WASHINGTON
A government investigator says federal regulators let Southwest Airlines Co. violate safety rules by operating planes that hadn't undergone required maintenance inspections.
The Office of Special Counsel faults the Federal Aviation Administration's oversight of Southwest, which continued to fly six Boeing 737 jets that didn't go through inspections of rivets around the window frames. The flights occurred in 2007.
The special counsel's office, which investigates whistleblower complaints by federal workers, said it sent a report of its findings to the White House and Congress.
The report echoed complaints raised by whistle-blowing FAA inspectors during congressional hearings in 2008. The inspectors said FAA managers ignored warnings about maintenance problems at Southwest and let the airline operate planes that hadn't undergone required inspections of their fuselages.
Southwest said Friday it has addressed the safety issues raised in the report and settled them when it agreed to pay a $7.5 million civil penalty last year.
According to documents released by the special counsel, Southwest told an FAA supervisor that the planes hadn't undergone required structural inspections. The supervisor failed to find out why Southwest missed the inspections or make sure that the airline caught up on the work.
A second FAA official violated agency policy by closing the case without reviewing the file or proposing penalties against Southwest, according to Transportation Department documents written in October and disclosed Thursday. The FAA is part of the Transportation Department.
Investigators said Southwest continued to fly six planes for two weeks after it knew the aircraft hadn't undergone the required inspections and after telling the FAA that it was complying with all safety regulations.
FAA spokesman Lynn Lunsford said the agency was reviewing the report. He said the agency had adopted measures to avoid a repeat of previous lapses, including preventing a single manager from making decisions about whether an airline can self-report problems. Airlines that voluntarily report problems can avoid punishment by the FAA in many cases.
The charges of lax oversight became public when an FAA inspector in Dallas, Charalambe "Bobby" Boutris, complained to the special counsel's office and later testified before Congress.
Southwest spokesman Brad Hawkins said the $7.5 million settlement with FAA in 2009 "has allowed us to focus on safety going forward, rather than on issues that are now behind us and that have already been addressed."
Hawkins said the safety issues raised in the new report were addressed in audits by the FAA, Southwest, and consultants hired by the airline. He said Southwest was "confident that we have identified and remedied the issues related to FAA inquiries" before 2009.