Aviation regulators in the United States have ordered airlines to carry out inspections of hundreds of Boeing 787 Dreamliners after a sudden midair dive during a flight in March injured dozens of passengers.

The Federal Aviation Administration (FAA) said on Monday that the captain’s and first officer’s seats on certain 787-7, 787-9 and 787-10 aeroplanes should be inspected “for missing or cracked rocker switch caps and for cracked or nonfunctional switch cover assemblies” within 30 days.

“Operators must also perform any necessary corrective actions,” the FAA said in a statement.

The FAA directive affects 158 US-registered aeroplanes and 737 aeroplanes worldwide, the regulator said.

The airworthiness directive (AD) comes after Chile’s aviation authority said earlier this year that preliminary inquiries into the March 11 incident showed that the captain’s seat experienced an “involuntary movement forward” during the flight.

Some 50 passengers were injured when LATAM Flight 800 suddenly plunged 400 feet (120 metres) while en route to Auckland, New Zealand from Sydney, Australia.

In its directive, the FAA said the “uncommanded horizontal movement” of the captain’s and first officer’s seats during LATAM Flight 800 had “caused the control column input to disconnect the auto-pilot, resulting in a rapid descent until the First Officer took control of the flight”.

The FAA received four additional reports of the problem from Boeing following the incident, the most recent of which was in June, the regulator said.

“Uncommanded horizontal movement of an occupied seat can cause in-flight upset from unintended and abrupt flight control inputs, which could result in a rapid descent of the airplane and serious injury to passengers and crew,” the FAA said.

“The FAA is issuing this AD to address the unsafe condition on these products.”

Boeing said in a statement that it fully supports the directive, “which makes mandatory a supplier’s guidance to 787 operators.”

The directive is the latest in a series of incidents to draw attention to safety issues at Boeing.

Boeing last month finalised a deal to plead guilty to fraud after US prosecutors concluded that the company violated a deferred prosecution agreement over two fatal crashes of the 737 Max jetliner in 2018 and 2019.

The Arlington, Virginia-based aircraft giant is also facing a separate criminal investigation into a January incident during which a 737 MAX operated by Alaska Airlines lost part of its fuselage mid-flight. (Al Jazeera)

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