Menu lock


Oct 8, 2017

Turbulence could be making a more serious comeback in air travel

If as this study suggests, high smooth levels of the atmosphere are becoming more turbulence prone, air travel will have a new barrier to tame

Ben Sandilands — Editor of Plane Talking

Ben Sandilands

Editor of Plane Talking

Cirrus clouds may give clues to risks of clear air turbulence

One of the worst things about flying before the jet age began on a large scale in the late 50s was turbulence, causing air sickness.

But there are warnings, as well as some statistical claims, that things are getting rougher than before for the smoothness of jet airliners that has long been taken for granted by generations of air travellers.

This week’s ‘return to your seat and buckle up’ contribution to the genre comes from America’s ABC. It is based on this article in Geophysical Research Letters, and as is often the case, the general news story has a high tease to factual content ratio that makes it perhaps less than useful to the curious who want to know what it is really about and how it might affect them.

It’s an analysis as to how increased upper atmosphere turbulence attributable to climate change is potentially lifting the risk of clear air turbulence, or CAT, which first came to the attention of the mass of air travellers with the shift to faster, higher flying jets because they flew where the propeller driven aircraft of old couldn’t venture.

The days of a Lockheed Electra or Vickers Viscount being full of passengers chundering into airsick bags while bouncing around for more than an hour below or right in the middle of clouds between Sydney and Melbourne were replaced by the velvet like ride of higher reaching 727s.

However at infrequent intervals, something like the CAT’s ‘claws’, as headline writers liked describe them, would strike with zero warning where the 707s and DC-8s and Comet IVs went, far above the bumpy flight levels below at around 26,000 feet. CAT can strike with enough violence to punch unrestrained passenger heads through ceiling panels, and break arms and legs. The ‘attack’ was often over in seconds, but the results could be devastating, and the certification strength and resilience of airframe components were raised to levels in later designs to where the risk of severe structural damage was much less likely.

But these events continue to happen, and according to the study, with rising frequency, and come with do-not-exceed rules that mean compulsory component inspections and any necessary repairs or replacements are required when the load or gust data recorded during a flight crosses the limits imposed by the regulations.

Recent generations of regular flyers have withstood these events with less damage to themselves by taking to heart the admonition to keep seat belts loosely fastened even when the warning sign is off.

Which means this is an emerging issue of concern. It is not like the other more common forms of in-flight turbulence that have been ameliorated by the active gust alleviation systems that all the latest Airbuses and Boeings use to smooth out the type of bumps that can be detected or predicted by on-board sensors and massaged away by rapid changes to ailerons, elevators and rudders.

Those fast and frequent systems driven adjustments to these control surfaces soften, confine or even eliminate the up, down and sideways jerkiness that can sometimes intrude on a flight. But if this study highlighted in the general media recently is correct, the CAT’s claws will become much more of a problem, not just because more people are flying more often, but because of more pent up heat energy destabilising the higher flight levels their jets are using.

We recommend

From around the web

Powered by Taboola


Leave a comment

39 thoughts on “Turbulence could be making a more serious comeback in air travel

  1. nonscenic

    There is likely a mixture of reasons why jet travel is getting bumpier. As the paper indicates global warming is leading to stronger thermal gradients between low and high latitudes with consequent stronger jet streams and more frequent CAT. Other factors (besides the overall growth in number of vulnerable flights might include the greater number of long haul flights with less ability to avoid tropical thunderstorm regions with wide margins either because of fuel endurance or more congested flight paths.

  2. Jacob HSR

    What about the high altitudes that Concorde flew at? A stupidly named firm, Boom, is going to fly supersonic in 2018. I wonder if there is more turbulence at that altitude compared to 30,000 feet.

  3. comet

    Any mention of climate change will inevitably bring out the climate-change-denying whackos who’ll write essays and screeds of text overflowing with nonsense and blether.

  4. Tango

    Call me the odd man out, but having flown in aircart since I was age 3, we learned to buckled up (actually it was not a choice).

    My dad had seat belts put in a Carryall before they were required.

    WE wore life vests when we were on a boat.

    I have continue3d those early lessons, I never did stop buckling up on an aircraft.

    If I am in my seat in an aircraft, I am buckled in. While not common, rising up in mid air and having your head beat against a celling and then dropped down over arm rests and seat backs never seemed like a good idea.

  5. Deano DD

    Is it just me or does any one else feel a bit let down if the flight is silky smooth
    Can’t beat a bit of roller coaster action on a stormy afternoon in the tropics

    1. Dan Dair

      Will you be cross with me if, from now on, I think of you as a bit strange.???

      1. Dan Dair

        that’s a bit like saying I don’t feel like washing-day is going properly,
        unless I’ve been chased around the room a bit by my washing machine on its spin-cycle.?

        1. Tango

          Well it certainly lends excitement to an otherwise kind of boring activity doesn’t it?

          Granted, I preferred it when my wife was chasing me around the house but I am not nearly as young as I was, a washer chasing me might be just up my ally these days.

          Seaking of which, many years ago my wife killed our Washer, we got a set of Payer Pakel (sp?) machines.

          Love em, never had machines that were so easy to work on.

          12 years old and still going strong.

          First in the US that spun so fast that the cloths were damned near dry when they came out.

          Now that is an energy savings, less gas (up here) and often we can line dry easily.

          1. michael r james

            Tango wrote:
            “12 years old and still going strong. First in the US that spun so fast that the cloths were damned near dry when they came out.”

            That ain’t nuttin. I bought a second-hand Miele combined washer-dryer in my first year in Paris (1984) and only finally disposed of it a few months ago (it still worked)–it has lived in France, UK and Oz, and I reckon it must have been close to 40 yrs old (better travelled and older than some people reading this post! hmm no, wrong audience …:-). It was one of those models you don’t see elsewhere because it is designed to fit in a very narrow kitchen slot (it is a horizontal drum but a narrow sideways one which you load from the top via a special drum-door!) as you need in some Euro cities. Miele and the Germans built their machines to spin clothes almost dry for the same reason (apartment living). Its main downside was that it weighed as much as a small car.

  6. Goat Guy

    I’d suggest people read the full paper and in particular the “Methodology” section. Seems the control group was a model run using “pre-industrial revolution” CO2 levels vs the CIMP 5 models for the period 2050-2080. I’m always curious when people use model vs model and not actual vs model. Would have been nice to see them run a model for the last 10 years and compare it to actuals to ensure they had their calcs right.

  7. JW (aka James Wilson)

    “Recent generations of regular flyers have withstood these events with less damage to themselves by taking to heart the admonition to keep seat belts loosely fastened even when the warning sign is off.”

    I never cease to be amazed at the number of passengers who choose to ignore that warning and also choose to ignore the seat belt signs when they are on. Idiots.

    1. michael r james

      Just last night on SBS news they showed spectacular CCTV footage inside one of those big long-distance coaches in China. Some idiot car driver tried to occupy the same road space and caused the bus to roll. The only pax injured were the relatively few who weren’t wearing their seat belts (yes, seat belts on Chinese buses, who knew? reminds me of my youth on crazy buses on the Thai highways ….).

  8. Rais

    I wonder if the amount of turbulence passengers have to endure varies depending on whether you’re on a low cost airline or a full service one? On a flight home from Jakarta to Perth with Garuda when there was a major cyclone near Port Hedland the pilot informed us after takeoff that there might be “a little turbulence” during the flight. We took off and relaxed then after about an hour my wife looked out the window and told me we were still over land. I checked the flight track on the screen and saw that instead of flying southeast from Jakarta the pilot had flown east along the north coast of Java a thousand odd kilometres and only now was turning southeast. We proceeded across inland WA waay east of the cyclone with hardly a bump but Garuda must have been prepared to pay a much bigger fuel bill to do that. We concluded that the extra money for Garuda over an Air Asia Indonesia ticket had probably been worth it.

  9. Zipper

    Here we go again, the good old climate models, trying to predict something 30 years plus away, another scare mongering excercise, let’s all gather round and accept it as gospel, and I thought it was called climate change now not global warming considering average world temps have barely moved, 0.8 celcuis since 1800, since the mini ice age the world will gradually get warmer and will continue to do so for the next 2-300 years, but not at the ridiculous levels these so called models predict, they can’t even predict what the weather will be like next week never mind 50yrs away! Absolute garbage these climate models..

    1. Rais

      “I thought it was called climate change now not global warming…” This pointless quibble gets my goat. It’s called climate change now because the deniers who objected to the term global warming insisted on calling it that. No other reason. Climate change science identifies a global warming trend and most of the hottest years recorded have occurred since the year 2000. How it works is simple physics, no PhD required. As for the confusion between predicting the weather a week ahead and identifying a long term climatic trend, there is nothing in common between the two processes. Even if the average temperature of the world rose by a degree in the next 20 years there would still be some cold weather in winter though less, on average, than we have now, and a number of days in summer would be below the present average temperature though it would mostly be hotter.

  10. George Glass

    Yeah,Comet. All us crazy guys with science degrees that actually understand the physics of global warming.Can you explain how a toilet works? Thought not.But you are absolutely certain that global warming is the greatest moral challenge of our time. Why? What is the theoretical basis for more turbulence in jet streams, that occur at altitudes above 26000 feet at the bound between polar,Ferrel and Hadley cell circulation , at below minus 30 degrees centigrade.Precisely how would an increase of 2 degrees C at sea level cause this to happen? I had a great ride in a 180 knot jet steam going Perth – Sydney the other day.Home an hour early.Not a ripple.All jet Pilots manage jet steams on a daily basis.Its what we do. Its routine.Just more climate change hysteria.By scientists who want more funding for climate change “research”.

    1. Ben Sandilands

      I don’t think the airline industry is going to be diverted from the immediate issue of more high altitude clear air turbulence if that’s what the stats, adjusted for growth in flying at those levels, tells us. This is at its core, about a prediction that damaging incidents will increase. It shouldn’t be beyond the capacity of technological improvement to devise new ways of seeing what the state of clear air is in front of an airliner in order to prevent some really nasty sh*t happening.

      1. Zipper

        That’s right Ben, it’s just a prediction, nothing more, like all the climate models going around now, just predictions, doesn’t mean it’ll happen, unfortunately all the hipster lefties lap this stuff up, puting pressure on Govts to spend billions of our money on things to prevent something happening that they have zero proof that it will happen! It’s easy to say the climate will be a mess in 100yrs time because none of us will be around to prove it wrong.. the single biggest issue in the world today is not climate change, it’s over population, but that’s not a cool thing to talk about while you eat your smashed Avo on toast..

        1. Ben Sandilands

          Talk is cheap. Governments aren’t spending billions on climate change related measures, nor even considering articulate plans for such action in this country or its states. What I think is happening is that without necessarily having much involvement in the arguments about the science, consumers and businesses are shifting spending to products or services that exploit renewable sources of energy, or consume energy more efficiently, because it saves money. The trajectory of better battery storage for less ought to be obvious, and it is already destroying the longer term investment case for poles and wires for example. NSW would never get the $24 billion or thereabouts it made out of half of its key distribution networks in say five years time. Coal burning power stations have to make money over a 40-50 year period. No-one can guarantee that in the 21st century. But typical renewable investments can get faster to market, and be fully depreciated and replaceable in 10 years time, if not upgradable along the way. Its hard dollars that are doing in coal, and a lot of the popular media jumping up and down caused by climate science debate is just static or an opportunity for social media jousting by the opposing camps. In case you are in any doubt, I think mankind has made climate variability subordinate to damaging global warming, with widespread unintended consequences such as the destruction of the marine food chain through the acidification of the oceans. I don’t walk down the street picking fights about this with those who reject the science, because the debate will be won, perhaps too late to avoid some very undesirable consequences for our species, by the superior affordability and rising level of utility of energy tech that doesn’t depend on the excessive release of fossil locked carbon. I won’t be here to see it happen, but I hope my descendants, and yours, will benefit from better, cleaner, ways of tapping into energy.

          1. George Glass

            Fact;increasing CO2 partial pressure in the atmosphere will cause an increase in average temperature.
            Fact;according to Beers Law, the absorption of long wave radiation re-radiated from the earths surface by each partial pressure of gas is logarithmic.CO2 will absorb a fraction of the spectrum not already absorbed by the most important greenhouse gas,water vapour and the rest of the atmosphere.
            Fact;the consequence of the above is that the increase in temperature due to the increase in CO2 will max out at about 450 ppm,or around 2 degrees centigrade.There will not be run-away global warming.The IPCC documents themselves hypothesize that further warming will be due to increased average humidity and secondary increase in other green house gases,mainly methane.
            Fact;In geological terms, the most fecund and prolific periods in biological history have been warmer and with higher CO2 levels.
            Fact;most of the febrile arguments over global warming are ill-informed drivel and hysteria devoid of considered argument or scientific rigor over-laid by fear and ideological prejudice.
            Fact;no need to have an existential panic Ben.We will learn to live with it.

          2. Dan Dair

            Of course we’ll learn to live with it.
            Most of us will have seen dystopian futures in sci-fi movies, where the air is barely breathable & clean-air too expensive for all but the wealthy, or where acid rain or excessive UV makes it virtually impossible to exist outdoors for any length of time.?

            I don’t KNOW that climate change is real, just the same as I don’t KNOW when the oil will run-out, but I’m reasonably confident that both will happen.
            And if we do nothing about them,
            the day after either is formally confirmed,
            life as we currently know it will be over.?

            Or we can choose to do nothing about it, because some powerful groups have deluged the media with false & partially-true stories
            & by the time the full story comes out,
            it may well be too late to do anything to change the situation we might have got ourselves into by then.?

      2. Goat Guy

        The paper doesn’t look at stats. It compares the outputs from models. It might well be that clear air turbulence will increase and that the CIMP 5 model and calcs they use are amazingly accurate for telling us what will happen from 2050 to 2080 but it would have been nice to see them run their model and calcs for the last 10 years and compare that to actual data so there was a level of confidence in their methodology.

        1. Ben Sandilands

          That’s close to how I hoped readers would engage with the post. My starting point is that everyone will click on the hyperlinks and consider the source material.

  11. Tango

    While the good old Zipper is right about predictions, the reality is that they can be low as well as high (it could be worse).

    And having followed the history, we are in a serious warming trend.

    Climate change is real, argue all you want about the cause, its a reality.

    Deny it all you want, its getting warmer, things change and it may be for the worse, more so in low lying areas like Cities on the Ocean and Islands that are barely above water now.

    And regardless, you should always wear your seat belt when seated on an aircraft and in your car.

    Not because some law or sign tell you to, its the smart thing to do.

    1. Ben Sandilands

      There was a time, not long ago, when ‘we’ could clear land in the forest and take what we wanted from an unlimited bounty. Now ‘we’ have learned, in my opinion, that what we collectively do will change or modify the world, and what we want from it mightn’t be there anymore. Burning the books, or the scientists, won’t get us what we want either, although better science and technology can. I wonder if George for example realises that in the cabin space between and well behind his shoulder blades when he takes his jet to far places there are active, restless, inventive, people who will use or cause technological change to make the way we have affected the environment work for us, instead of bring us undone.

  12. Zipper

    What the fear mongerers can’t get through to there thick heads is that the climate is changing, and has been for billions of years, we have warm periods and we have cooler periods, it’s never static, always changing, we are in a warmer period now because the earth has come out of a mini ice age, yes for us this was a long time ago, but in natures timeline this was just yesterday, so this very gradule increase will continue for the next 300 years or so, people seem to not realise that when a volcano blows its top it realeases more Co2 then all us humans combined, nobody stresses out about that though?? The truth is there is zero proof that man made climate change is happening, lots of these dodgy models however, but no proof..

    1. Ben Sandilands

      You always manage to combine crap manners, ignorance and a refusal to substantiate your wilder claims all in the same obviously juvenile frame at the one moment. The changes we have seen since the invention of concrete and broadacre land clearing and the subsequent first industrial revolution are far larger and more rapid than the geological time frame for natural cyclical changes in climate. The correlation with rising land and sea surface temperatures is also compelling. The CO2 content in ice cores and tree trunk cores is compelling. The volcanoes that produced brief but very interesting changes in weather, such as Pinatubo and Agung (in 1963-64) emitted copious amounts of large sulpur dominated particles, and, if you can get up from reading comic books or whatever it is that you waste your school years on, there are numerous, accessible, papers as to the composition of most volcanic events of any scale. They deal with the CO2 content found in such emissions. What we see in volcanic ash clouds is, shocking thought it may seem, ash. Not colourless and transparent CO2 at visible wavelength. Is there really any excuse for anyone to be as poorly informed as yourself given readily available information? Why do you invent all this guff about billions of dollars of wasteful spending when you never respond to challenges to provide verification? Coming here, and just shouting at people, is poor navigation on your part. There is plenty of space for fruit loop type rantings elsewhere on social media. There is however space here for people to criticise some of the claims made by those who hold various positions on the science of global warming or climate change whether for or against. My own point of irritation is with those who sometimes it seems willfully, seek to confuse the release of fossil locked carbon with the short term seasonal exchanges of other carbon cycles that characterise what to me is the worst of the less well educated green movement.

    2. Ben Sandilands

      PS This isn’t a period of natural warming if we make reference to the solar cycle since 1996, which resembles that of the Dalton Minimum and the situation in the first decade or so of the 20th century. If those cyclical variations in sunspot activity and length of actual cycle are as important as some solar scientists have argued, then we should have experienced much more by way of outbreaks of unusually cold weather events early in this century than has been the case. However if you go to the ice core records, the difference between the early years of the last century and now is about 100 ppm more CO2 in that period. Start Googling for the Law Ice Dome record and you will quickly pull in enough articles to start your learning process.

      1. Zipper

        Ben the biggest problem I have with all this rubbish is that people in this country honestly think we can make a difference, we are simply too small on a global scale, whatever we do, if we cut our emissions to zero right now, will have absolute zero effect on global temperatures, not when we have the likes of the US, India, Europe, Japan and of course China who open a new coal fire power station every single week! These countries are beyond massive compared to the likes of little old Oz, why should we have to suffer the highest power bills in the world just to make a point that we are doing something, when in reality in makes no difference to the climate at all, please tell me, if we in Australia cut our emissions now, what effect will this have on global temperatures? I’ve asked this many times before but I can’t get an answer.. funny that.

        1. Ben Sandilands

          It’s an opportunity not a problem to those Australians (mostly working abroad, since this isn’t a science friendly society) to invent or refine new technology, creating jobs and wealth beyond your limited world view.
          We have a choice. Do sweet FA and let others take those jobs, and help rise to the challenges, or just buy what we need with an increasingly worthless currency from places where the policy settings are more favourable for innovation and enterprise. I don’t like your defeatist attitude.

          1. Zipper

            Well we are defeated Ben, as long as the likes of China and India are around building coal fire stations every week, then whatever we do is pointless.. again I’ll ask, what will the global temps drop by if Australia cuts emissions to zero right now? You hate answering it because you know it will make no difference whatsoever, which then leads to an even bigger question, why the hell are we wasting our time and money on this rubbish?!

          2. Dan Dair

            you can actually open your generally closed-mind for long-enough,
            I’d be really interested to get your reaction to;
            What if, global warming is actually real.?
            Maybe it’s a natural, cyclical phenomenon. Maybe it’s man-made. Maybe a combination of both.

            it is real,
            do you really thing that doing nothing, because the neighbours are doing nothing,
            will fix the problem.?

  13. Zipper

    So Dan if our contribution does stuff all to global temps, why should our economy suffer just to make a point that we’re doing something? Until country’s like China gets serious then whatever we do is meaningless, if we only had a few more power stations around then our power bills wouldn’t be the highest in the world! Do you understand the pressure this has on our economy? the amount of businesses going under because they can’t keep up with power prices is scary, not to mention the pensioners and struggling family’s that sit in the cold because they can’t afford there bills, this is a disgrace! For a country that is THE largest exporter of energy in the world, yet we have the highest prices! wtf?? And don’t throw me crap about wind farms, and battery storage, wind farms cost a fortune and are not going to be enough, see Germany as a good lesson on the failure of there wind farms, it’s been a disaster! We should of looked at nuclear a long time ago, we have the largest deposits of uranium but ship it all overseas, oh no we can’t use that but hey we have no problem exporting it, just like coal, if we thought coal was killing the planet then don’t export it, but our economy would tank if that happened, because booming economy’s still have plenty of coal power stations, and are building them weekly, while us idiots down here are shutting them down! This is truly the dumb country.

    1. michael r james

      Zipper wrote:

      if our contribution does stuff all to global temps, why should our economy suffer just to make a point that we’re doing something?

      That’s where you rightards get it so wrong. As Ross Garnaut (and Lord whatisname) wrote in their reports almost a decade ago, this can, and should have been, a terrific opportunity for an advanced nation with the best solar, wind and ocean energy resources.
      But we’ve already lost a decade and people like you and your buddy Tony et al will mean we will never grasp the huge (yuuuge) opportunities out there. It is just too easy to dig up coal and pump gas (though it turns out we–ie. you zipper–have become so complacent we don’t even make much money from selling the stuff, especially when we are so inattentive that we sell our own domestic needs too; bravo how much more stupid can we (you) get?).

  14. Dan Dair

    I simply asked you
    “if you can actually open your generally closed-mind for long-enough”……..

    It appears that you can’t even manage that.?
    So what hope is there in asking you to have a critical-look at the source-material for the dodgy websites you get all these stupid ideas from.?

    I’m obviously wasting my time with you,
    so I’ll stop.!

    1. Dan Dair

      “This is truly the dumb country”

      How patriotic of you.?

      Perhaps you’d feel much better if you moved to the USA instead.
      There you can live it up, safe in the knowledge that your idiotic new President is helping to finish the planet off more quickly, so that he can placate a bunch of Midwest miners at the expense of their children’s future.!!

  15. Zipper

    It is a dumb country Dan, totally dumb, both sides of politics are useless, no foreword thinking, just political point scoring, we sell all our vital farmland to the Chinese, who have also made owning your own home unachievable for many, we have internet speeds slower than Kenya, we pay the highest power bills in the world even though we are the largest exporters of energy, the country is also a nanny state, over regulated in everything, the list goes on and on, say what you want about America mate but they are light years infront of us, you don’t become the richest and most powerful country in the world by being stupid..

    1. Ben Sandilands

      The America you rate as ahead of Australia is also light years ahead of your defeatist and insulting bleatings when it comes to new energy technology, often it seems since late last year, ahead of the intellectually crippled mindset of the executive branch in the swamp land of Washington DC. American ingenuity will outclass second rate US politics in any contest, although not I suspect without a struggle or two along the way. Your recent comments are full of inconsistencies like that. As someone who is Australian born but half American by family, I am far more optimistic as to the outcomes from renewable energy technology, and I confess the possibilities of radically improved nuclear energy pathways. I hold great hopes for what Australians will achieve, despite the inanities on all sides of both houses of parliament in Canberra. While the science of global warming and the technology of renewable energy seem to cause so much anger among the ignorant, the viability and opportunities that arise from alternatives to fossil carbon releasing energy will see the conventional energy pathways replaced, in America, and not a day too soon in my opinion, in Australia.

      1. Dan Dair

        I side (as so often) with Ben on this,
        (I have said on these pages before) That renweables are/were an opportunity for a nation to get in on the ground-floor, with suitable investments & appropriate tax-breaks, to enable business to design & MANUFACTURE the cutting-edge designs of power-generation equipment.
        Australia has turned-out not to be a nation which has made anything of that opportunity.?

        There is a debate going-on currently in the USA about renewables.
        The 3 big US manufacturers of solar-PV panels (2 of which are foreign-owned) have camplained ‘Boeing-style’ that they are being undercut by cheaper Chinese imports.
        All well & good you might think,
        The US PV-fitting trade-body is saying the industry could collapse if the Chines imports are banned & the price of having solar-PV then effectively doubles or triples to the householders, because they HAVE to buy US made products.!

        This is a fine example of one of the big issues around protectionism.
        Do you protect your ‘home’ manufacturing industry & around 5 thousand jobs,
        do you not protect those jobs
        & by not protecting them,
        instead protect the 20 or 30 thousand jobs in the PV fitting industry.?
        All 35 thousand (or so) of the above jobs are American.

        The answer at first is obvious……..
        until you think about the consequences
        of protecting your home manufacturing industry.?

        The world is very complex
        & simple answers don’t always work smoothly in real world situations.!

Leave a comment