LIGHTING CIRCUITS

Several different lighting circuits are used on airfields: runway edge lighting circuits, taxiway lighting circuits, approach lighting circuits, obstruction lighting circuits, beacon lighting circuits, and the condenser discharge circuits, which will be covered separately.

Figure 2-4.\Typical remote control panel operating controls.

Runway Edge Lights give off is aviation white (clear). The edge lights are installed not more than 10 feet from the edge

Runway edge lighting is designed to show the of the full-strength runway paving. Both lines of width and length of the usable landing area; there lights will be the same distance from the runway are two rows of lights, one row on each side, that center line. It is best if the lines of lights are run the length of the runway. The light they located as close to the runway as the base

Figure 2-5.\Airfield lighting control system.

mounting for the lights allows. The lights are equally spaced along the runway at distances not to exceed 200 feet. (See fig. 2-6.)

The runway lighting controls are set up so that the lights on intersecting runways cannot be on at the same time. Also, the controls must turn all the light systems of one runway on at the same time. The runway edge lights are controlled so all the lights are the same brightness. In a highintensity system, threshold lights are one step higher than the runway edge lights, except when the runway edge lights are at full brightness. At this time, the runway edge lights and the threshold lights are at full brightness. In a medium-intensity runway lighting system, all lights (runway edge lights and threshold lights) are the same brightness.

In some instances, it is a good practice to use runway edge light fixtures and lamps for the threshold lights, so that the difference is noticeable when the threshold lighting configuration has to be stepped up one brightness higher than the runway edge lights. To determine the number of circuits required for runway edge lights, you need to determine the length of the runway. You determine the number of lights on one circuit by considering not only the number of lights connected to the circuit but also the volt/ampere loss for the circuit cables and the feeder cables from the vault to the runway. If this distance is long, you may need to adjust the number of lights in the circuit.

Do not load the regulator less than one-half of its rated kW output. If more than one regulator is required, each regulator should be equally loaded.

Each light circuit will be fed by a series loop.

The current leaves one terminal of the CCR, goes through the circuit to each light unit, and returns to the other terminal of the regulator.

Taxiway Lights

Taxiway lights are used to show the pilot the width and direction of the "taxiing route." The lights are aviation blue in color. They are basically the same as runway lighting circuits.