WASHINGTON (CNN) -- Southwest Airlines will pay $7.5 million to settle complaints that it flew unsafe aircraft, and the fine will double unless the airline completes additional safety measures within a year, federal regulators announced Monday.

The FAA found Southwest operated jets on nearly 60,000 flights without performing certain mandatory inspections.

The Federal Aviation Administration originally recommended more than $10 million in civil penalties in 2008 after finding Southwest operated 46 of its Boeing 737 jets on nearly 60,000 flights without performing mandatory inspections for fatigue cracks in their fuselages.

FAA documents obtained by CNN found that in some cases, Southwest aircraft flew for 30 months after government inspection deadlines had passed.

A congressional panel concluded the planes were "not airworthy," and two FAA whistle-blowers said agency managers let the airline conduct the safety checks on a slower schedule to avoid disrupting flights.

The Dallas, Texas-based airline said it was happy to have settled "all outstanding issues with the FAA."

"This settlement with the FAA will allow us to focus on safety going forward, rather than on issues that are now behind us and that have already been addressed," Southwest Airlines said in a written statement.

CNN's Mike M. Ahlers contributed to this report.
Who was happy to settle? What flew for 30 months after inspection deadlines passed? How much will the fine increase if the airline doesn't complete additional safety measures? What was the airline fined? Amount of planes FAA found that Southwest flew without checking? What airline flew nearly 50 planes without inspecting for cracks? Who flew 46 jets without checking for fatigue? Which agency fined Southwest for flying jets without checking for cracks? How long did Southwest fly affected aircraft after the inspection deadlines?
Southwest Airlines Southwest Airlines double $7.5 million 46 Southwest Southwest Airlines FAA 30 months
question: Who was happy to settle?, answer: Southwest Airlines | question: What flew for 30 months after inspection deadlines passed?, answer: Southwest Airlines | question: How much will the fine increase if the airline doesn't complete additional safety measures?, answer: double | question: What was the airline fined?, answer: $7.5 million | question: Amount of planes FAA found that Southwest flew without checking?, answer: 46 | question: What airline flew nearly 50 planes without inspecting for cracks?, answer: Southwest | question: Who flew 46 jets without checking for fatigue?, answer: Southwest Airlines | question: Which agency fined Southwest for flying jets without checking for cracks?, answer: FAA | question: How long did Southwest fly affected aircraft after the inspection deadlines?, answer: 30 months