John Barnett died on Saturday from an apparently "self-inflicted" gunshot wound, a coroner in South Carolina confirmed to the BBC.

The 62-year-old was a quality manager for Boeing for 30 years before retiring in 2017.

The BBC, which first reported the news of Mr Barnett's death, said he had been giving evidence in a whistleblower lawsuit against the company in the days before his death.

In 2019, Mr Barnett told the BBC that up to a quarter of the oxygen systems could be faulty and might not work in an emergency.

He also claimed faulty parts were deliberately fitted to planes on one production line where the assembly process was rushed and safety was compromised.

Boeing denied both claims.

In a statement, Mr Barnett's family said his whistleblower complaint, filed in 2017, was due to go to trial in June.

"He was looking forward to having his day in court and hoped that it would force Boeing to change its culture.

"John carried all this on his shoulders to try to bring this all to light in the interest of the flying public."

The BBC reported that Mr Barnett had been due to face questioning from lawyers about his whistleblowing on Saturday but did not turn up.

When enquiries were made at his hotel, he was found dead in his vehicle in the hotel car park.

His lawyer told the BBC Mr Barnett's death was "tragic".

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His death comes as Boeing faces a series of safety-related events. On Monday, 50 people were injured when one of its aircraft suffered a "technical" issue mid-air.

In February, the head of US aviation regulator the Federal Aviation Authority (FAA) said the current safety system was "not working" and that the body was increasing its oversight of Boeing and reviewing its practice.

It followed an early January mid-flight blowout in which a door plug blew off a Boeing 737 MAX 9 Alaska Airlines aircraft.

MAX 9 planes across the US were grounded for around three weeks so emergency door panels could be urgently inspected and the company increased checks across all of its plants and suppliers.