The death of a Briton and the injuries suffered by dozens of people aboard a Singapore Airlines flight that hit severe turbulence this week highlighted the potential dangers of flying in unstable air.
Based on witness accounts, the number of injuries and the sharp descent of the plane, experts point out the significant safety risks that in-flight turbulence poses to passengers and airline crews.
Although turbulence-related deaths are fairly rare, injuries have accumulated over the years. Some meteorologists and aviation analysts note that reports of encounters with turbulence have also increased and point to the potential effects that climate change may have on flying conditions.
However, most incidents of airplanes crashing in rough air are minor, and airlines have made steady improvements to reduce turbulence accident rates over time. Experts advise air travelers to remain alert and stress the importance of wearing seat belts whenever possible as a first line of protection.
What is turbulence?
Turbulence is essentially unstable air that moves unpredictably. Most people associate it with strong storms. But the most dangerous type is clear-air turbulence, which often occurs without visible warning in the sky.
Clear air turbulence most often occurs in or near high-altitude rivers of air called jet streams. The culprit is wind shear, which occurs when two huge air masses close together move at different speeds. If the speed difference is large enough, the atmosphere cannot withstand the stress and breaks up into turbulent patterns like eddies in water.
“When there is strong wind shear near the jet stream, air can overflow. And that creates these chaotic movements in the air,” said Thomas Guinn, chair of the department of applied aviation sciences at Embry-Riddle Aeronautical University in Daytona Beach, Florida.
It is difficult to track the total number of turbulence-related injuries worldwide. But some individual countries publish national data.
More than a third of all airline incidents in the United States between 2009 and 2018 were related to turbulence, and most of them resulted in one or more serious injuries but no damage to the plane, the National Transportation Safety Board reported. .
Between 2009 and 2022, 163 people were injured seriously enough during turbulence to require hospital treatment for at least two days, according to NTSB figures. Most of them were flight attendants, who are especially at risk since they are more likely to be out of their seats during a flight.
Investigations are underway into what happened during Tuesday's Singapore Airlines flight. The airline said the Boeing 777-300ER descended 6,000 feet in about three minutes after experiencing severe turbulence over the Indian Ocean.
Preliminary casualty figures from the airport and a hospital in Bangkok, where the plane heading from London to Singapore landed in the middle of a storm, indicated that, in addition to one death, six or seven passengers were seriously injured. Dozens of other travelers and crew members were reported to have suffered moderate or less serious injuries.
“It is not uncommon to have encounters with turbulence that cause minor injuries, such as a broken bone,” said Larry Cornman, a project scientist at the National Science Foundation's National Center for Atmospheric Research who has long studied the turbulence. “But fatalities are very, very rare, especially on large transport aircraft.”
According to Stuart Fox, director of flight and technical operations for the International Air Transport Association, the last reported clear-air turbulence-related death on a major airline occurred in 1997. Some deaths have been reported on smaller aircraft since then, including a death on a private jet last year, Fox said.
The now standardized safety procedures have significantly helped prevent more cases of serious injuries over the years. Fox said. They include checking weather forecasts, having pilots report when they encounter turbulence and suspending cabin service when planes encounter rough air.
Can pilots avoid turbulence?
Pilots use a variety of methods to avoid turbulence, including the use of a weather radar display. Sometimes they can simply see and fly around storms.
But clear-air turbulence “is a whole other animal,” according to Doug Moss, a former airline pilot and safety consultant. It can be devastating, he said, “because the moment before the incident can be very quiet and people are caught off guard.”
Air traffic controllers will warn pilots when another plane enters clear-air turbulence, Moss said. Many pilots also watch the upper-level jet streams along their route for signs of wind shear and then plan to fly above, below or around those areas, he said.
Modern airplanes are strong enough to withstand almost any turbulence. Cabin areas, such as overhead bins, may suffer cosmetic damage, “but these do not affect the structural integrity of the aircraft,” Moss said.
Is climate change causing increased turbulence?
Some scientists note that reports of encounters with turbulence are increasing. There are several possible explanations for this, but several researchers have pointed out possible climate impacts.
Guinn of Embry-Riddle Aeronautical University explains that some predict that climate change could alter the jet stream and increase wind shear, consequently causing air turbulence.
In a statement on Tuesday, Paul Williams, a professor of atmospheric sciences at the University of Reading in England, said there was “strong evidence that turbulence is increasing due to climate change.”
Williams said his research team recently found that severe clear-air turbulence in the North Atlantic has increased by 55% since 1979, for example. The team's latest projections point to severe turbulence in the jet streams could double or triple in the coming decades if global conditions continue as expected, she said.
Still, others say other factors could also be at play. Cornman said there could be an increase in overall air traffic, which may increase encounters with turbulence as the number of flight paths increases, including those in areas of higher turbulence.
How can travelers stay safe?
In short, buckle up. Turbulence can be difficult to predict, but experts stress that the first line of defense in the air is to keep your seat belt fastened, whenever possible.
“Airplanes are generally built to withstand turbulence,” Guinn said, noting that passengers not wearing seat belts are a big source of in-flight turbulence injuries. Although no precaution is foolproof, wearing a seat belt greatly increases a person's chances of avoiding serious injury, she said.
“Wear your seat belt,” Guinn said. “That's just a really quick fix to prevent injuries.”
Grantham-Philips writes for the Associated Press. Chalida Ekvitthayavechnukul in Bangkok and David Koenig in Dallas contributed reporting.
