Class III precision approach airport lighting system consists of the center line lamp, horizontal row of lights and side lights, these three kinds of lights are row lights. The center line lights must consist of a line extending along the runway midline and as far as 900 m from the runway entrance.
The centerline lamps must have a longitudinal spacing of 30m and the innermost lamps should be located 30m from the entrance to the runway. In addition, the system must also have two rows of sidelights extending to 270m from the entrance to the runway and two rows of horizontal lights, one row at 150m from the entrance and the other row at 300m from the entrance.
Class III precision approach airfield lighting system near the first runway entrance 300m part of the center line light must be made of variable white light short bar lights. When the runway entrance 300m or more within the shift, this part of the center line lamp can be made by the variable white light single composition. The length of the bar must be at least 4 m. When the bar is composed of approximately a point light, the luminaires must be evenly spaced at a distance of not more than 1.5 m. The center line lights 300m away from the entrance of the runway are the same as the first 300m or the double lamp light source 300m in the middle of the middle line and the three-lamp light source 300m in the outer end of the center line. Above lamps must be made variable white light.
If the center line lights 300m away from the entrance of the runway are short bar lamps, a short circuit lamp of 300m each must be provided with a capacitor discharge lamp (unless it is not considered necessary after considering the nature of the airport and runway lighting systems lighting system and the nature of the weather conditions) plus). Each capacitor discharge lamp must flash twice per second, flashing from the outermost lamp to the entrance, one after the other, up to the very first lamp in the system. The circuit design must allow the discharge lamp to be operated separately from the other lamps in the approach lighting system.
Side lamps of lamps must be located in the middle of the good policy, the longitudinal spacing and longitudinal centerline lamp spacing equal. The first bar light is located 30m away from the entrance. The lateral spacing between the fixtures closest to the midline between two rows of sidelights must be between 15 m and 22.5 m, preferably 18 m. But in any case it must be the same as the horizontal spacing of the grounded zone lamps