He stepped on the Rudder and redefined Va [Archive] - Page 2

BARKINGMAD

5th Oct 2013, 15:10

Have I missed something during the long transition from mil to civil aviation?

Or possibly neurons dissolved by too much sleeping lotion has erased the memory?

As far back as I can recall, rudder use in swept-wing aircraft was a delicate subject, as was the teaching of its use on the same 'frames.

On the Gnat Advanced training course in the RAF, we were given ONE demo of its use and effects at high altitude (to allow for the subsequent recovery if needed!) and that was it. Yes, squeeze it to remove drift before X-wind touchdown, but no more. The skin of the fin was cutaway on those 'frames with cracks in the attachment brackets, so we could compare them during walkaround, having "memorised" the crack shape and extent as we signed out the tech log in the line hut. Any noticeable discrepancy and it was back to the hut for another, please?!

This was as a result of fatalities due to fin separation in previous accidents as the phenominal rate of roll of that aircraft was the perceived cause of the early fatigueing.

Now it appears from the A300 accident that coarse and assertive rudder use was at one time being trained as an upset recovery technique. Where did the disconnect intrude into the mind of those who thought this was an acceptable and beneficial method of regaining control of a swept-wing public transport medium to heavy aircraft?

Forward the tape to the 90s and the recommendation from Mr Boeing that the full&free rudder check on the 747 should take 2 seconds from neutral to full deflection, both ways, and avoid crashing the rudders against the stops with coarse inputs.

This was apparently introduced as the routine inspections luckily discovered the PFCU attachment brackets were cracking as the barn doors on the 747 VS assembly were being crashed from side to side against the stops by the inadequately trained gorillas then operating them.

Fast forward the tape (yes I know, VHS-speak!) to today, and observe the massive rudder on the 73NG being slammed against the stops by the current crop of Captains, and if you don't see it from outside, then try sitting in the seats in the aft row and FEEL and HEAR the clunk as they hit the stops.

It gives me the chills when I feel it, and I am forced to ask what are the type-rating trainers and the line trainers up to by allowing this crass, clumsy and careless handling?

It all goes to show that there are some lessons in this game which we have forgotten, at our peril, when it comes to having respect for the flying controls and their effectiveness.

Are there any NG engineers out there who can reassure me the NG rudder assembly is NOT suffering from this abuse so that I'll sleep easier?

roulishollandais

5th Oct 2013, 18:17

[...] certification “loophole” [...]

That "certification is "Europe" certification ! Terrifying !
Thank you misd-agin

Did the other aeronautical agencies try to copy ?

Fast forward the tape (yes I know, VHS-speak!) to today, and observe the massive rudder on the 73NG being slammed against the stops by the current crop of Captains, and if you don't see it from outside, then try sitting in the seats in the aft row and FEEL and HEAR the clunk as they hit the stops.

It gives me the chills when I feel it, and I am forced to ask what are the type-rating trainers and the line trainers up to by allowing this crass, clumsy and careless handling?

It all goes to show that there are some lessons in this game which we have forgotten, at our peril, when it comes to having respect for the flying controls and their effectiveness.

Are there any NG engineers out there who can reassure me the NG rudder assembly is NOT suffering from this abuse so that I'll sleep easier? Have nice dreams BM !

VinRouge

5th Oct 2013, 18:53

there were a number of issues with this accident.

design. The -600 had different aileron control sensitivity to that of previous models. in turn, this led to the engineers tweaking the control loading required for max deflection, making the rudder more sensitive. this meant pio in yaw was increasingly likely.

this was a minor point; the big one was the negative training recieved in the simulator, in particular, the use of rudder to control roll during an upset. i believe, but am not certain, that the sim profile actually had the instructor turn down the control authority of aileron in the sim, and thus reinforcing the inappropriate use of rudder to control yaw.

a few on here need to do a bit of research. go off and read up on dynamic vs static loading requirements, then have a look at part 25 design requirements. understand the effects of moment of inertia, angular acceleration and aerodynamic damping and you will realise that no re-definition of Va has occurred.

do multiple, max amplitude in phase doublets on the rudder on any aircraft enough and you will snap the fin off.

Teldorserious

5th Oct 2013, 20:24

Una Due Tfc

5th Oct 2013, 20:36

Sorry to intrude lads, but back when this happened I was training in an MRO and our instructors ran the (approximate) maths to show the loading this fin was under. They came to the conclusion that any large jet transport aicraft would have lost the fin under that loading, composite or aluminium. The increase in load with each reversal was enormous. The fin on that A306 actually failed far above it's max load certification, our engineers were impressed at how long it held on for.

If you recreated the circumstances on a Boeing, Embraer or any medium or heavier aircraft, that many reversals at that speed that low will rip your tail off was their conclusion

Teldorserious

5th Oct 2013, 21:53

UNA - There is no way your instructors were aeronautical engineers with the Airbus structural data, then punch in an accurate description of the wake turbulance event, then assuming they actually had the actual correct FDR inputs instead of some 'gamed' numbers, then of course found the only Arnold Swarzeneger pilot in the fleet that could bang 140 lb inputs back and forth in the sim to come up with 'sideloads' that imposed 'vertical loads' to take the tail off.

I mean I have been in the sim where I asked them to do a dual bucket deployment. ha. Trust me, these guys can't simulate the tail coming off. At best they can sit around a table with the numbers Airbus gave them, trying to convince the FAA that some perfect storm of rudder input and wake turbulance, conbined with a super special snowflake sensitive rudder system, that some how got through flight test cerfication, but you know, now needs to be recertified, because, you know..NOW they know it's quirky.

Come on.

AirRabbit

6th Oct 2013, 01:56

I know that no one has asked, but … after reading the recent posts and looking again at the NTSB animation, I’d like to offer my thoughts … but before I do there are 2 things I need to explain:

1. Proprioception is awareness of the position of one’s body in time and a defined space; and the proprioceptors are located in subcutaneous tissues of muscles, tendons, joints that respond to stimuli applied to the body. There is conscious and subconscious proprioception – in a simplified description, one is recognized, processed by the brain, and recognizes a solution or response … and the other is not processed by the brain, the body simply responds … much like quickly jerking your hand away from a hot stove, or blinking your eye if it is threatened.
2. Anyone who flew the B727 very likely received a substantial amount of training on how to recover from a “dutch-roll.” And you probably recall that the primary control response was the aileron (control wheel) and the process was to recognize the direction of bank and apply a large amount of aileron opposite the roll, and immediately return the control to the neutral position. When the airplane began to roll in direction of your last aileron correction, and as soon as the airplane passed wings-level, again apply a large amount of aileron (control wheel) against the rising wing – or opposite the roll – and immediately return the controls to neutral. It’s the “return to neutral” part that is every bit as important as the control insertion to stop the “dutch-roll.” This is what all maximum control applications during certification require … return the control to the neutral position.

OK – now for my thoughts on the AA587 circumstance.

We know about the rudder sensitivity (if we call it that – but even then, the rudder shouldn’t have been all that much of an “unknown” to someone who’s flown the airplane as long as this crew had flown it) and we know that the F/O had quite successfully transitioned the first wingtip vortex (in fact, looking at the animation again – one could call it quite professionally – in that he allowed the inherent stability of the airplane to do it’s “thing”), but I think that encounter really heightened that F/O’s “fear factor” to the point that he was operating on “the panic bubble” – where he was not yet quite panicked, but he was right at the edge. Remember the F/O questioning the Captain about the ATC clearance, asking if the Captain was “comfortable” with the takeoff following distance? I believe the F/O was showing preliminary signs of nervousness, even before they pushed the throttles forward for takeoff. And I don’t think he had rid himself of that nervousness – I think it was peppering the back of his mind throughout the climb-out.

Pilots typically set up a mental regimen by which they fly (which might be described as …“scan – mentally process – feel – mentally process – scan – mentally choose a response – physically respond – scan – mentally process – feel the motion – visually confirm the motion cue – mentally process – etc.”). I think the F/O was riveted on flying the departure and controlling the airplane – and doing so more intently than he normally would. I think he was spending a lot of subconscious effort being concerned about where the JAL747 was ahead of them WHILE concentrating on his departure – still nervous but still performing. Then – bang, they encountered the 1st vortex. It jostled the airplane a bit – and I think the F/O did just what he was trained to do – keep the controls essentially neutral – correcting minor deviations as necessary – most notably, applying a very minor roll correction. And the vortex was successfully transitioned … but … and here’s the real BUT… I think that first event escalated the fear the F/O had been forcing down and brought it right up to scream in his face! I call it “the panic bubble.” He wasn’t panicked – yet. But he was nowhere near the calm F/O that questioned the Captain before the takeoff roll.

Had they not encountered that 2nd vortex, the F/O very likely would have taken a couple of deep breaths and, within the following 5 to 10 minutes, calmed down to the point that everything would have seemed to have been, and likely would have been, “back to normal.” I think he was beginning to mentally process what had just happened (what he saw, felt, heard … what controls he used, how much input, held for how long, any repetition required, etc.) as he began a turn to stay on the departure course … and he knew he had to continue the departure. I think the Captain noticed a change in his F/O – probably not overt … but a change nonetheless – and I think that was the reason he attempted to calm the F/O, and probably himself, by nonchalantly asking “a little turbulence there, eh?” just after the encounter subsided. But I believe that attempt at “down playing” what had just happened didn’t penetrate the F/O’s “panic bubble.”

He knew he had to maintain pitch, bank, heading, altitude, climb rate, airspeed, etc., follow the published departure AND follow ATC instructions – but I think he was more concerned about the JAL747 that he was following. I think those things grew and grew in significance and the panic bubble was growing, not reducing. Now he was trying to recall just how bad that turbulence had been and how bad it could have been. How close was that other airplane? In short, he was mentally pushed to the limits – but he was still trying to perform his duties of flying the airplane. However, before he could get things back into the regular process with which he was familiar … yep … BANG … 2nd vortex encounter. But here, the F/O was spooled up – quite a bit – and now, the panic bubble burst, and his response was one of panic – his proprioception receptors (recognition not requiring processing by the brain) fired, and knowing his airplane was being forced into more of a left bank – and having already established a 23° left bank – just like snapping your hand away from a hot stove, this F/O slammed a right control wheel and a corresponding right rudder control input – almost to the stops. Whether the following and all subsequent control applications (both wheel and rudder) were a result of his proprioception or his realization that what he just did was likely too much – I can’t say … but when you’re responding out of panic, there isn’t much room for recognizing magnitude and incorporating finesse.

bubbers44

6th Oct 2013, 02:17

tdracer

6th Oct 2013, 04:11

UNA - There is no way your instructors were aeronautical engineers with the Airbus structural data, then punch in an accurate description of the wake turbulance event, then assuming they actually had the actual correct FDR inputs instead of some 'gamed' numbers, then of course found the only Arnold Swarzeneger pilot in the fleet that could bang 140 lb inputs back and forth in the sim to come up with 'sideloads' that imposed 'vertical loads' to take the tail off.

So, Teldorserious, how do you explain that in the aftermath of the crash, Boeing structural engineers did the same analysis and came up with the same answer - that the same rudder inputs would have failed the tail on a Boeing aircraft?

You never directly answered my earlier question - do you honestly believe the NTSB is corrupt and falsified the data?

And if you're willing to answer yes to that, I have another question: Why would they do that? Why would a US Government Agency falsify data to protect a foreign company - a company that competes directly with one of the USA's largest companies? And why would Boeing go along with it?

Oh, and while you're at it, why would American Airlines go along with it - exposing themselves to untold millions in lawsuits - when they could have piled all the blame on Airbus for a defective aircraft?

A Squared

6th Oct 2013, 04:26

So, Teldorserious, how do you explain that in the aftermath of the crash, Boeing structural engineers did the same analysis and came up with the same answer - that the same rudder inputs would have failed the tail on a Boeing aircraft?

Or along the same lines, how do you explain that even before the AA crash, Boein issued an amendment to the Operating Manual of the KC-135 stating that reversals of rudder application can cause the vertical stabilizer to fail. (previously posted in this thread)

Interesting, isn't it, how Teldorserious just seems to ignore these things that don't fit her fantasy.

Brian Abraham

6th Oct 2013, 06:14

God, I hate having to repeat myself, but Teldorserious ain't an aviator in any form or fashion, so I fail to understand why any take his posts with any measure of credibility, or even engage him in conversation.

PJ2

6th Oct 2013, 07:10

Brian;

It's interesting. Teldorserious started the thread and frankly, I like where the thread itself has gone; I have learned a great deal from others and am putting some of it to use in my flight data work.

But each poster sooner or later proves his or her capabilities as well as his or her disposition towards civility-above-all-else-including-ego, and serious discussion when engaging other like-minded serious professionals, many of whom come here for the joy at the level of such discussion as well as great information.

It's ironic that after beginning, his subsequent posts are puzzling, but there it is, not the first, nor the last occasion we'll see. He's been on my ignore list for some time.

roulishollandais

6th Oct 2013, 10:22

1. Proprioception is awareness of the position of one’s body in time and a defined space; and the proprioceptors are located in subcutaneous tissues of muscles, tendons, joints that respond to stimuli applied to the body. There is conscious and subconscious proprioception – in a simplified description,oneisrecognized, processed by the brain, and recognizes a solution or response … and the other is not processed by the brain, the body simply responds … much likequicklyjerking your hand away from a hot stove, or blinking your eye if it is threatened . I think we have all had vertigo. Training lets us overcome it. It saved my butt once.
As a freefaller we used unconscious proprioception and developed subcutaneous muscles and sensors like the dancers but we use too sight and other senses to control body attitude ref horizon or to join relative freefallers . During the freefall each time we leave the aircraft we fall first in low gravity and have to find the good dynamic balance with very little movements. As pilot, and specialy IFR pilot we do not trust proprioception. Itwould be a dangerous fault denying IFR flight possibility, but ONLY instrument informations -exception is position of the body in the armchair, neck position, and control of fingers, legs and fixing the inside of the body. As Bubbers44 says training overcomes vertigo created by contradictory proprioceptions. Performance in spinning armchair with blinded eyes used for astronauts training shows that difference : freefallers are much better than fighter pilots. Pilots trust instruments not body feelings.

Brian Abraham

6th Oct 2013, 13:24

Totally agree with the thrust of your post PJ2, only some have not learnt to ignore his exceedingly strange and ignorant posts. Renewing his instructors rating, give me a break.

SMOC

6th Oct 2013, 14:25

I am going to have to get into an Airbus sim...

Slow flight, departure stalls, stall spin recoveries, wake turbulance, microbursts...

Teldo... this comes to mind! :}

http://virtualmystic.files.wordpress.com/2008/06/simcrash.jpg

Brian Abraham

6th Oct 2013, 15:27

SMOC, The statement "Personally, I would'nt let Buba pull my kids wagon" certainly applies to our friend.

misd-agin

6th Oct 2013, 15:27

OK465 - thanks for the correction/clarification.

I've seen a chart listing breakout forces, force needed for full travel, pedal travel, etc. I thought it was in the submission but apparently it isn't.

Teldorserious

6th Oct 2013, 18:02

Brain are you still mad that I outted you as a fraud? Why the mods put up with your incessant trolling is beyond me. Maybe they don't care?

AirRabbit

6th Oct 2013, 19:13

Any pilot that takes 5 to 10 minutes to regain compsure isn't a safe pilot. By then it is all over. Maybe 5 seconds if he is slow. One second if he is normal. We don't have the luxury of time in the cockpit. Some things require immediate reflex actions, some don't.

Deciding to divert to an alternate, take your time. Wake turbulence or windshear a second is too long.

I’m not describing the necessity to compose one’s self … I’m describing the ability to not react out of panic, but rather function as you have been trained, choosing what your reaction will be – and I’ve described this in pilots as being somethink like …“scan – mentally process – feel – mentally process – scan – mentally choose a response – physically respond – scan – mentally process – feel the motion – visually confirm the motion cue – mentally process – etc.” this pilot was doing that up until the 2nd vortex … but I think he was on the verge of panic, keeping it under control, and likely, working his way out of it. Unfortunately, the 2nd vortex hit and burst that panic bubble – and from there everything he did (in my opinion) was the execution of what he knew but motivated out of panic. As I also said previously, most people think they know how to recognize someone who has panicked … perhaps some may … but I do know that when you’ve seen someone really panic, it’s something you won’t easily forget. And unless you know the person, or are really familiar with the circumstances, you might not recognize that the actions you see are very likely executed out of knowledge but that person is not calmly exercising that knowledge – he is being motivated out of panic – and that is something that is beyond the control of the person. In fact, the dictionary definition of panic is “… a sudden sensation of fear which is so strong as to dominate or prevent reason and logical thinking, replacing it with overwhelming feelings of anxiety and frantic agitation consistent with an animalistic fight-or-flight reaction.” To me, this is what I think that F/O was doing ... reacting with a skill set and doing so out of panic ... attempting to function without thinking logically or reasoning to any degree and was, instead, functioning out of an overwhelming feeling of anxiety and frantic agitation.

roulishollandais

6th Oct 2013, 19:40

@Owain Glyndwr
Dutch roll is certainly an oscillation, but it doesn't have to be one of increasing bank; in fact it would be a lousy aircraft for which that were true - very probably unflyable. Increasing bank as a result of suitably (mis)timed pilot inputs is quite another thing.

Sure the rolling motion is usually the most obvious sign of a dutch roll, but the motion is a combination of two oscillations -one around the roll axis and the other around the yaw - linked together by a common driver - sideslip.

Way back in the 1950s Ashkenas and McRuer established the importance of the roll/sideslip ratio as a parameter to describe the goodness/badness of dutch roll. The larger the number the worse the aircraft basically. So dutch roll can be triggered by rudder application, but as you say it is best controlled by aileron.

So far as I know, the A300 was not noted as having poor dutch roll characteristics.
I am holding that resonance definition of "dutch roll" from my automation teacher, an engineer working at the last French projects.

Iself had read conventional things about dutch roll in ATPL books but was interested by real dutch roll since 1979 from a Learjet Captain who feared it during any approach. I read and listening again.

And it happened that I decided to study automation after a background of pure and applied math, scientific informatik, and aeronautics.
One day (1985) the teacher resumed about stable/unstable systems : You know, phase planes, Lyapounov, Nyquist, Bode, sign of real part of poles, aso. And suddenly he had a thought, stopped one second, and said "Dutch roll is resonance tween the first degree system of roll of the aircraft, and action of pilot....

He ignored that at least one student from around 30 was concerned by dutch roll!
He came back to the class concerns, but the sentence was printed in my brain. I had not seen the learjet's or books' "dutch roll" in these terms. So I did nothing more during years with that declaration, despite all the respect I had for my teacher.

In my airline a MD 83 had in 1992 a dutch roll approaching NICE 05. They were very mute about it (well finished over the sea, the Captain leaved controls as he had learned as Cadet in USA. But the Airline head decided to let us discover the pleasures of dutch roll during the next off-line sim test. Nobody said they had all failed before me and I was the last one. The instructor was a former business pilot on Learjet! The first pilot started and lost 11000', we went on the back right and left... At the end the instructor said him very sad "You have seen it".

It was now to me. Suddenly I reminded to my automation teacher, and I thought that if "dutch roll" accorded to HIS definition, I could perhaps try to get it. I showed the animal,his position, speed, acceleration, counted seconds in my head, reckoned two easy differential equations in my head and piloted the result (nothing to do with the above B727 rolls described method).

And five times ago I was able to stop the "dutch roll" (in the sense of my former learjet instructor and the books) with a bank which was never more than 30°, in less than 30seconds, and never lost more than 1000 ft.

In my airline nobody asked me my method, included the instructor and the second pilot... Very sad,

I wrote it only in 1997 after I discovered that one of my former private pilot student had been killed as passenger from the Learjet which killed Baroin Sr perhaps in a dutch roll degenerating in a deepstall.Sad again.

I phoned to Leadair (LFPB) and finaly Learjet in Geneve (1998) . I told my story to the Chief Pilot, who answered they had finaly found a methodcagainst Leajet's dutch roll : ...sharing quickly the pedals... I asked me how it was possible to imagine that sequence.

On PPRuNe more recently I discovered that dutch roll was considered as a unworthy situation.

Machinbird who had written about PIO in the AF447 thread suggested me to read Mc Ruer's book about PIO and other APC.

I found there a world I had not found in aviation until that day : scientific methods and true solutions in the continuous and discontinuous domains of FBW and classical flights including the often missed rate limitations, omnipresent in FBW systems leading to oscillation (I don't remember mention in the FBW thread).

So I stay with my teacher's definition of dutch roll. I don't deny the roll and yaw reciprocity which conduced to the yaw damper conception, present on all airliners of course.

The failure of the yaw damper is the first cause of dutch roll or aggravated roll and yaw oscillations. If the pilot is not able to stop them quickly which is the most frequent case, the bank will really increase, also in the case where we still are in a first degree system in resonance with pilot's "normal" inputs...

About the stability of the "A300", the APA document refered by misd-agin is not so optimistic with the "FBW" technology version of the A300-600R. In any case iit needs its yaw-damper is functionning.

To mention too the sudden impulsion of yaw damper failure, and once again any brutality in piloting like quick reversals on rudder...

For the defense of some aircrafts major manufacturors I would like to remind that oscillation computation means are relatively recent.

AirRabbit

6th Oct 2013, 19:52

I am going to have to get into an Airbus sim...

Slow flight, departure stalls, stall spin recoveries, wake turbulance, microbursts...

Probably all I will hear from the back of the sim...

'yeah, um, gee, try not to use the rudder to much...yeah I know the wings were 90 degrees and the plane was going to roll on it's back, but you know, um, well, gee, you see the tail hydros are really sensitive, and the tail, well, um, gosh, you see, well, the NTSB says the plane will right itself..oh, yeah, I know you were going to hit the ground, but you know, um, well, gosh, that's the recomendation, um, well, yeah, uh huh...'.

This probably has to be the most stupid conversaton on an aviation forum I have ever been part of.

It is apparent that you’ve likely never spent much time in a transport category airplane simulator – I would LOVE to hear about your “departure stall” and “stall-spin-recovery” maneuvers that you’ve done in simulators previously and that leaves me to wonder why the only “conversations on an aviation forum” that are stupid are those in which you have “been a part.”

AirRabbit

6th Oct 2013, 20:08

Quote:
Originally Posted by tdracer
So, Teldorserious, how do you explain that in the aftermath of the crash, Boeing structural engineers did the same analysis and came up with the same answer - that the same rudder inputs would have failed the tail on a Boeing aircraft?
Or along the same lines, how do you explain that even before the AA crash, Boein issued an amendment to the Operating Manual of the KC-135 stating that reversals of rudder application can cause the vertical stabilizer to fail. (previously posted in this thread)

Having my own membership card in the “professional gas-passers union” (active in the late 1960s through the early 1970s) I can say that, while the Ops Manual didn’t have a specific note in the text, a flight crew member couldn’t get through the “ground school” classes taught at Castle AFB without hearing (and I think my eardrums are still scarred) about the effectiveness of the rudder on that airplane, and how virtually ANY movement of it (powered or unpowered) was to be VERY sparingly used … and NEVER reversed!!!

john_tullamarine

6th Oct 2013, 20:49

I note that some of our number have concerns with a particular poster.

Rules of the forum are that we tolerate outlier posts while they reasonably don't go against the forum policies.

My suggestion is that those folks with a concern ignore such posts.

In the background, however, I shall monitor ...

tubby linton

6th Oct 2013, 21:02

I have flown the A306 for almost twenty years and never had a handling problem with it. My employer has flown it since 1990 and we have never had the prolems or incidents that AA had with theirs.I have flown a number of Boeing types and Airbus FBW and I would say that the nicest one to handfly was the A306 with the B757 the worst. The only time I had a problem with rudder on the 306 was an incident where we had an iced up pitot . This affected ADC1 and the aircraft was putting in huge amounts of rudder as it tried to co-ordinate turns as it thought it was flying at 80kt or less when in fact we were at Mn0.78.

flarepilot

6th Oct 2013, 21:11

I hope this thread ends with this post.

1. some people knew the plane's rudder would cause this to happen if ''reversed'', some didn't know. The real question and problem is why didn't the line pilots know? (and don't say they should have known, that's just a dopey excuse, like you should have known if you married ethel her cooking would give you gas)

2. Doing my bit of research, the US government was quite concerned over the role many interested parties had in trying (repeat, trying) to influence the outcome of the NTSB probable cause. Were there attempts to influence? Yes. Did they influence the final report...you decide.

3. The FAA has in the past known about problems with certain planes in certain conditions and have not passed the information along to the users of the planes. I can remember especially the problem with the F28 Fokker and so called ''hard wing planes''. An accident in Canada showed the problem and it was repeated three years later in the US...oops, the FAA forgot to tell the users.

4. There has been more than enough hatred on this thread as to ruin the bond we share in the sky. Claims and counter claims of experience and the like. One recent one about departure stalls in a transport category airplane sim really got to me. We did departure stalls in our douglas, mimicking a takeoff without proper flaps/slats, akin to the tragedy in Detroit many years ago...we called them departure stalls. We also did stalls in the approach/landing configuration and called them approach to landing stalls. We also did stalls in the clean configuration.

Don't attempt to pontificate on what airlines own wording is about unless you have flown for all airlines or approved their training programs.

Lessons that should be learned from this crash.

Engineers should think like pilots and make safeguards of every conceivable type to protect pilots from killing people.

Pilots should think like engineers and know that very few planes are as strong as pilots think they should be.

The FAA better make darn sure everyone knows more about their planes and that training and examination proves everyone knows.

And we better all know that flying can still kill you and those you are charged with protecting. Suffice to say, you should fly like a little old lady to stay out of trouble, but once you are in trouble fly like a tiger to get out...but be careful if you have a tiger by the TAIL.

And wake turbulence does kill, it caused a crash many years about (about 40) .

There may be unknown problems with you or your plane...be alert...I still think of the tragic loss with rudder hardover on the 737 as a great example...be ready, esp below FL180.

NOw, quit talking about this please

bubbers44

6th Oct 2013, 21:39

The B757 was my favorite airplanes to handfly. It flew beautifully into our most challenging airports. I loved it. It never gave me any surprises. It outperformed all of the other airliners I flew by far.

PJ2

6th Oct 2013, 21:46

AR, re, "I’m describing the ability to not react out of panic, but rather function as you have been trained, choosing what your reaction will be – and I’ve described this in pilots as being somethink like …'scan – mentally process – feel – mentally process – scan – mentally choose a response – physically respond – scan – mentally process – feel the motion – visually confirm the motion cue – mentally process – etc.' "

Quite well put, really.

Words describing this process such as "recursive" are for me, helpful but essentially it's the same thing - constant re-evaluation of 'things' on a second-by-second basis, with calm. There really aren't very many issues/abnormals/emergencies in transport aircraft that one must instantly react/respond to at a "basal" level, so to speak.

The best thing to do in AF447's case was as you describe and then "do nothing", (which meant just keep everything the way it was because neither the airplane nor the engines care about a loss of speed indication; the energy is still there, the stable cruise flight at one altitude is there, so "do nothing" - monitor, wait, call for ECAM, etc, maintain discipline).

Likely the UAS event they experienced would have been over in less than two minutes and they'd have had a serviceable indication and as others have pointed out, a log-book entry.

Further to the point, this is what training is all about - to handle the so-called "startle factor", (I can't believe that our industry actually believes in such nonsense, but giving the notion a broad and generous interpretation, perhaps that's what automation and not staying in the books engenders in pilots who may not know their airplane sufficiently well?)

bubbers44

6th Oct 2013, 22:01

I can't remember an airliner wake turbulence crash since wake turbulence at best May have caused some control changes before separation of AA tail but wasn't the cause. SNA had a corporate jet crash behind an airliner landing about 20 years ago caused by wake turbulence. Pilots should be able to handle it with experience.

Turbine D

6th Oct 2013, 22:49

Original Quotes by flarepilot:
NOw, quit talking about this please
Not so fast!
Lessons that should be learned from this crash.
#1. Just because you drive a Cadillac doesn't mean you can't have a wreck.
Engineers should think like pilots and make safeguards of every conceivable type to protect pilots from killing people.
Being an engineer, I think aircraft designers and propulsion engineers do a reasonable job at incorporating safeguards of every conceivable types reasonably expected, trouble is new unreasonably types keep being invented.
Pilots should think like engineers and know that very few planes are as strong as pilots think they should be.
Everyone should know that if you cycle something back and forth often enough and rapidly enough it will eventually break, it is called fatigue determined by the severity of the forces generated during the cycling and how many times it was cycled.
The FAA better make darn sure everyone knows more about their planes and that training and examination proves everyone knows.
Don't you think the airlines and their pilot training organizations have more of the responsibility for this? It seems to me those closest to the issues play the biggest role and bear the most responsibility. Organizations like the FAA tend to be recorders of input and history and whatever they record is dependent on input from the front line players. Perhaps learning of aircraft automation in training today has displaced basic learning of how the airplane actually works (minus the automation) with less emphasis on the dos and don't when it is required, that is, when the autos drop out and you have to hand fly.

Lord Spandex Masher

6th Oct 2013, 22:52

Engineers should think like pilots and make safeguards of every conceivable type to protect pilots from killing people.

They have. It's called a tank and doesn't fly...it's pretty robust though and won't fall apart if you waggle the controls.

AirRabbit

6th Oct 2013, 23:19

I hope this thread ends with this post.
Well, I was hopeful that we could … but … I kept reading further …

Some people knew the plane's rudder would cause this to happen if ''reversed'', some didn't know. The real question and problem is why didn't the line pilots know? (and don't say they should have known, that's just a dopey excuse, like you should have known if you married ethel her cooking would give you gas)
I agree with you that the question you pose is proper and should be answered. If one were to look at the regulations with respect to what has to go into a training program, you should find that among other things is the necessity to include the Airplane Flight Manual in that education. Now, the issue would become, what MUST the manufacturer place into that AFM? If it included information about flight controls, and the airplane was susceptible to losing some/all of the tail structure with rapid rudder inputs/reversals, it should be clearly noted. Perhaps someone should demand that the regulator (all the regulators, actually) take another look at this requirement and how it is fulfilled.

Doing my bit of research, the US government was quite concerned over the role many interested parties had in trying (repeat, trying) to influence the outcome of the NTSB probable cause. Were there attempts to influence? Yes. Did they influence the final report...you decide.
Any time there is an accident that has considerable consequences there are always persons who make some level of attempt to influence, or ask premature questions as suggestions, or drop other such subtle hints … and I have “first-hand” knowledge of such occurrences. (more on this privately, if you'd like)

The FAA has in the past known about problems with certain planes in certain conditions and have not passed the information along to the users of the planes. I can remember especially the problem with the F28 Fokker and so called ''hard wing planes''. An accident in Canada showed the problem and it was repeated three years later in the US...oops, the FAA forgot to tell the users.
If this is factual and if the FAA had such knowledge and did not provide it to the appropriate interested persons after verifying its accuracy … I would support a public riot in front of 800 Independence Avenue in Washington.

There has been more than enough hatred on this thread as to ruin the bond we share in the sky. Claims and counter claims of experience and the like. One recent one about departure stalls in a transport category airplane sim really got to me. We did departure stalls in our douglas, mimicking a takeoff without proper flaps/slats, akin to the tragedy in Detroit many years ago...we called them departure stalls. We also did stalls in the approach/landing configuration and called them approach to landing stalls. We also did stalls in the clean configuration.

Don't attempt to pontificate on what airlines own wording is about unless you have flown for all airlines or approved their training programs.
This is probably the section that garnered the most of my interest for responding … you say you did “departure stalls” and “approach to landing stalls” and you mentioned accomplishing “clean configuration stalls” as well and because of the discussions, I am presuming you mean that you did these stalls in the Airplane Flight Simulator. I am curious – were these simulators of the older or newer versions – and for timing era reference … the older simulators I’m describing were “Pre-1980,” the newer versions are Mid-1980s, and the most modern were built after about 2005.

The specific question has to do with motion and visual system installations and, specifically, the flight data and engine data packages that were incorporated. My guess is that what you did in the simulator was likely “recovery from approaches to stall” as opposed to “recovery from an aerodynamic stall” as this was the requirement when done in the airplane – and there was no requirement to do more in the simulator than was done in the airplane … and, there wasn’t much objection because everyone understood, rather completely, that the recovery from an aerodynamic stall in a simulator could not be simulated with any degree of accuracy. So, as recovery from an approach to stall in the simulator would be only slightly different from recovering from an approach to stall in an airplane, authorizing this in a simulator seemed to be acceptable. The minor problem was that the simulator handling and performance conclusions were based on somewhat limited aerodynamic information gained from flight testing and programmed into the simulator computer. The major problem was that the response of the turbine/jet engines were not tested at approach to stall angles of attack nor for stall angles of attack, and it is suspicioned that data for the differences that would make either do not exist, or exist in only limited cases for limited applications. Therefore, these data are not incorporated into the simulator's computers. This came to light quite significantly in the analysis of the Airborne Express DC-8 accident, in Narrows, Va.

It has only been within the past 18 months that an effort, led by the FAA’s Chief Scientific and Technical Advisor for Flight Simulation, in coordination with the International Civil Aviation Organization and the Royal Aeronautical Society, using the Boeing Company, Bihrle Applied Research Inc., and CAE Electonics, Ltd., has a reasonable aerodynamic model been drafted, produced, and minimally researched as being minimally effective in full stall maneuvers in the most advanced simulator available in today’s market. This model has not been finalized nor released for system wide application.

The FAA better make darn sure everyone knows more about their planes and that training and examination proves everyone knows.
From your lips to God’s ear.

NOw, quit talking about this please
Well …?

A Squared

7th Oct 2013, 03:26

Having my own membership card in the “professional gas-passers union” (active in the late 1960s through the early 1970s) I can say that, while the Ops Manual didn’t have a specific note in the text, a flight crew member couldn’t get through the “ground school” classes taught at Castle AFB without hearing (and I think my eardrums are still scarred) about the effectiveness of the rudder on that airplane, and how virtually ANY movement of it (powered or unpowered) was to be VERY sparingly used … and NEVER reversed!!!

I guess you missed my post in which I posted an excerpt from the revision to the KC-135 Dash one, which said exactly that. I even posted the issue date, which, being 30 June 2000, would have been after you were no longer flying that airplane (But well before the AA587 crash)

Here's a link to that document. (http://dms.ntsb.gov/public%2F32500-32999%2F32764%2F241728.pdf)

I think we agree here on the larger question, you're just mistaken in claiming my specific information is inaccurate.

Brian Abraham

7th Oct 2013, 06:07

The FAR 25 spells out quite clearly, should it be read, the design standard of the rudder with respect to Va. Quite clearly our educational system is lacking. I certainly did'nt appreciate the fact until this accident.

Teldiserious, you may claim I'm a troll, and as you have done in Biz Jets, a liar. The latter claim opens you to legal proceedings should I decide to go down that route.

JT, I don't envy your job.

Machinbird

7th Oct 2013, 07:17

Others have mentioned resonance as a cause for the AA587 and that was the cause in my estimation. It was not resonance of the vertical stabilizer that some here may have imagined causing the vertical stabilizer to break off, but instead, the entire aircraft oscillating in yaw around its vertical axis.

This oscillation reached an amplitude that you could never generate with a single application of full rudder. Instead it built upon the energy of preceding oscillations until the combined effect of all the oscillations plus increased angle of attack of the vertical stabilizer/rudder combination as the rudder reversed broke the vert stabilizer.

A resonant structural oscillation looks like this:
http://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Resonance.PNG/800px-Resonance.PNG

Most of my flight time has been in what are now considered old jets with irreversible hydraulically powered controls that were connected to the stick and rudder pedals by cables and pushrods.
With irreversible controls, you do not have a clue to the forces you are exerting unless you have some sort of feedback. One rather fast aircraft that I flew used artificial feedback and changed its rudder pedal force from 2.6 lbs force/degree of travel to 11.5 lbs force/degree of travel at about 225 kt by means of an airspeed switch and a hydraulic centering cylinder. It then used the higher pedal force all the way up to its limit speed which exceeded M 2.0. The engineers were not at all concerned about us breaking the tail at that higher force ratio, but there were warnings to avoid excessive rudder deflection should the airspeed switch fail to work properly. Full travel of the rudder and rudder pedals was not restricted on that aircraft, but it was essentially impossible to exceed the intended rudder travel limits.

On the A306, the variable rudder travel limits protect the aircraft against a single rudder input overstress. Unfortunately, that system was not (and is still not) able to protect against an oscillatory rudder input where the input frequency approaches the natural tail wagging frequency of the aircraft. This system is also a mechanically controlled ,irreversible, hydraulic powered flight control with artificial feel. The problem is that the force and travel required to activate the rudder to its limits were minimal, and thus it was easy to excite a yaw oscillation by relatively small repetitive rudder inputs. Not the best design, but now that everyone is aware of the hazard, it is unlikely to bite again.

Incidentally, the simcrash posted by SMOC was almost certainly caused by resonance with the natural frequency of the simulator on its base.
http://virtualmystic.files.wordpress.com/2008/06/simcrash.jpg
This could then have been prevented by a software change to attenuate near-resonant frequency inputs.

Owain Glyndwr

7th Oct 2013, 08:02

Hi roulis

I am holding that resonance definition of "dutch roll" from my automation teacher, an engineer working at the last French projects.Whilst I hold to that I got from my professor and all the reports I read on the subject as a young man!

Look roulis, this is mainly semantics and I don't wish to prolong the debate. I learned a long time ago that if you express your arguments in a firework display of Greek letters and differential equations then 95% of your audience will not understand you and the other 5% will not believe you, so let me say my piece once in plain English and then go back to lurking.

All aircraft have a dutch roll mode but not all aircraft have a dutch roll problem.

Lateral stability has three parts (OK, solutions to the equations of motion if you must ...)
a) Roll damping - always a subsidence
b) Spiral stability - either a subsidence or a divergence but never an oscillation
c) Dutch roll oscillation which may be damped or undamped; described by three parameters - frequency, damping and roll/sideslip ratio.

All of these are excited by manoeuvering the aircraft or by turbulence.

And suddenly he had a thought, stopped one second, and said "Dutch roll is resonance tween the first degree system of roll of the aircraft, and action of pilot....There I think he was wrong, if only because one can't get resonance in a mode with only one degree of freedom. Dutch roll is an oscillation that can be, and is, triggered by sideslip with no pilot action necessary.

If the dutch roll is well damped then there is no problem, but if not and particularly if the roll/sideslip ratio is high then if turn coordination is not perfect applying aileron can start off an oscillation which yes, does affect the roll response. In extreme cases it can generate a hesitation or even a partial reversal in the bank angle response. At high AoA if the aircraft rotates around the fuselage axis then sideslip may be generated anyway unless some rudder is applied at the same time.

In other cases it becomes difficult to maintain straight and level flight.

I showed the animal,his position, speed, acceleration, counted seconds in my head, reckoned two easy differential equations in my head and piloted the result (nothing to do with the above B727 rolls described method).

And five times ago I was able to stop the "dutch roll" (in the sense of my former learjet instructor and the books) with a bank which was never more than 30°, in less than 30seconds, and never lost more than 1000 ft.If you can solve two differential equations in your head whilst at the same time flying an airplane then you are a better man than I :D But in the end, were you doing any more than applying the process that Chris Scott (I think) described earlier - applying corrective aileron at the correct time in the roll?

Machinbird who had written about PIO in the AF447 thread suggested me to read Mc Ruer's book about PIO and other APC.
Yeah - all good stuff isn't it

So I stay with my teacher's definition of dutch roll. I don't deny the roll and yaw reciprocity which conduced to the yaw damper conception, present on all airliners of course.And I will stay with mine, but as I said it is mostly semantics

The failure of the yaw damper is the first cause of dutch roll or aggravated roll and yaw oscillations. If the pilot is not able to stop them quickly which is the most frequent case, the bank will really increase, also in the case where we still are in a first degree system in resonance with pilot's "normal" inputs...Like I said, no resonance in first degree systems....

About the stability of the "A300", the APA document refered by misd-agin is not so optimistic with the "FBW" technology version of the A300-600R. In any case iit needs its yaw-damper is functionning.Errrr - what FBW technology on the A300?

For the defense of some aircrafts major manufacturors I would like to remind that oscillation computation means are relatively recent. Well we didn't have today's computing power, but we were calculating dutch roll contributions to lateral behaviour half a century ago :ok:

Chris Scott

7th Oct 2013, 09:35

Owain Glyndwr, replying to roulishollandais (dutch roll):
...were you doing any more than applying the process that Chris Scott (I think) described earlier - applying corrective aileron at the correct time in the roll?

For those who didn't see it, there was a recent Tech Log thread entitled "Mystery of Yaw Damper", which is worth a read in the context of dutch roll. This is the post OG is referring to, and provides a quick link to that thread -

http://www.pprune.org/tech-log/522527-mystery-yaw-damper-2.html#post8028984

On this thread, the robustness of the A306 VS/fin has been regularly called into question by a minority of New-Worlders, whose patriotism blinds them to the fact that - since the pioneering Comet 1 disasters - European airframes have a record at least as good as their American counterparts. This misconception was characteristic also of all our AF447 discussions, specifically in relation to the integrity of the A330 VS/fin.

The discussion between AirRabbit and A Squared have made me wonder afresh about the B707/KC-135 airframe. Here's part of an earlier post of mine, which failed to provoke a response:

Quote from tdracer:
"I don't seem to recall anyone ever claiming that the 707 airframe wasn't robust."
When I did my base training with AA at DFW in 1975, I was surprised that no attempt was made to demonstrate dutch roll characteristics and recovery at altitude, even though the a/c was equipped with only one yaw damper. (BTW, I'm not suggesting that dutch roll recovery by the pilot would involve any use of rudder.) Four years earlier, my VC10 conversion had included several full demonstrations (up to about 40 degrees of bank) and recovery. The VC10 has(d) 3 independent rudders, each with a yaw damper.
One possible interpretation was that the a/c was not inclined to serious dutch roll at altitude - we all know that it would on the approach. On reflection, I'm wondering if the B707 airframe, specifically the vertical surfaces, may have been merely adequate for the regs? Has anyone got a copy of Davies to hand?

Why do so many North Americans have such dumb confidence in the robustness of Boeing's products, and such a jaundiced perception of Airbus's?

Owain Glyndwr

7th Oct 2013, 11:27

Thanks for correcting my posting Chris - one loses track of who said what & where!

I'm wondering if the B707 airframe, specifically the vertical surfaces, may have been merely adequate for the regs? Has anyone got a copy of Davies to hand?Short answer: Davies doesn't mention structural capability so far as I can see. Boeing paper on use of rudder as published by IFALPA says that all Boeing aircraft meet the regs with a bit to spare, but don't say if that applies to just current range or to all designs past and present (KC135 excluded!)

Davies has quite a bit to say about dutch roll and recovery therefrom, also some interesting remarks on rudder bar travel cfd rudder angle. (p263 in my 1976 edition)

Brian Abraham

7th Oct 2013, 11:34

On the road at the moment so don't have access to the library, but Davies was the certification pilot for the 707 in the UK. He refused to give it a tick until Boeing did something about the fin/rudder. Forget the exact details of the issue to hand.

Owain Glyndwr

7th Oct 2013, 13:02

Brian

IIRC it was to add a bit of fin area (ventral fin?) Mystery of the Yaw Damper thread again I think refers

Hobo

7th Oct 2013, 14:12

Having once flown a 707 all the way LHR-BDA with a yaw damper and autopilot that would not engage and encountered light and moderate turbulence several times on the flight, I would never accept a 707/737 without a working yaw damper. The dutch roll (corrected by roll inputs only) was most unpleasant for the pax, these were the days before modern flight recorders, but IIRC we got to 45 bank on several occasions.

PJ2

7th Oct 2013, 14:22

Hi Chris, OG, Brian, others;

A thoroughly worthwhile (continuing!) discussion in my view.

Brian I recall the ventral fin "addition" on the B707 when building models (Revell) of the aircraft as a kid. There was a time when it didn't have it. I think too, it was on the B720. I ran across this comment in Tech Log from "411A (http://www.pprune.org/tech-log/362736-boeing-707-ventral-fin-story.html)": Ventral fins were required during US certification to provide greater yaw stability...they came in two sizes, 13 inch and 39 inch, and were eliminated on later aircraft when the vertical stabilizer height was increased.
Note also that all aircraft that had ventral fins installed also had parallel type yaw dampers as standard fit.

AirRabbit

7th Oct 2013, 16:23

I guess you missed my post in which I posted an excerpt from the revision to the KC-135 Dash one, which said exactly that. I even posted the issue date, which, being 30 June 2000, would have been after you were no longer flying that airplane (But well before the AA587 crash)

I think we agree here on the larger question, you're just mistaken in claiming my specific information is inaccurate.

Please accept my most humble apologies A Squared … my intent was not at all intended to say that your information was inaccurate … I was simply pointing out that long before the revision you cited was made to the manual, there was universal understanding among the tanker crews that the barn door on the back was something that deserved the greatest respect! And it’s nice to know that other members of that particular union participate in this forum! Welcome aboard!

A Squared

7th Oct 2013, 16:31

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.

con-pilot

7th Oct 2013, 17:00

This has happend before.

http://www.talkingproud.us/Military/B52%20No%20Tail/files/b52notail.jpg

B-52 with no tail - YouTube

roulishollandais

7th Oct 2013, 17:03

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 ?

Owain Glyndwr

7th Oct 2013, 17:18

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.

AirRabbit

7th Oct 2013, 17:34

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.

733driver

7th Oct 2013, 18:41

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)

Chris Scott

7th Oct 2013, 20:31

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?

bubbers44

8th Oct 2013, 01:44

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.

tdracer

8th Oct 2013, 03:13

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" :ugh:

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 :mad: 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 :sad:. 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 :uhoh:

bubbers44

8th Oct 2013, 04:42

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.

Brian Abraham

8th Oct 2013, 05:57

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.

Owain Glyndwr

8th Oct 2013, 06:42

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.

PJ2

8th Oct 2013, 06:56

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 (http://www.boeing.com/assets/pdf/news/techissues/pdf/statsum.pdf) (1959 - 2012) speaks for itself because the numbers are available to anyone.

The key, as we who actually do (or did, :sad:) 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.

Chris Scott

8th Oct 2013, 15:02

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?

DozyWannabe

8th Oct 2013, 15:11

...is in deeply knowing one's airplane

Presumably not in the Biblical sense though - that would just be wrong! :E

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!

PJ2

8th Oct 2013, 15:51

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.

DozyWannabe

8th Oct 2013, 16:36

@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. :8

roulishollandais

8th Oct 2013, 17:10

@ 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.:ok:

AirRabbit

8th Oct 2013, 22:15

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.

DozyWannabe

8th Oct 2013, 22:52

Do you keep that correspondence with your "Certificate of Awesome" signed by Neil Armstrong and Chuck Yeager? :rolleyes:

Linktrained

9th Oct 2013, 00:19

Horatio Barber, who flew the first aeroplane freight (Osram bulbs), wrote
"The Aeroplane Speaks"
for pilots and trainee pilots of the Royal Flying Corps in 1917. (It can be downloaded for those interested in what was taught, then.. Perhaps a HTBJ of its day.)

bubbers44

9th Oct 2013, 03:22

I have talked to and seen Bob Hoover several times and what a gentleman. Reading his book he would have had the sound barrier record if he hadn't done a buzz job that pissed off the commander so Chuck Yeager got it.

They have been at the Reno Air races the last 13 years I have been there and have Bob Hoovers autograph on his book. He used to fly into Flabob Airport in Riverside Ca. to see Art Scholl who I flew aerobatic instruction for and always landed his Shrike on one wheel even if nobody was looking. It was great flying back then. Everybody knew how to handfly and autopilots were a luxury but no one needed one. Today is different for the new people. We need to make new pilots real pilots not programers. Bottom dollar thinking probably won't let this happen again.

tdracer

9th Oct 2013, 04:42

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.

While 'posers' can present a problem, limiting to actual pilots would seriously limit valuable inputs and different points of view. I make no secret that I'm not a pilot (although I would have liked to be, and nearly was - but that's another story). But I do have 36 plus years experience as an engineer in Boeing Commercial Aircraft - working at one time or another 727, 737, 747, 757, 767, and 777. In short, I know a lot about 'how planes work' (at least Boeing planes), and I'd like to think that knowledge brings something valuable to the discussions. Unfortunately I often have to censor myself, because I know things that I'm not allowed to make public. Oftentimes it's considered Boeing proprietary/sensitive, in the case of air safety investigations we can get in big trouble for releasing unauthorized information before the official stuff comes out (e.g. I know stuff about Asiana that I can't repeat).

I also value the pilots input on what we do. I've known and worked with lots of Boeing test pilots over the years - some well known, others not so much - but getting input from the guys (and gals) that fly these planes on a day to day basis has a special value.

Brian Abraham

9th Oct 2013, 06:33

Dozy, I may very well be in error but I have reasons to believe flarepilot may very well be a reincarnation of our friend SSG, lately going by the Teldorserious handle. Flarepilot made the claim earlier in this thread that the Sabreliner 40 had a placard in the cockpit advising limiting control movement to 50% when above 40,000 feet. Only trouble is the operators of the aircraft I've talked to have never heard of it, and nor the FAA.

john_tullamarine

9th Oct 2013, 07:03

But I do have 36 plus years experience as an engineer in Boeing Commercial Aircraft

.. which is why we don't have an exclusive pilots' club and warmly welcome folks such as your goodself to the sand pit.

roulishollandais

9th Oct 2013, 08:47

I know things that I'm not allowed to make public. Oftentimes it's considered [X] proprietary/sensitive, in the case of air safety investigations Could these things kill again?:}

Clandestino

9th Oct 2013, 09:41

Doesn't matter if it behaves differently, it's still the same system. Depends on one's agenda; if one believes that main lessons of AA587 are: never use rudder for roll when yoke is more than enough and never rapidly cycle any control as it is completely useless and potentially lethal, then differences in breakout force and force gradient between two principally similar systems are really moot point. Now if one wants to malign A300 and perhaps even complete Airbus range, than this difference really must be blown out of all proportions.

It gives me the chills when I feel it, and I am forced to ask what are the type-rating trainers and the line trainers up to by allowing this crass, clumsy and careless handling? Up to what is written in manuals and not a bit more. Be gentle to your aeroplane as much as you can so you can be tough to her when things get hairy without fear of breaking anything due to accumulated fatigue? Naaah, not in training manual.

Not only was the subject not delicate, but there were some mil airplanes that 'required' aggressive (but smooth) use of rudder in some flight regimes. One of which had been flown extensively in the 80s by many airline captains of the 90s.Rhino?

To me, this is what I think that F/O was doing ... reacting with a skill set and doing so out of panic ... attempting to function without thinking logically or reasoning to any degree and was, instead, functioning out of an overwhelming feeling of anxiety and frantic agitation. I'm afraid I agree with this one. Seemingly he firmly believed his actions were appropriate without stopping and checking whether they really were.

I hope this thread ends with this post.Given the quality of arguments in it, no surprise it turned out to be self-defeating prophecy.

The real question and problem is why didn't the line pilots know?Insufficient basic knowledge. One can have long and successful even while being pretty ignorant or even very wrong about some basic aeronautical facts. Pilot who thinks rudder is always used to deal with wake vortex just needs to avoid wake vortices.

Doing my bit of research, the US government was quite concerned over the role many interested parties had in trying (repeat, trying) to influence the outcome of the NTSB probable cause. Were there attempts to influence? Yes. Did they influence the final report...you decide.Completely unsubstantiated claim.

The FAA has in the past known about problems with certain planes in certain conditions and have not passed the information along to the users of the planes. I can remember especially the problem with the F28 Fokker and so called ''hard wing planes''. An accident in Canada showed the problem and it was repeated three years later in the US...oops, the FAA forgot to tell the users. Complete and utter lie. Slatless aeroplanes have no problems when de-iced properly. Whoever believed this paranoid rant would be severely mislead.

There has been more than enough hatred on this thread as to ruin the bond we share in the skyThis appeal to emotions sucks at large. I do hate the people who try to pervert the lessons that should be learnt form demise of our colleagues as it increases the risk of the same crash happening again.

Engineers should think like pilots and make safeguards of every conceivable type to protect pilots from killing people.Completely unrealistic target. There is a limit in making aeroplanes fool-proof and safeguard under one condition can easily turn out to be lethal under other.

Just ask usual contributors about evils of envelope protection :E or if more realistically inclined, read DP Davies treatise on stick pushers.

The problem is that the force and travel required to activate the rudder to its limits were minimal, and thus it was easy to excite a yaw oscillation by relatively small repetitive rudder inputs.Makes me wonder if it was so easy, why did the unlucky F/O bother with exerting 140 lbs push?

Sheer panic.

A recent thread said the B787 is designed to be able to be flown by equally incompetent Airbus pilots because of it's automation. Misunderstanding, as it is usual on PPRuNe. FBW protection can stop distracted pilot from getting the aeroplane into irrecoverable attitude but that's about it. Many times it was proven that one can stay well clear of protections and still wreck the aeroplane.

What we need is a new point of view that does not exist in our regulations of certification concerning RESONANCEI think you have misspelled "reason" there. Protection form resonance brought about by totally unnecessary and useless control inputs would have fallen afoul of this proposed regulation.

Chris Scott

9th Oct 2013, 10:45

Quotes from tdracer:
"I make no secret that I'm not a pilot (although I would have liked to be, and nearly was - but that's another story). But I do have 36 plus years experience as an engineer in Boeing Commercial Aircraft - working at one time or another 727, 737, 747, 757, 767, and 777. In short, I know a lot about 'how planes work' (at least Boeing planes), and I'd like to think that knowledge brings something valuable to the discussions."

Precisely the kind of input pilots need to challenge their assumptions.

"...I also value the pilots input on what we do. I've known and worked with lots of Boeing test pilots over the years - some well known, others not so much - but getting input from the guys (and gals) that fly these planes on a day to day basis has a special value."

Looking back at my unremarkable career, some of the most rewarding dialogues I had were with engineers. Some of them were grizzled flight-engineers, but right now I'm talking about ground engineers. Admittedly, in my case they were mainly line-maintenance people; except in my earlier days on conversion courses, when some of the guys teaching us a/c systems had been production engineers on the same a/c. They've all since been supplanted by CBT, and what the powers-that-be think we "need to know"; more's the pity.

"Unfortunately I often have to censor myself, because I know things that I'm not allowed to make public. Oftentimes it's considered Boeing proprietary/sensitive, in the case of air safety investigations we can get in big trouble for releasing unauthorized information before the official stuff comes out..."

roulishollandais (above) expresses the concerns of many of us, but I'm assuming that anything operators need to know urgently will be promulgated to them by the usual bulletins (senior moment: can't remember what they are called!). The only snag is that, in rare cases, the incident might not be manufacturer-specific. Operators of comparable a/c from a rival manufacturer might also need to be warned.

Speaking more generally about commercially sensitive information, there is a perception in British aviation circles that, in the past, efforts to share knowledge for mutual benefit have rarely been reciprocated by American manufacturers (without mentioning any names). It's a truism that the Brits have been better at coming up with new ideas than they are at producing something that sells in large numbers. That's why we think it's a bit rich when Boeing supporters fume about Airbus's sales successes.

Perhaps, in some after-life, all you Boeing and Airbus engineers - not to mention the Russians and all the others - will get together, realise how similar your aspirations and expertise are, and create even better aircraft. But that kind of cosy, utopian relationship is not, admittedly, what got Apollo 11 to the Moon and back.

Owain Glyndwr

9th Oct 2013, 11:04

roulis

Pas d'accord! Well not entirely d'accord anyway.

and the pilot gives a second oscillation to try to stop the dutch roll "problem", starting resonance. My gripe is that the pilot giving a second oscillation is actually the problem since it is the pilot actions that in this case start off or aggravate the resonance.There are folks here that would think it presumptuous for a mere engineer, no matter how well qualified, to offer any advice on how to fly airplanes, but luckily Dave Davies has already done it, very concisely and very precisely:

The control of divergent dutch roll is not difficult so long as it is handled properly. Let us assume that your aeroplane develops a diverging dutch roll. The first thing to do is nothing - repeat nothing. Too many pilots have grabbed the aeroplane in a rush, done the wrong thing and made matters a lot worse. Don't worry about a few seconds delay because it won't get much worse in this time. Just watch the rolling motion and get the pattern fixed in your mind. Then, when you are good and ready, give one firm but gentle correction on the aileron control against the upcoming wing. Don't hold it on too long - just in and out - or you will spoil the effect. You have then, in one smooth controlled action, killed the biggest part of the roll. You will be left with a residual wiggle, which you can take out, still on ailerons alone, in your own time.

Don't attempt to correct the manoeuvre with rudder; as explained, the yaw is often suppressed and it is difficult to work out which way to apply the rudder at what particular moment and there is a good chance that the wrong rudder will be applied which will aggravate things very quickly. It is not difficult, however to apply the correct aileron control. Further, don't attempt to squash the dutch roll flat in one fell swoop but be content with taking out a big bite first time then sorting out the remainder next timeClearly, Davies at least regards the correct method as a type of open loop process. Note also his remarks on the difficulty of suppressing dutch roll oscillations by the use of rudder.

I know very well that if a pilot decides to actively control a dutch roll using aileron then unless he properly adapts his internal transfer function to match the open loop dynamics of the airframe there is a risk that at some value of pilot gain the root locus of the closed loop system might cross over into the negative damping region. [That piece of jargon ridden technological gobbledygook translates as "If the pilot tries to chase the dutch roll and gets his timing wrong he could end up in a PIO or APC situation"]

From what you have written this might have been the case on that Learjet?

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. Here I do disagree with you. The object of certification is to avoid any resonance not devise rules to tame it. In fact the existing regulations do just that:
§ 25.181 Dynamic stability.

(b) Any combined lateral-directional oscillations (“Dutch roll”) occurring between 1.13 VSR and maximum allowable speed appropriate to the configuration of the airplane must be positively damped with controls free, and must be controllable with normal use of the primary controls without requiring exceptional pilot skill.

Part 23, against which I believe that Learjet to be certificated, is slightly different :

§ 23.181 Dynamic stability.

(b) Any combined lateral-directional oscillations (Dutch roll) occurring between the stalling speed and the maximum allowable speed (VFE , VLE , VN0 , VFC /MFC ) appropriate to the configuration of the airplane with the primary controls in both free and fixed position, must be damped to 1⁄10 amplitude in:
(1) Seven (7) cycles below 18,000 feet and
(2) Thirteen (13) cycles from 18,000 feet to the certified maximum altitude.

If that aeroplane was a susceptible to dutch roll problems as your posts suggest then it must be on the limit for certification surely? Arguing from that case to a need for another set of requirements strikes me as an extrapolation from the particular to the general - and rather like extrapolating from a single spot point, that is a dodgy process.

john_tullamarine

9th Oct 2013, 11:43

Speaking more generally about commercially sensitive information,

Which, I understand is why the Brits, doing the right thing with respect to the knowledge gained with the Comet problems ... basically were dudded by the 707 in short order ...

Machinbird

9th Oct 2013, 13:36

Quote:
Originally Posted by Machinbird
The problem is that the force and travel required to activate the rudder to its limits were minimal, and thus it was easy to excite a yaw oscillation by relatively small repetitive rudder inputs.

Makes me wonder if it was so easy, why did the unlucky F/O bother with exerting 140 lbs push?
If you will remember, it only took about 30 lbs of force to reach the limit at that speed-that isn't much at all.
He was attempting to get the rudder moved as quickly as possible and was trying to help it along :}.
Or perhaps he was just spooked by the extreme yaw.

Assuming they only have rudder position indications on the FDR and not force indications, the 140 lb estimate would come from rudder rate acceleration tests.

DozyWannabe

9th Oct 2013, 13:54

It's a truism that the Brits have been better at coming up with new ideas than they are at producing something that sells in large numbers.

Well, to be fair in civil terms the US had the edge in terms of airframe tech in the inter-war years. Lessons learned during the war meant that the UK held an edge in R&D by the early 1940s, which was shared with and bequeathed to the Airbus project in the 1970s - in part via the Concorde project.

While it's true that the R&D "sharing" with the US in the postwar years skewed decidedly one way - it's also true that due to political and business machinations it was as much the fault of the parties on this side of the Atlantic as anyone. Of course the main issue with the mass-production side of things was difference in size of the potential civil airliner market following the war. A populace undergoing an austerity drive was never going to be able to afford airline travel easily, whereas the postwar growth of the US economy - along with the sheer size of the country - meant that air travel was not only within the reach of more of the population, but became a practical necessity for many.

Anyways - an interesting subject, but off-topic. So I'll leave it there for now.

Brian Abraham

9th Oct 2013, 14:35

OK, flarepilot. Here is what a very highly experience aviator (and Saberliner 40 pilot) has to say re your Sabre 40 assertions.

Okay, I have to call BS on this statement:

Quote by flarepilot "Flying it very high by hand was the most demanding flying I've ever idone, but I got the hang of it."

All Sabres were a delight to fly by hand no matter the altitude. So he is one of the worse pilots that has ever flown one, or he is a liar. The only types aircraft I have flown that may have been easier to fly by hand regardless of the altitude, is the Falcon 50/900 series and the Lockheed Jetstar.

Also, the military version of the Sabre 40, the T-39 had no auto-pilot* and were flown single pilot by the US Air Force. Hardly something that they would allow in the "demandingy flying" aircraft that someone had ever flown. One other thing, the wing on the Sabreliners was essentially the same wing as on the F-86 and F-100, both of which had no auto-pilot and were obviously were single pilot aircraft.

So at this point, I believe that the question about the aileron restriction is immaterial. As with the statement of his that you posted, goes a long way of proving this guy a 'Walt'.

galaxy flyer

9th Oct 2013, 16:55

With 500 hours in the Hun and about the same in the Sabre 65, I'd agree that both are pleasant to handfly at any altitude. The Hun had its moments, but that comes with the environment of any TAC fighter. No such restriction in my memory, but who would use 50% of control authority at high altitude/high Mach anyway?

Clandestino

9th Oct 2013, 17:42

the industry changed its way of handling DE ICING and ANTI ICING over the F28. Sorry, you must have been chewing on something else.

Lie. Both Dryden and LaGuardia (Skopje and Pau too) accidents featured non-adherence to de-/anti-icing procedures so there was no reason to change them.

If you will remember, it only took about 30 lbs of force to reach the limit at that speed-that isn't much at all.True, but why using rudder at all? Why rapidly reversing it?

tdracer

9th Oct 2013, 17:48

Quote:
Originally Posted by tdracer
I know things that I'm not allowed to make public. Oftentimes it's considered [X] proprietary/sensitive, in the case of air safety investigations

Could these things kill again?http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/badteeth.gif

The are rules and procedures during an investigation regarding the release of information - for several reasons. As we noticed on the recent Asiana crash there is a certain media frenzy that occurs - release of information that has not been properly vetted can have far reaching effects (even if it's a joke about the pilots names :mad:). There can be potential liability concerns - releasing partial or out of context info could result in slander and lawsuits (I've been the target of a slander lawsuit - it's no fun even when you can document what you said was accurate). So there is a process to release information in a controlled manner via the investigating agency (e.g. NTSB in the US). If there is something that poses an imminent threat to other aircraft, then it's the responsibility of the investigating agency to make that information public so that appropriate measures can be taken.

After the 787 Heathrow fire, many on here where complaining that Boeing wasn't forthcoming with information - short answer is the manufacturer is effectively gagged during the investigation - ALL public information is supposed to come from the investigating agency. For Boeing to release information could have gotten them in big trouble.

I was involved in the investigation of the BA 777 that 'landed short' at Heathrow (I was in a Boeing Safety Review Board meeting on an unrelated subject when a co-working showed me a picture of the crashed 777 on his laptop and said 'just happened!' :sad:). Anyway, within about a week we had a pretty good idea that ice had blocked the fuel/oil heat exchanger. But it took a couple months to validate that theory (rig testing and the such). If we'd released information implicating the Trent fuel system, and that turned out to be wrong - there would have been hell to pay :yuk:. The good news is that the designers were able to work on the fix even before the cause had been firmly established.

Some of you certainly remember the fiasco after the Chicago DC-10 engine separation and crash - when everyone though it was because of a broken bolt instead of damaged structure?:ugh: It's certainly good to get information out quickly, but you need to make sure it's the correct information.:ok:

roulishollandais

9th Oct 2013, 17:59

Owain,
Well not entirely d'accord
I have really nothing against Davies formulation ! Thank you for quoting it here. The only thing I see in my method (perhaps Davies did it for himself but did not express it here) is to get quantification instead of global words which can be misunderstood by pilots who revendicate to be stupid...
My bold show the words I did quantify :
The control of divergent dutch roll is not difficult so long as it is handled properly. Let us assume that your aeroplane develops a diverging dutch roll. The first thing to do is nothing - repeat nothing. Too many pilots have grabbed the aeroplane in a rush, done the wrong thing and made matters a lot worse. Don't worry about a few seconds delay because it won't get much worse in this time. Just watch the rolling motion and get the pattern fixed in your mind. Then, when you are good and ready, give one firm but gentle correction on the aileron control against the upcoming wing. Don't hold it on too long - just in and out - or you will spoil the effect. You have then, in one smooth controlled action, killed the biggest part of the roll. You will be left with a residual wiggle, which you can take out, still on ailerons alone, in your own time.

Don't attempt to correct the manoeuvre with rudder; as explained, the yaw is often suppressed and it is difficult to work out which way to apply the rudder at what particular moment and there is a good chance that the wrong rudder will be applied which will aggravate things very quickly. It is not difficult, however to apply the correct aileron control. Further, don't attempt to squash the dutch roll flat in one fell swoop but be content with taking out a big bite first time then sorting out the remainder next time I am seeing too that Davies's method is a step by step method effectively as you said it it can be seen as on open loop action, mine is continuous in the closed loop.
When Davies says "watch the rolling motion", I do the same but quantifying. Despite Davies's lack of precision we both know that we must read in the beginning of the transient response the clue to start the correction before the transient part is finished. He does not suggest to the pilot to start asap the correction, but when he feel "good and ready". But I understand that prudent formulation and choice of Davies, so long as pilot don't want to reckon some precisions... :
I know very well that if a pilot decides to actively control a dutch roll using aileron then unless he properly adapts his internal transfer function to match the open loop dynamics of the airframe there is a risk that at some value of pilot gain the root locus of the closed loop system might cross over into the negative damping region. Exactly ! Probably my teacher had a sudden thought to that risk at the moment he was speaking of root locus and decided him to say his sentence.

It seems that Chris's method on B727 is Davies's one like but less developped in the formulation I found in the Yaw damper thread ?

Why did Learjet not adopt Davies's method and stay wrong with the rudder use, and reversal use, and brutality use ?

Stopping the bad divergent oscillation is not all : probably your aircraft wants to play it again ! that divergence had a cause, and watching the motion quantatively helps to fly safe at home avoiding a new divergence with your jammed yaw damper...

Here I do disagree with you. The object of certification is to avoid any resonance not devise rules to tame itThe final object of certification is to do the aircraft safe for the wanted use. Today we have to increase air safety despite crashes statistics are getting better. All the crashes which can be avoided have to get progressively suppressed. Changing certification rules can perhaps help, and if it should help why not try ? Perhaps it could improve the speed of information from engineers to pilots ?
Writing operational rules may sometimes be included in certification. I remember when Concorde has been built some people said the bang should not be listen on the continent, so it was not possible to certify it. But thinking that the sound energy was decreasing with distance finaly it could be certified if respecting operational rules like not focalising turns, and respecting some distance of the coasts, and determining quantitatively point at which Concorde should start acceleration to M 1.

john_tullamarine

9th Oct 2013, 20:40

Chaps, can we return once again to playing the ball rather than the player ?

galaxy flyer

9th Oct 2013, 22:33

The KAVP T-39 accident with Gen O'Malley and his wife had nothing to do with Sabre high altitude handling and everything with no anti-skid installed and risk analysis of the airport. Can't speak to the 40, but the 65 was docile everywhere. Bob Hoover, who did shows with it would agree.

The T-39s were typically flown by first assignment pilots out of UPT who had a better record in it than in the Lears that followed.

bubbers44

10th Oct 2013, 00:57

Clandestine, I am not as worried about Airbus systems as much as junior pilots with no experience never geting any real hands on flying experience. Some day they will need real hands on flying experience or it will a be repeat of AF 447. Our generations had to handfly and welcomed the challenge. I don't like where we are headed. Many others here don't either. None of us old school pilots were too concerned if everything went south because it was just an inconvenience, now it is turning into an emergency.

bubbers44

10th Oct 2013, 01:43

bubbers44

10th Oct 2013, 01:46

Of course if the auto pilot clicks off you need someone that knows how to hold an attitude and not just pull up.

galaxy flyer

10th Oct 2013, 02:01

flare pilot,

Yes, very different slat arrangement, it doesn't have slats. The 65 had a Raisbeck "supercritical" forward section grafted onto the basic wing. Super in "supercritical" meant one needed to be super careful in icing. Bit like the wing on the CL600 series--fine, if you followed the book in icing conditions. But, if the leading edge section had the least bit of contamination that created sonic flow, it stalled abruptly especially if a rapid rotation brought the wing to stall AOA in ground effect (IGE). Big steaming bowl of Not Good, see G650 accident and all the CL600 accidents. All abrupt, asymmetrical stalls IGE.

Brian Abraham

10th Oct 2013, 06:50

Playing the ball. Flare pilot, I'll quite happily eat crow if you can scan the relevant page from the flight manual and post here. I repeat SCAN the relevant page. Only because no one I've talked to has heard of it. Up to the challenge? Until then then.

Owain Glyndwr

10th Oct 2013, 08:20

roulis

But I understand that prudent formulation and choice of Davies, so long as pilot don't want to reckon some precisions... : I’m really not sure what point you are trying to make here. If it is a plea for a mathematical definition of acceptable dutch roll characteristics then such things already exist and are used by engineers in the design stage to establish whether yaw dampers are needed (almost always they are) and to define the control laws under which they will operate. Search for lateral directional handling criteria and you will get a bucketful. (or MIL-F-8785C)
If you are looking for something to use in flight then I think that would not be very practical; besides which I am sure that pilots don’t need a set of memorised numbers to tell them that the aircraft is doing something they don’t like!

Why did Learjet not adopt Davies's method and stay wrong with the rudder use, and reversal use, and brutality use ? I haven’t a clue! You’d have to ask the Learjet test pilots or whoever decided on that recovery technique.

Stopping the bad divergent oscillation is not all : probably your aircraft wants to play it again ! that divergence had a cause, and watching the motion quantatively helps to fly safe at home avoiding a new divergence with your jammed yaw damper... I agree that in a divergent situation it may, probably will, happen again; but telling the pilot to watch the motion like a hawk to prevent build up of any roll oscillation is surely not the solution? In this regard prevention is better than cure.
Can we agree that a divergent dutch roll is only likely to build up if the aircraft is either naturally unstable in that mode or if the dutch roll is so lightly damped that inappropriate pilot inputs may drive it unstable? In either case the aircraft would be deficient against the certification requirements that call for it to be controllable without the use of exceptional piloting skills. Under modern certification rules (FAR 25.1309) the allowable probability of any system failure is linked to the consequences of that failure. So if yaw damper failure would result in a Hazardous situation, i.e. one :

which would reduce the capability of the aeroplane or the ability of the
crew to cope with adverse operating, conditions to the extent that there would be:
(i) A large reduction in safety margins or functional capabilities;
(ii) Physical distress or excessive workload such that the flight crew cannot be relied upon to perform their
tasks accurately or completely; or
(iii) Serious or fatal injury to a relatively small number of the occupants other than the flight crew.
then the failure probability would have to be Extremely Remote that is to say less probable than once in every 10^7 flight hours.
This being the case, I think that the introduction of quantified criteria for the pilots to monitor is not necessary.

The final object of certification is to do the aircraft safe for the wanted use. Today we have to increase air safety despite crashes statistics are getting better. All the crashes which can be avoided have to get progressively suppressed. Well you won’t find anyone to disagree with those sentiments on this forum! But I have found over the years that if you have a problem it is best to attack the major contributors first. Today the major players in accident statistics by far are LOC and CFIT. The latter is being addressed and the rates are coming down, but I’m not so sure about LOC. There are a lot of things in there where better communication between the engineers and pilots would pay dividends, which is why I read with dismay some of the us vs them comments on these pages.
Even so, you would struggle to find any instance of an accident attributed to a divergent or neutral dutch roll characteristic. [I exclude the subject of this thread because the natural dutch roll was well damped (yaw dampers still operative) and because of the inappropriate control inputs]

Changing certification rules can perhaps help, and if it should help why not try ? Perhaps it could improve the speed of information from engineers to pilots ? Alas! The one thing that has come out clearly in these discussions is the virtually complete exclusion of trained pilots from the certification rules. Until that blockage is removed there is, I fear, little chance that changing the rules would speed the passage of information.

(I know that you will teach me something there as you are a specialist of that beautiful adventure...) Ooops! This is an anonymous forum

misd-agin

10th Oct 2013, 13:20

What's the link for the DC-9 manual with the limitations you mention?

misd-agin

10th Oct 2013, 13:26

flarepilot - regarding Hoot Gibson you said you remember what he said 32 yrs ago on 60 Minutes. CBS put out a report on the accident that took an entire hour. It wasn't 60 Minutes but a special report. Interviewed passengers, crew, etc. Is that the report you recall watching?

DozyWannabe

10th Oct 2013, 17:02

Clandestino, does not Airbus teach pilots with loss of IAS that holding last attitude and power and getting out UAS checklist is the answer or do the French rely on Airbus automation?

Of course if the auto pilot clicks off you need someone that knows how to hold an attitude and not just pull up.

Bubbers, you've answered your own question, because if the Airbus's systems detect a UAS condition, then the automation will automatically disengage. The old UAS procedure is available in the AF447 report, but the gist of it was to maintain a pitch of no more than 5 degrees and use appropriate power settings. I believe it has since been revised to read more simply, but in practice it's much the same.

What has changed for both Boeing and Airbus manuals since AF447 is the approach to training for stall handling - which was considered inadequate across the board as it relied purely on avoidance on approach to stall and had no advice or instruction for recovery when a stall developed (consequently meaning that a significant chunk of airline pilots had not practiced recovery from a stall since their PPL days).

misd-again: I think this is the report you're referring to:
http://www.youtube.com/watch?v=JYHfrk6EVHU

AirRabbit

10th Oct 2013, 18:37

…also had the even greater pleasure of chatting with WEBB, who wrote, "FLY THE WING" and it is an equally fine book. One part of the book opened a new vista in windshear to me and I sought him out through the publisher.

He called me, chatted for 1 hour on the phone, and told me that I GOT IT! (ref : the art of flying) He then sent me some unpublished short stories which were great and a brand new autographed copy of his latest edition, also echoing the phone call sentiments.

I also had the pleasure of being able to call Jim Webb a good and personal friend of mine for quite some time when he was actively training and checking EAL DC-9 pilots in Miami and in Atlanta. He had a unique ability to be able to tell what a pilot was doing and, from that, developing his own way of dealing with any problems or misconceptions his student was displaying. I lost track of him starting around 1980-1981. Later, I did learn that he had retired from EAL but was not able to find him after that. I too have a signed copy of his “Fly the Wing” – and have very fond memories of evenings in the bar on 36th street – across from the EAL Training Facility in Miami.

misd-agin

10th Oct 2013, 19:55

Dozy - that's the report. Interviewed in Costa Rica. No mention of the rudder. Memory, especially 32 yrs after the fact, is tricky.

misd-agin

10th Oct 2013, 19:56

flare - perhaps the DC-9 speeds given are Va at that altitude?

con-pilot

11th Oct 2013, 17:43

Well, okay here we go.

I"ve flown it and offered what I remember from 30 years ago, you haven't flown it and offer what you heard from some guy.

I'll fess up and admit that I am that "some guy". I have flown, for a living not just a single flight, the Sabre 40/60, the Sabre 80 and the Sabre 65. I have have hand flown all of them from takeoff, climb, cruise at FL-450 and approach/landings. Of my 21,000 plus hours of flying time, over 3,000 of those hours are in Sabreliners. My last flight in a Sabre 40 was in 1984, last flight in a Sabre 65 was in 2005.

You are wrong about the aileron limitation of using more than one half aileron deflection above any altitude. The only aileron limitation of the Sabre 40/60/80 is:

From page 1-16 of aircraft limitations in the Flight Safety International Sabre 40/60 pilot training manual, last updated 1982, paragraph H, Maneuvering Limitations;

DO NOT USE MORE THAN ONE-HALF AILERON DEFLECTION ABOVE 225 KNOTS.

This limitation was not, repeat not, due to any structural concerns of the airframe. The FAA added this limitation due to the fear of the FAA that the rapid roll rate of the Sabreliner 40 was too rapid for the average civilian pilot at any airspeed above 225 knots*. The FAA decided that the risk of loss of control could result from a full aileron deflection at any speed above 225 knots, resulting in possible lost of control of the aircraft.

The Sabre 65 has no such restriction.

I will now state for the record; the Sabre 40/60/80/65 are very delightful to being hand flown, regardless of altitude (including FL-450), airspeed and in any configuration.

Only two other aircraft that I have flown that can equal that statement, any and all Falcons and the Lockheed Jetstar (-8 and the 731).

Therefore, in my opinion, a highly experienced opinion, any pilot that struggles to hand fly a Sabre 40, at any altitude or airspeed is either a very poor pilot, a very inexperienced pilot or has never done so.

Your choice to make.

Oh, edited to add.

The US Navy bought a number of Sabre 40s from the open market a few years ago. Then these 40s were flown to Perryville, MO to be completely overhauled and modified to Navy specs. One of the modification was the additions of small vortex generators on the wing in front of the ailerons, to increase the roll rate at full aileron deflection, at any speed under VNE, to increase the already impressive roll rate. These Sabre 40s are now T-39Ds.

* Which means that a FAA test pilot scared himself during the certification flights of the Sabre 40.

Lord Spandex Masher

11th Oct 2013, 18:47

Hold up. The facts stated by Flarepilot were merely the opinion of an inexperienced pilot with a poor memory of what he is actually talking about?

con-pilot

11th Oct 2013, 18:51

When I flew it to FL450 without autopilot I had 10 hours in it and it was my first jet. and it took a little getting use to...but in a few minutes I had "THE HANG OF IT". SO excuse me again.

So your answer is a very inexperienced pilot . Fair enough, would have helped if you had said so at the start.

The Sabre 40 was the third aircraft I was typed in, the Jet Commander and Lear Jet (Lear 24) were the first two. After hand flying the Jet Commander at altitude, it was a pleasure hand flying the Sabre 40. The Lear 24 was not all that bad, but the 40 was much easier, nicer and more comfortable.

so some guy, did you happen to fly for HP?

No, the Sabre 40 and 65 was in corporate flight operations and the Sabre 80s were ex-FAA flight check aircraft that I flew while I was flying for the US Marshal Service.

BUT again it proves my point.

As for your point, I'm unsure of just what point you were attempting to prove. All I am responding to is your statement that flying the Sabre 40 was extremely difficult as compare to other aircraft that you have flown. Which indicated to me that you had experience hand flying other jet aircraft at that altitude. But now I understand that you did not have any previous experience hand flying other aircraft at that altitude, which makes what you posted very understandable.

AirRabbit

11th Oct 2013, 19:18

Quote:
Originally Posted by AirRabbit
To me, this is what I think that F/O was doing ... reacting with a skill set and doing so out of panic ... attempting to function without thinking logically or reasoning to any degree and was, instead, functioning out of an overwhelming feeling of anxiety and frantic agitation.

I'm afraid I agree with this one. Seemingly he firmly believed his actions were appropriate without stopping and checking whether they really were.

Well … when someone is operating out of panic, there is virtually no time where the person would “stop to check” anything. They are also not doing what they’re doing out of a belief that whatever it is would be proper or not. When someone is panicked they do whatever they do out fear and/or supremely heightened anxiety. There is no, or exceptionally little, conscious awareness of what they are doing. Their actions are formed from what some might call “a reservoir” of physical actions, the knowledge of which is buried in that person’s subconscious.

Someone on this forum has mentioned something called the “startle factor” – which has come to be something that psychologists (primarily experimental psychologists) have described as the “blinding” period of time that starts when something happens and continues until the time the participant recognizes that something has happened – and it is usually an extremely short period of time. However, when that participant does consciously recognize that something has happened, as far as I know, there is no standard of performance from that point forward. If the event is recognized, there may (or may not) be an action, or multiple actions, that could be satisfactorily taken to resolve the situation. The question is whether or not those actions would be effective only if taken in the proper sequence, and if so, will that person have the cognitive understanding of that requirement, and be able to logically take those steps, in that order? From here, comes the question of what to do … how to train … so that those who might be at risk for encountering unknown and unexpected events that could have tremendously serious consequences … could be expected to properly and successfully respond to the circumstance that generated the startle.

As someone whose career has been primarily devoted to education and training, I can say that, so far at least, I have seen nothing that equals the repetitive practice of doing something the right way, in the right sequence – over and over and over and over. The only variation that should be included (and it SHOULD be included) is the VARIABILITY of the initiating circumstances where each such variable initiation would result in the person having to respond with the appropriate steps, taken in whatever sequence that will get the situation to the desired level of completion. In aviation, I believe that this would be most logically accomplished by having pilots exposed to having their airplane experience “upset conditions” (including approaches to, and the development of, aerodynamic stalls) through as many variations as would be logically possible. The plan should be to have those pilots follow a logical process to maintain, or regain and then maintain, their airplane in a recognized and desired condition (i.e., position, attitude, altitude, airspeed, and configuration). To me, pilots practice doing this all the time when they are operating through the use of the primary and secondary controls to maintain (or regain and maintain) straight and level, un-accelerated flight. This training should focus on using all the available indications – mostly the flight instruments – ALL of the instruments – as well as the cues provided by sound, visual, and body position in space. And, when the pilot has developed a process that seems to be functional in all of the situations presented - the training should shift to achieving the same results but limiting the references to which the pilot may refer in taking the actions that he/she believes to be appropriate. And, in case you miss my meaning here, I'm talking about limiting the number of instrument references available. Of course, constant and vigilant observation, input, and correction (when necessary) remains a requirement for instructors during this training.

To my knowledge, this is the only way that pilots can be properly prepared - both mentally and physically - for something to occur for which there is no anticipation, and possibly no recognition. And it should be stressed that knowing "why" or "how we got to this position," is not as important as knowing "what to do now."

Brian Abraham

11th Oct 2013, 19:21

Lord Spandax. Time will prove that flarepilot is our dear old SSG, aka teldorserious, who has never sat at the controls of any aircraft. Serial sciolist. Does spin a good yarn I must admit, which sucks people in. His claims are becoming more breathtaking with each new identity. Next we'll hear how he made ace status in the Vietnam war flying an F-4, or perhaps how he walked on the moon.

Congratulations ace on getting a fact partly correct. You've reached a high point in your contributions.

con-pilot

11th Oct 2013, 19:30

and at least I could, from memory, indicate at least one plane that had a limitation on control movement.

Yes, but in the case of the Sabre, except for the 65 which does not have that restriction, it was more about pilot capability rather than a structural issue.

Also, the 65 not having that restriction was the reason I had to look up the limitations. I could not say for sure that the 40 had any control movement restrictions or limitations.

Well that and being an old fart. :p

oh and con pilot...I seem to remember that at FL450 one of us had to be on oxygen all the time (it might be my memory fade or not...what do you remember?)

Actually above FL-400 or FL-410, depending on which pressure controller one had in the 40 and FL-410 for the 80 and 65, all occupants in the aircraft must wear an O2 mask, not just the pilots.

That's what the limitations are. I'm sure every Sabre operator complied with that. ;)

Lord Spandex Masher

11th Oct 2013, 19:54

Brian, I actually think that he's a recently banned poster called sevenstrokeroll. He has the same habit of single sentence paragraphs and starting each one without a capital letter, mostly. Oh, he used to get all shouty about his experience too.

SSR, 31 years ago I wasn't a professional pilot. I am now. I guess that answered your question.

my point was this: any plane with an unusual or unexpected characteristic should have a placard or a statement in the limitation section to warn the pilot

Thing is chap, the rudder doodah isn't a characteristic limited to just an A300 it's relative to ALL transport category aircraft and is, therefore, NOT unusual.

Lord Spandex Masher

11th Oct 2013, 20:23

Something to do with drumming but he used to go on about the same thing as you. And flew the DC9, like you.
http://i1347.photobucket.com/albums/p701/Spandex9/2cdc60fd-f7eb-4ef9-a23e-c6a4e67c7515_zps75e5d546.jpg

Most transports have ailerons and if you use too much you may roll upside down. Yet two transport cat planes have limitations published (maybe more)>

Did you really need a placard to tell you that?

Can't you just admit that the pilot actions were incorrect and were the cause of the rudder separation?

Oh, and why do you think that I'm a novice?!

AirRabbit

11th Oct 2013, 20:32

know what a 4 pt roll is and an 8 point roll, even a 16, but what is a 7 stroke roll?

Well, I was always under the impression that a “7 stroke roll” was a roll completed by a pilot with 7 passengers aboard, where all 7 suffered an incapacitating stroke when they thought they were going to die. The only thing I can’t remember is how many of the 7 actually died from the experience ... or was that a story told by old heads to younger wet-behind-ears novices?

Oh … a quick supplement … I find it curious that anyone would think that a placard, about anything, mounted anywhere on the airplane, would prevent someone from doing anything after that person panicked and responded out of that mentally debilitating state.

Lord Spandex Masher

11th Oct 2013, 20:35

And that the Airbus 300 didn't have such a limitation published.
Does any transport aircraft?

I'm not questioning your credentials just highlighting who you are and the fact that you are like a dog with a bone. I think it's only fair that people know who they're arguing with.

You only answered one of three questions in my previous post.

Does thirty and a half years count as novice SSR?

Lord Spandex Masher

11th Oct 2013, 20:44

No, no, no, no, no! The limitation is to not repeatedly reverse control deflection. Not the amount control movement versus airspeed as you put it.

Which other transport aircraft have that limitation? It's an easy question that even a novice can answer.

bubbers44

11th Oct 2013, 22:40

Lord Spandex Masher

11th Oct 2013, 23:06

Bubbers, the same :mad: place that you've been told before.

SSR,
reversals bad,
You know that despite NOT seeing a placard. So how do you know?

The A300 didn't have what limitation published?

Could you also explain how CRM is in any way relevant.

tubby linton

12th Oct 2013, 00:26

RUDDER TRAVEL LIMITING The rudder travel limiting system modifies control inputs to the servo controls, to vary rudder travel in relation to airspeed (Vc). Limitation is such that the maximum deflection which can be achieved by the rudder remains lower than the deflection which would induce limit loads on the structure, throughout the flight envelope.

The system is composed of: • A variable stop unit consisting of an articulated lever operated by an electro-mechanica]. actuator, end a transducer unit detecting lever position. These items are all mounted on a frame assembly located downstream of the differential between the AP and yaw damper actuators. • Two control and monitoring computers designated FLC (Feel and Limitation Computer). • One RUD TRAVEL control panel, one PITCH FEEL & RUD TRAVEL maintenance panel and five electrical power supply circuit breakers.

The variable stop lever is operated by an electric actuator which consists basically of • Two AC motors, supplied with 26 V ,400 Hz • A single reducting gear actuated by both motors, which are rigidly connected. • A nut/screw system, driven by means of a torque limiter • Mechanical end of travel stops • A torque limiter provided to protect the reduction system from any abrupt jamming of the output shaft, particularly when it reaches the mechanical stop.

The actuator is servo controlled and is monitored through a transducer unit driven by variable stop lever movement. The transducer unit, comprising two inductive transducers is identical to the one used in the spoiler control system.

In the event of a rupture or disconnection of an actuator attachment a retention rod limits actuator movement to prevent it from jamming the variable stop lever. A spring returns the lever to the ‘low speed' position where full control deflection (÷ 30°) is possible.

Feel and limitation computer contains the circuitry required for two functions : Rudder travel limiting and pitch feel.

The FLC is a digital computer comprising two different computation channels: • Rudder travel limiting/pitch feel control channel • Rudder travel limiting/pitch feel monitor channel.

Safety of the systems is ensured by control and monitor channel programs which are intentionally different

Monitoring of digital computations which are performed by control and monitor channels with the same input data, achieved by comparison between the results of both channels, by mean of analog comparators.

bubbers44

12th Oct 2013, 00:33

Lam, no the exact rudder pedal FDR reading, I assume, comes from a mechanical sensor at the pedals but it would be cheaper to do it at the actuator. I know there is rudder pedal and actual rudder movement sensing. Thought some maintenance guy could verify that. Loosen up.

bubbers44

12th Oct 2013, 01:59

LSM, I know I did one letter wrong. I forgot the e. Asking a question because I have no way of finding it from someone who know isn't lame, it is just the only way I know to get an answer. Where is the rudder pedal sensor for FDR source located on an A300.

bubbers44

12th Oct 2013, 02:06

CRM for me was quite simple. I just said fly any way you want and don't bend any rules, fly safely, keep the passengers comfortable and please don't show me something I have never seen before.

HazelNuts39

12th Oct 2013, 08:46

bubbers,

Where is the rudder pedal sensor for FDR source located on an A300.See my post #151. The report talks of rudder control cable stretch. That implies that the rudder pedal sensor is located near the pedals.

A Squared

12th Oct 2013, 08:58

Not to keep going back to the same A300 crash but does anybody know exactly where rudder inputs are measured? Mechanically at the rudders or before the rudder actuator which apparently was the cause of the MIA uncommanded rudder inputs. This has been reported to be a hydraulic valve malfunction to the actuator. Was the rudder pedal input measured before or after the faulty valve?

The sensor for the rudder pedal position is located under the cockpit floor, it is directly attached to a bellcrank aft of the FO's rudder pedals.

The rudder position is measured with a sensor attached to the lower corner of the actual rudder, directly measuring the movement of the rudder relative to the vertical fin.

Look, I understand that for reasons known only to yourself, you're searching for ways to blame this on the airplane and not the pilots. I have to ask, do you imagine that the NTSB, upon finding that there were multiple rapid rudder reversals which caused the vertical stabilizer failure just said: "Hey, let's blame it on the pilots and not investigate any other possible sources of the reversals. That way we can wrap this up and go home early" ?

That seems to be the common thread of all your posts, that the NTSB didn't investigate any other possible causes of the rudder reversals. That the reversals were caused by something else and that the NTSB just blamed it on the pilots because that was what was easy. I'd recommend that you go read the NTSB report, yourself. You'll find that they spent a lot of time on investigating everything that might have caused the ruder reversals. This included inspection of the system components recovered from the crash, analysis of the rudder control system together with the yaw damper and autopilot system, the rudder servo system, and extensive testing of all of the above on identical aircraft. A great deal of that testing was focused the question: "Is it possible that the rudder position and rudder pedal position data which indicates pilot input could have bee caused by something *other* than pilot input" It's not that nobody ever thought to ask the question. They did. And the answer was: "probably not"

As as far as your references to the MIA incident, that was due to an autopilot yaw actuator clutching mechanism which failed to disconnect when the autopilot was selected off. This has already been discussed in this thread previously. That also was investigated by the NTSB in their investigation of AA587. The airplane was being hand flown, the autopilot had not been engaged so a disengagement failure was improbable, the controls had been checked on the ground and there was no interference as was present in the MIA incident, and the Yaw control autopilot servomotor was disassembled and examined and the autopilot yaw input was found to be disengaged.

So, yes, the NTSB *did* consider that this might be related to the MIA incident. Yes, they *did* investigate this possibility, and no, there was nothing which indicated this was the same cause.

Chris Scott

12th Oct 2013, 10:36

Quote from bubbers44:
Not to keep going back to the same A300 crash but...

Quite: as any casual passerby might conclude, this thread is mainly an argument about CRM between two forumites whom no one wants to share a cockpit with, and the handling qualities and placards on Sabreliners - no longer simply a serious discussion of whether rapid, alternating, full-travel rudder applications are warranted, and need(ed) to be considered in the design and certification of large jet transports.

Tubby, HN39 and A Squared,
Thanks for bringing us back to reality; not that facts and logic are likely to silence the peanut gallery...

john_tullamarine

12th Oct 2013, 12:14

Not often my patience runs out.

Several folks have been sidelined. Perhaps, now, we can get back to the discussions at hand ...

A Squared

12th Oct 2013, 12:21

Not often my patience runs out.

Several folks have been sidelined. Perhaps, now, we can get back to the discussions at hand ...

If you had better CRM skills you would have been able to sort that out without banning people :E

john_tullamarine

12th Oct 2013, 12:30

Guess I'm just an old has been failure, then ?

A Squared

12th Oct 2013, 12:36

Just in case it wasn't obvious, that was completely tongue in cheek.

Chris Scott

12th Oct 2013, 15:05

A Squared

12th Oct 2013, 15:13

Quote from A Squared:
If you had better CRM skills...

Hang on a minute! In my experience, it's often those who lack them the most who try and play the CRM card. Must say I didn't think you were in that category.

Quote from A Squared:
Just in case it wasn't obvious, that was completely tongue in cheek.

Oh, really? Having read the last 4 posts one-by-one. this old fart was convinced you were serious...

OK, well it was supposed to be a joke. Take a look at my post. See the :E thingy? To me that means "I'm being a smart-ass pot stirrer, and the fact that it's smiling means that it isn't particularly serious.

What does that emoticon mean to you? Apparently it means something different to you that it does to me.

Chris Scott

12th Oct 2013, 16:37

Quote from A Squared:
OK, well it was supposed to be a joke. Take a look at my post. See the http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/evil.gif thingy?

I get it now. Never did properly understand these new-fangled emoticons. Okay, in view of my advancing presbyopia, I'll turn up the browser magnification in future!

But it's not little me that you need to mend fences with...

A Squared

12th Oct 2013, 16:41

But it's not little me that you need to mend fences with...

If you're referring to John Tullamarine, I'm hoping any misunderstanding has been clarified ... . John?

bubbers44

13th Oct 2013, 00:13

I won't post on this thread any more. I have made my statement and thanks for the info on mechanical rudder info. That is all I WANTED.

john_tullamarine

13th Oct 2013, 09:46

In case anyone is concerned that my delicate and fragile little ego may have been forever destroyed ....

I though it pretty obvious that A Squared's comment was a good natured jibe and responded in kind ....

We Ozzies tend to have thick skins and a laid back view of life ...

AirRabbit

13th Oct 2013, 21:05

“…thick skins and a laid back view of life...”

Of course, I could be wrong … but I always thought that having one, obviated the necessity for having the other. Presuming that’s correct (although, I probably should acknowledge that I have been known to have embraced more than one incorrect presumption in my life) do we apply some kind of variation of the “two-wrongs-don’t-make-a-right” or “a double negative equals a positive” kind of literary reference - meaning that you are vulnerable to all kinds of insults and slanders - or do we take it at face value, implying that you’re “insulated-times-two”? Just wondering… :)

john_tullamarine

13th Oct 2013, 21:20

Quite insulated .. with a shape like mine, what else could I be ?

roulishollandais

13th Oct 2013, 22:46

:ok::D:)John, we all love you.
You are the best moderator, friendly, gentleman, professional, respectuous of expression freedom.:D:ok::)

john_tullamarine

14th Oct 2013, 01:17

..enough, already, lest I get a swelled head without any justification ... now, back to the thread ...

AirRabbit

19th Oct 2013, 21:15

So … it would seem that those here who suspicioned that airplanes should never be “over” controlled – in any axis – or were not sure, but have now seen the results of doing so, are now similarly opinionated … AND … at the same time, it would seem that those who never knew that something like this could ever happen, are still convinced that it was the turbulence from the preceding heavy airplane that caused this tragedy and no herculean effort mounted by any pilot, including any of the first Mercury Astronauts, would have made any difference.

I wonder if any of this second group is interested in proposing a new set of regulations about “following behind” a suspiciously heavy airplane. Perhaps we all could have something like the WWII silhouette books – where each airplane type would be issued a specific silhouette book outlining a suggested following distance behind which we should fly our airplane. Of course each airplane type would be required to carry such a book, and each such book would have all OTHER airplane types, identified by silhouette, and contain the safe following distance to be maintained behind each of the so-identified silhouetted airplanes. The only 3 questions I can think of at this time are: 1) should such books contain a “required” or a “suggested” following distance; 2) would this distance apply regardless of the existing weather conditions; and 3) would each airplane’s radar have to be modified to pick up the ATC identifications to indicate what airplane type is being referenced? Of course, weather conditions could easily be cause for a seemingly endless number of revisions due to maneuvering capability of the following airplane, the capability of the radar, and the alternative weather paths that must be available prior to penetrating said weather conditions. :8

roulishollandais

20th Oct 2013, 00:08

a new set of regulations about “following behind” a suspiciously heavy airplane. Perhaps we all could have something like the WWII silhouette booksThese rules already exist and are used by ATC. Today these "books" are computer files..
ATC had that information in their files over the Queens and was separating the two airliners. It was not the weather but the turning path which put the A300/600 in the wake turbulence of'the B747. It was not the wake turbulence which destroyed the VS but the rudder pedaling. would have all OTHER airplane and what if following the same type? airplane’s radar have to be modified to pick up the ATC identifications to indicate what airplane type is being referenced? flying IFR in FIR without ATC? Or would it be a add to the TCAS? In controlled flight it would be an illogical repartition of work, between ATC and pilots, IMHO. ATC must improve the actual separation distance, included at landing (we started that discussion re Asiana).

I suggest an addendum to the traditional flight enveloppe, of the quantified limitations/enveloppe about position&time, speed-rate or rotation, and accelerations describing the plane dynamic considering the transient parts of piloting (phase planes). Math and computer Science of aerodynamic was not enough developped when they imagined the flight enveloppe.

10Watt

20th Oct 2013, 01:35

Do any of you actually have a professionial pilot licence ?

Or a ppl?

Or lapsed ppl?

Or, of course, skill at playing games ?

Oh dear.

Sorry guys l didn`t mean to cause offence, wrong place for me.

Take care.

AirRabbit

20th Oct 2013, 22:20

roulishollandais –

I guess I was presuming too much … again. Please understand that I am fully aware that ATC had/has all that information, and that they were most surely observing the separation of those two aircraft. I also completely understand that it was NOT the wing-tip vortices that caused the A-300 tail to snap off. What I was attempting to say – however so badly ironic as it appeared – is that it seems that those here who do know, understand and accept the cause, and others here who don’t know, still refuse to believe that a pilot could ever make such a basic mistake, and therefore continue to attempt to present their own experiences that no one here believes for a second, to try to affirm the airplane construction as the true culprit. Every aviator on this site knows that NO pilot is going to go around “kicking the rudders back and forth” … whether they say they do or not. These poor examples of intelligent beings are simply stuck in their belief that it was the airplane that simply fell apart – and I was attempting to show how idiotic it would be to accept that conclusion and then ironically offer possible solutions to what they want us to believe was the accident’s cause. Sorry, if I was a bit too ironic. I’ll try to watch that in the future – but, I make no promises.

10watt -

I think, if you decided to hang around a while longer, you’d find that most of the participants here do indeed have professional credentials … and it just may be that it is probable that you have read the offerings from those few to whom your questions are quite apropos. Unfortunately, that’s the risk one takes for regular participation on an anonymous forum such as this one … however, it wouldn’t take long before you would be able to pick up on those commenters in whom you might be able to find some degree of logic and experience … and correctly identify those who could spend their time more advantageously by blowing their hot air into party balloons.

john_tullamarine

20th Oct 2013, 23:16

... and correctly identify those who could spend their time more advantageously by blowing their hot air into party balloons.

I like it, good sir. .. indeed, quite pertinent on occasion.

roulishollandais

20th Oct 2013, 23:52

@AirRabbit
Thank you for your development.Effectively I did not understand that you were extending humour and irony so long in tech log forum... In France we say "the shortest [jokes] are the best". I thought it concerned only the use of the book. My bad! Continue as you are used to.
This thread seems to be very creative in any sense!

AirRabbit

21st Oct 2013, 03:04

roulishollandais :

Thank you for the very kind response … but, I should be the one pleading “my bad,” and not you. You, sir, very obviously read, write, and understand the English language, and do so quite nicely, when, very likely (at least apparently … due to your stated location) English is probably not your “native language.” I’ve traveled a good deal around our world and I am very conscious of the reputation my countrymen have as “Ugly Americans” – and it makes me realize that all of us “Americans” have a responsibility to offer a more accurate sense of American behavior that is demonstratively different from that all-to-often-used (and sometimes, quite regrettable and quite accurate) description. Americans like me (with me very likely being at the front of the line) should be more aware and considerate of all of our neighbors, all over the globe, who participate on this forum. All of this is to say … I was serious about attempting to watch, and curb when appropriate, my easily surfaced ironic statements … but, unfortunately, I was also serious about not being able to make any promises. That said, you can be sure that any irony I may project is not meant to criticize or belittle – only to demonstrate the underlying conviction I have about the subject being discussed. See you "around the pattern."