The FAA grounded all Alaska Airlines flights in the U.S. on Wednesday morning for one hour. Delays are expected throughout the day.
The FAA posted an advisory on its website at 7:30 a.m. Pacific time stating, "All Alaska mainline and subcarrier flights are ground stopped."
The ground stop lasted until 8:30 a.m., causing dozens of flight delays, mainly at Seattle-Tacoma International Airport.
Alaska Airlines said it "experienced an issue while performing an upgrade to its system that calculates weight and balance."