In brief
- Turbulence is graded on a scale, including light, moderate, severe and extreme turbulence
- Turbulence is measured using a scale called the Eddy Dissipation Rate (EDR)
- Turbulence is a safe and normal part of flying and planes are built to withstand levels of turbulence much higher than pilots and passengers are ever likely to experience
- Breathing exercises, grounding techniques and mindfulness can help to calm you during turbulence
Understanding turbulence levels
Turbulence is classified by the industry into four categories according to its severity. the scale includes light turbulence, moderate turbulence, severe turbulence, and extreme turbulence.
Any mention of turbulence can scare nervous flyers, but the reality is that turbulence is safe, normal and should be expected on every flight.
Here, we’re going to explore the different levels of turbulence, provide a basic explanation of how pilots measure turbulence, and provide some resources that can help you to understand what causes turbulence and why it’s nothing to worry about.
How is turbulence classified?
In the world of aviation, there’s an agreed upon rating for turbulence with clear classifications.
As a fearful flyer, you’ve probably come across these classifications before: light, moderate, severe, and extreme turbulence.
Turbulence is complicated to describe. We all experience it in slightly different ways. (An experienced pilot may not even register light turbulence, but a fearful flyer might, for example.)
To help you understand what turbulence is, how it feels and what it means, we’re going to describe each type of turbulence in three ways:
- The science
- The passenger perspective
- The pilot’s perspective
Light turbulence
The science:
On the turbulence scale, light turbulence usually measures around EDR 0.1–0.2 (EDR, or eddy dissipation rate, is a standard way to quantify turbulence – more on this later).
When it’s in the air, the aircraft may experience small, rapid variations in airspeed (less than 15 knots), slight changes in altitude (tens of feet rather than hundreds), and minimal changes in attitude (pitch, roll, or yaw).
Passenger perspective:
It feels like a gentle ripple through the cabin. Your drink might wobble in its cup, but you can still read, chat, or type without much trouble.
Pilot perspective:
It’s very minor. It rarely requires a change in altitude or course. Pilots may switch on the seatbelt sign as a precaution, especially if the turbulence is forecast to continue or increase in intensity.
Moderate turbulence
The science:
Moderate turbulence generally measures around EDR 0.2–0.4. Here, airspeed variations can be 15–25 knots, altitude can change by a few hundred feet, and there are more distinct shifts in aircraft attitude. The autopilot remains in control but may work harder to maintain stability.
Passenger perspective:
It’s more of a noticeable jostle. Drinks might spill, walking down the aisle becomes a challenge, and you’ll be grateful for your seatbelt.
Pilot perspective:
Pilots may slow the aircraft to turbulence penetration speed (a safe, recommended speed for comfort and airframe stress reduction). Communication with air traffic control may include requests to change altitude or route to find smoother air.
Severe turbulence
The science:
Severe turbulence typically measures EDR 0.4–0.6 or higher. Airspeed variations can exceed 25 knots, altitude changes can be several hundred feet in seconds, and there are abrupt, significant changes to pitch and roll. The autopilot may disengage, requiring pilots to take manual control.
Passenger perspective:
This feels intense, like an unexpected rollercoaster drop combined with side-to-side sways. You’ll be firmly in your seat, and anything unsecured might shift or fall.
Pilot perspective:
The focus becomes managing the aircraft’s attitude and keeping it within safe limits. Pilots avoid making control inputs that could worsen structural loads, relying on training and quick assessment to get the aircraft back into smoother conditions as soon as possible.
Extreme turbulence
The science:
Extreme turbulence, with EDR above 0.6 is rare. It can cause violent changes in airspeed and altitude, potentially exceeding the structural limits of the aircraft if prolonged (though aircraft are designed with large safety margins). The forces involved can momentarily make control of the aircraft difficult.
Passenger perspective:
It’s a short but overwhelming experience. You might feel pressed into your seat, then briefly lifted, with strong sideways jolts. Thankfully, commercial flights almost never encounter this level of turbulence.
Pilot perspective:
Extreme turbulence is nearly always spotted on radar, through weather reports, or from other pilots’ reports. If encountered unexpectedly, the priority is to maintain structural safety, communicate with ATC, and exit the affected area as quickly as possible.
Feel the bumps, don’t fear them
While you may experience light. moderate and even severe turbulence on a flight, it’s rare this will happen. Instead of trying to classify turbulence, focus on the things you can control. Like being calm, relaxed and in the moment.
If you need some help, download our free Calm Flight Toolkit or visit the Help Desk for resources.
Please share this article with anyone who might benefit from it.
FAQs
Pilots will have developed an intuitive feel for turbulence and can grade it. There’s a tendency for passengers to over-estimate the severity of turbulence. In the end, it doesn’t really matter. Planes can – and will – safely fly through turbulence. It might be uncomfortable, but it’s not unsafe.
Yes. it’s nothing to do with the design of the plane, but the size. It will take more energy to move a large plane than a small one. If you both planes (an A320 and an A380, for example) flew through the same rough air, it’s likely that turbulence would be felt slightly more acutely on the smaller A320. That’s because the A380 is almost twice as long and with twice the wingspan. Both planes would remain safe, of course.
Some forms of turbulence, like those caused by storm clouds, can be seen and avoided. However, as its name suggest, clear air turbulence is impossible to spot. That doesn’t mean that pilots are on their own. they have access to increasingly accurate forecasts and can get real-time information from other pilots to plot the smoothest course. Sit back and relax, you’re in great hands.