DALLAS (AP) - Southwest Airlines agreed to pay $2.8 million to settle a lawsuit by the federal government over maintenance on dozens of its planes.

DALLAS (AP) Southwest Airlines agreed to pay $2.8 million to settle a lawsuit by the federal government over maintenance on dozens of its planes.

The Justice Department said Monday that Southwest also agreed to pay up to $5.5 million in additional penalties if it fails to improve oversight of contractors it hires to perform maintenance work.

The Federal Aviation Administration sued Southwest in November 2014 in federal district court in Seattle.

The FAA charged that from 2006 to 2009 Southwest used 44 Boeing 737 planes that had undergone improper fuselage repairs and flew two planes in 2012 after making improper alterations of fluid-draining systems.

Southwest hired a contractor, Aviation Technical Services Inc. in Everett, Washington, to perform the work but was still responsible for making sure that it was done correctly, the FAA said.

According to Boeing instructions, when repairs are made to overlapping aluminum panels that make up a plane's fuselage, workers are to apply sealant between the panels and install new fasteners within a limited time. ATS workers placed fasteners in only some of the rivet holes during the allowed time, the FAA charged.

FAA Administrator Michael Huerta said the settlement give Southwest strong incentives to correct problems discovered by FAA investigators.

Southwest spokesman Brad Hawkins said that safety is the airline's top priority. "We remain committed to meeting or exceeding all applicable FAA safety regulations," he said.