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The 2023 NOTAM Outage: What Caused the Last Nationwide Ground Stop

The Federal Aviation Administration halted takeoffs nationwide on Friday, Nov. 13, something it had not done in nearly four years. The previous nationwide stop, the 2023 NOTAM outage, had a cause the FAA eventually spelled out: contractors deleted files while trying to fix a database sync. Because headlines from that January morning are circulating again, this account separates what the FAA and congressional auditors confirmed about 2023 from what was only reported at the time.

Where it stands: The Associated Press described Friday’s order as “the first nationwide ground stop since January 2023 when a key FAA computer system malfunctioned.” As of late Friday afternoon, officials had not named a root cause for the new stop, and nothing below about 2023 should be read as an explanation for it. Our verification of what is confirmed about Friday’s ground stop tracks that separately.

What the 2023 NOTAM outage knocked out

NOTAM stands for Notice to Air Missions. The system distributes the bulletins pilots and dispatchers must check before departure: closed runways, construction cranes near a field, restricted airspace, navigation aids out of service. If new notices cannot be issued or read, crews cannot confirm a route is safe, which is why a database failure with no aircraft involved ended up holding flights at the gate.

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The Congressional Research Service noted at the time that the FAA’s own budget request had asked for “almost $30 million” toward modernizing the program that houses NOTAMs, and that Congress had funded it. The money was flowing; the replacement was not yet in service.

The timeline, hour by hour

Outlets did not agree on when the trouble began. CNBC reported that “the issues started around 3:30 p.m. ET on Tuesday,” Jan. 10. The Associated Press, citing FAA advisories, put the failure at 8:28 p.m. that evening, when new or amended notices stopped reaching pilots. One plausible reading is an afternoon degradation followed by an evening failure, but no official account we could read resolves it.

Overnight, the FAA fell back on a phone hotline. According to the AP, that worked while traffic was light and buckled once the morning rush began. Early on Wednesday, Jan. 11, the agency told airlines to hold all domestic departures until 9 a.m. Eastern. In the statement ABC News carried, the stated purpose was “to allow the agency to validate the integrity of flight and safety information.”

Departures restarted in stages. ABC reported Newark and Atlanta moving at about 8:15 a.m. and quoted officials announcing at about 8:50 a.m. that “the ground stop has been lifted.” NPR reported that by 9 a.m. ET the system was fully restored.

Moment (ET) What happened Source
Tue., ~3:30 p.m. Problems begin CNBC
Tue., 8:28 p.m. NOTAM system fails, per FAA advisories AP
Overnight Phone hotline used as a stopgap AP
Wed. morning Domestic departures paused until 9 a.m. ABC News
Wed., ~8:50 a.m. Officials say the stop is lifted ABC News
Thu. morning 636 delays, 82 cancellations AP / FlightAware

Cause: what the FAA said, and when

The explanation came in two steps. On the night of the outage and the day after, the FAA pointed to a damaged database file and said there was no evidence of a cyberattack. CNBC added a detail from a person familiar with the matter: “Both the primary and back-up systems were fed the corrupted data file.” That was single-sourced and never confirmed on the record.

About a week later the agency published its preliminary finding, quoted by Nextgov: “A preliminary FAA review of last week’s outage of the Notice to Air Missions (NOTAM) system determined that contract personnel unintentionally deleted files while working to correct synchronization between the live primary database and a backup database.” NPR reported that investigators had still found no sign of malicious intent.

That is the extent of the official record we could verify. Reports naming a specific contracting firm, and claims that the FAA adopted a particular staffing rule for maintenance work, come from pages we could not open and confirm, so they are left out here.

How big the disruption was

The totals shifted all day, which is why different numbers still circulate. More than 21,000 U.S. departures were on the schedule that Wednesday, according to Cirium data cited by the AP. CNBC’s tally from FlightAware, published the next day, was 10,563 delayed flights and more than 1,300 cancellations. The Government Accountability Office later rounded those to “almost 10,000” delays and “over 1,300” cancellations.

The duration figures differ in the same way. GAO wrote that the FAA grounded departures “for about 2 hours,” and Nextgov said the stop ran nearly two hours.

Aviation veterans quoted by the AP were blunt. Former pilot John Cox said, “I’ve been flying 53 years. I’ve never heard the system go down like this.” Tim Campbell, a former American Airlines operations executive, said many FAA systems “are old mainframe systems that are generally reliable, but they are out of date.”

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Recovery the next morning

By Thursday morning the schedule had largely snapped back. The AP counted 636 delays and 82 cancellations, and CNBC quoted the FAA saying it was seeing “no unusual delays or cancellations this morning.” Delays climbed again later that Thursday, though CNBC tied part of that to weather. GAO’s later summary adds a caveat that the quick headline recovery hides: “Some airlines took several days to fully recover.”

International traffic was less affected. The AP reported that European flights into the U.S. appeared largely unaffected, and that Aer Lingus and Lufthansa said their schedules held.

What the FAA changed after the outage

Immediately afterward, the agency said it had repaired the system and, according to NPR, taken steps to make it “more resilient,” without saying which.

The larger change was a review. GAO reports that after the NOTAM failure, the FAA ran an operational risk assessment covering every air traffic control system it operates. The result was stark: of 138 systems, 51 (37 percent) were rated unsustainable and 54 (39 percent) potentially unsustainable.

The NOTAM platform itself is being replaced. ExecutiveGov reported that the FAA picked CGI Federal in 2025 to build a cloud-based NOTAM Management Service, replacing infrastructure that dated back to 1985. In May 2026 the agency said the first phase was finished: the legacy U.S. NOTAM System was retired in April, and AVweb reported officials describing that as more than a year ahead of the earlier estimate. The second legacy platform, the Federal NOTAM Service, was still scheduled for retirement later in 2026.

Transportation Secretary Sean Duffy framed the switch politically, telling ExecutiveGov that “the last administration handed us a 40-year old aviation alert system on the verge of complete collapse.” That is his characterization. The CRS record shows Congress was already paying for NOTAM modernization in the 2022 and 2023 budgets, before the current administration took office.

Frequently Asked Questions

What caused the 2023 NOTAM outage?

The FAA said a preliminary review found that contract personnel unintentionally deleted files while correcting synchronization between the live primary NOTAM database and a backup database. The agency said it found no evidence of a cyberattack or malicious intent.

How long did the January 2023 ground stop last?

Accounts differ slightly. Nextgov put it at nearly two hours and GAO at about two hours. ABC News quoted officials saying the stop was lifted at about 8:50 a.m. ET on Jan. 11, with some hubs resuming earlier.

How many flights were delayed or canceled by the NOTAM failure?

CNBC, citing FlightAware, put the day at 10,563 delayed U.S. flights and more than 1,300 cancellations. Earlier same-day counts were lower because they were taken before the day ended.

Is Friday’s ground stop caused by the same problem?

No official has said so. The 2023 cause was specific to the NOTAM database. For Friday, the FAA and Transportation Secretary Sean Duffy have described communication issues at Air Route Traffic Control Centers and have not named a root cause.

Has the old NOTAM system been replaced?

Partly. The FAA chose CGI Federal in 2025 to build a cloud-based NOTAM Management Service. ExecutiveGov and AVweb reported in May 2026 that the first phase was complete and the legacy U.S. NOTAM System was retired, with the Federal NOTAM Service still to be shut down.

Sources


This article is news reporting and analysis based on the public sources listed above, as they stood on the dates shown. Where officials, lawmakers or analysts disagree, including on whether an action is lawful, their positions are attributed to them; News Accurate is not a court and nothing here is legal advice. Facts in a developing story can change.

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