US officials have found no evidence that hackers caused the outage that led the Federal Aviation Administration (FAA) to halt flight departures nationwide on Friday, and the FBI is reportedly examining whether a software update was responsible.
The FAA issued the ground stop on November 13 after a communications problem hit its air route traffic control centers. The order was lifted at 8:15 pm ET, more than four hours later, after disrupting thousands of flights. Departures have since resumed, though officials expect delays to continue for several days.
Homeland Security Secretary Markwayne Mullin told reporters at the White House that the incident did not appear to be the result of a cyberattack, and that the failure appeared to be mechanical.
On the absence of attack indicators, Mullin said “there’s no chatter, we haven’t seen any footprints.”
He stopped short of dismissing the possibility entirely. “However, we’re still looking, so we’re not going to rule that out,” Mullin said.
The NSA, the Department of Defense, CISA and other agencies have been involved in the investigation, according to Mullin.
The FBI does not think a cyberattack or criminal activity was behind the outage, Bloomberg reported, citing a person familiar with the matter. Investigators are looking at a software update as a potential cause, the source said.
Transportation Secretary Sean Duffy blamed legacy equipment. He said switches and routers in the FAA’s network were flooded with data and began producing inconsistent information, at which point the agency shut the system down.
Officials described the ground stop as a precaution.
Mullin offered a possible trigger. He said it appeared the FAA had been applying patches and installing new equipment and technology, which “was overwhelming the older system.”
CBS News, citing multiple sources, reported that the outage followed an update to the private communications network that links the air traffic control system. The network rebooted and then crashed, and it is operated by L3Harris, according to the report.
Officials said the incident had nothing to do with the Microsoft outage earlier in the week. They also said the FAA’s recently deployed AI systems played no role.
No official root cause has been announced.
The previous nationwide ground stop came in January 2023, after a contractor unintentionally deleted files while working on the system that delivers safety notices to pilots. No evidence of a cyberattack was found in that case either.
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