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.
The first thing about that plane is it has plenty of ventilation
That’s what makes it Covid-safe.
It’s like the old biplanes, the key is to fly to a max altitude of 75 ft. Going higher is just frivolous anyway.