The millions of dollars in fines that the government imposes against airlines for violating maintenance and repair regulations illustrate how serious and widespread problems are. They also point up how many flights — thousands, in some instances — take off when they shouldn’t and possibly endanger passengers’ lives.

The Federal Aviation Administration (FAA), which oversees airlines, levied $28.2 million in fines and proposed fines against 25 U.S. passenger airlines for maintenance violations that occurred during the past six years.

- The biggest was $7.5 million last March against Southwest. The airline operated 46 Boeing 737 jets on 59,791 flights in 2006 and 2007 without mandatory fuselage inspections for fatigue cracking. Six planes had cracks, the FAA says. After Southwest became aware it hadn’t made the inspections, the airline continued to operate the 46 planes on an additional 1,451 flights.

Southwest agreed to pay the fine and work with the FAA “on a number of actions to improve our ability to demonstrate compliance” with the agency’s requirements, says Beth Harbin, the airline’s spokeswoman. Southwest has “an enviable safety record,” she says.

- The FAA proposed a $5.4 million fine against US Airways in October.

During the past two years, the airline flew a Boeing 757 on 505 flights without required inspections on engine work and an Airbus A320 on 855 flights without the jet meeting the requirements for an engine repair, the FAA says. After the FAA pointed out the engine-repair concerns, US Airways continued to operate the A320 on 51 flights, the agency says.

In addition, the airline flew an Embraer 190 jet on 19 flights in October 2008 without complying with a safety directive requiring inspections to prevent a cargo door from opening in-flight, the FAA says.

US Airways spokeswoman Valerie Wunder says the airline is “working with the FAA toward a resolution” and won’t comment further.

About 90% of maintenance violations don’t result in fines but warning letters or other reprimands by the FAA, according to USA TODAY’s analysis of violations that occurred after Dec. 31, 2003, and were finalized as of June 23, 2009.

Combining warning letters, other reprimands and fines during that period, as well as subsequent fines and proposed fines through September 2009, airlines were cited for 1,300 infractions. American had the most — 226 — followed by Northwest, 167, and Alaska, 134. Southwest, which last year carried more passengers than any other U.S. airline, was cited for 92 infractions.

Such maintenance violations will continue until more severe sanctions than the current system of fines are imposed on airlines who violate FAA regulations, says John King, a whistle-blower and former airline mechanic who cited many problems at now-defunct Eastern Airlines.

Former National Transportation Safety Board member John Goglia says the FAA should put the money it collects into improving airlines’ maintenance training and programs.

The FAA says that money, by law, must go into the government’s general fund.

By Gary Stoller, USA TODAY