Airway Beacons

Beginning in 1923, the Post Office worked to complete a transcontinental airway of beacons on towers spaced 15 to 25 miles (24 to 40 kilometers) apart, each with enough brightness, or candlepower, to be seen for 40 miles (64 kilometers) in clear weather. On July 1, 1924, postal authorities began regularly scheduled night operations over parts of this route. In 1926, the Aeronautics Branch of the Department of Commerce took over responsibility for building lighted airways. By June 1927, 4,121 miles (6,632 kilometers) of airways had lights. By 1933, 18,000 miles (28,968 kilometers) of airway and 1,500 beacons were in place. The overwhelming majority of these beacon installations are now gone.

Typical airway beacon installation, 1931

Airway beacons featured a 24-inch parabolic mirror and a 110-volt, 1000 watt lamp producing 1,800,000 candlepower. In clear weather they could be seen for over 20 miles. The beacons rotated at six RPM, creating a flash every 10 seconds for 1/10th of a second. A well-maintained example of an airway beacon exists in St. Paul, Minnesota, USA, at Indian Mounds Park. The beacon installation shown below is in the desert Southwest of the USA and is not maintained.

One of the last existing engine generator sheds. This shed is on Federal land and protected by Federal law, as is the associated tower, shown below. Image Copyright © 2006 Dan Netcher, US BLM. All Rights Reserved.

Tower associated with the generator shed shown above. Image Copyright © 2006 Dan Netcher, US BLM. All Rights Reserved.

24-inch rotating assembly of an airway beacon. This particular beacon is displayed in front of the passenger terminal at the Twin Falls, Idaho, USA, airport. ("Joslin Field - Magic Valley Airport" KTWF) Copyright © 2006 Aviation Policy Institute, Inc. All Rights Reserved.

Indian Mounds, Minnesota

The last functional airway beacon in the United States, located in the Indian Mounds Park, St. Paul, Minnesota. Note the twin jet making a turn over the Gopher VOR. This beacon is situated just across the Mississippi River from the St. Paul Downtown Airport (KSTP) (just north of that airport) and just east of downtown St. Pau. The Minnesota State Capitol is visible from the base of the beacon as are the runways at KSTP. Copyright © 2007 Aviation Policy Institute, Inc. All Rights Reserved.

The beacon tower at Indian Mounds is set upon four concrete pads rather than a single slab. No generator building remains. Copyright © 2007 Aviation Policy Institute, Inc. All Rights Reserved.

The lamp is blocked by a metal panel on the north side of the structure to keep the light out of adjacent homes. Copyright © 2007 Aviation Policy Institute, Inc. All Rights Reserved.

All of these Indian Mounds Beacon images were captured on 1 May 2007.
Copyright © 2007 Aviation Policy Institute, Inc. All Rights Reserved.

Other Images

1941 Photo of five beacon rotating assemblies.

Beacon bulb and box in the collection of the Museum of Air Traffic Control. The bulb is quite large: approximately 9 inches x 2.5 inches (23 cm x 6.5 cm) including the base. Copyright © 2006 Aviation Policy Institute, Inc. All Rights Reserved.

The following text is copied from the Department of Commerce Lighthouse Service Bulletin, Vol. III, No. 37, Washington.  Dated January 3, 1927

AIRWAYS DIVISION

The Air Commerce Act of 1926, provides for the encouragement and use of aircraft in commerce, under the Secretary of Commerce. The work has been placed under the immediate supervision of the Assistant Secretary of Commerce for Aeronautics, William P. MacCracken, Jr., and four divisions have been established: Registration, Research, Airways, and Information.

In accord with the intent of Congress, that existing facilities of the department should be used so far as practicable in carrying out the provisions of the Air Commerce Act, the Airways Division has been set up as a part of the Lighthouse Service, and F.C. Hingsburg, on October 1, 1926, was appointed Chief Engineer, Airways Division. Mr. Hingsburg was previously Superintendent of Lighthouses on general duty, and has been connected with the Lighthouse Service since 1911.

Under the general supervision of the Assistant Secretary of Commerce for Aeronautics, the Airways Division will examine the airways, select emergency landing fields and beacon sites, erect structures, install the navigational aids, and thereafter maintain them. These activities are being carried out through some expansion of the Lighthouse Service, with additions as needed to its personnel, and under its district organization.

The airways to be established during the fiscal year 1927, are primarily those required by the air transport companies engaged in carrying mail under contract with the Post Office Department. These and other companies are developing express and passenger traffic. The principal advantage of air transportation is the saving of time. In order to make the saving of time most effective, night flying is essential, and the air navigation facilities being established on airways primarily provide the necessary lighting for night flying for carrying out the mail schedules established by the Post Office Department.

There are 9,475 miles of airways now in operation or proposed for the near future, of which 2,041 miles of the transcontinental airways are already lighted. Over 1,100 miles of additional lighted airways will be established during the calendar year 1928. Along the airways between airports, revolving searchlight beacons are established approximately 10 miles apart, and emergency landing fields are 40 to 50 acres in extent, having suitable runways of not less than 1,500 feet in length for the landing of aircraft. The fields are lighted by boundary lights spaced approximately 300 feet apart, showing the outline of the field from the air. A cable is carried around the field, furnishing electric current to the 15-watt lamps in the boundary standards. Red lights are mounted on all obstructions and green lights are used to show the best approach to the field. An internally lighted wind cone mounted on the airway beacon structure shows the direction and velocity of the wind. The airway beacon consists of a 24-inch revolving searchlight with 1,000-watt lamp, showing candlepower of approximately 2,000,000, with a flash every 10 seconds. The searchlight beacons are mounted on 50-foot skeleton windmill type towers and are automatic in operation by the use of a sun relay, where commercial power is available. Otherwise, farm lighting sets are used for generating electric current. The day mark consists of a concrete arrow 53 feet long pointing the direction along the airway. Each airway route carries a number, which is painted, conspicuously on one side of the gable roof of powerhouse buildings. Each beacon is numbered consecutively, and the designated number is likewise painted to show from the air for the identification of the structure. Part-time caretakers are employed locally to operate the engine generating sets and for the maintenance of emergency fields.

Quick Links

• The Evolution of Airway Lights and Electronic Navigation Aids

• Indian Mounds Park Airway Beacon

• Accident Report: TWA3, 16 January 1942. This is the crash near Las Vegas which killed Carol Lombard. Many airway beacons were not operational due to the war, and the probable cause of the accident lists the failure of the pilot to make use of the existing navigational aids.