[AIXM-586] Support for Pavement Classification Rating (PCR)

Description

Additional attributes are added in the SurfaceCharacteristics class specifically for the PCR surface strength publication method. The PCN-specific data types are renamed and their lists of allowable values are redefined in order to be applicable for both the PCR and PCN methods.

Rationale for change

See https://aixmccb.atlassian.net/browse/AIXM-486

ICAO has approved the replacement of the ACN/PCN with the new ACR/PCR method, which will be applicable from November 2024. The SurfaceCharacteristics class needs to be updated in order to support the new PCR values.

During the transition period it is possible that some States will provide both PCR and PCN values for the same surface. This would be a similar situation to the current provision of both PCN and LCN values for the same surface by some States. Therefore, it is proposed that additional attributes are added in the SurfaceCharacteristics class specifically for the PCR method.

The PCR values to be provided in AIS products have a similar structure to the current PCN values. Therefore, the data types and codelists used for PCN attributes may be reused for the new PCR attributes once the PCN specific nomenclature is removed. The maximum length of the ValPCNBaseType needs to be extended to 4 digits, as the PCR values are numerically higher by one level of magnitude than the previous PCN values.

Impact assessment

[FWD_1:1] No data mapping is necessary and no data loss occurs when data is exchanged from a system (A) that uses AIXM 5.1.1 for output towards a system (B) that uses AIXM 5.2 for input.

[BWD_MAP_LOSS] Data mapping is possible, but some data would be lost (or converted into Notes) when data is exchanged from a system (B) that uses AIXM 5.2 for output towards a system (A) that uses AIXM 5.1.1 for input.

Change Proposal details

In the UML model

• Rename the class ValPCNBaseType into ValPavementStrengthBaseType, change its definition into “The value of a pavement bearing strength, according to the strength method or standard” and
  • change the pattern to allow one more digit for the integer part: [0-9]{1,4}(\.[0-9]){0,1}
• Rename the class ValPCNType into ValPavementStrengthType
• Rename the class CodePCNPavementBaseType into CodePavementBehaviourBaseType and change its definition into “A code indicating the pavement behaviour (rigid or flexible) used for determining the pavement strength according to the method or standard applied” and
• Rename the class CodePCNPavementType into CodePavementBehaviourType
• Rename the class CodePCNSubgradeBaseType into CodePavementSubgradeBaseType and change its definition into “A code indicating the pavement subgrade strength category according to the method or standard applied”
• Rename the class CodePCNSubgradeType into CodePavementSubgradeType
• Rename the class CodePCNTyrePressureBaseType into CodeTyrePressureBaseType and change its definition into “A code indicating the maximum allowable tyre pressure category related to a the pavement strength method or standard applied” and modify the definitions of its codelist as follows:
  • W = Unlimited;
  • X = High (according to the method used);
  • Y = Medium (according to the method used);
  • Z = Low (according to the method used);
  • OTHER = Other
• Rename the class CodePCNTyrePressureType into CodeTyrePressureType
• Rename the class CodePCNMethodBaseType into CodePavementStrengthMethodBaseType and change its definition into “A code indicating the method used in the evaluation of the pavement strength according to the standard applied”
• Rename the class CodePCNMethodType into CodePavementStrengthMethodType
• In the SurfaceCharacteristics class:
  • add a new attribute classPCR, data type ValPavementStrengthType, definition: “The bearing strength of a pavement for unrestricted operations, according to the Pavement Classification Rating (PCR).”
  • add a new attribute pavementTypePCR, data type CodePavementBehaviourType, definition: “The pavement behaviour (rigid or flexible) used for determining the pavement strength according to the Pavement Classification Rating (PCR).”
  • add a new attribute pavementSubgradePCR, data type CodePavementSubgradeType, definition definition to “An indication of the pavement subgrade strength according to the Pavement Classification Rating (PCR).”
  • add a new attribute maxTyrePressurePCR, data type CodeTyrePressureType, definition: “The maximum allowable tire pressure category related to the Pavement Classification Rating (PCR).”
  • add a new attribute evaluationMethodPCR, data type CodePavementStrengthMethodType, definition: “The method used to rate a runway pavement related to the Pavement Classification Rating (PCR).”

The following UML class diagram indicates the new/changed elements:

Mapping AIXM 5.1.1 to AIXM 5.2 (forward)

• Not applicable

Mapping AIXM 5.2 to AIXM 5.1.1 (backward)

[MAPC-02] For each SurfaceCharacteristics that has specified classPCR, pavementTypePCR, pavementSubgradePCR, maxTypePressurePCR or evaluationMethodPCR child elements:

From the three backward mapping options applicable in this case, the first two (discard the value or use an extension) are straightforward and do not need any further details. The 3^rd option (backward mapping into a Note) is detailed in order to provide a complete description of this case and its conversion option. The following mapping into Note algorithm is proposed:

• Remove the classPCR, pavementTypePCR, pavementSubgradePCR, maxTypePressurePCR and/or evaluationMethodPCR as applicable;
• Add an annotation.Note associated with the SurfaceChacateristics object having:
• purpose=“OTHER:BACKWARD_MAPPING”
• LinguisticNote.note=”classPCR: <value of classPCR>, pavementTypePCR: <value of pavementTypePCR>, pavementSubgradePCR: <value of pavementSubgradePCR>, maxTypePressurePCR: <value of maxTypePressurePCR>, evaluationMethodPCR: <value of evaluationMethodPCR> ”.

Mapping example

(Note: for mapping test data see: https://github.com/aixm/mapping_52_511/tree/master/AIXM-xxx) 

AIXM Input	AIXM Output