"Crash-worthy". How much should we weigh it when we consider our airplane requirements? You know, the structural 'passenger cage' that the tube and fabric planes had/have. Engines do quit for a variety of reasons. If you fly over rugged terrain or at night-or both, I would think this would be a higher consideration than for farm country day flights.
I would think (sorry, it sometimes can't be helped) that most BCPr's would put this as a priority, because when we take off, and, frequently, when we land, we are very dependent on the engine and prop working for us.

Maule, high wing pipers, Mooney, Found....... all have cages (Found cage-very impressive). I know there are more older planes, too. If an engine fails, and your on a spontaneous final in rough country......what would that cage be worth?

I owe my eldest sons continued existance (and his passengers) to a mild steel cage plus newly placed 4pt. seatbelts. It was an older Champ. Accident investigator indicated a C150 would have almost certainly been a double fatal......

I throw this out for consideration as something we should weigh. I fly a Cessna (NOT crash-worthy) as much or more than the cub, so.......I'm not on my high horse here, Just something that should be..........considered. Crash helmets have been discussed, and Nomex discussed. At Puyallup WA air fair they had a lot on survival after the crash. I searched BCP and didn't find this topic. I know, $$$$,$$$, & $$$$.

I guess I think surving the crash in good enough shape to be using that 406, or SPOT or whatever, Is pretty important, too.

I know I don't have to request comments from this crowd.

I think that the "G" load that is put on your body is the most concern. Does anybody know somone that has head restraint like in NASCAR.

Tim

i would say a 182-c is quite crash worthy if put down correctly...no airplane is gonna protect u much if you tumble
it and breech the fuel tanks. best to concentrate on flying it 'till it quits moving...!

An additional IMPORTANT factor is SLOWER stall speed/impact speed means less energy to be dissipated by the surrounding structure. I belive energy goes up by the square or exponentially (step in here engineers....) as the speed increases, so a little slower is a lot better (That much I know).

Cessnas do everything 'well' or better because they make some good choices. Not great at any one thing, but fly-wise solid plus performers in all categories. Crash-wise? Not. They are bent (angled) aluminium and corrigated Al and do not protect the occupants- along with low wing SE Pipers, and Beach and all the others built on that principle (very high % of recent aircraft manufactured).

Also if you have a wing root mounted shoulder harness (3 pt) that is Cessna standard, if you are going to dissapate energy by taking the wings off in a controlled crash, be sure to consider disconnecting the shoulder harness. It can be very hard on the neck (I would like that to be confirmed by an accident investigator, and not just rumor).

Ok so I am in a situation with an engine problem (not over I-80 in Nevada). Catastophic engine failure. What are the procedures beside best glide to the best place to set it down with in glide range.

I have a 182B with Bass harnesses. So I open the doore and set locks so it cannot close. The reason for this is to be able to open it after impact. I have been told that the body can take more "G"s foing forward than coming down on your but. In other words crash in the landing attitude not in a stall. I am sure that you should turn off the master and fuel valve.

Tim

Littlecub wrote:An additional IMPORTANT factor is SLOWER stall speed/impact speed means less energy to be dissipated by the surrounding structure. I belive energy goes up by the square or exponentially (step in here engineers....) as the speed increases, so a little slower is a lot better (That much I know).

Cessnas do everything 'well' or better because they make some good choices. Not great at any one thing, but fly-wise solid plus performers in all categories. Crash-wise? Not. They are bent (angled) aluminium and corrigated Al and do not protect the occupants- along with low wing SE Pipers, and Beach and all the others built on that principle (very high % of recent aircraft manufactured).

Also if you have a wing root mounted shoulder harness (3 pt) that is Cessna standard, if you are going to dissapate energy by taking the wings off in a controlled crash, be sure to consider disconnecting the shoulder harness. It can be very hard on the neck (I would like that to be confirmed by an accident investigator, and not just rumor).

I'm not an accident investigator, but I was once at the site of a Cherokee 140 crash. The trees took the wings off. I understand that the lap belt is attached to the spar running under the front seats. Cut the pilot in two when the wings left. Now, please understand that this accident was inevitably going to be fatal anyway. The airplane impacted in a steep, high speed dive. However, it was noteworthy that the pilot didn't survive until the final impact, he was gone when the wings first impacted the trees.

I owned a Cherokee 180 at the time and vowed to release my lap belt if I was ever in a position to make a forced landing where shedding the wings was a real possibility. I guess I determined I'd much rather go through the windshield in one piece.

Could the legs have been ripped of due to the fact that his body kept going after the plane stopped. Bones, tendons and tissue will only hold so long. That is why the rack was invented to get that much need information. I would rather be Water Boarded.

The more I think about it, I am starting to get concerned about my mtn bike and other stuff creushing me from behind. Oh and how about that tool box I carry.

Tim

People around here still haul water to their cisterns with tanks in the back of their pickups. Every once in a while I hear a story, could be a wives tale, about someone getting in a wreck and the water tank coming through the back of the cab because of the sudden velocity change and killing the driver. That's always in the back of my head and makes me think about everything that rides behind me.

Long ago, I read that the difference between a retract and fixed gear in a crash was that the fixed gear would be in one place while the retract would be spread out. While this may not really be true, it stuck with me. Since the amount of energy to be disapated is based on the square of the speed, slower is way the heck better.

When I purchased my Husky, I ordered the AmSafe airbag system as well. Figured that if I'm ever over enemy territory and the engine quits, I'd be kicking myself for not getting the bags all the way down final to the pine trees.

bumper

Exactly. I have no idea where you got the notion that a Maule/high wing Piper, etc are any more "crashworthy" than a Cessna airplane.

Monocoque airframes, such as the Cessna designs, can be just as tough in a crash sequence as any aircraft with what you refer to as a "crash cage". Actually, those aren't "crash cages" at all--just a different way to provide structural rigidity for an airplane.

The key to survival in an airplane accident is to fly the airplane until it stops, and arrive at the slowest possible speed. Speed at arrival, and therefore energy that must be dissipated is the huge player in this field, and an airplane that stalls slowest will do best, ASSUMING the pilot actually slows it down prior to touchdown.

There are a lot of other variables in this regard, not the least of which is the kind of terrain you're landing in.

Good shoulder harnesses, good seat belts (note that the "high wing Piper" aircraft had their seat belts attached to the SEAT FRAME, by the way-a notably bad idea) and landing as slow as possible, those are the keys.

And, I cannot believe anyone would even suggest removal of seat belts prior to touchdown in an off airport landing.

Good grief!!

Where do you guys come up with some of this stuff???? Too much listening to Bill Cosby's old recordings??

MTV

Well, just a few thoughts on this nasty topic,
My lap belts are bolted to the lower cross member of the cabin, not the seat frame and the shoulder harness 4 point is bolted to the tubing in the top of the cocpit and not to the wing roots.

The old Stinson has a pretty good looking cage to it, I have had mine a nekked as a jaybird and can attest to that but it is still mighty puny compared to a decent roll cage on a jeep or something.

A set of floats will crumple and absorb a tremendous amount of force during impact,

A very very rough landing in any kind of terrain is far better than the best crash on your nose or worse yet on a wing tip, as has been said fly the plane all the way down.

Last but not least nobody can keep a plane in the air by will power, when that sucker is done flying it is going to fall. This creates very bad results such as the aforementioned lawn dart or cartwheel landings.

If there is nothing you can do to get more power, ie total engine failure pick your spot and land, don't wait till she quits flying and falls.

Now, I have not ever crashed a plane nor even torn one up badly so these opinions of mine are just like A holes, everybodies got one and most of em stink.

Back in my Civil Air Patrol days, we were first on scene at a cessna 140 crash. It went down in a sudden wind storm, and was maybe twenty feet from the pilot's airstrip next to his cornfield. The aircraft was in relatively good shape, little damage to the fuselage and some wing damage. Both occupants were killed, however, by blunt force trauma to the head, one when his head hit the glareshield, the other when somehow his upper body hit the door with enough force to take the pilot's side door off and his head hit the left main wheel(probably more internal injuries as well, but I'm not a doctor). Not too sure about the crashworthiness, but given what some people are considering crashworthiness in strength of the area surrounding the occupants, this one seemed "crashworthy." Even so, two fatalities...

I will second the notion that the steel tube frames use in most fabric covered aircraft (and a few metal covered ones as well) are not a "crash cage." Back in the 70s, I used to race stock cars. If this period "." is the diameter of the structural tubes in an aircraft, this "O" is the diameter of the tubing used in our car's roll cage. The cage was very effective (I once went over the wall and into the parking lot - walked away with a few sore muscles) but much stronger than the aircraft variety.

I used to build stock cars and the roll cage inside those cars was built from boiler tubing..very strong for the weight. No matter how bad the crash was the cage was never compromised. The worst injury the driver ever had was a broken thumb. I've been there and done that in a cub...folded one wing back and highly damaged the other. The impact broke the plane's back. Just lap belts were in use and man do those belts stretch! I hit my head on the cross cable up behind the front seat. The only things that were intact were the cabin and the landing gear. I stepped out of the plane with only a small scratch on the forehead and some pulled muscles. I have seen wrecks that were not this bad and the people did not survive. When we rebuilt the plane we put harnesses in for the next time. It's been said before and I'll say it again.....fly the damned thing as far into the crash as you can...it may save your life! HC

People are killed in crashes from trauma (non-fire) because their bodies are also traveling the same speed as the aircraft. Whether or not the cockpit is compromised from the crash usually doesn't have as much effect on survivability as the considerations that keep the occupants from slamming their delicate bodies into the control column/panel/door post/cross brace/etc. Getting neck whipped or having your head bounced off the door in a side-slipping impact are much more likely to kill you than loss of cabin structural integrity. After all, you can die from hitting your head on a groomed beginner ski slope.

I think that airbag system that Bumper mentioned has some real merits. Either that or wear a helmet and some body armor. Even then, the forces we're dealing with at that speed are so great (especially when assisted by the acceleration of gravity) that really no pilot or passenger stands a chance unless impact force is mitigated by piloting the craft as slow as possible and as close as possible to the ground, as mentioned above.

We all play that scenario in our minds, probably often. I just find it disturbing that many accidents that are simple noseovers are so injurious or fatal.

If you're worried about surviving an accident, you should fly the safest airplane in the world, a Piper J3 Cub-- it can just barely go fast enough to kill you.

1SeventyZ wrote:People are killed in crashes from trauma (non-fire) because their bodies are also traveling the same speed as the aircraft. Whether or not the cockpit is compromised from the crash usually doesn't have as much effect on survivability as the considerations that keep the occupants from slamming their delicate bodies into the control column/panel/door post/cross brace/etc. Getting neck whipped or having your head bounced off the door in a side-slipping impact are much more likely to kill you than loss of cabin structural integrity. After all, you can die from hitting your head on a groomed beginner ski slope.

Don't forget what's on the inside. (of your skin) You can be just fine on the surface, with no broken bones or cuts, but if you rearrange your thoracic organs or move your brain inside its container, no go no mo.

As someone noted above, kinetic energy increases with the square of the speed: E = 1/2 * m * v^2 ... where m is mass and v is velocity.
However, you don't want to look at the energy of the aircraft to ascertain the survivability of a crash - on every landing we transfer an awful lot of energy into the brakes, air etc but because we do it in a controlled fashion over a period of time we hope to survive most landings.
What kills you, aside from mechanical injury (the toolbox in the head scenario), is the acceleration.

Generally people are fine up to about 20G (sustained).
Past that you can be injured, or killed if you experience very high g-loads, especially if the period of acceleration lasts too long.
This is a useful formula:

Peak G = v^2/(gs)

where v is velocity, g is acceleration due to gravity (9.8m/s) and s is the distance used to accelerate from v to zero velocity. (decelerate if you prefer)
The average G-force over the duration of the crash is typically about half of the peak.

Some back of the envelope calculations:

Crashing from 60kts, into a tree and stopping in 1 meter (3 ft) ...

60 kts = 30m/s

Peak G = 30^2/(10 * 1) = 900/10 = 90g
Average G = 45g

... probably won't walk away from that one regardless of the harness and roll cage.

Lets say we crash into some small trees and stop over 10 meters (30 feet) ....

Peak G = 30^2/(10 * 10) = 900/100 = 9g
Average G = 4.5g

That should certainly be survivable provided you are properly restrained and nothing hits/punctures you.

Reducing speed to 40kts, the peak-G forces would be 40g and 4g respectively.

So, when you look at a Cessna airframe which would probably crumple in a crash you should not assume that it's less safe - it may actually be safer by increasing the distance over which your body is decelerated. This is why they build crumple zones into cars - weaker spots that actually make the structure safer.

A combination of reducing speed and increasing the stopping distance should lead to the best possible outcome.

Interesting paper on crash survivability:
http://ftp.rta.nato.int/public//PubFull ... 113-06.pdf

Excellent explanation JimmyMeBoy. So one would conclude that when one is about to crash one should try and pick spots that will allow one to skid along some distance as opposed to spots that will bring one to a sudden stop.

Strider,

No joke, actually. In 1984 at the Reno Air Races, a F-1 pilot rounding the scatter pylon lost it very close to the ground, knife edge and going like stink. He skidded out across the desert, leaving an impressive plume of dust as he went.

The helicopter with EMTs took off and flew to the crash site. We all expected to hear of a fatality. The wait was interminable, but the announcer finally came on and announced that the pilot of the F-1 was uninjured, and was walking back to the airport, because he refused to fly in helicopters--they are dangerous... A couple of EMT's walked back with him.

He hit the ground a glancing blow, and ground that little airplane down to nothing, gradually expending energy. Skidded a good half mile.

MTV