Hey, there are lots and lots of nasty ways to shuffle off this mortal coil; brutal airline disasters are just one of them. Industrial accidents can be equally nasty, or even worse. Getting trapped in a burning building. Dragged away in a flood. And on and on and on.
As you imbibe, console yourself with the fact that commercial airline accidents, though harrowing, are exceedingly rare. Just as somebody will win the lottery, someone will end up hurt/killed in a plane crash; in either case, it’s just about certain that it won’t be you.
Joe, if a plane nosedives from a high altitude, I don’t think that necessarily means it would go any faster than the 550mph crusing speed. If the engines aren’t working, first of all, the wind resistance alone would be enough to slow it down somewhat. Am I wrong? I know that planes have lost control and hit at 3 or 400mph before - whether they were actual nose dives or some other trajectory, I don’t know. Anyways, it’s all kind of a moot point. Everybody dies regardless.
My next question - forgive my ignorance of physics, but wouldn't the terminal velocity of a plane be the same as a human? I thought all objects fall at the same speed (unless it's a feather, etc.). So, if a plane were 30,000 feet up and lost all engine power and lost control as well, going into a free fall, would the wind resistance not eventually slow it down to about the same velocity as a falling human?
Broomstick mentioned military pilots suffering broken bones upon ejecting from planes. Do we know how fast some of these pilots were traveling? I imagine that the impact of hitting the wind at 1,500mph is rather different than hitting at 4 or 500mph, right? That's not to say they were necessarily going that fast. I'm just asking. Would the commercial jet speed still be enough to do such damage?
Cookingwithgas, your article sounds interesting. Another question though - how do we know that the bodies they found were "ejected" and experienced such a wind stream? Could they not have been enclosed in the fuselage (or some part of it), then detached from it upon impact?
Joe, I happen to like playing the lottery. I enjoy deluding myself with the hope that I might win big and just go spend the rest of my days in Nice. Thanks a lot for bursting my bubble with your logic.
Commercial airliners typically have a thrust-to-weight ratio of around 0.3, give or take. So take a big jet that weighs 300,000 pounds: the engines can sustain a cruise speed of 500-600 MPH in level flight with a thrust of 90,000 pounds.
Now shut the engines off, and instead of level flight, point the plane straight down. Gravity is pulling the plane downwards with about 3.3 times as much force as the engines were pushing it along in level flight. Drag force scales roughly with the square of speed, so in a vertical nose dive, so the terminal velocity (assuming the plane didn’t break up) will be much higher than the normal level-flight cruise speed.
Two other considerations. First, the disparity between cruise speed and terminal dive velocity might be even greater, since they probably don’t use the engines’ absolute max thrust to maintain cruise speed. Second, a vertical dive at those kinds of speeds will rapidly bring you down to more dense air, at which point the terminal velocity becomes much lower.
No.
Terminal velocity is the speed at which aerodynamic drag is equal to the weight of the object. For a fixed composition, drag scales roughly with the square of size, and weight scales roughly with the cube of size: a quarter-inch ball bearing will have a much lower terminal velocity than a cannonball. The drag characteristics of a big commercial airliner in a nose dive are not as immediately clear as those of a solid steel sphere, since an airliner is not a solid metal object that you’ve scaled up from a handheld model. But you can suss it out as I did above, by observing how much force it takes to propel it through the air at a given speed.
Highest aircraft speed with a successful ejection listed here is 800 MPH.
Again, drag force scales roughly with the square of speed. OTOH, it also scales with density, which at 35K feet is about 1/3 that of sea level. So for a human bean with a sea-level TV of ~120 MPH, being exposed to a 500-MPH slipstream at 35K feet, you’d expect about 5 g’s of decel. The problem is that it wouldn’t be uniform: your limbs would be blasted backwards and flopped/fluttered to pieces, and your clothes would be torn to shreds. Much as they’ve observed in the wreckage from this Air France flight.
First of all, the clothes being ripped off suggests exposure to high wind.
Second, as Broomstick has noted, when an aircraft hits the water from a dive, you tend very rarely to find intact bodies. Suffice to say that the remains found in the Challenger (in which the crew module fell as an intact piece with the astronauts strapped in and (at least some) alive for awhile) were described in one article as having been retrieved in five gallon buckets. I don’t want to think too much about what that means exactly, but only two or three of them were identifiable enough to have a funeral (or so I inferred) and “unidentified remains” were buried at the memorial in Arlington Cemetery.
Re: Ejection seats and broken limbs. (IANA military pilot.)
I have an A-7E ejection seat. One design feature is that the sides of it come up in such a way as to help prevent the legs from flailing. IIRC the A-4 Skyhawk uses the same seat, but without the canopy penetrators. The F-14 Tomcat uses Martin-Baker seats. The pilots wear straps around their calves that attach to the seat. In the event of ejection, the straps are pulled in so that the legs don’t flail. As for the arms, I can only guess. I’m guessing that the pilot is expected to hold tightly to the ejection ring, either on the face curtain or between the legs. I’ve heard that F-4 pilots (Martin-Baker seats) often suffered broken limbs.
Someone once told me of an Air Force (possibly ANG) pilot who punched out at high speed somewhere in Alaska. The speed was so great that when he landed he was wearing his parachute harness and his boots, the flight suit being ripped off. I have no idea if this is true, but it makes a good story.
Since it would be impossible to have absolute assurance that sitting is your living room reading a book is completely safe, it seems unlikely that this would be possible for travel at near the speed of sound.
A plane, even unpowered, can certainly exceed cruise speed, and go above it’s rated “never exceed” speed. Bad things can happen, from flight control flutter (as described above by several of our pilot-dopers), to large objects simply being ripped off the aircraft (rudder/vertical stabilizer assemblies, engines, wings, etc.)
Either way, hitting at 400mph, or 550mph is certainly fatal… as is hitting at the 125mph-ish freefall velocity of a human.
In a vacuum, all objects fall at the same speed (no air resistance).
Terminal velocity in air is different for each object. It’s a balance between weight, “streamline-ness”, and surface area. At some point, the force of the air moving out of the way balances out the acceleration due to gravity, so the object stops accelerating downwards and begins to move at a constant velocity. A human in “standard freefall postion” falls slower than one falling head or feet first. In the former, the surface area is their full frontal profile. In the latter, it’s just the “top down, or bottom up” surface area.
A plane “feathering down” would fall slower than one pointed nose down.
I am sure I read this somwhere, but can’t recall the source, but it said that of the bodies found, there were some( I don’t remember how many) where they couldn’t determine the sex of the individual.
Well short of a blood test they probably can’t. They probably used the word bodies because it sounds more humane. They actually probably found random limbs and things like that.
Yes, actually it will. Airliners are capable of breaking Mach 1 - they don’t usually because the engines are powerful enough to push them that fast, but the airframe can certainly be accelerated to those speeds given sufficient motive force. Gravity can supply sufficient force.
Yes.
Now, an airplane pancaking - that is, falling with the fuselage/wings parallel to the ground - will encounter sufficient air resistance to fall slower than an airplane in a nosedive, but either is going to hit very hard.
Correct.
Barring some very small, very light aircraft where it is, at least theoretically, possible to survive such a thing, particularly if it occurs low enough that the airplane simply doesn’t build up a lot of speed. Passengers jets, however, are so big, massive, and fast that it would be pointless to consider it as a possibility.
Only in a vacuum.
Um, sure, there’s a difference - either one could be fatal, but the faster speed is more certainly fatal.
Yes.
This is also a major obstacle to the idea of parachuting out of an airliner (assuming you get past the problem of getting a pressurized fuselage open).
The clothes being ripped off is sort of a clue there. Whether or not they’re found still strapped into their seat might also be a clue. It’s possible some people were in some fragment of the fuselage but on impact there could be characteristic patterns of damage that would be a clue.
Just because the body is mostly intact does not mean it is entirely intact. There could still be massive, massive damage and, um, appendages could be damaged or torn off. Bodies retaining some clothing but severely damaged may not be identifiable until unclothed in the morgue (there not being much difference between male and female blue jeans in some cases, for instance). Also… trying to be delicate again… the bodies were floating days in tropical waters, and between normal decay, warm temperatures, and nature’s little scavengers… well, again, soft fleshy bits may not be present, or if they are present they may be distorted by damage, bloating, etc.
That would be indicative of an intact airplane impacting - if they were ejected at altitude and fell the bodies wouldn’t likely exceed the usual 125 mph terminal velocity of a human body. Such an impact will cause massive trauma and, um, some small parts may detach (teeth, for example, may be shattered if the body hits face first) but human skin and muscle tissue is strong enough to hold the broken bits together in a recognizably human shape at those impact speeds. From the sound of it, they’re pulling actual bodies with limbs still attached out of the water. It’s just that the long bones in the limbs are in many pieces.
LSLGUY, If you dont mind my question, what type of planes do you fly? It’s just i have an amazing respect for anyone who can control such a massive device.
Without wishing to diminish the respect due LSL Guy by so much as a jot or tittle, I’ll note that an enormous amount of (mostly successful) design effort goes into making those massive devices easily controllable.
Sorry. Death is like that, and the death of hundreds even more so. I’m trying to tread between truth-and-honesty and not-causing-anyone-to-upchuck.
However, people have survived riding the wreckage of an airplane to the ground so it’s not invariably fatal. It’s just like someone else said - it’s almost certain that someone other than you will win the lottery.
No, you wouldn’t. I wouldn’t. It’s… ewwwwwww on a whole new level.
Mangeorge, it’s gruesome stuff indeed. It makes you wonder how people like us can continue a “discussion” about it for so long. Now, continuing with my morbid curiosity, how much can be determined by the medical examiners? Can they tell for sure whether someone was in the fuselage and then was detached from it as opposed to falling through the air on their own? You said that if their clothes are all gone, that’s a good sign, which makes sense. But would the injuries be different? Obviously they would probably not be recognizable if they were in a fuselage traveling at 400mph or something, but what if it was just some piece of fuselage falling at around 150 or 200mph, for example. Could they still be intact like a person hitting the water? Would the difference in injuries to the body be obvious? I know it makes no difference whatsoever - I just have this strange fixation on the whole subject.
Another question - if someone is sucked out of the plane, could they be sucked into one of the engines? Yeah, I know I'm not helping to lower the gore factor much. I assume they'd have to be in front of the engine, so seated somewhere well in front of the wing. Is that right?
back in '89, United Airlines flight 811 lost a good chunk of roof from its forward fuselage. Several passengers and a flight attendant were ejected from the cabin during the decompresson, and IIRC there was evidence that one of them had been sucked into an engine.
Yea. It’s really bloody irritating when people with direct, first-hand, professional knowledge come in and answer your question in immense detail. I don’t know how you find the strength to go on.
And hence my question about not being able to determine the sex of the individual.
I can’t imagine a situation where I have a body, no matter how badly damaged, and I can’t determine whether it is male of female. Probably the only times I wouldn’t be able to do that is if the body is presented is
badly decomposed resulting in most of it being eaten away,
where the relevant parts are burnt away and missing altogether
Wisernow, I don’t know but I think the people could have sustained massive injuries while in or exiting the fuselage. Then add the fact that they’ve been floating around in the sea for a week or two. So, while most of the body may be intact, perhaps it’s not entirely intact. Maybe someone is missing 1/2 of their hip and “parts” and the torso is too badly decomposed to tell the gender, for example - gruesome stuff like that. Or, as someone else pointed out, they may have found some limbs here and there, although from what I’m hearing, it sounds unlikely that they would be dismembered as a result of a free fall and impact with the water - it sounds like that would be more indicative of an impact at hundreds of mph inside a fuselage.
Here's another question. They say that the plane was out of radar contact at a certain point during the flight, which is apparently normal over the ocean. But wouldn't other planes over the ocean in that general area have the Air France flight on their radar? Is it possible that another plane could have seen the flight on the radar and seen the moment when it disappeared, thus pinpointing the location where it broke up? Obviously that didn't happen in this case, or someone would have said so - but is that even possible? I guess the other problem is that even if you could see exactly where it left the radar, it could have just been damaged and traveled another 50 or 100 miles during its descent and break up. I don't know...
