A former senior manager at Boeing’s 737 plant in Seattle has raised new concerns over the safety of the company’s 737 Max.

The aircraft, which was grounded after two accidents in which 346 people died, has already been cleared to resume flights in North America and Brazil, and is expected to gain approval in Europe this week.

But in a new report, Ed Pierson claims that further investigation of electrical issues and production quality problems at the 737 factory is badly needed.

Regulators in the US and Europe insist their reviews have been thorough, and that the 737 Max aircraft is now safe.

In his report, Mr Pierson claims that regulators and investigators have largely ignored factors, which he believes, may have played a direct role in the accidents.

He explicitly links them to conditions at the company’s factory in Renton, near Seattle at the time. Boeing says this is unfounded.

MCAS problems

Lion Air flight JT610 crashed into the sea off Indonesia in October 2018. Five months later, Ethiopian Airlines flight ET302 came down minutes after take-off from the Ethiopian capital Addis Ababa.

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Investigators believe both accidents were triggered by the failure of a single sensor. It sent inaccurate data to a piece of flight control software, called MCAS.

This automated system then repeatedly forced the nose of the aircraft downwards, when the pilots were trying to gain height. Ultimately each aircraft was pushed into an unrecoverable dive.