In the early days of air traffic control, separation between aircraft operating under what is known as “Instrument Flight Rules” (IFR) was accomplished by plotting the position of each aircraft using a large table and tiny wooden aircraft. As airplanes would report their position over radio, or their position was inferred from flight plans and elapsed time, controllers would move the little wooden airplanes across the table. If two of the wooden airplanes got too close to each other on the table, it was assumed that the real airplanes were also too close and attempts would be made to make contact with them and resolve the situation.
The system worked well and no real-world airplanes collided. It was, however, horrendously inefficient both in the use of airspace as well as of the controller’s time.
After WW II, technologies that had been developed to vanquish the enemy — RADAR in particular — found their way into civilian life. Computer systems originally developed to project ballistic trajectories and break Axis ciphers were adapted to track incoming Soviet nuclear bombers, creating the SAGE (Semi-Automatic Ground Environment) system (see sidebar).
Subsequently, the Civil Aeronautics Board (precursor to the FAA) obtained sets of war-surplus RADAR equipment and began deploying them across the United States. It was realized that using RADAR allowed air traffic control to automate the manual process of moving the wooden airplanes across the table. It was also realized that the information processing capability of the SAGE system could be adapted to tracking civilian airliners.
The combination of RADAR technology and the information processing capability of the SAGE system allowed a drastic increase in the capacity of the air traffic control system. At the same time, it also drastically reduced and automated the air traffic controller’s job -- gaining huge increases in personnel productivity and efficiency.
The mission of air traffic control, to separate aircraft operating under Instrument Flight Rules, has not changed one iota since the 1920s. The technology that they use to perform that separation, however, has changed. And the changing technology has been used not to do something different, but to do the same thing BETTER.
Because of the critical nature of air traffic control, the new technology was never incorporated to replace or disrupt the original work process. Only to augment it. Indeed, air traffic separation using RADAR and computers is, to this day, still referred to as “augmented operations” in the air traffic control manual. And the process of separating aircraft using wooden toys on a table is referred to as “normal operations” in that same manual. Air traffic controllers are taught first how to separate aircraft using paper, pencil, and pieces of wood on a table. And only when they show they can do that, are they allowed to use the augmented technology in their day-to-day work with the understanding that, if the technological excrement hits the fan — the networks go down, the computers go down, etc. they can in an instant revert to “normal operations” and drag out the tables and wooden airplanes.