On Wednesday, Jan 11, all domestic United States flights were grounded for the first time since 9/11. Flights that were already in the air were safe to land. 

   The Federal Aviation Administration (FAA) grounded all flights Wednesday morning after a Notice To all Air Missions (NTOAM), system failure. The NTOAM sends pilots important information needed to fly. 

   According to WBNS, the system went down late Tuesday but was not fixed until midday on Wednesday. 

   According to ABC, the system failure was due to a mistake that occurred during regularly scheduled maintenance. 

   According to NBC, an engineer accidentally replaced one file with another without notice of the mistake that was made. The corrupted file affected both the normal and backup systems.. 

   According to ABC, Canada’s NTOAM also experienced a disruption on Wednesday but the disruption did not cause them to ground flights due to their system backups. Their systems were able to return to normal function much quicker than the United States; however, it is unknown if the cause was linked to the US systems.

   Even after the flights were allowed to resume many passengers’ flights were canceled and delayed due to the accident. 

   According to WBNS, there were over 9,000 delays and 1,300 cancellations by Wednesday evening. Many passengers were upset about the confusion and annoyed that there was no time frame for how long the delays would last. 

   FAA engineers will now work to ensure that the outage does not happen again and that other systems won’t have similar problems.