The Singapore Airlines (SIA) Flight SQ321 that was rocked by severe turbulence on May 21 climbed and descended rapidly twice in 62 seconds, stunning the passengers with one dying of heart attack, as the aircraft flew over the Irrawaddy Delta region of Myanmar, it emerged on May 25.

One passenger — 73-year-old Briton Geoffrey Kitchen — died, and dozens were injured in the incident. It is the first SIA aviation accident involving a fatality since the SQ006 crash in Taiwan in October 2000.

Also read: What is aircraft turbulence and how common is it? | Explainer

As the flight, which was heading to Singapore from London, experienced sudden severe turbulence over the Irrawaddy Basin during the breakfast service, the pilot declared a medical emergency and diverted the plane carrying 211 passengers and 18 crew members to Bangkok’s Suvarnabhumi Airport, where the plane made an emergency landing at 3.45 pm (4.45 pm Singapore time).

Granular flight data from flight tracking website Flightradar24 shows that the Boeing 777-300ER climbed and descended rapidly twice in 62 seconds, starting from 3:49 pm Singapore time, as the plane was nearing the end of a non-stop flight from London to Singapore, The Straits Times newspaper reported.

During this time, the plane climbed from its cruise altitude of 37,000 feet to 37,400 feet and then dropped to 36,975 feet before settling back onto its cruise altitude.

This indicates that it was the rapid transition between the climb and descent caused by the turbulence — and not the actual change in altitude itself, which was relatively minor — that caused pandemonium in the cabin.

The Flightradar24 data — derived from a global network of ground-based receivers, satellites and radars that receive flight data from aircraft transponders — contradicts some earlier reports, which pinpointed the aircraft descending from 37,000 feet to 31,000 feet between 4.06 pm and 4.10 pm as the cause of the injuries.

This latter transition appears to be the pilots carrying out a controlled descent, most likely to assess the situation before diverting to Bangkok, according to the broadsheet report citing a commercial pilot who has flown both civil and military multi-engine passenger aircraft for more than 20 years.

Speaking on condition of anonymity, the pilot said the rapid climb would have introduced positive G-forces onto passengers, causing sitting passengers to feel like they have been pinned down in their seats.

The subsequent rapid descent would have resulted in negative G-forces, which would have sent unrestrained passengers and other loose items hurtling upwards onto the ceiling of the cabin, he added.

The embattled plane went through another cycle of rapid climb and descent, causing more damage and injuries, with some passengers and objects hitting the roof panels and overhead lockers before being flung back down.

This is reflected in the accounts of passengers on board SQ321 who reported being thrown onto the cabin roof, with Australian passenger Teandra Tukhunen recounting that she was abruptly woken up when she was thrown to the roof and then to the floor.

The G-force data would have been captured by the quick access recorder fitted onboard the aircraft. This is a flight data recorder designed to provide quick and easy access to raw flight data through means such as USB or mobile phone networks.

The Flightradar24 data showed that the Boeing 777 first attained a climb rate of 1,664 feet per minute (fpm) — or 507m per minute, double the height of 52-storey Capital Tower — before descending at 1,536fpm six seconds later. It rapidly returned to a climb rate of 900fpm a mere three seconds later, and then descended at 1,536 fpm after another 10 seconds.

Transport Minister Chee Hong Tat said on Friday that investigators from Singapore’s Transport Safety Investigation Bureau are going through data from the cockpit voice recorder and the flight data recorder.

The United States National Transportation Safety Board’s data from 2009 to 2018 showed that passengers injured in turbulence-related accidents were most often using, waiting for or walking to or from the toilet. The second-most common group was passengers who were seated but not belted up.

Thai hospital says 43 people still under treatment

Forty three people who were on board the Singapore Airlines flight remain hospitalised in Bangkok four days after the emergency, a hospital in the Thai capital said on Saturday.

The 43 patients are in three different hospitals in Bangkok, Samitivej Srinakarin hospital said in a statement.

At Samitivej Srinakarin hospital, where 34 of the patients are, seven are in intensive care — three Australians, two Malaysians, one British and one New Zealander, the statement said.

The other 27 patients from the flight at the hospital include eight British, six Australian, five Malaysian, and two Philippine citizens, the statement said.

Two people were discharged from Samitivej Srinakarin, while two from Samitivej Sukhumvit hospital were transferred to Samitivej Srinakarin to join hospitalised relatives, the statement said.

On Thursday, the Samitivej Srinakarin hospital director told reporters 22 patients had spinal cord injuries and six had brain and skull injuries, but none were life-threatening.

Representational file image.
| Photo Credit: Reuters

A Singapore Airlines flight from London made an emergency landing in Bangkok on May 21 due to severe turbulence, the airline said, with one passengers on board dead and injuries reported.

Singapore Airlines did not say how many people were injured. Multiple Thai media reports said there were 30 injuries.

The Boeing 777-300ER plane with 211 passengers and 18 crew was headed to Singapore when it made the emergency landing, the airline said in a statement.

A spokesperson for Bangkok’s Suvarnabhumi airport said that medical team was on standby.

“Our priority is to provide all possible assistance to all passengers and crew on board the aircraft,” the airline said.

“We are working with the local authorities in Thailand to provide the necessary medical assistance.”

Representational file image.
| Photo Credit: Reuters

A Singapore Airlines flight from London made an emergency landing in Bangkok on May 21 due to severe turbulence, the airline said, with one passengers on board dead and injuries reported.

Singapore Airlines did not say how many people were injured. Multiple Thai media reports said there were 30 injuries.

The Boeing 777-300ER plane with 211 passengers and 18 crew was headed to Singapore when it made the emergency landing, the airline said in a statement.

A spokesperson for Bangkok’s Suvarnabhumi airport said that medical team was on standby.

“Our priority is to provide all possible assistance to all passengers and crew on board the aircraft,” the airline said.

“We are working with the local authorities in Thailand to provide the necessary medical assistance.”