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

Attribute	Format	Remarks
Root Element	trl
Element	airport
icao	string	airport icao code, selects every airport starting with this (partial) ICAO code
default	boolean	the 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

Attribute	Format	Remarks
Element	qnh
ta	integer	Transition Altitude (TA)
trl	integer	Transition Level (TRL) in hundreds of feet
min	float	minimum QNH value
max	float	maximum 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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