The U.S. Federal Aviation Administration (FAA) lifted a nationwide ground stop Friday evening after a communications system failure disrupted air travel across the country.
The four-hour shutdown caused thousands of flight cancellations and delays, marking the longest nationwide grounding of U.S. flights since the Sept. 11, 2001, terrorist attacks.
U.S. Transportation Secretary Sean Duffy said American airspace reopened at 8:15 p.m. ET. However, he warned that flights would resume gradually and it could take several days for airlines to return to normal operations.
More than 6,600 flights were cancelled and another 8,600 delayed, according to FlightRadar24. An additional 1,500 flights had already been cancelled for Sunday.
Duffy said tens of thousands of passengers were stranded at airports across the country.
The outage began around 3:36 p.m. after air traffic control centres experienced problems with radar and communications systems. Duffy said overloaded network equipment caused inconsistent data, forcing officials to shut down the system as a safety precaution.
He said radar and communications were never completely lost and that thousands of aircraft were able to land safely.
The transportation secretary said the immediate problem had been fixed and flying was safe. However, he warned that the country’s aging air traffic control system needs major upgrades to prevent future disruptions.
Duffy called on Congress to provide US$50 billion to modernize the system, blaming a lack of funding for delays in replacing outdated equipment.
Homeland Security Secretary Markwayne Mullin said there was no evidence so far that the outage was caused by a cyberattack or artificial intelligence system. However, investigators had not ruled out those possibilities.
The National Security Agency is assisting the Department of Homeland Security with the investigation.
Despite the ground stop being lifted, passengers continued to face long delays, cancellations and missed connections at airports across the country.
U.S. airlines will not be required to compensate passengers for the disruptions because the outages were caused by FAA systems rather than the airlines.
The incident has also raised concerns about the reliability of the country’s air traffic control infrastructure, which has faced ongoing problems with aging technology and a shortage of thousands of air traffic controllers.
