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"] ("taxiway designator" ["closed_taxiway_portion_input"]) {("taxiway designator" ["closed_taxiway_portion_input"])}\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}.  

closed_taxiway_portion_input= "between" ("taxiway designator" | "runway designator" | "apron designator" | "stand designator") "and" ("taxiway designator" | "runway designator" | "apron designator" | "stand designator").

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

closed taxiway portion input

The portion of a published taxiway, specified using intersection elements between that taxiway and other taxiways, runways, aprons or stands.

Note on closed taxiway portion input:

  1. The application shall allow graphical display and selection of taxiway(s) and/or taxiway portion(s) to be closed;
  2. The HMI application should support the operator in identifying all relevant taxiways, taxiways portions and other elements that are affected by the closure and have an impact on operations. As a general rule, if an intersection has to be closed, the Taxiways and/or TaxiwayElements linked to this intersection shall also be closed up to the intersection.

  3. The application shall support the operator in avoiding cul-de-sac/dead-end situations and warn on situations when other Taxiways and/or TaxiwayElements are leading to nowhere. The application shall suggest to either include them in the NOTAM or generate a new NOTAM, as appropriate. 
  4. 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 forThe description of one or more operations, which is permitted under special conditions, usually a prior permission requirement

Taxiway/ or TaxiwayElement/ManoeuvringAreaAvailability.operationalStatus with value 'LIMITED' and 

Taxiway/ or TaxiwayElement/..Usage.type with value 'CONDITIONAL'

closed, except forTaxiway is closed, except for operations explicitly identified in the input data.

Taxiway/ or TaxiwayElement/ManoeuvringAreaAvailability.operationalStatus with value 'LIMITED' and 

Taxiway/ or TaxiwayElement/..Usage.type with value 'RESERV'

prohibited forThe description of one or more operations that are prohibited for during the event duration.

Taxiway/ or TaxiwayElement/ManoeuvringAreaAvailability.operationalStatus with value 'LIMITED' and 

Taxiway/ or 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/ or TaxiwayElement/ManoeuvringAreaAvailability.operationalStatus with value 'OTHER:EXTENDED' and 

Taxiway/ or TaxiwayElement/..Usage.type with value 'PERMIT'

operationThe specific type of operation concerned by the usage limitation update.Taxiway/ or TaxiwayElement/..Usage.operation with the following list of values CodeOperationManoeuvringAreaType

aircraft

The description of one or more aircraft (such as "helicopter") types that are exceptionally permitted on the taxiway during it's limitation.

AirportHeliport/..Availability/..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 exceptionally permitted on the taxiway during its limitation.

AirportHeliport/..Availability/..Usage/..selection/..FlightCharacteristics.

Only the following FlightCharacteristics properties are allowed to be used in this scenario: type, rule, status, military, origin, purpose.

PPR timeThe value (minutes, hours, days) of the prior permission request associated with a permitted operation.Taxiway/ or TaxiwayElement/ManoeuvringAreaAvailability/..Usage.priorPermission with uom attribute
PPR detailsAdditional information concerning the prior permission requirement.Taxiway/ or TaxiwayElement/ManoeuvringAreaAvailability/..Usage.annotation with propertyName="priorPermission" and purpose="REMARK"

reason

The reason for the taxiway usage limitation.

Taxiway/ or TaxiwayElement/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 limitation.

start time

The effective date & time when the taxiway limitation starts. This might be further detailed in a "schedule".

Taxiway/ or TaxiwayElement/TaxiwayTimeSlice/TimePeriod.beginPosition, Event/EventTimeSlice.validTime/beginPosition and Event/EventTimeSlice.featureLifetime/beginPosition

end time

The end date & time when the taxiway limitation ends.

Taxiway/ or TaxiwayElement/TaxiwayTimeSlice/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/ or TaxiwayElement/ManoeuvringAreaAvailability/Timesheet/...according to the rules for {{Schedules}}

note

A free text note that provides further details concerning the taxiway limitation.

Taxiway/ or TaxiwayElement/ManoeuvringAreaAvailability.annotation with purpose=”REMARK”

Assumptions for baseline data

It is assumed that 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:

  1. the information about the Taxiway already exists in the form of a Taxiway BASELINE TimeSlice, which contains as a minimum:
    1. a designator,
    2. a type (ex: EXIT, FASTEXT, etc), and

    3. an association with the AirportHeliport;

  2. If taxiway portions are concerned, it is assumed that they are encoded in BASELINE TaxiwayElements as suggested in the following diagram:
     
    Fig.1 - Encoding of TaxiwayElements

  3. It is assumed that each TaxiwayElements BASELINE have an annotation with purpose="OTHER:NOTAM_DESCRIPTION" and note describing their location as depicted below:
     

    Fig. 2 - Encoding of TaxiwayElement description 

    E.g. 
    * a TaxiwayElement of type INTERSECTION would have a description such as “intersection TWY A and TWY B”, 
    * a TaxiwayElement of type NORMAL would have a description such as "between RWY 08L/26R and TWY J".
  4. 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.LIM, version=2.0), for which a PERMDELTA TimeSlice may also be provided; and
  • in case of complete taxiway limitation:
    • a TEMPDELTA TimeSlice for each affected Taxiway feature, for which the "event:theEvent" property points to the Event instance created above;
  • in case of partial taxiway limitation:
    • a TEMPDELTA TimeSlice for each affected TaxiwayElement feature, for which the "event:theEvent" property points to the Event instance created above;

Identification of the TaxiwayElements to be closed shall be done as follows:

  • The application shall support the operator in order to automatically select the TaxiwayElements that are concerned with a graphical view. 
  • With reference to Fig. 1 included in the “Assumptions for baseline data” further up in the document, if the operator specifies that the portion concerned is between intersections A/B and A/D, then the application shall automatically select the portions highlighted. By default, intersections are supposed to remain open, unless explicitly specified as closed.
ER-02

First, all the BASELINE availability.ManoeuvringAreaAvailability (with operationalStatus=NORMAL), if present, shall be copied in the TEMPDELTA. 

Then, an additional availability.ManoeuvringAreaAvailability element having shall be coded in the Taxiway TEMPDELTA.

  • 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-03

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-04

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-05

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-06If 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-07

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-08

If PPR time is specified, the uom attribute shall also be specified.

ER-09If there exists a single Taxiway leading to an Apron and/or ApronElement and if the Taxiway closure makes the Apron (partially) unavailable, then a consequence APN.LIM scenario shall also be encoded for the relevant Apron feature and shall include a reference to the current event with role 'causeEvent'. 
ER-10

The system shall automatically identify the FIR where the AerodromeHeliport is located. This shall be coded as corresponding concernedAirspace property in the Event

ER-11The 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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