(LONDON) —  One person is dead and dozens others injured after a Singapore Airlines flight encountered “severe” turbulence, the airline said in a social media post.

The Boeing 777-300ER departed London’s Heathrow Airport on Monday with 221 passengers and 18 crew members on board, according the airline.

The flight, SQ 321, encountered turbulence about 90 minutes from its destination of Singapore and was diverted to Bangkok, the carrier said.

A 73-year-old man from Great Britain was killed, according to Kittipong Kittikachorn, general manager for Bangkok’s Suvarnabhumi Airport.

Seven people were critically injured, Kittikachorn added, while dozens suffered minor or moderate injuries.

“Suddenly the aircraft starts tilting up and there was shaking so I started bracing for what was happening, and very suddenly there was a very dramatic drop so everyone seated and not wearing a seatbelt was launched immediately into the ceiling,” Dzafran Azmir, a 28-year-old student on the flight, told ABC News. “Some people hit their heads on the baggage cabins overhead and dented it; they hit the places where lights and masks are and broke straight through it.”

Singapore Airlines confirmed one person had died and sent condolences to the family.

“Singapore Airlines offers its deepest condolences to the family of the deceased,” the airline said in a statement on Tuesday. “Our priority is to provide all possible assistance to all passengers and crew on board the aircraft.”

The aircraft appeared to have encountered the turbulence in Thai airspace, somewhere over the Andaman Sea.

The flight, which had been scheduled to arrive at Singapore Changi Airport, instead touched down in Thailand at about 3:45 p.m. local time, the carrier said.

“We are in contact with Singapore Airlines regarding flight SQ321 and stand ready to support them,” Boeing said in a statement. “We extend our deepest condolences to the family who lost a loved one, and our thoughts are with the passengers and crew.”

ABC News’ Joe Simonetti, Will Gretsky and Helena Skinner contributed to this report.

Copyright © 2024, ABC Audio. All rights reserved.