Information Manual. Lighting requirements for air traffic control purposes can be found
in Air Traffic Control, FAA Order 7110.65.
Miscellaneous Airport Lighting
There are a number of other lighting systems that you should be aware of as an air
traffic controller. Your facility may have some, all, or none of these systems. Whatever
the case, you should become completely familiar with the systems at your facility.
Visual Approach Slope Indicator
The Visual Approach Slope Indicator (VASI) is designed to provide visual descent
guidance information during the approach to a runway. The two-bar VASI system
provides one visual glide path normally set at 3 degrees. A three-bar system provides
two visual glide paths. The lower glide path is normally set at three degrees, and the
higher glide path is normally set ¼ of a degree higher. Local obstruction may cause a
facility to have a different glide path angle than listed here. The VASI system consists of
red and white lights located beside the runway that provide the pilot with the glide slope
information as seen in Table 4-3.
Above the glide slope
White over white
On the glide slope
Red over white
Below the glide slope
Red over red
Table 4-3 -- Visual approach slope indicator
The light units are arranged so that the pilot, during an approach, would see one of the