Time to keep the seat belt sign on

That’s the key lesson from two airlines’ recent bouts with severe turbulence.

IF you are afraid of flying, your fear quotient must have shot up after the recent incidents of severe turbulence hitting two flights – Singapore Airlines SQ321 on May 21 and Qatar Airways QR017 on May 26 – resulting in one fatality and many injuries, some critical.

Aeroplanes suddenly dropping altitude is not new, but climate change has made the skies less friendly.

Climate change, especially global warming – or rather boiling, is creating more violent storms that uproot trees and blow off structures like billboards and roofs.

But in the air, storms are actually better for pilots, as they and their hi-tech equipment can detect the turbulence such weather can cause in advance.

As science writer Katherine Wright explains in a scientificamerican.com article, pilots can spot turbulence ahead of them relatively easily when they are flying inside a storm or among clouds. This is because onboard radar can track the movement of rain drops in the distance to reveal the turbulent motion of air.

“Pilots can then forewarn passengers and crew, encouraging them to take their seat and buckle up before a jolt hits,” she writes. “But turbulence in clear air, however, is invisible to radar; pilots typically don’t know it’s there until the plane hits it.”

That was what most likely happened on SQ321. It had cleared the Bay of Bengal, a region that some pilots regard as “notorious” this time of the year because its monsoon rains can cause turbulence. But as it was flying over Myanmar, cruising at 37,000 feet above the Irrawaddy River, it was hit by “sudden extreme turbulence” and the plane plunged 6,000 feet.

People were flung up and hit the cabin ceiling, oxygen masks fell out, overhead lockers burst open and anything not securely fastened went flying. As we know, one man died, said to be from a heart attack, and at least 70 people were injured.

At the time of writing, apart from reports that 12 people were injured, there is little information on the Qatar Airways incident that happened as the aircraft was flying into Dublin, its destination, from Doha. But it looks like another case of clear air turbulence.

In her nationalgeographic.com article, Michelle Z. Donahue defines turbulence as “chaotic and capricious eddies of air, disturbed from a calmer state by various forces” and illustrates it by adding, “If you’ve ever watched a placid thread of rising smoke break up into ever more disorganised swirls, you’ve witnessed turbulence.”

She adds that rough air can happen from ground level to far above cruising altitude, but the three most common causes of turbulence are mountains, jet streams and storms.

Air can form waves as it encounters mountains. Some can pass smoothly over or break into many tumultuous currents.

Jet streams are strong currents that circle the globe from west to east like rivers of air, and pilots like to fly within these bands to boost speeds and reduce travel times. But if two huge air masses close to each other move at different speeds, it can cause wind shear that can batter a plane’s wings, sometimes strong enough to jerk the plane up or down.

Turbulence created by thunderstorms seems like an obvious thing but a relatively new discovery by researchers is that storms can generate bumpy conditions in faraway skies. Donahue quotes Robert Sharman, a turbulence researcher at the National Center for Atmospheric Research, as saying “The rapid growth of storm clouds pushes air away, generating waves in the atmosphere that can break up into turbulence hundreds to even thousands of miles away.”

All of the above can cause “clear air turbulence” or CAT, the least predictable or observable type of disturbance. It can occur so suddenly, there is no time to warn the passengers to sit down and belt up.

Experts like Paul Williams, atmospheric science professor at the University of Reading in England, believe there was “strong evidence that turbulence is increasing because of climate change”, according to an Associated Press report.

Williams and his research team recently discovered that severe CAT in the North Atlantic has increased by 55% since 1979, and they have projected that severe turbulence in the jet streams could double or triple in the coming decades if global conditions continue as expected.

Most air travellers would have experienced some form of turbulence, be it the plane shaking or suddenly losing altitude. The majority of such occurrences are mild or moderate.

My own experience being on a plane that dropped like a rock was a flight from KL to Johor Baru more than 20 years ago. There was no warning when it happened. I remember lurching forward, but I didn’t become airborne because I was belted. There were screams of fright and the stewardess who was about to serve drinks dropped to a crouch position.

That was it. Fortunately, the drop wasn’t big enough to send things flying and overhead lockers opening, but I remember it to this day because of the split second of terror and the sickening feeling in the pit of my stomach.

All the experts say severe turbulence isn’t detrimental to aeroplanes, as they are built to withstand extreme stress and shocks. It’s just bad for the people inside because they are like peas in a tin can that is being shaken vigorously.

Since the SIA incident and now the Qatar one, the repeated advice is to keep one’s seat belt fastened. I think it’s time for airlines to stop informing passengers “the seat belt sign is now off” once the plane reaches its cruising altitude.

But in the SIA incident, people were also hurt as they were queuing to use the toilet, and those in the loos were said to be among the more critically injured victims.

Can something be done to make going to the toilet safer? Can the ceiling be somehow padded and have grab bars for a passenger to hold onto? These would be helpful even when there is no turbulence.

Aviation experts are also mulling over how to keep infants and small children safer on board, instead of allowing parents to hold them in their arms. Could child seats on planes become mandatory?

Another area that needs reviewing and strengthening are latches of the overhead lockers so that they do not burst open and spill out the contents on people’s heads in bad turbulence. The challenge is how to make them very strong and sturdy without making it difficult for passengers to open and close them. Aviation engineers, go figure!

To be fair, going by statistics, flying is still the safest way to travel, safer now than any time in the past. I take comfort in that. But I will also make sure that on my next flight, I do all I can to keep safe.

Since I will be in economy, I will follow advice to choose a seat near the wingspan in the centre of the plane so that I will be less likely to be affected by forces such as wind, drag and lift. I will limit my liquid intake to minimise visits to the loo, and you can bet your air miles, I will always belt up securely while seated.

The views expressed here are the writer’s own.