvaluestring“mag” or “true”
north autorotateboolean“true” or “false”

Allows FIR-wide choice between magnetic-north upwards or true-north upwards; map projections from polar lat/lon coordinates to flat screen coordinates mean that this will only be correct at the middle of the FIR or preset.

If autorotate is set “true”, north upwards will apply at the centre of each preset. If autorotate is “false”, presets will NOT be automatically rotated; instead, the map will stay in the default orientation for the whole FIR, which will typically be with true-north pointing upwards at the centre of the FIR. This setting will make little difference for FIRs at equatorial/tropical latitudes, but for FIRs with higher northerly or southerly latitudes the map projection means that north changes direction on-screen either east or west of the middle of the FIR/preset.

The default setting is for magnetic-north to be upwards, and autorotation set true if not specified otherwise.


Default preset to load if not specified in atc.xml

Element Attribute Format Comment
preset defaultstring name of default preset


Default SDD theme to load if not specified in atc.xml

Element Attribute Format Comment
theme defaultstring name of default theme


Default SDD label to load if not specified in atc.xml

Element Attribute Format Comment
label defaultstring name of default label


Set if RVSM is used in this FIR.

Element Attribute Format Comment
rvsm enabledstring true or false


Set the default range used for observer or staff connections

Element Attribute Format Comment
range defaultstring 1 - 2500


Example of a config.fir file:

<fir id="EBBU" name="Brussels FIR" country="BE" date="20150402" revision="01">
	<!-- system center point - will be used as X=0 Y=0 in Cartesian system -->
		<point lat="N05053491100" lon="E00429086400"/>
	<!-- track correlation method to use -->
	<trackcorrelation method="S" />
        <!-- RVSM airspace -->
	<rvsm enabled="true" />
	<!-- default preset -->
	<preset default="default" />
	<!-- Magnetic Variation -->
	<magvar value="3.2" />
	<!-- default theme -->
	<theme default="canac2" />
	<!-- default label -->
	<label default="canac2" />
	<!-- default range (OBS) -->
	<range default="250" />


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