Oscar

Talk about your short answer , long answer.Is there a name for that ?

Sure is - it's called 'amortised operating cost'. If you buy a c/f fantastic and fly it say 100 hours/year, the fact that it cruises at 10 kts faster (in good conditions..) saves you some time per major trip. A typical Jab, cruising at say 95 kts will cover 380 nm in a four hour trip. Be generous, round that out to 400 nm, because Jabs have very decent gust penetration and Vb and and so can maintain cruise speed until it gets very rough.

 

A c/f vonderkinder cruising at - let's say - 110 kts, will travel 440 nm in a four-hour flight; let's round that out to 465, for the same flight conditions. That's 65 nm further.

 

For your 100 hours annually, the c/f vunderkinder will travel 1625 nm further.

 

Can people provide their annual hull insurance costs for - let's say - a J160 vs, say, a Carbon Sting? It'd be interesting to see if the Sting costs are less than $1625 more than a J160.

 

 

Running out of fuel at 7:30 am?

I'm not aware of any 'fuel content at AEST rating' - perhaps you could elucidate us all as to why you can't run out of fuel before business hours?

 

Or is it just possible that these guys took off without adding fuel because the bowser / fuel truck wasn't operating when they took off?

 

 

I've seen worse , and there flying now ,The windscreen not broken

Starboard wing attachments pulled out; even that's repairable but a new wing would be a better option. Grafting on a new tailcone end - ( you'd even be able to extract the horizontal stabiliser and re-use it) or even putting the somewhat surgically-removed one is no biggie if you make up a jig to get the location correct. The repair techniques do not require sophisticated equipment and can easily be validated by post-repair ultimate load testing - and that can be done using remarkably simple equipment and some care - provided you know what you have to do..

 

One of the major advantages of Jabiru construction is that it uses a composite lay-up that is extremely damage tolerant and also is repairable to 'as good as new' without requiring autoclaves etc. By comparison, a 'c/f construction' aircraft is a bloody nightmare to both fully inspect for damage without laboratory-class equipment and impossible to repair without very high-tech facilities. Metal construction is inspectable and repairable, but you can't 'cut and shut' all that easily, if major load-carrying members are affected.

 

Jabs are a bit like Toyota Hilux's - not the most sophisticated but you can't break them irretrievably with less than a seismic event. If you buy Porsche performance, don't be surprised if you have Porsche-sized bills for repairs - and Porsche-sized insurance costs.

 

 

That was some seriously good decision-making and flying, I reckon - I just measured that entire field on Google Earth and it's a bit over 450 metres at the longest axis with mature trees all around, lots of power lines, and just nowhere else to go.

 

 

No, no - you're overlocking the essential point that people should strive to pleats everybody...

 

 

Nice to see polite exchanges without some of the needling that goes on here too often. Of course, that's what should be a guiding principle of a thread.

 

 

Good heavens - a realistic engine that actually exists. However did they manage to get that far without some unauthenticable photos and an endless supply of : 'and next week, I'll have some wonderful news' posts?

 

Jeez, you just can't trust some people. They just go out and do it - the bastards.

 

 

I think we have already established that this is NOT a 'Jabiru' mandated regulation but one applicable to registration classes of aircraft. If you have a certificated engine (and your registration status and operational approvals is predicated on this), it appears that you will have to abide by the same restrictions. I can't see a 24-reg aircraft, no matter what it is powered by, being allowed to be maintained by anybody other than an 'authorised' person.

 

 

A major, major problem is that the aircraft information that RAA holds is not properly databased with appropriate field-level information that allows selection of information relevant to a specific aircraft to be identified, and the registered owner to be notified by means of the registered communication channel (email address, postal address).

 

By way of example: If a SB were to be issued for a 'Godwot Gadfly', the RAA database should allow the Tech. Manager to promulgate the A/D automatically, with the system picking up all registered owners of Godwot Gadflys and automatically sending the A/D by the nominated means for notification. At the moment, such promulgation is only possible by either: broadcast through the RAA website, or an RAA employee going through all the aircraft registrations to discover who owns a Godwot Gadfly and sending them a notice - having first also accessed their membership details to find their appropriate mechanism for notification.

 

The RAA administrative system is about 1995 vintage (to be generous).

 

 

Nice to hear a good report! Out-of-tolerance heat is the absolute enemy of Jab. engines, and the research that CAMit is currently undertaking is showing up linkages between heat-related problems that have 'traditionally' - for want of a better term - usually been ascribed to component / manufacturing 'defects'. There is a very real possibility that out of the work being undertaken, we will all get a considerable advance in the understanding of the whole cooling 'chain', or perhaps 'system' is a better word, can be made to work - and some urban myths about effective cooling system design may well be laid to rest (not to mention some of the wilder postulations about design and materials of construction that are so far wide of the truth that they should be put into the 'third shooter on the grassy knoll' department).

 

 

Hi Oscar, I hear what you're saying, but i feel that most humans have self preservation and nearly all the pilots I know including me, will ask for advice for things that we don't know. My specialty is airframes and jet engines, not piston engines. For that type of work, apart from the basic stuff ( oil, spark plug changes ect) I will seek a L1 /l2 with the qualifications and who know that kind of stuff.

Dazza - you have the invaluable knowledge of what can go wrong, so you temper your work accordingly. Many do not. To quote my favorite author, Terry Pratchett: '(XX) had an acute sense of his own inadequacy - an affliction that besets altogether too few people..'

 

 

Horses for courses, Dazza. We all know people who have 'lover's hands' but persist on working on things they should not. Heck, we have a regular contributor in here who is an L2 but apparently doesn't know the use of Belleville washers from Blue-tack for propellor retention. I can't see the objection to having a basic competence course being a requirement; it's blanket rejection of disparate competence that is surely the issue?

 

 

Given human nature, it may not be entirely adequate protection to just provide the instructor with the risk analysis rating.

 

This is without doubt suggesting that the regulatory authorities would be venturing into territory more concerned with behaviour rather than matters of safety per se, but I can forsee the situation where an instructor, faced with a request from a friend for a BFR (or for instruction, for that matter), would consider that refusing that request on the grounds of the risk analysis rating is tantamount to saying that they don't trust the competence of the individual. (Same goes for people invited to 'come fly with me', of course.)

 

This is a hugely delicate area. Simplistically, it could be argued that a regulatory authority (such as RAA) could apply operational limits on the aircraft dependent on the risk analysis that precludes training, review, even carrying passengers deemed to be not competent to understand the implications of the stated risk involved. Pretty much all of that actually already exists in the requirements for flying off hours after construction etc., and perhaps all that is required is some strengthening of those requirements to extend/reinforce the 'restrictions' for aircraft that do not achieve a minimum level of 'risk' rating.

 

Some people will regard such a move as 'more of the nanny state' mentality rearing its ugly head. They have a point. It is in practical terms impossible to legislate / regulate for the disparate situations of people being competent to judge risk, because there are many factors that shade the assessment of risk. I have no personal knowledge of either of the people involved in this terrible accident, but from what has been stated, I would assume that Grahame White had every reason to be confident about the capability of the aircraft into which he stepped and equally that Ralph Buchanan would not have allowed that flight to commence if he had any misgivings about its airworthiness. We are not talking about cowboy mentality here, these were serious, experienced, cautious and conscientious people.

 

When one considers the equation of 'freedom of the individual to accept risk' vs. 'nanny-state regulation', what is frequently overlooked is the flow-on effects of consequences. If I choose to build an experimental aircraft using Molt Taylor's resin-impregnated cardboard monocoque construction technique, I would certainly expect to be allowed to fly it - on the basis that 'it's my neck, not yours'. I think most RAA people would support me on that basic philosophy. However: if that structure fails and I crash into a pre-school and kill 20 children as a result, you can guarantee that the public reaction will affect every RAA owner's operation in the future.

 

So the balancing act here is not just between the individual's right to accept risk but an assessment of the social consequences. I suspect that RAA needs to be conservative in its application of regulations in order to protect the majority of its members' 'freedoms'.

 

 

Yep, it certainly needs clarification; for LSA aircraft, it's the manufacturer's call, I suspect (e.g. J160D's, 230D's etc.) and for 19-reg aircraft that have their operational area allowed for a certificated engine, quite possibly the same (or likely to soon be so!). But I suspect that Jabiru can't just say: 'let this be so' and it becomes universally applicable to all Jab engines in all circumstances.

 

While I thoroughly understand the frustration many people have with Jabiru's seemingly very one-sided view of engine problems, I do have some sympathy for their position: Jab. engines are absolutely not something to tinker with unless you know what you are doing - and in quite a bit of the work, have the 'special tools' to hand. ( Not everybody has exactly the same opinion of Jabiru's responsiveness, or lack of it, to problems). That said, I for one will be mightily annoyed if I can't do routine minor maintenance: valve checking, plug checking, leak-down testing, head and through-bolt torque checking etc.

 

Perhaps there is a 'half-way house' solution: Jabiru writes a specific 'course syllabus' that RAA then includes in their L1 training. If there is NOT some accommodation of reasonable, trained owner-maintenance available, then Jabiru would, I suggest, be driving people towards the RPL path (owner-maintenance for at least minor, routine servicing is, to me at least, a major plus for RAA membership vs. going the RPL route) - and surely RAA would not want that to be imposed de-facto on a significant slice of their membership!

 

 

While without doubt, Jabiru may wish to have only 'appropriate' people work on their engines, I can't see this as having any more practical effect than reminding people that there are requirements under various regulations that must be met. As a secondary consideration, of course, it provides some strength to consideration - or rejection - of warranty claims, and here I doubt that Jabiru are exactly on their own in that regard, though others may be able to advise whether e.g. Rotax, Lycoming or Continental happily accept just anybody working on their engines in regard to accepting warranty claims either.

 

Jabiru do not make the regulations specifying 'appropriate' people nor are they able to decree who is/is not 'appropriate' under the regulations. You can do - as far as I am aware - an engine maintenance course at Jabiru, but doing that does NOT automatically make you an L2 and able, for instance, to legally do maintenance on a 24-reg aircraft. You may be judged entirely competent at the end of that course but it in no way (as far as I am aware) gives you any rights unless they are recognised by the regulatory authority. Conversely, as far as I know, you can be an L2 (with accepted expertise in engine maintenance, i.e. not restricted by the terms of your L2 accreditation to NOT working on engine maintenance) and legally do maintenance on a 24-reg Jabiru engine without necessarily having done the Jabiru course. I believe that it is entirely RAA's decision as to who is accredited, and for what activities, as an L2.

 

It may well end up that RAA determines that no L2 who has not done a Jabiru engine maintenance course will be 'approved' to work on Jabiru engines - that is a possibility. However, I don't believe that Jabiru's statement constitutes 'the law' here.

 

 

Lycoming and Continental probably feel a bit more confident that their engines will not fail in service when provided normal care. Perhaps Jabiru actually believe their "improper maintenance" theory?

Are you serious? Have you LOOKED at the 'exclusion of liability' clauses attached to ANY Textron communication? If Textron announced 'good morning', there would be three pages of legal qualification ensuring that such a statement was not legally binding and excluded application to [amongst other classes] any carbon-based lifeform ( currently in existence or otherwise) commencing with aardvarks and including up to - but not limited to the boundaries of - zooplankton.

 

 

Well I'd imagine if you hit the water at a high speed, the water entering the fuselage from the front would literally blow the metal off all the rivets on the fuselage because of the huge concussion pressures. From what I saw of the photographs and what was reported; what you see on the photographs would appear understandable.

By blowing up the image of the detached fuselage sheet, it is apparent that the sheet did indeed 'blow-off' past the rivet heads - most of the holes are head-sized and severely dimpled inwards. It certainly looks as if no fault can be suggested for either materials nor construction technique, though obviously that is something that only the investigators would be in a position to determine.

 

This accident has, I think, been received with appropriate horror by everybody - the horror of catastrophic failure of a critical control system in flight, for what now looks as if it may have been caused by something as simple as a single nut becoming unwound and allowing a chain of utterly tragic events to happen. It would be a decent legacy for the two, by all reports, fine and careful aviators if something could be achieved that improves the safety for the rest of us. I believe that RAA is seeking to achieve such an outcome, though that is not going to be an easy path.

 

It seems to me that there is an inevitable tension between the freedom to accept the risk of one's own actions ( including all aspects of owner-building ) inherent in the nature of 19-reg. aircraft regulations and the role of regulators to mandate standards - these two elements pull mostly in opposite directions. It will be impossible to ever achieve a balance that satisfies everybody, but perhaps the risk assessment path offers the best chance: providing guidance to builders, owners and maintainers while not precluding someone from taking a different approach, with (hopefully) knowledge of the severity of the risk being accepted.

 

Just possibly, if the RAA community can be brought together by this accident to at least appreciate that the intention of any moves on this sort are based upon good intentions rather than the imposition of rules/guidelines for their own sake ( aka, by some, as interfering with their freedoms ), improvements can be achieved that will be 'for the common good'.

 

 

Pressure-limiting valves were commonplace in brake systems from around the mid-70's for the rear brakes on cars (my Alfa GTV had one, actuated by a lever from the rear axle) - but I think they only worked to limit incoming pressure, not relax existing pressure that would happen when an engine run-up lifts the tail on a taildragger.

 

 

Brake performance requires a mixture of characteristics. Let's confine our discussion to disc-type brakes, for the sake of both simplicity and relevance to the aircraft most of us fly.

 

As Turbs has unchallengeably identified, for disc brakes, disc diameter is paramount - a simple appreciation of the principle of leverage. But we are constrained by the small size of wheels we use and the problems of u/c leg flex.

 

Yet: racing motorcycle dry clutch packs averaging around 125mm diameter and about 40 mm depth including the spring packs, transmit 200+ horsepower and sustain gear changes at full power often several times in a very few seconds, for an hour or more of repeated use. The technology is there, with selection of the friction materials, to produce vastly better braking capability in a small footprint than most aircraft brakes. Selection of friction materials - both for disc and pad - is important; any old motorcycle rider will remember the moment of sheer terror when first applying the brakes on a Honda with the 'new' stainless discs in the wet.

 

Given that we have with aircraft wheels a small area for the brake, there are a number of other significant parameters.

 

Probably the most important of these parameters is clamping pressure of the pads to the disc. Factors that influence this are: Hydraulic advantage, brake line swelling, and caliper stiffness.

 

Hydraulic advantage is the matching of the master cylinder area and stroke to the caliper piston area and stroke. It's no use limiting the master cylinder stroke if the required stroke exceeds the lever travel - and that is partially a consequence of line swelling and caliper stiffness.

 

Lever travel needs to be greater than the movement required to overcome any pad knock-off effects, line swelling, and caliper stiffness.

 

Pad knock-off is mitigated by floating discs; I suspect very few U/L aircraft brakes feature that.

 

Line swelling is mitigated by the use of braided stainless brake lines: quite standard practice, but is it adopted by the U/L industry?

 

Caliper stiffness.. Anybody who has looked at early Jabiru calipers has, surely, said: 'you HAVE to be joking'. There are VASTLY better alternatives out there: for Kart racing, for one. Top-line motorcycle racing uses 'monoblock' calipers (that cost about the same as the GDP of a medium-size third-world country), but even half-decent calipers are available for small cost.

 

You can NOT have too much braking efficiency. You certainly CAN have too much braking APPLICATION for the circumstances, which lot of people apply in panic situations (hence the development of ABS), but it's a matter of training and ability to reduce the brake application vs. achieving the system limits and it won't do what's needed - which no amount of skill can rectify.

 

 

it seems to me that the master cylinder we have and the leverage available on the brake lever means the pressures available to the callipers is probably below what is really needed, I found that in moving from single to dual the amount of sponginess in the system doubled (and cant be removed with a proper bleed) and under hard prolonged braking the braking affect just fades away even if your biceps are still doing a full arm wrestle on the brake..... where as with the single it didn't fade away, it was just never there to start with......Andy

High performance motorcycles have amazing brakes, but almost without exception they either have as standard or are improved by the use of braided brake lines that don't allow swelling of the lines under pressure.. Those lines allow for the use of better hydraulic advantage between a simple hand-operated master cylinder and up to six piston calipers pushing c/f pads onto (huge - 330mm diameter on the top racing bikes) c/f discs. If you watch the motogp racing, you'll see that the riders mostly use just two fingers to pull a bike travelling at over 300 kph down to around 50 kph at around 1.8g retardation - with the discs ending up glowing almost white-hot.

 

Our brake systems are pretty appallingly crude, because to a degree, they are sort of adequate for task (mostly). They could be seriously improved without adding much weight or ridiculous cost,but that probably won't happen unless there is user demand placed on the industry.

 

 

I'm not convinced you nee "electronic" fuel injection. A plane engine is nothing like a car environment you are not braking accelerating etc. Fairly simple mechanical is fine with manual leaning and flowmeter. Most of the time you are cruising in a barrow range. There would be RPM settings you should avoid there somewhere too. Nev

Nev - it's the fuel availability in the future issue that has me most concerned, with better mixture control second and no icing third on my list, that makes me want to have efi. Perhaps I am overly concerned but what with the Avgas production situation in Australia plus the diminishing number of regional airports (and the airport charges and fuel call-out charges!) I think it very likely that we all are going to find ourselves in the situation of having to fill up with what's available and hope it's OK more frequently - unless we are flying only from/between busy-ish airfields that have the facilities and the fuel turn-over to be able to ensure deliveries of consistently reliable fuel.

 

Jabs. are finicky about what they are fed as we know; but they're not the only engines in the universe that are. Just about all the European 'performance' cars (and the Japanese ones too) run de-tuned versions in Australia because of our known lesser-quality mogas. Even with the ability of the almost ubiquitous efi systems in cars to compensate fairly invisibly to us for differences in batches of fuel, I think we've all experienced instances of 'dud' tankfuls of fuel, and not always from some petrol station way out in the bush. Since we as RAA aviators are really a very, very small batch of users, as we find our available landing sites pushed further from the centres of population, I think our chances of being relegated to the hind tit on the fuel supply cow will only increase.

 

 

 

Are you going to convince ian to work on efi?

Ha - Ian doesn't work on what I tell him, he works on what his own research shows to be important. But efi just HAS to come to aviation on a more general basis, and the difficulties that Rotax are apparently having with their version WILL be sorted and lessons learned will benefit the industry.

 

While other Flying Schools / operators have reported consistent use of Jab. engines going to 800 - 1000 hrs with no problems. The difference is not the engine or the type of operation.

 

 

There's an even more complete set at: http://www.batemansbaypost.com.au/story/2419290/plane-crash-search-for-answers-continues-photos-video/?cs=12#slide=1 , though that has many photos of people and other subjects beyond actual crash wreckage.

 

They're chilling.

 

 

Well, I have to admit that that's a very definite contender! (Personally, I have deep reservations about built-up crankshafts, but I also admit that they rarely fail.) A turbo engine for flying in your area would be nice to have, I'll absolutely concede as well.

 

My own dream of a 'nearly perfect' aircraft for my own sort of intended use would be a J250 with a full-fruit, certificated, efi-equipped CAMit engine, correctly-applied vg's and a panel that includes a permanent iPad with (probably) Oz Runways. Maybe in a few years...

 

And that's venturing into the area of 'what is 'perfect?' - it just HAS to be the best combination - surely - of attributes for the owner's purpose.