In my near four decades of flying that exact route as a Qantas captain,I learnt there are particular challenges pilots face,especially at this time of year. It appears the Boeing 777-300ER aircraft in question struck severe turbulence entering the notorious Bay of Bengal,between the subcontinent of India and the Malaysian Peninsula.
This time of year,the Inter-tropic Convergence Zone,or ITZ,is very active. That’s a fancy aviation name for the monsoon,which we know simply as the “wet season” in northern Australia. Those ancient trade winds,which our international travelling forebears used to sail around the world,collide somewhere close to the equator. That collision line is the ITZ,and it moves north or south of the equator depending on the season.
When they meet,those opposing trade winds have to go somewhere,creating instability in the atmosphere that can translate into severe weather and turbulence,and a bumpy ride if you’re flying near them.
Current weather charts show a significant cloud mass right across the bay,with embedded thunderstorms up to 55,000 feet. Unless you’re flying the old Concorde – which used to cruise supersonic (faster than the speed of sound) at around 65,000 feet – you cannot fly above this weather. Current modern airlines simply don’t have that kind of “ceiling”,an aviation term for how high planes can fly.
So,as pilots,what tools do we have at our disposal at the pointy end of the plane to avoid the worst of such weather for the safety and comfort of those down back?
Pre-flight,we have very accurate weather forecasting showing these active areas of concern. This is backed up with satellite images confirming the worst areas. Armed with this knowledge,an airline’s dispatch – together with the pilots – will plot a course of least resistance through any known rough areas.
Once airborne,pilots have sophisticated weather radar at their disposal,plus other pilots flying the same route will broadcast bad weather and turbulence information in the area. Weather radar is designed specifically to help aircraft pick their way around this weather,or on some occasions through it.
I had a particularly bad squabble with turbulence while commanding an A380 flight from Los Angeles to Sydney some years ago. Just ahead of my flight was another Qantas A380 bound for Melbourne. It’s always nice to have a friend nearby. About an hour before the turbulence run-in,air traffic control relayed a message to us both about a “severe turbulence” encounter from an American aircraft just north of the Hawaiian Islands. This unforecast patch of turbulence was on both our routes and was caused by two jet streams colliding in the upper atmosphere.
After that communication between us and air traffic control,we ceased all meal services,battened down the hatches and made sure everyone had their seatbelts securely fastened,which was just as well as we had a wild ride for more than an hour. But no passengers were injured. Indeed,the only casualty was my second officer,who was on the flight deck with me. Tom had tried to retrieve his cap,which was bobbing unrestrained around the cockpit,when a severe jolt caused him to face plant against the centre console. He dislocated his shoulder.
If it gets that bumpy at the business end of a jumbo,you will understand how rough it can get further back. In a after a LATAM Airways flight hit turbulence in March between Sydney and Auckland,I used the analogy of a dog wagging its tail. The tip of the tail travels further than the other end,so an aeroplane is designed to wag its tail. The human body,unrestrained by a seatbelt,is not. That’s why they put first class up front,where the ride is smoothest.
This “wagging” and “flapping” is for structural integrity and load relief within the airframe. Just look at the wing tips “flapping” about in turbulence. Without that “wagging” and “flapping”,stress would be concentrated somewhere within the aircraft structure. Structural and metal fatigue would result,reducing the life and strength of the aircraft.
It’s easy to read headlines like the ones you are and ask:is flying becoming less safe? Is the atmosphere turbocharged by climate change? I can assure you that flying is still the safest form of transport. Not to sound unsympathetic – it’s a tragic incident and we mourn the loss of the passenger (who reportedly suffered a heart attack) and wish the injured a swift and complete recovery.
This will likely beget a debate over whether seatbelts on planes should be mandatory at all times other than during boarding and toilet breaks. I welcome the debate. In the meantime,the next time you’re flying and the pilots get on the blower shortly after take-off to advise you that,for your safety,at all times keep your seatbelt fastened,I recommend you listen to them.
David Evans was a Qantas pilot for 37 years.
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