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Unplanned Freefall? Some Survival Tips (greenharbor.com)
336 points by Tomte on March 10, 2017 | hide | past | favorite | 184 comments



> 120 divided by 5 = 24. Not bad! 24 mph is only a bit faster than the speed at which experienced parachutists land.

This is of course being a little silly, but it does get the physics wrong. Your energy is proportional to the square of your speed, so you have 25x more energy to dissipate at 120 mph, not 5x. Even if your five point landing was perfect, each of the five 'hits' is the equivalent of a landing at just under 60 mph, not 24.


My intuition rings false on this -- I don't think this is right. In a vacuum, ignoring the rocket equation (that is, assuming ejected reaction mass is negligible compared to projectile mass), the energy required to produce the 120 -> 96 mph change is the same as that required to go from 24 -> 0. This works out in conservation of energy because the ejected mass has kinetic energy of its own.

In the case of you landing, I don't think energy balance is the way to look at it; each of the collisions that slows you down will transfer some energy to the ground. In terms of force, the force is dependent only on the acceleration, so it comes down to how long each impact lasts. If each "bounce" or "thud" lasts the same amount of time (I don't know if this is realistic) then each one will transfer 1/5th of the force, as the article says.


Your intuition is wrong.

Potential energy is linear with height. AKA it takes the same energy to climb from floor 1 to 2 as 2 to 3.

Gravity is 32 feet per second per second aka you gain speed over time. In a vacuum 0 to 32 feet per second takes 1 second, 32 to 64 feet per second takes 1 seconds, 64 to 96 takes 1 second etc.

However, in the first second you fall 16 feet. in the next second you fall 38 feet because you where falling at the start of that second. Thus, it takes more energy to increase your speed.

PS: What's confusing about rockets, is your fuel has momentum. So, when use it your consuming the energy it took to get that fuel up to speed with you. Further, at low speed most of the energy goes into the exhaust not the rocket.


>However, in the first second you fall 16 feet. in the next second you fall 38 feet because you where falling at the start of that second. Thus, it takes more energy to increase your speed...

Doesn't make sense. Care to explain? Are you saying it takes less energy to take an object from 0 to 10m/s than it requires to take it from 10m/s to 20m/s?


That's exactly correct. Consider the equation for kinetic energy:

    E = 1/2 m*v^2
The energy to go from 0-10 m/s is the difference in this value (for 1kg e.g.):

    dE = E1 - E0 = 1/2(10^2) - 1/2(0^2) = 50J
To go from 10m/s to 20m/s:

    dE = E2 - E1 = 1/2(20^2) - 1/2(10^2) = 200 - 50 = 150J
In fact by solving for velocity you can figure out what happens if you put another 50J into your object that's already going 10m/s:

    v = sqrt(2*E) = sqrt(200) = 14.1m/s
When you double the energy, you only get 1.4 times the speed.


Uhh, that's just what happens it does not need to make sense.

You can find plenty of examples but that's about it. Ex: You hold a gun in your hand and shoot it, the gun kicks back because momentum is concerved. But, the bullet is a lot more dangerous than the gun because while it has the same momentum it's got a lot more energy. Now, it hits a bullet proof vest. The vest still hits the person wearing the vest but because it obsorbed the energy it feels like a strong punch instead of making a hole in them.


Suppose a 10 m/s gust of solar-wind accelerates a space-balloon from 0 m/s to 10 m/s. And suppose I want to further accelerate the balloon from 10 m/s to 20 m/s.

A second gust at 10 m/s is NOT enough to further accelerate the balloon to 20 m/s. Because the wind and the balloon are now travelling at the same speed. It follows intuitively that the second gust should contain more kinetic energy than the first gust.


Thats correct, it actually does. Somewhat counterintuitively. Some explanation at https://www.reddit.com/r/askscience/comments/40bi9z/why_is_t...


It makes more sense to ask "does an object moving 20m/s have more energy than the same object moving 10m/s?" The answer is obviously yes; so how much more?


Since KE = (1/2)mv^2 we can just do the math.

Say m=2 so we're just left looking at the v^2 terms:

120^2 - 96^2 >? 24^2 - 0^2

5184 >? 576

So yes, the KE difference between 120 and 96 is greater than the difference between 24 and 0.


doing the math is seldom enough ;)

*KE == kinetic energy

kinetic energy: "energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes."

in normal person terms: the energy of moving, or ~exercise, in a parallel world :)


The answer is that you gain velocity by shooting rocket fuel out the back. The energy that the fuel loses is proportional to the the square of the speed of the rocket as well, so everything works out fine. The mass of the rocket fuel is small, but it's not negligible, especially considering that kinetic energy is far more concerned with velocity than with mass.


The article is humor. Let's not get too technical on the math. Of course you're going to be a pancake if you hit the earth at 120mph, even if you find a way to split the damage 120 ways.


I recall the advice of Jack Handey [1] [2]:

> “If you ever fall off the Sears Tower, just go real limp, because maybe you'll look like a dummy and people will try to catch you because, hey, free dummy.”

[1] http://www.deepthoughtsbyjackhandey.com/

[2] https://en.wikipedia.org/wiki/Jack_Handey


Better advice is to try and fall on a moving car roof like this unfortunate window washer in San Francisco recently.

http://ufpnews.com/window-washer-survives-11-story-fall-onto...


SENATOR Jack Handey


Jack Handey is an actual person, the writer of the one-liners GP refers to: https://en.wikipedia.org/wiki/Jack_Handey (I'm not sure if he recorded the voiceover performance or not). Al Franken is a different actual person who also worked on Saturday Night Live and who is now a US Senator.


Handey also wrote and narrated “Deep Thoughts” and “Fuzzy Memories” for the show.

http://www.deepthoughtsbyjackhandey.com/the-answer/


..? Jack Handey != Al Franken


Without checking the interweb, isn't Stuart Smalley == Al Franken?


Al Franken - Real person, writer and cast member on SNL, Senator.

Stuart Smalley - Character played by Al Franken.

Jack Handey - Real person, writer on SNL, did Deep Thoughts voiceovers.


Yes, that was one of his more notable characters.


TIL!


I'm pretty sure they are the same person. Lookup Al Franken.



You're right. I'm mixing up Stuart Smalley and Jack Handey.


No. Jack Handey is the name of a real comedian and he read his own stuff on SNL.


> 120 divided by 5 = 24. Not bad! 24 mph is only a bit faster than the speed at which experienced parachutists land.

Better yet, just put your hands in front of you and land on all ten fingers. Then it's only 12mph. /s

In reality your entire body is moving at 120mph, so you can't divide the forces in this manner. This a PSI problem. Total inertia distributed over a given area. And the results are much less favorable.


As sfeng describes in another comment, the math isn't right, but the concept does make sense. It doesn't negate what you're saying either though; the 5 point landing is basically a way of distributing the force over as much area as possible. (You can't accomplish the same thing by just landing on your side, because the mass of your body isn't evenly distributed across the surface that would contact the ground.) It does manage to distribute the force over time a bit too, which is also beneficial, but a less significant effect.


Protip: Put your non-dominant hand over your dominant hand instead of locking your fingers together. That way if something falls on you, your dominant hand won't be crushed.


Excellent read. Just a few more pointers from personal experience. When over water, "pencil" your body, feet first, at the very last second. Molecules of atmosphere, which are your friend at 120mph, are not so much when they are of water.

Also the author didn't mention my favorite survivor Juliane Koepcke. https://en.m.wikipedia.org/wiki/Juliane_Koepcke


I've never been on the offshore survival course where they teach you how to jump off an oil platform into the sea and survive, but allegedly they tell you to cover your mouth firmly with the palm of your hand and pinch your nostrils closed tight between your thumb and fingers. Apparently when you hit the cold water your natural reaction is to breath in. Also, you must prevent water being forced up your nostrils and damaging your brain etc.


This is what the Marine's teach when they abandon ship http://www.survivalscout.com/guides/terrain/ocean/abandoning...

Basically cross your arms, legs and look forward


I tried this on a ~60ft cliff jump and punched myself in the eye. Also got the wind knocked out of me


I'll stick with drugs thanks, sounds much safer


Maybe use your elbow? It's not a perfect cover, but it's impossible to hit yourself.


I can't help but think this would get your shoulder dislocated or lats torn.


I have been. You do get to practice that jump off of a moderately high diving board, I forget exactly how high it is. But it's legs together, feet pointed down, one arm with the hand over your face pinching your nose and the other held tight to your stomach. Nobody mentioned doing anything special on entering the water, besides the obvious of swimming to the surface after you stop.


Not so different than avalanche survival, then. If you can't avoid going under, protect your available air when you do.


The thing that kills most people who are "simply" buried in an avalanche (and not pulped as they're carried through the tries or into a rock) is actually the CO₂ concentration in the snow around their nose and mouth building up over time.

I have a piece of avalanche survival kit made for skiers/snowboarders called the "AvaLung" in my off-piste bag. It draws air in from around the face, and vents your exhalations out behind you. People have survived being buried an hour or more wearing one of those.


I’ve also seen cliff divers saying to clench your buttocks as tightly as you can; apparently it helps keep your legs rigid so you don’t knee yourself in the face, and may reduce the likelihood of internal injury from impact to the perineal area.


Or a forceful enema.


I immediately thought of her too. She tells her story in Werner Herzog's "Wings of Hope": https://www.youtube.com/watch?v=rlJVIcCPIl8


Another key thing is to open your legs soon after entering the water to slow your decent. Don't stay in that pencil position or you're likely to go deeper than you really want to.


> The perfectly tiered Norfolk Island pine is a natural safety net

When I was child I used have fun by climbing to the top of conifers behind our house to sit on the highest branch and just slide down

Each successive tiered limb would catch the bend on the ones above and I would slide down perfectly fine


Children genuinely are constantly trying to find unique ways to kill themselves.


A similar tree saved my uncle's life when he fell (drunk, stoned?) off a cliff once twenty years or so back. He did get stabbed by one branch, but overall a better outcome than a straight 100-150' drop to the stony ground below.


Speed skiers go over 150mph, versus 120 for a flat-oriented free falling person. It's conceivable that orienting yourself to slide down a groomed black diamond ski run could be a winning strategy, too.


Maybe you should target a steep avalanche terrain with fresh snow. Not only you have a hell of a ride while falling down, you get to enjoy a ride in a snowy feather all the way down the valley! Don't forget to mount your GoPro while boarding!


>Don't forget to mount your GoPro while boarding!

Man, I wonder if we're going to end up seeing someone's free fall smartphone video someday. Not everyone is going to read this article and be prepared to survive like we now are, so what if they decide to use those couple of minutes falling to try to record a message to their loved ones? The audio would be blown out but I don't see why the camera wouldn't continue working. That would be quite disturbing to watch.


Potentially NSFW / terrifying videos:

Multiple gopros record an in-air collision of skydiving planes: https://www.youtube.com/watch?v=7p6hqMnsLFY&list=FLR2K9vyQEB...

Tangled chute: https://www.youtube.com/watch?v=ciIjdvNo65s

I can't find it but I've seen two more videos of people who have survived near freefall after parachuting accidents. One became a paraplegic IIRC.


> Man, I wonder if we're going to end up seeing someone's free fall smartphone video someday.

Undoubtedly, since it has with other kinds of video cameras: https://www.youtube.com/watch?v=hFSp-SRGhNs

"I'm dead. Bye." (He was not, amazingly.)


that would speak to the debris you possibly grabbed on the way down. Use that piece of fusilage, seat or luggage as a sled and work those bank turns


I've just got an idea for a new smartphone game! :D


Except then you're stuck in freezing temperature, with what is probably totally inappropriate mountaineering gear and odds are you've got an avalanche to dig yourself out of.


Aim for the bunny hill instead?


Same with MotoGP riders. They basically slide and then they have gravel/sand catches around the turns they are most likely to fall off. Sometimes they tumble. It's not pretty but it does the job most of the time. But, it's also perpendicular. So if you're in a desert, aim for the top of a large sand dune, try to get your perpendicular velocity as high as possible.


> Sometimes they tumble.

As someone who has actually done that, tumbling is really bad. The titanium artifacts in my foot and leg are a permanent reminder of it.

Stick to plain sliding and trust your leathers.


Which is fine, except when the seams split due to the stitching disintegrating, and you end up with a large friction burn.

I needed a skin graft.


Or the jacket double-backing over, exposing the skin. I lost half-pound of skin & flesh to it. Didn't get the graft though.

PS: That's waaay better than tumbling...


What happens if a speed skier tumbles?


Pretty much what you'd expect - massive injuries, sometimes death. Search Youtube for "speed skiing crash" for examples. Sometimes people get lucky and just slide to a stop, depends on how they fall.


Sliding can lead to burns.


No idea, but remember that their speed is parallel to the surface, not perpendicular.


Interesting that the overall advice here is "Don't Panic"

Also interesting that having a towel could be incredibly useful in this situation.


Since we're quoting Doug Adams: “The Guide says there is an art to flying", said Ford, "or rather a knack. The knack lies in learning how to throw yourself at the ground and miss.”


"Oh no, not again." -A bowl of petunias.


Yet another reason to always know where your towel is :)


There is a DNA joke in there somewhere.


Oh, so that's why South Park has been telling us to bring a towel for all these years!



Ouch. Nice move for Americans to fly in France where healthcare is affordable. If you did this in the US as a tourist you'd likely be broke for the rest of your life.


Make sure to go back to your home country as fast as possible, and then just ignore the bills. They'll have a very difficult time collecting on a debt in a foreign country. Don't come back to the US as a tourist after that.

This reminds me of college, where sometimes the police would come looking for students who were foreign nationals, because they had gotten credit cards and then racked up huge balances buying stuff, but didn't bother paying the bill. When the creditors tried to have them served, it turned out they had already graduated and left the country. Good luck getting some guy in Indonesia to pay off his US credit card balance. What were these creditors thinking?


> Make sure to go back to your home country as fast as possible, and then just ignore the bills. They'll have a very difficult time collecting on a debt in a foreign country. Don't come back to the US as a tourist after that.

Actually if you have a credit card, you might have a travel insurance as well. So no need to ignore the bills. And in France it's not like in US where the first thing they ask you is the name of your insurance company, even if you're bleeding to death.


>And in France it's not like in US where the first thing they ask you is the name of your insurance company, even if you're bleeding to death.

I was talking about a scenario where a tourist to the US goes to a US hospital and racks up a lot of medical bills.


Sure, but it goes both ways, a tourists NEEDS an health insurance to travel to US. I'm pretty sure it's necessary even for those who benefit from the VISA waver program.


A post-mortem from a base jumper? Those can't be common...

As someone who participates in a reasonably-dangerous / reasonably-uncommon hobby, that discussion really resonates with me. So much in there to contemplate.

Thank you!


At the end of that article, the jumper who survived impact says: For those who want to be the next Graham Dickinson, cut no corners.

Graham Dickinson died in January.

There's a blog entry that addresses that aspect:

http://topgunbase.ws/experience_doesnt_mean_shit/

>> Inexperience kills our new pilots.

>> Complacency kills our high-time pilots.


You could shorten that to: jumping off rocks without a parachute kills. Father of two engaging in this? Moron.

If you're young, you have no dependents and you feel like life probably isn't worth living then go for it, otherwise better not to pretend that you are a bird, you aren't. Birds have lots of options, wingsuit flyers (all terminology and pretense to the contrary) are not flying as much as they are falling and gravity has no mercy.


I don't understand your comment. They are all wearing parachutes.


Well, ok strike that. Make it 'pretending to fly close approaches to solid objects without much in terms of alternates when things go pear shaped'.

There is a fairly good reason why proximity wingsuit flyers tend to have a limited life span.

Whether or not you wear a parachute is not very important once you impact a tree or a mountain at high speed.


It's definitely a super-dangerous sport, but I know a few guys who have been doing this for a long, long time and understand the risks and keep their egos in check. They have a plan and they have outs. When done right, you are diving hard at the terrain to stay attached to the line, so if anything goes wrong you relax and separate. Some of these people have kids. None of them are morons :)


My personal philosophy admits the fact that this life might just be a training camp for another life.

Hence, all the information learned in this one will be useful at some point in this or another life.

Now I don't know what to do with this information .. I don't want to need it..

And then if fate really leads me to fall from a plane, I will definetely remember this article which will seem infinitely funnier in mid flight.

Heck if I don't hit the ground laughing my ass off !


> My personal philosophy admits the fact that this life might just be a training camp for another life.

Makes me wonder if annihilation is possible in the future life, but not this one.


If you live N lives then the chance that this is the first is 1/N. I don't know about you, but I don't remember anything from any previous lives, so it seems to me there's a (N-1)/N chance you don't get to remember anything from previous lives anyway.


It could be a question of soul distribution, though; if you can only have one ghost in each machine, and there's the potential for a spacefaring civilization to expand to many, many planets in the future, then it's possible that the 50 or so billion people who have lived since humanity's birth represent only a sliver of a fraction of the total number of souls needed to staff a well-stocked universe. So we could potentially be heavily weighted towards most people being on their first go-around if we have the potential to make it that far and souls or selves or whatever are actually scarce enough to be re-used.


No. All of the reality as we know it is just a software bug, with the fix request sitting in some junior developer's project management system. They just haven't gotten around to submitting a pull request yet.


That's reasonable.

I also find it interesting that all the information in our DNA and what our body does with it is a form of 'remembering' what has been transmitted from previous lives, right ? :)

What if, in a similar way, what we learn here is compressed and optimized for next lives - things that are called 'talents', 'instinctual knoweldge', 'natural gifts', etc.

There's also no guarantee that past or future lives happen in the same type of body (or same planet or even same Universe).

Maybe it's an Eagle next time, who knows ? ;)


The great stack overflow in the sky.


Ah yes, everyone wrestling with endless questions while the front gate is deserted.


Seems like it would be a heap overflow though.


That depends on one's theological commitments, no?


Something about your philosophical approach made me LOL and think of this poster: https://cdn.shopify.com/s/files/1/0535/6917/products/mistake...


A man jumps off a 20 story building. As he passes an open window on the 6th floor, people on the floor hear him exclaim "so far, so good!".


You might get lucky like the guy in the Hudsucker Proxy!

Spoiler warning: https://www.youtube.com/watch?v=P52eqNKCpYc


I don't get it


I suppose it's a quote from La Haine (1995) http://www.imdb.com/title/tt0113247/

> Heard about the guy who fell off a skyscraper? On his way down past each floor, he kept saying to reassure himself: So far so good... so far so good... so far so good. How you fall doesn't matter. It's how you land!


I remember hearing it from Steve McQueen in The Magnificent Seven when I was a kid https://www.youtube.com/watch?v=V7GP3l5znc8


"Jusqu'ici tout va bien"

It sounds so nice in French.

Amazing film, by the way.


The measure of success as a function of how far you've fallen is basically constant throughout and then suddenly changes to 0 (or -inf, or whatever).


Maybe the Heaviside step function would be fitting :-)


It's more like the delta function/"function" restricted to the nonnegative reals.


Ages ago (early 1980s) I read a magazine article about the minds' adaptation when falling. The article posited that the brain kicks into high gear and time subjectively slows down for the faller, enabling them to take action to save themselves.

The article had several first-hand accounts of people who had fallen off cliffs, wagons, and the like, and one skydiver who survived impact by landing in a muddy ditch. The article was especially interesting since I was a skydiver at the time and all of us jumpers could relate to the feelings described. Not only that, but the one skydiver interviewed had jumped at our drop zone and was known by most of us.

Sadly, I can't remember where the article appeared. I think it was Smithsonian Magazine but I have been unable to locate a reference online. If anyone else locates it, please post.


I remember reading about some experiments done on this where the result was that the subjects just remembered the experience in more detail, and didn't actually experience time slower. Something about looking at something that changed just slightly faster than the maximum speed someone can normally see changes in something, while freefalling.


That makes sense - high adrenaline causing extremely high resolution for memory write, but later the playback speed on a read is the same, so it seems slower when really it's just more detailed / takes up more tape.


I remember hearing about that as well, likely from a Radiolab or This American Life podcast (can't find it right now), but http://www.npr.org/templates/story/story.php?storyId=1291121... talks about it a bit more.

LT;DR, people didn't actually experience time slowing, they just happened to remember more of what was happening.


I experienced this a few years ago descending a hill on my MTB I hit a patch of black ice and crashed I can clearly remember looking at the car close behind and having time to think is he going to hit me


I had this happen in sparring, over ten year of training martial arts and that happened only ever once, but man it was awesome.


I've written a longer, more detailed comment in this thread, but long things are hard to remember so I decided to condense my advice into a paragraph:

Falling from a plane, you have a minute to land after waking up. You can move laterally 2 miles by controlling your body. That gives you 13 sq miles to land. In this order, aim for: snow, swamp, glass skylights, large bushy trees (but not redwoods.) Water is almost guaranteed death. Stay "flat" until right before impact, and move to a standing position. Relax and go completely limp. If you follow this advice your odds are good.

My more detailed comment, with sources/numbers, is here: https://news.ycombinator.com/item?id=13840660


Glass skylights, really? Not disputing it, but what's your reasoning? Slowing you down while still breaking before you do?

Also, regarding water: while I've heard the standard comment that hitting water can be as bad as hitting concrete, that seems like it would apply more if you have a larger surface area. Divers can dive from 35+ meters, and hit at 60+ mph, without any injury at all. If you are capable of aiming and landing feet-first and remaining as streamlined as possible, would water still be a fatal option?


Yeah, glass is actually one of your better bets. Two of the 5-15 survivors of free fall incidents fell through glass roofs. You can read more here: https://en.wikipedia.org/wiki/Alan_Magee

The problem is that you're hitting water at 120mph. A 60mph impact of a 50kg person is 35kJ; a 120mph impact of a 50kg person is 150kJ. That's 4.5 times the energy. I'd almost certainly choose water (with a streamlined, pencil dive profile) over concrete, but that doesn't mean it's not going to be far more fatal than any other options.


Nitpick: doubling the speed should merely quadruple the energy, 4.5x is too much.


The water/concrete thing is just a simile, not a statement of fact. It's not meant to be "hitting water at X speed is like hitting concrete at X speed" - otherwise we'd have a lot of dead high divers on our hands. It's just meant to mean "hitting water at high speed isn't very forgiving".

https://youtu.be/yGJqqDaKscQb - 'Mythbusters for the Impatient' video showing dropping a pig onto concrete vs water. The concrete drop actually decapitates the pig!


...and if you have to hit water, close you mouth, hold your nostrils closed, and clench your buttcheeks together. Basically, you need to close all holes into your body that are aligned in such a manner with the water - it will force its way in greatly. The last tip - do that because you don't want a ruptured bowl/intestine...


If you hit land and survive, you passing out will (probably) not leave you any worse off. If you hit water and survive, you need to remain conscious and be able to move enough to swim somewhere/to something.


"Water is almost guaranteed death"

But let's say you are still strapped to your airplane seat, or you can grab hold of another large object and ride it. Are your chances of surviving better landing in water or on ground?


Hmm, in that case, wouldn't it be reasonable to try to somehow throw this extra object under you so that it breaks the surface tension before your fall?


Reading this article brought back memories when I was getting training to go solo skydiving. The first day was all theory and drills in the classroom.

In all my years at school, university lectures, and work-related training workshops, that one day of skydiving class remains the only time in my life when I was 100% completely focussed, awake and attentive for every subject.


Having jumped out of many airplanes, I've thought about this and how to survive on occasion. But temperatures at 35k are often like -50 degrees. At 500mph decelerating down to 100mph, it seems like there's a good chance you could become a human snowflake long before you hit the ground. :P


A friend of mine once said that if you keep your lips puckered up, and force yourself to breathe through a tiny hole, you increase the air pressure in your mouth and lungs, which is useful at a high altitude. I don't have a thought at this moment how to test this as I sit hear at sea level. Any idea if this is true, or partially true? I didn't see anything about this in a quick Google search.


Seems doubtful this would have any significant effect. You can only create about 0.1 bar of overpressure with your lungs on exhale.


You clamp your eyes, mouth and other orifices firmly closed.


I had always heard that being unconscious was the key to surviving an extremely long fall (relaxed body doesn't tear itself apart on impact). I can't find the story of a boy who was picked up by a tornado who was tossed out from hundreds of feet and survived without any injuries, it was attributed (in the show I was watching) to his having passed out and that his body was relaxed.


Depends how you land. Being unconscious, you can't really control how you land, so I'd take the conscious route instead.

But if you do pass out, your muscles will be relaxed and offer more give in absorbing the force of your body. Ideally you'd land on your feet, let you entire leg basically collapse and break, bones flying everywhere, and maybe you'd have a chance to live. Land on your head, chest or any other area with vital organs...being unconscious will not do anything for you.


Might be best if you've a long fall: hold your breath until you pass out (children can do it, I assume adults can too). Saves the lengthy torment of a long fall, possibly increases chances of survival?


I've seen someone fall off a cliff (30m I guess?) and survive. He was drunk.


Injuries?


I wonder if you could grab the center aisle life raft on the way out. If you could keep it under you after inflating it, not only would it provide more surface area and so a slower terminal velocity but it would also absorb energy when you hit by popping and create a wider deceleration profile so limiting the g-force of the impact.


If you're supernaturally calm and skilled, it will also give you more steerability. You might even be so lucky as to be able to aim for a stand of pine!


Or an angled snowbank. :D


As a skydiver I would admit that the content of this article is a time-wasting bullshit. Here is a real world scenario:

1) you'll knock out either because of lack of oxygen or because of a violent spin

2) you'll freeze to death

3) you won't be able to position yourself properly or fly in a particular direction because of lack of training, so you'll hit the ground at a random place so hard that you'll die.

What I would do is flip to my back not to shock myself with the view of the earth coming at 120mph, relax and wait.

Towel huh. The speed difference is so big, that you'll never see a towel, that happened to fall off the same airplane as you.

There was a case in Russia not so long ago when a cameraman, who happened to be a very experienced skydiver, fell off a helicopter. He managed to drive himself towards a pond but died immediately because of water impact. The hit was so hard that his jumping suit was almost stripped off his body.


One thing I've been curious about for a while: would it be possible to survive free fall into water if equipped with a sufficiently long spike-shaped "base"? The sharp part of the spike, which would probably have to be 100+ ft long, would be oriented so that as it entered the water it would displace more and more water, reducing the g-forces experienced by the spike, and you atop it.

A few improbable things would need to also hold: 1) Spike would need to stay straight as it entered the water. 2) Spike should not significantly increase terminal velocity, at least not for most of the descent

I think (?) it's doable, but would be fun to see the physics worked out. E.g., how long should the spike be? What should be its shape? How could it be kept maneuvered into the right orientation for entering the water without significantly increasing terminal velocity?


I always been curious about surfactants and whether you could throw some underneath yourself in a free fall to break up the surface tension in a splash landing.


Then today's your lucky day. Mythbusters did a bit on exactly this, i.e. if you're holding a hammer and about to fall into water, whether throwing it ahead of you will break the surface tension and save your life: https://www.youtube.com/watch?v=oCSQExxWulU


This is very useful information. They should have this guidesheet in every airline seat back.


I'm sure that would go over really well.


I kind of want to free fall to test this out now. I feel kind of prepared.


I worked on a hardware product that shipped for the Xbox 360, and it had an accelerometer.

I wanted to add a game achievement for "30 seconds of free fall". Achievable on something like the Vomit Comet. Going for 5 minutes of free-fall would have required something like a rocket. Nobody liked either of my ideas :-)


I'm sorry to be the voice of gloom and doom, but this was the money quote for me: "Thirty feet is the cutoff for fatality in a fall. That is, most who fall from thirty feet or higher die" Holy crap, only thirty feet? We are all going to die.


Well-written but a bit light on information. I thought about this a while back when I had the chance to try free-falling in an indoor wind tunnel.

You can control four variables: your speed, your landing position, your landing orientation, and your muscles.

- Increase your surface area as much as you can, that's your only way to slow down. Best case scenario you'll find a parachute, put it on, and slow down to 25mph or so; worst case, you'll manage to point yourself in a bullet shape and hit 200 mph. Realistically you'll go into a "flat" position and sail along around 120mph.

- Make yourself "flat" until you're about to land, then position yourself such that you land feet first.

- You can move, as the site said, about 2 miles horizontally falling from 15,000 feet: aim for trees, a heap of soil, or snow if possible. If you know the area, aim for any buildings with a large glass skylight - that's saved two known freefallers [0].

- Relax your muscles as much as you can. This can greatly improve your odds. By "greatly improve your odds" I am not kidding: this is almost definitely the single best thing you can do, and being fully relaxed can make you half as likely to die. [1]

There's also a very good possibility you're not at 35,000 feet. For example:

- You fall off the Burj Khalifa, 830 meters high. You'll fall for about 20 seconds, the last 5 or so near terminal velocity. Use your body to move and aim for the trees near the base of the tower - you've got enough time to make it, easily.

- You fall off a very tall building, ~500 meters or so. Same as the Burj Khalifa but you have less time, so think fast.

- You fall off a shorter building. There's no time to maneuver or slow down. With the few seconds you have, point your feet down and relax.

If you're over water, your odds are very low. The best option is to go in feet-first like a pencil dive.

Remember, you _do_ have an OK chance at survival. Between 5 and 15 people have survived free fall, most of which did not know what to do. From 15,000 feet up, you can land wherever you want inside a 13 square mile area - 2 miles in any direction. That's probably enough to get you to some trees at the very least. You can draw that on a map with this tool [2].

You can seriously improve your odds of survival by following these steps. Landing on snow, or a swamp, or a glass skylight makes your odds quite good. Landing in trees makes your odds OK. Making yourself flat gives you more time, and grabbing onto debris - if you can - can increase your chances of survival by 5 times [3]. Then, simply relaxing can double your chances of survival.

Finally, once you've hit the ground - regardless of what you did - there's a decent chance you're still alive, even if you'll die soon. Spend a short amount of time to stop external bleeding, keep your wounds clean and contact emergency services as soon as you can - ultimately, they will know far better than you what to do.

[0] https://en.wikipedia.org/wiki/Alan_Magee

[1] http://dx.doi.org/10.1016/j.alcohol.2012.08.006

[2] http://obeattie.github.io/gmaps-radius/

[3] http://www.popularmechanics.com/adventure/outdoors/a5045/434...


So, stupid question from someone who has never gone skydiving or anything of the sort: how exactly does one "move" laterally?

I imagine it's by deflecting various parts of one's body, using them in a manner akin to flight control surfaces. But which ones? What's the short version for idiots?


The tracking position - face-down, straight legs, arms by your side - lets you move head-first at very high speeds. There are claims of achieving a 1:1 glide ratio. https://en.wikipedia.org/wiki/Tracking_(skydiving)

As a student I've mistakenly jumped out of a plane quite far from the DZ and managed to track most of the way back during freefall (and flew the rest under canopy).


The last sentence reminded me of the hitchhikers guide to the galaxy for some reason.


In that case you'd just point your feet down and miss ;-)


Doesn't surviving any landing guarantee you'll be disabled for life?


Vesna suffered a lot of injuries, but recovered completely: https://en.wikipedia.org/wiki/Vesna_Vulovi%C4%87

> Vulović continued working for Jat Airways at a desk job following a full recovery from her injuries.


And not surviving means you'll be flying for the rest of your life!


No, some of the survivors have long falls have done so with very little injury, and several had severe injuries but fully recovered from them.


If grabbing onto debris can increase your chances of survival 5x, why eject from your seat, which presumably qualifies as debris, in the first place?


You want to minimize weight and maximize surface area, as well as increase impact time. If you're given the option to hold onto a giant piece of extra-strong pinkboard with grip handles, that'd be ideal.

Unfortunately, this debris usually means you give up control, so it's a tradeoff you have to make. If you're over the middle of the ocean and two miles of lateral movement won't help you, by all means stay with your debris. But if you're falling over a mid-sized city, you have lots of things beneath you: buildings with glass skylights, piles of snow, and occasional trees. Landing on any of these things is far better than staying with whatever object you've got a hold of.


If you are hanging onto a piece of debris, do you want to try to let go of it before impact? I'm assuming it's something with more drag than you, so presumably you're hanging under rather than surfing on it..

Although that's another interesting question. Maybe there's debris that wouldn't be particularly useful in slowing your descent, but could be useful to break your fall on impact... I can't immediately think of something that would be sufficiently good at that that it would be worth carrying with you though.


An airbag?

Unlikely to find one in a plane, though.


They do have inflatable life rafts. Might make a decent parachute too, but given their size would be tough to get it oriented and hang on.

Inflatable life jackets too, but those probably wouldn't be substantial enough to make much difference. (Although probably better than nothing if you could manage to actually don and inflate one while falling.)


Terminal velocity is the balance of force from gravity applied to weight, against force from air against surface area.

So the better that ratio the slower you fall. An airplane seat is heavy (lots of metal) but the surface area is about the same size as you.

The cushions could be useful if you can hold them in a way that adds surface area (i.e. not against you), but not the frame which is heavy and dense.


> Relax your muscles as much as you can. This can greatly improve your odds.

So, basically your legs become a crumple zone.


If you have enough time, would it be worth it to take off your shirt or other clothes and try to use them as a parachute of sorts?


Almost certainly not. I've been in a vertical wind tunnel before and taking off clothes would be quite difficult and take up a lot of your time - remember, unless you're some kind of superhuman and/or spent your life on top of Everest, you're going only be conscious for about a minute. Taking off your shirt will also probably make you even colder than you already are, which definitely won't help with relaxation (which is by far the most important thing.)


What about your clothing? Can you use it to increase your surface area?


Great read! I must admit, I have thought about this a few times in the past when I was on an airplane and thought what would I do if the plane split in two and thought about some of the things the author mentioned.

One more tip, always wear the largest rain coat you can find onto the plane and keep some nylon rope in one of the pockets so you could fashion a parachute on the way down :)


Fun read.

Has anyone actually survived an unplanned free fall like this?


It was only occasional free-fall, but William Rankin's story of ejecting at the top of a giant thunderstorm is still one of the craziest "fall out of the sky" stories I've ever heard: https://www.damninteresting.com/rider-on-the-storm/


The article mentions a few people, including Vesna Vulovic who holds the Guinness world record for surviving a free fall at 33000 feet.

https://en.wikipedia.org/wiki/Vesna_Vulovi%C4%87




The site itself has a page of freefall survivor stories. Links at the bottom.


That was a very excellent distraction


How easy is it to control your body's attitude during a free fall?


Belly-down is the easiest and most stable attitude, which is why that's the first attitude taught in skydiving.

The other common attitudes are head-down vertical, feet-first vertical, "sitting", and back-flying. The first three have a much faster fall-rate than belly-down, and are less stable. Backflying isn't quite such a difference in fall-rate, but is still harder to learn, and less stable.

How easy is it to learn? Well, unless you've skydived before, then you get around a minute to learn from scratch. Good luck to that!


It's easy if you know what you are doing. It's not a steep learning curve but there is one.


Great article, reminds me of the same writing style used by the author of the Rotten Library (which, by the way, is still a great read).


> If you have ever tried to keep your head when all about you are losing theirs

because there aren't any around to blame it on you? :)



Just curious, could clothing help you create something like a paradise? For example, a hoodie held by sleeves?


You need to hold it by at least three points, otherwise it will simply flop upwards like a flag. Your toes can't curl hard enough to hold onto a piece of fabric being pulled by a 120 mph wind, so the only way to make a sail is with your hands and your teeth. If you have a button-down, you can hold the corners at your sides to make a shitty wingsuit. I suppose there is a small advantage if you get to put your legs below you ("crumple zone") while still maximizing your cross-sectional area.

Most clothing fabrics are worse at stopping airflow than the tight nylon of a parachute, so the drag will be less than a chute of equal size. If you can somehow get it soaking wet it'll be more effective, as the fibers swell and make it less permeable to air; consequently, you might want to stick your shirt in your jeans before you piss yourself.


That's way beyond insightful, thank you :D Any other ideas on how to get three points? Tying a knot to a belt maybe? I mean we're talking about just a few dozens of second there, right?


(btw, I obviously meant parachute, I was tired while writing that)


Yes you can, but it won't help you much. Modern parachute is not just a shaped peace of fabric - it's a ram-air airfoil of a very complicated shape.


Wow! Glad that I am not the only one that constantly thinks about this when I am on an airplane.


I always opt for the last row.


I have always wondered about this. While this is welcome, I am reading and can feel my blood pressure, stress level, and focus increasing as I read.


I had hard time reading with the formatting of the site even with various "reader" extensions turned on (maybe I'm the only one?). So I looked at the HTML source to figure out why my extensions still couldn't format well... it is 1999 HTML. Tables for paragraphs.

Even copy and pasting to a text editor yields pretty terrible results.

td { padding: 1em; }

Made it somewhat readable for me. Not a criticism but just in case someone has the same problem as me.


I remember reading this in 1999 when it first circulated!


I am very very sorry to break it to you, but this very poorly thought-out and the writer has no understanding of physics or drag. Look around for items after 20000 feet of freefall? There could be a parachute? Sorry are we all in vacuum or something? Do you think they all fall at the same rate? Yes one can survive a fall at terminal speeds but this is just insane to hope there are any items around you after all that fall.


My dear child, 't was in jest. A peculiar one, granted.




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