The aircraft’s landing gear also remained deployed throughout the short flight, when on a 787 the wheels are normally withdrawn as soon as they leave the runway.

One possibility is that the landing gear became stuck and that the pilots responded by partially retracting the flaps to reduce drag and maintain the climb. If the adjustment was overdone, the plane would lose lift and begin to descend.

Questions had previously been raised about possible flaws in the construction of the 787.

‘Faulty engineering’

Sam Salehpour, a Boeing engineer, came forward in 2021 with claims that the firm had cut corners on the Dreamliner, allowing “faulty engineering and faulty evaluation of the data” which meant that defective parts had potentially been installed in some planes.

Mr Salehpour claimed to have noticed issues with the filling in of gaps between fuselage segments, known as shimming, which he said could cause fatigue cracks over repeated flights.

John Barnett, another whistleblower, alleged that Boeing repeatedly falsified or ignored vital quality checks at a plant in North Carolina where some of its 787s are assembled.

Mr Barnett – a quality inspector who was later found dead aged 62 – also warned of problems with emergency oxygen systems and his discovery of metal shavings that he said posed a risk of shorting to electrical systems.