(CNN) -- Southwest Airlines tried to keep serious problems with its maintenance program hidden and pressured the Federal Aviation Administration to keep out an inspector who noticed the problems, according to two FAA inspectors who blew the whistle on the airline.
Bobby Boutris and Douglas Peters told CNN Wednesday they brought information about Southwest's lack of compliance with mandatory inspection protocols to their supervisors, but the FAA did nothing.
Boutris said the airline tried to have him removed from the inspections.
"My supervisor called me into his office ... and told me he had had a meeting with the director of quality assurance and the AD [airworthiness directive] compliance leader from Southwest Airlines, and he had requested my removal from the inspection," Boutris said.
Linda Rutherford, Southwest's public relations vice president, wouldn't comment on the inspectors' allegations, noting that company Chairman Herb Kelleher and CEO Gary Kelly would be testifying Thursday before a House panel convened to look into the issue.
"Out of respect for the congressional hearing process, we will present testimony there, both oral and in writing, that addresses many of the questions being asked," she said. "Out of respect for the committee hearing process, we need to let those questions wait for the committee."
CNN was unable to reach the FAA for a comment Wednesday night, but earlier in the day, acting administrator Robert Sturgell would not discuss specifics of the Southwest matter.
"We had a breakdown in the system with Southwest Airlines. It was a two-way breakdown," Sturgell said, without elaborating.
Boutris and Peters, along with representatives from the FAA, are also scheduled to testify at Thursday's House Transportation and Infrastructure Committee, which conducted an investigation after the two inspectors brought forward their concerns.
Peters said he doubted anything would have changed if he and Boutris had not spoken up.
"Bobby and I were not happy with the state of Southwest Airlines' maintenance program," Peters told CNN Wednesday. "We weren't happy. And we saw the airline was at risk due to the lax oversight. And because of this, we just weren't willing to accept anything other than sweeping change." Watch Boutris ask: Why didn't FAA ground Southwest planes? »
In early March, CNN obtained documents from the House committee investigation that alleged the discount airline kept dozens of aircraft in the air without mandatory inspections -- and in some cases, with defects the inspections were designed to detect.
Boutris and Peters said FAA managers knew the Southwest planes were flying illegally and did nothing about it, according to the documents.
The inspectors wrote that Southwest, which carried more passengers in the United States last year than any other airline, flew at least 70 planes without a mandatory inspection on the rudder unit, part of the steering mechanism, some of them as much as 30 months beyond the mandatory rudder inspection.
The airline also flew at least 47 planes beyond a mandatory inspection of the fuselage, or skin, of the planes for possible cracks, the inspectors said. When the inspections were carried out, six of the planes were found to have possibly dangerous cracks, they said.
Speaking with CNN Wednesday, Boutris questioned why the airline did not immediately ground those 47 planes when they learned they were out of compliance.
"It is sad that an FAA inspector has to become a whistle blower in order to do his job," Boutris told CNN. "And the job is -- that we were hired by the taxpayers -- to ensure the airlines provide safe transportation for the flying public. It shouldn't have to come to this."
Boutris and Peters are seeking protection via the federal whistle blower protection program.
After the initial revelations, the FAA proposed a $10.2 million fine -- its biggest ever against an airline -- against Southwest for flying Boeing 737s without mandatory checks for fuselage cracking. Later, the agency ordered its inspectors to ensure airlines were complying with 10 airworthiness directives -- orders to check or correct a known unsafe condition -- and to expand the review to include more directives thereafter.
Sturgell, speaking at a news conference Wednesday, said the audit showed 99 percent compliance with federal airworthiness directives. There is room for improvement, said Sturgell, adding he is proposing several initiatives to strengthen the reporting role and regulatory process.
The new reporting system is to be in place by April 30, he said. E-mail to a friend