DALLAS (AP) — Until Wednesday, few travelers had ever heard of a Notice to Air Missions, or NOTAM, nor did they know that the system used to generate those notices could cause widespread travel misery.
As they arrived at airports in the morning, they quickly found out.
The Federal Aviation Administration computer system that compiles and distributes essential safety information for pilots went kaput. That temporarily grounded all flights nationwide and touched off a cascading air traffic jam that will take at least a day to unclog. More than 1,300 flights were canceled and 9,000 delayed by early evening on the East Coast because of the outage, according to flight-tracking website FlightAware.
The system has been around for more than a half century and it has evolved from paper to computers. It’s in the process of being updated.
WHAT ARE NOTAMs?
They are compilations of essential preflight information for pilots, airline dispatchers and others that include details about things such as potential bad weather on the route, runway and taxiway changes at airports and closed airspace that must be avoided. The notices began in 1947 and were modeled after a system used to warn ship captains of hazards on the seas.
A pilot can’t legally take off until he or she has reviewed the information. John Hansman, an aeronautics professor at MIT, said most airlines subscribe to services that gather NOTAM information from the FAA and package it for each flight. Airline dispatch centers relay it to pilots. In this case, the services couldn’t get the information because the FAA system malfunctioned, he said.
WHAT WENT WRONG WITH THE SYSTEM?
The FAA said preliminary indications “traced the outage to a damaged database file.” The agency said it would take steps to avoid another similar disruption.
The system stopped working at 8:28 p.m. Eastern time on Tuesday, but because there weren’t many departures at that hour, pilots were able to get the information verbally. At daybreak in the East, the system was still out, and there were too many flights leaving to brief pilots individually.
It’s likely that the main system had a problem, and the backup didn’t work correctly. The FAA rebooted the main system around 5 a.m., but it took a while to verify that all the information was validated and available, Transportation Secretary Pete Buttigieg said. So the FAA ordered all flights grounded Wednesday morning and planes were stuck for hours “to make absolutely sure the messages were moving correctly and the information for safety purposes is working the way it should,” Buttigieg said.
Longtime aviation insiders could not recall a systemwide FAA outage of this magnitude caused by a technology breakdown.
HOW IS THE GOVERNMENT RESPONDING?
Buttigieg said that the NOTAM system is constantly being updated, and a key question is whether it’s outdated.