Huge airbags for each passenger during a flight: is it feasible?

[Myuncle]

Since the parachutes may be too heavy for each seat, why they don't provide each passenger with inflatable balloons? The airbags would be strapped one in the front and one in the back, front pack plus back pack, this wouldn't assure 100% survival of the victims, but at least it can soften the impact on the ground.

Edited June 3, 2014 by Myuncle

[Sato]

Since the parachutes may be too heavy for each seat, why they don't provide each passenger with inflatable balloons? The airbags would be strapped one in the front and one in the back, front pack plus back pack, this wouldn't assure 100% survival of the victims, but at least it can soften the impact on the ground.

 

I don't know how well balloons would do in the way of exploding jet fuel and speeding shrapnel.

[CaptainPanic]

What makes you think that a balloon will be lighter? I assume you want to fill it with pressurized gas? Such gas cylinders are really heavy. If you want to slow down the fall of anyone from an airplane, I would recommend a parachute.

 

However, most airplanes seem to crash at take off or landing, which gives the passengers no time to leave the aircraft, as everything happens very fast. And if something goes so very wrong with an airplane that you want to leave it mid-flight at cruise altitude, I agree with Sato that fire and shrapnel are an issue. Also, the sub-zero temperatures, the raging 800 km/h wind and the very thin air are a real concern.

[Phi for All]

If the airlines are going to spend that kind of money on safety, I'd rather it be spent preventing situations where you'd need an airbag.

[Myuncle]

 

I don't know how well balloons would do in the way of exploding jet fuel and speeding shrapnel.

If you leave the airplane in mid air there are no shrapnels, and you activate the balloons with a button before touching ground of course...

What makes you think that a balloon will be lighter? I assume you want to fill it with pressurized gas? Such gas cylinders are really heavy. If you want to slow down the fall of anyone from an airplane, I would recommend a parachute.

 

However, most airplanes seem to crash at take off or landing, which gives the passengers no time to leave the aircraft, as everything happens very fast. And if something goes so very wrong with an airplane that you want to leave it mid-flight at cruise altitude, I agree with Sato that fire and shrapnel are an issue. Also, the sub-zero temperatures, the raging 800 km/h wind and the very thin air are a real concern.

If they crash at landing or take off then you are right, I thought most accidents happened in mid air. I imagine simple compressed air, the same used for airbags, wouldn't be that heavy.

Edited June 3, 2014 by Myuncle

[Phi for All]

If you leave the airplane in mid air there are no shrapnels, and you activate the balloons with a button before touching ground of course...

Am I still conscious after having been ejected at 30,000 feet? Can I push the button?

 

If they offer me a choice like they used to with the meal, I'll take the parachute for mid-air departures. Less bouncing.

 

If they crash at landing or take off then you are right, I thought most accidents happened in mid air. I imagine simple compressed air, the same used for airbags, wouldn't be that heavy.

A couple hundred small tanks of it would be.

 

What's the average speed on take-off and landing? Would a standard airbag handle those speeds?

[Myuncle]

Am I still conscious after having been ejected at 30,000 feet? Can I push the button?

 

If they offer me a choice like they used to with the meal, I'll take the parachute for mid-air departures. Less bouncing.

 

A couple hundred small tanks of it would be.

 

 

If they can eject you at 30000 feet, it means the pilot can wait and eject you at 5000 feet.

What's the average speed on take-off and landing? Would a standard airbag handle those speeds?

that's a good question.

[Phi for All]

If they can eject you at 30000 feet, it means the pilot can wait and eject you at 5000 feet.

 

I was picturing an automatic system, triggered by collision like any airbag. In this event, the pilot would either be dead or would have enough on his plate to worry about without adding another crucial step.

 

But now you should be able to figure out what kind of forces you're dealing with. Calculate a free fall from 5000 feet and see if an airbag would let you survive. Is the airbag part of the seat, what parts detach with you, how much extra weight goes into the "balloon"? Factor all that in and see if the weight and the cost are less than a parachute.

 

I flashed on an old George Carlin joke (adapted for the thread): "My airbags and I got ejected from the exploding airplane, and I wound up in the Mayo Clinic. The doctor said it was a hell of a bounce!"

[ACG52]

 

What's the average speed on take-off and landing? Would a standard airbag handle those speeds?

For a 737, the range of take-off speeds runs between 140 kts and 165 kts. Landing speeds are a little slower.

[Phi for All]

For a 737, the range of take-off speeds runs between 140 kts and 165 kts. Landing speeds are a little slower.

 

Thanks for that. I tried looking up how much weight an airbag can handle, but that leads me off into a different kind of airbag, one used for big truck suspension.

 

I wouldn't think a standard auto airbag would be rated to help someone survive a crash at 190mph. I'm probably wrong, but isn't there going to be a point where you're just going too fast for the materials and process to save your life?

[Greg H.]

As it turns out, someone has already done a study. Basically anything above 25 mph reduces the effectiveness of the airbags, according to the study.

 

http://www.ncbi.nlm.nih.gov/pubmed/16210197

 

 

Abstract

An investigation was conducted to estimate the effectiveness of air bags as a function of velocity. The study consisted of three parts: a theoretical idealization, an analysis of National Automotive Sampling System/Crashworthiness Data System (NASS/CDS), and a reanalysis of previously published Fatality Analysis Reporting System (FARS) data. The theoretical analysis looked at idealized risk curves as a function of velocity; assuming that the air bag offers a benefit for both belted and unbelted occupants. Analysis of the NASS/CDS data looked at the effectiveness of air bags as a function of velocity for Maximum Abbreviated Injury Scale (MAIS) 3+ injuries. The reanalysis of the previously published FARS data looked at the effectiveness of the air bag as a function of velocity for fatalities. The theoretical analysis indicates that the air bag effectiveness should be greatest at the low velocities. The field data analysis of both NASS/CDS and FARS were consistent with the theoretical analysis, indicating that air bags are most effective at the lower velocities, below 40 kph (25 mph), for both belted and unbelted occupants. Although it was not possible to estimate a different effect for belted and unbelted for fatalities using FARS, it was possible for MAIS 3+ using NASS/CDS. For unbelted occupants the effectiveness goes to zero or becomes negative above 40 kph (25 mph) for MAIS 3+, and for belted occupants the effectiveness stays positive but with significantly lower magnitude for speeds above 40 kph (25 mph).

[Cap'n Refsmmat]

What makes you think that a balloon will be lighter? I assume you want to fill it with pressurized gas? Such gas cylinders are really heavy. If you want to slow down the fall of anyone from an airplane, I would recommend a parachute.

Airbags usually use chemical gas generators instead of pressurized tanks, since you don't want to keep a pressurized air tank in your car all the time.

 

But yes, I feel like a > 200mph impact into the ground probably destroys the structure of the aircraft so much that the airbag can't be much help.

 

Ejection seats would be great, but you wouldn't be able to use a laptop safely (it'd be blasted off your lap and into the guy behind you upon ejection) or move around much, and you'd have to be strapped in much more securely. And have an oxygen mask on at all times. And so on.

[J.C.MacSwell]

Airbags usually use chemical gas generators instead of pressurized tanks, since you don't want to keep a pressurized air tank in your car all the time.

 

But yes, I feel like a > 200mph impact into the ground probably destroys the structure of the aircraft so much that the airbag can't be much help.

 

Ejection seats would be great, but you wouldn't be able to use a laptop safely (it'd be blasted off your lap and into the guy behind you upon ejection) or move around much, and you'd have to be strapped in much more securely. And have an oxygen mask on at all times. And so on.

Probably best to wait until you land/crash on the ground in any event, though good point, some level of electronic entertainment must be maintained at all times these days...

 

Seriously, what is the smallest parachute that could be deployed to allow a good chance of survival? A balloon would have to be considerably larger to create the same drag at the same speed, and have to be underneath you on landing to provide additional protection...perhaps some combination would work? The seats already (unless this has changed) serve as emergency flotation devices.

Edited June 4, 2014 by J.C.MacSwell

[CaptainPanic]

Airbags usually use chemical gas generators instead of pressurized tanks, since you don't want to keep a pressurized air tank in your car all the time.

 

Yeah, I thought that our OP wanted to gently float down using a balloon (like a helium balloon). Now I understand that he just wants to fall down to earth at terminal velocity, and then use an airbag to soften the inevitable crash.

 

Mythbusters tested using a life raft for surviving a fall (which worked, as the raft was huge). And if you google around for 'paratrooper airbag', there are a number of hits. It seems to me however that the entire world still prefers parachutes, not airbags.

 

Personally, if an airline starts handing out parachutes or airbags before boarding the plane, I think I'd just have another beer in the airport lounge, and let the plane depart without me.

[Myuncle]

Now I understand that he just wants to fall down to earth at terminal velocity, and then use an airbag to soften the inevitable crash.

Yes, that's what I was thinking about. A parachute is basically too heavy the way it is. They could make disposable parachutes also, less efficient, but they could potentially save your life, for example they could use some sort of expandable foam spray that is going to fill a huge inflatable umbrella.

Edited June 4, 2014 by Myuncle

[CasualCause]

As it turns out, someone has already done a study. Basically anything above 25 mph reduces the effectiveness of the airbags, according to the study.

 

http://www.ncbi.nlm.nih.gov/pubmed/16210197

 

Apparently I can confirm this.

I am working at an automotive safety company. It is general knowledge that an impact above 25-35 mph is very likely lethal and protective measures such as airbags are not to be relied on.

 

 

[ACG52]

 

 

A parachute is basically too heavy the way it is.

Light weight parachutes run between 10 and 12 lbs.

[Myuncle]

Light weight parachutes run between 10 and 12 lbs.

 

Why not to pack a light weight parachute inside the seat then? When it's time to escape, you detach the seat and carry it away with you.

Edited June 5, 2014 by Myuncle

[ACG52]

And stand in line to get out the door while the plane plummets towards the ground.

[Klaynos]

 

Why not to pack a light weight parachute inside the seat then? When it's time to escape, you detach the seat and carry it away with you.

Cost and weight which (is cost again). No airline would go for it without a legal requirement, no aviation authority would go for it because of the lack of benefit. Chutes only work above a certain height. You don't want to jump out of an aircraft at 300 kts even if you could stay conscious at cruise altitudes and that's only if you had enough warning to get out.

[Dekan]

 

Why not to pack a light weight parachute inside the seat then? When it's time to escape, you detach the seat and carry it away with you.

 

Or - instead of giving each seat an individual parachute - couldn't all the seats be enclosed within a kind of "passenger-tube". This would be like a big cylinder, sealed off from the rest of the plane.

The cylinder would have 3 huge parachutes on it - one at each end, and one in the middle. Thus enabling a stable descent towards the ground, without tipping over.

 

The cylinder would be carried by the plane, but would be a separate structure - like the weapons-pod of the B-58, or the cargo-section of Thunderbird-2.

So it could be dropped away, if an emergency happened - such as all the engines failing, or a wing breaking off.

 

And in case the emergency happened close to the ground, where the parachutes wouldn't have time to open properly, the cylinder could have powerful retro-rockets fitted to its underside. These would fire automatically just before hitting the ground - like in the Soyuz capsule, thus providing a soft-landing.

 

All the above could be done, but it won't be, and quite rightly so. Because it would cause enormous increases in the cost of air-travel, would very rarely be used, and absurdly exaggerates the value of individual human lives.

 

With 7 billion+ of us on the planet, we can afford to lose a few in occasional air-crashes. Let's not get too obsessed by a sense of individual self-importance!

[CasualCause]

Cost and weight which (is cost again). No airline would go for it without a legal requirement, no aviation authority would go for it because of the lack of benefit. Chutes only work above a certain height. You don't want to jump out of an aircraft at 300 kts even if you could stay conscious at cruise altitudes and that's only if you had enough warning to get out.

 

 

 

Or - instead of giving each seat an individual parachute - couldn't all the seats be enclosed within a kind of "passenger-tube". This would be like a big cylinder, sealed off from the rest of the plane.

The cylinder would have 3 huge parachutes on it - one at each end, and one in the middle. Thus enabling a stable descent towards the ground, without tipping over.

 

The cylinder would be carried by the plane, but would be a separate structure - like the weapons-pod of the B-58, or the cargo-section of Thunderbird-2.

So it could be dropped away, if an emergency happened - such as all the engines failing, or a wing breaking off.

 

And in case the emergency happened close to the ground, where the parachutes wouldn't have time to open properly, the cylinder could have powerful retro-rockets fitted to its underside. These would fire automatically just before hitting the ground - like in the Soyuz capsule, thus providing a soft-landing.

 

All the above could be done, but it won't be, and quite rightly so. Because it would cause enormous increases in the cost of air-travel, would very rarely be used, and absurdly exaggerates the value of individual human lives.

 

With 7 billion+ of us on the planet, we can afford to lose a few in occasional air-crashes. Let's not get too obsessed by a sense of individual self-importance!

Exactly. We can afford such "risks", however cruel I may sound. Being an engineer, you have to know how far you can go with feeding unproductive demands at Mother Earths expense.

Strictly from resource perspective, the human resource is the cheapest among all.

Edited June 6, 2014 by CasualCause