The man who had flagged concerns about Boeing’s safety standards has been found dead in his truck in the US.
John Barnett was a former employee who was giving evidence against the aircraft manufacturing giant in a lawsuit in South Carolina days before his death.
The 62-year-old was found with a “self-inflicted” wound on March 9, the Charleston County coroner told the BBC.
Police are investigating the circumstances surrounding his death, with his attorney Brian Knowles casting doubts about how his client died in an interview with TMZ.
Boeing said: “We are saddened by Mr. Barnett's passing, and our thoughts are with his family and friends.”
Mr Barnett worked for Boeing for more than three decades until he retired in 2017.
Two years later, he went on to tell the BBC that he was worried about the production standards at the firm.
He alleged that workers were under pressure and intentionally fitting sub-standard parts.
One issue he raised was about planes’ oxygen systems, as he believed that up to one in four breathing masks would not work in an emergency.
Boeing has denied the allegations, insisting that it follows strict safety protocols.
The company is currently under intense scrutiny, after a cabin exit door was town from a brand-new Boeing 737 Max in early January.
Several passengers sustained minor injuries but were treated by paramedics and did not require hospital treatment.
A preliminary report from the US National Transportation Safety Board said four key bolts which were supposed to hold the door in place had not been used.
The US Federal Aviation Administration (FAA) grounded Boeing 737 MAX 9 planes after the incident.
Boeing President and CEO Dave Calhoun said after the preliminary findings: “Whatever final conclusions are reached, Boeing is accountable for what happened. An event like this must not happen on an airplane that leaves our factory."
