Have you ever wondered how pilots are able to determine the location of an airport at night or in reduced visibility? Well the answer is actually very simple. At night, the location of an airport can be determined by the presence of an airport rotating beacon light like the one seen in the image below. An airport beacon will assist you as a pilot in identifying the location and type of airport by the color combination the beacon is emitting.
The colors and color combinations that denote the type of airports are:
*Note: Green alone or amber alone is used only in connection with a white-and-green or white-and-amber beacon display, respectively.
A civil-lighted land airport beacon will show alternating white and green flashes. A military airfield will be identified by dual-peaked (two quick) white flashes between green flashes.
In Class B, C, D, or E airspace, operation of the airport beacon during the hours of daylight often indicates the ceiling is less than 1,000 feet and/or the visibility is less than 3 miles. However, pilots should not rely solely on the operation of the airport beacon to indicate if weather conditions are IFR or VFR.
The beacon has a vertical light distribution to make it most effective from 1–10° above the horizon, although it can be seen well above or below this spread.
Here is another nifty little tidbit you will learn once you start night flight training. Radio control of lighting is available at some airports, providing airborne control of lights by keying the aircraft’s microphone. The control system is responsive to 7, 5, or 3 microphone clicks. Keying the microphone 7 times within 5 seconds will turn the lighting to its highest intensity; 5 times in 5 seconds will set the lights to medium intensity; low intensity is set by keying 3 times in 5 seconds. Many airports, particularly airports without an operating control tower, will not keep runway lights on constantly throughout the night so it becomes the pilots responsibility to turn the runway lights on for landing or takeoff. Once the lights are keyed on they will typically remain on for 15 minutes. A quick glance in the Chart Supplement U.S. will identify an airport with pilot controlled lighting.