The key facts
- More than 5,000 flights delayed and 2,000 canceled on Sunday; the day before — over 5,900 cancellations and 7,000 delays
- According to Sean Duffy, the failure was caused by a router that 'flooded' the network during the switch from copper lines to fiber optics
- Trump urged Congress to allocate funds for modernization, calling the system outdated
What happened
On Friday, the US Federal Aviation Administration (FAA) at 15:54 Eastern time announced a suspension of all departures from American airports until further notice. More than 3,500 aircraft were in the air at that moment: some were diverted to other airports, some reached their destinations. The stoppage lasted about four and a half hours, but its effects were felt throughout the weekend.
Scale of the consequences
On Sunday, according to FlightAware, more than 5,000 flights were delayed and about 2,000 were canceled. On Saturday, over 5,900 flights were canceled and more than 7,000 delayed. The failure also affected schedules outside the US: some flights from the UK and Europe were canceled. Passengers were stuck aboard planes on taxiways, spent the night in airports, and could not reach the airlines.
Cause of the failure
Transportation Secretary Sean Duffy said flights were halted after failures in a key communications system between controllers and pilots. According to him, a computer router installed in El Dorado, Arkansas, as part of the transition from copper wires to fiber optics, began transmitting erroneous signals and 'flooded' the network. The investigation into the causes and identification of those responsible are ongoing. Duffy warned that problems will continue to occur until the air traffic control system undergoes a complete modernization: 'We must invest in a network that has been neglected for decades.'
Political reaction
President Donald Trump on Sunday urged Congress to allocate additional funds for modernizing the air traffic control system, noting that a significant portion of the current system is about 50 years old, and saying the work should be done 'all at once, not in pieces.' Aviation analyst Miles O'Brien, in a comment to the BBC, compared the American system to 'a house that is about to be declared condemned.'
Image source, Getty Images 
