US flight chaos: Thousands stranded as FAA halts take-offs nationwide – what we know so far

Air travel across the United States was thrown into disruption on Friday after the Federal Aviation Administration (FAA) ordered a nationwide halt to flight departures, citing a telecommunications outage affecting regional air traffic control centres.The unprecedented move grounded flights at airports across the country and disrupted travel plans for thousands of passengers, including people heading home, attending weddings and travelling for weekend events.

The FAA said the restriction was imposed “due to extraordinary circumstances and for reasons of safety”.The ground stop was the first nationwide suspension of flights since January 2023, when a key FAA computer system malfunctioned, and only the second such order since the September 11, 2001, attacks.Homeland security secretary Markwayne Mullin said the outage appeared to be a telecommunications problem and that officials had no indication it was the result of an attack.

However, the precise cause remained under investigation, with authorities examining the communications systems used by air traffic controllers.Here is what we know so far about the disruption, its possible cause and its impact on passengers.Why did the FAA ground flights across the US?The FAA ordered the nationwide ground stop after a communications problem affected the 22 regional air route traffic control centres responsible for directing aircraft travelling between airports.Transportation secretary Sean Duffy said FAA technicians were investigating the issue.

The agency described the decision as a safety measure, saying flights could not continue departing normally while the communications systems were affected.According to an airline source cited by CNN, the FAA told carriers that the outage was caused by a problem with network routers. The issue was believed to have originated at Chicago Midway International Airport before spreading across the country.The FAA was reportedly unable to provide a clear explanation of the problem during initial crisis discussions, with different facilities experiencing its effects in different ways.The ground stop meant aircraft could not take off, while planes already airborne were allowed to continue towards their destinations and land.

Officials said they were handling flights still in the air on a case-by-case basis.Is the outage linked to a cyberattack or security threat?US officials said there was no indication so far that the disruption was caused by a deliberate attack.Mullin told reporters at the White House that the problem was a telecommunications outage and not, based on the information available at the time, a hostile act against the country."There was no indication as of yet this was a nefarious attack against us," he said.He added that officials were still investigating what had caused the outage and cautioned against making assumptions before the findings were available.CNN, citing law enforcement sources, reported that preliminary assessments did not point to a cyberattack.

A senior US security source later told the broadcaster that multiple law enforcement and intelligence agencies, including the FBI, Department of Homeland Security and National Security Agency, were examining the incident.The investigation was continuing to examine how the government's aviation systems connect to networks that could potentially be exposed to malicious actors. The senior security source said there was still no indication of an attack.Mullin also said officials were not ruling out any possibilities at the early stage of the investigation.Are the problems linked to the new FAA AI system or Microsoft outage?Officials initially considered whether the FAA's nationwide rollout of a new artificial intelligence-supported system could have contributed to the disruption.The system, known as SMART, analyses flight schedules, weather forecasts and other data from a location near Washington, DC.

It then sends recommendations to the FAA's command centre and air traffic controllers.However, the system does not directly operate the regional air traffic control centres affected by Friday's communications outage.In a statement, ASI, the company that designed the system, said, "the current ground stop is not based on or a result of the SMART system, any product of ASI or our integration with FAA and ATC."Mullin said officials had no indication that the new system was responsible for the disruption.

He also said the outage was not connected to the major Microsoft services disruption reported earlier in the week.Microsoft separately said it had no indication that the FAA's nationwide ground stop was related to any of its services.How many flights have been affected?The disruption led to cancellations and delays at airports across the country, with further problems expected as the ground stop continued.According to aviation analytics company Cirium, nearly 481 flights had been cancelled or had failed to depart within 180 minutes of their scheduled departure time as of 4.40 pm Eastern time on Friday.

This represented around 1.8% of the 26,284 flights scheduled to depart from US airports that day.Most of the affected departures at that stage were from airports in New York, San Francisco and Boston. Cirium said around 11,000 flights were scheduled to depart after 4 pm Eastern time, raising the prospect of further cancellations.The number of affected journeys increased as the hours-long suspension continued, leaving airlines and passengers trying to rearrange travel plans.The FAA's ground stop order was in effect until at least 11 pm Eastern time on Friday, although officials did not provide a definite timeline for restoring normal operations.What are airlines telling passengers?Major US airlines warned customers to expect disruption and advised them to check flight information before travelling to airports.United Airlines said domestic flights would not depart during the suspension, while international departures were being handled by the FAA on a case-by…