Document ID: chunk:federal_register_of_legislation:F2024C01244:reg:5:p95
Version: federal_register_of_legislation:F2024C01244
Segment Type: reg
Provision Reference: reg 5 (pt 95/225)
Character Range: 557773–561033

tolerances for design etc.

Item                                                            Standard                       Allowable tolerance
Eye height over threshold                                       15 m1,2                        +1 m  –3 m
Approach slope3                                                 3° (1:19 nominal)
Distance of longitudinal line of light units from runway edge4  30 m                           ±3 m
Leg light unit spacing                                          45 m                           ±4.5 m
                                                                90 m                           ±9 m
Clearance from pavements                                        15 m5
Alignment of each light unit                                    Parallel to runway centreline  ±1°
Light units in a wing bar
   Fronts of light units                                        Aligned                        ±25 mm
   Height of light units                                        Aligned                        ±25 mm
Levelling of light units                                        Level                          To the accuracy of the precision engineer's level.6

       (6) For Table 9.47 (5), an item, standard or allowable tolerance with a number attached in superscript is subject to or informed by (as the case requires) the content of whichever of the following items has the same number:

1. When the runway on which a T-VASIS is provided is equipped with an ILS, the siting and elevations of the T-VASIS must be such that the visual approach slope conforms as closely as possible to the glide path of the ILS.

2. A T-VASIS eye height over threshold 1 m higher than the ILS glide path satisfies most, but not all, aircraft.

3. The use of a different approach slope is permitted, but only with the prior written approval of CASA.

4. The edge of the runway is defined as the perpendicular distance from the runway centreline, which is half the nominal width of the runway and ignores sealed shoulders.

5. There is a minimum clearance between any part of a T-VASIS light unit (but not the foundation slab) and an adjacent runway or taxiway pavement.

6. This includes end-for-ending the level to ensure no inaccuracy of the instrument.

       (7) The aerodrome operator must ensure that the immediate surround of each light unit is kept free of grass.

Note   Tall grass immediately in front of the light unit could provide conflicting light signals. Grass growing near the box on any side could result in the fine settings being disturbed during power mowing operations.

9.48 Precision approach path indicator system (PAPI)

       (1) The precision approach path indicator system (a PAPI) must consist of a row (a wing bar) of 4 equally-spaced sharp transition multi-lamp units or paired single-lamp units.

       (2) Subject to subsection (3), the system must be located on the left-hand side of a runway, as viewed by the pilot of an aircraft approaching to land on the runway.

       (3) If an existing taxiway or physical obstruction makes it impossible to locate the units on the left-hand side of the runway, the PAPI can be placed on the right-hand side of the runway.

       (4) As shown in Figure 9.50 (5), a PAPI must