transitionlevel.xml

The transitionLevel.xml file is used to calculate the transition level (TRL) and the transition altitude (TA) for each airport.

The transition level.xml file is located in the fir/ directory

Root Elementtrl
Elementairport
AttributeFormatRemarks
icaostringairport icao code, selects every airport starting with this (partial) ICAO code
defaultbooleanthe default transition level to use

The icao attribute can be a full 4 character ICAO airport designator or a partial code which will select multiple airports.

example ICAO attribute

  • “le” will select all Spanish airports starting with “le”
  • “egl” will select all airports starting with “egl”
  • “eddf” will only select EDDF Frankfurt
Elementqnh
AttributeFormatRemarks
taintegerTransition Altitude (TA)
trlintegerTransition Level (TRL) in hundreds of feet
minfloatminimum QNH value
maxfloatmaximum QNH value

The TRL (transition level) is choosen using the current QNH and comparing it with the minimum and maximum QNH values.

example

<trl>
	<!-- TA=5000 -->
	<airport icao="EKCH" default="true">
		<qnh ta="5000" trl="55" min="1032" max="1060"/>
		<qnh ta="5000" trl="60" min="1014" max="1031"/>
		<qnh ta="5000" trl="65" min="996"  max="1013"/>
		<qnh ta="5000" trl="70" min="978"  max="995"/>
	</airport>
	<airport icao="EKRK">
		<qnh ta="5000" trl="55" min="1032" max="1060"/>
		<qnh ta="5000" trl="60" min="1014" max="1031"/>
		<qnh ta="5000" trl="65" min="996"  max="1013"/>
		<qnh ta="5000" trl="70" min="978"  max="995"/>
	</airport>
	<!-- TA=3000 -->
	<airport icao="EKYT">
		<qnh ta="3000" trl="35" min="1032" max="1060"/>
		<qnh ta="3000" trl="40" min="1014" max="1031"/>
		<qnh ta="3000" trl="45" min="996"  max="1013"/>
		<qnh ta="3000" trl="50" min="978"  max="995"/>
	</airport>
</trl>

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