The workers were attempting to “correct synchronization” between “the live primary database and a backup database” when the outage occurred, the agency said Thursday.
The FAA said that there was no evidence of a cyber-attack or “malicious intent.”
More than 9,000 flights were delayed and nearly 3,000 were canceled on Jan. 11 due to the outage, which was discovered at around 7:30 a.m., causing a severe inconvenience for travelers waiting to board for departure.
“The FAA made the necessary repairs to the system and has taken steps to make the NOTAM (Notice to Air Missions) system more resilient,” according to the federal agency.
The airline issued several public apologies and provided refunds and flight credits to disgruntled passengers — many of whom were separated from their luggage and were forced to rent cars for long-distance trips due to the unavailability of air travel.