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At least 12 passengers on a Qatar Airways flight from Doha to Ireland reportedly sustained injuries due to turbulence on Sunday, May 26.
The incident comes just five days after a Singapore Airlines flight from London to Singapore was diverted to Bangkok due to severe turbulence, which caused the aircraft to drop 6,000 feet in five minutes. The turbulence on that flight resulted in the death of a 73-year-old British man, with 20 other passengers requiring intensive care.
Turbulence-related airline accidents are the most common type, according to a 2021 study by the US National Transportation Safety Board. The agency found that from 2009 through 2018, turbulence accounted for more than a third of reported airline accidents. Most incidents resulted in one or more serious injuries but did not cause aircraft damage.
What causes turbulence?
Turbulence, much like choppy waves at sea, is caused by pockets of turbulence in the air. It arises from three primary sources: thermal (warm air rising through cooler air), mechanical (airflow disrupted by mountains or manmade structures), and shear (air pockets moving in different directions).
This turbulence can make an aircraft rise, fall, and rock from side to side.
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Experts believe that most turbulence occurs within clouds due to updrafts and downdrafts of wind. While much of this turbulence is mild, larger clouds, like cumulonimbus thunderstorm clouds, can cause moderate to severe turbulence.
Then there is the ‘clean-air turbulence’. The US Federal Aviation Administration (FAA) describes clear-air turbulence (CAT) as sudden and severe turbulence in cloudless regions, causing violent aircraft buffeting (repeated heavy blows).
What triggers clear-air turbulence?
Clear-air turbulence, as its name implies, occurs in cloudless and invisible conditions, making it particularly difficult to detect. This type of turbulence often occurs around the jet stream, a fast-flowing ‘river’ of air typically found at 40,000-60,000 feet.
The speed difference between the jet stream air and the surrounding air, which can be as much as 100 mph, creates friction that leads to turbulence. This turbulence is ever-present and shifting, making it challenging to avoid.
CAT is particularly challenging because it often occurs unexpectedly and without visual warnings for pilots.
Each year, thousands of aircraft experience significant turbulence, reportedly resulting in up to $1 billion in costs for the aviation industry due to flight delays and structural damage.
How dangerous is mid-air turbulence?
Aircraft are engineered to withstand severe turbulence, say aviation experts. It is ‘unlikely’ for turbulence to severely damage an aircraft. However, turbulence can still pose risks to an aircraft, prompting pilots to avoid it by reducing speed, adjusting altitude, activating the seatbelt sign and sometimes changing flight path as well.
Experts indicate that in extreme cases, turbulence can cause structural damage due to strong winds. Severe turbulence can be dangerous for passengers, causing violent movements that may throw unbelted individuals across the cabin.
Despite this, aviation safety experts point out that fatalities and injuries from turbulence are rare. However, it is important to note that injuries from severe turbulence are ‘relatively rare’ given the millions of flights operated. According to the US National Transportation Safety Board, there were 163 ‘serious turbulence injuries’ on US airlines from 2009 to 2022, averaging about 12 per year.
What role is global warming playing in increased turbulence?
Some researchers believe that climate change has increased the likelihood of turbulence. Last year, scientists from the University of Reading in the UK reported that severe turbulence had risen by 55 per cent between 1979 and 2020 on a frequently used North Atlantic route. They attributed this increase to changes in high-altitude wind speeds caused by warmer air from carbon emissions.
This finding aligns with predictions by researchers at the University of Chicago, who forecast that rising temperatures could increase wind speeds in the ‘fastest upper-level jet stream’.
Their study indicates that wind speeds will rise by 2 per cent for every degree Celsius of global warming, which could reach an increase of 4 degrees Celsius by the century's end if greenhouse gas emissions continue to rise.
Global temperatures have already increased by at least 1.1 degrees Celsius since the pre-industrial era, with the most significant rise occurring since 1975, according to US space agency NASA.
Experts also suggest that increased turbulence encounters are partly due to the higher volume of flights. Busier skies are making it more challenging for pilots to avoid turbulence while maintaining a safe distance from other aircraft.
How do pilots manage turbulence?
Before flying, pilots receive detailed aviation forecasts that include meteorological data. They use this information to plan their routes, helping them avoid isolated thunderstorms.
However, ‘clear air’ turbulence is more challenging to predict. Pilots rely on reports from other aircraft on the same routes about any encountered turbulence. They aim to avoid these areas or slow down the plane to minimise turbulence impact. Crews are trained to respond effectively to turbulence.
What can passengers do to stay safe?
Passengers are advised to keep their seatbelts fastened and avoid having heavy objects out. Pilots recommend that passengers stay strapped in at all times due to the unpredictable nature of turbulence.
