Air Traffic Control Systems Are Outdated. What’s Being Done to Prevent Another Outage?

Transportation Secretary Sean Duffy on Saturday blamed the previous day’s nationwide ground stop on the replacement of copper wires at a “remote” Federal Aviation Administration (FAA) facility. Installing new fiber optic lines led to critical communication breakdowns, he said.About 7,500 flights were delayed and over 9,000 were canceled on Friday, according to FlightAware. Some 1.5 million passengers were scheduled to take off from airports in the U.S. after 4 p.m. Eastern, shortly after the ground stop began.The incident raised questions about what might have led to the historic event—only the second nationwide ground stop since 9/11—and what authorities were doing to prevent it from happening again.“What we’re working to determine is whether we had incompetence or did they install a faulty router,” Duffy said Saturday, which saw nearly 6,000 additional flights canceled.As investigators continued working to pinpoint the source of the problem, FAA Administrator Bryan Bedford told reporters in Washington, D.C., that disrupted flight schedules were expected to return to normal by the end of Sunday and promised that the “worst is behind us.”While that may be true for this specific outage, Duffy warned Friday that what happened was not an isolated incident and said that outages would likely continue to occur until antiquated communications equipment across the FAA’s air traffic control network was brought up to date.“It was the old legacy equipment. It failed,” Duffy said. “And listen, it’s going to continue to fail.”The Transportation Secretary went on to call for Congress to provide $50 billion before the end of the year to upgrade air traffic control and airport infrastructure, increasing the administration’s recent $30.1 billion request, which included $10.1 billion specifically for air traffic control modernization.There is reason to believe, however, that financial support alone will not solve the problems currently faced by the FAA. Those include shortages in fully certified air traffic controllers, weaknesses in planning and coordinating necessary modernization work, and vulnerabilities to cybersecurity threats. TIME has reached out to Duffy’s office for comment.Modernizing the FAA’s air traffic control system has been a goal of the industry for years, says Edward Booth, an aviation attorney and pilot based in Jacksonville, and billions of dollars have already been sunk into the process.“There has been a very methodical four-part, four-stage plan to upgrade that,” Booth tells TIME, referencing NextGen, a multibillion-dollar FAA modernization initiative dating to 2003. It has included shifting toward satellite-based aircraft tracking, digital communications, and more efficient flight routes. Booth says a major focus of those earlier modernization efforts was making more efficient use of airspace.“They have tried to squeeze more airplanes into limited space, make better use of the limited runways available in the system, and they started with completely changing the way airplanes are tracked in the world. It's a world standard now,” he says, pointing to how NextGen has already made strides in air travel.The agency’s newer overhaul builds on earlier modernization work and includes replacing aging communications equipment, radar, and other infrastructure, with its first phase targeted for completion by the end of 2028.“It's a very highly technical, robust system,” Booth says of the National Airspace System (NAS), “but it seems the weak spot was discovered yesterday afternoon.”What’s been done to modernize air traffic control—and what remains?For more than two decades, the FAA has been working to modernize the NAS while fighting an uphill battle against aging infrastructure. The average U.S. air traffic control tower was 40 years old, and most radar systems were approaching that age, House Transportation and Infrastructure Committee Chairman Sam Graves wrote in a May 2025 op-ed.Congress had already ordered an independent review of the FAA’s aging technology: The FAA Reauthorization Act of 2024 required an audit of legacy systems deployed before 2000—including their vulnerability to single-point failures—and a plan to accelerate replacement or improvement of those found to pose risks. In a written response to Congress, the FAA said that nonprofit research organization MITRE completed the audit in August 2025. The response said the findings would guide modernization efforts, but did not disclose the specific findings or resulting actions.In July 2025, Congress approved $12.5 billion for the FAA to upgrade its “radar, software, hardware, and telecommunications” at more than 4,600 sites through December 2028. As of Nov. 5, the FAA said it has “replaced 69% of copper wires, installed Surface Awareness Initiative (SAI) systems at 143 towers, transitioned 26 towers to electronic flight strips [and] installed 226 IP Voice Switches.”The updates were noted within an announcement saying the FAA was beginning to phase out the floppy disks used in air traffic control. It said that it had launched a replacement system that would include a digital display board with data about disruptions, weather conditions, and advisories. The announcement identified five initial facilities and set a goal of installing the system at 435 sites by the end of 2028.Duffy called these efforts “the latest signal that America’s brand new air traffic control system is coming at lightning speed.”The FAA then announced Nov. 10 that it was expanding its AI-powered scheduling and flight-planning tool—known as SMART (Strategic Management of Airspace, Routes, and Trajectories)—to airspace managed by all 22 Air Route Traffic Control Centers nationwide. SMART is part of a 12-year, $875 million contract that also covers the agency’s Flow Management Data and Services program.Duffy said at Friday’s press conference that SMART had nothing to do with the disruption.Why can one equipment failure cause widespread disruption?Describing Friday's outage, Duffy said a router being replaced as workers switched from copper wiring to fiber-optic connections began flooding other routers with more than 1,000 connection attempts every four to five seconds, disrupting communications and some radar feeds. Systems came back online after officials isolated the work at the remote location, he said.For Booth, the spread of that disruption underscores the need for safeguards that can contain a problem in one part of the FAA’s communications network before it affects the wider system. “They need a system that is not prone to single-point failures,” he says.Booth pointed out that legacy systems—often relying on analog lines, decades-old routers, and interconnected regional hubs—lack the fault-tolerant design needed to prevent a local or routine maintenance glitch from cascading nationwide.“The public probably would be shocked to learn that the way pilots communicate with air traffic control is tantamount to an old-fashioned telephone line,” he says. “You've got 10, sometimes 15 airplanes competing to talk to a single controller-specified frequency.”Kumar Sokka, the CEO of Acre Security, says a key consideration when upgrading complex systems is whether individual components can fail without disrupting the entire network.“Can you remove a single point of failure? Are these systems distributed in a way where it's siloed in certain structures where if something fails, not everything fails, right?” asks Sokka.He says that many industries come up against issues of balancing the high upfront expense of upgrading legacy systems against the severe financial and operational risks of future outages. Companies can overhaul different parts of their systems at different times, he says.“You can do it over time and not necessarily everything at once,” Sokka says. “You can get your software and the data modernized first so you can do preventative work of monitoring the health of a system constantly. And then over time, you can change out the hardware, because that’s the most expensive part.”Integrating new technology with older equipment presents its own challenges. At Friday’s briefing, Homeland Security Secretary Markwayne Mullin said new equipment had overwhelmed the older system, although the precise cause remained under investigation. “Nickel and diming it together does not work. This is what happens when that takes place,” he said.Duffy said that the FAA is working to get the travel ecosystem back on track in time for Thanksgiving, which is one of the busiest travel periods of the year in the U.S. According to Airlines for America, nearly 29 million passengers are expected to travel by plane between Nov. 20 and Nov. 30.