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He stepped on the Rudder and redefined Va

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He stepped on the Rudder and redefined Va

Old 7th Oct 2013, 16:31
  #301 (permalink)  
 
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Originally Posted by AirRabbit View Post
And it’s nice to know that other members of that particular union participate in this forum! Welcome aboard!
Thanks Rabbit, but to be clear, I'm not a gas-passer, not even AF (although I do fly a Herc) I just came across the document while reading the AA587 Report, and posted it because it pretty neatly dismisses the 2 of the fallacies being repeated here. To wit:

That before AA587, nobody imagined you could tear a fin off with rudder reversals.

and

Airbuses are the only planes which are susceptible to this.
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Old 7th Oct 2013, 17:00
  #302 (permalink)  

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This has happend before.



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Old 7th Oct 2013, 17:03
  #303 (permalink)  
 
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I am impressed by so many skills and knowledge together !
Thank you to Machinbird, Owain Glyndwr, Chris Scott, Brian Abraham, Hobo, PJ2, misd-agin, and others. I apologize as I need a littler more time to answer...

It seems that Harper-Cooper scale is generalized with US aircrafts, but nothing else with Airbus unless due certification is done in USA - and it seems it has not been the case with the A300-600R modifications, according to the APA document. A european manufactor test pilot is not independant to rate their own aircrafts' qualities.

A question about Harper-Cooper rating : is it done with and without Yaw Damper on ?
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Old 7th Oct 2013, 17:18
  #304 (permalink)  
 
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roulis

A european manufactor test pilot is not independant to rate their own aircrafts' qualities.
But they routinely do so in the flight test development programmes to ensure that there are no problems and to sort them out if necessary. Before any aircraft gets certification its handling qualities are checked again independently by one or more of the airworthiness authorities' test pilots. Whether or not they use the Cooper scale is a matter of choice for them really - you don't have to give an aircraft a numerical rating to say whether it is pleasant and safe to fly - subjective judgements are just as valid and in practice a Cooper rating is nothing but a numerical statement of a subjective judgement. APA were just making waves.....

A question about Harper-Cooper rating : is it done with and without Yaw Damper on ?
Whatever the test pilot is trying to assess. The Cooper scale is just a numerical scale which can conveniently be used to methodically categorise the relative acceptability of various configurations.

Last edited by Owain Glyndwr; 7th Oct 2013 at 17:35.
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Old 7th Oct 2013, 17:34
  #305 (permalink)  
 
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A Squared – hey, a Herc pilot is close enough in my book. I will say that I, too, was surprised at the apparent lack of knowledge evident in the airline industry about the vulnerabilities of airplanes should there ever be an over application of flight controls – particularly control reversals – and most particularly reversals to the stops.

I think that many instructors (usually they were the “older” heads at most airlines) who advocated the use of rudder (like those training at AA for their AAMT -?- training course) were perfectly correct that it was permissible to use rudder in the manner they described – which was not “if you use it, use ALL of it” … but rather, “use it for what it can do,” … and I believe they either didn’t have the time (in a typically limited airline training environment) or they were under the impression that those in their class had a similar background to their own, where it was drummed into your head to “remember where you are and what you are doing – and specifically that cowboys are on horseback, not at 30,000 feet and at 75% the speed of sound.” The portions of the AA course with which I was somewhat familiar, advocated the judicious use of rudder – and use of full rudder WAS acceptable, if it was necessary – but those cases were acknowledged to be few and far between. In fact, the times where rudder use was deemed acceptable in that portion of the course I saw (flew), was when the nose was unacceptably high and the crew could not get it down. The procedure was to roll the airplane and (the word used was “pressure”) then “pressure” the down side rudder to bring the nose back to the horizon.

In fact, my recognizing the fact that knowledge of control applications in transport category airplanes was particularly sparse in the airline community is what put me on a “bent” to increase the requirements for training. I’m not describing merely an increase in the time spent in training, but to train on what is needed to be known and to train to a competent level of performance. I know that many do not like the idea of additional requirements – particularly if they come from a regulatory agency – but, honestly, I don’t know of another way to get where we need to be. That also put me into a frame of mind that says we all should not just take what we are given from “the man,” but that all of us have a right to expect (in fact demand) that the regulators demand every bit the same level of competence in their employees at their jobs as they expect from the industry. There are a few individual regulators I know who feel the same way – and we should be including them in our discussions on the kinds of things this industry needs. And, I may be overly simplistic, but I don’t think the industry can get there without the regulators being involved up to their necks.

Oops – sorry – as you can see, I can get on my soap box pretty easily … I’ll step down now and go about my business. Anyway – thanks for your participation – and your professionalism.
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Old 7th Oct 2013, 18:41
  #306 (permalink)  
 
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For the benefit of those who don't frequent the Bizjet Forum: The OP appears to be some kind of troll (no surprise, I had that suspicion after his first post on this thread)
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Old 7th Oct 2013, 20:31
  #307 (permalink)  
 
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Teldorserious,

In case I'm not on your "ignore" list, you may be surprised to see that you're not on mine - yet.

But by including that story from soon after the AF447 acccident you have betrayed your primary motive for starting this thread: as a vehicle for yet another anti-Airbus rant from the west side of the pond.

It seems there is a noisey minority of poorly-informed, pro-Boeing bigots which cannot accept the fact that the Europeans have finally produced a range of airliners that - backed by a first-class marketing organisation - is matching the sales success of America's finest; instead of merely being technically superior, as so often in the past.

Get over it?
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Old 8th Oct 2013, 01:44
  #308 (permalink)  
 
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A recent thread said the B787 is designed to be able to be flown by equally incompetent Airbus pilots because of it's automation. You don't have to really know how to fly any more, just program the automation. Why even have pilots if they don't have to know how to fly. Make them all automatic with no pilots. Problem solved.
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Old 8th Oct 2013, 03:13
  #309 (permalink)  
 
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Bubbers, to a certain extent the FAA is forcing us to do that. We've basically being told we have to design for the 3 sigma 'bad' pilot - to take credit for what 99% of pilots would do is considered depending on "usual pilot skill"

The rational is that "inappropriate crew action" in response to something else going wrong is a leading cause of crashes. Therefore we need to design to prevent "inappropriate crew action", which sounds reasonable on the surface. But the way it's been implemented, if any dumbass pilot has ever made a mistake, we need to assume that every pilot is a dumbass and will make the same mistake I'm willing to bet significant money that the Asiana 777 crash at SFO will drive new regulations (or a 'reinterpretation' of an existing regulation) to require automatic protection of airspeed during critical flight phases (never mind that autothrottle/autothrust already do that if the dumbass bothers to turn it on).

Get used to it, it's not going to get any better . It's also why I think the pilotless (passenger carrying) airplane will eventually happen. When the primary purpose of the airplane avionics becomes preventing the pilot from doing something stupid, it's really not that big of leap to take the pilot out of the equation entirely
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Old 8th Oct 2013, 04:42
  #310 (permalink)  
 
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tdracer, thanks, even if it is bad news. Keep building those Boeings, I love them, but never thought Boeing would join the AB philosophy of making their product idiot proof.
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Old 8th Oct 2013, 05:57
  #311 (permalink)  
 
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Chris Scott, don't take any notice whatsoever of Teldorserious. He has a habit of involving himself in things of which he has completely no knowledge. The sciolist note on the bottom of the page was partly in response to his continual wet dreams. He has no aviation background, and has no interest in learning, beyond his own preduces.
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Old 8th Oct 2013, 06:42
  #312 (permalink)  
 
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Chris,

If you are still wondering about ignore lists you might like to consider extracts from a couple of posts:

Teldorserious 24th Sept Bizjet forum Piaggio Avanti thread post #32


Can't remember the last time I stood on a rudder in a jet,
Teldorserious 29th Sept Tech Log He stepped on the rudder etc thread post # 92


You can believe that all planes are like this, completely nullifying what us pilots do every day in training, in x winds, in single engine ops, or day to day flying, stepping on the rudders all day long, back and forth, at all sorts of speeds.
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Old 8th Oct 2013, 06:56
  #313 (permalink)  
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Owain, the advice is certainly well-founded - one can very quickly sense someone who's playing with people and into the ignore-list they go! There's too much good stuff to be trifling or fixing those who offer up nonsense.

Brian, Chris;

The B-over-A prejudice most certainly exists. Seen it, heard it, then as now. It's not going to go away because, normal personal preferences aside, it is based upon politics and emotion and not on technical or design fact.

I've flown both A & B manufacturers, plus old Douglas and newer Lockheed products. They all do the job very nicely. Of course, stats-and-facts are anathema and an inconvenience to those who harbour personal attitudes towards one airplane or another. But the Boeing Statistical Summary of Commercial Jet Airplane Accidents (1959 - 2012) speaks for itself because the numbers are available to anyone.

The key, as we who actually do (or did, ) this work know so well, is in deeply knowing one's airplane, not letting up the studying where one's employer leaves you at the end of your training, not believing one is smarter than the design engineers and test pilots when it comes to operations near, at and outside the envelope, and most important, suspending one's shiny ego in favour of curiosity and life-long learning, which means quiet confidence in one's ability combined with humility - rare these days of adherence to empty personal "branding" habits.

In this profession these are the behaviours that keep one alive in an airplane and out of the office and/or the newspapers. Without animosity, folks like the OP of this fine thread come and go - seen them dozens of times and they're all the same. They eventually fade, tiring of the game, while those who know their stuff carry on in spite of interlopers, to share their valuable knowledge and observations.

Most of the time for the better, one takes the catalyst for discussion where one finds it and what a discussion it remains!, despite our OP's and a couple of others' efforts to take the discussion away from those who have made the thread with their unique contributions while those who for whatever reason(s) pretend to know move on to whatever they're better at. It's the nice thing about "the free marketplace of ideas" and the facts of flight as we know them.

Last edited by PJ2; 8th Oct 2013 at 07:56.
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Old 8th Oct 2013, 15:02
  #314 (permalink)  
 
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Thanks Brian, Owain and PJ2 (aviator-philosopher!).

Overall, the illuminating side of this discussion has been well worth the comparitively minor hassle of Dozy's "faint, buzzing noise, like an angry wasp banging against a window."

There are many fine contributions here, but one must particularly admire Owain's and AirRabbit's insights into design and certification, and it's good to see Machinbird back. Where are all the other usual suspects?
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Old 8th Oct 2013, 15:11
  #315 (permalink)  
 
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Originally Posted by PJ2 View Post
...is in deeply knowing one's airplane
Presumably not in the Biblical sense though - that would just be wrong!

Otherwise I totally agree - and I'm impressed at the knowledge and patience shown in this thread. The one thing that still saddens me is when the old canard about the FBW Airbii (which wasn't even the subject of the thread) being designed for "incompetent pilots" arises, when nothing could be further from the truth. For one because a pilot does not have to be incompetent to make the occasional mistake, and also because that's just a single facet of the envelope protection philosophy, and arguably not even the most prominent one at that!

Last edited by DozyWannabe; 8th Oct 2013 at 15:11.
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Old 8th Oct 2013, 15:51
  #316 (permalink)  
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Dozy, "Presumably not in the Biblical sense though -" LOL.

I've noticed over the years that there are very few pilots who have flown and know the airplane (in the non-Biblical sense), and make statements like, ". . . designed for incompetent pilots".

At the same time, I see that, contrary to what is known thus far by the NTSB, the B777 autothrust system is being blamed by a certain group for the SFO accident.

Chris Scott, I agree in re OG's and Air Rabbit's contributions - particularly helpful on the AF447 threads. Most pilots won't have "Davies" and so sources of fundamental aeronautical knowledge which is rarely if ever taught at the major carriers, are themselves, rare and I think discussions like this on a Tech forum are well worth the effort. One cannot know where this kind of technical discusson will go with new crops of "computer - generation" pilots who, if it is to be more automation as a result of unsubstantiated comments like, 'the throttles didn't work', soon may not know the pleasures of manual flight.
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Old 8th Oct 2013, 16:36
  #317 (permalink)  
 
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@flyboyike - I'd be out on my ear if there was a screening process! What the forum does provide is a unique and brilliant window into aviation for those who are interested in learning, and unfortunately what comes with that is a degree of baiting from those who aren't interested in learning.

And PJ2 - I'm of the computer generation, not even a pilot, and I own a well-thumbed copy of HTBJ.

Last edited by DozyWannabe; 8th Oct 2013 at 16:41.
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Old 8th Oct 2013, 17:10
  #318 (permalink)  
 
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@ Machinbird, Owain Glyndwr,

With your's teacher definition of dutch roll, Owain Glyndwr, the pilot does never need to do something to stop it. The yaw damper or the raw stability of the frame does the work. Once more "do nothing"...

With my teacher's definition of dutch roll (which has been more a flag in my brain than a complete definition -I told the context to emphasize that fact) , it works only if there is a dutch roll problem, not only a dutch roll...

1 vs 1.

The first order - surely more complex for the total plane- has already an oscillating output after an oscillating input - turbulence, yawcdamper failure, etc. -, and the pilot gives a second oscillation to try to stop the dutch roll "problem", starting resonance.

Semantics? Agreed.

Now we all know that after the AA587 we do not need to redefine Va. We need Va for what it isx not more, not less.

What we need is a new point of view that does not exist in our regulations of certification concerning RESONANCE. It could be builded on Machinbird's post and enhanced from his first text and his experience of PIO and high level flight experience. His post with Bode figure with numbers is a good beginning of what we have to think about the dynamic system.

In any case what is missing in our certification and knowledge is a quantified reference to dynamics of the transient parts of the plane's oscillation, Pio and other APC.

Resolving easy differential equations when flying (as I did) or reckoning dutch roll characteristics before computers (as you did 50 years ago) needs notthing more that what Richard Feynmann taughted to all his student : have no hesitation on basics calculations, integrals, aso.

Last edited by Jetdriver; 9th Oct 2013 at 00:53.
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Old 8th Oct 2013, 22:15
  #319 (permalink)  
 
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It's not like Teldoserious is unique in that regard. In fact, I'm surprised that the alleged PROFESSIONAL Pilots Rumor Network has no screening process outside of individual airline private sections. The result is posers galore.
So-called “posers” are one thing, but I have no problem with those with legitimate ignorance who are seeking knowledge. In truth, sometimes, a different perspective breaks down a lot of barriers.

Those who have been here for longer than just a while probably know that I have a well-deserved reputation for posting L-O-N-G posts. I believe the reason is that in one aspect of a former life I used to teach “communications” – and one of the quotes I used often was “The most often committed error in the art of communications is the mistaken belief that it has taken place.” This gives rise to the 3-aspects of communications: 1) what I say; 2) what you hear; and 3) what I intended to say. As a result, I often find myself using a lot of words – explaining the same thing somewhat differently, in an attempt to reduce the potential of errors by me in speaking, and the potential of errors in hearing by those who are listening. If there are some here who are attempting to learn something from the knowledgeable contributors who participate, but to those contributors these "knowledge-seekers" sound like “posers” in that attempt, I would say “back up and play it straight.” There are some here, who admit they are not aviators, but still are intrigued by some aspect or another of this job function – be it life style, fears, triumphs, or whatever else may be interesting to those on the other side of the glass. It’s been my experience, that if I wanted to know something about a particular job function or profession – about which I know little – trying to sound like an “insider” will, either earlier or later, fall on its face. So in the interest of time, I usually just blurt out what I’m after and why I’m asking. Usually, I get more information than I can process – and in the interim of wading through all the jargon and lexicon to get to a place I can understand, I’ve often generated some very good friendships.

When I’ve had an interested student ask the kinds of questions that students ask (either academically or aerodynamically) – through my attempt to provide that student something that can be usefully understood, I usually find myself trying to explain the same thing differently, most often using different words each time (which is what generates my reputation for using a lot of words) – and sometimes doing that, I am able to see the issue from such a different perspective, revealing a lot more of the subject, and providing me a better understanding of the situation, which, in turn, does 2 things: first – I learn more about the specific subject for my own use; and 2) I find a better way of expressing what it is the questioner really wants to know.

It may be true that I will fail to break through to any who may be lurking behind some false façade of “aviator.” However, maybe, just maybe, instead of trying to finesse a conversation with someone the questioner believes would not respond unless it were to a perceived equal, that questioner may feel somewhat more encouraged to simply and openly ask the question. I think those questioners would be quite pleasantly surprised.

One other thing – I’ve also found that sometimes the questioner is a closet-wannabe. There should be no guilt in being a “fan” of other persons or of interesting professions – and more often than not, the open fan is often accepted as at least a guest, if not a distant relative, at the “family” dinner table. One can simply NOT have too many friends – regardless of their background.
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Old 8th Oct 2013, 22:52
  #320 (permalink)  
 
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Do you keep that correspondence with your "Certificate of Awesome" signed by Neil Armstrong and Chuck Yeager?
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