Why a detachable cabin probably won't save your life in a plane crash

January 28, 2016 by Herve Morvan, University Of Nottingham, The Conversation
Why a detachable cabin probably won't save your life in a plane crash
Chocks away! Credit: Vladimir Tatarenko/YouTube

Falling out of the sky may well be most passengers' worst fear when they board a plane. With this mind, a Ukrainian inventor has proposed building airliners with detachable passenger cabins that could separate from the rest of the plane and parachute safely to the ground in the event of an emergency.

This may sound like a reassuring idea for those who find flying more of a terrifying ordeal than an exciting way to start a holiday. But as someone with a keen interest in and technologies, I found the plan a bemusing distraction. Not only would such a design be prohibitively expensive, it would also be unlikely to save any lives in all but a very few airline disasters.

While the video proposal shows the detachable cabin deploying on a plane experiencing engine failure, it should first be noted that crashes due to this problem are exceptionally rare. Systems and power failures have accounted for less than 3% of all fatal accidents in the past 10 years. From the beginning the argument did not stack up.

An aircraft is most vulnerable during take-off and landing because it is closer to the ground (its biggest obstacle), and is travelling at low speeds and therefore is harder to manoeuvre. According to statistics from Boeing, almost three-quarters of deaths from plane crashes between 2005 and 2014 occurred during these phases of flight. But this is the time when a detachable cabin would least likely be successful at saving lives. Being closer to the ground would give the pilot much less opportunity to jettison the cabin following an incident and if it were detached it could well land in a built-up area.

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Nevertheless, slightly over 1000 lives have been lost in the past ten years due to accidents during the cruise phase of flight, when a detachable cabin might have been of most value. But even during this stage of flight, it is difficult to see that the technology would often be effective.

Most aircraft accidents – as many as 80% – are due to human error, with the most common being loss of aircraft control and flight into or towards terrain. A detachable cabin would probably be impossible to deploy safely if the pilot had lost control of the plane, or if it was about to fly into the terrain.

Quick thinking

Even in cases where the pilot can respond calmly and quickly to something that wasn't their fault, it is a struggle to see how a detachable cabin could usually play a significant role. Take US Airways flight 1549, which saw pilot Chesley B Sullenberger land the plane in the Hudson river in New York after birds flew into the engines at take-off. Though manufacturers cannot prepare for every scenario, engines are tested for bird ingestion and designed to survive them, at least for a while. Aircraft can also continue to ascend with one engine down. In this case, however, the captain was particularly unlucky to lose all power and was therefore unable to fly back around for an emergency landing at an airfield. What would a detachable cabin have resolved there? At low altitude it is unlikely it could have been deployed in the first place. Then, what if the cabin had landed on the city?

Why a detachable cabin probably won't save your life in a plane crash
Wishful thinking? Credit: Vladimir Tatarenko/YouTube

Practically, there is also the technical complexity of actually building such a system, the mechanisms and bolts to secure the cabin but also allow its safe release in flight. You can add to this the service issues and maintenance challenges.

In addition, there is the excess weight of the proposed system. Weight is everything for aircraft manufacturers. Every extra kilogram requires more thrust and a higher fuel burn.

Despite these flaws, this actually is not the first time a detachable cabin system has been envisaged. Following the Challenger shuttle disaster in 1986, designers on the European Hermes space shuttle programme looked at the possibility but found it hugely expensive as well as impacting what the shuttle could carry. The system ended up being one of several fatal blows to Hermes and the shuttle was never built.

More recently, Airbus patented an "Aircraft Pod Concept" in late 2015. This involves switching one cabin full of passengers or cargo for another at the airport in order to reduce turnaround times. This is only a generic concept rather than a full design and is probably based on the idea that the extra weight and fuel costs would be covered by the money saved from the shorter docking time, not on being able to jettison the pod in case of accident.

However disappointing it may seem to those with a fear of flying, the parachuting cabin concept would just be too expensive to make a reality and is unlikely to appear soon. But passengers can still rest easy thanks to the ever-improving safety record of the airline industry.

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Eikka
2 / 5 (4) Jan 28, 2016
Most aircraft accidents – as many as 80% – are due to human error


Most of those, I claim, are actually hardware malfunctions where the sensors or computers have failed or have a design flaw, and have left the pilots scrambling with conflicting or erroneous information in a panic situation.

The humans - to which the errors are blamed on - are the last to touch the controls after the autopilot has simply given up and the accident has already become more or less unavoidable given the circumstances.

This bias towards blaming the people instead is a result of the airlines and airplane manufacturers reluctance to admit that the hardware itself, and their maintenance procedures and safety precautions etc. are unreliable. The pilot is the easy scapegoat.

That in turn fosters an unwarranted trust in technology, where in the public imagination the computer cannot err and even when it does it's always someone else's fault.
Zzzzzzzz
3.7 / 5 (3) Jan 28, 2016
you claim......
Torbjorn_Larsson_OM
5 / 5 (1) Jan 28, 2016
It was interesting to read this proposal a few weeks after a work discussed detachable cabins as the most effective way to load/unload passengers. (I.e. they could do so way before the plan lands and take off.)

I dunno about the weight problem, but since plans have flammable fuel close a possible solution to low height accidents would be to use rockets like similar ejection seats/capsules of military jets do for much the same reason. You could even have the cabin launch topside if you pull the parachutes later.
ab3a
5 / 5 (1) Jan 28, 2016
This is not a new proposal. People proposed such things back in the 1960s. It was a foolish idea then and it hasn't gotten any better with age.

Many accidents are in fact made worse by human error. Notably, airline pilots from countries without a strong general aviation community have almost no feel for how an aircraft should fly. So they make some appallingly basic mistakes because they have no situational awareness or even seat of the pants feel for flying.

The cause in my opinion is complexity. This solution doesn't fix that. Yes, we should have automation, but it should NEVER hide anything from the pilot, nor should it do anything unexpected. The pilot should be thinking ahead of the aircraft every step of the way.

Captain Sullenberger was experienced in all sorts of aircraft from fighter jets to gliders. So when the engines failed, he knew exactly what he had to do. If only we could clone him...
NIPSZX
not rated yet Jan 28, 2016
Great research!
freeiam
not rated yet Jan 29, 2016
That's a real arrogant tone you have against someone who tries to solve a problem.
Your hammering on the 'fear' people have, but it's actually very real.
Instead of dismissing the solution, why not be constructive and think of a an alternative.
By the way securing a construction that big isn't that difficult to do, it can be done with explosive bolts like they do in the space industry (first and second stage are bolted together in this way).
Another much better solution would be to make commercial airliners a bit more robust in the start and landing phase. This can be done by adding (relatively) small thrusters that run one kerosine and air that kan support or even land the plane vertically when needed.
(Think also about the Hawker Harrier way of flying but with rickets.)
This is doable and wouldn't add to much weight and would be similar to SpaceX's approach for the dragon capsule (maybe order the engines from them).
Eikka
not rated yet Jan 29, 2016
Many accidents are in fact made worse by human error.


I'm not sure how one can judge an accident "worse" when everyone in it dies anyways.

There's plenty of airline accidents that could have been avoided if the hardware hadn't failed miserably, while there are fewer that could have been plausibly avoided if the pilots hadn't also failed.

When you read the accident reports, it usually starts with identifying a host of hardware failures, including computer and sensor failures, software bugs and glitches, but then ends up blaming the pilot for adding to the problem (human error), where in reality the pilot would likely have had to apply almost superhuman effort and presence of mind to the situation to have any chance of saving the flight - all the way to things like punching the co-pilot senseless to stop him from pulling his stick.

Sometimes it happens, usually not.
Eikka
not rated yet Jan 29, 2016
So there's this weird double standard I see.

We say the computers are better flyers and drivers and thinkers than we are, and we ignore it whenever they fail, and instead look up to the human operators with the expectance of damn near omniscience and omnipotence, and when they fail we say "well if that had been a computer it would have saved the day".

But it wasn't the computer, because the autopilot had already failed and said "pull up" to the pilot when the airplane was already in a stall.
freeiam
not rated yet Jan 29, 2016
Your right Eikka, I do think pilots get the blame very easily and accidents are caused by the horrible design of the cockpit and deafening and confusing alarms that go off.
(Cognitive science shows that this kind of feedback is always negative.)
Only a few very special people can make decisions in such circumstances; but even that is sometimes impossible with conflicting data.
What's missing is redundancy, in some of the cases an iPhone with a flight program on could have saved them, also forward radar is still missing on modern aircraft. So they have to rely on external data. It also seems that GPS isn't used as it should, for example by determining the exact location of the plane and thereby its surroundings (so a wrong radio beacon wouldn't confuse the approach).
ab3a
5 / 5 (1) Jan 29, 2016
Another much better solution would be to make commercial airliners a bit more robust in the start and landing phase.


They already are. If you made them any heavier, they wouldn't be economical to operate.

This can be done by adding (relatively) small thrusters that run one kerosine and air that kan support or even land the plane vertically when needed.


Uh, the fuel is in the wings. If you leave the wings behind, you don't have fuel.

This is doable and wouldn't add to much weight and would be similar to SpaceX's approach for the dragon capsule (maybe order the engines from them).


At what cost? To rescue how many people from how many accidents? Would it have saved The Asiana airline crash in San Francisco? Nope. Would it have saved AF447? Nope --not with the pilots so blissfully unaware of their situation.

Ultimately, it does come down to money. Wouldn't you rather see it spent on something that saves more people?
ab3a
3 / 5 (2) Jan 29, 2016
Only a few very special people can make decisions in such circumstances; but even that is sometimes impossible with conflicting data.

I am an instrument rated private pilot. Pilots train for this sort of scenario. I was co-pilot in an airplane at night with our only engine about to fail. We fell back on our training. We were calm and didn't lose our cool. We landed safely, without incident. Only AFTER we reported that we were okay and went back to look at the airplane did we get weak knees, realizing what we had just been through. It's all about training, not "special people."

What's missing is redundancy.

Nonsense. There already are numerous redundancies, even in small aircraft built since the 1970s. The problem in modern aircraft is figuring out what isn't working the way it should. I've had instruments fail in flight. It's no big deal --If you train for it. But many pilots in many countries do not. They're even more ignorant than many bus drivers.
fossilator
5 / 5 (1) Jan 31, 2016
Essentially the same idea, U.S. Patent 4,699,336, granted 10/13/1987 "Airplane Safety Body Passenger Compartment" ( http://www.patent.../4699336 ).
antialias_physorg
not rated yet Feb 01, 2016
I'm seeing a problem with this (apart from being only applicable to a minority of dangerous situations)

Jettisoning the cabin is an automatic death sentence for the pilot/co-pilot. I can't see the rest of the plane being stable - even in optimal weather conditions.
So any pilot would try to save the plane as long as possible (i.e. probably way past the stage where a jettison would save the passengers).

And we're talking about a plane in dire straits here (Flat spin? Wing torn off? Nosedive? Stormy weather? What about when this is jettisoned over an ocean? Will it sink?) Does it work in all these conditions?
As someone who isn't comfortable on planes at all I think this isn't going to be more than a PR gag to get people like me to chose their airline (OK, not like me...because I know most accidents happen during takeoff/landing...I'm not worried during flight)

The video might as well have the "Aperture Science" logo.

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