The floodlighting system may be provided with automatic control means, as a photocell or astronomic time switch to prevent consumption of energy during the daytime. The photocell is set so that is ON setting corresponds to about 300 lux of northsky light intensity and its OFF setting to about 600 lux of northsky light intensity.
A by-pass switch should be provided where automatic control is used, so that the lights may be turned ON during the daytime for maintenance purposes.
A time switch may also be provided to turn the floodlights OFF, at airports where operations cease after a certain hour during the night.
Where automatic control of floodlighting is installed, it is not recommended that a by-pass means be provided for use by the Air Traffic Controller for the reasons below.