The Federal Aviation Administration said Monday it is proposing a $325,000 fine against Southwest Airlines for flying an airplane too long after it had received temporary repairs. Monday’s penalty brings to $12,653,550 the total in proposed penalties that the FAA has levied against the Dallas airport over the past 20½ months, including a $12 million fine from 2014 that Southwest contested. Here’s the gist of the FAA’s allegation in Monday’s case: On July 9, 2014, an FAA inspector performed an aging aircraft inspection on the Boeing 737 while it was at a maintenance facility in San Salvador, El Salvador.