Most of the recent widely publicized CAT injuries have been on long distance flights between Europe and South Asia.
One thing that’s happened in the past couple of years along that air corridor is the squeezing of flight paths out of Ukrainian, Russian, Israeli, and Afghan airspace.
Planes taking more circuitous routes, giving them less options to avoid weather conditions, much of the flight over hot mountainous terrain… could be a contributing factor to increasing incidents of dangerous turbulence affecting flights, even if the conditions themselves haven’t become more common.
Weird that this is the top-rated comment, as it's directly contradicted by the heat maps in the article, which show increases in CAT all over the globe, in many places that are not routes between Europe and South Asia.
(Also consider that the principal question the article tries to answer is not "are there more CAT incidents?" but simply "is there more CAT?")
I glanced at a few current (as of today) routes, e.g. CDG->SIN[0], which don't fly anywhere near the areas of heavy CAT noted by the heat maps. Hell, let's take a look at the flight mentioned, the LHR-SIN SQ321[1], where a passenger died in may (though, as the article notes, it was later determined not to be CAT): that one doesn't fly through any high-CAT areas (and in fact does fly through Russian airspace).
> giving them less options to avoid weather conditions
The entire characterization of CAT is that it is unavoidable because the cause often doesn't have all that much to do with weather conditions, and even when it does, you don't get (enough) advance warning.
I don't think the comment sounds unreasonable, and I don't find anything weird about the words in the comment itself. It just kinda bums me out that so many people must come here and comment and upvote comments without even reading or skimming the first few paragraphs of the article. This isn't news to me, of course; I've been a frequent HN reader for over a decade now. But it still bums me out.
I've read something more of the opposite before: posts with lots of comments risk being down weighted unless they've received a lot of upvotes. Supposedly something to do with wanting to avoid lower value content which is attracting a large amount of discussion anyways.
I've never heard of anything of this nature regarding comments though.
"Most of the recent widely publicized CAT injuries have been on long distance flights between Europe and South Asia."
OK but you'll need a citation for your assertion and that is only about reported CAT via media sources and not what the article is on about - CAT events worldwide.
The article invokes evidence across the entire planet and cites Prosser et al with 1979 vs 2020 graphics, evidence and discussion. It also concludes that jet streams are where CAT events are intensifying.
The article exists because of several recent high profile CAT incidents.
It cites data from several years ago (before the recent spate of stories) that only talks about increases in CAT-conducive conditions, but says nothing about increases in actual incidents. The article leaves maybe the impression that any recent spike in high profile turbulence events might be a result of the changes in jet stream activity but doesn’t actually provide much justification for that. Other posts on this thread point out that there was no actual increase in reported CAT encounters that correlates with the proposed mechanism so… unclear if the article’s data says much if anything about recent media-reported CAT events.
The whole point of the argument was that changes to routing in the part of the world was contributing to the increases we're seeing. Back the fact that we're seeing increases all over the world suggests that we'd also see increases in Europe/South Asia even without the current conflicts. Therefore it seems like a distraction from the real mystery to focus on it.
Edit: I just realized that the chart is increase of probability between 1979 and 2020, so to modify my comment I’ll just say that it wasn’t just that geographic region that saw an increase. It seemed to correlate with the jet streams
Well the study in the link has a chart of some sort of duration weighted probability of CAT (which somehow ranges from 0 to 2.5 instead of 0 to 1?), which would correct for the total volume of flights because it’s a ratio. It’s more likely that the jet streams are getting more turbulent due to climate change.
An increase in the frequency of clear air turbulence doesn't necessarily entail an increase in reportable accidents and incidents. The NTSB is only notified when a specific set of criteria are met. See 49 CFR Part 830 for details. If the increase in turbulence is all light to moderate turbulence with no serious injuries, there's nothing to report to the NTSB.
This deserves to be the top comment. Turbulence accident statistics are only going to ever reflect clear air turbulence if the aircraft sustained detectable damage or passenger(s) sustain serious enough injuries.
In that case what’s the explanation for clear air turbulence events having an exactly proportionally lower rate of causing damage and injury such that the rate has remained flat despite the increase in events? What’s making turbulence safer?
Edit: this isn’t a rhetorical question. I’m very interested in any proposed actual mechanism. As someone who is very alarmed by turbulence I’d love a reason to believe it’s getting safer.
As I understand it modern US airlines (Delta in specific) employ a meteorology team tasked to predict turbulence and they also run complex turbulence tracking systems that allow one plane that detects turbulence to communicate to a centralized system that allows other planes to change altitude or heading to avoid turbulent areas when possible.
Therefore both can be true at the same time: turbulence events are increasing, but we are also getting better at predicting, avoiding, and dealing with these events.
Flight plans are now algorithmically generated to shave fuel usage.
Because weather forecasts are more accurate, the algorithms write flight plans that take the aircraft closer to storms. This saves fuel while slightly increasing the risk of severe turbulence.
Couple that with the lightweight materials used in modern aircraft, and passengers are likely to experience more frequent moderate to severe turbulence.
There's no reason there couldn't be a statistical increase in turbulence without a statistical increase in accidents if the intensity hasn't crossed a threshold for the amount of turbulence todays planes can safely sustain.
Also, they just looked at 2 years, so there could be cherry picking. Jet stream is affected by el nino. 1979 was weak el nino, 2020 was moderate la nina.
Why do you say that? Just looking at the plots in Prosser et al (2023) it is obvious they had a lot more years than just two.
If you actually read the short paper you'll find they actually used reanalysis data sampled at a rate of every three hours across 42 years to compute their statistics:
> Global ERA5 reanalysis data (Hersbach et al., 2020) [...] were extracted on the 197 hPa pressure level with 0.25° horizontal resolution at three hourly intervals from 1 January 1979 to 31 December 2020. To allow the computation of CAT diagnostics that require vertical derivatives, fields on the 188 and 206 hPa levels were also extracted. The 21 turbulence diagnostics were then calculated from the extracted reanalysis fields every three hours.
How you go from that to "they just looked at 2 years" is beyond me.
Right, and those two years are generationally distant. Another question I have is if pilots have a stable mechanism (that is, an unchanged objective sensor or something) that records the CAT or if it’s recorded by pilots, whose sensitivity to CAT might differ over time. Didn’t mention in the article how it’s measured.
CATs are recorded in pilot reports using terms like "light", "moderate", "severe", and "extreme" which each have a definition. I.e. severe is "Occupants are forced violently against seat belts or shoulder straps. Unsecured objects are tossed about. Food service and walking are impossible." I think only severe and extreme turbulence need mandatory reports and the lower two levels are a bit more subjective ("Food service and walking are difficult")
Newer planes have sensors to measure eddy dissipation rates which are an objective measure of turbulence but I don't know how widespread those systems are and whether they get reported anywhere. They're mostly used for long distance transoceanic flights.
Unsecured objects being tossed around has no real meaning, it’s about controllability of the aircraft.
I’m a pilot and it’s been a while since I went over PIREPS but generally severe is rarely used, severe means the turbulence is so bad you can no longer control the aircraft. What most passengers imagine as severe is probably light turbulence. Most of the time it’s not even reported. As a side note if you’re ever on an aircraft and not secured at all times, you’re making a huge mistake.
Have there been any reports of true severe clear air turbulence (where the pilot cannot control the plane) or are all of these cases not technically severe because the pilots were in control the entire time and it was just a bumpy ride?
Another question I have is what do you do in that scenario if you can't control it? Just ride it out and hope for the best?
You don't have to live in fear of turbulence when flying, just keep your seatbelt on when you're seated. Turbulence is fairly rare but it's still a numbers game. The probability that you experience it the 99% of the time you're seated is much higher than the probability of experiencing turbulence while standing, especially since pilots proactively turn on the seatbelt sign when turbulence is expected.
Certainly no detectable trend in that data. But the accident frequency is so low that the random variation dominates and makes it impossible to distinguish any trend.
What is demonstrably increasing is CAT, due to climate change. But considering how infrequent these incidents are we might not see a clear increase for several decades.
Do we really not record turbulence sensor data off the airplanes and download it when they’re on the ground?
I’m also surprised that these airplanes have on demand satellite TV streaming to these airplanes but airlines claim that it costs 100k to add that to existing planes. There’s just no way it’s 100k per plane - there must be a cheap way to retrofit the data without having it be reliable since it’s opportunistic. And heck, France is doing it every 4 minutes for their planes so why can’t Americans figure out how to do it.
> Do we really not record turbulence sensor data off the airplanes and download it when they’re on the ground?
No, accelerometer data is only recorded to the FDR. Which has a limited storage window (1-24 hours depending on the aircraft) and is slow to download requiring moderately specialized equipment and a technician to carry out the task. Aircraft downtime and technician hours are both expensive and in short supply.
> I’m also surprised that these airplanes have on demand satellite TV streaming to these airplanes but airlines claim that it costs 100k to add that to existing planes. There’s just no way it’s 100k per plane - there must be a cheap way to retrofit the data without having it be reliable since it’s opportunistic. And heck, France is doing it every 4 minutes for their planes so why can’t Americans figure out how to do it.
Everything on airplanes is expensive. Even cabin amenities. You have to prove it won't start a fire, was installed correctly, won't interfere with other equipment, won't interfere with the aircrafts structure, and again requires technician hours and aircraft downtime.
> No, accelerometer data is only recorded to the FDR. Which has a limited storage window
Apple and Google could fix this my streaming accelerometer data to the ground when people are connected to in-flight wifi. It is fairly easy to identify which phones out of a set are the stationary ones.
I find it hard to believe that the headsets they are using for software and hardware meet that level of criteria. They’re clearly using off-the-shelf parts. Some amount of care is called for sure, but 100k to apply a software patch or tweak the tech in FDRs which are swappable and upgradable? A flight recorder is 10k. You can’t tell me it costs 90k to install a new one capable of sending data over the satellite link in bursts. Clearly other countries and airlines with a similar safety record and cost of living and salaries are able to accomplish the feat.
You’re solving a human problem with technology. Pilots are resistant to data collection because of the proven track record of airlines using it against them. Unintended consequences are fatal in aviation. Saying “it ought to be easy” is an immediately disqualifying statement. You should ask instead why it is so expensive. Then decide if there’s a margin worth eroding.
What human problem am I solving with technology? I’m just saying we should have public data about turbulence so that we can understand changes to the jet stream. I’m not talking about making planes safer or solving human errors. I’m not sure how this data could possibly be used against pilots. I’m not talking about recording the cockpit; just the sensor data about what the plane is doing and experiencing.
> You should ask instead why it is so expensive.
That is literally my question. I’m highlighting that 100k seems really high to make a system that opportunistically transmits data we are already capturing locally. Rather than a flippant “airplanes should be expensive”, why not ask what is the cheapest retrofit we can do that doesn’t change the safety profile. As I said, this system should not be in the critical path and shouldn’t be a required other than the airplanes should generally be maintaining it to be functional (i.e. the SLA can be 75-90% and still provide tremendous value instead of the 100% SLA target for flight critical components which is what that 100k price tag sounds like).
That this is something highlighted by crash investigators as something that would help in corner cases like incidents over the ocean is just gravy.
Meanwhile an accelerometer, microcontroller and a years worth of storage for the data probably all could be made with $5 worth of parts and a summer intern...
Oh come on. It's not like raspberrypi is going to force plane down.
Also there's likely 200 accelerometers on board already. Onboard wifi is becoming ubiquitous. Perhaps an app that trades in wifi time for accelerometer time would be good trade-off. And wouldn't require tons of certification.
Well, you have to have paperwork claiming it was installed correctly. You don't _have_ to install it correctly. See e.g. doors installed so correctly that they blow out in flight etc.
What's the point of your comment? Should we just install a bunch of accelerometers on planes with faked paperwork because some people faked some paperwork somtime?
Sounds like you're upset at Boeing and figured you would tell us you're upset on an unrelated thread. Note that it doesn't really matter if you are right to be upset at Boeing or not. It's still unrelated.
I think his point is that the proof is expensive, not the act itself. Reminds me of rivets in composites joined by adhesives. The benefit is inspectability. The cost is diminished strength.
Proof that it was installed and working correctly is super easy. Multiple airlines fly the same route. The airlines should be feeding the data to the government and the government can cross-validate that the data is legit for routes that have more than 2 airlines. + the jet stream is quite large so even not the exact same route should still be able to highlight airlines doing fraudulent data by. If they’re not sending data, that’s also super easy to tell.
At some point the cost of trying to lie and cut corners becomes worse than the cost of compliance and the airlines and airplane companies will just become good at doing a good job here.
Making sure this whole operation is set up sounds like a lot of work to me. If you find setting up this kind of thing super easy, I think you should just do it. The benefits seem readily apparent.
Some aircraft are equipped with a system that records parameters in flight, and sends it via 4G when on the ground. This is used for preventive maintenance mostly. It’s a service that’s more and more common.
Yeah I feel like the FAA should require the airlines to share some of the data so we get research into the jet stream that we can cross correlate with other data sources.
There's essentially no cheap way to add anything to an airplane. Most changes will require extensive testing, verification, and sometimes certification when it comes to planes.
But anyway, where are you seeing a claim that it costs $100k to record and save turbulence sensor data? I don't see anyone upthread claiming that, and the article doesn't touch on it at all.
I read it in another article on the topic researching before commenting. Just didn’t bother to cite it but that was the official reason given as to why America doesn’t do this.
If satelite TV is down, some passengers are mildly annoyed. If a regulatory required part of the aircraft is non-functional, you're not going flying today.
You’re saying it’s impossible to have an optionally required feature? If the satellite TV is down some sensor data isn’t sent. Why would that be cause for grounding the plane? You could easily make the regulation an SLA like all routes flown must be sending data for 90% of the flights on that route for the month and failures to meet the SLA are investigated.
Also I’ve flown a bunch and I’ve rarely seen the Internet link go out except where there’s technical limitations like crossing the ocean where they can’t maintain an internet and have to rely on preprogrammed content. Given how much money they make from cabin internet, the airlines are clearly incentivized to apply pressure to keep those things running. I doubt I’ve seen anyone be really annoyed when there’s technical difficulties. Most people who fall into that category would have made other arrangements for entertainment anyway.
There is a big factor out there that is 'masking a rise in incidence of CAT from accident stats'. It's Aerospace Engineers and the aviation engineering and safety community.
--
Most CAT events (seen so far) are survivable by current aircraft designs, so you can have an increase in CAT without a spike in crashes and other accidents.
Could be an inverse relationship, too - the more frequently they occur the more experience, training and guidance the pilot, and the other crew members get to manage it: how to control the the airplane, urge passengers to wear seatbelts more, etc.
The article seems to say that other than direct passenger injury, the issue is premature airframe fatigue, which I guess that if remarked on inspections, does not end up in the incident category.
Yeah, you should have more concern over human error and Boeing than this. But, boy, the more I have flown and the older I am, the more I get anxious during turbulence when I fly.
Thank you! That's definitely a great way to look at it. Complacency and habit breed accidents. Although not the the Boeing/mechanical issues. Still worried about the ghost in the machine or gremlins!
> Several booked passengers cancelled their tickets at the last moment to see a ninja demonstration. These passengers, Albert R. Broccoli, Harry Saltzman, Ken Adam, Lewis Gilbert, and Freddie Young, were in Japan scouting locations for the fifth James Bond film, You Only Live Twice (1967).
The James Bond franchise would likely have been quite a bit different had Broccoli died in 1966. Crazy to think he and his colleagues cheated death because they wanted to play tourist a little bit longer than originally scheduled.
>The Boeing 707 jetliner involved disintegrated mid-air
I'm guessing their use of "disintegrated" there is supposed to be taken literally as dis-integrated, but upon first read, I took it for its more colloquial meaning (which to me is closer to pulverized, turn to dust, dissolve etc).
Well, assuming that there is indeed more turbulence, that could also mean more vigilance against accidents, so that could even itself out as safety regulations get stricter than in the past. Also, this is mentioned in the conclusions:
> The report includes an important discussion of the risk to unrestrained occupants onboard aircraft, including flight attendants – who account for nearly 80% of those seriously injured in turbulence-related accidents. Key recommendations in the report are intended to help ensure better protections
for flight attendants
... which makes me think of two more possibilities:
1 - I suspect any careless flight attendant involved in a turbulence-related accident would learn their lesson after the first time, and take better safety precautions. Perhaps that is a stabilizing factor on the number of accidents, since the number of flight attendants who need to learn that lesson the hard way is probably more a function of how many new flight attendants enter the field than it is a product of how much turbulence there is.
2 - Flight attendants under-report minor accidents so they don't get into trouble for not respecting safety rules
Of course, this is pure speculation (and assuming that the premise of there being more CAT incidents holds up), I'm sure the actual document goes into this kind of thing in more detail but I don't have the time to dig through 115 papers.
> I suspect any careless flight attendant involved in a turbulence-related accident would learn their lesson after the first time, and take better safety precautions.
They are briefed, no need to learn their lessons after the first time. However, it's part of their job to walk around the plane (eg to serve food), and so they're less likely to be seated than pax. That is the (rather obvious) explanation for the fact that they constitute a very high proportion of victims, not "careless"ness.
> The Prosser report outlines one of the primary reasons for the increase in CAT events as the intensification of the jet streams, driven by the warming of the planet. As global temperatures rise, the temperature gradients between the equator and the poles become more pronounced, strengthening the jet streams and increasing the likelihood of turbulence .
I was under the impression that, as the poles are MORE affected by global warming, the jet stream is becoming weaker? is that incorrect?
The jet stream is getting stronger (and its path becomes more erratic), but the reasoning provided in the article is simplified to the point of being wrong.
The projected warming at the North Pole is much stronger than the projected warming at the equator, decreasing the temperature gradient. However the moisture carrying capacity of air increases exponentially with temperature. Since the equator starts warmer, a given change in temperature has a bigger effect on moisture carrying capacity. It turns out that heating up the equator by one degree Celsius and the North Pole by 2 degrees Celsius increases the moisture capacity gradient, despite the temperature gradient dropping. And that increasing moisture capacity gradient strengthens the jet stream.
(at least that's the intuitive reason they were probably going for. In reality there are many factors and a good bit of "if we simulate it this keeps happening")
But I also thought that it was the jet stream getting weaker that caused it to meander more (which sounds like it could increase CAT events ??), which we seem to be observing ??
The jet stream is also driven by temperature differences. Same with most wind and weather, it's all various forms of heat engine.
(Edit: though apparently the additional moisture in the Tropics more than counteracts any reduction in temperature difference: see link in Retric's comment)
That is correct, as a longer term trend at least while paradoxically, we are also seeing periods of record strength in the Jet Streams.
The truth is there are many oscillations and teleconnections(themselves being impacted by global warming) which influences this temperature gradient on a local/seasonal basis. QBO, El Nino/La Nina and mountain torque events to name a few can move and shift heat at the tropopause in a short period of time and is why we see this wider variance at both ends of the spectrum.
I think the seasonality of the polar environment is a critical factor - while warming is expect to decrease the average equator-to-pole temperature gradient (as all models predict faster polar warming than equatorial warming by a large margin), winter is still winter as the polar axis is tilted, so steep atmospheric gradients are expected over that seasonal period.
The poles warm FASTER than the equator. Thus, the global temperature gradients are getting smaller.
And as a result, not only does the Jetstream weaken: as a result, weather patterns become more stable which leads to greater continuous periods of draught or flooding.
Your intuition is incorrect. Global warming increases the jet stream.
“The new study, by University of Chicago Professor Tiffany Shaw and NSF NCAR scientist Osamu Miyawaki, uses climate models to show that climate change intensifies this density contrast because moisture levels for air above the tropics will increase more than above the poles.”
The article cites the Prosser Report which contradicts this claim, but I find it hard to understand how this could be true for very long. Why wouldn't the atmosphere stabilize as gradients diminish?
Because the earth's rotational axis is not perpendicular to incident sunlight (hence dark polar winters). As winter sets in, gradients steepen relative to warming equator. It's all complicated by the general increase of atmospheric water vapor as warming proceeds, which can have different effects depending on whether the water vapor is gaseous or forms cloud droplets, which reflect sunlight. It's a hard physics problem.
It’s a heat engine but more than just temperature changes are occurring.
“The new study, by University of Chicago Professor Tiffany Shaw and NSF NCAR scientist Osamu Miyawaki, uses climate models to show that climate change intensifies this density contrast because moisture levels for air above the tropics will increase more than above the poles.”
I guess it's like someone putting water on the coals in a sauna and the people feel a huge wave of heat due to the increased heat transfer, even though they've literally cooled down the coals.
I also think some of the confusion is coming from the use of the term 'weakening'. It is true that the primary jetstream wind pattern is weakening relative to it's stabler state.
That weakening means the jetstream meanders more, with more latitudinal movement in its form.
The strength overall of the jetstream wind is weaker when it's meandering, but can also be much more intense in places.
This says nothing about humidity or energy or pressure, just windspeed and direction.
Shameless plug here. I work at SkyPath (https://skypath.io) we monitor and collect CAT data from 1000's of flights in real time and predict CAT events with the help of an AI model. Pilots are extremely happy with our solution, we signed several of the major airlines in US and have active evaluation programs with several others.
I see the site claims to save fuel, is this in the form of providing routing? I assume that patching data needs to get in to the autopilot system at some point, how does that work?
More predictable routes and minimizing encounters with CAT can indeed help reduce fuel consumption while maintaining safety. This is a relatively small saving for each flight which can add up to a big chunk at the end of the year.
Signed as in purchased a subscription for our service to provide data from their aircraft (using iPad sensors pilots are using) and get real time alerts and predictions regarding their flight and route.
This type of technology would be incredible in my opinion, and I’m also of the opinion that increased turbulence (assuming it is actually increasing) could be easily tied to climate change and the recent warming of the pacific and Atlantic oceans due to regulations on sulfur in cargo ship fuel (but that’s a tangent to this topic)
There is also just a huge increase in global air travel, which should increase the number of total incidents. The number of commercial flights doubled between 2004 and 2019, and is expected to continue on that trend for some time.
Could this be internet-enabled flight bias? Now that we have more and more WiFi enabled flights, more people posting about it on socials...so public awareness grows but as indicated before only incident-related stats are being recorded. One can extrapolate if incidents including damage or injury are not increasing per capita of flights it's probably not a trend.
I hate flying with passion and get extremely scared when flying through turbulences but, there was a journalist in my country, that also had experience as a pilot and said once on TV that during turbulences, is one of the safest moments in a plane. I don't remember the reasons but is there anybody in here with knowledge in the field that could confirm/deny this?
That's just not true. No turbulence is better than turbulence.
That said, experiencing light chop on a modern large airplane presents no danger to the airframe or properly secured passengers. You really should be strapped in, though, especially if you're on a small plane. Wake turbulence, for example, actually does present a significant risk to smaller aircraft.
It is safe because you are flying. Airplanes almost never have issues at altitude. Problems occur when closer to the ground. Landing/takeoff are the most dangerous times, the transitions between flying and not flying.
My first guess is that during turbulence everyone has their seatbelt on. No one is walking around the cabin. It’s only at the start of unexpected turbulence that anyone should get hurt. Once your seatbelt is on things have to get pretty bad to get hurt.
The standard that you must meet to get a pilots license is being able to hold your altitude within 100 feet in a 360* turn. A 40 foot
He's not saying the drop was 40 feet instantaneously, he's saying the turbulence and the subsequent recovery only caused a 40 foot deviation from the assigned altitude.
Just for reference, a descent rate on a standard flight is pretty normal at 40 feet per second. Some descent profiles can double that. The NCAA diver will hit the water at 46 feet per second.
I agree. It’s funny to think of the gap between safety and scary when talking about turbulence. Large planes can take an absolute beating and be completely fine, but it could feel like the end of the world inside.
A modern airliner is rated to something like 3-4G's including the safety factor, probably much more if it's not at max takeoff weight. I'm sure you could do a Mythbusters-style test but I'd assume most passengers would pass out from the negative and positive G forces long before the aircraft structurally failed.
You'd lose that bet. The wings would fail long before people blacked out. They're only required to withstand 2.5g positive. Blacking out takes more like 6. We can see from various crashes that that sort of G load does in fact cause most wings to fail.
Aircraft have to be built light for the sake of efficiency (or even, just, being able to get off the ground.
There are certainly factors of safety... but not 3x+. Probably closer to 1.5.
"(b) The positive limit maneuvering load factor n for any speed up to Vn may not be less than 2.1 + 24,000/ (W + 10,000) except that n may not be less than 2.5 and need not be greater than 3.8—where W is the design maximum takeoff weight.
(c) The negative limit maneuvering load factor—
(1) May not be less than −1.0 at speeds up to VC; and
"
The 2.5 number is important. That right there is the +2.5 to -1.0 requirments for transport (i.e. seating more than 19 passengers) category aircraft.
Here's a quote from Boeing: "Our airplanes are built to withstand 3.75 G load before there is any kind of damage — that's almost four times gravity,” said Doug Alder, a spokesman for Boeing. “Some of the worst turbulence gets in the range of 2 to 2.5 G's, well below the damage tolerance.”
3.75 is not nearly enough to cause a blackout. It's also exactly 1.5 (typical airplane factor of safety) times 2.5
I feel the same way about flying but a boating enthusiast friend bought up an interesting analogy. He asked me if I enjoyed boating and I said yes. Then he asked me if it was fun when you run over waves bouncing around and I said yes. Then he said that is exactly what turbulence is - wakes and waves in the air the plane is bouncing on so relax and enjoy the ride. Kinda made me feel a little better since I could now visualize what is going on but still - eh, Id rather be on terra firma.
If you've ever sailed, a more apt analogy would be heeling over extensively (and potentially capsizing) due to a gale. You could be sailing along just fine and then all of a sudden you're overpowered. A sail, after all (at least when sailing towards the wind) acts just like a wing of a plane.
This seems like one of those topics that seems to be eliciting some response we might consider normal if it was code switched into Bay Area or NYC speak but seems to be getting a lot of pushback because it sounds like it's coming from particular airline boosters.
This isn't to say either of those things really happen just it sometimes sure seems like it.
I can't tell if it's just me or something with flights but recently when I take flights I get an intense headache that isn't similar to other headaches.
For a few months, I used to have headaches too in the last 10 minutes before landing of every flight. Since I had a surgery for my sinusitis a few months before, I thought it was because of some air pressure buildup in my maxillary sinuses that wasn't returning to normal air pressure fast enough. Now every time I am close to landing I make sure the air circulates through both nasal cavities very well and I haven't had any problems anymore.
"Are Clear Air Turbulence events happening more often?
In a word, yes. Recent studies have shown a significant increase in the frequency and intensity of CAT conditions over the past few decades. This increase is linked to several factors, most notably climate change."
We've had this invisible hand of the market to regulate ourselves. Now we have the invisible hand of the planet.
It won't be a fun ride either.
Commercial pilot here. Instead of climate change, we should be talking about continuous descent profiles (CDPs) that have become more common in the past years 5-10 years. These profiles with idle engines allow for a smoother, more fuel-efficient descent by reducing the need for level-off segments. However, CDPs can increase the perception of turbulence during descent. This is because aircraft remain at higher altitudes for longer periods, where atmospheric instability and wind shear are more pronounced. This increased turbulence is not due to climate change but rather the result of these optimized descent procedures aimed at reducing fuel consumption and minimizing environmental impact.
Interesting! I didn’t know that descent profiles had changed this decade. Now that you mention it, I seem to recall far less leveling off than when I was younger, at the very least you’ve incepted the idea into my head now.
Also worth noting that to a passenger, CAT is the worst feeling you’ll have on most flights — the “oh shit we’re not flying anymore” vibe is real bad, and usually when you hit proper air again, the sudden jerk feels bad as well.
As someone with like 8 flight hours to my name, I’ll say to a learning pilot, stalling feels much worse than CAT would, it’s a different sort of not flying, it’s like “oh shit the plane forgot how to fly, what now”.
If plane wings were hinged (allowing a wing to flop down, but not up), then even the worst turbulence couldn't cause negative G in the cabin. That would pretty much eliminate injuries.
Obviously the wings need to lock into place for landing, and many structural elements of the craft would need to be redesigned.
One day we will research a boson particle that can be fired at the air and cause an abrupt polarization allowing for planes to travel through with very little air resistance.
> [Clear Air Turbulence] is particularly common around the tropopause, the boundary layer between the troposphere and the stratosphere, at altitudes between 7,000 and 12,000 meters (23,000 to 39,000 feet) .
Oh, excellent the altitudes that 99% of aircraft fly at, unaffecting the ultra rich who fly private jets at 40,000k-50,000k+.
Private jets don't really fly at 50k that often but I'm sure there are some that can. 40-42k is pretty common though. There are a handful of reasons. In no particular order: 1) additional separation between recreational private flights and scheduled commercial flights 2) higher performance in small private jets with typically less than 1k lbs of people and cargo 3) winds are generally faster the higher you go so you'll usually go about at high as you're able, at least in one direction.
Most private jets aren't someone flying a billionaire around in a $60M Gulfstream, they're $3M toys being flown around by the owner to go to their ski trip.
> 3) winds are generally faster the higher you go so you'll usually go about at high as you're able, at least in one direction.
I recently flew from NYC to Lisbon, Portugal and it was 6.5 hours there (flying east) and 7.5 hours back (flying west) because you go with and against the jet stream.
I wonder if there's a noticeable difference if you fly at a lower altitude against the wind. It didn't seem like the plane adjusted for that, it cruised at the same altitude both ways from what I remember. Both flights used the same exact plane type (A330neo).
Airlines have dispatch folks that spend a lot of time deciding what altitude and route to file. Yes there are defaults so it's certainly possible they were busy and just filed the same but especially days apart it's likely that was the optimal altitude.
They're also looking at fuel economy so even if it takes longer if the air is thinner and they burn less fuel they may still save money. I imagine there's a certain distance where those two lines cross that is probably baked into the dispatch software for each plane model.
Note also that at higher altitudes the air is less dense, but the plane should fly at the same indicated/calibrated airspeed to generate the same lift, which means that it flies faster (at higher true airspeed).
Basically, with aircraft mass and angle of attack unchanged, \rho v^2 must be constant, so smaller density \rho -> higher air speed.
You got some good answers below, but in addition to those, also thinner air = less felt turbulence, so it’s more comfortable (provided your cabin pressurization is good).
You can fly over the tropopause depending how high it is at the specific location (can be lower or higher than the numbers listed) but, by definition, it'll only be "common" to observe turbulence in the range 99% of planes actually fly. I wouldn't read too much into that. As some others pointed out the height difference probably more due tot he space being faster and unused since commercial flights stay to where is more efficient.
I wonder if this is like an immune system response by mother nature, it’s attacking the thing that’s warming it up i.e. air travel? Self correcting systems
They haven't actually analyzed reported turbulence, it's just a simulation study: "Turbulence data from aircraft could also be analyzed, but the time period for which quantitative, automated measurements are available is far shorter than the 42 years covered here, making trend detection problematic."
One thing that’s happened in the past couple of years along that air corridor is the squeezing of flight paths out of Ukrainian, Russian, Israeli, and Afghan airspace.
Planes taking more circuitous routes, giving them less options to avoid weather conditions, much of the flight over hot mountainous terrain… could be a contributing factor to increasing incidents of dangerous turbulence affecting flights, even if the conditions themselves haven’t become more common.