A 73-year-old passenger is dead and dozens were injured after a Boeing 777-300 en route to Singapore from London hit heavy turbulence and plummeted 1,800 meters in just three minutes before making an emergency landing in Bangkok.

While Boeing planes have been involved in numerous accidents caused by manufacturing defects in the recent past, there has been no evidence that the company is to blame in this case.

Singapore Airlines noted that the majority of the 211 passengers were from Australia, the United Kingdom, and Singapore, with the remainder coming from 14 other nations.

"Flight SQ321 encountered sudden extreme turbulence over the Irrawaddy basin," the airline said in a statement. "The pilot declared a medical emergency and diverted the aircraft to Bangkok.

They offered their "deepest condolences to the family of the deceased," adding, "We deeply apologise for the traumatic experience that our passengers and crew members suffered on this flight."

As the Guardian reports, seven people are in critical condition, and 23 are being treated for less serious injuries.

In a statement to Reuters, 28-year-old passenger Dzafran Azmir explained that, "very suddenly there was a very dramatic drop so everyone seated and not wearing a seatbelt was launched immediately into the ceiling."

"Some people hit their heads on the baggage cabins overhead and dented it," he said. "They hit the places where lights and masks are and broke straight through it."