En-route holding

Introduction & Background

PANS-AIM section "5.2 Aeronautical information in a standardized presentation" states:

When the AIP Data Set (as specified in 5.3.3.1) is provided, the following sections of the AIP may be omitted and a reference to the data set availability shall be provided
...
h) ENR 3.6 En-route holding;

En-route Holding is not listed as subject in PANS-AIM section "5.3.3.1.1 AIP data set", but it is part of PANS-AIM Appendix 1 (Aeronautical Data Catalogue).

ENR 3.6 En-route Holding is marked with #AIP-DS# in PANS-AIM, and hence is considered conditional data.

Page Table of Content

Basic mapping

The data elements contained in ENR 3.6 are mapped to the following main AIXM 5 features and its properties:

PANS-AIM	Description (PANS-AIM)	AIXM 5	Definition (AIXM 5.1.1)	Remarks
Identification	Identification of the holding procedure	N/A	HoldingPattern: A predetermined manoeuvre which keeps an aircraft within a specified airspace while awaiting further clearance.	AIXM 5.1.1 does not have a dedicated attribute for the Identification of a Holding Procedure. The identifier of a holding will be the designator of the SignificantPoint used as holdingPoint, i.e. the DesignatedPoint.designator or the Navaid.designator.
Fix	Identification of the holding procedure fix	HoldingPattern.holdingPoint.SegmentPoint.pointChoice.fixDesignatedPoint, or HoldingPattern.holdingPoint.SegmentPoint.pointChoice.navaidSystem,	holdingPoint: The point used to define the holding pattern.	Info In PANS-AIM ENR 3.6, the term "holding fix" is used for a "navigation aid", in contrary to "waypoint". In PANS-AIM Appendix 1, "Fix" is used for the Identification and "Waypoint" for the geographical location! There seems to be some inconsistency, also a Fix will have a geographical location and also a waypoint will have an Identification. Mapping is based on the assumption that one property is for the identification and the other for the position, regardless if it is a fix or a waypoint. The identifier of a holding procedure fix is the designator of the referenced DesignatedPoint or the Navaid
Waypoint	Geographical location of the holding waypoint	HoldingPattern.holdingPoint.SegmentPoint.pointChoice.fixDesignatedPoint. or HoldingPattern.holdingPoint.SegmentPoint.pointChoice.navaidSystem	see above.	See also info above. The geographical location of the holding waypoint is location of the referenced DesignatedPoint or the Navaid. Info Note that PANS-AIM has specific accuracy requirements for a holding waypoint which in AIXM 5 are coded by the horizontalAccuracy attribute of the referenced DesignatedPoint or the Navaid.
Inbound track	The inbound track of the holding procedure	HoldingPattern.inboundCourse	inboundCourse: The radial, course or bearing of the inbound leg as it pertains to a holding pattern.
Turn Direction	Direction of the procedure turn	HoldingPattern.turnDirection	turnDirection: An indicator of the turn direction (such as left, right or either) in an aerial manoeuvre performed by aircraft during holding operations.
Speed	Maximum indicated airspeed	HoldingPattern.speedLimit	speedLimit: Restricted speed for containment in a smaller pattern during holding operations.
Level - Minimum holding level	Minimum holding level of the holding procedure	HoldingPattern.lowerLimit and HoldingPattern.lowerLimitReference	lowerLimit: The minimum vertical distance (measured from a specified reference) allowed for all aircraft categories, at all defined speeds, operating in a holding pattern. lowerLimitReference: The reference surface (Mean Sea Level, Ground, standard pressure, etc.) used for determining the value of the lower limit of a holding pattern.
Level - Maximum holding level	Maximum holding level of the holding procedure	HoldingPattern.upperLimit and HoldingPattern.upperLimitReference	upperLimit: The maximum vertical distance (measured from a specified reference) allowed for all aircraft categories, at all defined speeds, operating in a holding pattern. upperLimitReference: The reference surface (Mean Sea Level, Ground, standard pressure, etc.) used for determining the value of the upper limit of a holding pattern.
Time/distance outbound	Time/distance value of the holding procedure	HoldingPattern.outboundLegSpan.endTime.HoldingPatternDuration.duration, or HoldingPattern.outboundLegSpan.endDistance.HoldingPatternDistance.length	outboundLegSpan: Outbound leg ends at a choice of a time, a length or a defined end point. HoldingPatternLength: Representation of a span for a holding pattern that can be defined using either duration, distance or as outbound to a Significant Point. duration: The duration of the holding pattern outbound leg. length: The length of the holding pattern outbound leg.	in AIXM 5 there is a third option that is not mentioned in PANS-AIM: the limitation of the outbound distance by another SignificantPoint. This is coded via HoldingPattern.outboundLegSpan.endPoint.
Special holding entry procedure	Textual description of the Special VOR/DME entry procedure	HoldingPattern.instruction	instruction: Operational instructions that must be observed when flying the holding pattern.

Additional mapping (Controlling Unit)

The data items defined for the Controlling unit are mapped to the following main AIXM 5 features and its properties:

Note

The controlling unit may also be derived from the airspace the holding is located in (in case the airspace has an assigned controlling unit).

PANS-AIM

Description (PANS-AIM)

AIXM 5

Definition (AIXM 5.1.1)

Remarks

Controlling unit

(

InformationService.clientHolding

and
InformationService.serviceProvider,

)

or

(

AirTrafficControlService.clientHolding

and

AirTrafficControlService.serviceProvider

)

clientHolding:

The holding pattern for which the information is provided.

serviceProvider:

The Unit that provides the Service.

Note

In AIXM 5, there is no direct association between an HoldingPattern and its Controlling Unit, hence the mapping has to be done via the corresponding Service for the HoldingPattern, which is provided by a Unit. IN PANS-AIM there is no requirement/property to code the type of Service that is provided.

Controlling unit - Name

Indication of the controlling unit

(

InformationService.serviceProvider,

or

AirTrafficControlService.serviceProvider,

)

and

Unit.name

name: The full textual name of a unit. This name must be established according to the rules specified by International Civil Aviation Organisation (ICAO), and specifically in the official language of the country, transposed into the Latin Alphabet where necessary.

Controlling unit - Frequency

The operating frequency/channel of the controlling unit

(

InformationService.radioCommunication,

or

AirTrafficControlService.radioCommunication

)

and

(

RadioCommunicationChannel.frequencyTransmission,

and

RadioCommunicationChannel.frequencyReception,

)

or

RadioCommunicationChannel.channel

radioCommunication: The radio frequency on which the service is provided.