A critical Federal Aviation Administration computer system that crashed Wednesday, temporarily halting all U.S. flights, provides airlines with a digital bulletin board of critical safety updates.

This system is known as Notice to Air Mission or NOTAM. Send alerts to pilots to inform them of situations that may affect flight safety. This is separate from air traffic control systems that maintain safe distances between planes, but is another important tool for aviation safety.

A NOTAM message may contain information about lights that are off on a particular runway, towers near airports where the required safety lights are not working, or air shows taking place in nearby airspace.

“It’s like telling a truck driver that the road ahead is closed to traffic,” said Mike Boyd, an aviation consultant at Boyd Group International. “This is important information.” .

After the computer outage, flight disruption spreads across the United States. Follow live updates.

Although many flights do not need to see these notifications, it is important that pilots who are trained to see NOTAM messages receive them.

The FAA also operates the country’s air traffic control system, with air traffic controllers using radar to track all planes in the airspace and radio communications with the cockpit to guide them safely. . It is also known that the computer system that is the backbone of the control system will go down. But when it does, it usually only affects her one region of the country, not the entire country’s airspace.

FAA suspension — A video board shows flight delays and cancellations at Ronald Reagan Washington National Airport in Arlington, Virginia, on Wednesday, January 11, 2023.

AP Photo/Patrick Semansky

NOTAM is a national system, so Wednesday’s failure meant that flights across the country were ordered not to take off for several hours before being allowed to fly again just before 9 a.m. ET. I meant

If no new problems arise, flights should return to normal soon, but it may take some time to get all the delayed flights back into service. As of 9:30 a.m., the tracking service FlightAware shows his 4,600 delayed flights to, from and within the US, with 827 flights completely cancelled. Aviation analytics firm Circium said there were 23,000 domestic and international flights scheduled to and from the US on Wednesday.

“By 6pm today, you won’t even know it happened,” Boyd said.

But if the problem persists, crew waiting for delayed flights will run out of time in the workday. In that case, the delayed flight may be canceled if another new crew member cannot be found.

NOTAMS has been around for decades. However, until December 2021, it was known under the name “Notice to Airmen”, although the acronym remained the same as today.

Modified to remove gender terms. This was because notifications were sent not only to the pilot of the aircraft, but also to the drone operator.