Australians return home after deadly plane turbulence

Australians have begun returning home from a fatal Singapore Airlines flight where passengers were thrown around the plane's cabin during a severe bout of turbulence.

The flight from London had 56 Australians on board when it was forced to make an emergency landing in Bangkok.

Relieved passengers returned to Sydney Airport on Wednesday night, with one woman describing the emotional toll of the ordeal.

"When it happened I was really calm. It wasn't until I got off the plane and sat in that room, since then I can't stop crying," Beverley Mayers told Nine News.

"My son has come to pick me up and I said to him 'I have to stay with you tonight and see my other children, and just hold them close'."

A relief flight arrives in Singapore
At least 30 passengers were injured due to the severe turbulence. (EPA PHOTO)

Speaking from Samitivej Srinakarin Hospital in Thailand with her arm in a sling, Teandra Tukhumen said she was flung from her seat before she could comply with the crew's seatbelt sign direction.

"I was asleep and then I was woken up because I was thrown to the roof and then the floor," she told Sky News UK.

"It was just so quick. They had no warning whatsoever.

"The pilot saved our lives. We're alive, so that's all that matters in the end."

A 73-year-old British man died of a suspected heart attack and 30 other passengers were injured when the plane hit severe turbulence 10 hours into the flight, flinging people around the cabin as the plane plunged about 6000 feet within minutes.

At least eight Australians were taken to hospital.

Australian and International Pilots Association safety and technical director Steve Cornell, who has flown the same type of aircraft involved in the incident, said the level of turbulence experienced was uncommon.

"There are three categories of turbulence: light, medium and severe ... severe turbulence is quite a rare occurrence," he told AAP.

"You frequently encounter light and moderate turbulence, but severe turbulence is very rare.

"There would be a lot less injuries if passengers did keep their seatbelts fastened at all times, regardless of if the seatbelt sign is off or on."

Home Affairs Minister Clare O'Neil said her thoughts were with those affected by the incident.

"This is a terrible experience that these people have gone through," she told Seven's Sunrise program.

"I know the embassy in Bangkok and the High Commission in Singapore are actively trying to contact those Australians ... we will do everything we can to help."

A Department of Foreign Affairs spokesman said officials were making further inquiries to determine if other Australians were affected.

Ambulances transport injured passengers to hospital in Bangkok
Eight Australians were among the passengers taken to hospital in Bangkok. (EPA PHOTO)

The flight from London hit an air pocket and dropped suddenly while en route to Singapore, prompting the pilot to request an emergency landing in Bangkok.

Passengers' heads slammed into the lights above seats, breaking some of the panels, Reuters reported.

Singapore Airlines' chief executive Goh Choon Phong said the company had expressed condolences to the family of the passenger who had died.

"We also deeply apologise for the trauma experienced by all passengers and crew members on this flight," he said in a statement.