A major power outage halted air traffic Sunday at Hartsfield-Jackson Atlanta International Airport, the world's busiest.
The FAA said in a statement that it ordered a ground stop for flights into the airport due to the impact of the outage on airport terminals. A ground stop means flights to the airport are held at departure airports across the nation. The FAA said departures also were delayed.
"The FAA tower can operate normally, however, departures are delayed because airport equipment in the terminals is not working," the statement said.
The flight-tracking website FlightAware said inbound flights were being held at thier departure airports until 4 pm. Flight delays out of the airport averaged 1 hour and 40 minutes, the website said.
Airport officials said the outage began just before 1 pm. Georgia Power said it was aware of the outage and was investigating.
U.S. Customs and Border Protection announced that international flights were being diverted to other airports.
Major airlines were canceling flights. Southwest Airlines was canceling "all but a handful of international flights," according to an airline spokesperson.
Delta Air Lines said it was aware of the power outage and the flight disruptions were expected. Delta customers were encouraged check the status of their flight via the Fly Delta Mobile App or Delta.com.
In 2016, the airport handled 104,171,935 passengers, the most of any airport in the world.