(CNN) The government is accusing United Airlines of flying an unsafe plane. The FAA wants to fine United for purportedly operating an airplane that was “not in air-worthy condition.” United mechanics replaced a fuel pump pressure switch on one of the carrier’s Boeing 747 jetliners back in 2014. The FAA claims the airline did not complete a required inspection of the repair before the plane resumed flying. It says United flew the aircraft on 23 domestic and international passenger flights before the inspection was performed.Two flights, the FAA says, happened after the it notified united about the problem. United said in a statement it “immediately took action after identifying the issue..and are working closely with the FAA in their review.” The FAA is proposing a 435-thousand dollar fine against the airline.