Live data from Hacker News

Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

bmj.com

121–130 of 169 posts

Re: Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

#121
Background (2003): A systematic review of the literature found no evidence to support the routine use of parachutes to prevent death from gravitational challenge and concludes with "We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute." [https://www.bmj.com/content/327/7429/1459]

2018: Protagonists of EBM both organized and participated in such a study and found that parachutes don't make any difference in survival when jumping from a plane.

Also in 2018, https://www.cmajopen.ca/content/6/1/E31.full looked at the use of the parachute metaphor in medicine and confirmed most people didn't quite get the joke

Re: Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

#122

> Only two options exist. The first is that we accept that, under exceptional circumstances, common sense might be applied when considering the potential risks and benefits of interventions. The second is that we continue our quest for the holy grail of exclusively evidence based interventions and preclude parachute use outside the context of a properly conducted trial. Both options may be true for different cases. I…

In practice even parachutes are not so simple.

If I'm a passenger in an airliner with no parachute, I definitely don't want my pilot bailing out.

Also, insurance rates on aircraft with airframe parachutes are higher than for aircraft without them - because pilots often panic and pull the chute, which guarantees a hard landing and totals the aircraft, rather than attempting a landing (with, say, a 90% success rate or whatever). The same might apply to individuals: jumping out of a plane is quite dangerous and it might be "statistically" safer to stay onboard and attempt a landing.

Pilots also may take more risks if they have parachutes, known as risk compensation. Like how people drive faster if the car feels safer. https://en.wikipedia.org/wiki/Risk_compensation

Re: Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

#123

Earlier quoted context omitted.

That introduction Haldane quote: > You can drop a mouse down a thousand-yard mine shaft; and, on arriving at the bottom, it gets a slight shock and walks away, provided that the ground is fairly soft. A rat is killed, a man is broken, a horse splashes. "A horse splashes". That's some mental imagery right there.

Makes me wonder if a bunch of the world's smallest flightless mammal (a fraction of the house mouse's mass) were released at altitude, would they survive? (Not proposing that this be done but thought experiments and/or simulations): https://en.m.wikipedia.org/wiki/Etruscan_shrew

This gives "The Taming of the Shrew" an entirely new meaning.

Re: Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

#124

Putting common sense aside. And pretend the height of jump thing is some super abstract and nuanced thing you didn’t spot. Does this result simply mean you just can’t reject the null hypothesis (parachute makes no difference)? Rather than a proof of it?

I think this result actually shows that a parachute doesn't increase death/trauma when exiting a non-moving plane from 2 feet up.

So, worst case for parachute wearers is that they are no worse off than without one. Parachutes are safe for use with regards to de-planing.

Re: Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

#125

Earlier quoted context omitted.

Turkeys can fly, though. Just not the domestic ones :)

And soon Türkiye can even fly F-16s

Türkiye has had those for decades - I remember seeing one take off from Dalaman in the early 00's while I was waiting for a flight there.

Re: Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

#126

I came to leave a snarky joke comment about "in mice?", and then I remembered that mice don't actually need parachutes because their terminal velocity is roughly the same as a human using a parachute [1]. If someone actually ran the study with mice, they'd find that parachutes aren't necessary! 1: https://johnmjennings.com/can-a-mouse-survive-a-fall-from-a-...

The fact that mice don't appear to deliberately jump off high things as a way to get down tells me that they probably do get hurt... Just because they don't fall super fast doesn't mean they don't get injured because they don't have as much distance to "drop and roll" like a human does.

They at least don't seem afraid to take the risk to walk up high vertical walls towards roofs and attics

Re: Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

#128

> Only two options exist. The first is that we accept that, under exceptional circumstances, common sense might be applied when considering the potential risks and benefits of interventions. The second is that we continue our quest for the holy grail of exclusively evidence based interventions and preclude parachute use outside the context of a properly conducted trial. Both options may be true for different cases. I…

In practice even parachutes are not so simple. If I'm a passenger in an airliner with no parachute, I definitely don't want my pilot bailing out. Also, insurance rates on aircraft with airframe parachutes are higher than for aircraft without them - because pilots often panic and pull the chute, which guarantees a hard landing and totals the aircraft, rather than attempting a landing (with, say, a 90% success rate or…

> insurance rates on aircraft with airframe parachutes are higher than for aircraft without them

Are we sure this isn't because aircraft iwth airframe parachutes are wildly expensive and/or heavily-customized vehicles? I'm not sure the correlation has been established as causative here.

Re: Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

#129

I came to leave a snarky joke comment about "in mice?", and then I remembered that mice don't actually need parachutes because their terminal velocity is roughly the same as a human using a parachute [1]. If someone actually ran the study with mice, they'd find that parachutes aren't necessary! 1: https://johnmjennings.com/can-a-mouse-survive-a-fall-from-a-...

From the article:

> Parachute use did not significantly reduce death or major injury

I really recommend reading. It is a very funny thing until you realize you've read a few dozen serious articles, well received by a large community (some times even the academic community) with nearly the same kind of arguments.

Re: Parachute use to prevent death, trauma when jumping from aircraft (2018) [pdf]

#130
post #13
post #12

What point is this article trying to make?

They do a Randomized Controlled Trial on parachutes, but due to ethical reasons the plane is only a few feet off the ground and there's no effect (the parachutes don't have time to deploy).

Are you under the impression there would be an effect on trauma rates if the parachute managed to deploy during a 60cm jump?
Post reply on HN