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Effect of passenger position on crash injury risk in aircraft (2015) [pdf] (faa.gov)
63 points by susam on June 14, 2024 | hide | past | favorite | 87 comments


One of the great things of the last ~25 years is the small n in regards to commercial aircraft fatalities. This report is dated 2015 but I wonder if it would be any different a decade later. In the prior 50 years, plane crashes were, maybe not common, but something you’d read about every month or so.

The only emergency landing I’ve been in where the crew briefed us on position and checked us was hands on the back of the seat in front. Luckily it wasn’t a crash and the fire was quickly contained on the ground. Turned out the shoe removal was the most inconvenient but perhaps the most useful (evacuation slides worked, but then we were on hot tarmac without shoes).

What astonished me the most was how everybody went along and didn’t complain. This was almost 35 years ago —- I wonder if that would still be the case. These days I have seen pictures of people sliding down the evacuation slides with hand luggage!


I am not convinced about the wisdom of forbidding to take the hand luggage.

It is true that there are many people who have a big and awkward hand luggage or who need a very long time to recover their luggage from overhead.

There are also many other people who are able to recover their hand luggage from the overhead in less than a second and in much less time than most other passengers are able to just stand up.

I do not see why such passengers should be penalized, even if they would certainly not slow down the evacuation. Losing the documents and data from the hand luggage may cause very serious problems that could need many months of work for solving and passing through many unpleasant experiences until then.

The only argument against this that is correct, is that like in every other domain people would self-assess their own abilities too optimistically, so even those who are slow would believe that they can retrieve their luggage fast enough to not hinder the evacuation, but then they would be proven wrong.

Perhaps the passengers should pass a test of hand luggage retrieval speed, before the flight, in order to be pre-approved for keeping their hand luggage in the case of an emergency landing :-)


> The only argument against this that is correct, is that like in every other domain people would self-assess their own abilities too optimistically, so even those who are slow would believe that they can retrieve their luggage fast enough to not hinder the evacuation, but then they would be proven wrong.

This is they key. Not only overestimating their speed in taking down the luggage, but also other passengers overestimating how much time they have to safely get off the plane.

Take Spantax Flight 995, for example. Almost everyone survived the initial crash landing, but dozens died from smoke inhalation. Most of those who died were seated in the rear of the plane, where there was traffic in the aisles due to one or two people grabbing luggage from the overhead bins. There is an account from a survivor from the rear of the plane who only managed to escape because he climbed over the seats to get around the traffic. Most other passengers in the area were content to wait, not realizing how quickly the smoke would spread and turn lethal.


For the case I wrote about, on one side of the plane the ground crew was spraying foam on the wing and engines; everybody had to exit on the other side. FAA wants the entire plane emptied in 90 seconds.

In addition whatever you're carrying could injure you during decent (especially at the end - FAA is OK with people breaking ankles) or worse piece the chute. The crew came by and took everybody's shoes and stowed them in the overheads before they checked our brace positions. They also moved me and two other guys in our 20s into the exit row and ejected the three people already there.

Our cabin could have been full of smoke, or worse (luckily, it was not at all like that) and so do you think they want to try to explain a decision tree to a bunch of panicked passengers?


> Losing the documents and data from the hand luggage may cause very serious problems that could need many months of work for solving and passing through many unpleasant experiences until then.

Rather go through the months of work solving problem and having unpleasant experiences than be dead.

And you can be confident anyone holding me up in an emergency for mere documents and papers is going to experience immediate unpleasantness that they aren't going to solve.


The fundamental problem is mis aligned incentives and consequences.

It’s really unlikely YOUR luggage will impact YOur escape much at all, at worst you can abandon it at almost any point.

The consequence of injury will be for those around you, and possible delay for people behind you. But not really YOU.

For “important papers” I suspect there is some evaluation of how much they are willing to risk the lives of those other people at the back of the plane.

Rule should be if you bring your luggage you are handcuffed to the plane until the last person leaves. I think in older times you would have more severe consequences.


I'm sure that less than second added a hundred times over can save some lives, plus in a tighter situation, bags behinds your back or in your hand will take up additional space that could accommodate another human.


The seconds are not added, because the corresponding activities are concurrent.

I am pretty sure that except for the people adjacent to the emergency exits, the others will have to wait their turn for a much longer time.

A backpack carried on the breast would not occupy space in which another human could have stayed.


As someone who has spent a lot of time defining and enforcing processes (yay), it is far easier and more understandable to adopt a hard rule for this sort of thing. You don't want people to be debating whether or not their backpack is the acceptable size to include, while someone else's laptop case is not. Then you have someone saying that they are allowed to take their backpack, but it is in the overhead bin one row behind them, so could you just pass it to me...

For life or death situations, you need to have short clear rules that are easy to follow.

Remember, you will only actually lose your stuff if the plane is destroyed. If the plane is in the middle of being destroyed, just get out and be glad you are still alive!


> it is far easier and more understandable to adopt a hard rule

Looking at this thread, we might need to put into regulation that taking baggage during an emergency evacuation is criminally negligent. (If someone behind you dies, negligent homicide.)


Agreed. This is your life at risk. This is the lives of others on the plane at risk.

Everything else takes a back seat to those priorities.


> A backpack carried on the breast would not occupy space in which another human could have stayed.

An individual backpack might not displace an individual human but across ~300 passengers those 50 backpacks will displace people.


> The seconds are not added, because the corresponding activities are concurrent

A passenger has practically zero information as to the seriousness of the crash. It could be a doozy. Or there could be a fuel leak waiting to ignite.

> backpack carried on the breast would not occupy space in which another human could have stayed

You're claiming given two lines of people, one wearing backpacks, the other not, that the latter cannot be compressed more than the former?


There are multiple seats per row and only the first person of that row may benefit from the concurrency, as each person gets into the isle for that row they will add those seconds and that is sequential not concurrent. Also you likely haven't been in a trampling crowd situation, bag on a chest doesn't occupy zero space.


It’s not safe to bring down the slide. Going down the slide at all dangerous, people break legs every now and then. But even worse, the person in front of you really doesn’t want your hand luggage flying out of your grip and knocking them out (which can cause a lot of other problems)


That is true for a big case, but not for a backpack carried on the breast.

I agree that the retrieval of any bulky hand luggage should be forbidden.


Frankly, if in a rare life-or-death situation you care about your hand luggage, I'd recommend carefully reflecting on life choices and priorities.


Here, take my hand luggage and go! I'll stay behind..


Eh, I think this is a don't throw the baby out with the bathwater scenario.

You have way more time than you might expect after a plane crash. "Finally, [Captain] Sullenberger walked the cabin twice to confirm it was empty" [1]. If anybody had grabbed their hand luggage (especially from below their seat) they would've still had time to evacuate.

[1]: https://en.wikipedia.org/wiki/US_Airways_Flight_1549#Ditchin...


Different plane crashes are different.

When a Sukhoi Superjet 100 crash landed in Moscow, a fire broke out and fewer than half of the 78 occupants managed to escape the plane on time.

> Aeroflot claimed the evacuation took 55 seconds, though video evidence shows the slides still in use 70 seconds after their deployment. Passengers were seen carrying hand luggage out of the aircraft.

And you think that you're competent to determine whether there is sufficient time or not after the plane just crashed? If I were sitting in the row behind you, I'd much prefer you didn't.

https://en.wikipedia.org/wiki/Aeroflot_Flight_1492


My question is: what could possibly be so important that you want to take it with you to have your hands full in an emergency potential life-or-death situation?


Uh, there's plenty of time to kill while you wait for the people ahead of you to deboard. Grabbing your phone isn't going to kill anybody.

Hell, even when there isn't plenty of time to kill grabbing your phone isn't going to kill anybody. [1]

You can phrase it as "important enough" all you want, but its really just why let an item to go waste unnecessarily.

[1]: https://youtu.be/CtmxTj9pKqg


Most phones aren't comparable to a bag, even a small bag.

Yeah, probably put your phone in your pocket if it's accessible. Keep your wallet in your pocket. If your wallet doesn't fit in your pocket, at least grab your id and payment cards, if they announce a rough landing while on approach and you have time to prepare a bit.


> You have way more time than you might expect after a plane crash. "Finally, [Captain] Sullenberger walked the cabin twice to confirm it was empty" [1]. If anybody had grabbed their hand luggage (especially from below their seat) they would've still had time to evacuate.

But if they had taken their backpack or suitcase, and had dropped it, they could have blocked other people; knocked other people out; broken someone's ankle making them harder to evacuate etc etc.

And this was a calm evacuation. Imagine a fire, low visibility due to the smoke, the sense of urgency, and you trip on some dimwit's suitcase, pushing the people in front of you down, some of them hitting heads, then panic sets in, the path towards that emergency exit is blocked, etc etc etc.

Leave your fucking luggage behind. If everything is fine, it will get to you afterwards. If the plane is on fire, you won't, but you'd also not kill people by not taking it.


Ah I see you like to generalize. This plane was lucky that it didn't burst into flames as soon as everyone exited or worse yet while they were still exiting.


It absolutely is. You have not seen the evacuation slides in person, they are NOT the fun water slides that you have in amusement parks.

You probably will lose grip on the backpack if you just carry it in your hands. And if you have straps behind your back, it's even worse because you can get tangled and delay others' evacuation.


This is life and death… absolute rule is better then “use your judgement” because plenty of people are gonna say “this 10 minute process is definitely just taking 1 second”


If you're really concerned about your valuables, wear them under your shirt, like a passport and card holder against pickpockets. If you're worried about losing data on your devices it's an easily solved problem to start backups today. I've had luck travelling this way against theft.


The discriminant is the following question: what if everybody behaved like me?


Yes, this is first formulation of the “Categorical Imperative”, which asks individuals to act only according to that maxim whereby they can at the same time will that it should become a universal law. This ethical principle is a central concept in the moral philosophy of Immanuel Kant.


I hope we don't travel on the same aircraft.


> Perhaps the passengers should pass a test of hand luggage retrieval speed, before the flight, in order to be pre-approved

Boarding.

It’s a shit show of people doing annoying stuff with their bags.

The idea that you could have some who can take their bags and some who can’t and that this would be acceptable to everyone is just not going to work. Combine this with the fact that a crisis alters people’s abilities. Some may be injured, some may be shocked. Then some poor crew member has to police the bs behaviour that would result.


In addition to the problem of slow retrieval by some causing a delay for everyone, we have congestion in the aisles from items much less important than people, additional trip hazards, and hazards to people and the slide itself on exiting.

I’ve been through training of smoke in aircraft, and it’s total chaos without adding things to trip over.

Airplanes contain a myriad of toxic-when-burned compounds, and death from smoke inhalation within the sealed tube of a fuselage is a matter of seconds.


There should be a switch in the cockpit that automatically locks all overhead bins if the pilots anticipate an evacuation. This information should be given to the passengers during the pre flight briefing.


Those many months and bad experiences won’t matter if you are dead.

And if it doesn’t look like a life-or-death situation, then you can come back later to retrieve the luggage. There is absolutely no reason to carry it during an emergency, period.


> I am not convinced about the wisdom of forbidding to take the hand luggage.

Famous last words. /s

Telemetry does not slow down the program. It is only one network access.

And so on, and so forth.


I initially assumed the title meant the location of your seat on the plane and thought:

oh boy, that's one more thing that (1) passengers will irrationally fear about and spread hearsay about "safest" seats on a plane and (2) airlines will try to charge a premium for those safest seats :)


Last I heard it was the back of the plane that was statistically safer. Most people still seem to want the front because it gets you off the plane faster and puts you at the front of the passport queue. Especially on larger planes going to places with lots of non-locals going through the slower manual channels.


Speak loudly to your travel companion during boarding: “Glad we got our seats far away from the crumple zone in the front.”


I once traveled with the basket ball team for my university, and the head coach was insistent on sitting in the very last row of the plane. When asked about it he said "I've never heard of a plane backing into a mountain."


That was one of the Jokes from David Gunson's "What goes up might come down" [1]; an after dinner speech given and recorded in the early 80's. It's 50 minutes long, which briefly takes you through his history as a fighter pilot, self employed civil servant doing ATC and then gives the listener some handy hints on how to fly, take-off and land a jumbo yourself (should you ever find yourself in that situation) as well as some musings on Concorde.

A truly hilarious and surprisingly educational listen, recommended to anyone who likes flying and Pythonesq humour. Stunningly quotable as well.

I caution that there are a couple of questionable and dated jokes made, but for early 1980's it's surprisingly PC.

[1] https://www.youtube.com/watch?v=nCA5qpBWDcI


They should simply add the (expensive) option to buy a parachute that you may take home if unused.


You need to be trained to use a parachute. You also can’t jump out at 35000ft doing nearly the speed of sound and expect to have a good time.


I'll take my chances


I wish they had modelled the effects of installing the passenger seats facing backwards. Passengers have no need to see forward in a plane, different from pilots, and in the event of sudden deceleration the seat would help cushion the impact, what I believe would probably improve safety in most survivable crash scenarios.


I think it would absolutely improve safety. Except for some very contrived scenarios, deceleration in a crash approaches infinity (mitigated only by the elasticity of the fuselage and whatever it impacts). Better to experience that spread out across a soft seat cushion than concentrated into an inelastic lap and shoulder belt.

Unfortunately, the psyche of the average passenger can't handle riding backwards. I've never understood it. Remove visual stimuli and it's impossible to tell the difference. Maybe we just need to close the window shades on takeoff and landing?


Many trains have backward facing seats. It's not common for people to have a problem sitting in them, certainly a minority. And train windows are usually several times larger than plane windows.


Belts are actually elastic. They just are not that easy to stretch, which is exactly what you want.


I get car sick almost immediately if I don't face forward.

Ditto amusement park rides that move backwards (eg The Mummy). This includes when there is no visual indicator (in the dark)


Wouldn't it make some people feel sick? Not sure if there's any science to back people preferring to sit forward facing in trains


A few seats could be left facing forward, for people who would feel sick, but backward facing probably should be default. It's hard to believe smashing your face against the hard back surface from the seat in front of you is better than being pushed hard against the soft cushion from your own seat. Also the load would be more evenly distributed across the whole body.


I thought about that, but then I realized that the acceleration is going to be (more or less) equal and opposite for take-off and landing, so it's more about which one you want first, no?


The angle of descent is of about 3 degrees, that's far less than the angle at which the aircraft is taking off. Thus the rear facing passengers would be facing down quite steeply on takeoff, and thus likely to vomit the airport lounge food they just had :)


Trains accelerate and decelerate relatively often compared to planes where you only really notice changes in velocity at take-off and landing so I don't think it would make a difference


Japanese limited express trains and the bullet train have very few stops (or none, depending), and the ride is very smooth.. still, my wife (Japanese) can't sit backwards-facing without getting sick. Not sure what causes this.


Tangentially related: The seats on Shinkansen trains can be rotated to adapt to the needs of the passengers.


Many US commuter-rail trains also have reversible seats. The train crew generally orient these to be forward-facing for the direction of travel, possibly excepting the first seat in a car.

(The trainsets reverse directions without being turned around themselves. Those using locomotives rather than electric traction operate in "pusher" mode for half their trips. There's an operator cab in the end car for such trips.)


They can be rotated, but that's supposed to be done by train personnel when changing directions. That's the primary purpose. The only time you're allowed to rotate them yourselves is when you're e.g. a group of four - then you can have two sets of seats face each other.


It would not surprise if there was something about human physiology that thinks it’s unnatural to go backwards. Our eyes are in front of our head for a reason.


I don't know for sure, but is very common to see parents carrying children facing backwards in their arms, while walking, with no ill effects. No big deal.


Sure, but there’s a speed limit to that, and you sort of trust the person holding you implicitly.

Not really applicable to an aircraft hurtling along at 300m/s


But you don't notice that speed.. (ref. Newton and Einstein and others). I agree with those saying it must be psychological.. well, mostly. Sometimes you do physically notice that you're facing backwards. At takeoff, for example. And, to some extent, landing. Maybe when banking too. I haven't tried, obviously (the backwards-facing unfolding seats for the crew would be the place to test this).


Military troop transports frequently utilise rear-facing seats, and I suspect there's enough incident data to arrive at useful conclusions.


I suspect recruits susceptible to motion sickness don’t make it through basic training


Or would be forced to walk ;-)

Fair point that the military can choose its subjects, or compel them.


There are some planes with a few backward facing seats. Takeoff is more comfortable in a forward facing seat


They had 17 test variants but they thought it was too much effort to try multiple times?

It sounds really interesting, but without multiple tries I’m not sure how much weight I can put on this.


Wouldn't it be easier that the whole part which holds the seats would be modular. So you get in your seat and the whole seat part with 300 or so seats is pushed into the plane on a rail. Fastened with whatever at X points and the plane is ready to go.

So in a case of accident it can be jettisoned from the main fuselage, and it would land with a parachute without anyone getting injured.


From the summary, it is unclear if this study takes into account human behavior vs a dummy when the hands are on top of the front seat back. While a dummy may not hold the front seat with a tighter grasp with its hands, a human during impact may or may not change the outcome through either pushing the front seat out or pulling it backwards which can directly alter the outcome of the study.


This reminds me of the “Plane Crash” documentary where a 727 was crashed into a desert in Mexico. Definitely worth a watch for any aviation enthusiasts: https://en.m.wikipedia.org/wiki/2012_Boeing_727_crash_experi...


In a crashing plane, the best position is in front of the plane. There, at least the drinks trolley comes by one more time.


"To reduce detrimental interaction between the occupant’s arms and the seatback, the current position was modified by placing the hands down by the lower legs instead of on the seat back. This alternate position was successful in significantly reducing head and neck injury risk for all of the seat back types evaluated."


I am done for in any case.

Current airplane seats are set up too closely to fit my femurs. There's simply not enough space for me to put my head down, independently of where my arms go ;(


Same, there's no way I can put my head down, in ordinary economy seats, and I'm only slightly above average tall.


Your head goes against the back of the seat in front of you then.


Casual readers will want page 3 for a description of the different positions and page 17 for a discussion of the results. The tldr is that the best seems to be: head against the seat in front of you, arms down by the lower legs.

The fact that any brace position won't help in a head on collision and the foolish inference that it is therefore at best pointless and at worst some kind of ghoulish conspiracy (to maintain dental records, to ensure quick deaths yada yada) is a real bugbear of mine. Same goes for the criticism of "hide under a table during a nuclear attack". With any catastrophe, there are unavoidable deaths from the initial impact and loads of avoidable deaths and injuries from falling debris, glass shards, smoke inhalation etc. These measures are about the latter.


I’m sure during history class we looked at an analysis of some kind around Japanese who survived the nuclear bombs. At a certain distance from the center being sat down below a window was enough to survive whereas stood up in the same location would be fatal. Said history class was 25 years ago though so might be in accurate or out of date.


There's also this:

> A fourth-grade teacher in Chelyabinsk, Yulia Karbysheva, was hailed as a hero after saving 44 children from imploding window glass cuts. Despite not knowing the origin of the intense flash of light, Karbysheva thought it prudent to take precautionary measures by ordering her students to stay away from the room's windows and to perform a duck and cover maneuver and then to leave the building. Karbysheva, who remained standing, was seriously lacerated when the blast arrived and window glass severed a tendon in one of her arms and left thigh; none of her students, whom she ordered to hide under their desks, suffered cuts. The teacher was taken to a hospital which received 112 people that day. The majority of the patients were suffering from cuts.

From https://en.wikipedia.org/wiki/Chelyabinsk_meteor


Speaking of bugbears. I have been fairly horrified by nuclear war and have read a ton of stuff about it.

If you aren't immediately killed by a fireball, or roasted by radiated heat, and are outside the "everything gets blown down" radius, it seems the major immediate danger is extreme winds from the blast. (Though radiated heat is also a line of sight effect)

So it absolutely makes sense that you'd want to be in a position that prevents all kinds of glass and debris impact, let alone getting thrown yourself.

My mental model is "instant tornado" and since I'm in the north, we all have basements to run to.


I love the ‘instant tornado’ image.


I heard a story about a guy, who was one of the few survivors in a crash. His explanation was that he had his waist belt very tight. On his way out he saw a lot of people with severe abdominal injuries, caused by being flung into the slack belt. Does this sound plausible at all?

EDIT: typo


It would depend on the mechanics of the crash, but sure. Safety belts are inelastic, so any shock and subsequent deceleration experienced by the body at the end of the belt's slack will be absorbed by tissue and skeleton.

This is also why climbers use "dynamic" (elastic) ropes (when climbing, not necessarily for rappelling). Even a very short fall on a static line could be fatal.


This is called "submarining" and it's a factor in seat shape design. It's also one of the reasons why car seatbelts have pretensioners.


This is extremely unlikely for several reasons.

1. There hasn't been a crash involving a commercial flight with few survivors in living memory. Either you get something like MH370 where everyone perishes or you get Asiana in SF which had three fatalities.

2. Absolutely baloney about the belt, the worst you can get is a bruise.


Confidently asserting that there hasn't been a crash involving a commercial flight with few survivors in living memory and your examples are all post-2010 flights is...certainly something. There are plenty of people much older than 20-30 years still kicking.

And you can get a hell of a lot more than a bruise from a seatbelt due to the magnitude of the forces involved in a plane crash, especially one that [allegedly] killed almost everyone else. Seat belt syndrome is a well-known thing.

The GP's story may or may not be true but your points for it being "extremely unlikely" don't hold water at all.


Summary of results?


The abstract is on the third page:

"In the event of an accident, one action that an occupant can take to contribute to their survival is to assume an appropriate “brace-for-impact” position. This is an action in which a person pre-positions their body against whatever they are most likely to be thrown against, significantly reducing injuries sustained. Occupants in the US Airways flight 1549 sustained shoulder injuries that they attributed to the brace position; therefore, the NTSB recommended that the position be re-evaluated. The Federal Aviation Administration investigated this by conducting a series of 17 sled impact tests, 15 with two rows of transport category forward facing passenger seats and two with a bulkhead configured to represent the types of seats currently in use. Head, neck, upper and lower leg injury risks were evaluated using an advanced test dummy and injury criteria from current FAA regulations, Federal Motor Vehicle Safety Standards, European auto safety regulations, and applicable research findings. The current brace position, head against the seat back with hands on top of the seat back, was only successful in reducing head injury risk for locked-out seat backs. However, for full break-over and energy absorbing seat backs, this position increased the severity of the head impact. There was, however, no evidence that the anthropomorphic test device interaction with any of the seatback types resulted in hyper- extension of the shoulder joint. Significant lower leg injury potential was not observed in this study, and therefore adopting lower leg injury criteria at this time does not appear to be a benefit. Even in the worst case test condition, the femur axial compressive force was below the regulatory limit, indicating that the femur compression criteria currently cited in FAA regulations is not likely to be exceeded in passenger seat dynamic qualification tests. To reduce detrimental interaction between the occupant’s arms and the seatback, the current position was modified by placing the hands down by the lower legs instead of on the seat back. This alternate position was successful in significantly reducing head and neck injury risk for all of the seat back types evaluated. This research has led to the determination that as seat technology has evolved, the most effective brace position has as well, and the current positions recommended in AC 121- 24B may need some adjustment to provide an equivalent level of safety for all passenger seat back types"




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