Tens of thousands of flights were delayed or canceled around Christmas when frigid weather and storms made travel treacherous. But the weather was mostly fine on Wednesday morning when flights across the country were halted because the Federal Aviation Administration’s system to alert pilots to safety issues went down.
The F.A.A. said on Wednesday night that it had traced the outage to a damaged database file and that there was no evidence that it was caused by a cyberattack. The disruption was the latest example of serious problems in the aviation system and at the F.A.A., the agency responsible for safely managing all commercial air traffic that critics say has long been overworked and underfunded.
The pause on flights across the country highlighted what aviation experts say are glaring weaknesses at the agency, long considered the world’s premier aviation regulator. The F.A.A. has struggled to quickly update systems and processes, many of which were put in place decades ago, to keep up with technological advancements and a sharp increase in the number of flights and passengers.
Problems with the system used to notify pilots of hazards in the air and ground began on Tuesday night, forcing officials to reboot the system early Wednesday morning. To fix the problem, the F.A.A. ordered airlines to delay all departing flights just before 7:30 a.m. That pause was lifted at about 9 a.m., but the disruption was far from over as airlines struggled to get back to normal throughout the day. Delays cascaded throughout the system and, by the afternoon, about 9,000 flights had been delayed and 1,300 had been canceled.
Just two weeks earlier, hundreds of thousands of travelers were stranded by an operational meltdown at Southwest Airlines, the country’s largest carrier by number of passengers. Taken together, the two episodes underscore the fragility of the nation’s aviation system.
The F.A.A., in particular, has long faced criticism for failing to modernize its technological systems quickly enough and not hiring enough air traffic controllers and safety specialists. Lawmakers strongly criticized the agency’s oversight of Boeing, for example, after two of the company’s 737 Max planes crashed, killing 346 people in Indonesia and Ethiopia in 2018 and 2019.
A big part of the problem, aviation experts said, is that Congress has not given the F.A.A. enough money to do its many jobs properly, and the agency has sometimes been slow to make change even when it had enough resources. The agency’s budget was about $18.5 billion in 2022 — less than it was in 2004 after adjusting for inflation.
“This is an agency that has been chronically and critically underfunded, not for years, but for decades,” said William J. McGee, a senior fellow for aviation at the American Economic Liberties Project, a research and advocacy group that has criticized consolidation in the airline business.
The outage will surely figure prominently in hearings and debates in Congress because the F.A.A.’s most recent authorization, passed in 2018, expires this year. That gives lawmakers an opportunity to overhaul the agency, require changes and reset its funding. Many senators and representatives have expressed anger and concern about flight delays and cancellations since air travel began to recover in 2021 after collapsing in the first year of the pandemic.
“We will be looking into what caused this outage and how redundancy plays a role in preventing future outages,” Senator Maria Cantwell, Democrat of Washington and the chairwoman of the Senate Commerce Committee, said in a statement on Wednesday. “The public needs a resilient air transportation system.”
The F.A.A. is also without a permanent leader, and it is not clear when that will change. Last week, President Biden renominated his choice to lead the agency, Phillip A. Washington, the chief executive of Denver International Airport. Mr. Washington was nominated last year but did not receive a Senate confirmation hearing.
He has faced criticism over his limited aviation experience and his involvement in a public corruption investigation in Los Angeles, where he previously ran the Los Angeles County Metropolitan Transportation Authority. Mr. Washington has said he did nothing wrong.
The agency has lacked a permanent leader since the end of March, when Stephen Dickson, a former Delta Air Lines executive who was appointed by President Donald J. Trump, stepped down about halfway through a five-year term. Since then, Billy Nolen, the F.A.A.’s top safety official, has led the agency on an interim basis.
A spokeswoman for Ms. Cantwell said her committee had not yet scheduled a hearing to consider Mr. Washington’s nomination.
Pete Buttigieg, who oversees the F.A.A. as the secretary of transportation, said on Wednesday that the government was investigating what caused the outage and why the agency’s systems were not more resilient.
“When there’s a problem with a government system, we’re going to own it, we’re going to find it, and we’re going to fix it,” Mr. Buttigieg told reporters. “In this case, we had to make sure that there was complete confidence about the safety of flight operations, which is why there was the conservative but important step to have that pause and make sure everything was back up and running.”
Experts say that the F.A.A.’s technology has grown outdated and that the agency has long lacked the resources for ambitious overhauls that would strengthen those systems.
“I’ve been flying airplanes for 55 years, it’s been known for a long time that the F.A.A. is often underfunded,” Chesley B. Sullenberger III, the pilot who safely landed a US Airways plane on the Hudson River in 2009, said in a telephone interview on Wednesday as the flight he was traveling on was delayed.
Two decades ago Congress did launch a major overhaul of the national aviation system, known as the Next Generation Air Transportation System, or NextGen. The multibillion-dollar project, which is intended to allow airlines to operate more flights and modernize some of the aging technology used by the F.A.A., has been mired in problems and taken longer than expected.
In a 2021 report, the inspector general of the Transportation Department found that the benefits of the NextGen overhaul have fallen far short of early projections, but said that it still held promise. The project is supposed to help the agency handle increased air traffic and develop technology to prevent problems like Wednesday’s disruption.
“The expectations for these capabilities vastly exceeded the actual deliverables,” said Robert Mann, an airline industry expert and president of the aviation consultancy R.W. Mann and Company.
In recent years, the F.A.A. has fallen short in other areas, including not having enough air traffic controllers in some parts of the country at times. The airline industry and a union that represents controllers have said that staffing shortages have led to flight delays and cancellations.
Airline executives and union leaders say the air traffic control center in Jacksonville, Fla., in particular has been overwhelmed by flights. That issue has been compounded by bad weather, commercial space launches and other problems, Rich Santa, the president of the union, the National Air Traffic Controllers Association, said in a speech last summer.
“If you fly on the East Coast, if you come close to Florida, you are affected by this facility,” he said.
The agency launched a broad air traffic controller recruiting campaign last year, but the effort is unlikely to quickly resolve any staffing problems because hiring and training controllers can take months — and getting new hires to the right places can take even longer.
The agency also faced widespread criticism for failing to adequately ensure the safety of Boeing’s 737 Max jet after the two crashes. The F.A.A. had outsourced oversight to Boeing itself through a program where some regulatory work was delegated to company employees. That practice was allowed under federal law partly because the agency didn’t have the resources to do the work on its own.
Representative Nancy Mace, Republican of South Carolina, said the outage on Wednesday was particularly frustrating because it happened so soon after Southwest Airlines’ meltdown during the holidays.
Ms. Mace said Southwest and federal agencies should face the same tough scrutiny and that she intended to ask the F.A.A. questions about its shortcomings and how it planned to address them.
“The F.A.A. is putting safety first, which is important,” Ms. Mace said. “But also, at the same time, Americans should know they can take a flight on any random week of the year and know that they’ll get to their destination safely and securely.”
Kitty Bennett contributed research.