Definition

The temporary change of usage limitation of movement areas established for the taxiing of aircraft or parts thereof.

Notes:

this scenario includes the notification on usage limitation of one or more full taxiways (could be all the taxiways at the airport);
this scenario includes notification on usage limitation of taxiway portions, provided the taxiway elements exist in the baseline data (see the specific assumptions for baseline data);
this scenario requires a graphical view of the taxiways and taxiways portions;
more than one taxiway can be included only if the usage limitation conditions (closed, exceptions, parts) applies equally to all taxiways. Otherwise, separate NOTAM shall be issued;

Event data

The following diagram identifies the information items that are usually provided by a data originator for this kind of event. Note that the flight and/or aircraft categories branch is optional, but can be more than once.

EBNF Code

input = "airport designator" ["airport name"] \n
("taxiway designator" ["affected taxiway description"] {"affected taxiway element"}) {("taxiway designator" ["affected taxiway description"] {"affected taxiway element"})}\n
("conditional for" | "closed, except for" |  "prohibited for" | "allowed for")
(["operation"] ["aircraft"] ["flight"] ["PPR time" ["PPR details"]]) {["operation"] ["aircraft"] ["flight"] ["PPR time" ["PPR details"]]} \n
["reason"] "start time" "end time" [schedule] \n
[note].

The table below provides more details about each information item contained in the diagram. It also provides the mapping of each information item within the AIXM 5.1.1 structure. The name of the variable (first column) is recommended for use as label of the data field in human-machine interfaces (HMI).

Data item	Description	AIXM mapping
airport designator	The published designator of the airport where the taxiway is located, used in combination with other elements in order to identify the taxiway(s) and/or taxiway portion(s) concerned.	AirportHeliport.designator
airport name	The published name of the airport where the taxiway is located, used in order to identify the taxiway(s) and/or taxiway portion(s) concerned.	AirportHeliport.name
taxiway designator	The published designator of the taxiway concerned. This information is used in combination with the airport designator/name in order to identify the affected taxiway(s) and/or taxiway portion(s)	Taxiway.designator
affected taxiway description	In case of a partial closure, a textual description of that taxiway portion concerned should be provided	Taxiway.availability.ManoeuvringAreaAvailability.annotation (see ER-02)
affected taxiway element	In case of both a portion of and a full taxiway being affected by the temporary limitation, the exact geometry of the taxiway portion affected should be precisely identified by specifying the concerned taxiway elements The application shall allow graphical display and selection of taxiway(s) and/or taxiway portion(s); The operator shall be the one manually selecting all the portions to be closed.	TaxiwayElement(s) identified as explained in the Data Encoding Rule ER-01.
conditional for	The description of one or more operations, which are permitted under special conditions, usually a prior permission requirement	Taxiway.availability.ManoeuvringAreaAvailability.operationalStatus with value 'LIMITED' and Taxiway/..Usage.type with value 'CONDITIONAL' TaxiwayElement.availability.ManoeuvringAreaAvailability.operationalStatus with value 'LIMITED' and TaxiwayElement/..Usage.type with value 'CONDITIONAL'
closed, except for	Taxiway is closed, except for operations explicitly identified in the input data.	Taxiway.availability.ManoeuvringAreaAvailability.operationalStatus with value 'LIMITED' and Taxiway/..Usage.type with value 'RESERV' TaxiwayElement.availability.ManoeuvringAreaAvailability.operationalStatus with value 'LIMITED' and TaxiwayElement/..Usage.type with value 'RESERV'
prohibited for	The description of one or more operations that are prohibited for during the event duration.	Taxiway.availability.ManoeuvringAreaAvailability.operationalStatus with value 'LIMITED' and Taxiway/..Usage.type with value 'FORBID' TaxiwayElement.availability.ManoeuvringAreaAvailability.operationalStatus with value 'LIMITED' and TaxiwayElement/..Usage.type with value 'FORBID'
additionally allowed for	The description of one or more additional operations that are available for a specific purpose during the event duration.	Taxiway.availability.ManoeuvringAreaAvailability.operationalStatus with value 'OTHER:EXTENDED' and Taxiway/..Usage.type with value 'PERMIT' TaxiwayElement.availability.ManoeuvringAreaAvailability.operationalStatus with value 'OTHER:EXTENDED' and TaxiwayElement/..Usage.type with value 'PERMIT'
operation	The specific type of operation concerned by the usage limitation update.	Taxiway/..Usage.operation and TaxiwayElement/..Usage.operation
aircraft	The description of one or more aircraft (such as "helicopter") types are permitted or prohibited (depending on the limitation type) during the event duration.	Taxiway/ManoeuvringAreaAvailability/Usage/..selection/..AircraftCharacteristics and TaxiwayElement/ManoeuvringAreaAvailability/Usage/..selection/..AircraftCharacteristics Only the following AircraftCharacteristics properties are allowed to be used in this scenario: type, engine, wingSpan, wingSpanInterpretation, weight, weightInterpretation.
flight	The description of one or more type of flight categories (such as "emergency") that are permitted or prohibited (depending on the limitation type) during the event duration.	Taxiway/ManoeuvringAreaAvailability/Usage/..selection/..FlightCharacteristics and TaxiwayElement/ManoeuvringAreaAvailability/Usage/..selection/..FlightCharacteristics Only the following FlightCharacteristics properties are allowed to be used in this scenario: type, rule, status, military, origin, purpose.
PPR time	The value (minutes, hours, days) of the prior permission request associated with a permitted operation.	Taxiway/ManoeuvringAreaAvailability/Usage.priorPermission with uom attribute and TaxiwayElement/ManoeuvringAreaAvailability/Usage.priorPermission with uom attribute
PPR details	Additional information concerning the prior permission requirement.	Taxiway/ManoeuvringAreaAvailability/Usage.annotation with propertyName='priorPermission' and purpose='REMARK' TaxiwayElement/ManoeuvringAreaAvailability/Usage.annotation with propertyName='priorPermission' and purpose='REMARK'
reason	The reason for the taxiway usage limitation.	Taxiway.availability.ManoeuvringAreaAvailability.annotation with propertyName='operationalStatus' and purpose='REMARK'. Note that the property "warning" of the ManoeuvringAreaAvailability class is not used here because it represents a reason for caution when allowed to operate on the taxiway, not a reason for a closure.
start time	The effective date & time when the taxiway limitation starts. This might be further detailed in a "schedule".	Taxiway/TaxiwayTimeSlice/TimePeriod.beginPosition, TaxiwayElement/TaxiwayElementTimeSlice/TimePeriod.beginPosition, Event/EventTimeSlice.validTime/beginPosition and Event/EventTimeSlice.featureLifetime/beginPosition
end time	The end date & time when the taxiway limitation ends.	Taxiway/TaxiwayTimeSlice/TimePeriod.endPosition, TaxiwayElement/TaxiwayElementTimeSlice/TimePeriod.endPosition, Event/EventTimeSlice.validTime/endPosition and Event/EventTimeSlice.featureLifetime/endPosition also applying the rules for Events with estimated end time
schedule	A schedule might be provided, in case the taxiway's usage is effectively limited according to a regular timetable, within the overall limitation period.	Taxiway.availability.ManoeuvringAreaAvailability/Timesheet/... and TaxiwayElement.availability.ManoeuvringAreaAvailability/Timesheet/...according to the rules for Schedules
note	A free text note that provides further details concerning the taxiway limitation.	Taxiway.availability.ManoeuvringAreaAvailability.annotation with purpose='REMARK'

Assumptions for baseline data

It is assumed that the related Airport/Heliport BASELINE Timeslice covering the entire duration of the event exist and have been coded as specified in the Coding Guidelines for the (ICAO) AIP Data Set. In addition:

the information about each Taxiway concerned already exists in the form of a Taxiway BASELINE TimeSlice, which contains as a minimum:
1. designator,
2. type (ex: EXIT, FASTEXIT, etc), and
3. association with the AirportHeliport;
If taxiway portions are concerned, it is assumed that they are encoded in BASELINE TaxiwayElements, including their horizontal extent (geometry) to enable graphical selection.
It is assumed that the following principle has been followed for the encoding of BASELINE Taxiway.availability and TaxiwayElement.availability data (as available in the BASELINE data):
1. the operationalStatus has the value 'NORMAL' (meaning that the facility operates with nominal parameters) for all Taxiway.availability and/or TaxiwayElement.availability that are part of the BASELINE data;

Data encoding rules

The data encoding rules provided in this section shall be followed in order to ensure the harmonisation of the digital encodings provided by different sources. The compliance with some of these encoding rules can be checked with automatic data validation rules. When this is the case, the number of the encoding rule is mentioned in the data validation rule.

Identifier	Data encoding rule
ER-01	The temporary limitation of a taxiway or portion thereof shall be encoded as: a new Event with a 'BASELINE' TimeSlice (scenario='TWY.CLS', version='2.0'), for which a PERMDELTA TimeSlice may also be provided; and a 'TEMPDELTA' TimeSlice for each affected Taxiway feature, for which the "event:theEvent" property points to the Event instance created above; if present in the baseline data, a 'TEMPDELTA' TimeSlice for each affected TaxiwayElement feature, for which the "event:theEvent" property points to the Event instance created above; Important Note: the application shall support the operator in order to automatically select the TaxiwayElements that are concerned with a graphical view, as indicated in the figure below. By default, intersections are supposed to remain unaffected, unless explicitly specified as closed.
ER-02	The textual description of the taxiway affected portion, if provided, shall be encoded as part of the Taxiway TEMPDELTA as availability.ManoeuvringAreaAvailability.annotation and purpose='DESCRIPTION' E.g. “intersection TWY A and TWY B”, "between RWY 08L/26R and TWY J", etc.
ER-03	First, all the BASELINE availability.ManoeuvringAreaAvailability (with operationalStatus='NORMAL'), if present, shall be copied in the Taxiway and TaxiwayElement (if applicable) 'TEMPDELTA' (see Usage limitation and closure scenarios). Then: for each Taxiway TEMPDELTA coded and for each TaxiwayElement TEMPDELTA, an additional availability.ManoeuvringAreaAvailability element having shall be added having: operationalStatus='LIMITED' if the taxiway usage is "conditional for", "closed, except for", "prohibited for"; operationalStatus='OTHER:EXTENDED' if the taxiway usage is "allowed for".
ER-04	If the taxiway usage is "conditional for" specified operations, flight and/or aircraft categories, then all specified limitations shall be encoded as ManoeuvringAreaUsage child elements with type='CONDITIONAL'.
ER-05	If the taxiway is "closed, except for" specified operations, flight and/or aircraft categories, then all specified limitations shall be encoded as ManoeuvringAreaUsage child elements with type='RESERV'.
ER-06	If the taxiway usage is "prohibited for" specified operations, flight and/or aircraft categories, all specified limitations shall be encoded as ManoeuvringAreaUsage child elements with type='FORBID'.
ER-07	If the taxiway usage is "allowed for" specified operations, flight and/or aircraft categories, all specified limitations shall be encoded as ManoeuvringAreaUsage child elements with type='PERMIT'.
ER-08	If a unique flight or aircraft is specified as part of the condition, they shall be encoded as one ConditionCombination with logicalOperator='NONE'. Otherwise, each pair of flight and aircraft shall be encoded as one ConditionCombination with logicalOperator='AND'.
ER-09	If PPR time is specified, the uom attribute shall also be specified.
ER-10	If the limitation concerns only a discrete schedule within the overall time period between the "start time" and the "end time", then this shall be encoded using as many as necessary timeInterval/Timesheet properties for the ManoeuvringAreaAvailability (with operationalStatus='LIMITED' or 'OTHER:EXTENDED') of all affected Taxiway and TaxiwayElement TEMPDELTA Timeslice(s). See the rules for Event Schedules.
ER-11	The system shall automatically identify the FIR where the AirportHeliport is located. This shall be coded as corresponding concernedAirspace property in the Event
ER-12	The AirportHeliport concerned by the closure shall also be coded as concernedAirportHeliport property in the Event.

Examples

Following coding examples can be found on GitHub (links attached):

to be developed

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