A whistle-blower lawsuit claims Boeing Co. installed faulty parts in hundreds of 737 jetliners and attempted to hide the problem from regulators.
Boeing denied the employee allegations, first reported by The Washington Post on Monday. Boeing insisted no faulty parts slipped past its quality controls and that its planes are safe.
"Evaluation of this claim by Boeing and responsible government authorities supports our position that these claims are without merit," the company said in a statement.
The Federal Aviation Administration said it investigated the complaint and found that Boeing used approved parts and that the government's review of aircraft maintenance documents have turned up nothing to indicate that the parts were critical to safety or have led to any problems.
The Justice Department also declined to join the case on behalf of the whistle-blowers, who alleged Boeing had violated federal law by installing some of the parts in question on planes that were sold to the U.S. military.
The whistle-blowers all had been employed at Boeing's manufacturing facility in Wichita, Kansas. One of the whistle-blowers also made wrongful termination and sex discrimination claims against Boeing.
The suit alleges Boeing allowed thousands of parts to be installed on aircraft though the company knew they did not meet specifications. Assembly workers, in some cases, drilled holes in aluminum ribs used to construct the plane's skeleton because premade holes were misaligned.
The parts at issue were manufactured between 1994 and 2002 by Boeing supplier AHF Ducommun of Los Angeles, which was named in the lawsuit with Boeing.
The suit says Boeing concealed the problems from the FAA, sold the planes, and also retaliated against people who raised questions with management.
U.S. District Judge Wesley Brown in Wichita concluded in late February that key allegations in the suit were not specific enough to move forward but allowed the whistle-blowers to amend their filing, which they did in March. Boeing said it would move to throw out the revised case on April 24.
Boeing said it has a strong policy against retaliation and "we do not believe there is any basis" for that assertion in the complaint.
The Post said it had reviewed the FAA's probe and found the agency's investigative process was incomplete, and that regulators failed to inspect any airplanes containing the 200 types of parts questioned by the whistle-blowers.
An FAA spokeswoman said inspecting the suspect parts would require the difficult and time-consuming steps of taking out much of an aircraft's interior and wiring. Instead the FAA reviewed maintenance records, including those of planes that underwent the most extensive structural checks, and found nothing wrong.
The FAA also said the parts involved were not crucial for airworthiness.