The mechanic, Richard Cuevas, worked for a firm that was hired by Boeing supplier Spirit AeroSystems to repair Boeing planes and was fired in March after raising concerns with both Spirit and Boeing, according to his lawyers.
The lawyers, Debra Katz and Lisa Banks, accused Spirit of “routinely cutting corners" on the work on pressure bulkheads and accused Boeing of allowing “shoddy work" to continue.
Boeing said it “thoroughly investigated” the claims.
“Engineering analysis determined that the issues raised did not present a safety concern and were addressed,” Boeing said in a statement.
The company said it is reviewing documents the man filed with federal agencies "and will thoroughly investigate any new claim. We are not involved in personnel decisions of subcontractors."
Spirit AeroSystems management “is aware of the allegations and looking into the matter. We encourage all Spirit employees with concerns to come forward, safe in knowing they will be protected," company spokesperson Joe Buccino said.
The mechanic's lawyers said he filed whistleblower complaints with the Federal Aviation Administration and the Labor Department.