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Is Clear Air Turbulence becoming more common?

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Re: Is Clear Air Turbulence becoming more common?

#81

Post by vlovich123 »

TylerE wrote: post #56
vlovich123 wrote: post #51

Earlier quoted context omitted.

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.…

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.

Re: Is Clear Air Turbulence becoming more common?

#82

Post by photochemsyn »

thiel wrote: post #2

> 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…

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.

Re: Is Clear Air Turbulence becoming more common?

#83

Post by photochemsyn »

elevation wrote: post #35
konschubert wrote: post #7

Earlier quoted context omitted.

That’s also what I read: 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.

> The poles warm FASTER than the equator 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.

Re: Is Clear Air Turbulence becoming more common?

#84

Post by renewiltord »

lucianbr wrote: post #67
throwaway-blaze wrote: post #63

Earlier quoted context omitted.

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.

Re: Is Clear Air Turbulence becoming more common?

#85

Post by makestuff »

oceanplexian wrote: post #72
throwup238 wrote: post #64

Earlier quoted context omitted.

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 servi…

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…

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?

Re: Is Clear Air Turbulence becoming more common?

#86

Post by orhmeh09 »

oceanplexian wrote: post #72
throwup238 wrote: post #64

Earlier quoted context omitted.

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 servi…

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…

Is using the bathroom or stretching your legs advisable?

Re: Is Clear Air Turbulence becoming more common?

#87

Post by septic-liqueur »

stouset wrote: post #75
rootusrootus wrote: post #58

Earlier quoted context omitted.

Best I can tell, 1966. https://en.m.wikipedia.org/wiki/BOAC_Flight_911

Then I think we can safely worry about other things than turbulence :)

But you never know... You might be the first one :-)

Re: Is Clear Air Turbulence becoming more common?

#88

Post by throwup238 »

orhmeh09 wrote: post #86
oceanplexian wrote: post #72

Earlier quoted context omitted.

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…

Is using the bathroom or stretching your legs advisable?

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.

Re: Is Clear Air Turbulence becoming more common?

#89

Post by User23 »

alfalfasprout wrote: post #74
_moof wrote: post #71

Earlier quoted context omitted.

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.

Re: Is Clear Air Turbulence becoming more common?

#90

Post by BlueTemplar »

wongarsu wrote: post #40
the_sleaze_ wrote: post #4

Earlier quoted context omitted.

You might be thinking of the Gulf Stream, which is an oceanic current and definitively weakening, rather than the jet stream, which is an air current.

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 giv…

Thanks for the detailed explanation.

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 ??

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