Reasons Behind Increased Turbulence on Certain Flight Routes

Turbulence during flights isn't a new phenomenon, but recent incidents have fueled concerns, especially after two severe turbulence events occurred in quick succession.

The first alarming incident happened on May 21 on Singapore Airlines flight 321 traveling from London to Singapore, where a passenger sadly lost their life (reportedly from a heart attack) and many others sustained injuries. Shortly after, Qatar Airways flight 107 from Doha to Dublin encountered turbulence so severe that 12 individuals had to be hospitalized for treatment. Investigations into both occurrences are currently ongoing.

These events have heightened worries that as climate change leads to more extreme weather, the likelihood of harrowing experiences at high altitudes may also increase.

However, there are encouraging signs for improved in-flight safety: A recent bill reauthorizing the Federal Aviation Administration (FAA), which has passed Congress and received presidential approval, includes a key provision that mandates the agency to implement a series of safety measures aimed at reducing injury rates. These recommendations, stemming from a 2021 report by the National Transportation Safety Board (NTSB), involve better weather data coordination and promoting the use of child safety seats.

The NTSB report indicated that “accidents caused by turbulence are the most frequent type of incident” involving U.S. airlines in recent years, often leading to one or more serious injuries.

The NTSB suggested that advancements in technology and improved monitoring could assist pilots in avoiding the most severe weather conditions.

“We’ve become more adept at forecasting these events,” remarked John Cox, a veteran pilot and president of Safety Operating Systems, a consultancy specializing in aviation safety.

He pointed out that while enhanced technology for pilot alerts can be beneficial, some of the best safety measures are quite simple: Aviation experts have consistently recommended that passengers keep their seatbelts fastened at all times while seated, even when the seatbelt sign is off.

In addition to this practical advice, are there other steps travelers can take to shield themselves from—or even steer clear of—a turbulent flight?

Are certain flight paths more susceptible to turbulence than others?

Turbulence can occur anywhere and at any moment, particularly “clear-air” turbulence, which, as the name implies, often appears suddenly and without warning. The frequency of clear-air turbulence is increasing, influenced by climate change's impact on jet streams—powerful wind bands that generally flow from west to east around the globe. There are four primary jet streams on Earth: two polar ones near the North and South Poles, and two subtropical ones closer to the equator.

Safety expert Cox noted that some regions are more likely to experience turbulence, particularly flight routes over the North Pacific and North Atlantic, as well as mountainous regions like the Andes, Alps, Himalayas, and Rockies. Another turbulence hotspot is the intertropical convergence zone near the equator, where the trade winds from both hemispheres meet, creating a band of low pressure and clouds.

In terms of specific flight paths, Turbli, a turbulence forecasting company, has created a list of routes most likely to encounter turbulence, drawing on data from the National Oceanic and Atmospheric Administration and the UK’s Met Office.

Over the past two years, the most turbulent flight recorded was the one between Santiago, Chile, and Santa Cruz, Bolivia—this isn’t surprising, as the route travels directly over the Andes mountain range.

The most turbulent flight paths in the world

As reported by turbulence forecasting company Turbli, here are the top 10 most turbulent flight routes globally:

In the United States, the route from Nashville to Raleigh/Durham ranks as the most turbulent, followed closely by the flight from Charlotte to Pittsburgh.

However, not all pilots find these rankings meaningful. Patrick Smith, a U.S. airline pilot and author of the “Ask the Pilot” blog, deems the lists “silly” since “9 times out of 10, flights on these routes are smooth and uneventful.”

Are there specific times during a flight when turbulence is more likely to occur?

Singapore Airlines flight 321 encountered severe turbulence at approximately 37,000 feet, causing the aircraft to drop 178 feet in less than a second. However, this is not typical, as noted by the NTSB report, which found that between 2009 and 2018, nearly half of turbulence-related incidents on commercial flights occurred during descent or approach, with 60 percent happening below 20,000 feet.

Does the aircraft type play a role, and is there a specific area within the plane that offers more safety?

According to NTSB data, smaller planes are more susceptible to turbulence. Within the aircraft, injuries from turbulence are most common in the rear section, where over three-quarters of injuries sustained by flight attendants occur. Flight attendants face the highest risk on board since they spend significant time on their feet. The NTSB recommends that flight attendants remain seated with their seatbelts fastened during more phases of descent to help minimize injuries.

Although both planes involved in the recent incidents were Boeing models, there is no indication that any specific large aircraft model is particularly prone to turbulence.

Should child safety seats be mandatory for children under 2 years old?

The consensus among the NTSB and the safety community is a resounding yes on the necessity of child seats for infants and toddlers under 2, rather than allowing them to sit as “lap children” with their caregivers. However, this remains merely a recommendation for now, and parents can still choose to hold a child under 2 on their lap without purchasing an extra seat.

How frequently does turbulence occur, and what are the best measures to safeguard against it?

Severe turbulence remains a rarity, as do the serious injuries it can cause: the NTSB reported 163 turbulence-related injuries in the United States from 2009 to 2022, with 129 of those involving crew members.

In the end, the most effective protection for all passengers against unexpected severe or extreme turbulence is the same as it has always been: keeping seat belts fastened while seated. Recent incidents reinforce this advice, as most of the injured were not wearing seat belts or were flight attendants required to move around the cabin. Consequently, one of the first changes Singapore Airlines implemented after its recent troubling flight was to revise its in-flight seat belt sign policies, especially during meal service.