b) Obstacle Area

Summary of requirements

The various areas for which obstacle data has to be collected and provided are not defined as aeronautical data subjects and properties in the PANS-AIM. Instead, they are defined implicitly through provisions contained in the Annex 15 and/or the PANS-AIM document. For mapping purposes, the provisions contained in the ICAO documents are used to identify the properties of the obstacle areas.

Annex 15 contains the following provisions related to the geometry and location of the obstacle areas:

5.3.3.4.3 "The obstacle data shall be provided for obstacles in Area 1 whose height is 100 m or higher above ground".

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."

5.3.3.4.5 "For aerodromes regularly used by international civil aviation, obstacle data shall be provided for:

a)    Area 2a for those obstacles that penetrate an obstacle data collection surface outlined by a rectangular area around a runway that comprises the runway strip plus any clearway that exists. The Area 2a obstacle collection surface shall have height of 3 m above the nearest runway elevation measured along the runway centre line, and for those portions related to a clearway, if one exists, at the elevation of the nearest runway end;
b)    objects in the take-off flight path area which project above a plane surface having a 1.2 per cent slope and having a common origin with the take-off flight path area; and
c)    penetrations of the aerodrome obstacle limitation surfaces.

Note.— Take-off flight path areas are specified in Annex 4, 3.8.2. Aerodrome obstacle limitation surfaces are specified in Annex 14, Volume 1, Chapter 4."

5.3.3.4.6 Recommendation.—  For aerodromes regularly used by international civil aviation, obstacle data should be provided for Areas 2b, 2c and 2d for obstacles that penetrate the relevant obstacle data collection surface specified as follows:

a)    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% to each side. The Area 2b obstacle collection surface has a 1.2% slope extending from the ends of Area 2a at the elevation of the runway end in the direction of departure, with a length of 10 km and a splay of 15% to each side;
b)    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. The Area 2c obstacle collection surface has a 1.2% slope extending outside Area 2a and Area 2b at a distance of not more than 10 km from the boundary of Area 2a. The initial elevation of Area 2c shall be the elevation of the point of Area 2a at which it commences; and
c)    Area 2d: an area outside the Areas 2a, 2b and 2c up to a distance of 45 km from the aerodrome reference point, or to an existing TMA boundary, whichever is nearest. The Area 2d obstacle collection surface has a height of 100 m above ground;

except that data need not be collected for obstacles less than a height of 3 m above ground in Area 2b and less than a height of 15 m above ground in Area 2c.

5.3.3.4.7 Recommendation.— Arrangements should be made for the coordination of providing obstacle data for adjacent aerodromes where their respective coverage areas overlap to assure that the data for the same obstacle are correct.
5.3.3.4.8 Recommendation.— For those aerodromes located near territorial boundaries, arrangements should be made among States concerned to share obstacle data.
5.3.3.4.9 Recommendation.—  For aerodromes regularly used by international civil aviation, obstacle data should be provided for Area 3 for obstacles that penetrate the relevant obstacle data collection surface extending a half-metre (0.5 m) above the horizontal plane passing through the nearest point on the aerodrome movement area.
5.3.3.4.10 For aerodromes  regularly used by international civil aviation, obstacle data shall be provided  for  Area  4 for all runways where precision approach Category II or III operations have been established.
5.3.3.4.11 Recommendation.— Where additional obstacle data are collected to meet other aeronautical requirements, the obstacle data sets should be expanded to include these additional data.

PANS-AIM further details some of these provisions, including a depiction of the various areas in Appendix 8:

5.3.3.2.2.4 The obstacle data product specification, supported by geographical coordinates for each aerodrome included within the dataset, shall describe the following areas:

— Areas 2a, 2b, 2c, 2d;

— the take-off flight path area; and

— the obstacle limitation surfaces.

Mapping to AIXM

The obstacle area properties as identified previously map to AIXM 5.1(.1) elements that appear in the following diagram.