6 ms·

Every time I read about these plane accidents, I wonder why planes don't have any emergency features to save these people. Couldn't you build a plane that would

by vfinn 8y ago

Every time I read about these plane accidents, I wonder why planes don't have any emergency features to save these people. Couldn't you build a plane that would eject the cabin as a parachute module or something. Yes, I'm sure this is naive, but why? Edit: My point is that almost anything is better than crashing down with the plane.

jfk13 8y ago
Can you imagine the scale of parachute that would be needed to safely bring an airliner cabin to earth? Could a parachute on that scale actually be made sufficiently strong (and light), and successfully deployed? I doubt it.
- ajuc 8y ago
  Yes. It would be expansive though.
- agumonkey 8y ago
  I want a wingsuit on my ticket. If I die at least I'll be superman-like for 30minutes
- saiya-jin 8y ago
  Imagine 500m wide parachute. Would probably weight few tonnes, be very complex to deploy (say only above 1-2km altitude), very hard to inspect regularly etc. The other problem is, a lot of death/damage is done after plane hits the ground and starts to burn. You wouldn't be able to prevent that, since emergency parachute falls are hard ones. So you might still end up killing everybody on plane.
agumonkey 8y ago
costs and motivation I suppose some air vehicles have whole frame parachutes but not the scale of 737. I was wondering if a plane could not be made out of separate cabins coupled together (I can hear engineers die of laughter) so that they could be break loose with their own parachute.
- vfinn 8y ago
  Yes, that splitting up would be one of the follow-up questions.
jakecopp 8y ago
Hard engineering problem - where do you open up the fuselage to get the people out? It's a tube so you can't weaken it. You also can't open a hole at the back and let them slide out backwards, you'd need a cylindrical tube in a tube which can then slide out. That's a HUGE amount of extra weight and complexity. Planes are so so much safer than cars. Before we parachute people out of passenger planes we should be ejecting people out of the roofs of cars if an imminent collision is detected :)
- fulafel 8y ago
  Maybe just jettison wings+engines+cargo? Though I agree that broadly safety is solved. And obviously we must heavily reduce air travel to combat global warming.
  - TheSpiceIsLife 8y ago
    The question then becomes are can a plane fly with each of those attached by structural bulkheads & explosive bolts. The remaining ‘crew and passenger capsule’ would need to remain sealed.
    - fulafel 8y ago
      Maybe solid forms could be explosively or electrically welded off.
      - TheOtherHobbes 8y ago
        No. This speculation is just pointless. It's simply not a solution given the engineering practicalities and cost constraints. It's also not a good way to solve what is essentially a software problem. Well-designed planes are ridiculously safe compared to almost any other mode of transport. And it's completely possible to design planes that handle all but the most extreme and unlikely edge cases. The problem here isn't that passengers didn't have a Rube-Goldberg escape route, but that Boeing made some serious design errors - and then apparently tried to cover them up.
russdill 8y ago
Go look up some of the recent airliner incidents. It doesn't appear that parachutes would have helped very many, if any. To make matters worse, such a feature would greatly cut down on passenger numbers per plane, which means more flights, which means more accidents. https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_commercial_aircraft https://en.wikipedia.org/wiki/List_of_accidents_and_incident...
- vfinn 8y ago
  True. Quite many incidents / accidents during the takeoff. Also, crashes into mountains seem common as well. Not sure what the reaction time is in those cases.
amelius 8y ago
Halfbaked idea: perhaps you could make an airbag that you can wear as a garment, and which you inflate if a crash is imminent. Of course, if everybody in the plane wears one, you could have a space problem, but it would provide extra protection by compartmentalization.
tialaramex 8y ago
The mass involved is far too great to be practical for parachute descent. Also, when are you going to "eject" this parachute module? Most serious accidents happen in the phases of flight very close to the ground, take off and landing. But just deploying a parachute won't work when you're so close to the ground. Try it for yourself if you like, buy a parachute, attach it, and jump off a ten story building. Your corpse will be surrounded by as-yet undeployed parachute fabric at the bottom. A fighter jet gets around the being too close to the ground problem by adding a rocket motor. When you "eject" the rocket shoots the pilot's entire seat into the sky first. If you want to eject the entire cabin you're going to need a very big rocket. Not crashing the plane is better. The goal is to not crash the plane whereupon this is all irrelevant. If you're wondering why that wasn't enough for fighter jets the answer is that the other guy's fighter jet is trying to shoot yours out of the sky. Planes don't fly once you put enough bullets into them. How many is "enough"? Well it may be prudent to eject before getting a firm answer. Small prop planes can fit parachutes that try to save the whole fuselage, these have been seen to work at least sometimes, but they're very much a last ditch, they are expensive and they're only "practical" (if that's even the right word for something so expensive and relatively ineffective) for small planes.
marsRoverDev 8y ago
Because said system would be very heavy, and probably on balance it would result in more crashes due to an increased number of failure modes.
DuskStar 8y ago
I think zero-zero ejection seats are a good point of comparison here. These are the state-of-the-art ejection seats used by US fighters and bombers, designed to function from a dead stop on a runway. That's what you'd need for this to be useful in the flight regime most accidents occur in. Unfortunately, ejection seats suck to use. Like, mild chance of killing you, very high chance of breaking bones, almost certain to make you a few inches shorter from compressing your spine levels of suck. This is assuming that you don't hit anything on the way out, of course - and don't land in the fireball. And that's with trained, fit pilots who are expecting the ejection. Can you imagine what happens to Grandma who's started to lose bone density? Or the baby on their mother's lap? And that's before you start considering the issues with having that many parachutes and rockets in close proximity, or the weight. So that's why planes don't have features to save these people.

by vfinn 8y ago

jfk13 8y ago

Can you imagine the scale of parachute that would be needed to safely bring an airliner cabin to earth? Could a parachute on that scale actually be made sufficiently strong (and light), and successfully deployed? I doubt it.

ajuc 8y ago
Yes. It would be expansive though.
agumonkey 8y ago
I want a wingsuit on my ticket. If I die at least I'll be superman-like for 30minutes
saiya-jin 8y ago
Imagine 500m wide parachute. Would probably weight few tonnes, be very complex to deploy (say only above 1-2km altitude), very hard to inspect regularly etc. The other problem is, a lot of death/damage is done after plane hits the ground and starts to burn. You wouldn't be able to prevent that, since emergency parachute falls are hard ones. So you might still end up killing everybody on plane.

agumonkey 8y ago

costs and motivation I suppose some air vehicles have whole frame parachutes but not the scale of 737. I was wondering if a plane could not be made out of separate cabins coupled together (I can hear engineers die of laughter) so that they could be break loose with their own parachute.

vfinn 8y ago
Yes, that splitting up would be one of the follow-up questions.

jakecopp 8y ago

Hard engineering problem - where do you open up the fuselage to get the people out? It's a tube so you can't weaken it. You also can't open a hole at the back and let them slide out backwards, you'd need a cylindrical tube in a tube which can then slide out. That's a HUGE amount of extra weight and complexity. Planes are so so much safer than cars. Before we parachute people out of passenger planes we should be ejecting people out of the roofs of cars if an imminent collision is detected :)

fulafel 8y ago
Maybe just jettison wings+engines+cargo? Though I agree that broadly safety is solved. And obviously we must heavily reduce air travel to combat global warming.
- TheSpiceIsLife 8y ago
  The question then becomes are can a plane fly with each of those attached by structural bulkheads & explosive bolts. The remaining ‘crew and passenger capsule’ would need to remain sealed.
  - fulafel 8y ago
    Maybe solid forms could be explosively or electrically welded off.
    - TheOtherHobbes 8y ago
      No. This speculation is just pointless. It's simply not a solution given the engineering practicalities and cost constraints. It's also not a good way to solve what is essentially a software problem. Well-designed planes are ridiculously safe compared to almost any other mode of transport. And it's completely possible to design planes that handle all but the most extreme and unlikely edge cases. The problem here isn't that passengers didn't have a Rube-Goldberg escape route, but that Boeing made some serious design errors - and then apparently tried to cover them up.

russdill 8y ago

Go look up some of the recent airliner incidents. It doesn't appear that parachutes would have helped very many, if any. To make matters worse, such a feature would greatly cut down on passenger numbers per plane, which means more flights, which means more accidents. https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_commercial_aircraft https://en.wikipedia.org/wiki/List_of_accidents_and_incident...

vfinn 8y ago
True. Quite many incidents / accidents during the takeoff. Also, crashes into mountains seem common as well. Not sure what the reaction time is in those cases.

amelius 8y ago

Halfbaked idea: perhaps you could make an airbag that you can wear as a garment, and which you inflate if a crash is imminent. Of course, if everybody in the plane wears one, you could have a space problem, but it would provide extra protection by compartmentalization.

tialaramex 8y ago

The mass involved is far too great to be practical for parachute descent. Also, when are you going to "eject" this parachute module? Most serious accidents happen in the phases of flight very close to the ground, take off and landing. But just deploying a parachute won't work when you're so close to the ground. Try it for yourself if you like, buy a parachute, attach it, and jump off a ten story building. Your corpse will be surrounded by as-yet undeployed parachute fabric at the bottom. A fighter jet gets around the being too close to the ground problem by adding a rocket motor. When you "eject" the rocket shoots the pilot's entire seat into the sky first. If you want to eject the entire cabin you're going to need a very big rocket. Not crashing the plane is better. The goal is to not crash the plane whereupon this is all irrelevant. If you're wondering why that wasn't enough for fighter jets the answer is that the other guy's fighter jet is trying to shoot yours out of the sky. Planes don't fly once you put enough bullets into them. How many is "enough"? Well it may be prudent to eject before getting a firm answer. Small prop planes can fit parachutes that try to save the whole fuselage, these have been seen to work at least sometimes, but they're very much a last ditch, they are expensive and they're only "practical" (if that's even the right word for something so expensive and relatively ineffective) for small planes.

marsRoverDev 8y ago

Because said system would be very heavy, and probably on balance it would result in more crashes due to an increased number of failure modes.

DuskStar 8y ago

I think zero-zero ejection seats are a good point of comparison here. These are the state-of-the-art ejection seats used by US fighters and bombers, designed to function from a dead stop on a runway. That's what you'd need for this to be useful in the flight regime most accidents occur in. Unfortunately, ejection seats suck to use. Like, mild chance of killing you, very high chance of breaking bones, almost certain to make you a few inches shorter from compressing your spine levels of suck. This is assuming that you don't hit anything on the way out, of course - and don't land in the fireball. And that's with trained, fit pilots who are expecting the ejection. Can you imagine what happens to Grandma who's started to lose bone density? Or the baby on their mother's lap? And that's before you start considering the issues with having that many parachutes and rockets in close proximity, or the weight. So that's why planes don't have features to save these people.