Transcontinental Airmail

United States Contract Air Mail routes 1925–1930. The numbers on the routes are the Contract Air Mail (CAM) route numbers. The original, government-run transcontinental route is shown in a thicker, lighter-coloured, dotted line running East–West between San Francisco and New York.

Comrade Misfit furnished a link and down the rathole I go, wherein I eventually came across this story by John Schamel about how coast-to-coast airmail got started. It's just a little nuts. I found it on a couple of different sites, but because I didn't like the formatting I made my own copy which is more readable.

In the midst of this story I found this paragraph where he talks about beacons.

What resulted was the first ground based civilian navigation system in the world. Beacons were positioned every ten miles along the airway. At the top of a 51-foot steel tower was a 1 million candlepower-rotating beacon. Pilots could see the clear flash of light from a distance of 40 miles. Also at the top of the tower were two color-coded 100,000 candlepower course lights. These pointed up and down the airway. They were colored green, signifying an adjacent airfield, and red, signifying no airfield. The course lights also flashed a Morse code letter. The letter corresponded to the number of the beacon within a 100-mile segment of the airway. To determine their position, a pilot simply had to remember this phrase – “When Undertaking Very Hard Routes, Keep Direction By Good Methods” – and know which 100-mile segment they were on.

 Now why would they choose that particular sequence of letters? Let's see what the Morse Code actually looks like.


Looks like they picked codes that had some kind of rough approximation to the numbers. They also have the advantage of being shorter than numbers. Numbers in Morse code are all five blips, none of these has more than four.

I suspect that the erection of these towers caused several locations to be christened 'Beacon Hill'.