Aerodrome beacon
Encyclopedia
An aerodrome beacon or rotating beacon is a beacon
Beacon
A beacon is an intentionally conspicuous device designed to attract attention to a specific location.Beacons can also be combined with semaphoric or other indicators to provide important information, such as the status of an airport, by the colour and rotational pattern of its airport beacon, or of...

 installed at an airport
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...

 or aerodrome
Aerodrome
An aerodrome, airdrome or airfield is a term for any location from which aircraft flight operations take place, regardless of whether they involve cargo, passengers or neither...

 to indicate its location to aircraft pilots at night.
An aerodrome beacon is mounted on top of a towering structure, often a control tower
Control tower
A control tower, or more specifically an Air Traffic Control Tower , is the name of the airport building from which the air traffic control unit controls the movement of aircraft on and around the airport. Control towers are also used to control the traffic for other forms of transportation such...

, above other buildings of the airport. It produces flashes not unlike that of a lighthouse
Lighthouse
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....

.

Airport
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...

 and heliport
Heliport
A heliport is a small airport suitable only for use by helicopters. Heliports typically contain one or more helipads and may have limited facilities such as fuel, lighting, a windsock, or even hangars...

 beacons are designed in such a way to make them most effective from one to ten degrees above the horizon; however, they can be seen well above and below this peak spread. The beacon may be an omnidirectional
Omnidirectional
Omnidirectional refers to the notion of existing in every direction. Omnidirectional devices include:* Omnidirectional antenna, an antenna that radiates equally in all directions* VHF omnidirectional range, a type of radio navigation system for aircraft...

 flashing xenon strobe
Strobe light
A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. It is one of a number of devices that can be used as a stroboscope...

, or it may rotate at a constant speed which produces the visual effect of flashes at regular intervals. Flashes may be of just a single color, or of two alternating colors.

In the United States, the Federal Aviation Administration
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...

 (FAA) has established the following rules for airport beacons:

Flashing rates
  1. 24 to 30 per minute for beacons marking airports, landmarks, and points on Federal airways
  2. 30 to 45 per minute for beacons marking heliports


Color combinations
  1. White and Green — Lighted land airport
  2. Green alone* — Lighted land airport
  3. White and Yellow — Lighted water airport
  4. Yellow alone* — Lighted water airport
  5. Green, Yellow, and White — Lighted heliport
  6. White, White, Green* — Military Airport
  7. White, Green, Red — Hospital and/or Emergency Services Heliport

*Green alone or yellow alone is used only in connection with a white-and-green or white-and-yellow beacon display, respectively.


Military airport beacons flash alternately white and green, but are differentiated from civil beacons by two quick white flashes between the green flashes.

In Class B
Controlled airspace
Controlled airspace is an aviation term used to describe airspace in which ATChas the authority to control air traffic, the level of which varies with the different classes of airspace. Controlled airspace is established mainly for three different reasons:...

, Class C
Controlled airspace
Controlled airspace is an aviation term used to describe airspace in which ATChas the authority to control air traffic, the level of which varies with the different classes of airspace. Controlled airspace is established mainly for three different reasons:...

, Class D
Controlled airspace
Controlled airspace is an aviation term used to describe airspace in which ATChas the authority to control air traffic, the level of which varies with the different classes of airspace. Controlled airspace is established mainly for three different reasons:...

 and Class E
Controlled airspace
Controlled airspace is an aviation term used to describe airspace in which ATChas the authority to control air traffic, the level of which varies with the different classes of airspace. Controlled airspace is established mainly for three different reasons:...

 surface areas, operation of the airport beacon during the hours of daylight often indicates that the ground visibility is less than 3 miles and/or the ceiling is less than 1,000 feet. Regardless of the weather conditions, the FAA has no regulation that requires airports to turn the beacon on during the day.

At some locations with operating control towers, Air Traffic Control (ATC) personnel turn the beacon on or off with controls in the tower. At many airports the airport beacon is turned on by a photoelectric cell
Solar cell
A solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect....

or time clocks, and ATC personnel cannot control them.

In Canada the regulations are much simpler. Lighted aerodromes are equipped with white single flash beacons operating at a frequency of 20 to 30 flashes per minute. Heliports with beacons exhibit the morse letter H (4 short flashes) at a rate of 3 to 4 groups per minute.
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