May 21 (Reuters) - There was little warning of the chaos

that was about to be unleashed onboard Singapore Airlines flight

SQ321.

With around three hours left on the journey from London to

Singapore, Malaysian student Dzafran Azmir got the uneasy

feeling the Boeing 777-300R plane was tilting upwards and

beginning to shake.

The 28-year-old braced himself and checked he had his

seatbelt on. He did. Many of the other passengers did not, he

said.

"Suddenly there was a very dramatic drop so everyone seated

and not wearing seatbelt was launched immediately into the

ceiling, 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," Azmir told Reuters.

"People dropped to the ground, my phone flew out of my hand

and went a couple aisles to the side, people's shoes flung

about," he added.

One passenger was killed and 30 injured after the flight

from London fell into an air pocket before encountering

turbulence en route on Tuesday, forcing it to make an emergency

landing in Bangkok, officials and the airline said.

"The crew and people inside lavatories were hurt the most

because we discovered people just on the ground not able to get

up. There were a lot of spinal and head injuries," Azmir said.

The captain informed passengers they would be making an

emergency landing in Thailand's capital Bangkok.

Once the plane was on the tarmac, nurses and rescue workers

came in to check on the injured, Azmir said.

"I don't think they anticipated how bad it was," he

said.

Ambulances later arrived and Azmir said he saw at least 8

people on stretchers being pulled out of the emergency exits. It

took 90 minutes to evacuate the plane, he said.