Page 339 - Planning and Design of Airports

Airport Lighting, Marking, and Signage 297

3000'
500'
100'

RUNWAY THRESHOLD CENTRE LINE LIGHTS HORIZON BAR LIGHTS
FIGURE 8-3 Calvert approach lighting system.

For operations in very poor visibility, ICAO has certified a modifi-
cation of the Calvert system, known as the ICAO category II system.
The variation calls for a higher lighting intensity to the inner 300 m
of the system closest to the runway threshold. The category II and
category III system adopted by ICAO shown in Fig. 8-4 consists of two
lines of red bars on each side of the runway centerline and a single line
of white bars on the runway centerline both at 30 m intervals and both
extending out 300 m from the runway threshold. In addition, there are
two longer bars of white light at a distance of 150 and 300 m from the
runway threshold, and a long threshold bar of green light at the run-
way threshold. ICAO also recommends that the longer bars of white
light also be placed at distances of 450, 500, and 750 m from the run-
way threshold if the runway centerline lights extend out that distance
as shown in Fig. 8-4.
The ALSs currently certified by the FAA for installation in the
United States consist of a high-intensity ALS with sequenced flashing
lights (ALSF-2), which is required for category II and category III
precision approaches, a high-intensity approach lighting system with

300 m 600 m

150 m 150 m 150 m 150 m

ICAO
CAT II–III

Red Lights
White Lights
Green Lights
FIGURE 8-4 ICAO CAT II-III approach lighting system.