Dafydd Llewellyn

Merv, for once, I agree with you.

I've seen several taildraggers stood on their nose on run-up; especially with toe brakes; If the tail starts to lift, people instinctively push themselves backwards with their toes. I'm thinking about the insurance costs, here.

Whilst the tail is up (depending how far up, of course), you normally have quite a bit of lift on the wings - so even at half-pressure, brakes that can skid the wheel under full weight, will give about as much control as you can handle without flat-spotting the tyres, with the tail up. I doubt you'd notice the difference.

Or a misunderstanding - which is the aspect that bothers me.

Picking up from the discussion on brakes in the "another Jabiru engine" thread - Firstly, Turbs is quite right that comparing aircraft brakes to motorcycle brakes is apples and oranges. If you have ever seen an undercarriage drop test, you will understand why brake disc diameters are so limited on aircraft whose undercarriages deflect outwards. And if you look at the Cleveland website, they have some pretty pertinent comments on the use of stainless steel brake discs. The worst aircraft brakes are those that use a brake drum inside the wheel; and in my experience the choice of which is the absolute worst is difficult to choose between the Auster series and the Super Cub; they are both foul, but for entirely different reasons. The least-worst I have encountered are Cleveland, and there are quite a number of clones of that system; but the discs do get hot, and as a consequence are generally prone to corrosion - so you find fancy finishes like "Black Steel" (whatever that is) that aim to improve that situation. The point I'd like to discuss, is the concept of using an anti-locking valve actuated by the weight (or rather, the lack of weight) on the tailwheel of a taildragger, to reduce the number of accidents where somebody drives the propeller into the ground during engine run-up. This is VERY expensive, because it invariably requires an engine bulk strip and possibly a crankshaft replacement. The valve must not altogether prevent braking, but could perhaps reduce the pressure at the calipers by half when the tailwheel is off the ground. Comments?

Dead right, Turbs - but this should be a separate thread. I'd like to canvass views on whether taildraggers should have an anti-locking valve operated by weight on the tailwheel, to prevent overturn - but not on this thread.

I certainly don't imagine there are any sinister intentions. But the grade of pilot licence or whatever one holds is a rather shallow way of indicating knowledge, except in a rather narrow aspect. It's not so much what aviation qualifications one holds, as what one has done with them that counts. What you are looking for, it seems to me, is somewhat akin to the information necessary to qualify an expert witness in court - and that's hardly practical to condense into a footnote under somebody's avatar. If you base it too narrowly, it is likely to give a false impression. If you expand it, it will sound like bragging. To illustrate, the existing tag "aircraft" is ambiguous - do you mean, the aircraft somebody currently owns, or has owned, or currently flies, or has flown? Which of these would be the most informative? Most pilots - especially LAMEs - with any involvement in the industry will have flown many types; whether one owns an aircraft can depend on many factors. I think perhaps one might be able to draw some significance from a study of the third aircraft that a country doctor has owned, but that is of course tempered by his needs and earning capacity. (The first aircraft well-heeled professional people own is generally pretty similar to what they trained on; the second is a "performance" retractable with CS propellers, a twin if the owner is a lawyer or a doctor; the third is generally a fixed-gear single with a CS propeller and good haulage capacity - e.g. a Cherokee six or equivalent). That pattern is one I have often seen - but you can hardly read it over to the demograph of this website, at least as I see it from the posts.

Them's the breaks (brakes?) - I can't speak from experience with Jabiru brakes; however I can do so for Cleveland brakes: My Cherokee 140 had, as do all Pipers except the ones with those execrable expanding tube types, Cleveland brakes; and the brake discs were very prone to corrosion, unless the thing was in daily use. By the time I acquired it, the discs were badly pitted, and it chopped out pads very fast. I replaced the discs with hard chrome plated ones, and the pad wear all but disappeared. The chrome plate was just starting to get a trifle ragged around the edges when I sold the aircraft three years later, but the pads had hardly worn at all.

Its main advantages are (1) it's much easier to get a more uniform mixture distribution (as long as the injectors stay clean and keep working properly); (2) The ability to modify the mixture to compensate for a batch of reduced octane fuel - this is likely to become more important in the future; and (3) it's not so inviting to people to tinker with it. The downsides are: (a) Many more potential failure modes; (b) Needs electrical power; © Needs a purely mechanical "get you home" system. It's MUCH more difficult to certificate than a carburettor system. AND it presents the engine manufacturer with a more difficult liability issue than does a carburettor. So making that leap is no small matter for an aero engine manufacturer, at least for his certificated engines.

I doubt he needs convincing - but that's an exercise for a complete engine certification, methinks. Therefore, rather further down the list.

Quote: " I did my risk analysis and went up . . ." That's precisely what you do every time you get into either an Experimental or a CAO 95.55.1.5 ( -19 registration) aircraft. It is, in fact, one of your freedoms (the right to assume personal risk) as an Australian citizen; recognition of this was the reason the Howard government in 1994 instructed CASA to introduce an American-style Experimental category; and thus why it was introduced in CASR Part 21, in 1998 - I know, because I was involved. So it's not actually something to be sarcastic about; SAAA and AOPA had been fighting for this for decades. However, you cannot assume a risk unless you understand fully the nature of that risk. How completely do you (or for that matter the vast majority of RAA members) actually understand the risk? What do you really know of aircraft safety standards? Or are you what the hillbilly described as "Iggernut"? (Iggernut = doan know an' doan wanna know).

I wonder why anybody imagines this is funny?

Or should you be interested in where they are coming from, in order to decide what weight to give their comments?

Depends on what else is going on at the time; if things are quiet and there's a fatality and there's potentially an airworthiness issue, i.e. something to be learned, I think they may be prepared to look at it; but I understand that hasn't happened in this instance. They usually don't get involved with experimental aircraft, which essentially this is.

Indeed, hindsight is 20/20. One may well ask, where was ICAO on this one. But give it some thought - how does an airline operations office - or ICAO, for that matter - keep track from day to day of where surface-to-air missiles are in the hands of adolescent-mentality militia? Does QANTAS have a link into ASIO ? (and given the past performance of those clowns, would you place any reliance on such a thing?)

Well, it's a question I'd be asking, if I were the investigator and if the rudder is in fact missing. Too many "Ifs". Let's wait & see.

Well, I'm a retired CAR 35 engineer (i.e. professional), a PPL (with CASA test pilot authority) and I'm a member of GFA, flying for pleasure. How do I answer that questionnaire?

Now, why would the rudder be torn off by impact with the water?

Precisely what do you find puzzling? The cause is anybody's guess until the investigation report is published. All we know at this stage is that a very experienced instructor and the pilot undergoing a flight review, were killed, and that there was some unverified mention in the media the something was seen to "fall off the aeroplane". Could have been a bird, could have been a bit of the aircraft, could be somebody's imagination. To find out, you will just have to wait, like the rest of us. However, the aircraft was registered under CAO 95.55.1.5, which means it has the same status as an experimental amateur built aircraft under CASR 21.191(g). This is explained in CASA AC 21.10, which you can find at www.casa.gov.au. Here's a relevant extract from AC 21.10. 8. REGISTRATION AND MARKING 8.1 Prior to application for issue of the experimental certificate, the aircraft must be registered. 8.2 In addition to the nationality and aircraft registration marks, as required by CAR 1998 Part III, the following markings are also required: (a) an aircraft registration identification plate must be attached to an accessible location near an entrance. (b) an aircraft data plate with specific information imprinted on it must be fixed to the aircraft; © the word “EXPERIMENTAL” must be displayed on the aircraft near each entrance (interior or exterior) to the cabin or cockpit in letters not less than 5 cm nor more than 15 cm in height. The letters should be in block capitals of a style that is conspicuous and legible, and easily read by each person entering the aircraft; and (d) for other than single seat aircraft, a warning placard must be displayed in the cabin or cockpit at a location in full view of all passengers, with the wording: “WARNING THIS AIRCRAFT IS NOT REQUIRED TO COMPLY WITH THE SAFETY REGULATIONS FOR STANDARD AIRCRAFT. YOU FLY IN THIS AIRCRAFT AT YOUR OWN RISK”

Well, firstly, no, it's not only relevant to structural failure; would you consider, say, an aileron coming off due to flutter as a structural failure? But would you consider mass-balancing as a valid means of reducing the risk? Would you consider inadequate stick force per G as a structural issue? Or would you consider a reasonable value of stick force per G to be a risk-lowering factor for overloading the wings? Almost all the flying I've done since 1998 has been under an experimental certificate. I'm in the process of setting up a personal aircraft for operation under an experimental certificate. However, in these cases I have had an intimate knowledge of exactly what went into those aircraft and exactly what their design limitations were; and I supervised the weighing and such things as the fuel system ground tests. I'm not afraid of flying an aircraft under an exp. Cert. under those circumstances. But you would not get me into an amateur-designed, amateur built aircraft with a double-barrel shotgun, unless I had that level of knowledge of it. The normal aircraft design standards are minimum standards - and they are written in blood. With an experimental aircraft, you do not have to demonstrate to the steely-eyed representatives of CASA that it complies with those standards - but there's nothing wrong with using the standards as guidance material - in fact, it's downright stupid not to do so. They represent about eighty years of accumulated wisdom, boiled down. I'm putting a motor on a Blanik. That means, I have to put a fuel system, and electrical system, and a powerplant system into it. So I'm using the design standard for powered gliders (JAR 22) as the guidance material. I'm writing a compliance summary as I go. I'll append that to the risk analysis that I must submit under CASA AC 21.10. Maybe it will have some bearing on the operational restrictions CASA will see fit to put on the experimental certificate. A kit manufacturer could well do likewise, and if he does, it could allow an expert panel to express some opinion as to the potential risk level of his kit. It would, in fact, be in his interest to get a favourable risk analysis score. I think the overall effect of something of this sort on the safety standard of 51% rule kits should be obvious.

Well, speaking personally, I find it more constructive to chop a load of firewood, if there's nothing more apposite available. I would say, do not grieve that these men died; rejoice that they lived. Everything that lives must die; that is an inevitable fact. The wonderful thing is to have any existence at all. The statistical chance of being born means we have each won the most incredible lottery. We miss people we have known; and the price is high for those directly involved - but look at it the right way around. Having conducted several accident investigations of fatal crashes myself, I've found it useful to document what definitely did NOT cause the accident. That acts to focus attention on a "short list" of possibilities - and it goes a long way to stopping irresponsible speculation. We do not know whether there was an airworthiness problem or a piloting problem, or something else - but given the experience of the instructor, a piloting problem seems less likely. Hopefully, the investigation will clarify that. However, the classification of the aircraft puts it in the lowest safety category, and the significance of that needs to be recognised. The fundamental point here is, I suggest, that the aircraft was a 50% rule experimental kit aircraft (under RAA 95.55.1.5, but in effect operating under the same philosophy as a VH aircraft under CASR 21.191(g)) . That means, flying in such an aircraft constitutes a voluntary assumption of risk; and since the crash occurred in NSW, it comes under the "hazardous recreational activity" legislative precedents. Both occupants presumably comprehended this. If you look at the appendices to CASA Advisory Circular 21.10, which explains the whole experimental aircraft scene quite comprehensively, you will find a risk analysis there (mainly focussed on the risk involved in the initial test flying). I would like to see that risk analysis extended somewhat so that it could give some indication of the risk according to the merit or otherwise of the aircraft; and that risk analysis score to be displayed on the mandatory notice that is required on all experimental aircraft.

Why are people arguing about a quotation from literature? This is totally inappropriate speculation disguised as an academic argument. Surely the first thing that needs to be done, now the wreckage has been recovered, is to work out what bits (if any) are missing. The forensic study of aircraft wreckage is a rigorous discipline. It may or may not reveal something significant; it's essentially a process of progressive elimination, and very tedious, but until the process is completed, the waffle that has been going on in this thread, beyond expressing people's feelings, is, candidly nauseating and I suggest, irresponsible.

Gliders have dive brakes; most of them are designed to limit the speed to less than the design diving speed (the ones that do this are called "speed limiting" brakes). In one of these, with no gyro instruments, you can open the brakes and take your hands and feet off the controls. Provided the cloud base is high enough, you may come out giddy, but the aircraft will remain in one piece. However, flying gliders within cloud is verboten in Australia, so you should never need to try this. If you try to retain control, in a glider with no gyro instruments, you are very likely to overload the airframe or pull the wings off.

Go and re-read my post #40, especially the fourth paragraph.