The interior of Singapore Airline flight SQ321 is pictured after an emergency landing at Bangkok's Suvarnabhumi International Airport, Thailand, May 21, 2024. Image Credit: Reuters/Stringer

Dubai: A Singapore Airlines flight fell into an air pocket while cabin crew was serving breakfast before it encountered turbulence, prompting the pilots to request an emergency landing.

The flight from London en route on Tuesday made an emergency landing in Bangkok.

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A 73-year-old British man died during the incident, likely due to a heart attack. Bangkok's Samitivej Srinakarin Hospital said a total of 71 people had been sent for treatment, six of them severely injured. Most of the injuries were caused by blows to the head.

Of the passengers, 56 were Australians, 47 British and 41 Singaporeans, the airline said.

It is the latest drama involving a Boeing plane, after a fuselage panel blew out of an Alaska Airlines 737 MAX in January as well as two fatal crashes in 2018 and 2019.

What exactly happened?

The plane encountered sudden extreme turbulence, Singapore Airlines CEO Goh Choon Phong said, and the pilot then declared a medical emergency and diverted to Bangkok.

Aircraft tracking provider FlightRadar 24 said at 0749 GMT the flight encountered “a rapid change in vertical rate, consistent with a sudden turbulence event”, based on flight tracking data.

“There were thunderstorms, some severe, in the area at the time,” it said.

Weather forecasting service AccuWeather on Tuesday said rapidly developing, explosive thunderstorms near the flight path of Flight 321 most likely contributed to violent turbulence.

“Developing thunderstorms often have strong updrafts, a zone of upward moving air, that rises very rapidly, sometimes at more than 100mph, and can leave pilots will little time to react if it occurs directly in front of the plane,” Dan DePodwin, AccuWeather’s Senior Director of Forecasting Operations, told Reuters.

The sudden turbulence occurred over the Irrawaddy Basin in Myanmar, about 10 hours into the flight, Singapore Airlines said.

“It is not a rare occurrence for big thunderstorms in the Bay of Bengal. There are always the chances of bumps,” said an airline pilot who regularly flies to Singapore and Southeast Asia. The pilot declined to be identified because he is not authorised to speak to the media.

“We were about 30 miles off track flying around the thunderstorms two days ago on the way to Singapore,” the pilot added.

Was not wearing seatbelt cause for most injuries?

A passenger who was on the flight told Reuters that the incident involved the sensation of rising then falling. “Suddenly the aircraft starts tilting up and there was shaking so I started bracing for what was happening, and very suddenly there was a very dramatic drop so everyone seated and not wearing a seatbelt was launched immediately into the ceiling,” Dzafran Azmir, a 28-year-old student on board the flight told Reuters.

“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,” he said.

Most of the passengers he had spoken to had been wearing their seatbelts.

The spokesperson for FlightRadar 24 said with regard to data showing a drop in height, “our initial thinking is the turbulence event is prior to the standard descent from 37,000 to 31,000 feet. That appears to just be a flight level change in preparation for landing.”

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

The interior of Singapore Airline flight SQ321 is pictured after an emergency landing at Bangkok's Suvarnabhumi International Airport, in Bangkok, Thailand May 21, 2024. Image Credit: Obtained by Reuters

What are the most common accidents?

Turbulence-related airline accidents are the most common type, according to a 2021 study by the National Transportation Safety Board.

From 2009 through 2018, the US agency found that turbulence accounted for more than a third of reported airline accidents and most resulted in one or more serious injuries, but no aircraft damage.

The interior of Singapore Airline flight SQ321 is pictured after an emergency landing at Bangkok's Suvarnabhumi International Airport, Thailand, May 21, 2024. R Image Credit: Reuters/Stringer

So then what’s turbulence?

Turbulence describes an event when an airplane hits a strong wind current that can push or pull. The phenomenon can be caused by pockets of hot air rising, or weather systems such as cumulonimbus clouds. At higher altitudes, aircraft might encounter clear air turbulence caused by the differences in speed of air masses.

Smaller planes can also encounter turbulence from larger planes that shake up the air with their engines. Since 1969, multi-aisle aircraft such as the Boeing 747 or Airbus A380 have been given a wide berth from other large planes because of what’s called wake vortex, requiring them to stay several miles apart as they arrive or depart.

What’s severe turbulence and what happens when it occurs?

Severe turbulence refers to intense and unpredictable air movement encountered by aircraft during flight. This turbulence can cause sudden and violent changes in altitude, attitude, and airspeed, posing risks to the safety of passengers and crew onboard. It can result from various atmospheric conditions, such as thunderstorms, mountain waves, or jet streams, and can be challenging for pilots to anticipate and navigate through. Severe turbulence may lead to injuries among passengers and crew and can also cause damage to the aircraft if not properly managed.

About 240 events of severe turbulence were reported to European planemaker Airbus SE between 2014 and 2018, with injuries to passengers and crew occurring on 30% of long-haul flights where such events were reported, and 12% of

What’s the difference between turbulence and clear air turbulence?

Turbulence refers to the irregular and often unpredictable movement of air, which can affect aircraft during flight. It can result from various atmospheric conditions, such as changes in wind speed or direction, temperature gradients, or air masses interacting with each other. Turbulence can vary in intensity, from light to moderate to severe.

Clear air turbulence (CAT) specifically refers to turbulence encountered in cloudless areas of the sky, where there are no visual cues such as clouds to indicate its presence. CAT is often associated with fast-moving air currents known as jet streams, which flow at high altitudes and can disrupt the smooth flow of air around an aircraft. It is typically encountered at cruising altitudes and can sometimes be particularly severe, even though it occurs in clear weather conditions. short-haul flights, according to a briefing document on the phenomenon.

Can turbulence be avoided?

In cases where turbulence cannot be avoided, Airbus recommends pilots fasten their shoulder harnesses and secure loose objects in the cockpit, leave autopilot systems on and possibly descend to a lower altitude.

“More than 75% of these injuries related to turbulence happen at high altitude more than 30,000 feet, at these altitudes you get clear air turbulence that is unpredictable,” said Hassan Shahidi, the CEO of the Flight Safety Foundation.

“The aircraft is designed to withstand these kinds of shocks, but when you have passengers not wearing seat belts they are not protected.”

A Singapore airline aircraft is seen on tarmac after requesting an emergency landing at Bangkok's Suvarnabhumi International Airport, Thailand, May 21, 2024. Image Credit: Pongsak Suksi/Handout via Reuters

What’s Singapore Airlines safety record?

Singapore Airlines hasn’t yet provided details of the accident. The airline has a robust safety record, consistently ranking among the world’s safest. The last fatal accident involving the carrier occurred in 2000, when one of the airline’s Boeing 747 crashed while attempting to take off in the middle of a typhoon, killing 83 people.

In 2001, Singapore Air said four passengers and three cabin crew were hurt when a flight from Kolkata to Singapore experienced unexpected turbulence.

Did climate change increase clear-air turbulence?

A study by Reading University published in 2023 said that clear-air turbulence, which is invisible, had increased with climate change.

While the US and North Atlantic had seen the biggest increase, routes over Europe, the Middle East and South Atlantic had also seen significant rises in turbulence.