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[AIXM-515] Obstacle areas and assessment surfaces alignment with ICAO

[AIXM-515] Obstacle areas and assessment surfaces alignment with ICAO

Owned by POROSNICU Eduard
Last updated: 2024 Dec 10 by ADAM STYLES

ID:

AIXM-515

target version:

AIXM 5.2

version:

1.0

last updated:

08 AUG 2022

status:

APPROVED


Description

New coded values are added in the CodeObstacleAreaBaseType for the Area 2 sections (A/B/C/D) and for the different areas of Obstacle Limitation Surfaces (outer horizontal, inner approach surface, etc.) The MANAGED value is removed. The definitions of the Areas 2/3/4 are aligned with their ICAO definitions.

A new association is added from ObstacleAreaOrigin to Runway. For the association from ObstacleAreaOrigin to RunwayDirection change the name of the association, role name and description of the target class. For the association from ObstacleAreaOrigin to AirportHeliport change the description of the association.

The attribute obstructionIdSurfaceCondition of the ObstacleArea feature is deleted.

Several values that do not make sense for procedure design are removed from the CodeObstacleAssessementSurfaceBaseType.

The ObstacleAssessmentArea class is renamed ObstacleAssessmentSurface. 

Rationale for change

See https://aixmccb.atlassian.net/browse/AIXM-203 ,https://aixmccb.atlassian.net/browse/AIXM-370

The current model is missing some of the ICAO obstacles areas defined in Annex 15, 16th Edition July 2018 & ICAO Doc 10066 First Edition, 2018,  which are relevant for the Obstacle data set, viz. subtypes of Area 2 (i.e. Area 2a, Area 2b, Area 2c and Area 2d) (see also Figure A8-2 of ICAO Doc 10066 below) and the take-off flight path area (Aerodrome Obstacle Charts — ICAO Type A) defined in ICAO Annex 4,Tenth Edition, July 2001 .

Area 2 shall not be removed but kept as his own coded value used for those obstacles not covered by Area 2a-d but defined in ICAO Annex 15 in chapter 5.3.3.4.4  “For aerodromes regularly used by international civil aviation, obstacle data shall be provided for all obstacles within Area 2 that are assessed as being a hazard to air navigation.” 

ICAO Area 2a and Area 2c are related to the Runway. In the current model there is no relationship between ObstacleAreaOrigin and Runway. 

These changes make it necessary to update some descriptions/definitions of the current classes and relationships.

  




The current model contains a value OLS (ICAO Annex 14 Obstacle Limitation Surface), but is missing the “specific areas” of Obstacles Limitation Surfaces (OLS) as defined in Annex 14, Volume I, Eight Edition, July 2018,  which are relevant for the Obstacle data set (see also Figure 4-1 of ICAO Annex 14 to the right).



The attribute obstructionIdSurfaceCondition “The indicator of obstacle assessment surface that obstructing area represents (obstructionIdSurfaceCondition)” is not relevant for the ObstacleArea but only for the ObstacleAssessementArea (procedure design).

Impact assessment

[FWD_MAP_1:1] Data mapping is possible 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:

  • In the CodeObstacleAreaBaseType
    • add the following coded values:
      • AREA2A - “ICAO Area 2a: A rectangular area around a runway that comprises the runway strip plus any clearway that exists.”
      • AREA2B - “ICAO Area 2b: An area extending from the ends of Area 2a in the direction of departure, with a length of 10 km and a splay of 15 per cent to each side.”
      • AREA2C - “ICAO Area 2c: An area extending outside Area 2a and Area 2b at a distance of not more than 10 km from the boundary of Area 2a.”
      • AREA2D - “ICAO Area 2d: An area outside Areas 2a, 2b and 2c up to a distance of 45 km from the aerodrome reference point, or to an existing terminal control area (TMA) boundary, whichever is nearest.”
      • AREA2_HAZARD - “An area similar to Area 2, but which is used for identifying obstacles that have been assessed as being a hazard to air navigation and which do not match the criteria for being collected as obstacles in Area 2 A/B/C/D”
      • TAKE_OFF_FLIGHT_PATH_AREA -
      • OLS_OUTER_HORIZONTAL_SURFACE - Outer horizontal surface
      • OLS_CONICAL_SURFACE - A surface sloping upwards and outwards from the periphery of the inner horizontal surface.
      • OLS_INNER_HORIZONTAL_SURFACE - A surface located in a horizontal plane above an aerodrome and its environs.
      • OLS_APPROACH_SURFACE - An inclined plane or combination of planes preceding the threshold
      • OLS_INNER_APPROACH_SURFACE - A rectangular portion of the approach surface immediately preceding the threshold.
      • OLS_TRANSITIONAL_SURFACE - A complex surface along the side of the strip and part of the side of the approach surface, that slopes upwards and outwards to the inner horizontal surface.
      • OLS_INNER_TRANSITIONAL_SURFACE - A surface similar to the transitional surface but closer to the runway.
      • OLS_BALKED_LANDING_SURFACE - An inclined plane located at a specified distance after the threshold, extending between the inner transitional surface.
      • OLS_TAKE_OFF_CLIMB_SURFACE - An inclined plane or other specified surface beyond the end of a runway or clearway.
    • Delete the following coded value:
      • MANAGED - “A 'virtual' area containing the VerticalStructures included in the data collection exercise, which do not qualify yet as Obstacles in any specific Area”
    • Align Description of coded values with ICAO Annex 15:
      • AREA2 - “ICAO Area 2: Obstacles within Area 2 that are assessed as being a hazard to air navigation (not covered by ICAO Area 2a-d).”
      • AREA3 - “ICAO Area 3: The area bordering an aerodrome movement area that extends horizontally from the edge of a runway to 90 m from the runway centre line and 50 m from the edge of all other parts of the aerodrome movement area.” instead of “ICAO Area 3: aerodrome/heliport area.”
      • AREA4 - “ICAO Area 4: The area extending 900 m prior to the runway threshold and 60 m each side of the extended runway centre line in the direction of the approach on a precision approach runway, Category II or III.” instead of “ICAO Area 4: Category II or III operations area.”
    • Modify description of the CodeObstacleAreaBaseType:
      • “A code indicating the type of obstacle coverage area, according to ICAO Annex 15 or FAA”.

The UML class diagram to the right shows the added and deleted coded values.

  • In the ObstacleArea class:
    • delete the obstructionIdSurfaceCondition attribute
  • In the ObstacleAreaOrigin class:
  • add an association ObstacleAreaOrigin isRunway Runway
    • .* on the ObstacleAreaOrigin side,
    • .1 on the Runway side,
    • description = “Used to identify obstacles within Area 2a or Area 2c (ICAO Annex 15).”
    • role name = “ownerRunway”, description = “The Runway for which the Obstacle Area has been defined”;
  • modify the association from ObstacleAreaOrigin to RunwayDirection:
    • change the association name into isRunwayDirection
    • description = “Used to identify obstacles within a Area 4, Area 2b (ICAO Annex 15) and the Take-off Flight Path Area (ICAO Annex 4)
    • modify the role name of the RunwayDirection into “ownerRunwayDirection”, description = “The Runway Direction for which the Obstacle Area has been defined”;
  • modify the association from ObstacleAreaOrigin to AirportHeliport as follows:
    • description = “Used to identify obstacles within Area 2d or Area 3 (ICAO Annex 15)”.

The UML class diagram to the right shows the added and modified associations:

  • In the ObstacleAssessmentArea class
    • change the name of the class into ObstacleAssessmentSurface
    • change the definition into “The geometry of surfaces used to evaluate the obstructions that are taken into consideration in the design of a procedure leg, a holding pattern, etc.”
  • In the CodeObstacleAssessmentSurfaceBaseType (used for ObstacleAssessmentSurface.type attribute)
    • Add the following coded values:
      • VISUAL - “Visual area (typically 20:1 or 34:1 surfaces in TERPS, the slope is defined by the ObstacleAssessmentSurface slope element).”
      • VSS - Visual Segment Surface
      • OCS - “Obstacle Clearance Surface (the slope is defined by the ObstacleAssessmentSurface slope element).”
      • GQS - “Glidepath Qualification Surface.”
      • POFZ - “Precision Obstacle Free Zone.”
      • OIS - “Obstacle Identification Surface - Eliminated Obstacles (typically a 7:1 surface in TERPS, the slope is defined by the ObstacleAssessmentSurface slope element).”
      • PDA - “Preliminary Decision Altitude area. A level surface in the Final Approach areas of an LNAV/VNAV approach.”
      • CIRCLING - “Circling area.”
      • CIH - “Climb in Holding area.”
      • SEGMENT - “A segment area (includes primary and secondary areas) assessed to determine the minimum obstruction clearance altitude.”
      • SECTOR - “A sector surface (used for MSA/ESA, TAA areas) assessed to determine the minimum obstruction clearance altitude.”
      • SECTION_1_OCS - “The initial Obstacle Clearance Surface of a missed approach (typically ends when an aircraft would be at 400 ft AGL).”
      • SECTION_2_OCS - “The Obstacle Clearance Surface of a missed approach that follows Section 1.
      • VISUAL_20_1 - VISUAL_20_1 (20:1 = 5.00% slope) (assessment applies to all aircraft categories for straight-in approaches).”
      • VISUAL_34_1 - “VISUAL_34_1 (34:1 = 2.94% slope) (assessment applies to all aircraft categories).”
      • VISUAL_OIS - “Visual segment Obstacle Identification Surface (OIS).”
      • VISUAL_BUFFER_OIS - “Visual segment buffer Obstacle Identification Surface (OIS).”
    • Delete the following coded values:
      • AREA1 - “AREA 1”
      • AREA2 - “AREA 2”
      • AREA3 - “AREA 3”
      • ZONE1 - “AREA 1”
      • ZONE2 - “AREA 2”
      • ZONE3 - “AREA 3”

The UML class diagram to the right shows the modified class named and the updated list of values for the data type:

Mapping AIXM 5.1.1 to AIXM 5.2 (forward)

The following algorithm shall be applied:

  • [MAPC-01] For each ObstacleArea that has one of the following type values:
    • Replace “OTHER:AREA2A” with “AREA2A”
    • Replace “OTHER:AREA2B” with “AREA2B”
    • Replace “OTHER:AREA2C” with “AREA2C”
    • Replace “OTHER:AREA2D” with “AREA2D”
    • Replace “OTHER:AREA2_HAZARD” with “AREA2_HAZARD”
    • Replace “OTHER:TAKE_OFF_FLIGTH_PATH_AREA” with “TAKE_OFF_FLIGTH_PATH_AREA”
    • Replace “OTHER:OLS_OUTER_HORIZONTAL_SURFACE” with OLS_OUTER_HORIZONTAL_SURFACE
    • Replace OTHER:OLS_CONICAL_SURFACE with OLS_CONICAL_SURFACE
    • Replace OTHER:OLS_INNER_HORIZONTAL_SURFACE with OLS_INNER_HORIZONTAL_SURFACE
    • Replace OTHER:OLS_APPROACH_SURFACE with OLS_APPROACH_SURFACE
    • Replace OTHER:OLS_INNER_APPROACH_SURFACE with OLS_INNER_APPROACH_SURFACE
    • Replace OTHER:OLS_TRANSITIONAL_SURFACE with OLS_TRANSITIONAL_SURFACE
    • Replace OTHER:OLS_INNER_TRANSITIONAL_SURFACE with OLS_INNER_TRANSITIONAL_SURFACE
    • Replace OTHER:OLS_BALKED_LANDING_SURFACE with OLS_BALKED_LANDING_SURFACE
    • Replace OTHER:OLS_TAKE_OFF_CLIMB_SURFACE with OLS_TAKE_OFF_CLIMB_SURFACE
    • Replace “MANAGED” with “OTHER:MANAGED”
  • [MAPC-00] For each ObstacleArea that has a child reference_ownerRunway child element:
    • rename the element reference_ownerRunwayDirection
  • [MAPC-00] For each ObstacleAssessmentArea element
    • rename the element ObstacleAssessmentSurface
  • [MAPC-01] For each ObstacleAssessmentSurface that has one of the following type values:
    • Replace “AREA1” with “OTHER:AREA1
    • Replace “AREA2” with “OTHER:AREA2
    • Replace “AREA3” with “OTHER:AREA3
    • Replace “ZONE1” with “OTHER:ZONE1
    • Replace “ZONE2” with “OTHER:ZONE2
    • Replace “ZONE3” with “OTHER:ZONE3
    • Replace “OTHER:VISUAL” with “VISUAL”
    • Replace “OTHER:OCS” with “OCS”
    • Replace “OTHER:GQS” with “GQS”
    • Replace “OTHER:POFZ” with “POFZ”
    • Replace “OTHER:OIS” with “OIS”
    • Replace “OTHER:PDA” with “PDA”
    • Replace “OTHER:CIRCLING” with “CIRCLING”
    • Replace “OTHER:CIH” with “CIH”
    • Replace “OTHER:SEGMENT” with “SEGMENT”
    • Replace “OTHER:SECTOR” with “SECTOR”
    • Replace “OTHER:SECTION_1_OCS” with “SECTION_1_OCS”
    • Replace “OTHER:SECTION_2_OCS” with “SECTION_2_OCS”
    • Replace “OTHER:VISUAL_20_1” with “VISUAL_20_1”
    • Replace ”OTHER:VISUAL_34_1” with “VISUAL_34_1”
    • Replace “OTHER:VISUAL_OIS” with “VISUAL_OIS”
    • Replace “OTHER:VISUAL_BUFFER_OIS” with “VISUAL_BUFFER_OIS”
  • [MAPC-99] For each ObstacleArea that has a child ObstructionIdSurfaceComposition element, no mapping is considered necessary..

Mapping AIXM 5.2 to AIXM 5.1.1 (backward)

The following algorithm shall be applied:

  • [MAPC-01] For each ObstacleArea that has one of the following type values:
    • Replace “AREA2A” with “OTHER:AREA2A”
    • Replace “AREA2B” with “OTHER:AREA2B”
    • Replace “AREA2C” with “OTHER:AREA2C”
    • Replace “AREA2D” with “OTHER:AREA2D”
    • Replace “AREA2_HAZARD” with “OTHER:AREA2_HAZARD”
    • Replace “TAKE_OFF_FLIGTH_PATH_AREA” with “OTHER: TAKE_OFF_FLIGTH_PATH_AREA”
    • Replace “OLS_OUTER_HORIZONTAL_SURFACE” with OTHER:OLS_OUTER_HORIZONTAL_SURFACE
    • Replace OLS_CONICAL_SURFACE with OTHER:OLS_CONICAL_SURFACE
    • Replace OLS_INNER_HORIZONTAL_SURFACE with OTHER:OLS_INNER_HORIZONTAL_SURFACE
    • Replace OLS_APPROACH_SURFACE with OTHER:OLS_APPROACH_SURFACE
    • Replace OLS_INNER_APPROACH_SURFACE with OTHER: OLS_INNER_APPROACH_SURFACE
    • Replace OLS_TRANSITIONAL_SURFACE with OTHER:OLS_TRANSITIONAL_SURFACE
    • Replace OLS_INNER_TRANSITIONAL_SURFACE with OTHER:OLS_INNER_TRANSITIONAL_SURFACE
    • Replace OLS_BALKED_LANDING_SURFACE with OTHER:OLS_BALKED_LANDING_SURFACE
    • Replace OLS_TAKE_OFF_CLIMB_SURFACE with OTHER:OLS_TAKE_OFF_CLIMB_SURFACE


  • [MAPC-00] For each ObstacleArea that has a child reference_ownerRunwayDirection child element:
    • rename the element reference_ownerRunway
  • [MAPC-02] For each ObstacleArea that has a reference_ownerRunway element:

From the three backward mapping options discussed for this case, the first two (discard the value or use an extension) are straightforward and do not need any further details. The 3rd 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:

    • Add an annotation.Note associated to ObstacleArea
      • purpose=“OTHER:BACKWARD_MAPPING”;
      • propertyName = “reference_ownerRunway”;
      • LinguisticNote.note=”isRunway Runway identified by xlink:href=... (copy the value of the ownerRunway@xlink:href...”)
    • In addition, if there exist at least one RunwayDirection associated with the Runway targeted by the xlink:href value, then:
      • add a child reference_ownerRunway with the xlink:href value equal-to the gml:identifier of the corresponding RunwayDirection
    • delete the reference_ownerRunway element
  • [MAPC-00] For each ObstacleAssessmentSurface element
    • rename the element ObstacleAssessmentArea
  • [MAPC-01] For each ObstacleAssessmentArea has one of the following type values:
    • Replace “VISUAL” with OTHER:VISUAL
    • Replace “OCS” with OTHER:OCS
    • Replace “GQS” with OTHER:GQS
    • Replace “POFZ” with OTHER:POFZ
    • Replace “OIS” with OTHER:OIS
    • Replace “PDA” with OTHER:PDA
    • Replace “CIRCLING” with OTHER:CIRCLING
    • Replace “CIH” with OTHER:CIH
    • Replace “SEGMENT” with OTHER:SEGMENT
    • Replace “SECTOR” with OTHER:SECTOR
    • Replace “SECTION_1_OCS” with OTHER:SECTION_1_OCS
    • Replace “SECTION_2_OCS” with OTHER:SECTION_2_OCS
    • Replace “VISUAL_20_1” with OTHER:VISUAL_20_1
    • Replace ”VISUAL_34_1” with OTHER:VISUAL_34_1
    • Replace “VISUAL_OIS” with OTHER:VISUAL_OIS
    • Replace “VISUAL_BUFFER_OIS” with OTHER:VISUAL_BUFFER_OIS

Mapping example

(Note: for mapping test data see: https://github.com/aixm/mapping_52_511/tree/master/AIXM-515) 

InputOutput