Airliner Safety

[Airbrush]

BTW, I'm no longer able to quote when I reply, or copy and paste. Does anyone have this problem?

 

I was getting off topic on "Better Black Boxes", so here is the continuation.

 

Statistically, airliners are a very safe mode of transportation.

 

My question is: How many fatalities occurred during the CRUISING phase (not takeoff and landing) of all flights worldwide, during the past 10 years? My assumption is that during those events, lives COULD have been saved. They could also land in the freezing South Indian Ocean, and eaten by sharks, or on the side of a mountain, but they would have a CHANCE at survival.

 

There were some, according to the stats that Swansant provided in "Better Black Boxes", and many of those lives could have been saved by having a parachute escape system in the plane.

 

If an airline installed an escape system, they could boast about it, and people may pay attention and prefer that airline, even though chances of needing to use it are miniscule, it would have a psychological impact on the average person. If one airline gets more business by having this system, other airlines would follow.

 

The Titannic was unsinkable, so had few life rafts.

 

This IS a plan B, since plan A is always to NOT CRASH.

Edited March 25, 2014 by Airbrush

[Greg H.]

Since I have no idea how many airliner related fatalities occurred in the last ten years, I am going to address the financial issues of adding a mass ejection system to an aircraft.

 

Let's start by remembering that airliner take off weights are fixed. Exceed the maximum allowed weight and the plane simply will not fly - it won't be able to generate enough lift to get airborne. That fixed weight is then divided into two categories - revenue weight, which is the weight of people and cargo that the airline is being paid to move, and tare weight which is everything else, including the weignt of the plane itself, any fuel on board, as well as the weight of the crew. You can express the total weight as

 

[math]W_{tot} = W_{rev} + W_{tar}[/math]

 

It's pretty simple - if you increase the tare weight, by adding an ejection sytem (even parachutes), you lower the available revenue weight. Since the airlines are already strapped for cash because they underprice the cost of flying (thank you government subsidies), that would result in a rise in the per-seat cost of a ticket.

 

Which would be fine if we can make the assumption that the total amount of passengers and cargo remained stable. Unfortunately, we can't - increased costs of tickets would inevitably price some people and businesses out of the market, forcing them to switch to cheaper (albeit slower) alternatives. So while Supersafe Airlines might grab a larger slice of the business pie (which is, in and of itself an assumption) because of their ejection system, even with the higher prices, the overall pie is going to be smaller, so there's no guarantee it will actually increase profits. And the more you raise prices, the fewer people will actially be able to afford to fly Supersafe Airlines. No airline is going to risk pricing itself out of an already cut-throat market for an optional safety device.

 

In all probability, the only way you'd ever see something like this is if it became mandated by the FAA, or some similar body. Keep in mind that airlines want to maximize profit, and that means maximizing revenue weight flown per operating hour - it's why you rarely see a half full airplane anymore, even on the red-eyes and off-peak days. Unfortunately, while maximizing profit means minimizing flight risks, which can translate to increased passenger safety, minimized flight risk is the not necessarily the same thing as maximized individual passenger safety, and most airliner safety features are there because they are required to be there by regulation, not out of any feeling of goodwill by the airline.

[swansont]

 

My question is: How many fatalities occurred during the CRUISING phase (not takeoff and landing) of all flights worldwide, during the past 10 years? My assumption is that during those events, lives COULD have been saved. They could also land in the freezing South Indian Ocean, and eaten by sharks, or on the side of a mountain, but they would have a CHANCE at survival.

 

 

 

Overall, 16% of fatalities. It's not broken down in terms of when in the link.

 

http://www.statisticbrain.com/airplane-crash-statistics/

[Enthalpy]

Last time I had a parachute (in a glider, where mass counts as well) it weighed like 10kg, just from the impression. It didn't have a raft, sweet water and vitamines.

 

That would make the ticket 1/8 more expensive. A horrible lot. Engine manufacturers invest many millions to save 1% fuel.

 

Not only the airlines, as well the passengers would answer "1/8 is too much for an improbable accident where the parachute probably wouldn't save me".

[John Cuthber]

On roughly two thirds of the earth's surface, a parachute would ensure you drowned rather than being killed by the impact.

[CaptainPanic]

On roughly two thirds of the earth's surface, a parachute would ensure you drowned rather than being killed by the impact.

 

But judging by the list of airplane crashes, planes crash mostly over land, especially shortly after take-off or right before landing. This is also suggested by the statistics that swansont linked to: only 16% of the fatalities occur during cruise. Take off and landing are obviously over land. Climbing and decent are over land or at least near land (and in that case, a soft landing on water is definitely an option, as rescue is a realistic scenario).

 

That said, I am not sure I ever want to experience a parachute deployment in an aircraft at cruising speeds. The G forces would probably be rather dangerous too. We can also try to tackle that through more technological advances. Or we could just argue that we're making a lot of fuss about something that is really safe already.

[Ophiolite]

The default position of most members of the public in relation to parachute jumping is that it is foolish to jump out of a perfectly serviceable aircraft. What is not recognised is that a substantial proportion of those people probably also think it is madness to jump out of a non-serviceable aircraft. If the plane is sufficiently in control to permit the safe exit of several hundred passengers, then it is likely in sufficient control to be landed with less risk to life than a mass ejection.

 

Fundamentally, the idea is crazy.

[Airbrush]

Very interesting, thanks for the thought on this subject.

 

Hopefully, they will continue to build planes better and stronger, use redundant safeguards, and have more and/or better inspections in the future, and let's hope for the best. Maybe they can carry cyanide pills for anyone who doesn't want to burn to death or something like that.

 

Don't they already have the ability to knock all the passengers out with a sedative gas?

Edited March 27, 2014 by Airbrush

[Greg H.]

 

 

Don't they already have the ability to knock all the passengers out with a sedative gas?

No, they just reduce the cabin pressure until you pass out (or die) from lack of oxygen. At the heights that airliners normally cruise at, the air is too thin to support human life.

 

I suppose you could add something to the pressurization system that would pump something through the plane if you wanted to, but I doubt it's standard equipment.

[swansont]

 

Don't they already have the ability to knock all the passengers out with a sedative gas?

 

That sounds like a low-budget terrorism movie plot. The ability to make this end horribly is a much greater risk than the plane crashing.

[CaptainPanic]

Don't they already have the ability to knock all the passengers out with a sedative gas?

 

The reason that everybody may get sleepy on an airplane is probably because they reduce the cabin pressure a little (hence the popping ears during climbing and decending). You just get a little less oxygen, and you don't get enough time to adapt to that. Less oxygen may mean more sleepiness. But then again, people also fall asleep on a bus.

 

The reason the airplane is designed to lower the cabin pressure is to lower the pressure difference between the inside and outside of the airplane. The lower the difference in pressure, the lighter they can make the fuselage. Apparently, the airplane manufacturers don't talk about cabin pressure, but about 'cabin altitude' (i.e. the pressure that you have at a certain altitude). According to this wikipedia article, and this article about the latest developments, cabin altitude in normal airliners is 6,000-8,000 ft (1.8-2.4 km altitude), which according to the engineering toolbox translates to a pressure of around 80 - 75% of the pressure at sea level. And if you're really interested, this article describes and explains some ymptoms you can experience in an airplane at altitude.

 

But this is going too far now, and I am going off topic, and for all I know, I may even have misunderstood your post.