“We can confirm that there are injuries and one fatality on board the Boeing 777-300ER,” the carrier said in a statement. “We are working with the local authorities in Thailand to provide the necessary medical assistance and sending a team to Bangkok to provide any additional assistance needed.”

The widebody aircraft with 211 passengers and 18 crew on board was traveling from London Heathrow and diverted to Bangkok’s Suvarnabhumi Airport after encountering the turbulence. Unverified photos posted on social media showed food and other loose items strewn across the cabin floor. 

Airports of Thailand said in a separate statement that medics were dispatched to the scene to assist passengers, and that those with minor or no injuries are awaiting transfer to the original destination. Singapore Airlines said 18 that individuals have been hospitalised, and another 12 are being treated in local hospitals.

Fatalities are extremely rare in incidents of turbulence, particularly during travel at cruising altitude that’s considered the most stable part of the journey. Carriers routinely caution passengers to keep their seat belts fastened even when they have been switched off as unforeseen turbulence may still occur. 

Wake Vortex

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 short-haul flights, according to a briefing document on the phenomenon.

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 to stay several miles apart as they arrive or depart.

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. 

Weather Conditions

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.

The aircraft involved in Tuesday’s incident took off from London at 10:38 pm local time the previous day, according to FlightRadar24. The plane operating flight SQ321 was 16 years old, and is one of Singapore Air’s 23 777-300ERs. Boeing Co. didn’t immediately have a comment on the incident.

In 2001, Singapore Air said four passengers and three cabin crew were hurt when a flight from Kolkata to Singapore experienced unexpected turbulence. Emirates, the Dubai-based carrier said in early 2010 that 20 passengers on a flight from Dubai to Kochi in India suffered “minor injuries” when the aircraft “encountered a short period of heavy turbulence prior to descent.”

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.