‍DALLAS — Alaska Airlines (AS) has resumed operations early this morning after temporarily grounding its fleet due to an IT outage.

Last night, the Seattle-based carrier requested to the Federal Aviation Administration (FAA) a temporary, system-wide ground stop for AS and Horizon Air (QX) flights “until the issue is resolved." 

We have heard that the outage hit the airline’s Aircraft Communications Addressing and Reporting System (ACARS), and contacted the airline to corroborate whether the outage involved this IT system.

ACARS is a digital data link technology utilized for airline operations and air traffic control communication between aircraft and ground stations. A recent event at Newark Liberty International Airport (EWR) exemplifies the impact of an ACARS outage, resulting in ground pauses, flight delays, and cancellations.

Some online discussions have also mentioned issues with weight and balance data not coming through correctly or being inaccurate. A similar situation occurred on January 26, 2023, which resulted in two tail strikes in Seattle. That day coincided with the final Q400 revenue flights for QX.

Three hours ago, the airline took to X to say that it had resolved the IT outage and resumed operations, adding, "We sincerely apologize for the inconvenience, and encourage guests to check your flight status before heading to the airport.”

Last night's outage comes day after Microsoft issued a security update warning, issuing an alert about "active attacks" against server software used by companies to transmit internal documents. However, no link has been established between the Microsoft warning and the AS system outage.

For now, the disruption and restart of AS's operations mean the airline’s regular flight schedule will take some time to come back to normal.

UPDATE

Alaska Airlines responded our inquiry with the following:

"We’re working to get our operations back on track today at Alaska Airlines and Horizon Air after a significant IT outage Sunday night resulted in a system-wide ground stop of flights, which was lifted at 11 p.m. Pacific.

A critical piece of multi-redundant hardware at our data centers, manufactured by a third-party, experienced an unexpected failure. When that happened, it impacted several of our key systems that enable us to run various operations, necessitating the implementation of a ground stop to keep aircraft in position. The safety of our flights was never compromised.

Since Sunday evening, we’ve had more than 150 flight cancellations, including 64 cancellations today. Additional flight disruptions are likely as we reposition aircraft and crews throughout our network.

The IT outage is not related to any other current events, and it’s not connected to the recent cybersecurity incident at Hawaiian Airlines [HA].

We are currently working with our vendor to replace the hardware equipment at the data center."