Thousands of flights were canceled or delayed in the United States Wednesday following an hours-long nationwide grounding of departures due to an outage of a key computer system used by pilots.
The Federal Aviation Administration said normal operations were being restored, but the early morning halt created knock on effects that were expected to snarl travel throughout the day.
“Normal air traffic operations are resuming gradually across the US,” the Federal Aviation Administration said on Twitter. “The ground stop has been lifted. We continue to look into the cause of the initial problem.”
The agency had identified an issue with the Notice to Air Missions system (NOTAM), which provides information to flight crews about hazards, changes to airport facilities and information that can affect flights.
But the outage was creating yet another hellish day for US travelers less than a month after a bad winter storm roiled the system.
“I just learned that my flight was delayed again,” Vince Hamilton said at Reagan National Airport near Washington of a planned trip to Chicago. “Then I go to St. Louis, and I have to catch a bus that I’m probably going to miss.”
Near 1900 GMT, some 1,200 flights in and out of the United States had been canceled, with more than 7,900 suffering delays, according to flight tracking website Flight Aware, which does not publish data on domestic flights alone.
The difficulties sparked fresh criticism on Capitol Hill and throughout Washington of the FAA, which has had no confirmed administrator since March.
– Cause unknown –
The FAA announced the problem on Twitter at 6:29 am eastern time (1129 GMT), saying it was working to restore the NOTAM system, announcing 50 minutes later that it ordered a pause on all domestic departures until 9:00 am.
Flying experts say the system contains a range of highly relevant details, such as a closed runway to less significant matters, like the presence of a crane somewhere in or near the airport.
About 30 minutes after the FAA lifted the stop order, a screen at Reagan National Airport was overwhelmingly red with flight delays and just a handful of departures.
“Customers may continue to see some delays and cancellations as we work to restore our schedule,” United Airlines said shortly after the FAA stop order was lifted, adding it would refund customers who no longer wished to travel.
