In our Ask a Pilot series, pilot Spencer Marker answers aviation-related questions. You can check out past installments here. In this column, Spencer talks about turbulence: what it is, how pilots identify rough air and how they avoid flying through it. The subject is particularly timely following the disturbing video of severe turbulence on a recent flight to Hawaii, which injured dozens of passengers.
How do pilots know when there is going to be turbulence during a flight? —Steve M.
Hey Steve! I get questions about turbulence frequently from friends and family, so I’m glad I can share some of my experience.
Pilots make every effort to give our passengers a safe, expedient and comfortable flight. We employ several tools and rely on our collective experiences to avoid areas of potential turbulence and identify the safest and most comfortable path through the sky.
Identifying and avoiding areas of turbulence
Turbulence is something that is unique to aviation. Unlike freeway driving, where potholes and bumps in the road are easily visible, determining areas of rough air is more challenging as they don’t always present themselves visibly to pilots. Nonetheless, pilots do have tools and experiential knowledge to prevent an inadvertent encounter with rough air.
Pilots are capable of identifying areas of potential turbulence by using their knowledge of meteorology and weather patterns. One of the simplest ways we avoid turbulence is by avoiding areas with thunderstorms. Convective activity is associated with unstable air, as well as strong updrafts and downdrafts. This type of tumultuous atmosphere always leads to bumps. So pilots will make every effort to avoid them.
Knowing where the jet stream is located and its intensity will also give pilots an idea of the ride that can be expected. Jet streams are strong, meandering currents of air that circle the Earth. During wintertime, the polar jet stream, which usually resides over Canada, will dip further south and strengthen. Winds in the jet stream this time of year can top 250mph and can lead to rough rides. Most notably, clear air turbulence.
This type of turbulence is associated with strong and sudden changes in wind speed in the jet stream and is strongest on the cold side (the north side in the Northern Hemisphere). As the name implies, this turbulence presents no or few visible indications of its presence. Therefore, knowing the location and intensity of the jet stream can help pilots develop a plan to avoid areas where clear air turbulence is possible.
Additionally, flights going into mountainous airports like Denver may experience turbulence due to winds being blown across the mountains. At altitude, pilots flying over the front range of the Rocky Mountains can experience this as mountain wave turbulence. Rather than being a series of jostling bumps, mountain wave will present itself as an up and down feeling, much like driving a car enthusiastically on a hilly road.
Other tools for identifying rough air
In addition to pilot experience, one of the best tools pilots use to avoid bumpy rides is called a PIREP. A PIREP is a “Pilot Report” and is communicated to Air Traffic Control by a pilot experiencing some type of weather phenomenon, like turbulence.
Simply put, this means that if an airplane is experiencing some kind of turbulence, its pilots will inform ATC, who will then distribute that information to other airplanes in the area. This gives other pilots the chance to change course or altitude before turbulence is encountered. It is a simple but invaluable tool for pilots of thousands of flights that crisscross the country everyday.
Airlines have also begun a technological initiative to bring more online weather resources into the cockpit. As stated in an earlier article, airlines have begun making use of onboard Wi-Fi to allow flight crews to access weather data in real time.
Managing a bumpy ride
Coupling these tools with a pilot’s knowledge allows flight crew members to accurately predict what kind of rides can be expected. That being said, the atmosphere is a complex, ever-evolving system and sometimes, rough rides will happen unexpectedly. Also, some areas of turbulence are simply too large to avoid completely.
In these instances, pilots will first secure the cabin, including turning on the seatbelt sign and making a passenger announcement. From there, we use all our available resources, including ATC coordination and cockpit technology, to locate a smoother altitude.
To sum up
Thanks again for the great question, Steve. Pilots go to great lengths to ensure our passengers have an enjoyable experience on our airplane. One of the most perceptible ways we do that is by providing a smooth flight. Turbulence is something that no passenger likes to experience and pilots have many tools at their disposal to make their flight as smooth as possible.