(Dallas, TX) — Federal regulators are investigating Southwest Airlines after the Dallas based carrier failed to accurately track the combined weight of checked bags loaded onto Southwest jetliners.

The Wall Street Journal reports the Federal Aviation Administration has spent a year looking into Southwest.  The FAA found what it called systemic and significant mistakes in calculations and how bags are loaded.  That’s led to potential discrepancies when pilots compute takeoff weights.

The FAA hasn’t decided whether it will fine Southwest or impose some other punishment.