When getting mail from New York to San Francisco was a big deal and airline pilots still had to navigate by landmarks on the ground, an elaborate system of concrete arrows and high-powered beacons guided pilots safely—and speedily—across the country.See the concrete, almost covered by sage bushes? In the 1920s and '30s, that concrete was the primary means of navigation for airplane pilots delivering mail across the country.
Those concrete pads are arrows, pointing the right direction to fly before GPS—or even radio and radar—were available to aid in navigation. Here's how this creative system worked.
By the early 20th century, society and technology were moving quickly, but the mail still moved at a snail's (or train's) pace. It often took weeks for a letter to get across the country. In 1920 the U.S. Postal Service announced it would begin airmail service, and brave pilots soon began transporting mail the 3,000 miles between New York and San Francisco. Brave because pilots had no real way to navigate—even navigation maps didn't exist. Pilots had to navigate by landmarks on the ground, and couldn't fly at night or in bad weather.
In 1923 Congress approved a creative solution: 70-foot-long yellow concrete arrows spaced at 10-mile intervals, complete with a 50-foot tower in the middle of each arrow shining a million candle-power rotating beacon. Pilots could navigate by line-of-sight. There were 12 main stops between New York and San Francisco, along with emergency runways. All told 1,500 ground beacons were installed.
Each setup had the same concrete arrow and beacon, with additional lights lining the arrow. Each beacon flashed a unique code to identify its location. A generator shack sat at the back of the arrow to power the beacon.
After World War I, fighter pilots frequently worked delivering mail, but in the early years, the job was incredibly dangerous. Nearly 1 in 10 pilots died flying. The new navigation system made the job much safer.
It made it faster, too. Before the Transcontinental Airway System, the fastest
a letter ever travelled across the country was 83 hours, using a combination
of airplanes during the day and trains at night. After the navigation system,
that time was cut to 30 hours.Technology soon caught up with the Transcontinental Airway System, as radio and radar navigation improved. By World War II, the navigation stations were decommissioned, with the steel towers broken down and used in the war effort. Only the concrete arrows remained, paint slowly fading.
Today, the easiest way to find the arrows is by looking on Google Maps. The remaining arrows are mostly in the sparsely populated west, in states like Nevada, Utah and Wyoming.
Vegetation might be covering up the arrows but they are still there, pointing the way toward progress and the future.