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I was watching a video where a plane an MD-82 descended 18,000 feet per minute and crashed into a mountain.

The plane was not upside down/on its side/spiraling- it had about a 5 degree pitch up the whole time.

My question is: Would this rapid descent kill you, or at least make you pass out? What is the descent rate that would simply just make you go unconscious?

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    $\begingroup$ It's not the fall that kills you; it's the sudden stop at the end. $\endgroup$ – DeltaLima Sep 2 at 6:20
  • $\begingroup$ If the plane doesn't crash, the descent rate generally can't hurt you. If the plane crashes, the horizontal deceleration is likely to do far more harm than the vertical deceleration. That said, 18,000 feet per minute is pretty fast, like 180 knots, so unpressurized it could cause possibly ear & sinus damage. But those wouldn't kill you. A crash at 180 knots into a flat surface, will - either level flight into a cliff face, or straight down into flat earth or water. $\endgroup$ – Ralph J Sep 2 at 6:27
  • $\begingroup$ I don't trust the accuracy of the described situation. A terminal vertical speed of 180knots in that sort of belly flop orientation doesn't quite pass the sniff test. The question its self is ok though. $\endgroup$ – Max Power Sep 2 at 6:45
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    $\begingroup$ You have heard of skydivers, right? $\endgroup$ – Michael Hall Sep 2 at 15:57
  • $\begingroup$ @Michael Hall: Didn't the guy who jumped from extreme altitude a few years ago actually exceed the speed of sound on the way down? newatlas.com/alan-eustace-world-record-skydive-stratex/34423 (Don't offhand know if the 822 mph/1,323 km/h was greater than the SoS at that altitude, though.) And of course the Apollo astronauts reentered at ~25,000 mph. $\endgroup$ – jamesqf Sep 5 at 18:35
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There is no descent rate that would directly kill you or make you pass out, the notion is nonsense from a physics standpoint. It may be possible to rupture eardrums from the pressure change in some people with pre-existing sinus and ear trouble. It would also be possible to die from the heat of air speeds over mach 2, but the exact speed depends greatly on the aircraft design and is not unique to a descent trajectory.

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I always thought the whole notion of falling from a great height killing you before you hit the ground as complete and utter nonsense. The old wives tale of dieing from a heart attack during the fall is just that, an old wives tale perpetuated by the frequent retelling of it. Minus any pre-existing medical conditions, it is not a sound theory.

Skydiving proves this. After all, skydivers in extreme cases can reach terminal velocities of up to 300 mph.

However, you can lose useful consciousness due to hypoxia above 20,000 feet MSL without supplemental oxygen. The higher you are (and stay), the quicker it will happen.

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    $\begingroup$ +1, but are you really sure an otherwise healthy person can't suffer a heart attack or a similar condition from the extreme psychological stress of the fall and related knowledge of impending death? :-) $\endgroup$ – TooTea Sep 2 at 13:00
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    $\begingroup$ @TooTea They could certainly have one, sure, but the idea that they are dead when they hit the ground is absurd. Unless your heart explodes in your chest (unlikely if you are somewhat healthy), the time it takes for a heart attack to kill you will be more than the time it takes for you to reach the ground. You may be unconscious, but you are probably alive. The more probable theory is that people pass out (faint) rather than have some major medical condition mid-fall. $\endgroup$ – Ron Beyer Sep 2 at 13:52
  • $\begingroup$ @TooTea - I can’t speak for someone who inadvertently finds themselves on the outside of an aircraft in flight or a tall building. As for skydivers, they typically are not of the personality type to suffer from resignation. During a canopy failure, they will spend every second of the rest of their airborne life working to get that chute open. Otherwise, they should not step out of the aircraft. $\endgroup$ – Dean F. Sep 2 at 23:26
  • $\begingroup$ Sure, I meant the passengers of the example MD-82 in question, certainly not skydivers. Given how many people are afraid of flying, I would be surprised if everyone on board stayed calm all the way to the impact. $\endgroup$ – TooTea Sep 3 at 6:56
  • $\begingroup$ @TooTea - You make a valid point. Though, it can be argued that the person’s fear killed them, not the situation. And, certainly not the descent rate. Different people in the same situation, at the same descent rate, will have different reactions and outcomes. Conversely, the same person may have the same or similar reaction regardless of the descent rate. This makes the point not germane to the question about descent rate. It is not quantifiable. $\endgroup$ – Dean F. Sep 3 at 13:36
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You are probably talking about the sensation that is felt when the aircraft starts accelerating downwards.

This cannot be arbitrary excessive and cannot go dangerously high. Most that it could be is the total weightlessness but even that much is not dangerous. Astronauts spend months in this condition.

While the sense of acceleration downwards may feel strong, it is just a sense. The acceleration sensor is in the inner ear. The generic nature of this sensor is the same as the one of sound and light sensor - it does not warn about the dangerous condition of your body, it just reports that it is detecting.

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