What's behind the latest air travel chaos? Problems with the little-known NOTAM system

Hundreds of flights were delayed or cancelledacross the U.S. early Wednesday, spotlighting the importance of a little-known, and critics say antiquated, computer system that generates pre-flight alerts for pilots and other aviation staff.

TheNotice to Air Missions (NOTAM)system provides pilots and flight crew with a host of key safetyinformation.From weather conditions on route, to airspace closures and potential problems at airports, pilots need the latest data from the system in orderto fly, said John Pottinger, president of Pottinger Aviation Safety, a Canadian consultancy firm.

"It's a notice of everything you are going to need to know before you make a flight," he told CBC Newson Wednesday of theNOTAMsystem, which iscommunicated to pilots digitally. "Are these systems reliable enough and secure enough?If it even goes down for an hour or two, you can see what happens."

More than 1,200 flights in the U.S. had been cancelled by 4 p.m. ET Wednesday, according to FlightAware, a tracking website. More than 8,700 flights were delayed following problems with the U.S. NOTAM system, which also resulted in anumber of Canadian flights to and from the U.S. beingdisrupted Tuesday and Wednesday.

The FAA reported that the NOTAM system failed around 3:30 p.m. ET Tuesday, meaning no new messages about up-to-date weather or airport conditions could be processed. The grounding of many flights in the U.S. was lifted around 9 a.m. ET on Wednesday.

Problems with the NOTAM systemin the U.S., and the ensuing flight cancellations, have raised questions about how it's designed and whether the underlying digital infrastructureused to communicate information to aviators is up to the job.

WATCH | Aviation safety expert explains computer system problems:

Aviation safety expert explains NOTAM system outages

1 year ago

Duration 7:36

John Pottinger, the president of Pottinger Aviation Safety, talks about what may have contributed to the computer outages in the United States and Canada that resulted in thousands of delays and hundreds of cancellations.

When was NOTAM created and how does it work?

According to the U.S.Federal Aviation Administration (FAA), theNOTAMsystem wasfirst established in 1947.

NOTAMsmust be provided to the pilots of any plane, big or small, private or commercial, before takeoff, Pottinger said.

Decades ago, the latest information was communicated to flight crews in person before departure.The system then became telephone based, and pilots would receive a call with updates on conditions.

In the last three to four years, the NOTAM system wasdigitized following guidance from the UN's International Civil Aviation Organization (ICAO),Pottinger said, and most updates are sent online.

These digital systems aren't as robust as they should be in many places including the U.S., the aviation consultant said, as evidenced by Wednesday's outage.

"If they fail, that means you are going to have significant delays."

Airports and air traffic control regulators and organizationssuch as the FAA and NAV Canada, createthe notices that are sent to the system.

An airport might include information such as updates about a closed runway or lighting problems, Pottinger said. Air traffic regulators provide information on issues likeairspace closures or weather hazards enroute.

This information is made available to pilots, airline staff and others in the industry ahead of a flight.

What caused the problem?

Officials with the FAA haven't said what specifically went wrong with the NOTAM system. ButU.S. officials said they don't believe the outage was related to a cyberattack.

U.S. President Joe Biden said he has directed the Department of Transportation to investigate the outage.

Transportation Secretary Pete Buttigiegtold CNN that there would be ripple effects from the morning's delays.

"Now we have to understand how this could have happened in the first place. Why the usual redundancies that would stop it from being that disruptive did not stop it from being disruptive this time."

WasCanada affected?

NAV Canada, the organization responsible for air traffic control in this country, reported an outage for new updates to the NOTAM system for a couple of hours mid-morning Wednesday, but said the problem didn't cause any flight delays.

In Canada, pilots were still able to readNOTAMs,but there was an outage that meant new notices couldn't be entered into thesystem, NAV Canada said on social media.

When new information couldn't be added to the platform, Pottinger believes Canadian air traffic controlofficials may have reverted back to phone calls to communicate the latest datato pilots.

NAVCanada said it did not believe theoutage was related to the one in the U.S., but it said it was investigating.

What happens next?

Problems with the NOTAM system did not put passenger safety at risk, Pottinger said, but the outagedid cause major headaches for travellers and airlines.

Some of the digital "background architecture" underpinning the NOTAM system"is pretty old in the U.S. and Canada," he said, noting thattechnology glitches likelycontributed to the problem.

Travel industry officials calledon the government to improve the system.

"America's transportation network desperately needssignificant upgrades," Geoff Freeman, president of the U.S.Travel Association, said in a statement. "We call on federalpolicymakers to modernize our vital air travel infrastructure."