Boeing 787 Dreamliners are built at the aviation company's North Charleston, South Carolina, assembly plant on May 30, 2023.JULIETTE MICHEL/AFP via Getty ImagesAnother whistleblower has come forward with complaints of Boeing's safety lapses.Richard Cuevas said that he saw holes drilled improperly, which could lead to "catastrophe."The airplane mechanic said he was fired from his job shortly after raising concerns.