What You Need to Know About Turbulence on Airplanes

Countless travelers have experienced the distinct anxiety-inducing sensation of turbulence on flights: Eyes squeezed shut, hands clamped to the armrests for dear life, bracing for the roller coaster to come.

Recent incidents have left dozens of passengers with injuries. Last month, seven passengers on a Lufthansa flight from Texas to Frankfurt were hospitalized with minor injuries after their plane encountered severe turbulence as it flew over Tennessee. And in December, about two dozen people, including an infant, were hurt on a Hawaiian Airlines flight from Phoenix to Honolulu that hit rough air shortly before landing.

The recent reports raise questions about whether turbulence is getting more frequent and intense.

We spoke to a handful of experts to learn more about the tricky-to-predict weather phenomenon. Here’s what they said.

What is turbulence?

Turbulence is unstable air movement that is caused by changes in wind speed and direction, such as jet streams, thunderstorms, and cold or warm weather fronts. It can range in severity, causing minor to dramatic changes in altitude and air speed.

It’s not just associated with inclement weather, but can also occur when skies appear placid. And it can be invisible both to the eye and weather radar.

There are four classifications for turbulence: light, moderate, severe and extreme. In cases of extreme turbulence, pilots can lose control of the airplane and there can even be structural damage to the aircraft, according to the National Weather Service.

Is turbulence increasing? And if so, why?

Recent research indicates that turbulence is rising and that this change is sparked by climate change, specifically elevated carbon dioxide emissions affecting air currents.

Paul Williams, a professor of atmospheric science at the University of Reading in England, has studied turbulence for more than a decade.

Dr. Williams’s research has found that clear air turbulence, which occurs most frequently at high altitudes and in winter, could triple by the end of the century. He said that this type of turbulence, of all categories, is increasing around the world at all flight altitudes.

His research suggests that we could encounter bumpier flights in the coming years, which could potentially result in more passenger and crew injuries.

How is turbulence monitored and measured?

Meteorologists rely on a variety of different algorithms, satellites and radar systems to produce detailed aviation forecasts for conditions such as cold air, wind speed, thunderstorms and turbulence. They flag where and when turbulence might happen.

Jennifer Stroozas, a meteorologist at the National Weather Service’s Aviation Weather Center, called turbulence “definitely one of the more challenging things to predict.”

Using these forecasts, in addition to guidance from air traffic controllers, pilots attempt to skirt turbulent areas by adjusting their altitude to find the smoothest ride. This means flying higher or lower than the altitude where forecasters predict turbulence, and potentially burning more fuel than initially anticipated, an endeavor that can be costly.

Robert Sumwalt, a former chairman of the National Transportation Safety Board who now heads a new aviation safety center at Embry-Riddle Aeronautical University, stressed that it was impossible to prevent or predict all turbulence.

“There is always the possibility of unexpected rough air,” Mr. Sumwalt said. “Generally it’s not going to hurt you and not going to pull the wings off the airplane.”

Turbulence also presents a greater threat to small planes that are more susceptible to changes in wind speed, rather than larger commercial airliners, Ms. Stroozas of the National Weather Service said.

Is it that dangerous? How can I stay safe during turbulence?

Airplanes are designed to withstand rough conditions and it is rare for aircraft to incur structural damage because of turbulence.

But turbulence can toss passengers and crew members around, potentially causing grave injuries. Multiple experts emphasized that staying seated and keeping your seatbelt on as much as possible during flights were the best ways to reduce risks.

“If you stay fastened you’re far less likely to incur an injury,” said Thomas Guinn, a professor of applied aviation sciences at Embry-Riddle Aeronautical University.

In severe turbulence, the vertical motion of the plane will exceed gravity’s pull, Dr. Williams said.

“What that means is that if you’re not seat belted, by definition, you’ll become a projectile, you’re a catapult, you will lift up out of your seat,” he said.

Fatalities caused by turbulence, while exceedingly uncommon, do happen. The last time a passenger on a commercial flight died from a turbulence-related injury was in 1997, when a United Airlines flight from Tokyo to Honolulu experienced severe turbulence over the Pacific Ocean, according to an N.T.S.B. investigation. This passenger was not wearing a seatbelt and flew up from her seat, possibly striking her head on the luggage bin, according to the investigation.

Last month, a former White House aide aboard a business jet traveling from New Hampshire to Virginia died from fatal injuries initially attributed to severe turbulence. However, a preliminary N.T.S.B. investigation found that the airplane’s pilots turned off a switch stabilizing the aircraft, causing it to briefly oscillate in the air.

What about babies on laps?

Children younger than 2 years old are allowed to be carried on an adult’s lap during flights, but many industry experts, citing dangers such as turbulence, believe this practice should be prohibited.

Last month, the Association of Flight Attendants-CWA, a union representing about 50,000 flight attendants across 19 airlines, renewed its decades-long push for every passenger to have their own seat, no matter their age.

Sara Nelson, the union’s president, said in an interview that with turbulence becoming “much more common” lately, the need for young children to be properly secured in child safety seats during flights is a greater priority.

“We are talking about events in the cabin that are potentially deadly but survivable when you do the right things to protect yourself,” Ms. Nelson said.

Unexpected turbulence is the leading cause of pediatric injuries on airplanes, according to the F.A.A., which has detailed information about various child restraint systems and how to correctly install them onto airplane seats. Some of these products are compatible for both cars and airplanes.

For decades, the F.A.A. and N.T.S.B. have urged parents to secure young children in their own ticketed seats and in an approved safety seat. The American Academy of Pediatrics also echoes this guidance. There is no federal law requiring these measures.

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