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Mudgee


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Two of the most gentle and kind people you could ever meet. Plus an experienced, fastidious aircraft builder and pilot. These folks are a great loss to our flying community. Thoughts and prayers for them and their family. Laurie.

 

 

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interesting to note in one report i have read, is that both occupants, were not found inside the aircraft, looks like they survived the crash, exited the aircraft, then succumbed to injuries.. or quite possible the pilot and passenger suffered heart attacks as shock set in, or the crash was caused by the pilot suffering something that incapacitated him/her, and the passenger suffering a heart attack from shock after the event...

 

all purely speculation based on something i read that might or might not be factual... im sure the facts will come out shortly...

 

 

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Yeah one of my questions is regarding the survivability given the pretty intact and upright state of the aircraft, and that being on approach it was presumably fairly low speed. I find that puzzling.

The RV6 has two known and documented problems that MAY be relevant.

 

The first, is a known structural problem with cockpit strength, that in a crash allows the sides of the cockpit to deflect and cause the whole aircraft to fold as if hinged around the mainspar and bring the top of the panel back and crush the occupant's foreheads. Typically, once the 'fold' has happened, the aircraft flops back into a fairly normal-looking attitude; this effect was found under forensic examination to be the answer to otherwise inexplicable death. An EO was developed (in Australia) to assist in strengthening the cockpit, but even if this had been applied to this aircraft it is probable that the apparent descent angle would not have been survivable. An RV6 is not a particularly crash-worthy aircraft, and the statistics support this contention. It is nowhere near as potentially lethal as say a Lancair 240/260 or a Cirrus, but equally it is far below mainstream GA aircraft or even any Jabiru for crash survivability.

 

The second, is a lack of elevator authority in an engine-out situation that will not even allow a normal flare if under about 55 kts - the aircraft will just fly into the ground, no matter where the stick is being held.. Recovery from a low-speed stall would be absolutely impossible in an engine-out situation on the height reported.

 

Please let's not get into 'issues' here: two apparently fine, decent, loved and respected people have died from an unfortunate situation. Unlikely to have been pilot error, but due to fundamental characteristics of a particular aircraft.

 

 

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interesting to note in one report i have read, is that both occupants, were not found inside the aircraft, looks like they survived the crash, exited the aircraft, then succumbed to injuries.. or quite possible the pilot and passenger suffered heart attacks as shock set in, or the crash was caused by the pilot suffering something that incapacitated him/her, and the passenger suffering a heart attack from shock after the event... all purely speculation based on something i read that might or might not be factual... im sure the facts will come out shortly...

The reports I have seen indicate quite positively that the pilot was inside the cockpit.

 

 

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The RV6 has two known and documented problems that MAY be relevant.The first, is a known structural problem with cockpit strength, that in a crash allows the sides of the cockpit to deflect and cause the whole aircraft to fold as if hinged around the mainspar and bring the top of the panel back and crush the occupant's foreheads. Typically, once the 'fold' has happened, the aircraft flops back into a fairly normal-looking attitude; this effect was found under forensic examination to be the answer to otherwise inexplicable death. An EO was developed (in Australia) to assist in strengthening the cockpit, but even if this had been applied to this aircraft it is probable that the apparent descent angle would not have been survivable. An RV6 is not a particularly crash-worthy aircraft, and the statistics support this contention. It is nowhere near as potentially lethal as say a Lancair 240/260 or a Cirrus, but equally it is far below mainstream GA aircraft or even any Jabiru for crash survivability.

 

The second, is a lack of elevator authority in an engine-out situation that will not even allow a normal flare if under about 55 kts - the aircraft will just fly into the ground, no matter where the stick is being held.. Recovery from a low-speed stall would be absolutely impossible in an engine-out situation on the height reported.

 

Please let's not get into 'issues' here: two apparently fine, decent, loved and respected people have died from an unfortunate situation. Unlikely to have been pilot error, but due to fundamental characteristics of a particular aircraft.

So unfounded speculation begins, un f**king believable !

 

 

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The existence of an EO for strengthening the cockpit is not 'unfounded speculation', nor is the lack of elevator authority in the case of an engine-out. The 'folding' situation has been proven. If you do not wish to acknowledge relevant information, fine by me, but don't deny that information to people whose lives might be saved by knowing it.

 

 

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The existence of an EO for strengthening the cockpit is not 'unfounded speculation', nor is the lack of elevator authority in the case of an engine-out. The 'folding' situation has been proven. If you do not wish to acknowledge relevant information, fine by me, but don't deny that information to people whose lives might be saved by knowing it.

I think you are referring to the cockpit sill reinforcement kits that were being produced by Graham Moodie (I hope I have that right) after he saw parts of a report that my son wrote to the QLD branch of ATSB, after he and I examined a wreck of an RV3 and an RV6 (both fatal) at Toowoomba, with ATSB's permission, at least a decade ago. (We were looking for data relating to lower leg injury, in a quite different context, but the fuselage collapse mode was something we noticed in the process). I could not approve an EO under CAR 35 because the aircraft is experimental, and therefore does not comply with any normal design standard - so the wording of CAR 35(2) is impossible to meet; however I saw what Graham was doing, and it looked to me to be helpful. Both those aircraft folded as you describe due to outward buckling of the cockpit sill, which completely nullifies the effect of the safety harness; the turtle deck behind the cockpit had paint marking from the windscreen arch in both of them; the fuselage had acted as a giant nut-cracker in fact.

I would be interested to know whether the Mudgee aircraft had this mod. installed. However the presence or otherwise of the reinforcement has no bearing on the cause of the accident.

 

 

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The existence of an EO for strengthening the cockpit is not 'unfounded speculation', nor is the lack of elevator authority in the case of an engine-out. The 'folding' situation has been proven. If you do not wish to acknowledge relevant information, fine by me, but don't deny that information to people whose lives might be saved by knowing it.

Really want to get into this then, the cockpit is not much different to lots of low wing lighties, there is an issue with how the seat belts are arranged , but if you hit the ground hard in any aircraft you'll get hurt, we just aren't able to handle the G's involved.

As for the elevator story, the source of that has never stalled an RV , plenty of others have ,and they stall like any aircraft that is well designed to be sporty, I've stalled a few without any odd behaviour. A good mate would be one of the most knowledgeable pilots in Oz regarding the RV aircraft, I've discussed this with him, he's stalled them all ,engine running ,off ,turning, S&L and they recover normally. Of course if you were to fly ( or try to) any aircraft around at three knots above the stall you would find it quite a handful, 55knots? They stop flying at 50-52kias clean (49 dirty) ,,,a high decent rate would be expected, recovery is simply a matter of reducing the AoA and it flies again,,,,,just like most aircraft,,,and just like most aircraft ,if you hold the stick back the ground will arrive very quickly,,,,I AM NOT saying this is the case here, I along with most here have no idea what has happened , and would again say the blabbering theories is not only disrespectful to the deceased ,but painful for relatives and friends,

 

 

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Ah, my mistake, I thought the fuselage sill reinforcements came under an EO, but the intricacies of the Ex category elude me. I agree - it could not have been a cause of the accident - but MAY have been a factor in the result.

 

 

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That's very interesting. As per my previous post (and not wanting to detract from the tragedy of the situation), survivability aspects struck me as very puzzling given the footage I saw.

 

As it happens, I was actually flying over Mudgee enroute from Cessnock to Narromine when all this was unfolding and heard a lot of the relevant radio traffic on area freq. Upon my return I was pondering my own situation of being strapped in by a Hooker aerobatic harness into a carbon fibre seat to the point of barely being able to move, knowing that the chrome-moly tig welded tubular airframe of my aircraft has been shown to be quite survivable to well over 10g vertical deceleration (albeit with significant back injuries in the case of the accident I'm thinking of).

 

The actual cause of the accident is of course the other question I'm pondering and I won't publicly speculate. There are simply too many possibilities at this stage. I'm confident they'll be able to quickly narrow them down however.

 

 

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Well, both the aircraft we examined had indentation of the box-shaped recess that the control stick works in - the rear corner of it acts as an elevator travel stop, for want of anything explicitly for that purpose; it was obvious that the pilot had pulled extremely hard - which we took to indicate that he had run out of elevator to lift the nose.

 

There may or may not be a difference between engine idling and propeller not turning in regard to elevator power in the flare, especially if the speed gets a bit low. I've not flown an RV, though I've been invited to; I do not fly other people's aeroplanes - especially experimental ones - for fun or for the pleasure of performing unpaid research; the flight testing that I do is a serious part of earning my living. So I have no first-hand knowledge of this; but the fact that the pilot had evidently pulled back with all his strength; and had then been thrown forward onto the stick, despite his safety harness, sufficiently hard to fracture his pelvis (in one case) and his hip (in the other) - and in the process to partially fracture the stick in forward bending - spoke very clearly to me. "Stretching the glide" in an RV 6 with a stopped engine seems definitely contra-indicated; putting it on the ground and plowing through the fence seems a better risk.

 

It was obvious that the RV3 had hit the ground at about 15 degrees nose-down; and a front corner of the fuselage gouged a quantity of dirt out of the ground, after which the wreckage bounced and hit the ground again about fifty feet further on. The severity of the impact deceleration can be roughly estimated from the mass of dirt that was fired off by the aircraft as it bounced - and it should have been on the borderline of survivability, had the buckling of the fuselage not nullified the safety harness, and then crushed the pilot's skull.

 

This sort of collapse has been extensively investigated by OSTIV for glider cockpits; and any canopy-type aircraft is very likely to have its principal fuselage weakness in the cockpit area. So yes, if you hit hard enough, it will kill you. But "hard enough" is evidently surprisingly low, in some cases.

 

I repeat, this may have no relevance whatever to the Mudgee accident.

 

 

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