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20+ G Deceleration...Survivable?

TXFlyGuy

Well Known Member
I just read a full accident report on an experimental aircraft that was involved in a fatal crash. There were too many contributing factors to the fatality to list here (read the report), but the NZ CAA determined the vertical impact G load was near 20 G's. And the horizontal G load was over 7 G's.

Of interest was the fact that the restraint system was attached to the seat frame, which was welded to the stringers (aircraft fuselage frame). The welds failed on the left hand side. This allowed the pilot to be flailed into the glare shield and instrument panel. Instant death. He was 80 years old, not that that had any impact on the event.

It is my thinking that the 20 G's were an overall contributing factor to the welds failing.

How many 20+ G impacts by RV aircraft have been survived by the pilot? Are 20 G crashes very common, and are they normally easily survived by pilot/passengers?

While this particular fatal crash did not involve an RV, it makes for educational reading. The report is well written by the New Zealand CAA.

Here is a link: https://www.caa.govt.nz/assets/legac...-SMF-Fatal.pdf

I'm not seeking a critique of the accident aircraft (beat to death already), rather information on harness systems.

And, how many here have a restraint system that would easily withstand a 20+ G load, and save your butt? Probably everyone on this forum.

I just ordered a custom harness from Crow Enterprises. In addition, we are re-making our seat cushions, utilizing special G load absorbing memory foam. You know, that Green, Blue and Pink stuff!
 
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24G Impact

There are more than a few former Grumman pilots who are now Vans owners. This is a youtube video from Roscoe that walks you through *his* 24.5 G forced landing of a Grumman AA1B this past year up in the Cincinnati area. Definitely survivable.

https://www.youtube.com/watch?v=pQktd6vJIwo
 
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Not the best restraints

Dang! Pretty amazing. So, the restraint system failed? The pilot hit his head on the windscreen (3 times?).

The AA1 series of aircraft didn't have the 4 point restraints, just 3 point. It's very easy to slide out sideways from the single shoulder harness. I suspect that played a part in this.
 
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60 mph - 6 ft stopping distance - 20g

...
How many 20+ G impacts by RV aircraft have been survived by the pilot? Are 20 G crashes very common, and are they normally easily survived by pilot/passengers? ...
Stopping in 6 feet from 60 mph will give you a nice 20g experience if the online calculator here is accurate - too lazy to do the math myself.

https://www.omnicalculator.com/physics/car-crash-force

I'm sure many off-field landings are less than 60 mph, but it seemed a nice round number.
 
Try -55 G or +83 G

Col John Stap really laid it on the line with his rocket sled deceleration rides in May of 1958. I doubt there will be many volunteers try to even match what he survived at -55G.
Capt. Eli Beeding had a bit tougher experience at +83 G but reportedly was back at work in a few days.

https://youtu.be/siau78EFLgc
 
I can’t remember the approximate ejection seat G, but I believe it is in excess of 20g. We can take a pretty large spike, but for only a brief amount of time. It is a function of g and time that kills. That being said, wreckage is different than a pure accel/deccel.

The wiki link https://en.m.wikipedia.org/wiki/G-force has some good info on human tolerance.
 
Well, pardon me for not being explicit.

How many "crash events" that are 20+ G's prove to be survivable? Of interest is the RV aircraft, and in general other experimental types. And the associated restraint systems.

It is understood that we can survive 35, 40, or more G's in an environmentally controlled deceleration.
 
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The airframe design is rather important. For more insight, download the "Small Airplane Crashworthiness Design Guide," a free pdf. You'll have to search for it but it's an easy search.

One thing that does sometimes happen, at least in the older RVs, is that the cockpit sides buckle inward, injuring the occupants, and then rebounding when the crash loads end. Little damage visible afterwards unless you know what to look for. And that's a relatively common phenomena in crashes.

Dave
 
Look at the last pic in the CAA report, of an intact seat back. I'm not an engineer, though I've sought their advice when building a motor mount. Perhaps an actual engineer will weigh in on the subject, but when considering loads imposed by the shoulder harness in a crash, it looks like just about everything is wrong in that photo, even with the attachment at the 'recommended' location. Primary load in the middle of a beam (no triangulation), butt welds loaded in tension at one point, in peel in another, etc.

The report says that impact was at 70 kts (around 80 mph) and that an eyewitness (who I'm guessing was a pilot) said that the plan impacted 'nose low'. Sounds like a perfect storm.

Charlie
 
It's not all about the total G load, the rate of the acceleration change and the duration of the load also play into it. Sprint car drivers have had survivable incidents where the max G was measured up in the 50's, but not for a sustained interval.

We've all probably seen the diagram where survivability is plotted against velocity at impact. The two best ways to reduce your risk is to fly an airplane with a slow stall speed (50knots or so), and don't stall from too far up. Seatbelts don't do much good if the points you attach them to are already broken or deformed when they load up.
 
Oh, no!

"...The two best ways to reduce your risk is to fly an airplane with a slow stall speed (50knots or so), and don't stall from too far up..."

You can die in a 50 knot crash just as easily as in a 70 knot crash if the harness or structure is improperly designed or executed.

I assume you are saying that you shouldn't stall too far up if you are crash landing...I think I would rather fly the airplane as far into the crash as possible.

Case in point, years ago, one of our training aircraft, C-172RG, had a catastrophic engine failure (long story, no one's fault). The pilot, a recently minted Private with 110 hours TT, Put the airplane in a clearcut logging area. He flew it right up to ground contact. The airplane was totaled...he and his passenger walked away from the crash with minor cuts and bruises...

Never give up, never surrender...
 
Large Drift

This is a long way from the question and intent of the Op in this thread,

However, The first thing that went through my mind when reading the report, was how easy it is to tie an appropriate tension scale or load cell or what ever you have available to the tail wheel while pointing the nose into the wind and doing an extensive ground run to measure the power and thrust developed after an engine instal and or after changes have been made. In the air is no place to find out you don't have enough power.

A 260 HP IO 540 will make around 1000 Lbs of static thrust.,

Cessna 180 with 230hp Continental O-470-L engine.

Propeller Diameter RPM Pounds of Pull
2-Blade McCauley 2A34C203/90DC-8 82" 2600 765 pounds
2-Blade McCauley 2A34C203/90DC-2 88" 2600 870 pounds
3-Blade Hartzell PHC-C3YF-1RF/F8068 82" 2600 900 pounds
3-Blade Hartzell PHC-C3YF-1RF/F8068+2 84" 2600 935 pounds

Cessna 182 with Continental O-550 285 HP engine

Propeller Diameter RPM Pounds of Pull
3-Blade Hartzell PHC-C3YF-1RF/F8068+2 84" 2700 1125 pounds
3-Blade McCauley D3A34C401/90DFA-4 86" 2700 1140 pounds


A 200HP 360 makes close to 680 lbs thrust with a well matched 2 blade.

Even the O-320 E2D with a 2 blade FP McCauley 7553 in a C-172 will make 215 KG =473 LBS
as measured here: https://download.atlantis-press.com/article/2629.pdf

Most builders should know what a given airframe needs for safe flight, power wise. If not find out and even after your fuel flow tests have proven adequate make sure it does produce and will maintain adequate thrust.
 
You won't get any disagreement from me Bob. My only point was that if I'm going to be able to pick my crash configuration, it's going to be at the slowest possible speed to minimize the need to dissipate kinetic energy on impact. Thereby reducing the load on the belts, the airframe, and my body. That speed will be dictated largely by the stall speed. RV's have a low stall speed. Lancairs, clipped wing/overpowered/heavy aircraft, lot's of canards (foregive me, landing speed) - not so much.

"...The two best ways to reduce your risk is to fly an airplane with a slow stall speed (50knots or so), and don't stall from too far up..."

You can die in a 50 knot crash just as easily as in a 70 knot crash if the harness or structure is improperly designed or executed.

I assume you are saying that you shouldn't stall too far up if you are crash landing...I think I would rather fly the airplane as far into the crash as possible.

Case in point, years ago, one of our training aircraft, C-172RG, had a catastrophic engine failure (long story, no one's fault). The pilot, a recently minted Private with 110 hours TT, Put the airplane in a clearcut logging area. He flew it right up to ground contact. The airplane was totaled...he and his passenger walked away from the crash with minor cuts and bruises...

Never give up, never surrender...
 
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There is more info on the subject plane (not an RV), but I think the whole report applies to all experimental aircraft, especially in the "do not do this" department.

The pilot relocated the seats/seat frame aft of the factory location. We are very suspicious of the welds made at the frame/stringer, due to them snapping off like they did.

In addition, the pilot had a habit of space shuttle like climbouts after takeoff, at relatively low airspeed.

When the engine quit, or was accidentally shut down, the right wing dropped and the plane went into a descent. I would suspect this was an incipient stall/spin situation, but not enough altitude to get fully developed.

The impact must have been rather flat, coming almost straight down.

Out of ideas, out of airspeed, and out of altitude...
 
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The airframe design is rather important. For more insight, download the "Small Airplane Crashworthiness Design Guide," a free pdf. You'll have to search for it but it's an easy search.

One thing that does sometimes happen, at least in the older RVs, is that the cockpit sides buckle inward, injuring the occupants, and then rebounding when the crash loads end. Little damage visible afterwards unless you know what to look for. And that's a relatively common phenomena in crashes.

Dave
You do want to have some give in the belts to slow deceleration, but not so much as to allow occupants to impact the instrument panel/glareshield. The way the shoulder harness anchor points are set up in, say, a -7 or -9, I wonder if in a purely frontal impact, the fuselage sides would buckle inward from the forces? It could be a good thing, in moderation.

We should all strive for a purely frontal impact (at worst) in an off-field landing, if we're unlucky enough to find ourselves in that situation. Fly it all the way into the crash!
 
Probably should see what the experts say

There are any number of references that can be found,... the one below gives several values, with the important takeaway is that you can handle about twice as much fore and aft deceleration /g than you can vertical. I.e. 45g vs 20g

So,...remember as you PRACTICE engine out scenario,...and as you choose / install seats and seatbelt...Both vertical and forward speed are important,....

https://apps.dtic.mil/dtic/tr/fulltext/u2/a446339.pdf


Aside,...for us older folks,..you may remember when it became a thing to drive cars with your seat reclined way back,... when that happened there was a rise in deaths from ?survivable? accidents.....
guess what,.... too much relative vertical on the body
 
You do want to have some give in the belts to slow deceleration, but not so much as to allow occupants to impact the instrument panel/glareshield. The way the shoulder harness anchor points are set up in, say, a -7 or -9, I wonder if in a purely frontal impact, the fuselage sides would buckle inward from the forces? It could be a good thing, in moderation.

We should all strive for a purely frontal impact (at worst) in an off-field landing, if we're unlucky enough to find ourselves in that situation. Fly it all the way into the crash!

I see you like Bob Hoover too.

The video posted here, and the NZ accident, show two planes that had a high vertical G load.
That happens when you are in, or near a stall, coming down like a runaway elevator. And not in control of the plane.

Yes, you are correct in stating a frontal impact would be better. As long as you are still flying the plane. For sure better than coming down at 60 mph, and stopping in .1 seconds.
 
However, The first thing that went through my mind when reading the report, was how easy it is to tie an appropriate tension scale or load cell or what ever you have available to the tail wheel while pointing the nose into the wind and doing an extensive ground run to measure the power and thrust developed after an engine instal and or after changes have been made. In the air is no place to find out you don't have enough power.

Isn't there a thread here somewhere wherein some guys did exactly this, and damaged their aircraft by doing so? Bent the fuselage/bulkheads in the aft area, IIRC.
 
......One thing that does sometimes happen, at least in the older RVs, is that the cockpit sides buckle inward, injuring the occupants, and then rebounding when the crash loads end. .....

Intuitively you'd think the opposite would occur: in a frontal collision, the firewall moves aft together with connected longerons and the deceleration loads from the shoulder belt cable anchors pulling the aft part of the fuselage forward, together with the natural outward bow of the longerons, would cause the cockpit sidewalls to splay outwards. I'd expect that the seat back support tying the sidewalls together would help in that respect, at least until the rivets shear off.

What would cause the sidewalls to buckle inward instead?
 
Maybe I missed it, but is there a data base showing RV crashes, with the G loads experienced, and the impact on the pilot/passengers? Fatal/non-fatal?

Surely with 10,000 RV's out there, a good data base would be readily available showing every detail on this?
 
Isn't there a thread here somewhere wherein some guys did exactly this, and damaged their aircraft by doing so? Bent the fuselage/bulkheads in the aft area, IIRC.

HASI posted June 20, 2017
"Static thrust measured on my RV-7A with XIO 360-M1B and Hartzell 74" prop was 2974N @ QFE 957hPa and 16 deg. It was measured with load cell and plane anchored by Honda Civic, just after the governer limited RPM to 2700. (See Youtube: RV-7A thrust measurement)
Note: in Switzerland every Homebuilt has to be subjected to thrust measurement and it is usually done by EAS.[/list]"

"2974N = 679lbs = ~ 300 kg
1kg=9.81N"

I have watched a 6 and an 8 tested with no adverse effects.

I am sure with no engine running , if you took a chain, and tied that to something solid, just rolling any AC to a jerk stop (like a dog hitting the end of his leash) would destroy almost any airframe. But the idea is to pull gently not to jerk or shock. Should never use a chain.

Here is a TDI VW in a C172 pulling about 300 to 320 KG in Finland. https://youtu.be/gLmgKILUs4s

Here is an IO 720 with sling straps from the mains running back over the H stab to a single anchor point. Not Kevins first rodeo. https://youtu.be/PTzMcYs2m3g?t=43

Slings or ropes and some common sense in rigging should prevent disaster.

If somebody has had a bad experience it would be good to read the details. Remember the 8 that some guy ended with the wrecking claw to rid himself of any future liability? If ever there is a next time, it would be interesting to tie a 4000 lb load cell on a sling behind the tail wheel and anchor the motor mount with slings to a large frame and see what deforms first and at what tensile load.
 
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Just heard back from the Grumman pilots...

That crash with the 24+ G's? It was almost all vertical, with little horizontal G load.

That tells you a lot. Remember what Bob Hoover said...
 
Take away from racing Gs

So in reading this thread it reminded me of some of the bad race car crashes and what kind of restraints they may utilize. In this crash you can see Kenny Breck survive a 214G crash. Definitely had lots of broken bones but in keeping with the thread speaks to the harness systems ability to keep the driver put and let the cage take as much of the force as possible.

https://youtu.be/Hy8fgGiI1WA
 
Just heard back from the Grumman pilots...

That crash with the 24+ G's? It was almost all vertical, with little horizontal G load.

That tells you a lot. Remember what Bob Hoover said...

NASA did a lot of crash tests for GA in the '75-'80 time period. All posted. I remember one of the conclusions was that the vertical human chassis loading was the worst case and NASA pushed to get seats redesigned for that. Oregon Aero does testing for vertical impacts as many of their cushions are in military applications.

We could speculate on what specific impact in an RV might reduce the vertical.
 
So in reading this thread it reminded me of some of the bad race car crashes and what kind of restraints they may utilize. In this crash you can see Kenny Breck survive a 214G crash. Definitely had lots of broken bones but in keeping with the thread speaks to the harness systems ability to keep the driver put and let the cage take as much of the force as possible.

https://youtu.be/Hy8fgGiI1WA

Just read some of the comments on this. It appears that the fence actually absorbed a huge part of that total G load, saving the driver.

Doubt if any aircraft (certified/experimental) would do as well.
 
....What would cause the sidewalls to buckle inward instead?

Probably any sort of sideward g load, causing the tail to try to bend sidways. But often in a crash, the results are so nonlinear and large-deflection, that things happen which can't be assessed without either testing or expensive computer-aided analysis.

Dave
 
HASI posted June 20, 2017
"Static thrust measured on my RV-7A with XIO 360-M1B and Hartzell 74" prop was 2974N @ QFE 957hPa and 16 deg. It was measured with load cell and plane anchored by Honda Civic, just after the governer limited RPM to 2700. (See Youtube: RV-7A thrust measurement)
Note: in Switzerland every Homebuilt has to be subjected to thrust measurement and it is usually done by EAS.[/list]"

"2974N = 679lbs = ~ 300 kg
1kg=9.81N"

I have watched a 6 and an 8 tested with no adverse effects.

I am sure with no engine running , if you took a chain, and tied that to something solid, just rolling any AC to a jerk stop (like a dog hitting the end of his leash) would destroy almost any airframe. But the idea is to pull gently not to jerk or shock. Should never use a chain.

Here is a TDI VW in a C172 pulling about 300 to 320 KG in Finland. https://youtu.be/gLmgKILUs4s

Here is an IO 720 with sling straps from the mains running back over the H stab to a single anchor point. Not Kevins first rodeo. https://youtu.be/PTzMcYs2m3g?t=43

Slings or ropes and some common sense in rigging should prevent disaster.

If somebody has had a bad experience it would be good to read the details. Remember the 8 that some guy ended with the wrecking claw to rid himself of any future liability? If ever there is a next time, it would be interesting to tie a 4000 lb load cell on a sling behind the tail wheel and anchor the motor mount with slings to a large frame and see what deforms first and at what tensile load.

Well, I'm not in Switzerland, so that doesn't really matter to me. Do whatever you want, it's your airplane.
 
So, I guess there is no info on RV crashes, resulting G loads, restraint systems, frame distortion/torquing, pilot/passenger injury, fatal/non-fatal?
 
G-loads

So, I guess there is no info on RV crashes, resulting G loads, restraint systems, frame distortion/torquing, pilot/passenger injury, fatal/non-fatal?
I've read a lot of crash reports and don't recall too many that include information about estimated G loads that the aircraft sustained. Sometimes if there is a G-meter they include that info. Certainly there is information about fatalities, and sometimes there are indications of cause of death that might include information that you could use to deduce that it was caused by a high-g vertical impact.

It seems like the analysis you are looking for is still a green-field opportunity for a curious mind to develop.
 
I've read a lot of crash reports and don't recall too many that include information about estimated G loads that the aircraft sustained. Sometimes if there is a G-meter they include that info. Certainly there is information about fatalities, and sometimes there are indications of cause of death that might include information that you could use to deduce that it was caused by a high-g vertical impact.

It seems like the analysis you are looking for is still a green-field opportunity for a curious mind to develop.

Just figured with a data base of 10,000 airplanes, someone would have already ran the numbers on it, with full analysis.
 
All well and good but survivability is increased by more attention to restraints.

I recall a 78 yr old lady who expired in a relatively low speed auto accident because of Atherosclerosis. The "hardened" Aorta didn't tolerate the movement of the heart due to deceleration.

I've contemplated a "chest panel" incorporated into the shoulder straps to stop a phenomena I recall termed "bird chesting" (can't find it on web search) but it relates to the rib cage "extruding" through the shoulder straps - permitting more displacement of the heart.

Having said that, I now believe I've seen the accessory by some mfg's.

FWIW
 
All well and good but survivability is increased by more attention to restraints.

I recall a 78 yr old lady who expired in a relatively low speed auto accident because of Atherosclerosis. The "hardened" Aorta didn't tolerate the movement of the heart due to deceleration.

I've contemplated a "chest panel" incorporated into the shoulder straps to stop a phenomena I recall termed "bird chesting" (can't find it on web search) but it relates to the rib cage "extruding" through the shoulder straps - permitting more displacement of the heart.

Having said that, I now believe I've seen the accessory by some mfg's.

FWIW

That is interesting, for sure. As this may relate to the original post/subject crash, there is a very high probability that the 80 year old pilot in question, may not have survived under any circumstances. That near 20 G vertical impact (stalled/incipient spin) would probably have done him in.
 
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How would anyone know what the G was in a given crash other than some rough estimates based on an analysis of the wreckage, which is very hard to do when the airplane is destroyed? Peak G would be for a very short duration and the update rate of an EFIS, if it was recording, may well not catch it. You need 20hz or more. The black boxes in airliners only have 8hz and that won't catch the peaks - believe me we've tried for hard landings among other things. So getting back to the OP I don't know how you would answer that question.
 
How would anyone know what the G was in a given crash other than some rough estimates based on an analysis of the wreckage, which is very hard to do when the airplane is destroyed? Peak G would be for a very short duration and the update rate of an EFIS, if it was recording, may well not catch it. You need 20hz or more. The black boxes in airliners only have 8hz and that won't catch the peaks - believe me we've tried for hard landings among other things. So getting back to the OP I don't know how you would answer that question.

This makes sense. But, I thought it was a fairly simple math problem, time/distance/speed. On second thought, this would require pure guesses on part of the investigators, except for distance traveled. Unless a cockpit device (as you mentioned) could accurately capture that info.

I think current Boeing aircraft are very sophisticated in their ability to capture this data.
 
I suspect that you're getting way too wrapped up in that one '20g' word in the report. The seat back was torn loose at the top, and the instrument panel was caved in. Unless the autopsy said he died of spinal compression, I think you're looking in the wrong place for cause.

Beyond that, do you know how 'vertical' and 'horizontal' are defined in the report? Meaning, are they defined relative to the plane itself, or the earth. The 20Gs could be vertical to the earth, and a 45* angle relative to the plane (nose down, moving both down and forward), meaning a total of *much* more than 6-8 Gs forward on the pilot himself.
 
I suspect that you're getting way too wrapped up in that one '20g' word in the report. The seat back was torn loose at the top, and the instrument panel was caved in. Unless the autopsy said he died of spinal compression, I think you're looking in the wrong place for cause.

Beyond that, do you know how 'vertical' and 'horizontal' are defined in the report? Meaning, are they defined relative to the plane itself, or the earth. The 20Gs could be vertical to the earth, and a 45* angle relative to the plane (nose down, moving both down and forward), meaning a total of *much* more than 6-8 Gs forward on the pilot himself.

Good points. You're questions concerning how the loads were defined makes sense.
My suspicion is along those lines, in that the horizontal forces with vectoring factored in were far beyond the 7.3 G's listed by the CAA.

The report stated he died from head trauma, due to the impact of the glare shield. At 80, he may have been dead already, from the massive vertical G load. There was not one drop of blood that I could see anywhere, on the panel, or the glare shield.
In a similar Kitfox accident, where the pilot impacted everything, there was blood everywhere. Yes, you could see it on the almost black instrument panel. Head wounds are notorious for profuse bleeding, even minor ones. Dead men don't bleed.

Here is what I just received via email from the NZ CAA:

One aspect we don’t know in this accident, is whether or not the pilot actually had the shoulder harness tightened when he took off. If he had some slack in the harness when the aircraft struck the ground, the shock loading on the harness could have contributed to overloading the seat back frame.
 
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Survivable G loads

Some years back I worked on a research program for a pilot ejection system that would potentially be used for a supersonic ejection. The human factors guys provided numbers for ejection forces. The seat had a rocket that produced 10,000 lb of thrust for 5 seconds ( a controlled explosion). The challenge was to be able to control the attitude of the seat to keep it straight during the decelleration. The control system needed to be able to pitch the seat to the required pith up angle and keep it straight with no yaw. The design numbers were 28 G and no more than 5 degrees of yaw. Larger yaw angles would likely result in serious internal organ damage. Working through the numbers brought the realization that small changes in pitch and yaw would have very large delta G numbers attached much the same as a car or airplane accident injury results show. Commercial airplane internal components are designed and certified to withstand 16 G crash loads. Beyond that and the results are what they are - its all serendipity. Some accident victims will survive a described unsurvivable accident and others will be killed or very seriously injured in an otherwise survivable accident - just the luck of the draw. Far better to concentrate ones efforts in not getting into the accident situation in the first place in my view.
KT
 
Some accident victims will survive a described unsurvivable accident and others will be killed or very seriously injured in an otherwise survivable accident - just the luck of the draw. Far better to concentrate ones efforts in not getting into the accident situation in the first place in my view.
KT

I agree. In the reference case, even a helmet would not have helped. It appears the deceased may have succumbed to other impact injuries which effectively stopped his heart immediately.

Many of us suspect the victim's age played a role, both in being able to survive the event, and in the reaction time when confronted with the initial emergency.

I have the coroner's report. If anyone wants detailed info, please PM me. This is not to be made public, however. I only offer it as education as to what can and will happen in violent G impacts.
 
G Whiz...

How many 20+ G impacts by RV aircraft have been survived by the pilot? Are 20 G crashes very common, and are they normally easily survived by pilot/passengers?

Several years ago an RV4 was returning from Sun N Fun in FL to TX. Descending for a fuel stop in MS, the pilot became disoriented in marginal VFR, performing a inadvertent very low altitude Split-S maneuver and impacting trees and eventually terra firma. Amazingly, He survived. The NTSB report estimated the G force at impact in excess of 30G's. His story of waking up in the RV4 wreckage was sobering. One thing he mentioned was his 5 point harness breaking which later was determined to have functioned to and failed well in excess of design limits.
One of my F16 Bros survived a ground impact during a night low-level NVG training mission, ejecting at 500+Knots after impacting terrain, sustaining a estimated 15G vertical force followed by the 20+G ejection, avoiding high speed flailing injuries post-ejection and performing a night parachute landing fall (PLF) in mountainous terrain.
He was sore, his neck and spine may never be the same, but He walked away.

Both incidents have one thing in common, a gradual or steady G-onset deceleration rate rather than a sudden impact. The old adage about parachuting that "It's not the fall that kills you, it's the sudden stop" holds some truth.
Have a plan..

V/R
Smokey

The U.S. Army UH-60A, Black Hawk, helicopter is the first helicopter designed and built to modem crashworthiness standards. During the design of the Black Hawk, all common injury mechanisms were considered, and significant attempts were made to eliminate foreseeable injury hazards. Most important, the aircraft was designed to withstand an 11.6 m/s (38 ft/s) vertical impact without acceleration injury to the occupants or collapse of structure or high mass items into occupied space.
 
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And it has been pointed out to me that the history of engine failure related takeoff accidents is not pretty.

Many times the aircraft is stalled out at 30-50' AGL, resulting in a very hard impact. And serious injury, or fatality.

As pilots we need to always lower the nose, maintain min flying speed, and fly the plane all the way through the crash.

Human nature being what it is, many pilots try to stretch the glide, thinking they can make it...and they don't.
 
Turn of events...

And it has been pointed out to me that the history of engine failure related takeoff accidents is not pretty.

Many times the aircraft is stalled out at 30-50' AGL, resulting in a very hard impact. And serious injury, or fatality.

As pilots we need to always lower the nose, maintain min flying speed, and fly the plane all the way through the crash.

Human nature being what it is, many pilots try to stretch the glide, thinking they can make it...and they don't.

Actually, attempting to turn back is the primary killer on T/O engine failures (according to the FAA Safety Magazine) which is causal to the high descent rate, stall/spin etc.
My Dad, a 50+year CFI survived a catastrophic engine failure on takeoff at 200' in a Cessna 140 with a student. He performed basically a controlled crash in a subdivision cul-de-sac with minor injuries to himself and the student. Key word: survived.
The NTSB report called his landing an "unsurvivable scenario" due to terrain and urban surroundings.

In the hospital Dad shared with me, "I had the greatest temptation to try and turn back to the runway, but forced myself to fly straight ahead and make the best controlled crash I could"

V/R
Smokey

As you mentioned: "Fly the airplane as far into the crash as possible...."
Bob Hoover
 
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RV-6 Head on collision w/a dump truck

I met an NTSB accident investigator some years ago and he told me about an RV-6 accident he worked the report on. It had an engine failure over urban L.A. and the only place for the pilot to put it down was a California DOT parking lot, so he dropped it in there. He barely cleared a hook and ladder fire truck, then bounced a few times before going beak to beak with a parked dump truck. The pilot and co-pilot were thrown forward by the rapid deceleration, and their shoulder harnesses (hooked to the aft longerons) compressed the tail together until it couldn't do that any longer, and then the double row of rivets connecting the cabin to the tail-cone section failed. The tail-cone then slid forward and both occupants lacerated their heads pretty good on the instrument panel, but both survived. No mention of the G loading in the report, but it seems it must have been pretty high; and by limiting the vertical G-load component by flying the a/c to the ground; they no doubt kept from dying from internal injuries such as a detached heart artery, etc.

Doug Lomheim
RV-9A
 
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