Southwest Airlines got in big trouble for flying a broken plane. The FAA hit the airline with a $325,000 civil penalty for operating a plane with a minor maintenance issue on more than 1,000 flights.

According to the Business Insider, the maintenance personnel for Southwest incorrectly installed a switch that lets flight crews test the windshield heater on an AirTran Boeing 717 in April 2011. Since Southwest is merging with AirTran, it must face the penalty for the mistake.

The FAA released a press notice about the issue saying, "Proper installation of the switch would have allowed personnel to isolate the windshield anti-ice system that was causing a warning that the windshield heater was failing. Instead, the center and left windshield warning systems were reversed.

The right windshield warning system continued to operate properly. The aircraft was operated on 1,140 passenger flights before the problem was corrected."

Southwest released a statement about the issue saying it is "actively working with the FAA on a resolution," and the "installation error did not result in a Safety of flight issue," since the primary notification system continued to work. The change was made after the aircraft was delivered, as a safety enhancement.

Southwest says the problem was fixed immediately after the plane was delivered.