3 ms·

Shower thought: after some inflection point, does your likelihood of survival actually increase with altitude? With the additional height you gain additional ti

by yomly 7y ago

Shower thought: after some inflection point, does your likelihood of survival actually increase with altitude? With the additional height you gain additional time to plan and travel to fall more optimally, while your acceleration should fall to nearly zero. Of course, there may well be a secondary ceiling (pun) where air pressure and O2 create new complications...

kibwen 7y ago
There's some evidence that this is true for cats at least, where falls above a certain height begin to cause fewer injuries, presumably due to giving the cat time to twist their body around into a legs-down parachute-like shape. http://www.todayifoundout.com/index.php/2010/11/domestic-cats-can-fall-from-any-height-with-a-remarkable-survival-rate/ http://www.todayifoundout.com/index.php/2010/11/domestic-cat...
daveoflynn 7y ago
> after some inflection point, does your likelihood of survival actually increase with altitude? For humans, no. After ~10sec you’re falling at terminal velocity, which is generally 2-300km/h, and your odds of survival are extraordinarily close to zero. This lady had a double malfunction, where there were issues with both main and reserve parachutes, but per a police report (1), she was descending at 60km/h, so she must have had at least some parachute material out and slowing her fall. She’s very lucky, despite what’s likely to be a shitty next couple of years of rehab, but this isn’t a “fell from an airplane without a parachute and survived” miracle. (1) https://www.lenouvelliste.ca/actualites/une-parachutiste-gravement-blessee-apres-une-chute-144ab252158928367b84d336c0ebe5c2 https://www.lenouvelliste.ca/actualites/une-parachutiste-gra...
- Insanity 7y ago
  I wonder if psychologically this ended up being a good thing. As in, physically the rehab might be bad but mentally.. it's bound to put things into perspective.
- 725686 7y ago
  "For humans, no. After ~10sec you’re falling at terminal velocity" That means that falling higher will not increase your already slim chances of survival, and might well increase them, if ever so slightly. No?
  - daveoflynn 7y ago
    Hard to say definitively - double malfunctions are relatively rare, so the sample size isn’t enormous. More time can increase the likelihood that you can get some piece of parachute fabric above your head. And if you can do that, the odds go way up. There’s a saying I was taught on the first jump: “keep fighting until your goggles fill with blood.” But if you cannot get a parachute out for some reason, a longer freefall will only give you more time to contemplate your fate.
- yomly 7y ago
  Right so 300kmph = 83.3 m/s which means every 83.3 metres (call it 100) buys you an additional second of thinking time and back of the envelope calculation (2km/minute) [0] suggests you can move up to 33 metres per second horizontally (feel like this is optimistic - I openly welcome corrections here...) In any case a fun thought experiment [0]https://www.quora.com/What-is-the-average-horizontal-distance-that-skydivers-travel-from-the-planes-door-to-their-landing-site/answer/Dave-Sparazynski https://www.quora.com/What-is-the-average-horizontal-distanc...
  - daveoflynn 7y ago
    There’s a joke in skydiving: “What happens if your backup parachute fails? You aim for the car of the person who packed it”
Balgair 7y ago
It took a long time for aircraft pilots to discover that height is actually good with airplanes. After a few seconds, you are at terminal velocity. This ends up being only a few hundred meters. After that, you have a few thousand meters before the air gets too thin to breathe. So, the higher up you went, the more time you would have to react to issues that arise. Largely, you can measure the height of the airplane in mistakes. It takes time to fix a mistake. You have to first realise you are in a mistake, then you have to take in information, then you have to decide what to do, then you have to do it (the OODA loop). Since you reach terminal velocity rather quickly, it's all about the time you have left before you reach the ground and die. So in airplanes, the higher you are, paradoxically, the safer you are.

by yomly 7y ago

kibwen 7y ago

There's some evidence that this is true for cats at least, where falls above a certain height begin to cause fewer injuries, presumably due to giving the cat time to twist their body around into a legs-down parachute-like shape. http://www.todayifoundout.com/index.php/2010/11/domestic-cats-can-fall-from-any-height-with-a-remarkable-survival-rate/ http://www.todayifoundout.com/index.php/2010/11/domestic-cat...

daveoflynn 7y ago

> after some inflection point, does your likelihood of survival actually increase with altitude? For humans, no. After ~10sec you’re falling at terminal velocity, which is generally 2-300km/h, and your odds of survival are extraordinarily close to zero. This lady had a double malfunction, where there were issues with both main and reserve parachutes, but per a police report (1), she was descending at 60km/h, so she must have had at least some parachute material out and slowing her fall. She’s very lucky, despite what’s likely to be a shitty next couple of years of rehab, but this isn’t a “fell from an airplane without a parachute and survived” miracle. (1) https://www.lenouvelliste.ca/actualites/une-parachutiste-gravement-blessee-apres-une-chute-144ab252158928367b84d336c0ebe5c2 https://www.lenouvelliste.ca/actualites/une-parachutiste-gra...

Insanity 7y ago
I wonder if psychologically this ended up being a good thing. As in, physically the rehab might be bad but mentally.. it's bound to put things into perspective.
725686 7y ago
"For humans, no. After ~10sec you’re falling at terminal velocity" That means that falling higher will not increase your already slim chances of survival, and might well increase them, if ever so slightly. No?
- daveoflynn 7y ago
  Hard to say definitively - double malfunctions are relatively rare, so the sample size isn’t enormous. More time can increase the likelihood that you can get some piece of parachute fabric above your head. And if you can do that, the odds go way up. There’s a saying I was taught on the first jump: “keep fighting until your goggles fill with blood.” But if you cannot get a parachute out for some reason, a longer freefall will only give you more time to contemplate your fate.
yomly 7y ago
Right so 300kmph = 83.3 m/s which means every 83.3 metres (call it 100) buys you an additional second of thinking time and back of the envelope calculation (2km/minute) [0] suggests you can move up to 33 metres per second horizontally (feel like this is optimistic - I openly welcome corrections here...) In any case a fun thought experiment [0]https://www.quora.com/What-is-the-average-horizontal-distance-that-skydivers-travel-from-the-planes-door-to-their-landing-site/answer/Dave-Sparazynski https://www.quora.com/What-is-the-average-horizontal-distanc...
- daveoflynn 7y ago
  There’s a joke in skydiving: “What happens if your backup parachute fails? You aim for the car of the person who packed it”

Balgair 7y ago

It took a long time for aircraft pilots to discover that height is actually good with airplanes. After a few seconds, you are at terminal velocity. This ends up being only a few hundred meters. After that, you have a few thousand meters before the air gets too thin to breathe. So, the higher up you went, the more time you would have to react to issues that arise. Largely, you can measure the height of the airplane in mistakes. It takes time to fix a mistake. You have to first realise you are in a mistake, then you have to take in information, then you have to decide what to do, then you have to do it (the OODA loop). Since you reach terminal velocity rather quickly, it's all about the time you have left before you reach the ground and die. So in airplanes, the higher you are, paradoxically, the safer you are.