FAA says contractor unintentionally caused last week’s air-traffic outage

The Federal Aviation Administration said Thursday that a contractor working for the air-safety regulator had unintentionally deleted computer files used in a pilot-alert system, leading to an outage that disrupted U.S. air traffic last week.

The agency, which declined to identify the contractor, said its personnel were working to correctly synchronize two databases—a main one and a backup—used for the alert system when the files were unintentionally deleted.