Turbulence can make even the most frequent flier feel a little jittery or disturbed. And with nearly 240,000 flights expected over the long Thanksgiving weekend, at least a few are likely to encounter rough skies, according to the Federal Aviation Administration.
“It almost always starts to get bumpy as soon as we turn off the fasten seatbelt sign,” Morgan Smith, a Boeing 737 pilot, joked. “But honestly, almost everything about turbulence is annoying and not dangerous.”
Fortunately, the start of Thanksgiving weekend is not expected to be particularly bumpy. “There’s nothing extreme about the jet stream,” said Alek Mead, an Alaska Airlines dispatcher. “Only through Friday, there may be some thunderstorms in the Gulf Coast, around Houston and Memphis that could affect turbulence.”
To help pilots find “smooth skies,” researchers at the National Center for Atmospheric Research developed a forecasting model that takes a meteorological measurement of atmospheric turbulence called the vortex dissipation velocity and predicts it over an 18-hour period.
The forecast at the top of this article shows the maximum turbulence predicted at all altitudes where commercial jets fly – so an area shown as predicting moderate turbulence may contain altitudes with calmer air. Pilots can use tablets in the cockpit to view more specific forecasts that show which areas of turbulence are present at what altitude, allowing them to navigate over, under or around those zones.
“It’s not an exact science,” said Mrs. Smith. “But it helps us plan for turbulence during a flight, such as having the flight attendants delay service until we’ve passed an area or notifying passengers of potential turbulence during the welcome aboard announcement.”
Airline shippers like Mr. Mead prepare flight plans hours in advance using software with dozens of weather and air traffic sources to avoid turbulence-prone zones. During the flight, the dispatchers continuously communicate with the pilots and guide them through unexpected bumps. “These models work well, they are a valuable tool in our pocket. They show us the big picture, where everything will be,” he said.
Aircraft also have sensors that read and automatically report the G-forces stressing the aircraft during flight. These reports are added to a database that other flight coordinators monitor. If turbulence starts to build up in an area, other planes coming via the same route may begin to avoid it.
What is Turbulence?
“To really simplify, turbulence is actually a disrupted airflow,” Ms Smith said. “If air changes direction or speed, we get some bumps.”
She compared it to being on a boat on the water.
“As the water moves, so does the boat,” she said. “Like water, air is liquid and has the same effect on an airplane.”
Occupants may feel a slight tension against seat belts or shoulder straps. Unsecured objects may move slightly. Food can still be served and walking can be done with little or no effort.
Occupants feel clear tension against seat belts or shoulder straps. Unsecured objects are detached. Food service and walking are difficult.
Occupants are pushed violently against seat belts or shoulder straps. Unsecured objects are thrown back and forth. Catering and walking are impossible.
An aircraft is violently tossed back and forth and is practically impossible to control. May cause structural damage.
Most people experience only the lowest levels of turbulence, “light” and “moderate,” according to a survey of pilot reports.
“I’ve never experienced severe turbulence,” said Ms Smith. “It’s quite rare and a lot of pilots I know haven’t experienced it in their entire careers or only encounter it once or twice.”
Turbulence almost always feels worse than it is, and even official reports can be rather subjective.
“What some passengers have described to me as severe turbulence, thinking we were descending thousands of feet, was actually more moderate with maybe 10 feet of elevation gain and a few knots of airspeed variation,” Ms Smith said.
That said, unexpected turbulence does happen and injuries happen from time to time.
Of the seven million scheduled passenger flights last year, there were six serious injuries due to turbulence in the United States last year, according to data from the National Transportation Safety Board. So far in 2022 there have been eight episodes where someone was seriously injured.
Turbulence travel tips
“The one thing people should be afraid of due to turbulence is spilling their drink on a flight,” said Ms Smith. “Most turbulence injuries are caused by people not sitting in their seats or not wearing their seatbelts when things get bumpy. So keep your seatbelt on and don’t put your drink on your laptop!”
She has other tips for nervous fliers, such as sitting in the front where the ride is smoother, and flying in the morning. As the day warms into the afternoon, the heat rising off the land increases the likelihood of near-ground turbulence and storm-induced turbulence. She also has advice for younger passengers who may be scared and haven’t yet chosen their career path.
“It’s almost always a better ride in the cockpit than the rest of the plane,” Ms. Smith said. “So, if you don’t like the feeling of turbulence, become a pilot!”