Independence Air could be fined as much as $1.5 million because the government says it flew thousands of flights last fall without conducting scheduled maintenance and inspections on some planes.
The Federal Aviation Administration said Thursday that it's proposing the penalty because the airline missed the deadline to perform inspections and tests on a variety of systems and components.
For example, Independence Air failed to do heavy maintenance and inspections that were required on a regional jet, and then flew the plane for 455 more flights before performing the work.
All the flights cited by the FAA were normal and passengers weren't affected in any way, the airline said in a statement.
Independence Air also said the problems resulted when it upgraded its record-keeping system and found errors in the way it scheduled its maintenance checks. The airline said it voluntarily disclosed the problems to the FAA, and both the agency and the airline say they've been corrected.
"We have been working closely with the FAA since that time and have long ago resolved these issues and their underlying cause," the statement said.
Formerly Atlantic Coast Airline, Independence Air Inc. is struggling to transform itself into a low-fare carrier. Industry analysts believe it may have to file for bankruptcy protection.
The airline flies to 45 destinations on 400 daily flights, mostly from its hub at Washington's Dulles International Airport.
The airline has 30 days to respond to the FAA. It said it expects the final fine will be lower than the proposed amount, which often happens.