Videos and pictures revealing chaotic scenes aboard the Singapore Airlines flight SQ321 are widely circulated on the internet after the passenger plane encountered what the airline described as “sudden extreme turbulence.”
A 73-year-old British man died in the incident probably after suffering a heart attack, while dozens of other passengers were injured. The flight made an emergency landing in Bangkok, Thailand.
The incident highlights that turbulence can be dangerous and fatal. One type of turbulence that can be particularly difficult for pilots is called the clear-air turbulence. Here’s all you need to know about clear-air turbulence.
What Is Clear-Air Turbulence?
Clear-air turbulence is a “typically very violent” phenomenon that takes place at high altitudes, typically between 23,000 and 39,000 feet above sea level, Hassan Shahidi, president and CEO of the Flight Safety Foundation, told CBS News.
What makes clear air turbulence dangerous is that, unlike weather-related turbulence, called convective turbulence, it is not visible beforehand. To avoid severe turbulence, flights are normally diverted or follow a holding pattern, but if it can’t be seen in advance, pilots can’t adapt to avoid it, he said.
What Causes Clear-Air Turbulence?
Airplanes often fly through masses of air called jet streams. Within these streams, multiple layers of air flowing at different speeds “almost on top of each other,” Daniel Adjekum, a pilot and aviation safety consultant, told CBS News. Different temperatures create friction, which in turn, causes “a lot of disturbance,” Adjekum said.
Storms or other weather conditions cause convective turbulence, during which air is heated and displaced, resulting in high levels of moisture that are easily detectable with flight instruments. Clear-air turbulence doesn’t have as high a moisture content, so radar and other instruments can’t detect it until it’s too late, he said, adding, “That is what makes it very insidious.”
Climate change also plays a role as warmer air caused by carbon dioxide emissions created stronger wind shear at higher altitudes, which can cause clear-air turbulence. According to a 2023 study, clear-air turbulence has increased by 41% over the past 40 years.
Clear-Air Turbulence Behind Singapore Airlines Flight Tragedy?
Experts were reluctant to say whether clear-air turbulence was behind the scene aboard Singapore Airlines flight SQ321. The airline said the deaths and injuries aboard the plane were caused when the plane “encountered sudden extreme turbulence.”
The airline said the plane was flying at an altitude of 37,000 feet, which put it in an area of clear-air turbulence, but experts pointed to thunderstorms in the area that could have caused the turbulence.
Robert Sumwalt, ex-chairman of the National Transportation Safety Board and a pilot, said on CBS Evening News that he was “too early to know for sure” the cause of the incident.
