BBC: Flights grounded at major US airports after cable cut by construction workers

The Government Accountability Office (GAO) says that Federal Aviation Authority's (FAA) air traffic and communications systems are "vulnerable to cyber threats", including spectrum interference, spoofing and jamming which the report said could disrupt communications between aircrafts and ground control.

It adds that the FAA "hasn't sufficiently addressed" the threats, laying out several issues including a lack of real-time monitoring and detection software and a failure to complete risk assessments.

The FAA has not stated that a cyber attack is the cause of the ongoing disruption. US media are currently citing an issue with "frequencies" at Philadelphia air traffic control.

US Transportation Secretary Sean Duffy and aviation administrator Bryan Bedford just briefly spoke to reporters after an unrelated event.

Bedford confirmed that the malfunction was related to the Terminal Radar Approach Control System, which guides planes during takeoff and landing. He added that a "circuit failed", which then led to the discovery of a backup fibre circuit which had been damaged by construction crews in New Jersey.

He said that to repair the backup cable would take around 13 hours.

"It's massive, I'm told," Bedford said.

He added that the cut fibre line is around 600ft (183m) long, and that it was inadvertently damaged during "construction".

"Somebody dug it up," Bedford says.

Fixing the issue requires turning everything off - "sanitising the airspace" - and making sure that all flights are safe. So far, around 90 flights have been diverted to other regions, he estimated, saying he didn't know about the number of total cancellations.

Duffy added that these problems "are not new to us" and called on Congress to provide more cash to update the system.

Jeff