Washington: The Federal Aviation Administration (FAA) grounded flights nationwide in the US on Friday afternoon for only the second time since the September 11 attacks, citing “extraordinary circumstances” caused by communications problems at regional air traffic control centres.
The country's top homeland security official attributed the disruption to a telecommunications outage and said there was no indication of a deliberate attack. However, the incident disrupted potentially thousands of scheduled flights through at least late Friday night, leaving passengers facing uncertainty over their travel plans.
“It's frustrating. This certainly sounds like it's going to be more than the usual run-of-the-mill delay. I look forward to finding out why,” said Jeff Dubner, a Washington, DC, attorney whose Alaska Airlines flight from Los Angeles to Washington was already half an hour late and taxiing towards the runway when it came to a halt.
The nationwide ground stop was the first since January 2023, when a key FAA computer system malfunctioned, and the second since the September 11, 2001, attacks.
Friday's restrictions were imposed “due to extraordinary circumstances and for reasons of safety”, according to an FAA notice. The agency was investigating a communications issue affecting the 22 regional air traffic control centres that direct planes travelling between airports across the country, Transportation Secretary Sean Duffy said.
A few international flights were taking off on Friday evening from major aviation hubs on the East and West coasts.
US Homeland Security Secretary Markwayne Mullin told reporters at the White House that there was no indication that the disruption was caused by a deliberate attack.
“It's just a telecommunications outage as of right now,” he said.
“Everybody's safe. There's no reason to be concerned about your loved ones if they're flying,” Mullin added.
At least 600 flights had been diverted following the FAA's order to ground air traffic nationwide.
As of 5.50 pm Eastern time, 496 flights had been diverted to the airports from which they originally departed, while 104 had been sent to different airports, according to aviation analytics company Cirium.
Among the airports receiving diverted flights were Chicago O'Hare International Airport, Denver International Airport, Dallas-Fort Worth International Airport and Ronald Reagan Washington National Airport.
Around 11,000 flights carrying more than 1.5 million passengers were scheduled to depart from US airports after 4 pm Eastern time, raising the likelihood of further cancellations and diversions.
At Chicago O'Hare Airport on Friday afternoon, passengers passing through security learnt about the ground stop from departure screens displaying widespread delays.
Some contacted friends and family, weighing whether to stay overnight in Chicago or find alternative ways to reach their destinations.
Amber McQuilkin, 27, was concerned that she might miss a trip with friends to New York for the League of Legends world finals. Her friends had already arrived, she said.
“There's not really any information being passed to me,” said the Seattle-based software engineer, who had taken a week off for the trip. “I contemplated just abandoning the flight and driving, but then the more I thought about it, the more I'm like, that would be miserable.”
Austin Curtis and his wife were reconsidering their journey from South Bend, Indiana, to a friend's baby shower in Denver after being delayed during a layover in Chicago.
They had boarded a flight to Denver at O'Hare International Airport when they were told to disembark.
“We did see them taking luggage off our plane and others, so we're assuming it's going to be a pretty substantial delay,” Curtis said.
The couple were unsure whether to book a hotel room or wait at the airport. With childcare already arranged for their two young children at home, they were considering spending the weekend in Chicago.
“We might just make the most of it,” Curtis said.
Despite the nationwide ground stop, SpaceX launched its Starship rocket from Texas on Friday afternoon for its latest test flight.
There was no timeline for the resumption of flights. Mullin said investigators would examine whether the disruption was linked to the FAA's nationwide rollout of a new artificial intelligence system designed to identify problems and recommend alternative routes for aircraft.
However, the system operates from a single location near Washington, DC, and sends recommendations to air traffic control centres.
The US government has been working to modernise the ageing technology used by air traffic controllers since Congress approved $12.5 billion for the project last year. Miles of old copper wires have been replaced with fibre-optic lines, while outdated radio systems are gradually being replaced at airports across the country.
However, significant work remains. Duffy has said another $30 billion would be required to complete the upgrades, and the White House has begun urging Congress to approve the additional funding.
The disruption appeared similar to a communications outage at a regional air traffic control centre in September that affected hundreds of flights across the northeastern US, aviation safety expert Steve Arroyo said. The latest incident, however, affected the country on a nationwide scale.
It may be linked to the ageing technology used by air traffic controllers, he said.
“If you don't have that ability, whether it's because the old wires that they have are just run down or for whatever reason, you've got to stop airplanes on the ground,” said Arroyo, a former United Airlines pilot. “And not put them in the air where you're going to risk not being able to communicate with them.”
Friday's ground stop differed from the one imposed after September 11, as planes were not instructed to land immediately. Pilots were also likely able to maintain communication with ground controllers at airports, Arroyo said.