Guiding Airmail Flights Using Giant Arrows

Ad:

Long before the advent of radio navigation and Global Navigation Systems (GPS) to assist in air flight, the Transcontinental Airway System was developed to aid nighttime airmail flights.  Proposed by the National Advisory Committee for Aeronautics (NACA), the TAS was a series of beacons on concrete arrow platforms to form a sequential lighted airway stretching from the East Coast to the West Coast.  Prior to the establishment of the airway system, nighttime flight for carrying mail was all but impossible due to poor visibility and inclement weather.

Prior to the establishment of the Transcontinental Airway System, a good aviation charts were not available and pilots had to use visual clues to navigate across the United States.  To open up nighttime flying as a way to speed up cross-country mail service, lighted airway beacons were set up space on average ten miles apart (closer in more rugged terrain and further away on the plains).  The rotating beacons were 24 inches in diameter and were placed atop 53-foot towers.  The towers were anchored onto concrete arrows that were painted yellow, pointing to the next higher numbered beacon.  Brightly lit, the beacons were five million candlepower and powered by generators inside of small outbuildings next to the towers.  At the top of the beacons were two color-coded course lights: green indicating an adjacent airfield and red meaning no airfield.

Map from 1924 created by the US Post Office Department showing the First Transcontinental Air Mail Route stretching from New York to San Francisco.  The route, which opened on July 1, 1924, marked the start of both day and night time air flights.

Map from 1924 created by the US Post Office Department showing the First Transcontinental Air Mail Route stretching from New York to San Francisco. The route, which opened on July 1, 1924, marked the start of both day and night time air flights.

The first nighttime flights using the Transcontinental Airway System began on July 1, 1924.  By removing the need for the transfer of mail to rail cars at night, mail delivery time from the East Coast to the West Coast was reduced by two days. By 1933, 18,000 miles of lighted airways had been established with 1,550 rotating beacons, and 236 airfields.

The emergence of radio navigation and radar in the 1930s eventually removed the need for nighttime lighted airways for navigation.  The beacons were decommissioned by the Department of Commerce in the 1940s.  The steel towers were disassembled and repurposed, leaving only the arrow markers in place.  Many of these concrete arrows are still in place around the country.

While many a hiker and tourist has come across these abandoned markers on trip around the country, armchair geographers can viewed a map of geolocated airway beacon sites on Google Maps.  If you want to explored the GIS data for historic airway beacons, you can download a KML file from the page.

Historic airway beacon located in Utah.

Historic airway beacon located in Utah.

References

Schamel, John. “Night Navigation.” Night Navigation. N.p., 02 Sept. 2012. Web. 06 Dec. 2013. <http://www.atchistory.org/History/nightnav.htm>.

Spivey, Brenda J. “Airway Beacons: An Integral Part of Montana’s Night VFR Navigational System: Past History, Present Service, and Present Value.” (n.d.): n. pag. Web. 6 Dec. 2013. <http://www.eaa517.org/newsletters/AirwayBeacons.pdf>.


Advertising



Like this article and want more?

Enter your email to receive the weekly GIS Lounge newsletter:

Advertising