An airway beacon (US) or aerial lighthouse (UK and Europe) was a rotating light assembly mounted atop a tower. These were once used extensively in the United States for visual navigation by airplane pilots along a specified airway corridor. In Europe, they were used to guide aircraft with lighted beacons at night. [1] [2]
A network of aerial lighthouses was established in the United Kingdom and Europe during the 1920s and 1930s. [3] Use of the lighthouses has declined with the advent of radio navigation aids such as NDB (non-directional beacon), VOR (VHF omnidirectional ranging) and DME (distance measuring equipment). The last operational aerial lighthouse in the United Kingdom is on top of the cupola over the RAF College main hall at RAF Cranwell.[ citation needed ]
In the Netherlands, gas holders were painted with an arrow pointing north and two letters identifying their location.
Approximately 1,500 airway beacons were constructed to guide pilots from city to city, [4] [5] covering 18,000 miles (29,000 km). Today, most of the beacons have been removed, but the State of Montana continues to maintain several as navigation aids in mountainous terrain. [6] One beacon is preserved for historical purposes in Saint Paul, Minnesota [7] at the Indian Mounds Park on a bluff overlooking the Mississippi River. [8] A rotating airway beacon has been in continuous operation at the summit of Rocky Butte in Portland, Oregon since 1929, though it was officially decommissioned during the 1960s. Recently, the beacon at Grants, New Mexico was restored for historic preservation, using original items found at other nearby sites. [9]
A large concrete slab, in the shape of an arrow, was located near the base of each beacon. Many of these arrows remain today, some of which are visible from satellite pictures, even in urban settings. [10]
An airway beacon has two distinct light characteristics: A revolving narrow white light beam about 5 degrees wide in azimuth and a set of fixed colored course lights of about 15 degrees width. [11]
The rotating beacon 24 inch (610 mm) parabolic mirror and a 110-volt, 1 kilowatt lamp. [11] spinning at 6 rpm, creating a quick one-tenth second flash every ten seconds. In clear weather they could be seen for 40 miles (64 km). [11] [12] Montana took steps to modernize their beacons, encasing newer light systems in clear domes. [13]
Just below the white beacon, a set of red or green course lights point along each airway route. Red lights denote an airway beacon between landing fields while green denotes a beacon adjacent or upon a landing field. [11] These course lights flash a Morse code letter identifying the beacon to the pilot. Each beacon is identified with a sequential number along the airway, and flash the red or green course lights with the Morse code ID of one of 10 letters: W, U, V, H, R, K, D, B, G or M. The letters represent the digits of 1 through 10 (W = 1, ..., M = 10). [11] The course lights turn on for 0.5 second for a dot, 1.5 second for a dash with a 0.5 second between each dot or dash. A pause of 1.5 seconds separates each letter. [14]
To help remember the letters and their sequence number, pilots memorized the following: "When Undertaking Very Hard Routes, Keep Direction By Good Methods." The beacons are depicted on navigation charts along with their number and Morse code pattern. For example, beacon number 15 would have a code digit of 5 (the units digit), hence the letter R, and Morse code: "dit dah dit" (·−·). [15]
Airway beacons in the US were constructed by the Post Office and the Department of Commerce between 1923 and 1933. [12] The Low Frequency Radio Range system began to replace this visual system in 1929. [12] The last visual airway beacon was supposedly shut down in 1973, [12] but a few airway beacons are still operating in Portland, Oregon and Western Montana. [16] Those in Montana are charted on the Great Falls sectional chart. [17] Montana was the last state to officially maintain airway beacons, through the state's Aviation Division. In 2017, the decision was made by Aeronautics Division to discontinue their maintenance of the system, due to the system's obsolete nature and budgetary concerns. The system was to be shut down entirely by December 31, 2021. [18] In spring of 2018, fourteen of the seventeen beacons were shut down by MDT. The Montana Department of Transportation's Communications Bureau took over care of beacons at St. Regis and Lookout Pass. Six beacons are now in the care of the owners of the land they were erected on, six are in the care of a non-profit, Idaho Aviation Heritage, and four are in the care of local governments. [18] Due to their historical significance in the state, the beacons at Homestake Pass, Canyon Resort, MacDonald Pass, Silver Bow, Spokane, Lookout Pass, St. Regis, Whitetail are in the process of being listed on the National Register of Historic Places. The strawberry Mountain beacon was demolished in the summer of 2021. MDT's Aeronautics Division removed the beacon and donated to the Montana Historical Society. [18]
A waypoint is an intermediate point or place on a route or line of travel, a stopping point or point at which course is changed, the first use of the term tracing to 1880. In modern terms, it most often refers to coordinates which specify one's position on the globe at the end of each "leg" (stage) of an air flight or sea passage, the generation and checking of which are generally done computationally.
In aviation, the instrument landing system (ILS) is a precision radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. In its original form, it allows an aircraft to approach until it is 200 feet (61 m) over the ground, within a 1⁄2 mile (800 m) of the runway. At that point the runway should be visible to the pilot; if it is not, they perform a missed approach. Bringing the aircraft this close to the runway dramatically increases the range of weather conditions in which a safe landing can be made. Other versions of the system, or "categories", have further reduced the minimum altitudes, runway visual ranges (RVRs), and transmitter and monitoring configurations designed depending on the normal expected weather patterns and airport safety requirements.
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Articles related to aviation include:
A non-directional beacon (NDB) or non-directional radio beacon is a radio beacon which does not include inherent directional information. Radio beacons are radio transmitters at a known location, used as an aviation or marine navigational aid. NDB are in contrast to directional radio beacons and other navigational aids, such as low-frequency radio range, VHF omnidirectional range (VOR) and tactical air navigation system (TACAN).
An automatic direction finder (ADF) is a marine or aircraft radio-navigation instrument that automatically and continuously displays the relative bearing from the ship or aircraft to a suitable radio station. ADF receivers are normally tuned to aviation or marine NDBs operating in the LW band between 190 – 535 kHz. Like RDF units, most ADF receivers can also receive medium wave (AM) broadcast stations, though these are less reliable for navigational purposes.
Very High Frequency Omnidirectional Range Station (VOR) is a type of short-range radio navigation system for aircraft, enabling aircraft with a receiving unit to determine its position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons. It uses frequencies in the very high frequency (VHF) band from 108.00 to 117.95 MHz. Developed in the United States beginning in 1937 and deployed by 1946, VOR became the standard air navigational system in the world, used by both commercial and general aviation, until supplanted by satellite navigation systems such as GPS in the early 21st century. As such, VOR stations are being gradually decommissioned. In 2000 there were about 3,000 VOR stations operating around the world, including 1,033 in the US, but by 2013 the number in the US had been reduced to 967. The United States is decommissioning approximately half of its VOR stations and other legacy navigation aids as part of a move to performance-based navigation, while still retaining a "Minimum Operational Network" of VOR stations as a backup to GPS. In 2015, the UK planned to reduce the number of stations from 44 to 19 by 2020.
A navigation light, also known as a running or position light, is a source of illumination on a watercraft, aircraft or spacecraft, meant to give information on the craft's position, heading, or status. Some navigation lights are colour-coded red and green to aid traffic control by identifying the craft's orientation. Their placement is mandated by international conventions or civil authorities such as the International Maritime Organization (IMO).
The Air Commerce Act of 1926 created an Aeronautic Branch of the United States Department of Commerce. Its functions included testing and licensing of pilots, certification of aircraft and investigation of accidents.
In the United States, airways or air routes are defined by the Federal Aviation Administration (FAA) in two ways:
A NOTAM is a notice filed with an aviation authority to alert aircraft pilots of potential hazards along a flight route or at a location that could affect the flight. NOTAMs are notices or advisories that contain information concerning the establishment, conditions or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which may be essential to personnel and systems concerned with flight operations.
A marker beacon is a particular type of VHF radio beacon used in aviation, usually in conjunction with an instrument landing system (ILS), to give pilots a means to determine position along an established route to a destination such as a runway.
An aerodrome beacon, airport beacon, rotating beacon or aeronautical beacon is a beacon installed at an airport or aerodrome to indicate its location to aircraft pilots at night.
Aviation obstruction lighting is used to enhance the visibility of structures or fixed obstacles which may conflict with the safe navigation of aircraft. Obstruction lighting is commonly installed on towers, buildings, and even fences located in areas where aircraft may be operating at low altitudes. In certain areas, some aviation regulators mandate the installation, operation, color, and/or status notification of obstruction lighting. For maximum visibility and collision-avoidance, these lighting systems commonly employ one or more high-intensity strobe or LED devices which can be seen by pilots from many miles away from the obstruction.
Willows-Glenn County Airport is a county-owned, public-use airport located one nautical mile (2 km) west of the central business district of Willows, a city in Glenn County, California, United States. This airport is included in the National Plan of Integrated Airport Systems for 2011–2015, which categorized it as a general aviation facility. It is also known as Willows-Glenn Airport.
The low-frequency radio range, also known as the four-course radio range, LF/MF four-course radio range, A-N radio range, Adcock radio range, or commonly "the range", was the main navigation system used by aircraft for instrument flying in the 1930s and 1940s, until the advent of the VHF omnidirectional range (VOR), beginning in the late 1940s. It was used for en route navigation as well as instrument approaches and holds.
The Transcontinental Airway System was a navigational aid deployed in the United States during the 1920s.
An aerobeacon is a light assembly used to create a fixed or flashing signal visible over long distances. It consists of a high intensity electric lamp mounted with a focusing device in a cylindrical housing, which usually is rotated on a vertical axis by an electric motor. The sweep of the narrow beam thus produced gives the flashing effect. Aerobeacons were originally developed for aviation use, mostly as aerodrome beacons, but they also saw extensive use in lighthouses. They were far less expensive to manufacture and maintain than classic glass Fresnel lenses, and much more durable; they could be mounted and exposed to the weather. Historic models include the DCB-24, which used a single parabolic reflector; the DCB-224, a double-beamed version of the DCB-24; and the DCB-36, which used a system of plastic Fresnel type lenses. Manufacturers included Carlisle & Finch in Cincinnati and the Crouse-Hinds Company in Syracuse, New York. Aerobeacons have replaced fragile glass Fresnel lenses in many lighthouses and are still widely used in other applications.
Semaphore is the use of an apparatus to create a visual signal transmitted over distance. A semaphore can be performed with devices including: fire, lights, flags, sunlight, and moving arms. Semaphores can be used for telegraphy when arranged in visually connected networks, or for traffic signalling such as in railway systems, or traffic lights in cities.
A Pundit Beacon or Landmark Beacon was an airfield navigational and identification beacon, used by the British Royal Air Force (RAF) in the period around World War II.
The Lindbergh Beacon, an aircraft beacon atop the Los Angeles City Hall, operated nightly from April 26, 1928, until just after the attack on Pearl Harbor. It was restored to its original condition in 2001, and Los Angeles magazine described it as "a tiara of light atop our beautifully restored Los Angeles City Hall." City officials now occasionally put the beacon into operation for special occasions such as the year-end holidays.
Today, Montana is the only state that still utilizes part of this historic network through our rugged western mountains. Division personnel climb and maintain approximately 19 of these beacons on a regular schedule, also providing ownership and ground leases for their operation.
All of our airway beacons and the associated code are listed on any current Great Falls sectional[. . .]
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