Document ID: chunk:federal_register_of_legislation:F2024C01244:reg:5:p203
Version: federal_register_of_legislation:F2024C01244
Segment Type: reg
Provision Reference: reg 5 (pt 203/225)
Character Range: 842571–845323

surface type.

       (7) The buffer zone around an instrument enclosure must:

(a) be covered by the natural vegetation or ground cover of the region; and

(b) have the vegetation or ground cover maintained to a height of approximately 0.5 m.

       (8) Any isolated obstruction under 15 m in height (for example, a mast, a post or a tree) must be at least 4 times the height of the obstruction distant from any point in the instrument enclosure.

       (9) Subsection (7) also applies to the aerodrome weather station electronics unit, if installed.

       (10) Subject to subsection (8), any obstruction that:

(a) is 15 m or more in height, or that is in the form of a shed or a similar built structure; and

(b) covers more than 45° of azimuth;

        must be at least 10 times the height of the obstruction distant from any point in the instrument enclosure.

       (11) Subsection (8) does not apply to an isolated mast which:

(a) is of a diameter or width so small that it does not obstruct direct solar radiation from falling on the instrument enclosure; and

(b) lies down-wind of the prevailing winds to mitigate the risk of producing rain shadows.

CHAPTER 20 EARTHING POINTS

20.01 Ground earthing points

       (1) An aerodrome operator may provide ground earthing points at an aerodrome, and if provided, the resistance to earth must not exceed 10 000 ohms.

Note   If a ground earthing point is provided, CASA recommends that it should only be provided in consultation with the aerodrome fuelling agent.

       (2) Each ground earthing point on the apron must be tested for its electrical resistance:

(a) as part of the initial installation; and

(b) when it is being replaced; and

(c) 6 months after the installation; and

(d) 6 months after any replacement; and

(e) otherwise as part of the aerodrome technical inspection.

       (3) Without affecting subsection (2), each ground earthing point on the apron must be visually inspected not later than every 3 months after the commencement of this MOS, to ensure that:

(a) the ground earthing point is:

 (i) firmly connected to the earthing rod; and

 (ii) seated on the pavement; and

(b) the earthing rod is firmly embedded in the ground; and

(c) the fins used for making electrical connections are free from dirt, grease, paint, or any other contaminating substance; and

(d) no ground earthing points have been buried or removed.

Note   Visual inspections under subsection (3) are additional to the tests otherwise required for electrical resistance under subsection (2).

       (4) If testing shows that the ground earthing points are sound, they must be marked with a 15 cm diameter circle, coloured white.

       (5) If :

(a) the resistance to earth exceeds