(CNN) — After the failure caused widespread disruption at US airports, operations have resumed after restoring a system that provides pilots with pre-flight safety warnings, the Federal Aviation Administration (FAA) said. Despite this announcement, thousands of flights across the country are being delayed.
“Routine US air traffic operations are gradually resuming following an overnight outage of the Notice to Air Missions system that provides safety information to flight crews,” the agency tweeted.
Update 5: Regular air traffic operations are gradually resuming across the United States following an overnight suspension of air travel notifications providing safety information to flight crews. Ground stop removed.
We are continuing to investigate the cause of the initial issue
— FAA ✈️ (@FAANews) January 11, 2023
The agency ordered a nationwide grounding of departures after discovering a failure in its NOTAM, or Notice to Air Missions, system. Shortly before 9 a.m. ET, the FAA lifted the order, saying air traffic operations would resume. In the same notice, he said he was trying to find out what caused the problem.
The Federal Aviation Administration’s NOTAMS, or Notices to Air Missions, system that failed Wednesday provides information that pilots should read before they fly.
However, as of Wednesday morning, airlines were still experiencing flight delays or cancellations due to congestion caused by the blackout. A source familiar with the situation said airlines may implement delay plans, which could lead to more scheduling problems.
The FAA site showed air traffic at New York’s LaGuardia Airport suspended at 10:05 a.m. ET. The site also showed delays at Charlotte Douglas International Airport in North Carolina, one of American Airlines’ largest hubs.
The Chicago Department of Transportation said operations at O’Hare and Midway have resumed, but there may be “remaining delays or cancellations.”
Airlines for America, an association representing US airlines, said early Wednesday that the outage was “causing significant operational delays.” Major US airlines, including United Airlines, Delta and American Airlines, announced flight cancellations as a result of the situation. United Airlines offers a travel discount to North America.
FlightAware, which tracks delays and cancellations, shows that as of 10:15 a.m. ET, more than 5,400 flights to and from the U.S. have been delayed and more than 900 have been canceled so far.
Earlier, the FAA said “some features are starting to come back online,” but said it will take time to figure that out. An earlier announcement said: “Technicians are currently working to restore the system and there is no estimate for service restoration at this time.”
“We are performing final validation checks and are now repopulating the system,” the FAA statement said. “Operations throughout the National Airspace System are affected. We will provide frequent updates as we progress.”
Transportation Secretary Pete Buttigieg tweeted earlier: “I contacted the FAA this morning regarding an outage affecting a critical system for providing safety information to pilots. The FAA is working to resolve this issue quickly and safely so air traffic can resume normal operations and will continue to provide updates.”
NOTAMS are used by commercial airline pilots to obtain real-time information on flight hazards and restrictions. The FAA stipulates that NOTAMS should not be relied upon as the sole source of information, so some aircraft may use other data to meet safety requirements.
The reason for the widespread blackout is still unclear
The affected system, Notices to Air Missions (NOTAM), sends alerts to pilots to inform them of conditions that could affect the safety of their flights. It is distinct from the air traffic control system, which keeps aircraft at a safe distance from each other, but is an essential tool for air safety.
US President Joe Biden said there was no immediate information on the cause of the blackout, the second US aviation crisis in as many weeks. He also said he had been briefed on the matter and contacted Transportation Secretary Pete Buttigieg.
“I talked to BoutiqueGeek,” he told reporters as he left the White House. “They don’t know why.” But I am talking to him on phone for last 10 minutes. I told them to inform directly when they know.”
He continued: “They don’t know what the cause is, they’re hoping they’ll get an idea in two hours about what the cause is and they’ll respond at that time.”
Asked if it was a cyber attack, Biden said: “They don’t know, they’ll find out.”
“Based on our discussions with the DOT/FAA there is no evidence of ‘foul play,'” a senior U.S. official familiar with the matter told CNN.
Earlier, White House spokeswoman Karine Jean-Pierre said in a statement that “there is no evidence at this time that a cyberattack has occurred,” but Biden ordered a Transportation Department investigation.