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The Federal Aviation Administration is resuming domestic flight departures after it reported a technology outage reported overnight.
The FAA's system for alerting pilots and airports of real-time hazards, called NOTAM (Notice to Air Missions), went dark around3:28 a.m. ET.
"THE FAA is experiencing an outage that is impacting the update of NOTAMS. All flights are unable to be released at this time," the FAA said in an advisory announcing the issue.
More than 4,314 flights had been delayed within, into or out of the United States when the pause was lifted. Another 700 had been cancelled.
The FAA had opened a hotline to address equipment issues by 5:58 a.m. ET, as some NOTAM functions began to come back on line.
Airports and airlines nationwide were warning on Twitter before the ground stop that delays would be expected.
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Attention #PHLAirport passengers- an FAA outage is impacting flights across the country. Check with your airline regarding your flight status. https://t.co/VNSa99NJt6
— PHLAirport (@PHLAirport) January 11, 2023