Boeing has had numerous safety issues with its planes, including two fatal crashes in the past six years on its MAX jet and more recently the loss of an aircraft part midflight in January. Now, a former employee-turned-whistleblower at the company has been found dead.

The movement of a flight deck seat is a key focus of the probe into a sudden midair dive by a LATAM Airlines Boeing 787 plane that left more than 50 people injured, aviation industry publication the Air Current reported on Wednesday.

Former Boeing quality control manager, John Barnett, a whistleblower who went public with his concerns over safety issues in the company's commercial airplanes, was found dead outside a hotel in South Carolina.

The 62-year-old's death came after his recent testimony about safety issues within Boeing's aircraft production processes. His absence from a critical deposition against the company on Saturday prompted authorities to search for him at the hotel.

Meanwhile, the LATAM plane, which was heading from Sydney to Auckland on Monday, dropped abruptly before stabilizing, causing those on board to be thrown about the cabin.

Based on the available information, it was understood the seat movement was "pilot induced, not intentionally", the report said, citing a senior airline safety official.

"The seat movement caused the nose down" angle of the aircraft, the publication said, citing another anonymous source, who said the possibility of an electrical short was also under review.

Boeing is expected to release a message to 787 operators regarding the incident, the Air Current reported, in a sign a fleetwide issue could be involved, though it said the specific topic was not known to the publication.

Whistleblower Barnett spent decades working for Boeing, first at its plants in Everett, Washington, and beginning in 2010 as a quality control manager in North Charleston, South Carolina, NPR reported. He had spent years speaking out against what he alleged were shoddy manufacturing practices at Boeing, from which he retired in 2017.

Boeing's production practices have been questioned both on the 787, a model called the Dreamliner, and the company's best-selling plane, the 737 MAX.

Deadly accidents

MAX jets first went into service in 2017. In October 2018, a MAX 8 jet flown by Indonesian carrier Lion Air crashed into the Java Sea during a routine flight from Jakarta to Pangkal Pinang, killing all 189 passengers and crew.

In March 2019, another MAX 8 jet, flown by Ethiopian Airlines, crashed a few minutes after it took off, killing 157 passengers and crew. Investigations showed that both accidents were caused by design flaws, in particular flight-control software.

The company recently came under additional scrutiny this week after a six-week Federal Aviation Administration audit of Boeing and subcontractor Spirit AeroSystems found that the company routinely failed to comply with quality-control mandates.

The update came after a Boeing 737 MAX 9 lost a door plug midflight during an Alaska Airlines flight in January. After the incident, the FAA grounded all Boeing 737 MAX 9 planes with a door plug for investigation and inspected all the relevant aircraft.

Airline executives are frustrated with Boeing as its safety crisis has upended their business plans, Reuters reported.

United Airlines CEO Scott Kirby flew to France to talk with Airbus as Boeing's latest crisis erupted, looking to leverage Boeing's delays to secure better terms.

Boeing's delivery schedule faces extended delays following a Jan 5 midflight cabin blowout that exposed problems with safety and quality control in its manufacturing processes.

Kirby has been among the ones who have been expressing frustrations with Boeing.

Several weeks ago, American Airlines CEO Robert Isom blasted Boeing for its persistent quality issues, asking the jet manufacturer to get its act together. Last week, it placed its first-ever order for MAX 10 jets to secure an alternative to its Airbus A321 planes.