The outage occurred overnight on Tuesday and U.S. flights were slowly beginning to resume departures on Wednesday.
"We will be looking into what caused this outage and how redundancy plays a role in preventing future outages. The public needs a resilient air transportation system," Cantwell said. The ground stop was lifted by the FAA shortly before 9 a.m. EST.
Many lawmakers from both parties urged action to prevent a future disruption.
Senator Ted Cruz, the incoming top Republican on the committee, said, "The FAA's inability to keep an important safety system up and running is completely unacceptable ... The administration needs to explain to Congress what happened, and Congress should enact reforms in this year's FAA reauthorization legislation."
The FAA authorization is due to expire on Sept. 30 and the outage may put pressure on Congress to complete action. Lawmakers have routinely extended the FAA legal authority to operate before reaching agreement on a reauthorization. Those bills are typically used for major reforms to aviation policy.
The FAA has been without a permanent administrator since March 31. The Senate Commerce Committee has yet to hold a hearing on President Joe Biden's pick to head the agency, Denver International Airport Chief Executive Phil Washington, who was renominated by Biden last week.
Washington has faced criticism from Republicans after he was named in a search warrant tying him to corruption allegations at the Los Angeles County Metropolitan Transportation Authority.
U.S. Representative Garret Graves, who was the top Republican on the House Transportation aviation subcommittee last year, said on Wednesday that the FAA failure "has wreaked havoc across the country ... This past year has made clear that significant improvements across the aviation system are needed. We will aggressively pursue accountability and craft reforms that focus on enhancing the passenger experience."
(Reporting by David Shepardson in Washington; Editing by Matthew Lewis)
By David Shepardson
