The Federal Aviation Administration says contractors “unintentionally deleted files” while working on a live database and backup of its key pilot-notification system, prompting the unusual outage that grounded planes nationwide last week.
The FAA statement on its preliminary review sheds more light on the failure of the Notice to Air Missions system that warns pilots of potential hazards.
“The agency has so far found no evidence of a cyber-attack or malicious intent,” the agency said. “The FAA continues to investigate the circumstances surrounding the outage.”
The NOTAM failure early Jan. 11 was a major embarrassment to the FAA and led to the first nationwide ground stop since the aftermath of the Sept.