The January 11 incident, which resulted in the cancellation of all flights in the United States, were employees of a contractor company that maintains the US Federal Aviation Administration (FAA) software platform.

The FAA Notice to Air Mission Systems (NOTAM) notification system was launched in 1993, 30 years ago, and will continue to operate for another six years. The program is responsible for sending critical information to pilots necessary for the flight. The cause of the failure was a corrupted file that caused both the primary and backup NOTAM systems to fail.

Now experts are investigating the incident, trying to identify the nature of the cause of the failure: a human factor or malicious intent. Eight employees of the contractor company had access to the system, and one or two of them made changes to the key file. U.S. Secretary of Transportation Pete Buttigieg asked the FAA to "ensure that the system has sufficient safeguards in place to ensure that failures of this level cannot be due to the decision, action or error of an individual." The incident is being investigated by order of the President of the United States.

On January 11 at 7:20 am ET, the FAA issued a notice directing airlines to suspend all domestic flights until 9:00 am. The work of NOTAM was restored at 8:50 - from that time air traffic began to gradually resume.