Document ID: chunk:federal_register_of_legislation:F2024C01244:reg:5:p130
Version: federal_register_of_legislation:F2024C01244
Segment Type: reg
Provision Reference: reg 5 (pt 130/225)
Character Range: 647548–650313

beam is calculated by:

(a) establishing grid points as shown in Figure 9.111 (7); and

(b) using the intensity values measured at all grid points located within and on the perimeter of the rectangle representing the main beam; and

(c) calculating the arithmetic average of the light intensity values measured at those grid points.

       (4) No deviations in candela values are permitted in the main beam when the lighting fixture is properly aimed.

       (5) Horizontal angles must be measured with respect to the vertical plane through the taxiway centreline, except on curves which must be measured with respect to the tangent to the curve.

       (6) Vertical angles must be measured from the longitudinal slope of the taxiway surface.

       (7) The light unit must be installed so that the main beam is aligned within 0.5 degrees of the specified requirement.

       (8) On the perimeter of, and within the rectangle defining the main beam, the maximum light intensity value must not to be greater than 3 times the minimum light intensity measured in the same way.

       (9) The following apply to the Figures:

(a) for Figure 9.111 (1) — if omnidirectional lights are used they must comply with the vertical beam spread;

(b) for Figures 9.111 (2) and 9.111 (5) — lights on curves must have the light beam toed-in 15.75º with respect to the tangent of the curve.
     Figure 9.111 (1)   Isocandela diagram for taxiway centreline lights, no entry bar lights and stop bar lights on straight sections of taxiways intended for use in RVR conditions of 350 m or greater (shows matters)

Notes
       1. The intensity values have taken into account high background luminance, and the possibility of deterioration of light output resulting from dust and local contamination.
       2. If omnidirectional lights are used they must comply with the vertical beam spread.

     Figure 9.111 (2)   Isocandela diagram for taxiway centreline lights, no entry bar lights and stop bar lights on curved sections of taxiways intended for use in RVR conditions of 350 m or greater (shows matters)

Notes
1. The intensity values have taken into account high background luminance, and the possibility of deterioration of light output resulting from dust and local contamination.
2. Lights on curves must have the light beam toed-in 15.75º with respect to the tangent to the curve.
3. These beam coverages allow for displacement of the cockpit from the centreline up to a distance of 12 m as could occur at the end of curves.

     Figure 9.111 (3)   Isocandela diagram for taxiway centreline lights, no entry bar lights and stop bar lights on taxiways intended for use in RVR conditions less than 350 m — for use on straight sections of taxiways where large offsets