I may not be adding anything new to what has been written, but this is what I’ve learned by reading a few things over the past week (because I had the same morbid curiosity.) First of all, it depends on the altitude. If you were 35,000 feet up, like the Air France flight, you have about 20 seconds until you pass out. But there are a number of factors. Was the person thrown out of the plane or not? Was the oxygen mask used? Were they at that altitude for long or did they suddenly plummet? As has been pointed out already, the time of consciousness depends on your altitude. At 30,000 feet it is about 30 seconds, a few thousand feet less and it’s 1 minute, etc. So, let’s say that someone is instantly thrown out of the plane by some violent breakage of a piece of the plane. They could either be in their seat or not. First of all, at that altitude the air would be around - 30 or - 40 degrees. Also bear in mind that they may have been traveling between 300 - 600mph. I imagine that the force of the wind and/or the shock of suddenly flying through the air at hundreds of miles per hour in such cold could knock someone out. Who knows - maybe it could even break a neck. This is all assuming that they’re not unconscious or dead already from being hurled against something (or having an object hit them) or being in a depressurized cabin at that altitude for several minutes. It’s possible that the turbulence could have been so great that they couldn’t even grab the mask or perhaps were too freaked out to think about it. In that case, they would quickly pass out if they remained at that altitude. It sounds like whatever happened was fairly quick - I don’t think they were struggling for 1/2 an hour at that altitude or anything - just speculation. So, I doubt anyone died from the lack of oxygen (unless they were elderly or had other medical conditions), but many may have passed out. As they descended to a lower altitude, it’s possible that some may have woken up (at least to a 1/2 awake state) around 10,000 feet or so. As for the person who gets thrown out of the plane, if he’s not unconscious or dead already, 20 seconds or so wouldn’t quite be long enough to get into an altitude with sufficient oxygen (if they’re at 35,000), so I think they would pass out. Whether they would awake again is anyone’s guess. If you’re at 30,000 feet, however, it’s possible that you may be conscious the whole time, because you’d have more like 30 seconds, which would be plenty of time for you to fall into the 1 minute range, then 2 minutes, etc. Anyone unlucky enough to be alive and awake throughout would then have at least about a 120mph impact with the water (the speed of fall can vary depending on shape, size, and your position as you fall, which affects the wind resistance) which is basically like hitting the ground. Anyone still alive in the fuselage would almost certainly die upon impact. Even if it were just falling through the air and not hurtling straight down with engines thrusting, the impact would still be tremendous. Depending on the scenario, the plane probably could have hit anywhere between that terminal velocity (basically just a free fall) and 5 or 600mph if it was still being “flown” in some way. I do think that many people could possibly pass out from the terror of it all, if nothing else. I’m no expert, but this is what I’ve deduced…
Bear in mind that the question of when they would pass out, etc, is all assuming that the cabin was depressurized at 30 - 35,000 feet. I don’t actually know when that happened. The plane could have just plummeted and had pieces break apart on the way down. They may not have even been at a high enough altitude for a long enough time for people to lose consciousness. Of course, I imagine that getting tossed about in a tumbling plane at hundreds of miles an hour could just as easily knock someone out, even if belted in. There are any number of ways - a passenger with a window seat could knock their head against the wall, someone could have their head thrown into the seat in front of them, etc. Just whipping around and tumbling upside down would probably be so disorienting that one might be in a daze or pass out, even if the head didn’t actually hit anything.
I actually used to joke to my friends that I was going to start wearing a parachute whenever I traveled by air. Of course, I'd have to find a way to get out of the plane if I weren't ejected already. I'm not sure that landing in the middle of the ocean in a storm with little hope of being rescued in time would be a much better option. I'd have to weigh my options during my descent through the chilly air with chute strapped on. Would my fear of sharks and drowning outweigh my fear of a grisly impact with the water? Land would make the choice easier. Then again, it would depend on the flight route. What if I ended up in West Virginia in some village of mongoloid banjo players? I'd have to really think it through before pulling that cord.It’s not the banjo players you have to worry about in Appalachia…
An interesting data point I’d not yet seen, from the Times Of London:
The best you could hope for in a freefall is the terminal velocity of a human body which is about 125 mph. If the plane remained intact it would probably hit at a faster speed.
Huerta88, what exactly do they mean by “died in the shock of break-up and depressurization”? I mean, what is the actual cause of death? Losing pressure could knock someone unconscious, but if they were only at that altitude for a short time, it wouldn’t necessarily kill them, right? I’m not sure what “shock of the break-up” means either. I mean, being thrown around the plane and dying from head trauma is one thing, but what if that didn’t happen?
I have another question. Why would they assume that if no one drowned, the plane must have broken up in flight? Yes, it seems pretty obvious in the Air France case that it did break up in flight. But let's say a plane hits the water intact. If it's a nosedive, it could be traveling anywhere between 150 and 5 or 600mph, depending on what the engines were doing. I would assume everyone would die instantly. Perhaps I'm wrong about that...Well, I don’t know what they meant. There has been a lot of debate upthread about how quick death would be.
I think they would die instantly, from the g-forces.
If a large commercial aircraft were to hit the water intact, then its trajectory could not have been anything close to a nosedive. On 9/11, the engines alone (with a thrust-to-weight ratio of about 0.3) were enough to power United 175 up to about 550+ MPH in level flight. In a nose dive, regardless of what the engines are doing, gravity is pulling the plane down with a “thrust”-to-weight ratio of 1; the plane will exceed safe speed in short order and get torn to pieces.
As was discussed in a thread elsewhere on surviving a freefall from altitude, high-speed impacts with water are extremely injurious and often fatal. A human body in freefall (~120 MPH) will experience accelerations of several hundred g’s upon impact. If a fuselage were somehow able to survive a 600+ MPH freefall down to the surface of the water, it would be shattered on impact - and so would its occupants.
I for one would pay extra for the absolute assurance that flying was completely safe. How hard would it be to install a chute on planes for the rare chance of something like this happening?
another thing that I’m concerned about are seatbelts. Would it be so much harder to install shoulder harness plus lap seatbelts, than just a lap belt. Those lap belts would probably do alot of damage in an accident while the shoulder harness belts would distribute the force across more area of the body.
The latest news says this:
So if it broke up high up, bodies would have multiple fractures, but if it crashed into the water intact, bodies would be severely fragmented? Someone explain to me the critical difference between multiple fractures and severe fragmentation. Is the difference one of intact bodies but internal injuries as compared to separated body parts?
That would be my guess. The plane crashing into the water would mean the bodies would be crushed within the wreckage and probably sliced into pieces. If the bodies free-fell apart from the plane, they would either suffocate on the way down (seems unlikely to me), or more likely die of multiple traumas when their bodies hit the water. Pretty much exactly like a parachutist who forgets to strap on a chute.
Also, the terminal velocity of an intact plane, or at least fuselage if bits had been ripped off, would be a lot higher than that of a human body.
Yeah, but how do you get absolute assurance that your parachute is absolutely safe?
More to the point: you’re seeking to reduce already-infinitesimal odds of personal disaster by a measurable amount. That’s pretty hard to do. The flying portion of your journey is already the safest part of it - by a long shot. If you want to increase your odds of surviving the whole trip, you should try to drive more carefully to and from the airport; that’ll give you far more benefit (at far less cost) than a parachute.
Yes.
Whereas car seat shoulder belts have solid anchor points on the door pillar, there’s no equivalent anchor point for the middle seats and aisle seats on an airplane. Airliner seats are lightweight things - not designed to bear restraint loads - so you couldn’t anchor the shoulder belt to the seat back without significant reinforcement. All of this adds cost to the base price of the aircraft; adds to maintenance cost; and the increased aircraft weight will add to the fuel/operating cost. Your ticket price will increase noticeably.
I’m not sure shoulder belts on an airplane would improve the safety situation much either. Whereas car crashes often involve a frontal impact, aircraft turbulence is more side-to-side and up-and-down, neither of which is helped by a shoulder belt. And unlike a car crash, in a commercial airliner crash you’ve generally got lots of warning about an impending impact, giving you time to get into the standard “brace” position to cope with any serious frontal impact, e.g. from a less-than-gentle crash-landing.
One cheap partial solution would be to have all the seats face backward so they can absorb any frontal movement. Pretty incremental gains I’d expect.
Thanks LSLGuy, I will never fly again…
I’m not Huerta88 but I’ll take a stab at this one. Consider that a force that can rip apart an airplane can exert considerable force on a human body. Military pilots ejecting at high speed from aircraft often experience limb fractures, even multiple fractures in the long bones of the arms and legs. It’s because air is an actual physical thing, and if you eject from an aircraft going at a speed greater than the terminal velocity of a human body that air is going exert force on your body as you abruptly slow down. If you’re a lot above terminal velocity it’s going to be a lot of force. Terminal velocity of a human being is about 125 mph (there are ways to go faster, but it requires practice and experience in free fall and is generally seen only in dedicated skydivers). Air France may have been going 2-3 times faster, or even more than that. If the fuselage is breached you’re going to be slapped by that greater-than-terminal-velocity airstream and it’s going to be like hitting a solid object. It can break bones. It can also literally tear the clothes off your body - and apparently many of the bodies found are in a state of undress.
Of course, even multiple leg and arms fractures are necessarially fatal, but shattered bone fragments can sever large blood vessels. Shock could set in quickly, and the cold, thin air won’t help.
If the airplane hits the water at several hundred miles per hour you won’t have bodies, you’ll have body parts. The forces involved in an intact airliner impacting either ground or water breaks everything into itty bitty pieces.
These determinations are based upon fragmentation of the airplane, condition of the bodies, and various other factors. So, for example, body parts might be from either an in-flight breakup or an explosion - the presence or absence of shrapnel in the bodies may be what shows what happened. In flight breakups at altitude typically mean that the bodies hit at human terminal velocity, which generally kills you but doesn’t tear your body apart. Break ups on impact fragments everything, including people. This is based on past aircraft accidents, of which we have nearly a century of documentation and experience.
We discussed this at length in several past threads, to which I refer you:
Airliners and parachutes:
Mostly small planes:
I don’t think the engineering problem is insolvable, it just wouldn’t be cost-effective. I realize, of course, that many people say “WHAT?! My life is PRICELESS!”. I understand the sentiment, but let’s face it, the universe is a dangerous place and big corporations don’t see you as priceless, more like a million or two, maybe more if the jury award is higher.
It’s also akin to the question of Why don’t we make the airplane out of the stuff the black boxes are made of? which Cecil kindly answered for us back in 1996. The short answer is the classic “The interstates aren’t wide enough”. At a certainly point adding more safety equipment impacts performance, either making long distance flight impractical or impossible, or too expensive.
Then why are they pretty standard equipment on smaller airplanes? On one occasion an open cockpit airplane I flew not only had a seat harness that strapped me to the seat, it had a second one that strapped me to the fuselage, too, “just in case”. (As I was flying with someone with a fondness for inverted flight that wasn’t as much overkill as you might first suppose…). Or, more specifically, ever see the restraint harnesses the flight attendants use? Notice they often sit facing the rear? I assure you the folks up front in the cockpit have at least a four point harness. More strapping does help, that’s why the flight crew has it.
So why don’t the passengers get all those straps? Well, aside from the engineering problem (again, awkward but not impossible to solve) the customers don’t like seatbelts and they don’t like to sit facing backward. It’s not rational but it is how people are. A few airliners have tried it and then discontinued it. The military will make its people sit backward, but then, they also dictate hairstyle, how often they bathe, what they eat, what they wear, and the military doesn’t feel compelled to offer windows, choice of seat, inflight meals or snacks, blankets, pillows, or inflight movies or reading material, either. It’s sit down and shut up soldier, be glad we didn’t duct tape you to the outside of the fuselage.
Actually… no, I’m not sure you get “lots” of warning. Usually, if there’s “lots” of warning the pilots - who, after all, will be first at the impact point and will have an entire airliner fall on top of them microseconds later and may want to avoid that sort of ouch - will do just about anything allowed by physics to avoid said impact or reduce the force of it. However, hitting birds, terrain obscured by clouds, etc. generally doesn’t give you a warning. With a breakup due to weather you may get “warning” in the form of severe turbulence but it’s not going to help you.
Yes - “severe fractures” means the body parts are still connected, even if they bend in funny places that they shouldn’t bend. Severely fragmented means… parts. It can mean very, very small parts. I’d get more explicit but I don’t want to be too gross. Let’s just say that it is possible to reduce a human body to something like burned chicken nuggets, with a few slightly larger pieces mixed in. Or worse.
I think we’re saying the same thing, i.e. it’s not really cost effective. Also, FWIW, this sort of thing typically isn’t even a corporate decision; there are any number of safety measures the airliners wouldn’t have implemented except because of FAA mandate. I vaguely recall hearing years ago that for decision-making purposes, the FAA valued a human life at one million dollars; if a safety measure would cost the airlines X million dollars and was expected to save Y lives, then as long as Y >= X, it was a good deal and the safety measure would get implemented. No doubt there’s more to the decision than that (how do you value injuries?), and the arbitary value may be something other than $1M these days, but you get the idea.
Are they on all seats in a small plane, or just the pilot/copilot seat?
The FA seats I’ve seen are rather quite a bit different from the typical passenger seat. For one thing, when they’re facing the rear, it’s because their back is to a bulkhead; it’s just that it happens to be a convenient place to put a tiny short-term seat for the FA, something you wouldn’t make a passenger sit on for a 12-hour flight.
I’m not arguing that it wouldn’t help at all; indeed, a mandatory multi-point harness, crash helmet and HANS device for all occupants of an aircraft would probably eliminate turbulence-related injuries and greatly increase crash survival rate. I suspect though that the cockpit crews’ restraint system has two purposes, with survival being secondary: I think perhaps the primary reason they are securely strapped in so that they can maintain control of the aircraft when the going gets rough. When the heavy turbulence hits, it’s gonna be hard to hit that one switch on the instrument panel (or apply appropriate inputs to the control yoke) if your torso is flopping back and forth; better to strap in snugly so you have a solid platform from which to reach with your arms.
It does depend somewhat on the airplane. Some of the older ones are problematic for installing shoulder belts due to lack of a good place to anchor them, but wherever possible retrofits have been developed even for the oldest models still flying (which can be greater than 60 or 70 years these days). Certainly all new designs have shoulder as well as lap belts, and four-point harnesses are quite common these days even in non-aerobatic aircraft.
Keep in mind that on some of the airplanes I fly there are only two seats anyway - the copilot seat and the passenger seat are the same thing. Seats behind the pilot and copilot are less likely to have shoulder harnesses but they are not unknown and becoming more common.
Interestingly enough, airbags have also been developed for aircraft - but they aren’t in the “steering wheel”, they’re incorporated into the belts, usually a shoulder belt. I would expect that this system could be adapted for use in airliners but, again, there is weight and expense. It would almost certainly prevent or reduce injuries from a passenger hitting a seatback in front of him or her in the event of a sudden stop, although clearly not all such accidents are survivable regardless of safety equipment.
But their rear-facing seats are safer in many situations, and you want the FA’s to survive because they’re the ones who are trained to get passengers out of an airplane in an emergency. If there was an advantage to a forward-facing seat the FA’s would have those. The FA’s also usually have more than just a lap belt, too, and again that’s for safety while their in their seats, although, of course, a good part of the flight they’re up and about.
If the turbulence is bad enough reaching a switch can be frustrating even if your torso is secured. Just because your torso is stationary relative to the airframe doesn’t mean your arms can’t flop around. Yes, strapping in does keep you in your seat during turbulence, but the airlines would like their flight crews to survive accidents, if for no other reason than it is cheaper to replace passengers than crew, in which the airline does have some time, training, and money invested.
An AP story that ran in the Washington Post today said that autopsies shows extensive broken bones in the recovered bodies, suggesting that the aircraft broke up in the air. The Post article quoted Jack Casey, an aviation safety consultant in Washington, as saying “Getting ejected into that kind of wind stream is like hitting a brick wall–even if they stay in their seats, it is a crushing effect. Most of them were long dead before they hit the water, would be my guess.” It does not appear that Casey is part of the investigation but was commenting based on the reports of the autopsies. Casey is not quoted in other versions of the AP article I found.
This thread has created a strong desire for a large glass of hard liquor. Just the thought of some of these scenarios makes me cringe.