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Is Clear Air Turbulence becoming more common?

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Re: Is Clear Air Turbulence becoming more common?

#61

Post by dheera »

MadnessASAP wrote: post #57
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.…

> 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 suppl…

> 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.

Re: Is Clear Air Turbulence becoming more common?

#62

Post by supportengineer »

vlovich123 wrote: post #51
ImaCake wrote: post #46

Earlier quoted context omitted.

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.…

Almost every single passenger is carrying an accelerometer with them. We just have to use that data.

Re: Is Clear Air Turbulence becoming more common?

#63

Post by throwaway-blaze »

MadnessASAP wrote: post #57
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.…

> 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 suppl…

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.

Re: Is Clear Air Turbulence becoming more common?

#64

Post by throwup238 »

dclowd9901 wrote: post #50
cpncrunch wrote: post #33

Earlier quoted context omitted.

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. https://ggweather.com/enso/oni.htm

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.

Re: Is Clear Air Turbulence becoming more common?

#65

Post by loopdoend »

bparsons wrote: post #44
Octabrain wrote: post #31

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?

Commercial airliners are built for extraordinary stress on the airframe. You can get a taste of it here: https://www.youtube.com/watch?v=--LTYRTKV_A Other people will correct me if I am wrong, but I believe the last time a large commercial airliner was lost to turbulence was 1966. https://en.wikipedia.org/wiki/BOAC_Flight_911

> Film footage shows Flight 911 taxiing past the still-smoldering wreckage of Flight 402 immediately before taking off for the last time.

Wild how far we've come.

Re: Is Clear Air Turbulence becoming more common?

#66

Post by antoniojtorres »

aidenn0 wrote: post #54
ThinkingGuy wrote: post #49

Earlier quoted context omitted.

Airline pilot/author Patrick Smith has a pretty informative article about turbulence on his website: https://askthepilot.com/questionanswers/turbulence/

"Fewer than forty feet of altitude change" A 40 foot drop is pretty scary; by comparison, an NCAA dive platform is 33 feet.

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.

Re: Is Clear Air Turbulence becoming more common?

#67

Post by lucianbr »

throwaway-blaze wrote: post #63
MadnessASAP wrote: post #57

Earlier quoted context omitted.

> 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 suppl…

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.

Re: Is Clear Air Turbulence becoming more common?

#69

Post by dghlsakjg »

aidenn0 wrote: post #54
ThinkingGuy wrote: post #49

Earlier quoted context omitted.

Airline pilot/author Patrick Smith has a pretty informative article about turbulence on his website: https://askthepilot.com/questionanswers/turbulence/

"Fewer than forty feet of altitude change" A 40 foot drop is pretty scary; by comparison, an NCAA dive platform is 33 feet.

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.

Re: Is Clear Air Turbulence becoming more common?

#70

Post by MisterTea »

Octabrain wrote: post #31

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?

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.
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