Document ID: chunk:federal_register_of_legislation:F2024C01244:reg:5:p91
Version: federal_register_of_legislation:F2024C01244
Segment Type: reg
Provision Reference: reg 5 (pt 91/225)
Character Range: 548515–551144

the following standards as illustrated in Figure 9.45 (1):

 (i) the baseline must be 150 m wide and coincident with the existing baseline for the approach surface;

 (ii) the slope must be 1.9º;

 (iii) the splay must be 7.5º outwards, commencing from the ends of the baseline;

 (iv) the length must be 9 km measured from the baseline.

     Figure 9.45 (1)   Obstacle assessment surface for 3° approach slope (illustrates matters)

       (2) If an object or structure, for example a radio mast, a building or high terrain, infringes the OAS, the aerodrome operator must apply to CASA for a written determination as to whether the object or structure would adversely affect the safety of aircraft operations.

       (3) Unless CASA determines that the object or structure would not adversely affect the safety of aircraft operations, the operator must take all reasonable steps to:

(a) remove the object or structure; or

(b) have the entity responsible for the object or structure remove it.

       (4) If it is not possible to remove the object or structure, then the aerodrome operator must:

(a) raise the approach slope of the VASIS:

 (i) for a runway used by jet engine aeroplanes — to a maximum of 3.3°, and also raise the OAS slope by the same amount; or

 (ii) for a runway used by other aeroplanes — to a maximum of 3.5°, and also raise the OAS slope by the same amount; or

(b) reduce the azimuth spread so that the object or structure is outside the confines of the T-VASIS or PAPI beam; or

(c) displace the axis of the VASIS and its associated OAS by up to 5°; or

(d) displace the threshold; or

(e) if action under paragraph (d) is not possible, displace the VASIS upwind of the threshold to provide an increase in threshold crossing height equal to the height of the obstacle penetration.

9.46 T-VASIS and AT-VASIS

Note   A T-VASIS is a set of lights so arranged that the pattern seen by the pilot varies according to his or her position (up or down, left or right) relative to the desired approach path. When installed in the runway strip, a T‑VASIS provides pilots with visual cues indicating their actual descent path relative to the desired descent path.

     Figure 9.46 (1)   T-VASIS layout (shows matters)

       (1) A T-VASIS must consist of 20 light units symmetrically disposed about a runway centreline as shown in Figure 9.46 (1), and comprising:

(a) 2 rows (wing bars) of 4 light units each; and

(b) 2 longitudinal lines of 6 lights each, bisecting each of the wing bars.

       (2) An AT-VASIS must consist of 10 light units arranged on one side of a runway and comprising:

(a) a