John Barnett had worked for Boeing for 32 years, until his retirement in 2017.
In the days before his death, he had been giving evidence in a whistleblower lawsuit against the company.
Boeing said it was saddened to hear of Mr Barnett’s passing. The Charleston County coroner confirmed his death to the BBC on Monday.
It said the 62-year-old had died from a “self-inflicted” wound on 9 March and police were investigating.
I know this is a joke but you can’t buy a new 747 from Boeing even if you wanted to. Boeing stopped taking orders for the 747 in 2020 and the last plane rolled off the production line in 2022.
That’s why he’s never buying one again. He’s buying 737 MAXes now
The first thing about that plane is it has plenty of ventilation
That’s what makes it Covid-safe.