The FAA is investigating the way Southwest Airlines calculates luggage weight on its airplanes.
According to the Wall Street Journal, it's part of a civil probe that started a year ago.
FAA documents reveal that Southwest employee errors caused "widespread" baggage weight miscalculations, which led to pilots tallying the wrong weight of the aircraft at takeoff.
The media outlet reports that in some cases, those mistakes caused the recorded takeoff weight to be 1,000 lbs. less than than what the plane actually weighed.
Safety guidelines from the FAA state that additional weight on an airplane can lead to issues with takeoff and cruising speeds, maneuverability and landing gear.
Southwest's problem seems to lie in its process for counting bags. It's reportedly one of the only major U.S. airlines that doesn't utilize computers to calculate the total weight, instead relying on ground crew to count bags as they're loaded into the aircraft.
The FAA said it hasn't found any accidents related to the discrepancies. Citing unnamed sources, the Wall Street Journal reports that the agency hasn't decided whether or not it'll fine or punish the airline for the mistakes.
Southwest says it'll have a new, computerized baggage-counting process in place by the end of the year.
Additional reporting from Newsy affiliate CNN.