Faster and safer flight

The plane shudders violently, your seat seems to fall below you and, if you're not attached to the interior, you can quickly find yourself with your meal tray flying towards the ceiling of the cabin.

According to the best estimates, the severe injuries associated with turbulence represent 7,000 workdays lost for flight attendants and turbulence costs the industry hundreds of millions of pounds a year. And, sometimes, it can be deadly. On smaller planes, it is responsible for the deaths of about 40 people each year in the United States alone.

S tackle the problem of turbulence

Thanks to the work of Paul Williams, professor of atmospheric science at the University of Reading, airlines have a smarter way to avoid disruptive turbulence at mid-flight. With colleagues from the United States and with the support of NERC, he developed a forecasting system that allows for better prediction of turbulence zones in advance, allowing pilots to redirect their flights to smoother routes. and safer.

"Turbulence is the leading cause of injury to air passengers and flight attendants, and since our forecast model was adopted by US authorities in 2015, we believe this has contributed to improved comfort and safety for flights up to 2.5 billion trips. "

Although there are many forms of turbulence, some are more troublesome than others. A common form, called convective turbulence, occurs in and around thunderstorms. Powerful updrafts at the heart of a storm can push planes up or down more than 100 feet. Fortunately, thunderstorms appear on the radar and can be spotted by the human eye, which makes it relatively easy to avoid.

Avoid the invisible

Turbulence in clear air, which is invisible and often hits without warning, is much more difficult for pilots.

Paul says, "It comes out of nowhere, literally, all those who have flown a few times will have flew over it.It is the kind of person who can hurt people if they do not wear seatbelts. . "

In May 2017, 27 people were injured when Aeroflot SU270 was hit by turbulence as it prepared to land in Bangkok. Some passengers fractured when the plane dropped and were thrown to the ceiling. Violent eddies can also damage aircraft. In December 1992, a plane struck a clear turbulence zone over Colorado, which tore six meters off its left wing and pulled out one of its four engines.

The turbulence of clear air is usually at relatively high altitudes, usually above 20,000 feet. It is also closely related to jet streams, narrow and fast airbands that cross the atmosphere several kilometers above the ground.

The jet stream boundaries, where the fast air corridor meets the slower air circulation that surrounds it, are unstable and chaotic and scatter powerful whirlwinds of wind into the atmosphere. surrounding. If a plane flies over one of these swirls, the rapid movement of air will freeze its wings, causing it to lose or gain altitude.

Surf the gravity wave

However, the stream stream represents only part of the image. During the Ph.D. funded by Paul NERC at Oxford University in the early 2000s, he studied the role of gravity waves in creating turbulence in the clear.

Atmospheric gravitational waves are formed when the air is disturbed, for example by being forced to climb a mountain range or a weather front. Fragments of air then move like waves in the sea when gravity waves cross the sky. The atmosphere is full and can sometimes be seen as striped clouds or large ripples on the surface of an ocean. If a jet stream alone is not enough to release turbulence in the clear, the addition of powerful gravity waves in the same region of the atmosphere can do the trick.

Paul developed a practical forecasting tool for clear air turbulence that was adopted by the US authorities in 2015. The model takes 18 hours to predict the likely behavior of the jet stream. He then uses an equation to reveal where gravity waves are generated and where clear air turbulence is most likely to occur. If there is a moderate turbulence affecting the aviation, the algorithm predicts it successfully in 83% of the cases.

The model predicts all the forces of turbulence in the clear, lighter forms that cause tremors and shaking, with rare but potentially dangerous shapes, which could cause injury to the crew and passengers, or damage to the aircraft. 'aircraft. But in addition to reducing injuries and damage, there is another benefit. Turbulence is the underlying cause of the fear of stealing from many people – a phobia that affects up to four in ten people.

Paul hopes that this model, freely available to all, will be adopted around the world. However, as aviation security is tightly regulated, changes will not be immediate. The model will become increasingly important in the future as Paul has also shown that clear turbulence is likely to be more common as the world continues to heat up. He predicts that the amount of turbulence in the jet streams will have doubled or tripled by 2050-2080.

He said: "If this is the future of the flight, it will be even more important to give planes the chance to avoid potentially damaging turbulence."

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