Mudgee

[dutchroll]

I think sensible but respectful discussion (and yes I know that's sometimes a fine line) on accidents and incidents is what this forum was created for. I sincerely hope this forum doesn't turn into an obituary column where talking about accidents and incidents becomes too hard for fear of causing offence.

 

 

[Dafydd Llewellyn]

I hope people are not offended by discussion that may help others to avoid becoming accident statistics. If it leads to better understanding, some small benefit can be derived from events that we would all prefer had not happened. We should, I believe, strictly avoid speculation or anything that might prejudice an accident investigation or imply blame; but that surely does not mean that potentially relevant facts cannot be mentioned?

 

 

[rgmwa]

Dafydd, do you know whether Vans took any subsequent action to strengthen the sides of RV cockpits following those two accidents you investigated?

 

rgmwa

 

 

[Dafydd Llewellyn]

Dafydd, do you know whether Vans took any subsequent action to strengthen the sides of RV cockpits following those two accidents you investigated?rgmwa

No, I have no idea whether they did anything; I think they took the position - not entirely unjustifiably, I feel - that those accidents were unsurvivable anyway. But I note that later models seem to have rather greater tailplane span.

 

 

[turboplanner]

The report that both people were out of the aircraft and walking around after the crash came from here http://www.pprune.org/pacific-general-aviation-questions/547532-prang-mudgee-14-9-14-2-dead-2.html, post#31 mcoates, who quoted a person who lives next door to the accident site and is a pilot.

 

There are other reports that the pilot was extracted from the aircraft.

 

There are witnesses who say the engine had stopped and the pilot was trying to restart it, and that the aircraft dropped out of the sky.

 

There is also a report of considerable radio traffic during the incident.

 

So a lot for ATSB to go on and verify.

 

In the meantime, unless the pilot has suffered a crush injury described above, it seems to me the aircraft survived its drop out of the sky well, so doesn't need the finger pointed at it just yet.

 

There would have been a considerable G force applied to the occupants on collision to the ground, but that aspect will be investigated.

 

Why the pilot didn't just make a forced landing into a paddock when the engine failed would be the question to be answered if we are to take lessons away from this.

 

Given the stall reported, I wouldn't be too concerned about the condition of the structure of the RV6, and I wouldn't be comparing it to a Jab unless a crush injury emerges. If it was a G force injury, than the type of aircraft is irrelevant.

 

 

[alf jessup]

So sad a couple of our locals have lost their lives in this accident

 

But unfortunately something has gone wrong and they have paid the ultimate price

 

Much better chance of surviving if you fly the aircraft as far in to the accident as you can but to do that you need airspeed

 

Looking more like in this case that airspeed was lacking which is not entirely the aircrafts fault

 

Pilot incapacitation may have played a part as Terry was quite experienced with quite a few hours under his belt but in highnsight experience has been the undoing of many a pilot through complacency

 

I am hoping this is not the case with this accident

 

Condolences to family and friends

 

Alf

 

 

[Yenn]

I thought that the folding of RV fuselages was the tail pivoting up and forcing the pilots head forward, rather than the panel coming back at the pilot. It is a well known defect, but the fix may be far more of a problem than fixing warrants. If you know of a fault in any design, it is possible to make a fix, but not necessarily sensible. As always it is preferab;e to fly the plane as far into the crash as possible. Easy to say, but until you try it you don't know how you will go.

 

 

[Oscar]

For those who wish to increase their knowledge of flying a Vans RV6 in difficult situations and thus increase their safety, may I sincerely recommend: http://www.sdsefi.com/air44.htm This is a first-hand report on a deadstick landing (crash) coming from a person who is intensively involved with modifying (and air-racing) Vans RV6s.

 

For those who wish to pick an argument, then take it up with the author of that article.

 

 

[metalman]

Sounds like any aircraft, set best glide, and don't try to stretch it, there's not an fixed wing aircraft that will glide without airspeed, I've read that account before and if I'm missing something please enlighten me. All aircraft behave differently with an engine out, my aircraft will just make the field from base, the Tigermoth I occasionally fly glides like a house brick, so does a Pitts I'm told, I've done glide approaches in an RV6 , I've also done an dead stick in a tecnam and a eurofox,,,,,and in every single aircraft if I'd let any of them get slow I'm in trouble,,,in the article the pilot mentions not trying to stretch the glide, good advice for everything from a thruster to an A380 ,,,so I hope this doesn't sound like an argument but if you've actually flown an RV6 and experienced any adverse behaviour then please post it for all of us to learn from , but if your basing this on two accidents where the pilots seemed to stall the plane at height ,then hold the stick hard back till it all stopped suddenly ,it's called ground aversion , then it's the same behaviour that's been killing pilots for decades,,,,,,,,give it a rest or come up with something that is based on more than an opinion founded on two accidents from a fleet of several thousand.

 

 

[Dafydd Llewellyn]

I thought that the folding of RV fuselages was the tail pivoting up and forcing the pilots head forward, rather than the panel coming back at the pilot. It is a well known defect, but the fix may be far more of a problem than fixing warrants. If you know of a fault in any design, it is possible to make a fix, but not necessarily sensible. As always it is preferab;e to fly the plane as far into the crash as possible. Easy to say, but until you try it you don't know how you will go.

Pretty much a case of the front of the fuselage stopping, and the rear fuselage and the pilot colliding with the instrument panel. The rear fuselage pivots up and over, until the turtle deck behind the cockpit, hits the windscreen arch. In the process, it lets the shoulder harness go slack, so the occupants' upper body naturally is allowed to fly forward, and the occupants' heads are likely to be caught between the rear fuselage at the extremety of its folding, and the instrument panel. The loss in shoulder strap tension allows the lap strap to slacken, so the lower body also is not restrained from colliding violently with the control stick.

All this takes a split second - then the rear fuselage flops back down and looks deceptively normal - but one can easily lift it up to the fully-folded condition, because its strength has been completely destroyed.

 

This overall pattern of impact failure is, I would consider, by no means unique to the RV 6; as MM has observed, most metal canopy-type fuselages can be expected to behave pretty much like this, unless they have strong upper longerons as cockpit sills, that have been designed to have a high buckling strength. The very tight weight limits for recreational aircraft are likely to cause designers to omit the additional material for that, unless the design requirements force their competitors to do so too.

 

Given strong cockpit sills, it would be preferable to anchor the shoulder harnesses to strong structure as close as possible to the back of the cockpit, rather than far back in the tailcone.

 

Composite aircraft of similar configuration, in a similar type of impact - from what I have seen of them - shatter rather than buckling. There is little to choose between them. Occupant survival depends on having a non-deforming cockpit structure; and you simply do not find that in canopy-style fuselages, in aircraft of this general class.

 

 

[Guest extralite]

Thanks for posting that article Oscar. Proud owner of an rv7 which is an absolute delight to fly. It is so direct. Rv7 has slightly lower wing loading then the 6 I believe, but the reminder of how high wing loaded ac soak energy in banked turns with engine out was a good reminder. I have practised lots of engine outs with idle power, prop in fine'surprised that range is reduced so much with engine out. Might do some practicing aiming to arrive couple hundred feet high over threshold.

 

 

[dutchroll]

Generally a suitable field for gliding a Pitts into must be under the wingtip. Having said that, mine has a markedly different glide performance depending on the propeller blade angle. Fine pitch will result in > 3000ft/min rod. Coarse pitch about half that. With a real engine failure it'll go to coarse pitch anyway due to blade counterweights, but if you have oil pressure, it'll go to fine!

 

 

[Dafydd Llewellyn]

Would the person who put the "optimistic" comment on my Post # 36, please be so kind as to enlarge on that comment?

 

 

[DCM]

Would the person who put the "optimistic" comment on my Post # 36, please be so kind as to enlarge on that comment?

Sorry big thumbs on an I pad Don't know how to remove it

David

 

Just realized I could undo it

 

 

[metalman]

Sorry big thumbs on an I pad Don't know how to remove itDavid

Just realized I could undo it

Busted!!!:-)

 

 

[Dafydd Llewellyn]

Sorry big thumbs on an I pad Don't know how to remove itDavid

Just realized I could undo it

Thanks - (I'm quite familiar with big thumbs!) - but it had me wondering a bit, because asking for a non-deforming cockpit does sound a bit optimistic, I suppose - and indeed it does present quite an engineering challenge. However, it has become a requirement for new GA aircraft, if somewhat indirectly, by virtue of FAR 23.562, which was introduced in amendment 36 of FAR 23, around 1988; it was originally a requirement for dynamic seat testing, but if you read the fine print of how that test is required to be done, it involves not only impact testing the seat, but the entire cockpit structure, and ensuring the pilot's head does not impact anything hard. It's now more appropriately titled "Emergency landing dynamic conditions". The Whitney Boomerang was required to pass this test, and it did.

I think this topic merits a new thread.

 

 

[Oscar]

Thanks for posting that article Oscar. Proud owner of an rv7 which is an absolute delight to fly. It is so direct. Rv7 has slightly lower wing loading then the 6 I believe, but the reminder of how high wing loaded ac soak energy in banked turns with engine out was a good reminder. I have practised lots of engine outs with idle power, prop in fine'surprised that range is reduced so much with engine out. Might do some practicing aiming to arrive couple hundred feet high over threshold.

You are most welcome, if it has been of use to even one person then it was worth posting, I believe.

I have no idea of what changes there are between the RV7 and the RV6, but the 7 certainly seems to be a fine and safe aircraft. I don't follow VANs aircraft other than as a casual reader, but I certainly don't recall any questioning of their safety or flight behaviour at all.

 

 

[motzartmerv]

Rv6's and 7's are fantastic little aeroplanes. And with the RPL now, a very viable option for some of us. The thing to consider is that they are NOT light and fluffy designs. They are designed for speed and manoeuvrability, to give the classic RV grin! They will bite harder then a sportstar or a Jabiru if flown "off spec".

 

The last one I flew cruised ver comfortably at 165 IAS and was certainly a "lively" feeling aeroplane.

 

 

[Old Koreelah]

...asking for a non-deforming cockpit does sound a bit optimistic, I suppose - and indeed it does present quite an engineering challenge...I think this topic merits a new thread.

Agreed, Dafydd. I doubled the spruce around my shoulders and added aluminium angle and CM steel canopy hoops.

I'm told wooden aeroplanes splinter when pranged, so I lined my Jodel cockpit with thin ply to add strength and contain breaking spruce timbers. Makes me feel safer, but I'd rather not have a real test.

 

 

[turboplanner]

What is the outer skin of the cockpit?

 

 

[metalman]

What is the outer skin of the cockpit?

The bit that separates the pilot from the air outside,,,,

 

 

[turboplanner]

You studying in the aerogeek academy?

 

I'm looking at the possibility of some bonding to create a structural panel; let's say the outer skin is aluminium, do you use an adhesive that would bond the timber core to the inner and outer skins, creating a much stronger structure?

 

 

[Oscar]

It's the one on the outside of a double-skinned panel, Turbs.

 

 

[turboplanner]

Yes, I know, I was looking for the material the outer skin is made from.

 

 

[M61A1]

Yes, I know, I was looking for the material the outer skin is made from.

If you are asking about a Jodel, it will be wood, plywood, I think.