Page 334 - Planning and Design of Airports

292 Airp o r t D e sign

Airfield lighting, marking, and signage facilities provide the following
functions:

1. Ground to air visual information required during landing
2. The visual requirements for takeoff and landing
3. The visual guidance for taxiing
In the United States, the Federal Aviation Administration provides
guidance for designing standard airfield lighting, marking, and sig-
nage, through published Advisory Circulars. These Advisory Circu-
lars are frequently updated. The standards described in this text are
current as of 2007. Current advisory circulars may be found at the
FAA’s website at http://www.faa.gov.

The Requirements for Visual Aids
Since the earliest days of flying, pilots have used ground references for
navigation when approaching an airport, just as officers on ships at
sea have used landmarks on shore when approaching a harbor. Pilots
need visual aids in good weather as well as in bad weather and during
the day as well as at night.
In the daytime there is adequate light from the sun, so artificial
lighting is not usually required but it is necessary to have adequate
contrast in the field of view and to have a suitable pattern of bright-
ness so that the important features of the airport can be identified and
oriented with respect to the position of the aircraft in space. These
requirements are almost automatically met during the day when the
weather is clear.
The runway for conventional aircraft always appears as a long nar-
row strip with straight sides and is free of obstacles. It can therefore be
easily identified from a distance or by flying over the field. Therefore,
the perspective view of the runway and other identifying reference
landmarks are used by pilots as visual aids for orientation when they
are approaching the airport to land. Experience has demonstrated that
the horizon, the runway edges, the runway threshold, and the center-
line of the runway are the most important elements for pilots to see.
In order to enhance the visual information during the day, the run-
way is painted with standard marking patterns. The key elements in
these patterns are the threshold, the centerline, the edges, plus multi-
ple parallel lines to increase the perspective and to define the plane of
the surface.
During the day when visibility is poor and at night, the visual
information is reduced by a significant amount over the clear weather
daytime scene. It is therefore essential to provide visual aids which
will be as meaningful to pilots as possible.