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FlyerTalk 101: Turbulence Explained

Every flyer has had experience with turbulence, whether it is enjoying the thrill of it, or grabbing onto the armrests hoping it quickly subsides. Although most FlyerTalkers may enjoy it or not even notice it, turbulence can pose a serious safety threat to passengers and crew inflight. In 2019, an Air Canada flight left 37 injured after the aircraft experienced unexpected dips and dives, while a Turkish Airlines flight hospitalized 30 after severe shaking. Granted, these aircraft did not crash as a result of turbulence, but it just goes to show that this phenomenon is not something to scoff at. Now, I know as a community of frequent flyers, it can be easy to become complacent when it comes to turbulence. But, it is important to remember that these violent bumps can be very unpredictable, and will cause more than just a few spilled drinks if you aren’t careful.

What is Turbulence?

According to the National Weather Service, turbulence is the “irregular motion of an aircraft in flight, especially when characterized by rapid up-and-down motion, caused by a rapid variation of atmospheric wind velocities.” More simply, it is the bumps and shakes you feel inflight that are caused by sudden changes in airflow. Meteorologists break down turbulence intensity into four categories:

  1. Mild: light bumps with minor changes in altitude
  2. Moderate: more intense than mild, and may cause strain on passengers, but there is no loss of control of the aircraft
  3. Severe: abrupt changes in altitude that can cause a violent strain on passengers, dislodge stored items, and momentarily knock the aircraft out of control
  4. Extreme: tosses the aircraft into a possibly uncontrollable state and can cause structural damage

On most flights, passengers can expect turbulence to be between mild and moderate. However, when faced with phenomena such as clear air turbulence, mountain waves, or thunderstorms, it can be severe or extreme and cause violent jolts. Although modern aircraft are built to withstand turbulence and will rarely be knocked out of the sky because of it, turbulence is still a danger to passengers who are standing or not wearing seatbelts.

How Do Pilots Predict Turbulence?

Turbulence is a tricky phenomenon that cannot always be predicted; however, pilots have an array of resources available to help identify and maneuver around upcoming chop. These include weather reports, radio warnings from other crews, and pilot reports in the form of PIREPS. PIREPS are reports of actual weather conditions made to air traffic control (ATC) or flight service stations (FSS) who can relay the information to other aircraft in the area. In an interview with Ask the Pilot author Captain Patrick Smith, he explained, “Predicting the where, when, and how much of turbulence is more of an art than a science. We take our cues from weather charts, radar returns, and, most useful of all, real-time reports from other aircraft.”

The good thing about radio and pilot reports are that they can be received anywhere from five to 20 minutes out, so flight crews have time to make altitude or course adjustments to minimize the effects of turbulence, or avoid it altogether.

Why is the Seatbelt Sign Left On Even Though I Feel No Turbulence?

Turbulence is a reality of flying, and the possibility of it can leave the dreaded seatbelt sign on for longer than anticipated. Although it can be annoying, in most cases, there is a legitimate safety reason why the sign remains illuminated, such as potential clear air turbulence ahead.

However, I know there is a debate over why the seatbelt sign remains on for extended periods during flight. Is it due to genuine safety concerns, or because the cabin crew asked the pilots to keep it on for selfish reasons? I’m not here to argue one side or the other; however, the thought that the latter may be true is what leads to passenger frustration, and eventual disregard for the sign. In a thread in the FlyerTalk forums, a user posted a question about why their pilots kept the sign illuminated for most of the flight when, to their knowledge (using public data), there was not much turbulence in the area that day. One user responded to the thread with a different perspective:

“I tend to trust the judgment of trained professionals over my own knowledge of meteorology. I also don’t have access to the many “ride reports” which are called or sent in by enroute aircraft and provide up-to-the-minute information about conditions in specific locations.

One doesn’t have to do too much searching to find the reports of messy accidents involving injured crew and passengers from sudden and unexpected turbulence.

I’d rather wait 5 minutes for my drink.”

Another, who is a United Airlines pilot, chimed in to shed some light on how turbulence forecasting is not as easy as it seems:

“I recently had a flight to EWR/ZRH where the turbulence forecast over the tracks was horrendous. 3-4 hours of moderate turbulence with no way around it. We briefed the passengers at the gate, before push, and during level off that it was going to be pretty rough for an extended period of time in about 2 hours into the flight.

As we coasted out, our dispatcher sent a report that the lower altitudes (F280-F300) are much better than the planned F350.

Requested lower and ended up flying at F290 where it was nothing worse than light chop here and there the whole way. Meanwhile our iPads kept showing red areas of turbulence nearly the entire ocean crossing. The other airplanes higher were getting beat up pretty bad and unable to descend to get out of it because of traffic like us.

Landed uneventfully in ZRH, after blocking in the three of us debriefed on what a great move that it was to opt to fly lower and adjusting our fuel consumption to make it work out. How this could have been a very long and uncomfortable night if we didn’t.

Minutes later as pax were deplaning a “Multi-Million Mile” passenger approached and accused me of deliberately lying; completely overdoing the turbulence reports to reduce workload for the flight attendants. “I’m onto your game and rest assured this seat belt sign abuse will be reported to United.”

There’s no winning in a situation like that and I just responded I’d try to do better next time, sorry about that. I was the one standing by the cockpit door as the other two pilots were packing their things up. They listened to this guy’s diatribe and I could hear them quietly laughing behind me.

Bottom line, can’t win for trying!

We don’t keep the seat belt sign on to create issues…honestly. If it’s bumpier than planned, sorry. If it’s smoother than reported, sorry. It’s also not a conspiracy against your bladders or a means to impede service.”

Note: If you have an emergency that forces you out of your seat when the sign is illuminated, then I am not discouraging you from going about your business, but stay alert to the jostling of the aircraft.

Comfort Concern Over Safety Concern

Although some turbulence can be dangerous, most of the time, it is just a nuisance. For pilots, they are doing everything they can to avoid turbulence and keep the ride smooth, but it is not always possible. In an interview with Captain Steve Allright, a pilot for British Airways, he explained how flight crews manage turbulence and how, for the most part, it is more of a comfort concern than a safety concern. He explained, “Our endeavors to fly at an altitude that has been reported as smooth may be prevented by several constraints, such another aircraft occupying that level, or the weight of the aircraft at that time. Whatever the circumstances, your pilot will find the most comfortable path to your destination without compromising your safety. Just like you, we experience the movement and would prefer a smoother ride.”

Although many FlyerTalkers may not even notice the effects of turbulence anymore, if you are someone who finds the bumps annoying or frightening, it is suggested you sit over the wings near the aircraft’s center of lift and gravity, and to avoid the aft-most section of the plane.

Bottom Line

Even if you think the seatbelt sign is illuminated in error, or for selfish reasons, it is important to trust the professionals who have more information about the environment they are flying through. And if you are someone who does fear turbulence, remember that in most cases, it is more of an inconvenience to passengers than a threat to the safety of flight.

htb May 21, 2020

@ConnieDee: good protocol for the pilots would be to explain that they are leaving the seatbelt signs on for longer than appears necessary because . I'm sure people would be much more understanding.

ConnieDee May 15, 2020

Yes, I'm sure that some pilots forget to turn it off. I wonder what a good procedure would be to remind them. We could ring the flight attendants, but wouldn't they remind the pilots anyway when everyone starts getting up? Can cabin crew nudge pilots about this or would it violate some pecking order?

picturegal May 14, 2020

"Waiting an extra 5 minutes for my drink" is not the same thing as waiting 3 hours to go to the bathroom. I still think some pilots forget to turn off the seat belt light.

FliesWay2Much May 14, 2020

If you want to know the predicted turbulence and other aviation weather forecasts, Check out the NOAA Aviation Weather Center's website: www.aviationweather.gov. Some other countries' meteorological services also post aviation weather.