The injuries suffered by passengers and crew of recent Singapore Airlines and Qatar Airlines flights hit by turbulence are enough to unnerve air passengers.
But, pilots and safety experts say that, although turbulence is undoubtedly terrifying and the principal cause of injuries while flying – and may even be increasing – it is almost never a threat to aircraft remaining in the sky.
The issue has come into the public spotlight after 12 people were injured last Sunday when a Qatar Airways flight from Doha to Dublin was hit with turbulence and a 73-year-old British man died and seven people were critically injured on a flight from London to Singapore on May 21st.
Turbulence occurs when a plane flies into air disturbed by a range of factors, from atmospheric pressure, changing temperature and jet streams. It usually causes sudden sideways and vertical lurches in the plane’s trajectory. In mild and moderate forms, it can feel like a car driving into potholes.
In its severe and extreme forms, turbulence can cause passengers and crew to be thrown into the aircraft’s ceiling or dropped on the floor while trolleys can be flung about.
But experts say if that is happening, the plane is in the wrong place and something else has already gone wrong. Avoiding places where turbulence is likely is a day-to-day activity for all airlines. Planes regularly divert hundreds of miles to avoid thunderstorms.
A number of pilots and safety experts have said they cannot remember when a plane of a major airline, based in a well-regulated jurisdiction, has flown into a thunderstorm.
Nic Gammon, a first officer and qualified training instructor on Airbus 330 aircraft who flies transatlantic routes for Aer Lingus, said there were places where turbulence can be expected – over the Alps and in the tropics, for example.
As standard practice, planes have the technology to detect adverse weather more than 160km out. They also have weather forecast charts prepared before they fly and can rely on the network of other planes all around them to report any adverse conditions, Mr Gammon said.
He said turbulence may “feel like free falling but in my experience of crossing the Atlantic turbulence might make a plane drop 20 to 50ft before being corrected”, he said.
Turbulence is “an annoyance” and “frustrating”, but he said the “wings don’t fall off”, he said.
Even a plane being struck by lightning usually has no serious consequences, he said.
“A lightning strike is not as calamitous as it sounds,” he said, pointing out that planes are built so passengers are insulated from the strike and thin rods from the wings help dissipate static electricity.
Earlier this year, an Air Canada Boeing 777 was struck by lightning as it departed from Vancouver, British Columbia. For nervous passengers it would be the ultimate nightmare scenario, but there were no issues with the flight and it continued on its journey to London, England, where it landed safely. A video of the event online has garnered more than a million views since being posted in March.
Mr Gammon said when a plane encounters unavoidable light to moderate turbulence it is more of an irritation than a danger to the aircraft.
He recalls a flight from Orlando in the United States to Dublin that encountered turbulence all the way. He said if the plane is very heavy, it may not be an option to fly through turbulent conditions, while going lower could use more fuel and pose a threat to the plane reaching its destination.
“You just have to endure it,” he said.
However, when a plane encounters severe or extreme turbulence something else has already gone awry, according to pilot John Leahy.
Mr Leahy, a former chief pilot on British Airway’s 747 fleet and a former director of safety at Ryanair, said that if passengers were flung about, hitting the roof of the plane and then the floor, it was likely other mistakes were already made.
“I cannot – and most pilots could not – remember when a plane from a major carrier in a well-regulated jurisdiction last encountered severe turbulence leading to the kind of injuries reported on the Singapore Airways flight,” he said.
He said injuries that happened on board planes could be very severe and safety precautions, such as avoidance and seat belt wearing, were always taken by the airline and the passenger respectively.
He said that in 2022 there were between four and five billion passenger trips of commercial aviation and “not one person died that year”.
“There are few activities as safe as flying. You could not be safer than in a plane,” he said.
Mr Leahy said information was still emerging about the turbulence that affected the Qatar flight to to Dublin.
“But the question I would be asking is why the ‘fasten seat belt’ lights were switched on only immediately before the incident,” he said.
He said questions remained about why the plane was involved in such turbulence when the plane’s radar could have detected it in advance.
“Even though you do have these incidents, they rarely end in tragedy,” he said.
Experts have also questioned the initial reporting of the Qatar incident, particularly reports that the plane fell 275ft at a rate of 21,888 feet per minute. Mr Leahy and others pointed out that the fatal Air France flight 447, from Brazil to France in 2009, descended at 11,000ft per minute, an unrecoverable trajectory. In the Air France case an investigation concluded inconsistent airspeed indications led to the pilots inadvertently stalling the Airbus A330.
Studies on the incidence and effect of turbulence in the context of climate change have been carried out by the University of Reading in the UK. Research published by the university last year showed that clear-air turbulence, which isn’t connected to any visual clues such as storms or clouds, had increased in various regions around the world.
At a typical point over the North Atlantic – one of the world’s busiest flight routes – the total annual duration of severe turbulence increased by 55 per cent, from 17.7 hours in 1979 to 27.4 hours in 2020, the research found. Moderate turbulence increased by 37 per cent from 70.0 hours to 96.1 hours, and light turbulence increased by 17 per cent from 466.5 hours to 546.8 hours.
Prof Paul Williams, an atmospheric scientist at the university who co-authored the study, said investment should be made in improved turbulence forecasting and detection system to prevent the rougher air from translating into bumpier flights in the coming decades.
“Planes are not going to start falling out of the sky, because aircraft are built to very high specification and they can withstand the worst turbulence they can ever expect to encounter, even in the future,” says Williams.
But he said the average duration of turbulence will increase.
“Typically, on a transatlantic flight, you might expect 10 minutes of turbulence. I think that in a few decades this may increase to 20 minutes or to half an hour. The seat belt sign will be switched on a lot more, unfortunately for passengers,” he said.
The Irish Aviation Authority said there was one accident due to an aircraft’s encounter with turbulence and no serious incidents between 2018 and 2022.
A spokesman said that there were no turbulence-related accidents or serious incidents involving Irish commercial aircraft last year.
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