At the close of 1927, 1,572 pilots had been licensed and 2,573 others had applied for licenses. Additionally, 681 aircraft had been licensed for interstate commerce, and 908 aircraft had been assigned identification numbers. There were also 2,218 applications for license and identification of aircraft awaiting action.
It was at this time that the Department of Commerce issued its first Air Traffic Rules, as required under the Air Commerce Act of 1926.
These regulations required that all aircraft engaged in interstate or foreign commerce be licensed and marked with an assigned identification number. Pilots of licensed aircraft were required to hold private or commercial licenses. The regulations also prescribed operational and air traffic safety rules.
It’s interesting that the federal government decided to regulate traffic for such a small number of aircraft and pilots when at the same time there were more than 20 million cars on the road in the United States and no federal rules for their operation. Only state and local rules existed for automobile traffic.
It’s interesting to take a look at some of the 1927 Air Traffic Rules published by the Department of Commerce as Aeronautics Bulletin no 15.
Aircraft ﬂying in established civil airways, when it is safe and practicable, shall keep to the right side of such airways. In Figure 1, the railroad indicates the center of the airway. Planes A and B keep to the right of the side along which they are ﬂying, the interval between them never to be less than 500 feet. This also shows the manner of passing, when two planes are headed in opposite directions.
When two engine-driven aircraft are on crossing courses, the aircraft that has the other on its right side shall keep out of the way. Accordingly, A must keep out of B‘s way. The nearest it may approach is 300 feet from B. If there is sufficient space A may simply follow course A, which will bring him back of B, who will by that time have proceeded to B.
When two engine-driven aircraft are approaching head-on, or approximately so, and there is risk of collision, each shall alter its course to the right, so that each may pass on the left side of the other. This rule does not apply to cases where aircraft will, if each keeps on its respective course, pass more than 300 feet from each other. In this case, planes A and B alter their courses equally to bring a distance of at least 300 feet between them in passing.
An overtaking aircraft is one approaching another directly from behind or within 70° of that position, and no subsequent alteration of the bearing between the two shall make the overtaking aircraft a crossing aircraft within the meaning of the air trafﬁc rules, or relieve it of the duty of keeping clear of the overtaken craft until its ﬁnally past and clear.
Accordingly, B is an overtaking plane, as it approaches A at an angle of less than 70°. It must keep clear and allow A to proceed on its present course.
In case of doubt, B should assume that it is an overtaking craft and must keep clear by altering its course to the right, as shown, and not in the vertical plane.
When over-taking slower craft, he overtaking craft shall keep out of the way of the overtaken craft by altering its own course to the right, and not in the vertical plane. Thus, A would alter its course as shown in Figure 5 and overtake B, a slower plane, maintaining a minimum distance of 300 feet between them.
A. Upwind: Landings shall be made upwind when practical.
B. Course: If practical, when within 1,000 feet horizontally of the leeward side of the landing field, the airplane shall maintain a direct course toward the landing field.
C. Right over ground planes: A landing plane has the right of way over planes moving on the ground or taking off.
In addition to following the aerial rules of the road, the Air Commerce Regulations provided that “the owner or operator of every licensed aircraft shall keep a navigation and engine log book and shall quarterly transmit to the Secretary of Commerce a navigation summary report, in duplicate, showing the number of miles the aircraft has been flown during the quarter and the duration of the use of each engine. The log books shall be carried in the aircraft at all times when such is away from its home airport.
A GROWING FUTURE
These first air traffic rules were not only a harbinger of longer, more complex rules to come over the years, but also foretold the coming increase in aircraft and pilots.
Within two years of these first rules, there would be more than 12,000 aircraft licensed and nearly 10,000 pilots. Interest in aviation was growing at this time, as shown by the 12,000 student permits issued in 1929.