Shares in Boeing fell in pre-market trading on Monday after a door panel blew out of one of the US aircraft maker’s planes mid-flight, prompting several airlines to ground similar models.
The company’s stock price was down more than eight percent at around $228 a few hours before the New York Stock Exchange was due to open.
Boeing had closed on Friday up 1.66 percent at $249.
US authorities are investigating Friday’s incident in which a door plug fell off a Boeing 737 MAX 9 aircraft operated by Alaska Airlines over the northwestern state of Oregon.
The plane made an emergency landing but there were no major injuries among the 177 people on board.
The chief of the National Transportation Safety Board (NTSB) said Sunday a school teacher found the missing part in his backyard in the city of Portland.
The US Federal Aviation Administration (FAA) has ordered the grounding of 171 MAX 9 aircraft globally for inspection.
US-based Alaska and United Airlines fly the largest number of MAX 9 planes of any carrier and said on Sunday they had grounded their aircraft for inspection.
Other carriers with smaller MAX 9 fleets, including Turkish Airlines, said they did the same.
Boeing has struggled in recent years with technical and quality control issues related to its 737 MAX models.
Boeing’s 737 MAX planes were grounded worldwide following two MAX 8 crashes in 2018 and 2019 that killed 346 people in total.
The FAA approved the planes’ return to service only after the company made changes to its flight control system.
