The FAA outage was caused by a contractor’s mistake, US air safety officials say.
The Federal Aviation Administration said the contractor ‘unintentionally deleted files’ in the Notice to Air Missions (Notam) system.
The contractor was working on synchronising the primary and backup Notam databases.
The snafu led to over 11,000 flight delays across the country.
It caused the first national ground stop since 9/11.
The FAA said it ‘took steps to make the Notam system more resilient
