A nearly five-hour US aviation shutdown that disrupted more than 20,000 flights may have been triggered by a single router installed during routine maintenance by government contractor L3Harris.
The incident affected communications at 17 of the Federal Aviation Administration’s 22 en route centres, prompting a nationwide ground stop when officials were unable to identify the cause of the instability.
Transportation Secretary Sean Duffy said engineers were investigating whether the problem resulted from user or installer error, or from a faulty router. Officials have indicated that equipment may have been involved at locations in Arkansas and Texas.
“This was an FAA system that didn’t meet the moment,” Mr Duffy said.
According to Mr Duffy, L3Harris had been switching telecommunications lines from ageing copper wire to fibre at least one remote site when the issue emerged. The new routers reportedly generated more than 1,000 connection attempts every four to five seconds, overwhelming other routers and disrupting the flow of data between aircraft and FAA facilities.
The FAA said communications had not completely failed and that its centres had not gone dark. Instead, the incident caused instability in the data systems used across the network.
US aviation shutdown highlights ageing air traffic system
L3Harris said it was supporting the FAA’s investigation into the conditions that led to the November 13 ground stop. The company said it had completed more than 70 per cent of the planned conversion from legacy copper-wire communications to fibre optics.
The routers being replaced are about 25 years old and were originally due to be replaced in 2006. The FAA spends about US$1 billion each year maintaining its ageing copper-wire system while attempting to move to fibre-based communications.
Mr Duffy said the authority and its contractors needed to improve the work, noting that “virtually every single institution in America has gone from copper to fibre, from analog to digital”.
The disruption came as a surge in travellers began weekend journeys. It follows other failures in the FAA’s communications network, including a 2023 nationwide ground stop lasting 90 minutes after a government contractor accidentally deleted files.
Government officials have warned that further failures are possible until the system is properly upgraded. Congress has provided US$12.5 billion for improvements to the country’s ageing air traffic control and telecommunications infrastructure, while Mr Duffy has requested a further US$50 billion for air traffic control and airports.
