By David Shepardson and Rajesh Kumar Singh
WASHINGTON/CHICAGO (Reuters) -U.S. airline operations returned to normal on Thursday even as the Federal Aviation Administration (FAA) investigates the cause of a computer outage that grounded flights nationally and seeks to prevent it from happening again.
More than 11,300 flights were delayed or canceled on Wednesday in the first national grounding of domestic traffic in about two decades. As of noon EST on Thursday, 1,400 U.S. flights were delayed and 117 were canceled, according to FlightAware, a typical aviation day given current weather issues.
Delta Air Lines, United Airlines, American Airlines Group Inc and Southwest Airlines Co all reported normal operations on Thursday.
Shares of American Airlines soared 9% in early afternoon trade after it forecast a higher fourth-quarter profit. Shares of United, Southwest, and Delta rose between 2% and 5%.
The FAA computer failure prevented airports from filing updated safety notices that warn pilots of potential hazards such as runway closures, equipment outages and construction, bringing flights to a temporary halt.
FAA officials said a preliminary review traced the problem to a damaged database file, but added there was no evidence of a cyberattack and the investigation was continuing.
The same file corrupted both the main system and its backup, said people familiar with the review, who asked not to be identified.
U.S. Senate Commerce Committee Chair Maria Cantwell, a Democrat, said the panel would investigate. Republican Senator Ted Cruz called the failure “completely unacceptable.”
“The modernization of the FAA will be expensive, and will be paid for through a combination of taxes on air travel that affect all carriers and efficiencies by larger airlines,” brokerage Bernstein said in a note.
A separate outage on Wednesday that temporarily prevented new safety notices from being received and disseminated digitally in Canada was caused by an isolated IT system failure, an industry source told Reuters.
NAV Canada, the country’s privately held air navigation service provider, has said it is investigating the cause, which is not believed linked to the United States.
Canadian flights were not affected by the NAV Canada outage since the new notices could be received and shared manually, such as by fax, phone, or normal frequencies.
“Existing NOTAMs remained accessible and our air traffic services staff and airports were able to relay any new information directly to operators,” a NAV Canada spokesperson said.
In the United States, Arjun Garg, former FAA chief counsel and acting deputy administrator, said it was premature to draw any conclusions about the event, but that the agency was right to ground flights.
Garg, now a partner at law firm Hogan Lovells, said the incident was a reminder that the FAA was subject to an annual appropriation cycle, making it difficult to plan and execute major multi-year projects such as air traffic control upgrades.
The FAA has been without a permanent administrator since March. The Senate has not held a hearing on President Joe Biden’s pick to head the agency, Denver International Airport Chief Executive Phil Washington, who was renominated last week.
Senators Jerry Moran and Amy Klobuchar spoke with acting FAA Administrator Billy Nolen about the outage and Nolen said “that his agency is working to determine what caused the breakdown to ensure it doesn’t happen again,” Moran said in a statement.
(Reporting by David Shepardson in Washington and Rajesh Kumar Singh in ChicagoAdditional reporting by Abhijith Ganapavaram, Nathan Gomes and Allison LampertWriting by Jamie FreedEditing by Nick Zieminski and Matthew Lewis)