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For Runway Direction, PANS-AIM requires some basic properties as part of the minimum AIP data set. These are

designator, true bearing, threshold, ...

The diagram below shows the AIXM classes, including the relevant data types, needed to encode that information:

The RunwayDirection class is used for coding the data of one of the two landing and take-off directions of a runway for which attributes like Take-off Run Available (TORA), Take-off Distance Available (TODA), Landing Distance Available (LDA), etc. may be defined.

A Runway can have one or more related runway directions. In general, it will have two runway directions. A runway direction will be associated with maximum one runway.

For each runway direction, at least a designator and its true bearing has to be specified. Also, a magnetic bearing may be specified.

Furthermore, also the related threshold (i.e. reference to RunwayCentrelinePoint) has to be encoded.

The RunwayDeclaredDistance class is used to code TODA, TORA, ASDA, LDA, rejected TODA, etc. and also a displaced threshold.

Runway Direction Designator

The RunwayDirection.designator is the full textual designator of the landing and take-off direction. 

Examples: '09', '09L', '09R', '09C', '09T', etc.

It may carry up to 16 characters. However, the naming convention of the RWY direction designator shall comply with that of the RWY designator (see also Basic Data for Runway (and FATO)).

Example: RWY designator is specified as '08L/26R', thus the RWY direction designators shall be '08L' and '26R' respectively.

See also coding rules below.

Runway Bearing

For each RunwayDirection, a trueBearing shall be defined. The true bearing is the measured angle between the runway direction and True North at a given position. For the true bearing, also the trueBearingAccuray shall be provided.

In addition, a magneticBearing may also be coded. The magnetic bearing is the measured angle between the runway direction and Magnetic North at a given position.

The figure below shows an example for a runway bearing for runway direction 08L and 26R.


In AIXM 5, the RunwayCentrelinePoint class is used to encode operationally significant positions on the centre line of a runway direction. A typical example is the runway threshold.

ICAO, Annex 14, Volume 1[1] defines the threshold:

The beginning of that portion of the runway usable for landing.

The threshold centre line point for a runway direction is not necessarily the physical start of the runway and may be displaced for operational reasons.

In case of runway threshold, the RunwayCentrelinePoint.role is assigned the value 'THR' (threshold) or 'DISTHR' (displaced threshold, see also Declared Distances).

Consequently, the geographical location for the threshold or displaced threshold is coded using the ElevatedPoint class. In general, a threshold will have an assigned elevation value.

If appropriate, the geoidUndulation at a threshold position will be coded.

For the elevation and the geoidUndulation, a verticalAcurracy shall be provided.


In AIXM 5 the verticalAccuracy refers to both the elevation and the geoidUndulation.

Hence, if the verticalAccuracy is coded for elevation but the accuracy for the geoid undulation is not known, this should be put into a corresponding Note.

A threshold is related with at maximum one RunwayDirection.

A RunwayCentrelinePoint may have a designator, used to uniquely identify it at an aerodrome/heliport.

The figure below shows an example for a threshold for runway direction 08L and a displaced threshold for 26R. The coded role for 08L will be 'THR' and for 26R 'DISTHR'.

To encode terminal procedures (SID, STAR, IAP) it may be necessary to reference the runway centre line point (especially the THR) as procedure fix. Therefore, the RunwayCentrelinePoint can be encoded as DesignatedPoint.

Other runway centre line points

Apart from the threshold position, the ICAO Annex 15 also requires the publication of the runway end, in each of landing and take-off direction.These can be encoded as RunwayCentrelinePoint with role='END'.

The physical end of a runway in one landing and take-off direction is also the physical start of the opposite runway direction. The model allows encoding both START and 'END' roles. This could lead to duplication of the data. Based on how the data is published in the AIP and how it is actually used, it is recommended to encode only the 'END' point for each RunwayDirection and to not encode the 'START'. Only for runways that are used in a single direction (such as runway 18 at Frankfurt, EDFF), both the 'START' and the 'END' need to be encoded on the same RunwayDirection, because the other direction is just not encoded.

Following the same logic of avoiding duplication, the 'MID' point should be encoded only for the runway direction with the lower designation number.

The following table provides a complete list of values the RunwayCentrelinePoint.role attribute can take:

'START'Physical start of a runway direction.
'DISTHR'Displaced threshold.
'TDZ'Touchdown Zone
'MID'The mid point of the runway
'END'Physical end of a runway direction

Start of take off run


Also known as "departure threshold":

'LAHSO'Point indicating Land And Hold Short Operation location
'ABEAM_GLIDESLOPE'The point perpendicular to the Glideslope Antenna on the Runway Centreline.  Also known as the Aiming Point.

The point perpendicular to the Precision Approach Radar (PAR) Antenna on the Runway Centreline.


The point perpendicular to the Elevation Antenna on the Runway Centreline.


The point perpendicular to the Touchdown Reflector (TDR) on the Runway Centreline.


The point perpendicular to the Runway End Reflector (RER) on the Runway Centreline.


Coding Examples

Coding examples can be found in the AIP Data Set - Specimen (DONLON):

No.DescriptionXPath Expression



Runway direction, threshold, and declared distances

//aixm:RunwayDirectionTimeSlice[@gml:id ='RDN_EADD_09L'] |

//aixm:RunwayCentrelinePointTimeSlice[@gml:id ='RCP_EADD_09L']



Runway direction (incl. TDZ elevation), threshold, and declared distances (incl. displaced threshold).


The data published in ICAO DOC 8216 for AIP specimen DONLON and in the corresponding eAIP specimen provided by Eurocontrol have been altered
in order to have an example for the encoding of a displaced threshold.

//aixm:RunwayDirectionTimeSlice[@gml:id ='RDN_EADD_27R'] |

//aixm:RunwayCentrelinePointTimeSlice[@gml:id ='RCP_EADD_27R']



Runway direction, threshold, and declared distances//aixm:RunwayDirectionTimeSlice[@gml:id ='RDN_EADD_09R'] |

//aixm:RunwayCentrelinePointTimeSlice[@gml:id ='RCP_EADD_09R']



Runway direction, threshold, and declared distances//aixm:RunwayDirectionTimeSlice[@gml:id ='RDN_EADD_27L'] |

//aixm:RunwayCentrelinePointTimeSlice[@gml:id ='RCP_EADD_27L']



FATO direction//aixm:RunwayDirectionTimeSlice[@gml:id ='RDN_EADD_FATO_03'] |



FATO direction, threshold, and declared distances//aixm:RunwayDirectionTimeSlice[@gml:id ='RDN_EADD_FATO_21'] |

//aixm:RunwayCentrelinePointTimeSlice[@gml:id ='RCP_EADD_FATO_21']

RCP-EX-05Start Run for declared Distances from TWY B//aixm:RunwayCentrelinePointTimeSlice[@gml:id ='RCP_EADD_TWY_B']
TWY-EX-01Taxiway B//aixm:TaxiwayTimeSlice[@gml:id ='TWY_EADD_B']
GLN-Ex-01Guidanceline for Taxiway B//aixm:GuidancelineTimeSlice[@gml:id ='GLN_EADD_TWY_B']


1. 1

ICAO, Annex 14, Aerodromes, Volume 1, Seventh Edition, July 2016

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