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theres an interesting bit of info in that report,

 

The unbroken blade and metal spinner that covered the propeller hub exhibited no evidence of rotational scratch marks or power at impact.

yet the engine

 

examination under the supervision of the Australian Transport Safety Bureau (ATSB). No evidence was found to suggest abnormal engine operation prior to the impact with terrain

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I wonder why the report refers to a "non standard approach which included an orbit"Whats "non standard" about orbiting over the airfield to determine wind etc?

Looked like a standard mid field crosswind join to me? Doesnt get any more "standard then that?

Mudgee has right hand circuits on 22 and 16 maybe something to do with it.

 

 

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Local weather report may help. Humidity/ dew point for the day was? No evidence as to why engine failed to respond....... anyone see where i am going with this?

 

 

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According to Wolfram Alpha, the humidity at the time at Mudgee may have been somewhere between 50-60%, and the temp around 20 C. I guess that makes carb ice on descent a possibility.

 

WolframAlpha--weather_in_mudgee_on_14_september_2014--2014-11-04_0253.gif.c43a47c7e375cdd8512fbcb47e59da10.gif

 

 

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Y'know, looking at the photo from the preliminary report, you'd really expect people to walk away from an aircraft with that amount of damage. Why didn't they? I can guess, but surely that question needs to be answered . . .

Probably pancaked in and they weren't exactly young, it's not the fall that kills you it's the sudden stop at the end that does all the damage.

 

Alf

 

 

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I agree; but it won't help if the engine dies at 50 feet and you have to get across a six-lane road and a ten foot high cyclone wire fence, to reach the school playing field on the other side. That's what caught the RV 3 pilot.

If you accelerate any model of RV to at least Vy below 50ft, then you'll have some manoeuvring ability. I never allow either my 9A or 6 to rise above the 50ft 'barrier' until they have achieved 90 KIAS and continuing to accelerate. On short/soft/rough strips you can still accelerate to well past TOSS provided you retract the take-off flap before Vfe, (78-85). RVs don't cool their engines at all well below 80 KIAS, and a higher speed 'cruise/climb' of 110-120 KIAS is kind to your engine. In the fixed pitch models, it also improves propeller efficiency and ROC.

 

Now, as to the issues of RV handling on approach. As an instructor, doing BFR's, I've experienced 2 separate instances of having an RV6 stalled on the turn base to final. Reason : pilot distracted at un familiar strip, tailwind component on base, idle power, and pulls full flap on base, 70 IAS, then rolls into 45o AOB with some loading of the wings to get back onto final. Lots of loud airframe bumps - and down goes the nose. Luckily, the pilots hadn't made the superbad mistake of using excessive left rudder and inducing a skidding turn...otherwise we'd have spun 'under' at 500 ft agl and there's iffy recovery from that. The RV6 is all too easy to overbank, and doing this during low speed approaches is really tempting fate. I usually teach power on into any steeper turns, and/or, lowering the nose considerably. With an RV6 at idle power and full flap, to hold 65 - 70 KIAS in a base to final turn - the nose needs to be stuffed down!!

 

There's some comment around that full flap shouldn't be selected in the 6 series until very late in a glide approach. That gives you some range in your glide, and it also ensures you are less likely to underestimate the ROD. The manual flaps can be deployed in an instant once the aircraft attains the threshold - it's rarely going to float from this. This adds another activity to perhaps a very stressed pilot - which some can and some can't handle. If you are not holding a good 60-65 KIAS on the 6 at the beginning of rounding out from a glide approach - then you'd better be able to judge your height to perfection or you'll arrive with a lot of vertical component.

 

The 9A, on the other hand, is an absolute pussycat. It actually needs to be flown at a lower IAS than 60 in order to achieve a 500fpm ROD. With a Vso of 43 KIAS - the 9A gives you plenty of time to roundout and holdoff. In fact, if you don't use aerodynamic drag - you'll never land!

 

[ I have been test flying, and instructing in RV4, 6, 6A, 7, 7A, 8, 8A, 9, 9A, & 10 since 1998, and owned a 6 and 9A since 2001 and 2008 resp]

 

 

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The 9A, on the other hand, is an absolute pussycat. It actually needs to be flown at a lower IAS than 60 in order to achieve a 500fpm ROD. With a Vso of 43 KIAS - the 9A gives you plenty of time to roundout and holdoff. In fact, if you don't use aerodynamic drag - you'll never land!

Poteroo, As an owner of an RV9A I can agree 100% in what you say re landing the 9A. I have flown the 6's and agree they can be a little more twitchy. The air speed/s certainly need to watched closely.

Cheers Mike

 

 

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  • 1 year later...

Yet another RV6 kills its occupants by structural failure of the cockpit.

 

Let's get this straight: the INCIDENT was initiated (probably) by carburettor icing causing an engine stoppage.

 

The ACCIDENT was caused by aerodynamic problems related to weight and airspeed leading to loss of control. (The ATSB report is deficient in not recognising the typical RV6 loss of elevator authority at lower speeds in the case of no prop wash, though that is more pronounced as an inability to round-out rather than any inability to lower the nose to prevent a stall occurring).

 

The FATAL INJURIES to the occupants resulted from deformation of the cockpit structure.

 

 

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I have different thoughts after reading the report

 

The ACCIDENT was caused by aerodynamic problems related to weight and airspeed leading to loss of control.

the pilot put the aeroplane in a situation such that loss of control was likely.image.jpeg.796f8413b458bf0bcd72e4d7021d3cd1.jpeg

 

Yet another RV6 kills its occupants by structural failure of the cockpit. .... The FATAL INJURIES to the occupants resulted from deformation of the cockpit structure.

analysis shows that it would've been fatal regardless of that deformationimage.jpeg.cb9f737aa18deb341199be4180319b0c.jpeg

 

...... was initiated (probably) by carburettor icing causing an engine stoppage.

and they might've had longer lives if not for that.
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All the holes lined up that day, it was from a multitude of things by the looks of it

 

An uncontrolled fall from 500 ft will do it most times in any aircraft, I'm with you DJP, it didn't matter what it was

 

Very sad loss as they were a lovely couple

 

 

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DJP - with respect, I believe the ATSB report stated that the cockpit buckling meant that 'the occupants were no longer adequately restrained.' The comment you have quoted is: 'together with the effect of the impact forces' etc. the accident was considered not survivable.

 

I read this as: 'due to the cockpit sides buckling, the occupants were not restrained from impacting the deformed structure.'

 

I guess we won't know until the coronial report, whether the cause of death was fatal crushing of organs etc. due to deceleration forces fed through the restraint harnesses, or blunt force trauma of impact of (usually) the cranium into a structural component. Let's both hold judgement on that.

 

On the aerodynamic contention: the ATSB report suggests that it was right on the thin edge of uncontrollability - but on the correct side of that edge. You know that the POH figures are derived with a margin for safety - but they are derived in 'normal' conditions. The RV6 has a well-known problem with elevator authority in an engine-out situation.

 

 

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With a GPS derived airspeed of 4kts below the correct approach speed I would assume that the headwind would have lifte the airspeed to above the approach speed required. I know with a good headwind, my GPS speed on approach is frighteningly low. That is why we shouldn't use GPS for speed control unless we are sure of the actual wind speed.

 

 

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With a GPS derived airspeed of 4kts below the correct approach speed I would assume that the headwind would have lifte the airspeed to above the approach speed required. I know with a good headwind, my GPS speed on approach is frighteningly low. That is why we shouldn't use GPS for speed control unless we are sure of the actual wind speed.

You've opened a can of worms here Yenn ...

 

 

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With a GPS derived airspeed of 4kts below the correct approach speed I would assume that the headwind would have lifte the airspeed to above the approach speed required. I know with a good headwind, my GPS speed on approach is frighteningly low. That is why we shouldn't use GPS for speed control unless we are sure of the actual wind speed.

I would have assumed that the atsb would take into account the current winds at the time of the incident and have allowed for that in their findings.

 

 

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The RV6 has a well-known problem with elevator authority in an engine-out situation

When I did the Phase 1 flying on my RV6 in 2001, the Vso = 48 KIAS, which then gave me a calculated approach speed of 48 KIAS x 1.3 = 63 KIAS, ie, exactly the same as the Mudgee RV6. What I found in the flight testing of this RV6, and several others, was that the 'break' is sudden. ( I always used some power x 65 KIAS for general landings). It's even more so when you load up the wing in a turn of even 30 degrees. At 48 degrees it would have been very sharp.

 

So, if you allow your RV6 to enter a steep turn during a descent - add power to give you elevator command. In a gliding turn - use 65-70 KIAS and keep turns to 30 degrees. There is no need to be making a 1770 fpm descent rate, in a 48 degree turn in any circumstances - let alone turning onto final.

 

The RV6 is a great little performer - it just needs to be flown with due care and regard to the laws of aerodynamics.

 

happy days,

 

 

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