FAA grounds flights in the US because of outage

Some flights were allowed to resume by the Federal Aviation Administration (FAA) after an earlier outage of the system that alerts pilots to any obstructions before take-off had forced the civil aviation regulator to ground all aircraft in the United States.
As of early Wednesday morning, over 4,000 flights had been delayed and more than 600 canceled because of the outage. As a ground stop was lifted, U.S. flights were slowly beginning to resume departures.
This is a brief summary of the pilot warning system, what we know about what went wrong, and background information about the safety notices provided to pilots, known as NOTAM.
What happened?
About 2 a.m. Eastern Time, the FAA system that is meant to distribute notices to pilots on hazards failed, officials said.
The FAA ordered a halt on all domestic departures for airlines until 9 a.m. Eastern time while it tested whether crews had managed to restore the system and bring it back online.
U.S. President Joe Biden had been briefed on the outage by Secretary of Transportation Pete Buttigieg, according to the White House. “At this point, there is no evidence of a cyberattack,” White House Press Secretary Karine Jean-Pierre said in a tweet. She said that the U.S. Department of Transportation is conducting an investigation.
A NOTAM is a notice to airmen that contains information about potential hazards along a flight route or at a specific location that could affect the safety of the flight.
A system known as Notices to Airmen, which failed on Wednesday, is nearly a century old and was originally modeled after a system for notices to mariners.
In 2021, the system was changed to be called “Notices to Air Missions” and is meant to alert pilots to hazards, such as snow, volcanic ash or birds near an airport.
Provides information on closed runways and temporary air restrictions.
The United Nations’ aviation agency manages a global safety system that the U.S. Federal Aviation Administration’s NOTAMs are a part of.
Before take-off, pilots are required to review the notices, either printed on paper or on an iPad.
Long-haul international flights can have up to 200 pages of information.
Originally, NOTAMs were written in an encoded shorthand to make communication more efficient.
IN WHAT WAYS HAS THE SYSTEM CHANGED?
The ICAO has been leading an effort to overhaul the system to make it easier for airlines and pilots to filter the most important warnings and present them in clearer language.
In July 2017, an Air Canada jet landed on the wrong runway at San Francisco’s airport and came within seconds of colliding with four other planes.
The closure of one of the two runways at the airport had been flagged in the pre-flight NOTAM – on page eight of a 27-page briefing – and missed by the pilots.
Pilots complain that the incident and the information overload that the system encourages prompted the effort to change the way the system operates.
“Nobody pays any attention to (NOTAMs),” said U.S. National Transportation Safety Board Chairman Robert Sumwalt at a 2018 hearing on the Air Canada incident. This incident helped spur a global campaign for change.
Efforts to modernize the system have involved FAA officials in recent years.