AP EXPLAINS: How NOTAMs paralyzed flights in the US

Until Wednesday, few passengers had heard of NOTAMs (an acronym in English for Notice to Air Missions or Notice to Air Missions) and had no idea that the system that generates these alerts could cause so much hardship in air transport.

When they arrived at the airports in the morning, they understood quickly.

The Federal Aviation Administration (FAA) computer system that compiles and provides essential safety information to pilots has malfunctioned. This temporarily paralyzed all flights nationwide and caused air traffic congestion that will take at least a day to clear up. More than 1,300 flights were canceled and another 9,000 had been delayed overnight on the East Coast because of the problem, according to flight tracking website FlightAware.

The system has been in use for over half a century and has evolved from paper to computer. It is in the process of updating.

WHAT ARE NOTAMS?

The advisories compile essential pre-flight information for pilots, airline dispatchers and other personnel, and include details about things like possible bad weather en route, runway and taxiway changes at airports, and spacing. closed airways to be avoided. The notices began to be distributed in 1947 and were based on the system used to warn ship captains of dangers at sea.

Legally a pilot should not take off until he has reviewed the information. John Hansman, a professor of aeronautics at the Massachusetts Institute of Technology (MIT), said most airlines subscribe to services that compile the FAA information for NOTAMs and send it to each flight. The airlines’ flight dispatch centers forward them to their pilots. In this case, the services did not compile the information due to a malfunction in the FAA’s system, he added.

WHAT WAS THE PROBLEM?

The FAA said preliminary indications “trace the failure to a damaged database file.” The agency said it would take steps to prevent another similar outage.

The system went down Tuesday at 8:28 a.m. ET, but since there weren’t many sorties at that time, the pilots were able to receive the information verbally. At dawn on the East Coast, the system was still down and there were too many takeoffs to relay the information to individual pilots.

It is likely that the main system had a problem, and the backup system was not working correctly. The FAA restarted the main system around 5 a.m., but it took some time to verify that all the information was validated and available, Transportation Secretary Pete Buttigieg said. So the FAA ordered all flights to be grounded Wednesday morning and the planes were grounded for hours “to ensure that messages were flowing properly and information for security purposes was working properly,” Buttigieg said.

Longtime aviation associates do not recall an FAA system shutdown of this magnitude due to a glitch in technology.

HOW IS THE GOVERNMENT RESPONDING?

Buttigieg said the NOTAM system is constantly being updated, and a crucial question is whether it is outdated.

“We will not allow the use of anything unsafe,” Buttigieg told reporters. “This is precisely why our interest right now is to understand, identify, and correct anything related to the root cause of how it happened in the first place.”

US Representative Sam Graves said the NOTAM failure is inexcusable and a result of the Department of Transportation and the FAA “failing to properly maintain and operate the air traffic control system.”

Graves, chairman of the House Transportation Committee, said the FAA has been without a permanent director for nearly a year. He added that he awaits a full report on the outage.

WAS THERE ANY PROBLEM WITH THE SYSTEM BEFORE?

Not of this magnitude. “Periodically there have been local issues here or there, but this one is quite historically significant,” said Tim Campbell, a former senior vice president of air operations at American Airlines and now a consultant in Minneapolis. Although the cause of Tuesday’s outage was not immediately clear, Campbell said there were concerns about FAA technology, and not just the NOTAM system.

Other FAA technology is also becoming outdated, Campbell said. “A lot of their systems are old, generally reliable, but outdated computer systems,” he said.

The infrastructure law passed last year channeled $25 billion to airports, with roughly $5 billion going to air traffic control facilities. Legislative staff said that part of those resources could be used for equipment. But Buttigieg noted that any improvements to NOTAMs may have to wait for a new funding initiative for the FAA.

“I think this gives us an important information point and an important moment to understand what we will need to move forward,” he said.

The National Transportation Safety Board (NTSB) has criticized the way NOTAMs are presented after an Air Canada jet nearly landed on top of four planes waiting to take off at San Francisco International Airport in 2017. The pilots did not see the information about a closed runway that was among many other notices.

SHOULD THE GOVERNMENT COMPENSATE PASSENGERS?

Airlines will have to pay refunds and other compensation, even though the FAA was to blame for grounding flights. Kurt Ebenhoch, a consumer advocate and former airline executive, said passengers are entitled to a full refund if an airline cancels a flight for whatever reason.

Major airlines including Delta, American, Southwest and United were waiving flight change fees for flights on Wednesday, and in some cases on Thursday, to make it easier for passengers to change their travel plans.

The government is not legally required to refund passengers, which is maddening, said Brett Snyder, a travel agent and author of the travel blog “Cranky Flier.”

“Secretary Buttigieg should set the example and make direct refunds to the people from government coffers,” he said.

COULD IT HAPPEN AGAIN?

It is not clear. Congress was poised to examine aviation technology after Southwest Airlines crew scheduling problems during the holiday season led to the cancellation of nearly 17,000 flights in the last days of December. Now, the system that sends the NOTAMs and the supporting systems will be included in the inquiry.

“We will investigate what caused this outage and the importance of redundant systems in preventing such incidents from happening in the future,” Senate Transportation Committee Chair Senator Maria Cantwell said in a statement. “The public needs a strong air transportation system.”

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Krisher reported from Detroit and Koenig from Dallas. Associated Press writers Mike Pesoli and Eileen Putman in Washington and Frank Bajak in Boston contributed to this report.

This story was originally published on January 12, 2023 2:48 p.m.