Boeing had denied John Barnett's accusations (File)
John Barnett, a former Boeing employee who flagged the safety concerns at the aircraft manufacturing giant, was found dead on Saturday.
South Carolina's Charleston County coroner confirmed Barnett's death to the BBC on Monday.
Who was John Barnett?
John Barnett worked for the US aerospace giant Boeing for more than three decades, until his retirement. The 62-year-old retired in 2017, on health grounds. After retiring, Barnett embarked on a long-running legal action against the firm.
Days before his death, Barnett had been giving evidence in a whistleblower lawsuit against the company. He worked as a quality manager at the North Charleston plant making the 787 Dreamliner from 2010. It must be noted that the 787 Dreamliner is a state-of-the-art airliner used mainly on long-haul routes.
What John Barnett Revealed
Back in 2019, Barnett in a conversation with the BBC revealed that faulty parts were deliberately fitted to planes by a line of production workers at one of the Boeing factories.
He uncovered some serious problems with the oxygen systems, which could even mean that one in four breathing masks wouldn't work during an emergency.
Barnett reportedly claimed that passengers on its 787 Dreamliner could be left without oxygen when the cabin suffered a sudden decompression.
Referring to a few tests, Barnett said that a quarter of the oxygen systems could be faulty and might not work when needed.
After a test on emergency oxygen systems, Barnett found that the 787 Dreamliner showed a failure rate of 25 per cent.
He said that in a bid to get a new aircraft built the assembly process in South Carolina was rushed, leading to compromised safety.
Not only this but the workers also failed to keep track of components in the factory, allowing the defective components to go missing.
He even accused the firm of using sub-standard parts from the scrap bins and fitting it to the planes, in a bid to prevent delays on the production line.
While he informed the managers about his concerns, no actions were taken. However, in 2017, a review by the Federal Aviation Administration (FAA), the US regulator, did uphold some of Barnett's concerns.
How Boeing responded to these accusations
Denying Barnett's accusations, Boeing said that all its aircraft were built to the highest levels of safety and quality. The company insisted that "safety, quality and integrity are at the core of Boeing's values".