
A pilot explains turbulence - sohkamyung
http://www.businessinsider.com/pilot-explains-turbulence-safe-2017-8/?IR=T
======
SAI_Peregrinus
Here's one of the best pictures illustrating the wake of an aircraft in flight
I've seen:
[https://s00.yaplakal.com/pics/pics_original/7/3/7/4872737.jp...](https://s00.yaplakal.com/pics/pics_original/7/3/7/4872737.jpg)

~~~
0xfeba
Looks like a Tu-95 bear or variant.

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ddoran
Patrick Smith, the author and eponymous "pilot" in the title, has been writing
interesting articles about flying and a pilot's life for years. He is as much
a traveler as he is a pilot and loves what he does. If you have any interest
in flying or travel but have somehow not come across Patrick Smith before,
check out his archive [1] and his book [2] Pilot Confidential, an update of
his earlier book, Ask The Pilot, named for his now-defunct column at Salon.com
iirc.

[1]
[http://www.askthepilot.com/archives/](http://www.askthepilot.com/archives/)
[2] [https://www.goodreads.com/book/show/16235130-cockpit-
confide...](https://www.goodreads.com/book/show/16235130-cockpit-confidential)

~~~
sleavey
I also find the Aviation StackExchange site [1] interesting. The weekly
newsletter [2] contains just enough interesting stuff for a mildly interested
occasional flier like myself.

[1] [https://aviation.stackexchange.com/](https://aviation.stackexchange.com/)

[2]
[https://stackexchange.com/newsletters/newsletter?site=aviati...](https://stackexchange.com/newsletters/newsletter?site=aviation.stackexchange.com)

~~~
gbacon
Even better: become a pilot!

[https://www.aopa.org/training-and-safety/learn-to-fly/how-
do...](https://www.aopa.org/training-and-safety/learn-to-fly/how-do-i-become-
a-pilot)

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mannykannot
In a glider, turbulence is often the first indication that you are flying into
a thermal that will lift you up, while the sinking or neutral air between
thermals is often smooth. After having experienced this for a while, the onset
of turbulence triggers positive emotions, even when you are in an airliner.

~~~
clueless123
Yea! when the beep of the vario kicks in, is like: free fuel!

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eric_h
Personally, I _love_ turbulence. I'm thoroughly disappointed when the pilot
announces they'll be changing altitude to avoid it. It's literally the most
interesting thing that can happen while flying.

~~~
dahart
I am _so_ jealous! I hate turbulence, and I can't even explain why. I have a
USPA C license - I've flown in enough rickety planes to get certified to
skydive into public venues - and turbulence still causes my blood to boil.

You would love this: one time I flew from Chicago to Ithaca on a small
commuter plane, and the pilot told us it'd be bumpy due to area storms. It got
pretty bumpy, and the girl sitting next to me was a lot worse off than I was,
I didn't know her but she grabbed my hand and was squeezing so hard it hurt.
Maybe ten minutes into one of the turbulent spells, the cockpit door flew open
and the pilot and co-pilot were going "YEE-HAW" and doing the rodeo rope. My
chin hit the floor, and so did everyone else's when we all realized they'd
been hitting the roughest parts of the storms they could find on purpose.

~~~
eric_h
You are absolutely right. That is literally my definition of a good time on a
flight. My experience in smaller planes is rather limited, but the time I've
spent on those little prop driven puddle jumpers has always been more
enjoyable, as the ride does tend to be a bit bumpier.

I've also been on planes with friends who have an abject fear of flying. Throw
in a dash of turbulence to a flight like that, and there is literally nothing
you can do temper someone's fear of the situation (short of sedatives).
Definitely not as fun.

Random aside, I went hang gliding once (tandem w/experienced pilot) and ended
up going on a particularly "bumpy" day, which all the experienced pilots said
with a positive attitude. Bumpy days are days with lots of updrafts and
therefore more potential flight time per launch. Definitely felt like
turbulence in an airplane, minus the walls and windows ;)

I've still yet to jump out of a perfectly good airplane, but it's definitely
on my bucket list.

~~~
dahart
> there is literally nothing you can do temper someone's fear of the situation
> (short of sedatives). Definitely not as fun.

It's so weird. I know consciously that turbulence isn't a safety risk. I know
that next to zero planes have gone down due to turbulence, and that specs for
modern wings allow for like 15 vertical feet of flex. I've watched shows on
the hurricane researchers that voluntarily fly into worse turbulence than any
commercial flights have ever seen. It feels physiological, because my body
just doesn't seem to care what my head thinks. I wish for sedatives or beta
blockers, or _something_. I can't temper my own fear. Average heavy turbulence
is no worse that riding a jeep on a dirt road, and nobody in a jeep fears the
vehicle is going to fly apart. (And by nobody, I mean me and imagine it's true
of everyone)

> I've still yet to jump out of a perfectly good airplane, but it's definitely
> on my bucket list.

It's way crazy fun. Dangerous but I don't regret my time skydiving even though
I don't do it anymore. If you spend some time in a wind tunnel first, you may
be able to get more out of your skydiving experience. Those weren't really a
thing when I was jumping, but now they're all over.

This is neither here nor there, but I never jumped out of a perfectly good
airplane. They were all crappers. One time I jumped out of a plane than crash
landed on it's return (pilot was fine). It might have run out of gas because
the DZ people are stingy, and not because the plane had a problem, but still
it was a dumpy ride, and most planes I jumped out of I'd rather have jumped
than stayed in for the landing. :P

~~~
bitmapbrother
It's interesting to hear that some people actually enjoy turbulence. You would
think that anything that introduces stress to aircraft components would be a
cause for concern when travelling in a metal tube with little chance of
survival in the event of catastrophic failure. Planes are reliant on routine
and properly thorough maintenance which isn't exactly a guarantee given the
time or cost constraints. And when you couple this with the fact that there
are planes flying that are very near their end of life expectancy how could
you not help but worry when turbulence hits.

~~~
gbacon
FAR 25.303 requires a _substantial_ safety margin for structural loads.

 _§ 25.303 Factor of safety._

 _Unless otherwise specified, a factor of safety of 1.5 must be applied to the
prescribed limit load which are considered external loads on the structure.
When a loading condition is prescribed in terms of ultimate loads, a factor of
safety need not be applied unless otherwise specified._

[https://www.law.cornell.edu/cfr/text/14/25.303](https://www.law.cornell.edu/cfr/text/14/25.303)

Airplanes in the United States are extraordinarily well maintained. Certified
airplanes (which include all airliners) must be inspected annually to maintain
airworthiness. Yes, you do hear stories of inspections sometimes being pencil-
whipped, but these are by far the exceptional cases. The inspection has to be
at least supervised (if not performed) and signed off by a certified Airframe
& Powerplant (A&P) mechanic with an Inspection Authorization (IA). The A&P
certificate requires training, passing a written knowledge test, passing an
oral grilling, and passing a practical test. The IA requires additional
training and testing. Someone with that much invested is not going to screw
around.

The annual inspection itself is detailed and thorough, not a quick eyeball.
Any discrepancies or issues (squawks) the A&P discovers are potential followon
work. Serious squawks _must_ be addressed before the airplane is airworthy,
_i.e._ , legal to fly.

Further, any airplane flown commercially (be it for flight instruction, aerial
survey, or transportation) must be inspected to the standard above after every
hundred flight hours. Commercial operators have special certificates to allow
them to conduct business that they likewise will not jeopardize by foolishly
cutting corners. Commercial pilots have hundreds or thousands of hours and
tens of thousands of dollars invested, so they also have a huge personal stake
in playing by the rules.

Turbulence is no fun. Catastrophic failure would be even less fun. Safety
rules, procedures, systems, and backups are in place that keep safety at the
forefront. The airplane can take it. People with significant stake personally
and financially have checked, rechecked, and signed off saying that it is
safe.

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WalterBright
It's well known that gripping the armrests provides lift to the airplane - the
tighter the grip, the more lift. So next time you experience turbulence, you
know what to do!

~~~
idlewords
This is a common belief, but it's not correct. You have to both grip and pull
upwards, otherwise the net lift is zero and you will die.

~~~
tritium
It gets even more complicated. If the plane suffers and inversion, as during
barrel rolls and loops, you have to coordinate pushes and pulls with the
orientation of the plane. Otherwise, the maneuver may suffer a distortion and
fail to recove properly!

~~~
acjohnson55
I hear it works better if you soil yourself. It helps smooth out the boundary
layer.

~~~
markdown
Am I on reddit?

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cmurf
This is bad ass. 777 wing test.
[https://www.youtube.com/watch?v=rak2HldVp9M](https://www.youtube.com/watch?v=rak2HldVp9M)

That amount of deflection is insane, you'd never see that in normal flight.
(Pilot here.)

The article mentions “turbulence penetration speed” or Vb and "maneuvering
speed" or Va. Simplistically these are speeds below which the wing will stall
before it breaks. The wing is designed to gradually stall in these conditions
not abruptly. You really won't feel it unless you know what you're looking for
and you're reasonably experienced as a pilot. The wing just kinda gradually
craps out rather than being over stressed, and just as quickly starts to fly
normally again.

Seriously the plane can structurally take extreme turbulence when flown at or
below the proper safety speed, even though by definition at extreme turbulence
the pilot is just along for the ride (the plane is not considered controllable
with extreme turbulence, you get to pick a speed and kinda sorta a general
direction, you don't get to control the altitude or the attitude). I've not
experienced extreme turbulence and have no desire to, but have been in severe
turbulence and don't need to do that again. But the plane is alright.

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4ad
Another fun fact, 99% of what people consider bad turbulence is less bumpy
than the average bus ride. It's just that being in the air messes with the
subjective importance people assign to turbulence.

~~~
dahart
This. I know it, and you're right, flying makes it feel worse. It helps me a
little when I'm in flight turbulence to close my eyes and pretend I'm in a bus
on a dirt road. But I can't figure out how to ignore it or just feel calm and
rational, like I want to.

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dkbrk
Microbursts
([https://en.wikipedia.org/wiki/Microburst](https://en.wikipedia.org/wiki/Microburst))
can be very dangerous. I'm not sure if these would be correctly classified as
"turbulence", though.

~~~
peteretep
I was on a wide body a few months ago and we had a very sudden burst of pretty
intense turbulence -- we'd apparently hit the wake of an A380

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bfrog
I've been on a smaller jet where on approach to O'Hare, banking left over the
lake, we must've hit a aircraft vortex. We went from maybe 20-30deg bank to
something close to 80 in an instant while simultaneously getting that lovely
zero g feeling if falling. Lasted like the article says maybe only a few
seconds but I'd be lying if it didn't get my adrenaline going and a few
expletives out of me.

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bigdubs
My favorite explanation (though not comprehensive) was in The Hunt For Red
October: [https://www.youtube.com/watch?v=htTLYO-
zOww](https://www.youtube.com/watch?v=htTLYO-zOww)

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cmurf
I like a bit of "chop" (light to moderate and rhythmic turbulence). I really
really do not like phugoid oscillations on an international night flight over
the north pole. That was pretty creepy.

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gerbilly
Turbulence in flight might not crash the plane, but do sit down and wear your
seatbelt when advised to.

A sudden drop of 40 feet can propel you upward toward the ceiling and break
your neck.

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nunez
This is a straight rip from Cockpiy Confidential, which was a really great
book

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geff82
As someone very much interested in flying, I find this article perfect.

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Animats
If he could explain turbulence, that would be good for a Nobel Prize.

~~~
ridgeguy
Yep. Supposedly, Heisenberg thought the explanation of turbulence worthy of
putting the question to God. And didn't expect an answer to be forthcoming.
[1]

[1]
[https://en.wikipedia.org/wiki/Turbulence](https://en.wikipedia.org/wiki/Turbulence)

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averagewall
A bit of a tangent, but a comforting thought is that unusually strong
turbulence counterintuitively has a beneficial effect on fatigue crack
propagation. Aluminium always has cracks and they're keep growing but a heavy
load that opens up a crack plastically deforms the material around the crack
tip so that its natural state is for the crack to stay open. But the rest of
the structure forces it closed. Once it's in this state, subsequent smaller
higher frequency loads don't apply the usual damaging tensile stress to the
crack tip so it doesn't grow like it otherwise would have.

Not going to stop the wings falling off on your flight though, but it might
help the next guy if it's some South American airline that never maintains its
planes :P

