More than 10,000 flights have now been delayed or canceled by the first national grounding of flights since the 9/11 attacks—and authorities are still trying to determine the cause of the system outage that led to the grounding. Transportation Secretary Pete Buttigieg tells CNN that there's no evidence of a cyberattack at this point. "There's been no direct evidence or indication of that but we are also not going rule that out until we have a clear and better understanding of what's taken place," he says. Buttigieg says the Federal Aviation Administration is still looking for "the original source of the errors or corrupted files" that caused a 90-minute halt to departing flights.
The outage hit the Notice to Air Missions System, which pilots are required to consult to learn about potential hazards along flight routes. Flight were halted from 7:30am to 9am Eastern. According to an FAA bulletin, problems with the system began Tuesday afternoon. FlightAware said Wednesday evening that 9,400 flights had been delayed so far and over 1,300 canceled, and the numbers were still rising, reports Reuters. Major airlines including American, Delta, and Southwest said that at least 40% of flights had been affected but that they were hoping to get things back to normal by Thursday.
Buttigieg says the halt was ordered to be "absolutely sure, out of an abundance of caution, that no aircraft could take off without the necessary safety information." He says his main priority is finding out why the outage happened—and why backup systems were unable to prevent massive disruption. "With a government system, we’re going to own it, we're going to find it, and we're going to fix it," he says. Republicans including Sen. Ted Cruz slammed the "dysfunction" at the FAA and promised to make changes, the Washington Post reports. Rep. Sam Graves, the new chairman of the House Transportation Committee, said lawmakers should be briefed on what went wrong. (Read more Federal Aviation Administration stories.)