The Federal Aviation Administration lifted its nationwide halt of departing planes on Wednesday morning after a technology outage delayed thousands of flights, but airlines warned the issue will continue to disrupt travel throughout the day.
The FAA said early Wednesday domestic departures would be paused until at least 9 a.m. ET while the agency worked to restore the Notice to Air Missions System, which is responsible for sending messages to all pilots, such as closed runways, hazards and other information.
The FAA Notice to Air Missions (NOTAM) system is described in the Aeronautical Information Manual Chapter 5-1-3:
General. The NOTAM system provides pilots with time critical aeronautical information that is temporary, or information to be published on aeronautical charts at a later date, or information from another operational publication. The NOTAM is cancelled when the information in the NOTAM is published on the chart or when the temporary condition is returned to normal status. NOTAMs may be disseminated up to 7 days before the start of activity. Pilots can access NOTAM information online via NOTAM Search at: https://notams.aim.faa.gov/notamSearch/ or from an FSS.
Preflight. 14 CFR § 91.103, Preflight Action directs pilots to become familiar with all available information concerning a planned flight prior to departure, including NOTAMs. Pilots may change their flight plan based on available information. Current NOTAM information may affect:
Runways, taxiways, and ramp restrictions.
Status of navigational aids or radar service availability.
Other information essential to planned en route, terminal, or landing operations.
In other words, although aviation publications such as approach charts, taxiway diagrams, sectional and IFR charts, and supplements provide up to date information on changes such as those described above, but because they are updated only periodically, can't reflect late breaking scenarios. This is where the NOTAM system comes in. Per 91.103, pilots need to become familiar with all NOTAMs relevant to their flight prior to departure. If there is no system to disseminate these NOTAMs, this mandatory preflight action can't occur and the flight can't be conducted.
Imagine if your destination airport just had a crash on its only runway, and needed to close it. Without the NOTAM system, you'd have no way of knowing this had occurred.
Third party apps like ForeFlight disseminate NOTAMs compiled from the FAA system, but when that system doesn't function, they can't be sent out. Here is what ForeFlight itself is alerting its users today regarding NOTAMs: