Residual Flight Delays Expected Sunday From Critical FAA Warning System Outage

More than 500 flight delays were reported Sunday morning following the outage.

A plane takes off from Reagan National Airport after the crash last night of an American Airlines plane on the Potomac River as it approached the airport in Arlington, Va., on Jan. 30, 2025. Al Drago/Getty Images

Flights throughout the United States could experience “residual delays” Sunday morning while the Federal Aviation Administration (FAA) works to restore a critical warning system that faced an outage the night before, Secretary of Transportation Sean Duffy said on Feb. 1.

“The primary NOTAM system is experiencing a temporary outage, but there is currently no impact to the National Airspace System because a backup system is in place,” Duffy wrote in a post on social media platform X, adding that the FAA has activated a contingency system to “supplement and support preflight briefings and continue flight operations.”

“The [FAA] is working to fully restore the system, and there may be some residual delays tomorrow morning,” he said. “We are investigating the root cause, and we will provide updates.”

As of 8:30 a.m. ET Sunday morning, there were more than 540 delays within, into, or out of the United States, according to flight tracker FlightAware.

Notice to Air Missions (NOTAM) is a computer system that sends pilots alerts about conditions that could affect flight safety. These include information about inoperable runway lights, airport tower safety lights not working, or air shows taking place in nearby air space.

The alerts also notify pilots about potential bad weather on routes, runway and taxiway changes at airports, and closed airspace that must be avoided. The notices were established in 1947, inspired by a system used to warn ship captains of sea hazards. In the years since, the formerly paper-based system has evolved into a digital warning system.

While separate from the air traffic control systems that keep planes at safe distances from one another, NOTAM is another critical tool for air safety.

A previous outage of the system in January 2023 briefly halted all flights in the United States. The outage led to a massive air traffic jam following more than 1,300 flight cancellations and roughly 9,000 flight delays. The FAA said in the early stages of the outage that it believed a damaged database file led to the problem.

After an Air Canada jet almost landed on four other planes waiting to take off from San Francisco International Airport in 2017, the National Transportation Safety Board, which investigates aviation accidents, criticized the way the alerts are presented.

The Associated Press contributed to this report.