Whatever! That is what happened.

Maybe out of control yawing would give you a clue rudder movement is involved. Rudder pedals are not the same as rudder surfaces as you know.

Reminds of Bonanza V tails coming off at Vne...but the speeds were so high as to create a flutter, oscilation. Ofcourse that was a mechanical problem, blamed on pilots going to to fast, but ofcourse everyone has the tail mod now, surprise surprise. So ofcourse, Beech wasn't to blame, but you haven't had a V tail come off since. Surprise surprise.

I think it was the Meridian that had the tail come off in turbulence, everyone said the A/P did a pitch over, exceeded Vne causing the tail to come off. They have an A/P check, reduced Va for turbulance and forced the pilots to go to school to fly this tricky plane and how to handle it. They did a tail mod too...surprise surprise.

So the Airbus tail comes off...did they buttress and mod the tail or didn't they? Why fix something that aint broken?

Rabbit by your own post you mentioned that your NTSB guys show you the real deal but offical findings are different, for reasons you can't fathom. It's called politics and economics.

That's not what I said. The official NTSB reports that I see are the same ones you see. I am acutely aware of the "politics" that happen in governmental agencies ... but the same kind of "issues" are every bit as prevalent in non-governmental organizations - from airlines to churches. Where ever there are policies and procedures, there's the makings of short-cuts, special deals, lack of publication isssues, and all the rest. The offical NTSB report is available to anyone who wants it. All the FDR traces, the CVR transcripts ... everything that is used by the board in its determinations go into their Official Report. It's been a while, but I imagine that the NTSB has a web site from which anyone is likely to be able to download a oopy of any report the board has published, including AA587. What I said was that I have seen information contained in the Official NTSB Report and when I read the text of the Boards findings - there are times that it seems that some of the contents of the report are not addressed in the findings. I've never been able to get anyone to explain how that may happen ... but I know that it does occur. Certainly you can get an understanding of a novel by reading the Cliff Notes version ... but its not the same as reading the book! IF you want to know what the NTSB had in their possession, what they had available to review to develop their determinations - I'd strongly suggest you get a copy of and read the official NTSB Accident/Incident Report.

Here is a link to the Summary of this accident. From this page you will be able to download a full copy of the report ... if you are interested.
Accident Investigations - NTSB - National Transportation Safety Board

Air - Their report will say the pilots shouldn't use too much rudder...but what isn't in the report is that Airbus has quietly inspected, fixed, and stiffened up all the tails.

air rabbit


the transports I fly DO have placards for gear extension speeds and flap speeds. don't yours?

and speeds for failure of rudder limiter to engage and for rudder limiter to disengage are all right there.


methinks you protect airbus too much.


and yes I've flown a transport cat plane that did have a placard for the following: do not use more than half control wheel throw above FL400


all sorts of things happen in real life...we even had a special provision for the flight attendants to NOT wear high heal shoes as they were damaging the floorboards in the cabin.


wake up to reality


a plane crashed, pilot blamed

but enough other pilots have spoken up on this forum and in other places to make everyone wonder.


SHEESH

Guys, guys, Teldiserous is the latest incarnation of SSG and has never sat behind the controls of ANY aircraft. A flight simmer at best, and has proven time after time to have little to no understanding of aircraft ops.

I'm no troll as he claims, if anyone should have doubts I'll happily put those doubts to rest.

Oh we did not do that. Our Engineers did. And they used the very same and old formula you find in Books for 100 Years...
Va = Vs * sqrt(n).
No Rocket Science, not brand related.

Line Ops
 

Wouldn't it be nice - particularly on Tech Log - to see a dispassionate debate on the causes of an accident in which one or more of the main contributors, usually of dubious credentials and having lost the logical part of the argument, didn't resort to the usual accusations of corruption and collusion on the part of the manufacturer/regulator/investigator? I'm not holding my breath. :ugh:

For those who haven't flown big jets yet, and who may be impressed by all the derring-do being pedalled by some contributors here, here's my humble line-pilot experience - for what it's worth.

In the period (1971 - 2001) that I flew six different types of swept-wing big jets for a living on boring, public-transport operations, I never used the rudder except to:
(1) keep the a/c straight on T/O (backed up, if necessary, with into-wind aileron but without "cracking" the roll spoilers);
(2) to help induce a mild sideslip just before the flare when using the wing-down crosswind-landing technique (not on the B707!);
(3) to decrab, as necessary, on a crosswind landing;
(4) to keep the a/c straight during the landing run;
(5) to counter asymmetric thrust following an engine failure.

Note that only (1) and (4) involved rapid reversal of input, and only on the ground at low airspeeds. There were one or two colleagues who would use a bit of rudder to increase the rate of entry into a turn (usually when they were trying to captutre the ILS localiser), but this was frowned upon because it involved sideslip. Except in (2), and a little bit in (5), you do not induce sideslip on a big jet, partly because it is uncomfortable for the passengers and cabin crew. But in any case, it is simply bad flying. We do not need full rudder to pick up a wing in a stall because:
(a) IIRC, certification demands that aileron is usable (and recommended) in the recovery from a simple stall;
(b) we do not stall the aeroplane in public transport ops. However, in the extreme case, a stall normally occurs at a low airspeed.

Can I repeat another point I tried to make in a previous post? The A300-600 flight controls and tail-assembly structure are similar to the A310 I flew in the 1980s, although the VS dimensions may be slightly different.
Despite what flarepath would lead us to believe, there is a rudder travel limiter which becomes effective above a certain IAS (a bit above minimum-clean speed, IIRC). That limiter is a fuction of two computers called FACs. If it fails, the ECAM system (which was pioneered on the A310), announces something like "F/CTL: Rudder travel Limit INOP. Use rudder with care above xxx kt." This is accompanied by a master-caution W/L and a SC (single chime). Very similar to the A320 and its successors.

What the above-mentioned contributors are also in denial about is that, despite being reminded by tdracer and others, Boeing has quite clearly recognised the need to warn pilots not to cycle the rudder from stop to stop on its own airplanes. But who ever did?

Owain, I'm wondering if the B52 may have ailerons and elevators that use balance panels like the B707? In which case loss of hydraulics with the rudder, which may have an hydraulic booster like the B707, would not affect them. The main point about that a/c was that, as Armchairflyer says and you would know far better than I do, there was enough of the fin left to provide some degree of directional stability (unlike that B747 in Japan, caused by a botched repair to the rear pressure bulkhead).

Chris,

I really don't know much about the details of B52 design. I am going from this extract taken from the B52 history site:

That suggests to me that they may have retained roll and pitch controls - I note that there is no mention of a power pack supplying hydraulics to the rudder, but as I said, I am looking for confirmation. This in contradistinction to the A300 which would definitely have been without any form of control.

As to flight without a rudder, I think the vestigial fin left on that B52 would not have added much directional stability. OTOH, the B52 had a lot more fuselage aft of the wing root than ahead of it. My experience (strictly ground based!) would suggest that aircraft with highly swept wings can be flown without a fin, although they might wallow quite a bit ("interesting" dutch roll characteristics!) and one wouldn't want to attempt anything more than very gentle turns. Engine failures would be a definite no-no.

Bottom line is that the B52 survived, so it must be possible in at least one case.

NTSB investigation reference or it didn't.

Probable cause: no official requirement to include paranoid delusions into NTSB reports. Write to your congressman if you are unhappy about that.

Quote from Owain Glyndwr:
As to flight without a rudder, I think the vestigial fin left on that B52 would not have added much directional stability. OTOH, the B52 had a lot more fuselage aft of the wing root than ahead of it. My experience (strictly ground based!) would suggest that aircraft with highly swept wings can be flown without a fin, although they might wallow quite a bit ("interesting" dutch roll characteristics!) and one wouldn't want to attempt anything more than very gentle turns. Engine failures would be a definite no-no.

Point taken. Very different fuselage profile from the B747...

That was prior to the B52G models which did away with the bleed air feed services. A lot if leaks that sent hit air thru all kinds of places it didn't belong. That said, the "finless" BUFF was an early model.

It's not about brand B being tougher than brand A and never was. While the 747SP deserves kudos for hanging together in that China Airlines incident, you're talking about a completely different scenario causing completely different load factors on the airframe.

That incident involved a spiral dive - to cut a long description short, the torsional/bending loads are spread across the airframe and occur primarily to structures with spars, such as the wings and horizontal stab. The vertical stab will take some heavy punishment, but the loads only occur in one direction. Reversed sideslips of the kind that brought down AA587 apply almost all the torsion loads to the vertical stab - which is dangerous enough, but when you add in the reversals it quickly becomes more than any design of that size and that nature can handle.

As the photo earlier in the thread shows, not even the 747 has a spar or structural member going from the fuselage to the vertical stab. Like the A300 and pretty much every other aircraft of the type, the vertical stab is simply bolted on through lugs.

Brian - thanks for the clarification on the identity of our FUD merchant.

Utter rubbish. Inspected and fixed those that needed fixing yes, but there was no programme to "quietly" make changes to all of them because it simply wasn't necessary.

@Chris Scott - Amen!

Chris, regarding:
Reading some of the vitriol that passes for "discussion", one wonders what airlines spent all that time and money on CRM for and why, that is, if indeed those contributing are actually transport pilots.
I second your comments which are very well stated, (specifically, points 1 - 5, & a-b), regarding rudder use. Your comments characterize and reflect my own experience in handling transport aircraft.

It’s a shame that you read incorrectly when you interpret my comments here as being a “fan” or a “protector” of Airbus. I’m not particularly “for” or “against,” that particular manufacturer, despite your acusations.

I am quite sure you have not read many, if any, of my previous posts here, and have not had the opportunity to accurately interpret any of what I might offer here. So … let me assure you that I don’t like laying the blame for an accident at the feet of any pilot – unless that is the correct place. In fact, with regard to this specific accident, I seem to recall my previous posts (some 6-8 years ago, or more) saying that the F/O most assuredly was at the controls when this particular accident occurred. It was this F/O who made the control inputs that resulted in the tail separating from the airplane – it wasn’t because of poor workmanship or substandard materials or construction. BUT, after having said all that, I also said that this F/O most assuredly had lots of help in getting to the accident site. I also said that this particular flight encountered 2 wingtip vortices, not just 1. This F/O transitioned the first encounter quite professionally and with very little use of the rudder, if any at all. My question originally (and it remains a question in my mind today) had to do with why the precise, subdued, professional, and very successful transition with the 1st encounter … and the result of the 2nd vortex encounter being the overly severe control applications in all three axes, but most significantly in lateral and directional control responses – and the fact that those responses went to the control limit a good share of the time and consisted of substantially, and very quickly, reversing those inputs. Did he remember his training the 1st time (which was successful) and forget it the 2nd time (which was unsuccessful)? Or, did he forget his training the 1st time, and after recognizing that what he did was successful - i.e., the airplane maintained the desired flight path – then with the 2nd encounter, decided to do something way beyond what he had just witnessed and experienced as being successful and decided to maximize his control inputs? We may never know. But I think it appropriate for all of us to carefully analyze what happened, including what the results were with both of the "corrective actions" taken … and ensure that this information is widely disseminated and incorporated into all airline pilot training programs.

Did the AAMT course once offered by AA have anything to do with the magnitude of response used in this second encounter? I don’t know. And I don’t think anyone can say for sure. I know that the AAMT course did discuss the use of the rudder – but as I recall my exposure to that particular course (and no, I wasn’t employed by AA), was that the use of the rudder would be appropriate to assist in bringing the nose back to the horizon if using down-elevator was inappropriate or ineffectual after reaching an unacceptably high pitch attitude. Once achieving an angle of bank, pressuring the bottom rudder would bring the nose back to the desired attitude with respect to the horizon. I am also aware that AA did modify the content of this course to be sure that they weren’t encouraging an inordinate use of the rudder – and, I understand, eventually dropped the course altogether. However, if this course did contribute to the accident, it would leave open the question as to why the substantial use of rudder seen prior to the separation of the vertical tail did not occur during the first wingtip vortex encounter?

I hope this clarifies my comments for you.

Wouldn't it be nice - particularly on Tech Log - to see a dispassionate debate on the causes of an accident...

Sometimes we mod folks tear our hair out trying to tread that fine line between too much interference (stifling debate to the point of overt censorship) and seeing some folk get too excited (too far beyond the reasonable bounds of polite discussion).

The only alternative to getting the balance wrong on most occasions .. is going fishing, I guess. Consequence of being a fallible human.

@AirRabbit

I doff my cap to you for a thoughtful, well-reasoned and insightful post.

One thing I remember from the time was a BBC Horizon documentary that stated a significant number of that FO's colleagues on AA's A300 fleet had transferred to Boeing types because they believed whole-heartedly in the "weak tail" scenario. Such actions speak to camaraderie and loyalty and they are no doubt noble, even if the evidence points elsewhere.

But if we are to be rational about things then we must follow the evidence, even if we don't like where it may lead. Heaven knows I've been accused enough times of "defending" or "protecting" Airbus when sticking to the evidence is all I've been doing. At the end of the day, even with the speculation over why the FO may have handled the rudder the way he appeared to, there is no arguing with the fact that the vertical stab did not fail until the forces on it exceeded the load limit by a factor of 2.2 times, exceeding the Ultimate load reserve by a factor of 1.47 times.

I, along with a lot of other pilots on this thread, believe overiding an autopilot or autothrottle not doing what you want it to do is improper and should never be done on an Airbus because of Airbus policy.

I guess that is why I always flew Boeings because they were just an airplane and you could overide anything you chose to overide. I know I can correct a situation hand flying but Airbus says, NO, push this button. I think Airbus has made their pilots into flying robots. AF447 demonstrated this when all they needed was one pilot who knew how to hand fly but he was taking his break. Maybe he should have stayed in the cockpit to take care of the children of the magenta line. Pilots should always be pilots and not let the company make you into a computer operator.

Hey John – this forum, and by extension, YOU, do(es), and have done, what most here would describe as a magnificent job of reviewing the posts and allowing the development of what develops. It is a very, very rare circumstance to have what develops here, be even remotely described as an out-of-hand spool-up to name calling and disrespect. All of us here should be so fortunate or work so hard as to find ourselves/themselves an equally “fallible human.” You, sir, and this forum, deserve at least a handful of “atta-boys” for the kinds of information exchange you provide to all of us – and there’s probably no way to measure the value that has produced.

Bubs, are you sure you're replying to the right thread? If you're sure, then JammedStab followed his original post on "Manually overriding autothrust" stating he'd misunderstood the document.

Said document is here: http://www.airbus.com/fileadmin/medi..._SOP_SEQ02.pdf

and the relevant section is at the bottom of page 7.

If you read it in context, all it says is that a pilot should not try to override AP or A/THR by manipulating the controls without first explicitly using the disconnect button.

Note that it also says (emphasis mine):
Yup, you read it right - an official Airbus document telling pilots to handfly. Now, if people paid attention to what Airbus *actually* say rather than assuming the ol' rumour mill must be correct, then that shouldn't be much of a surprise. Unfortunately...

" You, sir, and this forum, deserve at least a handful of “atta-boys” for the kinds of information exchange you provide to all of us – and there’s probably no way to measure the value that has produced."

yessir, very well said, AR, +1

You have, as I think I’ve said before (probably several times), both my respect and my admiration. So, thanks for your comments – and I look forward to reading what you have to say on almost anything, because I’ve long ago recognized that most of the participants here are really after the truth about whatever it is being discussed. It’s far easier to jump on the most popular bandwagon – and sometimes having done so … remain ignorant of the facts … or worse, maybe influence some reasonably inexperienced aviator out there who gloms onto something posted by a seasoned old fart and finds out that he or she has made a serious error in judgment. There is absolutely no reason to NOT learn the truth about anything discussed here – because the truth will not only set you free, it might also save your butt!!

Quote:
Hey John – this forum, and by extension, YOU, do(es), and have done, what most here would describe as a magnificent job of reviewing the posts and allowing the development of what develops.
...You, sir, and this forum, deserve at least a handful of “atta-boys” for the kinds of information exchange you provide to all of us – and there’s probably no way to measure the value that has produced.

Hear, hear... Thanks for articulating those sentiments much better than I for one could have done, AirRabbit. Something as close to the truth as fallible humans can aspire to will out... eventually.

Perfectly put.

And on a more personal note, I should thank the mods for being lenient to an enthusiast with scant qualifications, who as a result has learned more than he ever could hope to have done any other way. Not to mention making the acquaintance of several stellar pilots, engineers and people in the process.

Guys .. enough, already ... lest I get an undeserved swelled head.

However, this forum is too important for the folks who use it to let it swing too far either way .. better we maintain a reasonably polite but vigorous and spirited debating platform for whatever topics arise.

We all have the potential to learn from PPRuNe.

I have a small insight into the IDs of some of the posters. If you or I were to seek their advice on a commercial consultancy basis (and many of them are highly regarded Industry Consultants), we would be paying a small fortune for what we are getting here as freebies.

That never ceases to amaze me.

Really? Airbus stiffened all the tails? On just the A300's? Or the A300-600R's? Is there a difference between the two aircraft? Does it matter?

Or did Airbus stiffen every Airbus tail ever built?
When did they do this? What was the 'fix'?

Hear, hear for and to those who quite rightly have applauded JT. A gentleman much experienced aviation wise, and does the greatest of jobs riding herd on this community of cats. Helo guy myself, know nought of big iron, but through these august pages have had the privalege of correspondance with proffesionals who have worked and flown on aircraft mere mortals can only dream about. All spilling errors tablet induced.

The NTSB Accident Report on AA 587, paragraph 1.18.10 Airbus Technical Note, states:
The Airbus note is not discussed in the NTSB report that was published in october 2004, and I could not find it on the NTSB website. Has anyone more information?

Despite reading PPRuNe and our august posters, I am still ignorant of the exact text of FAA's Va old and new definitions:O Is it Defence secrecy? :p

@Clandestino
• Not sure you have taught new pilots. Did you ?
• We don't have the same definition of "critical [situation]" :mad:

Quote from dutchroll:
Despite reading PPRuNe and our august posters, I am still ignorant of the exact text of FAA's Va old and new definitions.

You and me both!

@Chris, Roulis

I think you will find what you are looking for in posts #21 and 23 of the "Va Maneuvring" thread.

This involves subtle distinctions between "Maneuvring speed" and "Design Maneuvring speed". I suspect this was the origin of this thread, but Teldorserious hasn't confirmed that despite repeated requests.

Va is defined in FAR 25.335, last changed with Amdt. 25-91 Eff. 7/29/97. The change was made to harmonize FAR and JAR.

Agreed HN, but that refers to the design manoeuvre speed. The FAA changes made following the NTSB AA587 recommendation related to FAR 25.1507 and 25.1583

Umm … forgive me, but I’m not sure if you’re asking a question or not … and if you are, I’m not sure what that question might be. If you are seeking to read the FAA’s current definition of Va, here is a reference for you to read: § 25.335 Design airspeeds.

While you're absolutely correct in a technical sense, if I understand it correctly the sequence of events following vertical stab separation progressed so quickly that there wouldn't have been enough time for the hydraulic fluid to drain.

I'm pretty sure that because the aircraft was already in a sideslip, the resultant loss of opposing force from the rudder/stabiliser would have caused what amounted to an unrecoverable flat spin within a fraction of a second, would it not?

@AirRabbit

If you go back to the OP you will find it querying I take this to mean the changes FAA made to their regulations as a result of NTSB pointing out the confusion that existed between Va used as a design speed and Va used as a manoeuvre speed.

If you check out the posts I cited earlier you will find that the FAA made changes to the definition of the latter, not to Va used as a design speed. Consequently I think that referring RH and CS to the latest definition of manoeuvre design speed won't help them - hence my reference to an earlier PPRuNe discussion.

@ Dozy

Not so much time to drain the systems Dozy, just that if the pipes are open to the atmosphere the working pressure drops to zero, so the remaining control surfaces will flop all over the place under whatever aerodynamic hinge moments they might experience.

I don't think we know anything about the subsequent gyrations and I would certainly not like to attempt any prediction - they were nowhere near stall when if happened so I don't see why it should develop an almost instantaneous flat spin - in fact a aircraft that size will not do anything much in a fraction of a second.

Owain,

Thanks, I just couldn't find the thread you referred to.

Fair enough - I was speculating on possible momentum build-up from those pendulum-like yaw movements, but admittedly I'm way out of my depth - so if you say it's unlikely then I'm with you! :}