The airspace over London was briefly closed Friday afternoon due to what authorities said was a computer failure at one of Britain’s two air traffic control centers.
NATS, Britain’s national air traffic body, said a computer problem at its center in Swanwick, England, had touched off troubles in the system but that was fixed and the agency was in the process of returning to normal operations. Officials at London Heathrow Airport blamed the failures on a power outage.
“We apologize for any delays and the inconvenience this may have caused,” NATS said in a statement.
The shutdown came at the start of the weekend in a sprawling city with five commercial airports, including London Heathrow – Europe’s busiest – as well as Gatwick, Luton, Stansted and London City Airports.
Heathrow alone handles about 1,200 to 1,400 flights a day, about 200 of those to and from the United States, according to the flight tracking service FlightAware. As of 11 a.m. ET (1400 GMT), FlightAware was noticing some delays at Heathrow but few cancellations.
“The problem is mostly impacting departures at this point. It is late afternoon in the U.K. and the majority of US-bound flights depart in the morning,” said Daniel Baker of FlightAware.
The Swanwick center has been plagued by problems since it opened more than a decade ago. It only swung into operation in 2002 – six years after its planned commissioning date and double its original budget. Software and reliability issues have caused repeated disruption since.
Last December, a computer problem at Swanwick took 12 hours to fix.
At Heathrow, passengers on United flight 941 to Newark were told about the computer problem as they boarded at 1530 GMT (10:30 am EST).United gate staff said the plane would be loaded with passengers and head toward a runway in the hopes that the computer problem could be fixed.
Most passengers at Heathrow seemed unaware of the issue and no further mention was made during normal boarding.
A Heathrow statement said “flights are currently experiencing delays and we will update passengers as soon as we have more information.”