13.5.20 The perimeter of the TLOF should be delineated
by green lights visible omnidirectionally from on or above the landing
area. These lights should be above the level of the deck but should
not exceed 0.25 m in height for helidecks sized in accordance with
paragraph 13.3.2 and 0.05 m in height for helidecks sized in accordance
with paragraph 13.3.3. The lights should be equally spaced at intervals
of not more than 3 m around the perimeter of the TLOF, coincident
with the white line delineating the perimeter in paragraph 13.5.10.
In the case of square or rectangular decks there should be a minimum
of four lights along each side including a light at each corner of
the TLOF. Flush fitting lights may be used at the inboard (150°
limited obstacle sector origin) edge of the TLOF where there is a
need to move a helicopter or large equipment off the TLOF.
13.5.21 Perimeter lights should meet the chromaticity
characteristics given in table 13-1,
and the vertical beam spread and intensity characteristics given in table 13-2.
Table 13-1 Perimeter lighting
chromaticity
| Yellow boundary
|
x = 0.36 –
0.08y
|
| White boundary
|
x = 0.65y
|
| Blue boundary
|
y = 0.9 –
0.171x
|
Table 13-2 Green perimeter
lighting intensity
|
Elevation
|
Intensity (cd)
|
| 0° − 90°
|
60 max*
|
| >20° − 90°
|
3 min
|
| >10° − 20°
|
15 min
|
| 0° − 10°
|
30 min
|
| Azimuth +180° -180°
|
| *
|
If higher intensity lighting is provided to assist in
conditions of poor visibility during daylight, it should incorporate a
control to reduce the intensity to not more than 60 cd for night
use.
|