Harro

Maybe the attached article throws some light on the circumstances. Crash secret revealed_ minister was at the controls.pdf

The Hudson crash strikes a chord with my family history... my father John Harrison was meant to be on that flight as the photographer from the RAAF Public Relations Directorate. Here is his reference to the incident - with a bit of pre-amble - in his own words (excerpt from a transcript of interview done in 1991 - John Harrison, RAAF Public Relations photographer, interviewed by Daniel Connell for The Keith Murdoch Sound Archive of Australia in the War of 1939-45.) JH: ... Anyway, I'd been there about three weeks when the question came up of the Minister, Jim Fairbairn, making a round Australia trip in the twin-engined Percival Q6 which was owned by the Civil Aviation Department which came under him. And then it became a matter of somebody who'd go with the Minister and I was the one selected to do it, on the round Australia trip with Fairbairn. I was the sole companion. He flew the aeroplane. DC: What sort of aircraft? JH: Percival - named after Edgar Percival - and Australian Percival Q6 - two Gypsy 6s and would carry about six passengers, retractable undercarriage and constant speed air cruise, and by British standards a fairly [worn?] aeroplane at that time. Well anyway, on the trip the Minister flew the aeroplane and I did everything else. DC: It sounds like an enjoyable government assignment. JH: And the Minister made the speeches and flew the aeroplane and I did pretty - everything else, including when we got around to Forrest, halfway between ... END TAPE 1, SIDE A BEGIN TAPE 1, SIDE B Identification: this is side two, tape one, John Harrison. End of identification. DC: If you could just go back a little bit. JH: We overnighted at Forrest. Could not put the aeroplane in a hangar, it had to camp out. I had to get the covers and so on over the engines and the cockpit. And next morning, after heavy frost, get these covers off and I then had to hand swing these Gypsy 6s, which I managed to satisfactorily. We then got into Adelaide and over to Melbourne on 1st August. And then I think it was about 12th or 13th/14th August I met his private secretary in the men's room - I think that's the word for it - of Century House, and Dick Elford, his private secretary, said, 'John, I'm sorry, I've done you out of a trip. I'm going with the boss tomorrow.' Well, that trip 'tomorrow' resulted in the Hudson tragedy at Canberra where three Cabinet Ministers and the Chief of the General Staff - everybody on board - were killed. So that was luck number two for me - I missed that by a whisker. So that was that.... Me: RIP those on board.

Just like to add my two cents worth. I am an engineer, aeronautical at that, with military experience, and also significant construction experience. In my summation of the 9/11 saga, there are far too many inadequately answered questions, often with counter-intuitive outcomes. I can't say for sure what did happen, but I find the official narrative far-from-convincing in many areas. My suggestion is that each does his own research to arrive at conclusions that satisfy the level of one's curiosity. If one person's conclusions differ from another's, it is no reason to resort to name-calling etc. My curiosity is forensic level... based on physical evidence/ physics/ engineering/ material science etc. My heart-felt condolences go out to all those who suffered as a result of the events on '9/11'.

For me, the focus is on safe operations, and if I can learn from another's mistakes, I will. I don't have an 'I told you so' bone in my body. In a past life, I have been involved in enough aircraft crash recoveries that another person's demise certainly holds no fascination for me. The fact that aircraft fly holds fascination for me... not how they crash. I accept that we are all different, and I think it comes down to personality. The fellow aviators I know are a fairly humble lot.

It is particularly disconcerting when experienced pilots come to grief. You have the dubious experience of having witnessed this particular incident, so probably have a better idea of what may have occurred. From my reading of all the previous posts, no one is saying what 'did' happen, only what 'might' have gone so catastrophically wrong in this instance, absent corroborating information. I think I speak for all when I say that no disrespect is intended toward those involved, their families and friends. I am a relatively low-hours 'wannabe' pilot (but I don't hit the keyboard very often :) ), and it concerns me greatly every time I read of yet another light aircraft accident, often with very experienced pilots at the helm. What is it that rears up and bites them on the arse??? Again... and again... and again. Allow me to gain the most benefit from others mistakes by considering at length what 'might' have gone so wrong. Personally I feel that contemplating numerous possible scenarios significantly lessens the chance of my making fatal errors in future. As a side note, I would have refrained from highlighting that line above in bold red type... that is much more likely to be read by anyone perusing this forum, rather than commentary buried within a paragraph in normal type font. I understand the need for sensitivity in posting, but that needs to be balanced with the intent to educate other forumites. I assume the poster in question has some experience with burn injuries, and I now know something I didn't know before. No offence intended, and posted with respect for all.... particularly those numerous experienced 'keyboard wannabe pilot' forum members who contribute so much to this site by sharing their collective, often hard-earned wisdom.

Very sad outcome, whatever the chain of events. One thing that puzzles me... William Creek to Leigh Creek is approximately 150nm; Brumby 610 cruise is approximately 100 knts plus; Flight time would normally be 90 minutes plus departure circuit time of 10 minutes, so 100 minutes all up to overhead Leigh Creek; Estimated time of departure was 4pm (according to news reports); Emergency services alerted at 6:24pm (according to news reports). This indicates a flight time of say 4pm to 6:15pm (around 135 minutes) for a 100 minute flight??? From the above, if all had gone well, with bugger-all margin for error, they would have touched down around 5:50pm, just before last light... cutting it very fine, but still before last light ( Official Sunset at Leigh Creek is 17:28, Last Light 17:55 ). The apparent extra 1/2 hour of flight time needs to be factored into working out the possible chain of events leading to such a tragic outcome.

Looking at the photogragh, they did well to crawl out... not a lot of room between the canopy and the fuse.

I stand corrected.. you are right. Thanks.

Greetings All, My thoughts re the RAAus BAK exam... Just did the exam last week, and while I found most of the questions fairly straightforward, there were a few curly ones... or maybe my memory is not as good as it used to be! I passed with a reasonable result, but what this fundamentally tells me is that I have the minimum knowledge deemed sufficient at this stage to safely continue my flying training. If I had failed miserably, this would mean there were serious gaps in my knowledge, and it would be in my best interest to put in whatever time and effort was required to get 'up to speed'. The aim, surely, is to have a sound understanding of BAK, presumably because it might come in handy one day :thumb_up:. Passing the exam is secondary, and as someone said earlier in the thread, the primary aim should be to be knowledgeable enough to 'fly' through the test. In spite of the temptation :devil:, if someone were to offer to show you the Q & A, don't be tempted! If you pass by less-than-straight-up-and-down means, you really are only selling yourself short, and may be missing a vital opportunity to know what you don't know, while there is still time to learn safely on the ground! Cheers, Harro

And just to add support for Drifter's outlook ... We used to be taught that theoretically, a bumble bee can not fly! Lucky they don't know how to read the theory books then, eh! ;) For those (like me) that like/need to understand the workings of a duck's rectum, the information is out there... but can be a bit of a liability sometimes. Horses for courses. I would always like to think the designers of all our aircraft were well versed in both the theory and the practical. In my 'previous life' (decades ago), I've seen designs that frightened the socks off me. And yes, people died as a result. Now I am happy to participate on the piloting side of things, so as long as the duck's healthy... Bee safe!!! :thumb_up: Harro

On Mr. Bernoulli...aerodynamics 101 G'day all, Time to weigh in on this, with a slightly theoretical bias, so for what it's worth... Bernoulli's theorem is not really that difficult a concept to grasp. Bernoulli found that the 'total pressure' in an incompressible flow along a given streamline is constant! There, that wasn't so hard! But what does it mean? In technical terms: for a given 'streamline', 'static pressure' + 'dynamic pressure' + a gravitational potential term = 'total pressure', which is a constant. As applied to the 'low speed' aerodynamics of an aircraft (less than 1/2 the speed of sound), compressibility effects of air can be ignored, as can the gravitational term. This simplifies then to: static pressure + dynamic pressure = constant. Knowing this means that we can calculate, for instance, IAS from a pitot static system, which is fortunate. But can we use Bernoulli's theorem to calculate the lift (pressure distribution) on a wing? Short answer, no. However, to say that Bernoulli's theorem doesn't apply to the lift generated on an aerofoil is, imho, a non-sense. It certainly gives us some insight as to why the pressure varies accross an aerofoil. Where the velocity of the airstream changes, then the 'total pressure tango' between dynamic pressure and static pressure occurs, hence the possibility to produce a net lifting force if we are clever enough. Remember, the only force transmitted to the wing from the airflow is by means of 'pressure' acting on an 'area' of that wing. Force = pressure x area, so if we sum up all the respective regions of 'pressure x area', we end up with a resultant force, which in aviation we arbitrarily express as 'lift' (perpendicular to the 'freestream' airflow), and 'drag' (parallel to the 'freestream' airflow). What we need is to be able to calculate these lift and drag forces. The whole concept of engineering is about producing 'models' to enable us to make a reasonable prediction of cause and effect. Bernoulli's theorem is just one such model, within its limitations. Mr. Newton's laws represent another handy and reasonably reliable model, within their limitations. One way to calculate the lift and drag forces would be to map the pressure distribution around the aerofoil, and sum up the component forces to find the resultant. Unfortunately, Bernoulli's equation can't do that for us. Bernoulli's theorem only applies to streamlines absent significant 'viscous effects'. This 'inviscid flow' assumption breaks down in the boundary layer, and in the wake. To get around this, we measure the lift and drag resultants (and pitching moment)directly in a wind tunnel, and establish 'coefficients' (CL, CD and Cm) to be used in calculations. This model works reasonably well because it bypasses the need to understand exactly what is happening in the boundary layer, and models only the measured outputs based on the measured inputs. Another method might be to estimate the change in momentum in the wake (Newton's laws). This will tell us the 'reaction' necessary in the wing to produce the change in momentum of the airflow, but the reaction force on the wing is still the sum of varying pressures (Bernoulli again) acting on their respective areas. The change in momentum is an inescapable consequence of lift production... think of a propellor, or a helicopter rotor downdraft. The momentum method tells us only the total reaction, and nothing about the nitty gritty e.g. centre of pressure. As stated earlier in this thread, lift can be estimated by either model, with the results in close agreement. The models don't change what actually happens, but are just our attempt to get a handle on it, so that we can design aircraft that fly! Also... There has been some discussion about the 'fidelity' of adjacent air molecules i.e. do they meet up again at the trailing edge, or have a fling? I've never liked the 'longer path' explanation for increased velocity, and hence reduced pressure, because it presumes 'fidelity' (to carry on the analogy). Without doubt, in a three dimensional airflow around an aerofoil producing lift, the molecules do not meet up. The opposing spanwise flows on the upper and lower surfaces of the wing act to keep the previously chummy molecules apart. As far as I know, aerodynamic theory does not require such a condition that the same molecules meet up at the trailing edge either. A gentleman named Mr. Cutta established a theory (model) known as the 'Cutta condition', which represents the only possible steady state solution for an airflow around an aerofoil. This has to do with the theoretical concept of 'circulation' superimposed into the airflow to account for the observed facts. Initially the rear stagnation point in an aerofoil (set to produce lift in the normal, upright sense) is forward of the trailing edge, on the upper surface. This creates what is called a 'starting vortex' at the trailing edge, forcing a unique 'circulation' value into the airflow around the aerofoil just sufficient to move the stagnation point to the trailing edge i.e. the upper and lower surface streamlines meet happily at the trailing edge. At this point, the transient starting vortex is cast off into the wake never to be seen again, and circulation is maintained resulting in a stable airflow. While there are numerous other constraints, there is no intrinsic requirement for the previously adjacent air molecules to meet up again at the trailing edge. Any questions??? Regards, Harro

Re SkyFox manual... Hi Rodger, I am learning to fly the SkyFox, so I would certainly like to get a copy of that as a reference. That's a fairly big file to email. How do you suggest is the best way to send 26Mb over the airwaves? Cheers, Ian H

G'day all, Well, finally making my first post :thumb_up:... been lurking for a while. I started my flying training a couple of months ago... in the SkyFox at Caloundra. So far, I am enjoying it immensely... (even the HF exam!;)). I have been meaning to take up flying for too many years, and finally figured it was about time to just do it. Best decision I ever made. Anyway, more from me in due course. Cheers, Ian H