A piece of aviation history hidden in the woods

By the time Charles Lindbergh’s nonstop flight across the Atlantic electrified the world in 1927, airmail was just becoming commonplace in the United States. In those days, delivering mail by air was not a profession for the faint of heart. Lindbergh himself worked briefly as an airmail pilot not long before his record-setting flight.

While traversing the Atlantic, Lindberg couldn’t use landmarks to mark his progress, so he relied on the difficult and sometimes inaccurate technique of “dead reckoning” — navigating with a compass and estimating his location based on speed and elapsed time. Early U.S. airmail pilots, particularly those flying at night or in bad weather, faced similar navigational challenges until the Post Office commissioned the Transcontinental Air Mail Route, a network of airway beacons designed to guide pilots across the largely featureless nighttime landscape.

Each lighthouse-like beacon consisted of a tower topped with a rotating light, a large concrete arrow pointing the way to the next beacon, and a brightly colored shed to house the generator that powered the light. The light produced flashes that could be seen by pilots up to 40 miles away. As a result, after dark or in bad weather, pilots could find their way across the country by flying from beacon to beacon — making airmail delivery a 24-hour operation and dead reckoning over large distances a thing of the past.  At its peak in the early 1930s, the airway beacon system included about 1,500 beacons and covered 18,000 miles.

One of these airway beacons was located atop Chestnut Ridge not far from ORNL’s Visitor Center. The beacon was constructed around 1920 as part of the Knoxville-to-Nashville airmail route. Because the area was relatively remote and primarily agricultural, it is thought that the beacon was maintained by a local farmer. Sometime in the 1930s, the beacon went out of use with the advent of radio navigation. A few years later, Chestnut Ridge and the surrounding land was bought by the federal government for the Manhattan Project, leaving the site undisturbed and eventually hidden by decades of forest growth.

The abandoned site was discovered in 2007 during clearing for an electrical transmission line. The beacon’s generator shed, the concrete pad for the fuel tank, and holes in the ground where concrete piers anchored the tower’s four legs are all that remain 100 years after the beacon’s construction. Presumably, the rest of the equipment was salvaged after the beacon was taken out of service.

In 2008, the site was cleared of brush, and the generator shed’s original bright yellow-and-black livery was restored. The effect of the facelift was striking. The brilliantly colored shed with its starkly geometrical black band bursts out of the landscape, giving visitors a sense of how distinctive airway beacons must have been from the air — even in the daylight — and illustrating and preserving a small piece of our nation’s aviation history.