Less than a week after Y2K passes without a global computer meltdown, a glitch in a 1960s computer at the air traffic control center in Washington, DC, slows and shuts down airlines in the Northeast.
Normally, when a flight is completed or a plane leaves a region’s airspace, the flight plan is deleted. A software glitch on this day meant the computer was no longer deleting the flight plans. As new flight plans came in, the system overloaded, and it shut down. So controllers went old-school, using small strips of paper with the flight information typed out. These slips were then hand-carried from one controller to another. This sneakernet system works just fine and is still used today as a backup. But it’s slower to walk across a room than to click a mouse, and the system ground to a crawl. Hundreds of flights from Boston, New York, Philadelphia, and Washington were directly affected, and that caused a ripple effect as waiting flights stacked up. Travelers around the country suffered nightmarish delays until the computer was fixed.
In the early days of aviation, pilots flew when conditions were good enough for them to see one another. By 1926, the United States started to implement rules for air traffic, and by 1930 the first radio-equipped control tower was installed in Cleveland. The first full-scale air traffic control center was established in Newark in 1936, the same year the federal government took over control of air traffic.
In the early days, controllers used a blackboard and maps with small models to estimate the locations of airplanes as reported by airports, the airlines, and radio operators along the routes. ATC modernized after World War II with the implementation of radar. U.S. controllers today combine radar, satellites, and good old-fashioned eyesight to keep track of more than eighty-five thousand flights a day. The Federal Aviation Administration plans to double air traffic capacity by switching from radar to GPS navigation.—JP