Twelve passengers and crew were injured when a Qatar Airways flight encountered turbulence over Turkey. The flight from Doha to Dublin landed safely after a passenger was “struck by the roof” of the plane.
It comes just five days after a Singapore Airlines plane encountered sudden turbulence over Myanmar and descended rapidly, killing one British passenger and injuring 104.
Turbulence is common during flights, but are some routes more prone to it than others, and which routes experience the most turbulence?
What is turbulence?
Turbulence can be felt when a plane flies through relatively turbulent air and causes “sudden side-to-side or vertical shaking” during flight, according to the Australian Civil Aviation Safety Bureau. Turbulence is a leading cause of in-flight injuries to crew and passengers.
The agency defines eight types of turbulence, including thunderstorms, thermals, fronts and mountain waves, and classifies them into six categories of severity.
Where does turbulence occur most often?
Turbulence typically occurs over high mountains, oceans, the equator and when the jet stream approaches, said Dr Guido Karim Jr., director of Griffith Aviation at Griffith University, but clear air turbulence is usually caused by sudden changes in wind direction and can occur anywhere, anytime.
“There are a lot of very complex factors interacting to create turbulence,” the former pilot said, adding that even a forest fire could cause it. “Radar technology to detect turbulence is improving, but despite all the instrumentation on board, we still can’t predict exactly when and where turbulence will occur.”
He has flown international routes over the Andes, where it is mandatory to turn on the seat belt signs as the plane approaches the mountains.
The Bay of Bengal during monsoon season is notoriously turbulent, as is flying over the Alps, “but sometimes you don’t even notice,” he said.
High humidity and temperatures tend to increase turbulence, so flying from London to New York City in summer can be more bumpy than flying the same route in December, he said.
What are the most turbulent flight routes in the world?
Swedish turbulence forecasting site Turbli uses data from the US National Oceanic and Atmospheric Administration and the UK Met Office to record turbulence.
The routes with the most disruption in 2023 were Santiago, Chile to Santa Cruz, Bolivia; Almaty, Kazakhstan to Bishkek, Kyrgyzstan; Lanzhou, China to Chengdu, China; Centrair, Japan to Sendai, Japan; and Milan, Italy to Geneva, Switzerland. Milan to Zurich, Switzerland ranked 10th.
The site said the roughest countries it flew over in April were French Polynesia, Fiji, Pakistan, Namibia and Uruguay, while the roughest waters it flew over that same month were the South Pacific.
Mild turbulence No turbulence was recorded above an eddy dissipation rate (edr) of 20. Severe turbulence occurs above 80edr.
According to statistics from the Australian Transport Safety Bureau (ATSB), there were 3,047 commercial aircraft accidents worldwide in 2023, of which 236 were caused by weather.
To date, there have been 790 commercial airline accidents in 2024, of which 52 were caused by weather.
Are the Qatar Airways and Singapore Airlines crashes related?
Milton Spear, a meteorologist and researcher at the University of Technology Sydney, said if the two planes encountered turbulence in the same area they could be affected by the same weather conditions, but flights QF17 and SQ321 were thousands of kilometres apart when they encountered severe turbulence.
Karim Jr. said he saw no obvious atmospheric or weather phenomena associated with the two turbulence episodes this week, and that he had spoken to pilots who had flown in both areas recently and were told they “didn’t see anything unusual.”
But we do know that the number of severe turbulence incidents is on the rise — up 55% between 1979 and 2020 — and that climate change is thought to be the cause.
How many turbulences have there been in Australia?
Turbulence events only need to be reported to the ATSB if they affect the performance of an aircraft. In the 10-year period between 2014 and 2023, no events resulting in serious injury to passengers have been reported to the ATSB, the spokesman confirmed.
“We advise passengers to keep their seat belts fastened during all flights, whether or not the seat belt sign is on,” a spokesman for the Air Pilots’ Association of Australia said. Civil aviation regulations state that all crew and passengers must wear seat belts in a range of situations, including when the aircraft is flying below 1,000 feet.