FILE PHOTO: A Southwest Airlines Co. Boeing 737 MAX 8 aircraft taxis after landing at Midway International Airport in Chicago, Illinois, U.S., March 13, 2019. REUTERS/Kamil Kraczynski

CHICAGO (Reuters) - The U.S. Federal Aviation Administration (FAA) said on Friday it is seeking to impose a $3.92 million fine on Southwest Airlines Co LUV.N for alleged weight infractions on 21,505 flights on 44 aircraft between May 1, 2018 and Aug. 9, 2018.

The FAA alleged that Southwest operated the flights with incorrect operational empty weights, and center of gravity or moment data, which is used to determine how many passengers and how much fuel can be safely carried and where cargo should be located.