Airmail routes continued to expand until the Transcontinental Mail Route was inaugurated. [Figure 1-5] This route spanned from San Francisco to New York for a total distance of 2,612 miles with 13 intermediate stops along the way. [Figure 1-6]
Figure 1-5. The de Haviland DH-4 on the New York to San Francisco inaugural route in 1921.
On May 20, 1926, Congress passed the Air Commerce Act, which served as the cornerstone for aviation within the United States. This legislation was supported by leaders in the aviation industry who felt that the airplane could not reach its full potential without assistance from the Federal Government in improving safety.
The Air Commerce Act charged the Secretary of Commerce with fostering air commerce, issuing and enforcing air traffic rules, licensing pilots, certificating aircraft, establishing airways, and operating and maintaining aids to air navigation. The Department of Commerce created a new Aeronautics Branch whose primary mission was to provide oversight for the aviation industry. In addition, the Aeronautics Branch took over the construction and operation of the nation’s system of lighted airways. The Postal Service, as part of the Transcontinental Air Mail Route system, had initiated this system. The Department of Commerce made great advances in aviation communications, as well as introducing radio beacons as an effective means of navigation.
Built at intervals of approximately 10 miles, the standard beacon tower was 51 feet high, topped with a powerful rotating light. Below the rotating light, two course lights pointed forward and back along the airway. The course lights flashed a code to identify the beacon’s number. The tower usually stood in the center of a concrete arrow 70 feet long. A generator shed, where required, stood at the “feather” end of the arrow.
Figure 1-6. The transcontinental airmail route ran from New York to San Francisco. Intermediate stops were: 2) Bellefonte, 3) Cleveland, 4) Bryan, 5) Chicago, 6) Iowa City, 7) Omaha, 8) North Platte, 9) Cheyenne, 10) Rawlins, 11) Rock Springs, 12) Salt Lake City, 13) Elko, and 14) Reno.