What is turbulence, what causes it on an airplane, and why it's not usually dangerous

• Turbulence is chaotic air movement caused by jet streams, mountains, storms, and other disturbances.
• Turbulence in flight is very common, but not necessarily dangerous, since planes are built for it.

Airplane turbulence is often the scariest part of flying, because it can feel like the plane is about to freefall through the sky. But the vast majority of turbulence is not actually dangerous.

It might not seem that way, given the recent news of a Lufthansa flight where seven people were injured during turbulence, and a United flight in February where 25 people were injured in a bump patch of sky.

But airplane turbulence is very common — just think of how many times you've experienced a sudden, wobbly flight. And, despite recent news, instances of turbulence causing injuries are very rare.

Between 2009 and 2021, there were only between five and 18 serious turbulence-related injuries per year, according to the Federal Aviation Administration.

What causes turbulence

The FAA defines turbulence as "air movement created by atmospheric pressure, jet streams, air around mountains, cold or warm weather fronts, or thunderstorms."

Basically, disturbances in the air are going to rock your plane a bit, similar to how disturbances in the water will rock a boat.

In fact, turbulence occurs in any system of moving fluids — waves in the ocean, a cup of tea, plasma on the surface of the sun, the air in your lungs, or the blood in your veins.

Eddies of different sizes form throughout the fluid, move, break apart, and transform. A fluid can be more turbulent if it has a low viscosity, like water or air.

The physics of turbulence are famously illustrated in Vincent Van Gogh's painting "Starry Night."

Exactly how turbulence works, and why it happens, is still a bit of a scientific mystery. Turbulence is chaotic, meaning it's highly sensitive to every little disruption — like a mountain range or buildings forcing air to move around them, or a change in temperature affecting the air's movement.

That makes turbulence highly unpredictable, but it's probably not going to cause the plane to go down or crash.

"Turbulence is normal; it's part of the sky," Patrick Smith, a commercial pilot, told The Washington Post. "Every flight every day encounters some form of rough air. For crews, by and large, we look at it as a comfort issue, not necessarily a safety issue."

Is turbulence dangerous?

Turbulence generally isn't harmful to planes.

"Aircraft are engineered to take a remarkable amount of stresses and strains, and a huge safety margin is built into the designs so that even very severe turbulence will not exceed the design limits of the aircraft," Darren Ansell, a professor of aerospace engineering at the University of Central Lancashire wrote in The Conversation in 2016. "The level of turbulence required to bend a wing spar is something even most pilots will not experience in a lifetime of traveling."

If you do look out your plane window and see the wings flexing and bending in the rough air, don't be alarmed. That's how they're designed so that they withstand turbulence. If they were totally rigid, they'd be prone to snapping off.

Severe turbulence can cause a plane to drop so suddenly that pilots temporarily lose control. But, again, that's not enough to crash the plane.

That's not to say it's never happened. In 1966, human error and turbulence combined to bring a plane down over Mount Fuji. But, according to Ansell, aircraft design has improved since then, and a modern airplane would not crash under the same conditions.

Today, severe turbulence poses more of a threat inside the plane. In rare cases, it can throw people out of their seats and cause injury, since human bodies don't handle being bumped or slammed into hard objects very well.

The FAA says that one of the easiest ways for passengers to avoid being injured when turbulence occurs is to always wear their seatbelt when seated. Hence the "fasten your seatbelt" sign that's strategically placed above every row on a plane.

How to deal with turbulence on your flight

If you're especially freaked out by turbulence — and we can't blame you for that — it might help to select a seat in the middle of the plane, over the wings.

It won't make a huge difference, Smith told the Post, but it's slightly less bumpy than the tail.

To protect yourself from turbulence-induced injury, wear your seatbelt so you don't get thrown around the cabin. Securing your personal belongings can also help, so they don't go flying and strike anybody if the plane suddenly lurches.

Sometimes, though, the worst part of run-of-the-mill turbulence is the thoughts it can give you. It's common to get anxious that something more is happening when the flight gets bumpy.

Remembering the facts can help: Turbulence is all around us. Planes have been soaring through it safely for decades. Only a minuscule fraction of turbulence incidents cause injuries. And, most of all, turbulence does not have a track record of downing planes.