WASHINGTON, Jan 11 (Reuters) – U.S. flights were slowly beginning to resume departures and a ground stop was lifted after the Federal Aviation Administration (FAA) scrambled to fix a system outage overnight that had forced a halt to all U.S. departing flights.
The cause of the problem with a pilot-alerting system, which delayed thousands of flights in the United States, was unclear, but U.S. officials said they had so far found no evidence of a cyberattack.
The outage occurred at a historically slow time for U.S. travel after the December holiday travel season, but airlines have said demand remains strong as travel continues to recover to near pre-pandemic levels.
“Normal air traffic operations are resuming gradually across the U.S. following an overnight outage to the Notice to Air Missions system that provides safety info to flight crews. The ground stop has been lifted. We continue to look into the cause of the initial problem,” the FAA Tweeted.
The number of flights impacted continued to steadily rise even after the ground stop was canceled. One issue airlines are facing is trying to get planes in and out of crowded gates, which is causing further delays.
More than 5,400 flights had been delayed and 900 canceled according to the FlightAware website as officials said it will take hours to recover from the halt to flights.
The FAA had earlier ordered airlines to pause all domestic departures after its pilot alerting system crashed and the agency had to perform a hard reset around 2 a.m., officials said.
The FAA is expected to implement a ground delay program in order to address the backlog of flights halted for hours. Flights already in the air had been allowed to continue to their destinations during the ground stop.
U.S. President Joe Biden ordered the Transportation Department to investigate the outage and said the cause of the failure was unknown at this time. Asked if a cyber attack was behind the outage, Biden told reporters at the White House, “We don’t know.”
Transportation Secretary Pete Buttigieg pledged a “process to determine root causes and recommend next steps.”
Chicago-based United said it has resumed operations, but warned customers might continue to see some delays and cancellations.
Shares of U.S. carriers initially fell in Wednesday’s premarket trading, but most rallied after the market opened to positive territory as flights resumed.
Southwest Airlines (LUV.N) was down 0.17%, while Delta Air Lines Inc (DAL.N), United Airlines (UAL.O) and American Airlines (AAL.O) were up 1.1%, 1.5% and 0.4%, respectively. JetBlue (JBLU.O) also gained.
A trade group representing the U.S. travel industry, including airlines, called the FAA system failure “catastrophic.”
“America’s transportation network desperately needs significant upgrades,” Geoff Freeman, president of the U.S. Travel Association, said in a statement. “We call on federal policymakers to modernize our vital air travel infrastructure.”
Senate Commerce Committee chair Maria Cantwell said the panel would investigate. “We will be looking into what caused this outage and how redundancy plays a role in preventing future outages,” she said. “The public needs a resilient air transportation system.”
FAA’s system outage comes weeks after an operational meltdown at Southwest at the end of last year left thousands of passengers stranded.
A severe winter storm right before Christmas, coupled with the Texas-based carrier’s dated technology, led to over 16,000 flight cancellations last month.
The DOT, FAA’s parent agency, criticized Southwest’s failures and pressured the airline to compensate passengers. There is no legal requirement that the FAA must compensate passengers for flight delays caused by agency computer issues.
A NOTAM is a notice containing information essential to personnel concerned with flight operations but not known far enough in advance to be publicized by other means. A ground stop is an air traffic control measure that slows or halts aircraft at a given airport.
Information can go up to 200 pages for long-haul international flights and may include items such as runway closures, bird hazard warnings and construction obstacles.
United Airlines (UAL.O) said it had temporarily delayed all domestic flights and would issue an update when it learned more from the FAA.
Germany’s Lufthansa and Air France both said they were continuing to operate flights to and from the United States, while the French airline said it was monitoring the situation.
Earlier this month, a problem with a different airline computer control system delayed dozens of flights in Florida.
A total of 21,464 flights are scheduled to depart airports in the United States on Wednesday with a capacity of nearly 2.9 million passengers, data from Cirium shows.
American Airlines has the most departures from U.S. airports with 4,819 flights scheduled, followed by Delta and Southwest, Cirium data showed.
Live: View of flights taking off from Ronald Reagan Washington National Airport
Reporting by Doina Chiacu and David Shepardson in Washington, Abhijith Ganapavaram in Bengaluru, Jamie Freed in Sydney and Rajesh Kumar Singh in Chicago; Additional reporting by Nathan Gomes and Steve Holland in Washington
Writing by Shailesh Kuber and Alexander Smith Editing by Edmund Blair and Nick Zieminski
Our Standards: The Thomson Reuters Trust Principles.