Three Australians are receiving critical care in a Bangkok hospital after a London-to-Singapore flight suffered extreme turbulence this week.

From the 211 passengers and 18 crew, more than 50 Australians sustained injuries after the plane suddenly dropped at 37,000 feet. 71 people with injuries were treated at Samitivej Srinakarin Hospital in Bangkok. Hospital officials say that they have performed surgery on more than 10 patients.

A 73-year-old British man died on the flight, likely due to a heart attack.

Singaporean Prime Minister Lawrence Wong expressed his condolences and said that there would be a “thorough investigation”.

“I also hope and pray that those who are injured will recover and return home soon,” he said.

One Adelaide man who was on board the flight said that his wife “wasn’t in a good way”, currently recovering in Samitivej Srinakarin Hospital. He said that she was standing up when the plane suddenly dropped.

The first plane carrying passengers from the Singapore Airlines flight arrived at Sydney Airport on Wednesday afternoon.

Flight SQ321 experienced “severe turbulence” over Myanmar, resulting in an emergency landing in Thailand on Tuesday morning local time.

CEO of Singapore Airlines Goh Choon Phong apologised to the passengers of the flight.

“We are very sorry for the traumatic experience that everyone onboard SQ321 went through”, he said,

Singapore Airlines said that 131 passengers and 12 crew have since been flown to Singapore on a relief flight.

Photo: Singapore Airlines by Kentaro IEMOTO is available HERE and is used under a Creative Commons Licence. This image has not been modified.