Local newspaper Rogue Valley Times published images of the missing panel.

Boeing said, also via email, that it would defer comment to United about the carrier’s fleet and operations. Its message included a link to information about the airplane that was involved, and it was said to be more than 25 years old.

There have been several incidents involving Boeing aircraft in recent months.

In January, a panel that plugged a space left for an extra emergency door blew off a Max 9 jet in midair just minutes after an Alaska Airlines flight took off from Portland, leaving a gaping hole and forcing pilots to make an emergency landing. There were no serious injuries.

The door plug was eventually found in the backyard of a high school physics teacher in south-west Portland, along with other debris from the flight scattered nearby. The Department of Justice has launched a criminal investigation.

On March 6, fumes detected in the cabin of a Boeing 737-800 Alaska Airlines flight destined for Phoenix caused pilots to head back to the Portland airport.

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The Port of Portland said passengers and crew noticed the fumes, and the flight landed safely. Seven people, including passengers and crew, requested medical evaluations, but no one was hospitalised, officials said.

Boeing on Friday told airlines operating 787 Dreamliners to check flight deck switches after a sudden mid-air dive by a LATAM Airlines 787 plane left more than 50 people injured on Monday.

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

AP

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