The Federal Aviation Administration is investigating another Boeing whistleblower’s claims, The New York Times reported Tuesday. The former engineer at the aerospace giant, Sam Salehpour, claimed that Boeing’s 787 Dreamliner and 777 jets had structural issues that put their fuselages at risk of breaking apart mid-flight after repeated use. Salehpour charged that the large size of the components on Boeing’s planes—and the fact that each section is often made by different manufacturers—meant that they sometimes did not fit together exactly as they were supposed to, according to the Times. The longtime engineer, who worked at the company for more than 10 years, said he tried to raise his complaint through internal Boeing channels but was “threatened and silenced” by his former bosses, his lawyers said. He’s not the first former employee to come forward with safety concerns at Boeing in recent years. A quality control engineer named John Barnett, 62, was found dead last month just before a scheduled deposition in a whistleblower lawsuit against the company.