Airport Rotating Beacon

An airport rotating beacon is an electrical rotating light assembly that is installed on the highest point of an aerodrome or airport. Pilots use beacon lights to identify the type of airport at night or with low visibility during the day. Beacon lights are identified by pilots according to the color of light.

Pilots cannot depend entirely on the airport beacon’s operation to determine whether weather conditions are IFR or VFR. An aerodrome beacon or aeronautical beacon is a device that is a vital component of night lighting at airports. 

When were the first rotating beacons used?

Early on in the history of aviation, airmen did not have sophisticated cockpit instruments and flashy airport lights to guide them through the night, hence flying during sundown used to be a near-impossible mission.

However, as airmail and military flight operations started gaining momentum in the early 20th century, it was vital to keep the service in the air. To aid with nighttime navigation, Lieutenant Donald Bruner lit the first airport beacons – bonfires. Quickly, the news about the efficiency of this navigational aid spread, when airmail pilot Jack Knight successfully landed his plane in pitch dark, only guided by the bonfires.

Short after this successful night flight, new electric lighting systems began springing around the American airports. While the beginning of the beacon implementation was slow, it quickly picked up pace in 1926 with Air Commerce Act and by 1933, around 1500 were in place around the country.

What is the function of beacon lights?

A beacon is a type of visual navigation aid (NAVAID) that projects flashes of light as information to pilots in the sky. This high-beam lighting device is the simplest yet most effective means of visual communication with pilots. It’s just like a traffic signal in the sky that enables pilots to identify the location and type of airport. The FAA has developed a list of regulations for airport beacons in the United States.

Beacons marking airports, landmarks, and marks on federal airways flash at a rate of 24 to 30 times per minute. Beacons marking heliports flash at a rate of 30 to 45 times per minute. Military airports usually utilize beacons that create two fast flashes with alternating green flashes. Variations of colors help the flight crew in identifying the location and category of the airport by the color of light flash. Airport beacons are required for pilots attempting to land under VFR conditions.

Pilots learn the color spectrum and rotation of the beacon to identify the airport. An airport is identified by the color and flash of its beacon light. The following beacons are the most widely used worldwide:

• White and aviation green flashing lights for civilian land airports
• A water airport with flashing white and yellow lights
• Flashing green, yellow, and white lights for a helicopter
• Two swift white flashes followed by a green flash identify a military airport

If a beacon is turned on during the day, it means that the ceiling is less than 1000 feet and ground visibility is less than three statute miles. However, this practice is used by airports as a precaution and provides an extra layer of safety in communication between the cockpit crew and air traffic controllers. In Canada, the rules are a little distinctive. White single flash beacons with a rate of 20 to 30 flashes per minute are installed at lighted aerodromes.

Construction of airport beacon lights

Airport rotating beacon lights are required to be fitted at the topmost point of an airport. Therefore, it is necessary to construct the equipment with weatherproofing techniques. The casing of the lamp is designed to withstand strong winds, rainfall, snowfall, and even extreme heatwaves. 

A robust rotating beacon construction should be equipped with lubricated moving parts. A high light beam lamp of at least 400W that is mounted 180° apart. The lamp housing should be adjustable between 0° and 10° above the horizon. A decent beacon should have a visual range of approximately 80 kilometers or 50 miles.

Moreover, beacons are designed according to local airport requirements, i.e., a winter airport should have proper temperature withstanding features and a snow or dust cleaning system. 

Maintenance of airport beacons

Airport beacons are mounted at the highest point of the airport, so they are exposed to humidity, snowfall, rainfall, storms, and extreme temperatures. To keep the equipment working properly and safely, it is essential to maintain and inspect it regularly. A few essential maintenance procedures are regular inspection of equipment. During an inspection, the following steps should be followed.

• Ensure that only qualified personnel performs maintenance procedures
• Never install, uninstall, or maintain the equipment without first consulting the manufacturer’s maintenance manual
• Never use tools not listed in the maintenance manual
• Never make changes to original equipment unless specifically authorized by the manufacturer in the manual
• Do not use unspecified spare parts
• The equipment should be inspected at regular intervals
• Daily inspections include lamp functionality and beacon rotation
• Glass clearance is included in the bi-monthly inspection. If there is contamination, it should be cleaned
• Visual inspection of electrical connections is part of the annual inspection. The lamp should be replaced at an interval of 30,000 hours
• Only repaint the beacon using aviation gloss orange and white paint with non-fading properties.

FAQs

What does an airport rotating beacon mean?

An airport rotating beacon, also known as an aerodrome beacon or aeronautical beacon, is a beacon installed at an airport or aerodrome to identify its location to incoming pilots at night. Such beacons are mounted on top of other buildings at the airport, such as the control tower. It flashes different colors to inform pilots about the type of airport. 

Do airports still have rotating beacons?

Yes, all airports with runway edge lighting and all heliports are required to be equipped with a functional rotating beacon.

Who is in charge of turning the beacons on an off?

 If an airport has an operating control tower, the ATC staff can control the beacons and switch them on or off. However, in airports without the control tower, the beacons are controlled by photoelectric cells or timers.

When must an airport’s rotating beacon be on?

AC 150/5345-12F-Specification for Airport and Heliport Beacons is an FAA document that indicates that the rotating beacon must be on during the night and during low visibility in the daytime, airport beacon lights must be on and function properly. Daytime operation at airports does not always require the beacons to be on and it is often up to the air traffic control personnel whether they keep the flashes turned on.

What type of airport is indicated by a flashing white and green beacon?

Flashing white and green lights are used at commercial airports. The colors of the beacon light help pilots identify the airport from the sky.