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Amazing video of RV nose gear collapse shot with GoPro

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Is that rust on the three bearing surfaces??....:eek:

Watching the video frame by frame,it looks like the wheel bearings were bound during the first hit (look for a two part mushroom type axle)
and was not free to rotate when it contacted the ground the second time.
 
Bound or was it a low coefficient of friction coupled with the mass of the tire?

[true, open question - in consideration of "other factors")
 
Keep your seat harness tensioned

A number of posters on this thread asked if the accident pilot had a 4 or 5 point harness. The pilot subsequently responded by saying that he had a 5 point harness and that he believed that it was ?adjusted adequately?. Despite this, the pilot reported that he hit his head in the flip over and he believed this led to his neck being broken. The aircraft had a slider canopy and the pilot did not believe that the roll bar was deformed during the tip over.

This is somewhat disconcerting as I had intuitively always felt that the slider canopy with the roll bar in front of the pilot would offer better head protection than the tip-up canopy with the roll bar behind the pilot. I still think that this is true.

All things being equal the RV6(A) offers less headroom than all of the subsequent side by side models. I?m 181cm (5?11?) and I find there is very minimal headroom in an RV6(A) with a headset on. I have more headroom in my RV7(A) but there?s not a lot of head clearance there either.

I think this accident speaks volumes about the necessity for RV pilots to have 5 point harnesses, and to keep them firmly tensioned, particularly during landings on unmade strips....and even more so in the RV6(A) which has minimal head clearance.

The propensity for RV(A)s to tip over if the nosegear fails is huge (and the nose gears have a very poor record)...so best to keep those harnesses well tensioned on landings in order to give yourself the best possible chance in the event that the landing does not go to plan.
 
A Despite this, the pilot reported that he hit his head in the flip over and he believed this led to his neck being broken.
One of the issues about the injuries here that many people don?t realize (because they are of average ?build?) is that SITTING height varies widely. I am of average height (5-10) but have an extremely high sitting height (and relatively short legs) so always end up putting a seat all the way down or nearly so whenever I have that option. In an airplane I flew in a previous career, I HAD to have my seat all the way down in order to aim correctly.
I am always thinking about the possibility of breaking my neck in any moving vehicle because of this. Looking over the RV-8A I am in the process of buying, I discovered I will have to replace the seat cushion (since there is no option of lowering the seat!) so my noggin is not bumping the canopy just sitting there. I was also amazed that there are no headrests to prevent whiplash injuries and will be looking into those options.
 
Part 1

I read through this thread and would like to put down my thoughts here. I have only become aware of this issue recently because I am looking at an RV-8a to buy here locally – I would prefer a TD, but sometimes you have to look at what’s availble. I must say when I was told by a local RV-4 owner to beware of the tricycle RVs because the nose gear has a tendency to collapse, that got my attention. At least the 8a that I am looking at has the Anti-splat mod, which I believe will lower the chances of a collapse/flip, but still...

I really appreciate the video that this unfortunate pilot was able to provide. I have done my own personal analysis of it (I am an analyst) and come to some of my own personal conclusions. I have also been on three accident investigations so have some experience in the matter. Hopefully I don’t offend anyone because my personal opinion, based on my analysis (though of course limited to watching videos and studying pictures of damaged -XA nose gear, and looking at the nose gear on my prospective plane) is that the RV-xA nose gear is a very flawed design. I find this surprising since I so admire Van’s ability to create simple, safe, efficient and high performance aircraft designs.

First, there was a lot of talk about “the pilot was too fast, the landing was too hard, he should have held the nose wheel off longer,” etc. These are probably all true but mostly irrelevant in my opinion, because (again, only based on watching the video - multiple times, at multiple speeds) the landing appeared to be within normal limits that the average pilot flying an RV should expect to occasionally deviate to – part of the safety factor that all planes and their parts are generally designed to. No pilot is expected to fly perfectly all the time and one shouldn’t have to worry about the nose gear collapsing and flipping your airplane over because you deviate outside of nearly perfect parameters. And no I am not saying a pilot should be able to drive his plane into the runway nose gear first and expect it to take the abuse, but again, the video showed a landing that I considered to be within the parameters of what landing gear should be able to easily survive.

As far as operating on dirt/grass/unimproved runways, one of the advertised advantages of Van’s aircraft is their ability to land and take off in short distances. So, logically, those aircraft should be designed to operate on said unimproved runways since there aren’t a lot of perfectly paved 1000’ runways.

OK, now I’ll get into the specifics of the design. It’s clear why the nose gear is angled forward – to get the mounting point at the fire/wall engine mount point and bring the wheel as far forward as possible for ground stability. Lots of planes utilize this basic design. The idea being that the elastic steel pipe will flex up and down (at the 45 or so degree angle so slightly forward and back as well as up and down) as it encounters bumps, ideally, when the wheel encounters a disturbance, we would expect the primary flex to be up, away from the disturbance. Also, the flex should be distributed along the strut more towards the end and less towards the top (why most gear that flexes is tapered). However, if we look at other videos of -xA nose gear in operation, and especially this video, we see that the gear does not flex along its length, but mostly pivots at the top rear of the assembly, very near the mounting point. You can see this clearly because you can see the nose strut fairing moving considerably at the cowling and the entire strut below that point appears to remain stiff. This causes a (more than normal) negative dynamic in the flexing process – the gear encounters an irregularity in the runway (or anything to apply a rearward force to the nose gear) and this flexes the entire gear tube back and down, which puts more force on the gear, which bends it back and down further, etc.

It would seem this happens every time a -xA nose gear touches down, but the majority of the time, the stress is relieved before plasticity deforms the gear, with a combination of the tire flexing, the fuselage rotating up in pitch, and/or the runway obstruction being passed. You can see this in the video – both times the front wheel touched, the flex is initially back and down – the first time the entire plane bounced a little so that relived the pressure on the nose gear and no deformation occurred. The second time, the plane had downward momentum as the nose wheel touched, and the back and down force reached the plastic deformation stage before the increasing force applied could be relieved by some other factor. You can see this on a normal (not catastrophic) landing: https://www.youtube.com/watch?v=QpS3JzUIgTE – nose gear touchdown occurs around 4:40, and, as is usual, the first flex is back and down. The tire absorbs some of this and the fuselage rotates up slightly in pitch. The tire pressure aspect of this issue has me thinking too. I saw several propose increasing the tire pressure to make sure the gear assembly is kept well away from the ground. But this also lessens the tire’s ability to absorb some of those bumps. That would be a whole ‘nother case for analysis right there.

Here’s an SR-22 with similar gear.: https://www.youtube.com/watch?v=jT4fOehZKNs -Watch at 0:45 as the nose wheel touches down, even with severe shimmy, the initial and most flex is up, not back and down. It would appear that the -xA nose gear strut is at the worst angle – and probably has another factor contributing that I do not have enough information to figure out yet – that causes that consistent back and downward flex.

There was a lot of discussion about what causes the backwards force besides runway deformities – like a seized or tight wheel bearing – but those are conditions that are ‘normal’ deviations and one should not expect a tight wheel bearing, or a slightly off tire pressure, to lead to your plane flipping on its back.

To me it’s obvious that a back and down action of a nose gear is exactly the opposite of what should be happening. We want a back and UP action that is naturally dynamically stable in absorbing runway irregularities. The wheel encounters a bump, the force is applied backwards and the tire rotates backwards and upwards. Or in the case of a straight (or slightly angled forward nose strut - think Cessna) the runway bump applies a backwards and upwards force, and the backwards force is mainly re-directed up along the strut, which retracts, relieving the force. It’s the round tire that rotates and re-directs a rearward force from a bump up along these struts. It appears the tire on the -xA does NOT do that most of the time in the videos I’ve seen. My guess as to why is that too much flex is inherent at the top of the strut and that long moment arm contributes to all the problems I’ve been discussing.

If nothing else, the gear strut should be redesigned so the flexing happens at or near the wheel, not at the mounting point of the strut, and so the flexing is up, not back and down. Ideally, a trailing link should be used. This is relatively simple and would integrate very well with the current nose strut configuration. It also works well with the pivoting nose wheel steering. When a bump is encountered, the wheel fork pivots backwards and upwards, decreasing, not increasing, the force applied to the strut. A simple rubber dampened spring would absorb the force and prevent bounce. Even a design such as on the Pulsar - http://www.eaa1246.org/projectsnplanesdisplay.asp?id=23&pic=42 - would work much better than the current Van’s design, and most likely add little extra cost.

----continued in next post----
 
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Part 2

--- continued from previous post ---

The other aspect of the RV-8A specifically (I’m unsure the extent of how this applies to the side-by-sides) is the distribution of weight on the nose-gear. As I started looking at my prospective RV-8A (180hp, constant speed prop), the seller sent me the weight and balance calculator spreadsheet. I was rather amazed – assuming the spreadsheet is correct, and it is the standard one I believe someone in VAF produced – that the weight on the nose gear is approximately equal to each main gear at empty weight. Even when in the heart of the envelope – two 170 pound occupants, full fuel, no baggage – the nose gear supports 360 pounds, a mere 15 pounds below the Van’s maximum. This is also 21% of the total weight. It gets much worse with a single occupant. Take away the rear occupant, and the CG moves beyond the forward limit. You then must add ballast to the rear baggage area to move the CG back into the envelope. If I add 25 pounds ballast to the rear shelf, the aircraft is within CG, but there is still 404 pounds on the nose gear. So I have to add ANOTHER 40 pounds to the rear baggage area to reduce the weight on the nose gear (at takeoff) to the maximum allowable 375 pounds. And that is 23.6% of the aircraft total. At landing, if I have 20 gallons remaining, the nosewheel supports, statically, less weight (343 lbs) but about the same percentage at 23.4% since the fuel tanks are close to the CG, obviously. Only at max gross weight, max aft CG (not a comfortable place to be in my opinion) does the static nose gear weight get down to 15% of max gross.

I’m not sure what Van’s was thinking here. I’m sure some could be attributed to the IO-360/constant speed prop combo, but again, wasn’t that one of the reasons Van’s went from the 4 to the 8? This is very much against standard tricycle aircraft gear design. The main weight of the aircraft is supposed to be borne by the main landing gear, and the nose gear is to provide directional stability, keep the nose of the aircraft off the ground (since the center of gravity is forward of the main gear) and absorb the braking forces as the brakes are applied, which pitches the aircraft forward and increases the effective weight (dynamic force) on the nose gear (indeed, one of the reasons aircraft made the jump from tail-dragger to tricycle). It is NOT supposed to be the equal third leg of three (or nearly so). One reason it is not supposed to support so much of the aircraft weight is because this greatly increases necessary rotation forces. Jenkinson, (Civil Jet Aircraft Design – though should be similar for light aircraft) recommends a static load of at least 8% weight on the nose gear but no more than 15%.

So for me, considering all this, it makes me uncomfortable that the aircraft has, what I consider, a significant (could lead to significant injury or death) faulty design that could have (relatively) easily been fixed by Van’s. I don’t think anyone should dismiss this as a non-issue (and certainly not it’s-all-the-pilot’s-fault).
 
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I read through this thread and would like to put down my thoughts here.
<Huge snip>

--- continued from previous post ---
<another huge snip>

I added paragraph breaks to the two above posts since they were difficult to read as originally posted.

However...there is no new info in the posts, all the comments about the Vans gear design have been previously discussed extensively in multiple threads over the years.

Did you purchase the dangerously flawed RV-8A? :)
 
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Happy 7A owner

Reading the lengthy previous thread trashing the current nose gear struck a nerve. I take offense to the ?expert? opinion that the nose gear is so poorly designed, especially from a non RV owner. Personally, I have been very pleased with the performance of my nose wheel model (7A) and have absolutely no safety concerns.

Jim Diehl 7A
Lock Haven, Pa
 
Van's redesigned the gear on the -14A to FAR 23.726.

Retrofitting a -7A nose gear to this standard looks like money well spent to me.

Did Vans test the new landing gear on the -7A to the FAR standards? Or did they just come up with a similar design and that's it?
 
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I read through this thread and would like to put down my thoughts here.

I first have to admit that I didn't read your entire personal report/opinion.
I did quickly scan it though and noticed that it appears to be missing any mention or reference of a very important data point related to this very unfortunate accident.

That is, that the investigative report said that the indicated airspeed at initial touchdown was 75 Kts!. For those not familiar with the RV-6(A), that is in the neighborhood of 40% over nominal.

I will limit my comments to that.
 
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When I catch up with a mate of mine in my 8 (proper version) he gets a little envious cause his training wheel version of the 8 looks awkward sitting next to mine:) He looked into converting it but it's a big job lots of $$$$. He keeps the CG at its most rearward point all the time, makes him feel more comfy:)
Each to their own and that's why Mr Vans produced the training wheel machines, to appease all:)
 
Van's has already corrected they're perceived design flaws in the -7A nose gear. No need to notify them.

If you read the document the link leads to (or any that have been published in the past related to the nose gear), you will see that it has never been referred to as having a design flaw.
In fact just the opposite.

The nose gear, as designed, has done a good job of meeting the original design goals.

The new design was developed based on customer request, to have an option for a nose gear similar to the RV-10 and 14A.
 
If you read the document the link leads to (or any that have been published in the past related to the nose gear), you will see that it has never been referred to as having a design flaw.
In fact just the opposite.

The nose gear, as designed, has done a good job of meeting the original design goals.

The new design was developed based on customer request, to have an option for a nose gear similar to the RV-10 and 14A.

That's why I said "perceived design flaw". Poor wording, I'll edit that post.
 
That's why I said "perceived design flaw". Poor wording, I'll edit that post.

My misunderstanding then, but the way I interpreted it since you had actually written "They're perceived design flaw". (though "they're" should have been their, so maybe you meant something else).
 
That is, that the investigative report said that the indicated airspeed at initial touchdown was 75 Kts!. For those not familiar with the RV-9(A), that is in the neighborhood of 50% over nominal.

I have some doubt about the figures presented by the ATSB. They also say the rate of descent at touchdown was 700 feet per minute, which I don't think is backed up by the video.

If landing technique causes dispute, perhaps we can talk about the RV where the nosegear collapsed on takeoff from a rough runway (Avalon East at the Avalon Airshow in Australia)?

I think there is a geometry problem with the nosegear, rather than strength.

All forces from the wheel into the leg must act through the axle. If the wheel turns freely it can't generate a torque force - the force must be a straight line from the tire through the axle.

Draw a line parallel with the gear leg forwards from the axle to the outside of the tire.

Any bump impacting at that point of the tire (or above) cannot be absorbed by the main part of the gear flexing. A bump at that point of the tire puts the upper part of the leg in compression - there is no bending force. The bump can only be absorbed by the lower section curling backwards.

Perhaps someone can measure how high off the ground that is i.e. how large a (sharp edged) bump is likely to collapse the gear?

I agree with ARV8or who says that it needs a trailing link that can absorb larger bumps by pivoting up and back, rather than relying on the forward flex in the upper leg.
 
Reading the lengthy previous thread trashing the current nose gear struck a nerve. I take offense to the ‘expert’ opinion that the nose gear is so poorly designed, especially from a non RV owner. Personally, I have been very pleased with the performance of my nose wheel model (7A) and have absolutely no safety concerns.

Jim Diehl 7A
Lock Haven, Pa

You shouldn’t take offence. The relevant post pointed to perceived shortcomings in the original nosegear design. I think we can assume that when Vans recently completely redesigned the RV7A nose gear they did so because they acknowledged privately (but not publicly for obvious legal reasons) that the original design had a very marginal safety factor.
 
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If landing technique causes dispute, perhaps we can talk about the RV where the nosegear collapsed on takeoff from a rough runway (Avalon East at the Avalon Airshow in Australia.

There’s no reason for a nose gear failure on takeoff other than poor pilot techniques. The nose wheel can be raised at taxi speed when full throttle is applied. Even with a forward CG the nose can be raised within a few feet of takeoff roll. The speed is too low to collapse the nose gear.

-Andy
 
You can see this on a normal (not catastrophic) landing: https://www.youtube.com/watch?v=QpS3JzUIgTE – nose gear touchdown occurs around 4:40, and, as is usual, the first flex is back and down. The tire absorbs some of this and the fuselage rotates up slightly in pitch.

I have watched the video (referenced above) at .25 speed with a marker on the screen aligned with the hole in the nose pant and can't see the behaviour you describe. Possibly there is a very very slight flex back at touchdown but this would be expected with the high drag from the initially stationary nose wheel. Subsequent oscillation appears to be substantially forward.

Viewing the video in Post #1 again, my take is that the initial somewhat hard/fast touchdown causes the strut to oscillate excessively. The subsequent touchdown appears to be near the side of the strip in an area of sand with the strut at the aft end of the oscillating range??

I have over 1,000 landings on grass and believe the strut to be adequate provided the bottom of the nose cone/bottom of the strut does not contact the ground.

Fin
9A
 
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One of the issues about the injuries here that many people don?t realize (because they are of average ?build?) is that SITTING height varies widely. I am of average height (5-10) but have an extremely high sitting height (and relatively short legs) so always end up putting a seat all the way down or nearly so whenever I have that option. In an airplane I flew in a previous career, I HAD to have my seat all the way down in order to aim correctly.
I am always thinking about the possibility of breaking my neck in any moving vehicle because of this. Looking over the RV-8A I am in the process of buying, I discovered I will have to replace the seat cushion (since there is no option of lowering the seat!) so my noggin is not bumping the canopy just sitting there. I was also amazed that there are no headrests to prevent whiplash injuries and will be looking into those options.

"Whiplash" injuries are not a significant risk in aircraft. Whiplash is a VERY specific injury mechanism that occurs as a result of a rear-end collision in an automobile. That is why headrests were invented and eventually mandated...in cars. Headrests provide zero protection from other mechanisms of cervical injury, including those that would more typically occur in aircraft accidents. There are many ways to sustain injury in aircraft accidents, but being hit from behind is one of the less likely ways, I would think. The only aircraft seats that really need head support are ejection seats, where head restraint is needed to prevent hyperextension of the neck during the 20+G loads that occur during ejection. I speak from the perspective of a career physical therapist who treated many, many cervical spine injuries from motor vehicle accidents and other mechanisms of injuries (including several military training ejections, incidentally), and who took many post-graduate courses on the cause and treatment of these injuries.

Your point about people of the same height potentially having very different biometrics is a very good one; I am 6'3", with my height in my long legs. My brother is 2" shorter, but with shorter legs and a longer torso, so he "sits higher". One option that makes a huge difference in this department in a side by side slider RV (and therefore relevant to this thread, although not to the RV8 you are purchasing) is the "Almost an RV14" mod from Antisplat. It reclines the seatback further than stock, providing a huge increase in headroom. I just fit with very little clearance with the stock setup. With the mod, I wear a helmet and still have good clearance above my head, as well as an extra margin of safety before head contact with the canopy or the ground in the event of a flip. Would, or could, this have made a difference to the injuries sustained by this pilot? Hard to know, but it certainly seems possible. I have a friend who had a virtually identical landing flipover in his just-completed 7A; came in to his short grass strip hot, landed on the nose gear, with precisely the same outcome as in this accident. He is a tall guy, and likewise suffered a cervical fracture, but he was very fortunate and was properly stabilized on scene, had a fusion, and ultimately fully recovered. It seems logical that anything that lowers your head relative to the canopy and the roll protection will decrease the chances of severe head or neck injury.
 
There is a mechanism for "whiplash" and this accident points right at it...

A forward flip, then sudden stop would be the same as being rear-ended.
 
"Whiplash" injuries are not a significant risk in aircraft. Whiplash is a VERY specific injury mechanism that occurs as a result of a rear-end collision in an automobile. That is why headrests were invented and eventually mandated...in cars. Headrests provide zero protection from other mechanisms of cervical injury, including those that would more typically occur in aircraft accidents. .

I believe there is a high probability of whiplash from sudden stop and then the (recoil?) force of slamming back into the seat.
 
Reading the lengthy previous thread trashing the current nose gear struck a nerve. I take offense to the ‘expert’ opinion that the nose gear is so poorly designed, especially from a non RV owner. Personally, I have been very pleased with the performance of my nose wheel model (7A) and have absolutely no safety concerns.

Jim Diehl 7A
Lock Haven, Pa

Well, I believe I didn't "trash" anything. I don't think it fair to call my personal observations, which I carefully backed up with my personal analysis, trashing something just because you may disagree with me. But I did expect this - why I said "I hope I don't offend anyone." There's always someone...
 
I believe there is a high probability of whiplash from sudden stop and then the (recoil?) force of slamming back into the seat.
What would provide the force to "recoil" someone into the seat? There are no springs or recoil mechanisms in most light aircraft. More likely would be the seat hitting you in the back as the rest of the airplane comes to a stop after you do.
 
I believe there is a high probability of whiplash from sudden stop and then the (recoil?) force of slamming back into the seat.

This is the mechanism associated with a front-end type collision in a car, but technically is not defined as "whiplash" and is associated with significantly less severe injury. When the initial movement of the head is forward relative to the body, the effect is much less dramatic and much less injurious than when the initial movement of the head relative to the body is backward. With the latter, the neck starts by hyperextending (snapping backward), then hyper flexes (rebounds forward). Along with the injury to the neck, the brain is rattling around in the skull; it bounces off the front of the skull as the head snaps back, then off the back of the skull as the head rebounds forward, resulting in much greater likelihood of concussion as well. All of these effects are significantly reduced with a front impact resulting in the initial forward movement of the head, which the much stronger muscles on the back of the neck are more able to damp than when the forces are reversed and the weaker muscles on the front of the neck are trying to resist the backward (extension) forces. All of this is not just my anecdotal experience or opinion; it is a summary of 50 years of research around the world. This costs insurance companies many millions of dollars every year, so they have poured millions into studying it.

In a flipover, the initial force would be to snap the head forward as the nose gear digs in and rapidly decelerates forward movement of the plane (much like a front-end collision in a car). Once it goes over, the empennage will dig in and result in opposite forces, yes, but a great deal of the energy will have been dissipated already, and the forces and accelerations will be correspondingly less. The pilot in this accident said that he was quite sure that his neck injury resulted from his head hitting the canopy; a vertical, compressive force. That was also the case with my friend in his RV7A flipover; his neck injuries were a result of forceful compression of the c.spine. This is by far the greater risk in these accidents, and safety features designed to lessen the effects of whiplash will simply not help with this mechanism of injury.
 
What would provide the force to "recoil" someone into the seat? There are no springs or recoil mechanisms in most light aircraft. More likely would be the seat hitting you in the back as the rest of the airplane comes to a stop after you do.


It's actually the opposite; the aircraft decelerates first, and your head lags behind, then continues moving after the plane, and your body, stop. The movement of our bodies relative to the seat is quite limited if we are wearing belts with shoulder restraints, so what is still free to move and gets left behind is your head.
When you get hit from behind, your car seat moves forward immediately, but your head lags behind, resulting in a relative backward movement of the head on the body. Then, as your body stops moving forward, your head accelerates and catches up, but inertia being what it is, your unrestrained head overshoots your body and snaps into injurious flexion. The "recoil" is good old inertia at work, with your body locked to the car, or aircraft, and your head unrestrained and trying to catch up, just like the end of a whip. In a flipover, the forces are simply reversed, but much less dramatic when the initial force is forward deceleration of the aircraft. The "recoil" into the seat will result from the final deceleration of the aircraft as the tail digs in and arrests the remaining movement, which is now backwards; seatback stops moving; head keeps going.
 
There is a mechanism for "whiplash" and this accident points right at it...

A forward flip, then sudden stop would be the same as being rear-ended.

Exact opposite; the initial deceleration is forward, equivalent to a front-end collision, as the nose gear digs in.
 
Exact opposite; the initial deceleration is forward, equivalent to a front-end collision, as the nose gear digs in.

This is my thought as well. Once you're going upside down, the majority of your motion is vertical, towards the ground. Very little "forward" (or tail pointing forward) motion remains after the engine has dug in, to give you any whiplash back into your seat.
 
What would provide the force to "recoil" someone into the seat? There are no springs or recoil mechanisms in most light aircraft. More likely would be the seat hitting you in the back as the rest of the airplane comes to a stop after you do.

For sake of the conversation, no two accidents are alike and the shoulder harness seat belt system stretches much more that most realize and then may pull you back. I remember years ago that Wayne Handley crashed the turbo Raven and video was dramatic in illustrating this point. The only one I can find now is low resolution but is still a good example of some of the various dynamics affecting a body during a crash. If you watch this in slow motion you can see Wayne nearly get ejected from the airplane and pulled back in. The second impact is the most violent. The aircraft also turns and slides backwards before coming to a stop.

https://www.youtube.com/watch?v=BJWjbpA_zIc
 
Wow; that is a lot of vertical g-force. I would be shocked if he didn't suffer compression fractures with that impact. He is fortunate to be alive for sure. As a side note, I shared my hangar for 5 years with a former Snowbird pilot who now flies a Pitts as a civilian airshow performer (Brent Handy). He did all his Pitts training with Wayne about 6 years ago.
 
Wow; that is a lot of vertical g-force. I would be shocked if he didn't suffer compression fractures with that impact. He is fortunate to be alive for sure. As a side note, I shared my hangar for 5 years with a former Snowbird pilot who now flies a Pitts as a civilian airshow performer (Brent Handy). He did all his Pitts training with Wayne about 6 years ago.

Brent is currently enroute from Mexico to the USA east coast on their sailboat. Nice fellow, nice family...looking forward to some flying.
 
Wayne's Tale

Wayne did indeed have some serious spinal compression injuries, to the point he figured he'd never fly again. But he did, and even did some airshows. Great guy.
 
For sake of the conversation, no two accidents are alike and the shoulder harness seat belt system stretches much more that most realize and then may pull you back.
No. Neither nylon webbing nor the common cables used to attach it to the airframe (where it's not bolted directly) have any significant "springiness" to provide recoil. They're designed specifically to absorb the impact by stretching *without* recoil, as snapping back like a rubber band could cause further injury in an accident.

If you watch this in slow motion you can see Wayne nearly get ejected from the airplane and pulled back in. The second impact is the most violent. The aircraft also turns and slides backwards before coming to a stop.
You must be seeing something i'm not. He is almost ejected, yes, but only to the limits of his restraint's travel, before gravity pulls him back in... That's not "recoil." And while the plane is turning and sliding to a stop backwards, you don't see his head moving aft.
 
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There?s no reason for a nose gear failure on takeoff other than poor pilot techniques.

-Andy

On the contrary, I would say there?s no reason for a nose gear failure on takeoff other than poor nose gear design.

I fully understand that good takeoff procedure in an RV(A) is to lift the nose gear off the ground during the takeoff run as soon as there is elevator authority available to do so...and I am not advocating any other technique. However for those who insist in barrelling down the runway and pulling the nose gear off the ground at rotation the price should not be a nose gear collapse which is what happened at the Avalon Airshow. Any valid nose gear design should have enough structural redundancy to put up with this type of poor take off technique. After all, this is the type of take off technique employed by 90% of private pilots.

Just go to any busy general aviation airfield and watch the light aircraft take off....virtually no one lifts the nose gear off the ground earlier than rotation. Terrible technique admittedly, but any reasonably designed nose gear should be able to comfortably put up with that punishment. If it can?t then that simply means the safety margin is way too slender.
 
the price should not be a nose gear collapse which is what happened at the Avalon Airshow.

If this occurred on a properly maintained / paved runway, then I would contend that there are other extenuating circumstances that haven't been provided, that could possibly provide an explanation.

It is unreasonable to lump every single failed nose gear accident that has occurred on RV's into the same group and state that if only the nose gear was designed as it should have been, that none of those accidents would have occurred.
It is basically saying that anything designed correctly should not be able to be broken by any user. Taking that position is just plain wrong.

You have not provide any info other than an accident ended with a failed nose gear that occurred during take-off in an A model RV. That in itself does not mean that the fault is with the design of the airplane.

Now if this accident occurred on a dirt / grass runway, the fact that a large percentage of pilots use poor technique for every take-off is also not a reason to cast blame on the airplane.



I have a serious question.

If an airplane should be able to survive any level of technique (in some instances maybe "abuse" would be more appropriate), why do you suppose there is so much emphases on training pilots to use soft field take-off and landing techniques (at least it is a standard here in the U.S., so I assume elsewhere as well)

The answer is - Because the nose gear on a tricycle geared airplane takes the most abuse and is probably the most vulnerable component on the airplane to damage by the typical user.

If the contentions that are often made were true (most pilots fly the same... nose gear stuck to the runway, properly designed airplanes can always tolerate what ever techniques the average pilot uses, etc.), then why would the people that have been in charge of developing and evolving the training curriculum's have every added soft field take-off and landing techniques to the syllabus?

And by the way, the proper definition of a soft field runway surface is not a muddy farm meadow out behind the barn where your airplane will be covered with mud after landing or taking off.

It is any surface that is not hard (meaning concrete or asphalt).

Why?

Because the surface condition of any soft field runway has a high chance of having issues today, that weren't there yesterday.

One thing we can agree on is that a large percentage of the pilot community has obviously forgotten at least some of the basic fundamentals they were taught while training to be a pilot.

Hopefully discussions like these will cause us all to do some self evaluation on a regular basis and look to improve in areas that we might be deficient.

A personal tool I use is to ask my self...
Is there anything (piloting skill, knowledge, etc.) that I can think of that if I needed to perform it for an examiner on the next flight I make as pilot(meaning not going out and doing some advanced practicing or study prep.), that I couldn't do it to well beyond the minimum standard I had to meet when I because a pilot.

When we pass an examination for any rating we have shown that we at least meet the minimum requirements.

Anyone that has been flying for quite a while should be able to easily exceed all of those minimums.
If there is something that they think they probably couldn't, that would be a very good thing to personally challenge yourself with improving on.

Remember... many of the skills we are taught are things that are not going to be used on a regular basis.
Soft field take-offs and landings are a good example.... emergency forced landings are another.
Often times when we need to utilize those skills, we aren't provided the opportunity to practice for a while before we execute them.
 
When this topic comes up, I often think about the RV-6A that Mike Seager operates out of Vernonia. That airplane has thousands of hours, and likely tens of thousands of landings. It does not have any third-party nose gear modifications, operates out of the grass runway at Vernonia for at least two takeoff and landings everyday, and is used exclusively for training.. aka: it sees a lot of less than perfect technique.

The nose gear on this aircraft hasn't collapsed. Why? Could it be that Mike does not allow the airplane to continue the approach when it's too fast, too high, about to touch nose first, or three pointed? Instead, opting for go around and trying again? If so, does this perhaps imply that perfect technique is not required, but rather just something better than an abusive technique?

Van's has alluded to the fact that design choices were made with the nose gear that perhaps make it less robust than something that is over engineered and more tolerant of abuse. (See this short piece) But, just because the nose gear is less tolerant of abuse, that does not mean that it's poorly designed.

Scott -- Do you have any info on the number of hours and/or landings on the RV-6A that Mike has Vernonia?
 
Scott -- Do you have any info on the number of hours and/or landings on the RV-6A that Mike has Vernonia?

I do maintenance on it but I do not from memory recall what exactly the total time is, but I believe it is somewhere around 5000 Hrs.

Total number of landings? That is anyone guess.

I have probably done at least 100 myself. Many of them at Vernonia and the grass runway at Sunset Airpark where Van's flight operations used to be based at.
 
If this occurred on a properly maintained / paved runway, then I would contend that there are other extenuating circumstances that haven't been provided, that could possibly provide an explanation.

It is a temporary dirt strip adjacent to the main airfield, and has a reputation for being rough. However it is set up by the operators of an international airshow and generally considered adequate for GA aircraft.

What forces on the leg do your computer tools show as the size of a sharp edged bump increases i.e. as the impact point moves forward and up on the front edge of the tire?

It appears to me that there is a point (not very high) where the force acts in line with the main part of the leg, i.e. the only spring available is the lower part curling backwards.
 
What would provide the force to "recoil" someone into the seat? There are no springs or recoil mechanisms in most light aircraft. More likely would be the seat hitting you in the back as the rest of the airplane comes to a stop after you do.

Watch any crash test dummy video of car crashing into a wall. No impact from behind. Even take out all of the ones with air bags. Virtually every one of them shows the dummy reaching the limits of seatbelt/body flex and then recoiling/rebounding (whatever) back into the seat. I would imagine a lot of that is from the 'springiness' of our own bodies.
 
Saw another training wheel Vans come close to 'Q' tipping his prop the other day! He was damned lucky he stopped before the nose dug in and he became another statistic!
 
Watch any crash test dummy video of car crashing into a wall. No impact from behind. Even take out all of the ones with air bags. Virtually every one of them shows the dummy reaching the limits of seatbelt/body flex and then recoiling/rebounding (whatever) back into the seat. I would imagine a lot of that is from the 'springiness' of our own bodies.
In all of the videos i've seen, if you watch them carefully, you'll see that the car itself bounces off the wall while the dummy's body is in contact with the steering wheel, airbag, windshield, seatbelt, etc. The car is then moving backwards, and when it stops the body keeps going backwards. In a lot of the ones I just found, the body reaches the limits of the belt, and then just falls back into the seat. It's not a "rebound", it's just gravity pulling the occupant back into the seat as everything comes to a stop.

I haven't seen any slow-motion videos of a crash test dummy in a light aircraft cockpit during a turnover event... But it will happen a lot slower in terms of impact, as the nose first digs in, then rotation starts, then the plane inverts, all slowing down the entire time.
 
Only as good as your last landing

I would like to think that this thread and the unique video of the RV6A nose gear collapsing in Post #1 may have highlighted the limitations of the original spring steel RV(A) nosegear and encouraged pilots to adopt better landing (and take-off) techniques that minimize the stresses on the nose gear...namely keeping the nose gear off the ground while there is any elevator authority available to do so.

Hopefully pilots might also be a little more circumspect about landing on unfamiliar unmade strips. And finally it might have brought home the importance of having a 5 point harness and having it firmly tensioned upon take-off and landing.

It has been a huge thread with many excellent viewpoints and has been conducted in a very civil and productive manner.

I would like to take this opportunity to once again thank Ian Smith for allowing his video to be released on VansAirforce. The outcome for him has been totally devastating in that he was left as a quadriplegic.

That raises a relevant point in that we tend to view the severity of GA aircraft accidents purely in terms of fatalities. But the truth is that for every fatality there may be half a dozen very serious injuries...many of them resulting in permanent disabilities.

The old saying that the drive to the airport is the most dangerous part of the flight was always nonsense. Flying in sport aircraft is an intrinsically risky business, particularly in home built and home maintained aircraft.

As I like to say, it doesn't matter how long you've been flying.... you're only as good as your last landing.
 
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I watched in close proximity a 7A launch over the W/E from an unimproved surface and the driver didn't hold any up elevator till it was time to rotate, the nose wheel was excruciating to watch! Forget about his poor airmanship prior to take off but the few of us observing his actions where almost convinced here we go again!
 
Roll Over Protection

After seeing this thread I tried to search a lot before asking this question, but I couldn't find any answers.....

We were on the cusp of buying the 14A kit and now I'm having serious concerns about egress in a flip over. How is one to escape a flipped Van aircraft??

[Moderator note: This is a valid question and one that has been discussed numerous times over the years. The archives are your friend or you might post an inquiry in a new thread; S.Buchanan]
 
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When my RV is done, you can bet I'll have a canopy cracker on board and easily accessible, but I really believe that it's going be a similar situation to any other low wing airplane. If a piper flips over, it's not likely that you'll be able to fling open the door in than squashed door frame.

My friend flipped his RV6 last summer while landing at his home grass strip. I was sitting in the hangar doorway with his wife and another couple and literally saw the dust settle. By the time we hopped on a 4 wheeler and blasted up to the other end of the grass strip (maybe 2 minutes?), he had crawled out through the broken canopy.

I know that it doesn't always work out this way, but in that case, the airframe held up surprisingly well. I crawled back into the airplane to shut off the fuel and master and while it was incredibly disorienting, it wasn't really that confined. He was a little banged up, but his most significant injury was bloody shins where they had smacked the bottom of the panel.

Also, FYI- the RV14 has a different nose gear design than the previous Vans trikes

Not trying to minimize your concern at all. I was really expecting him to be hurt until we approached and saw him standing there. I'll never forget him commenting a few minutes later "We'll, I guess I'm one of those guys who's wrecked an airplane."
 
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