(Bloomberg) -- The violent turbulence that hit a Singapore Airlines Ltd. flight on Tuesday can fling passengers around with such force that it’s as dangerous as falling headfirst off a ladder or diving into a shallow concrete swimming pool, a senior emergency physician said.

One British man was killed and seven other people critically injured after Flight SQ321 ran into severe turbulence as it entered Thai airspace. The giant Boeing Co. 777 jet made an emergency landing in Bangkok.

Passengers who aren’t wearing seatbelts when an aircraft suddenly loses altitude like that are exposed to huge vertical load forces, said Rohan Laging, deputy director of emergency services at Melbourne hospital group Alfred Health. They can be rammed into the roof of the cabin — as they were on the Singapore Air plane — running the risk of serious spinal injury, head trauma or internal organ damage as their bodies abruptly decelerate, he said.

The dangers posed by turbulence have been thrust into the spotlight by the fatal incident. The passenger who died was 73 years old and suffered a suspected heart attack, while more than a dozen others were hospitalized with head and arm injuries. Such incidents are so rare that airlines typically don’t mandate passengers wear seatbelts unless bad weather is expected.

“I doubt the average consumer would be aware of the risks,” Laging said.

He described the Singapore Air flight as “a very uncommon event” with a “terrible outcome,” adding that he’s never treated anyone injured by air turbulence and that house fires, car accidents and ladders at home remain far more lethal.

The crew and passengers on the long-haul service from London to Singapore were caught off-guard. Personal belongings, food and people were hurled around the cabin, crashing into overhead lockers and causing oxygen masks to deploy from the ceiling.

Blunt trauma incidents, when bodies collide with each other or hard surfaces, are more dangerous for elderly passengers, those on blood-thinning medication, or people with existing health complaints, Laging said. Fortunately there’s a lower risk of penetrative injuries because many surfaces inside aircraft cabins are intentionally rounded, he said.

Turbulence can occur when a plane hits a strong air current that pushes or pulls the airframe. The phenomenon can be caused by pockets of hot air or powerful weather systems. At higher altitudes, aircraft might encounter hard-to-identify clear air turbulence caused by air masses with differing velocities.

Forecasting is also a challenge, Hong Kong-based Ping Cheung, co-chair of an expert team under the World Meteorological Organization, said.

While wind and upper air temperature forecasts are pretty accurate and used by airlines every day to select the most efficient route, “in terms of turbulence and convections, that score is far less,” said Cheung, who is also a senior scientific officer for the Hong Kong Observatory.

Unanticipated turbulence is also dangerous because pilots may not have taken precautionary measures, said Paul Weatherilt, general secretary of the Hong Kong Aircrew Officers Association.

“It surprises you and you might not have people strapped in,” he said. “This is the problem.” 

Passengers tend to think they’re well protected, particularly in the largest commercial jets that can feel very quiet and safe, Weatherilt said. It’s particularly tough to scare people into wearing seatbelts when the flight is proceeding smoothly, he said.

Flight Safety Foundation Chief Executive Officer Hassan Shahidi, asked how passengers can minimize their risk, said it’s pretty simple.

“Wear your seatbelt at all times and follow the cabin crew’s instructions,” he said. “If you do those kinds of things, you’ll be safe.”

--With assistance from Charlotte Ryan and Danny Lee.

©2024 Bloomberg L.P.