FAA: Contractors Accidentally Deleted Files, Grounding All Flights

Files that were accidentally deleted led to an outage that prompted the FAA to order a ground stop on flights last week—halting departures and causing a ripple effect that led to thousands of delays and hundreds of cancellations, the agency said Thursday.

"Contract personnel unintentionally deleted files while working to correct synchronization between the live primary database and a backup database," the FAA said in a statement, adding that it has not found evidence of a cyber attack or malicious intent but the investigation is ongoing.

The agency added in the statement that it made the necessary repairs to its Notice to Air Missions system, which provides safety information to flight crews, and "has taken steps to make the NOTAM system more resilient."

"A Notice to Air Missions alerts pilots about closed runways, equipment outages, and other potential hazards along a flight route or at a location that could affect the flight," the agency explained in a previous statement.

Addressing widespread fears that the outage means that a key system keeping passengers safe is vulnerable, Secretary of Transportation Pete Buttigieg told CNN last week that he believes the question is "a real one."

"What are the redundancies, what are the backups, what are the means to make sure that a disruption like this does not happen ... We need to design a system that does not have those kinds of vulnerabilities," Buttigieg said on CNN.

The system shut down late Jan. 10, and overnight the FAA ordered a ground stop on all domestic flight departures. By 9 a.m. the following day, the system was restored and flights began to resume, though according to NPR, a total of 1,300 flights were canceled and nearly 10,000 were delayed as a result.