Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Is Clear Air Turbulence becoming more common?

flightradar24.com

Post reply on HN
Print view View original

151–160 of 163 posts

Re: Is Clear Air Turbulence becoming more common?

#151

Post by [deleted] »

_moof wrote: post #71
w14 wrote: post #29

This does not seem to be borne out by the accident statistics, which apparently show no trend in turbulence related accidents. ( https://www.ntsb.gov/safety/safety-studies/Documents/SS2101.... ) I don't know if there are other factors which might be masking a rise in incidence of CAT from accident stats?

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.

[deleted]

Re: Is Clear Air Turbulence becoming more common?

#152

Post by cassepipe »

w14 wrote: post #29

This does not seem to be borne out by the accident statistics, which apparently show no trend in turbulence related accidents. ( https://www.ntsb.gov/safety/safety-studies/Documents/SS2101.... ) I don't know if there are other factors which might be masking a rise in incidence of CAT from accident stats?

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.

Re: Is Clear Air Turbulence becoming more common?

#154

Post by oron »

pc2slow4webpack wrote: post #146
oron wrote: post #136

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.

Re: Is Clear Air Turbulence becoming more common?

#155

Post by vlovich123 »

kelnos wrote: post #130
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.…

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.

Re: Is Clear Air Turbulence becoming more common?

#156

Post by bozhark »

oron wrote: post #139
HeatrayEnjoyer wrote: post #138

Earlier quoted context omitted.

Signed? What does authenticating have to do with it? Is there doubt about data providence?

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.

Embedded systems or tack-on? This seems like the internal accelerometer would be adequate?

Re: Is Clear Air Turbulence becoming more common?

#157

Post by bozhark »

TylerE wrote: post #100
oceanplexian wrote: post #73

Earlier quoted context omitted.

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+. Proba…

I would like proof of this absurdly low 2.5g wing rating.

Re: Is Clear Air Turbulence becoming more common?

#159

Post by renewiltord »

vlovich123 wrote: post #125
renewiltord wrote: post #84

Earlier quoted context omitted.

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 sendin…

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.

Re: Is Clear Air Turbulence becoming more common?

#160

Post by TylerE »

bozhark wrote: post #157
TylerE wrote: post #100

Earlier quoted context omitted.

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+. Proba…

I would like proof of this absurdly low 2.5g wing rating.

It's right in the FAA regs.

https://www.law.cornell.edu/cfr/text/14/25.337

"(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

Post reply on HN