Dozy, FWIW ... from an older thread ... PPRuNerNorman Stanley Fletcher When there is a corporate disincentive to hand flying, and even punishment, Norman's appeal may become increasingly difficult for anyone to hear, particularly those who are not pilots, who need to hear it loudest.

It always takes two for a disagreement. The fire keeps burning by the aditional coals those two groups are shoveling in. It´s like feeding trolls, wherby i´m not saying that those posters are trolls, but there are parallels.

Honestly i´m tired with this A v. B talk (and i think others too) and it is hindering reasonable discussions. I think you have higher qualities and can contribute more for future safety when letting A v. B. and stone age v. future at rest. If it gets that bad at you that you mix up the pilot (a human being) with the human interface (technical system asociated with the necessary training), then it is time to disregard those posts.

No harm intended.

Franzl;

Jim Reason's Swiss Cheese model, extremely useful, has provided a good insight into human factors but is being challenged in the way any theory is challenged - through increased research and new knowledge, some of it made possible by a powerful computing capability which did not exist at the time the model was introduced.

Alongside (and not in place of!), Reason's notions are those of some superbly-insightful writers such as Sidney Dekker, John Stoop, Charles Perrow, Nancy Leveson, certainly PBL (Why-Because Analysis), who has contributed here in the past and others who are taking "systems theoretical" approaches (to describe it broadly...they may disagree!). Each are worth the trouble in looking up and reading, just as Reason is, for an understanding of this approach. Such an approach is (again!), entirely blame-free; - rather, it attempts to find things out.

Let us examine two notions. This isn't unique and is said in my own words. Others will have expressed these notions differently.

One way to think of an accident is a series of elements or things, which then interact (or don't interact). The focus is upon "things" as (philosophically) solid items with a fixed nature, which then interact with other "things" with their fixed natures which are then portrayed as "causes", which have "outcomes". It is perhaps a mirror of the way the western world approaches most things...in a Cartesian manner, or a mental model that looks at the world as "mechanically linked" in terms of cause and effect, (note the singular form of these words!).

Because human factors deals naturally with the way humans see their world, another way to examine an accident sequence (and view the world!), is in terms of relationships...that which occurs "in-between" things. It no longer sees "things-in-isolation" but instead sees primarily relationships...what goes on in-between things and how relationships change those things. So, an organizational system, which can be printed out as the usual "org-chart" isn't a "thing", it is a living organism which materially affects the behaviour of people within such a system. Therefore, the notions of "cause" and "effect" are significantly changed. So much so, that analyzing a series of events from a "Cartesian" view, (as one might do a physics experiment), cannot work and a better model is needed. Charles Perrow first broached this notion in 1984 in a ground-breaking book entitled, "Normal Accidents". Perrow is emminently worth reading and listening to.

Diane Vaughan (sociologist), wrote about the Challenger accident in a way that analyzes the organizational structure of NASA - the relationships between engineers and managers - there was very little analysis of "things" in Vaughan's work.

Many of us here understand this stuff intuitively but many others do not, and are perhaps a bit stuck in a Cartesian world view in which the notions of local cause/effect = blame are legitimately/automatically attached to any understanding of what happened in the accident and why. Concepts like blame and accountability are legal terms and the legal discourse is quite different than the discourse of the safety process, which is being discussed by Safety Concerns.

This applies to AF447 in ways that have already been very well described and written about here by those who know this aspect of flight safety work. The importance of the sociologists' work in this cannot be over-emphasized, but nor can the engineers' work be set aside. The two need to work closely and this is where the field is tending - a systems theoretical approach.

In the July - September 2011 issue of ISASI Forum has an excellent article on this approach - it is the paper presented by Sidney Dekker and John Stoop at the 2010 ISASI conference entitled, "Limitations of 'Swiss Cheese' Models and the Need for a Systems Approach". I tried the link to that issue of the magazine and it doesn't work yet, but it does work for the entire Seminar Proceedings Vol 14, and you can find their presentation there.

I believe we will learn far more about AF447 using this approach and indeed this has already been put into practise in many of the posts here, but there is always more learning! The benefit of such robust process is it provides a solid basis upon which pet theories and recurring themes may be judged in terms of relevance and consistency as well as their contributory value towards understanding, and where indicated, safely set aside.

- actually THAT is a fundamental mis-understanding of my post. Try substituting the players in 447 into the story. The parallel? The 'surprised' human factor (or 'interface' as some see it. Gulp) - how can aviation safety progress with that frame of mind?

New sheets, nurse! When is the next BEA report if there is to be one?

PJ2
 

Thank you very much for sharing,
i will have weeks to read and study!

BOAC
 

Final report publication is planned by BEA in first half of 2012.

So, we've got many more months to quarrel on A vs B, pilots vs engineers, conspiracy theorists vs rational guys, blame vs safety...:ugh:

@LW_50 (and again, you make me break my personal limits on daily post count - curse you! ;) )

I followed that thread closely at the time, and in essence I agree whole-heartedly with what NSF said, with the proviso that I would have included the A300, A310, MD-11, B747-400, B757 and B767 (and to some extent, the B737 Classic and NG) in that list. Something that has rarely been clearly delineated is the distinction between FBW technology (which applies to the aircraft he lists, along with Concorde, albeit using analogue technology in that case), and FMS technology (which applies to that list as well as any Western airliner that came off the drawing board post-1972). My contention is that the former does not necessarily impact negatively on currency in hand-flying expertise, while the argument that dependence on the latter makes it possible to do do definitely has merit.

If you look at how some people respond to my posts, as opposed to what I've actually been saying, you would think that I must be some kind of blinkered supporter of automation ueber alles, which I categorically am not - and have gone out of my way to make that clear several times. While I agree with some of what people like SC and JD-EE say in terms of the reality of the systems (and respect their expertise), I do not share their confidence in the ability of these systems to operate successfully and safely without the need for human intervention, particularly when the situation begins to degrade from normal to FUBAR.

So all I can do is reiterate the gist of some of my most recent posts - you have two clear cases of recent accidents where a lack of proper training and a lack of understanding as to just how important it is that pilots be fit for duty have clearly contributed significantly. You've got Airbus (of all manufacturers!) expressing concern that manual handling skills have been allowed to deteriorate and that action must be taken to resolve this. There will probably not be another opportunity to take the fight to airline management across the industry for a very long time, so please understand that I am four-square behind any effort on the part of pilot unions and associations to do so. I get weary of all the old Airbus canards being brought up over this accident because it is a distraction from the real problem - a new breed of airline management and executives that don't know anything about the sharp end of the industry that they are supposed to be managing, nor do they understand why the cost-cutting measures that they were taught and are routinely applied in other industries are simply inappropriate for airline operation.

@BOAC - I was referring to the misunderstanding on the part of the driver who expected ABS to save his bodywork and spare his blushes - clearly he believed that ABS was a "magic" braking system that would contravene the laws of physics and make everything alright. Right now, we don't know why the AF447 crew (and the PF in particular) did what they did, whether it was overconfidence in the system through lack of understanding and/or training, whether it was a sustained panic reaction which would have led to the same result in any other airliner, or whether it was a simple case of pulling back on the stick while attempting roll corrections without realising it - to name but three possibilities. It is likely that we will never be 100% sure, so we must work with the information that we do have.

PJ2,
Thanks for the link.
Too late in the evening to read it fully now and make full sense of it.... it's on the to-do list for tomorrow.

I don't blame AB for the lack of piloting skill which 447s' crew exhibited.

It could have easily happened in another type.

The fault was the pilots', plain and simple. They let the a/c get away from them while effectively flying 'partial panel'.

If they had been better trained, or even spent more hours actually flying (by hand) their aircraft then this accident could easily have been avoided.

Probably ( although the wx may have been a factor) all they had to do was leave things as they were and hang on until their airspeed problem went away- as it was bound to.

Straight and level was beyond them. So used were they to the automatics that the concept of actually flying the aircraft was too much.

Autos- and the way they degrade those hard earned flying skills- are the new killer.

Make that "misuse of/overreliance on" autos and you've got my unequivocal support. The autos themselves care not how they are used. :)

@exeng (below) - Actually, I seem to recall reading on the EgyptAir 990 accident that if the yokes on the 767 are pulled and pushed opposite each other that the design caused one elevator to deflect up and the other to deflect down (which I think was later changed). Ultimately the Airbus FBW design depends on co-ordinated flight deck roles to a greater degree, but I don't think it's demonstrably less safe. One can argue that if the PNF had the courage of his convictions he should have held down the priority button and stated "I have control" in no uncertain terms, which would be a variation on the procedure practiced in Airbus training, which makes the reasonable assumption that the pilot relieved of control should relinquish their sidestick. The overriding impression I get from the AF447 interim reports is that the lack of clearly-delineated flight deck roles, for which the ultimate responsibility lies with the Captain, led to confusion as to which F/O should be doing what and may have contributed to the PNF's uncertainty as to whether he had the right to relieve the PF of control.

I agree with Barbies
 

An awful situation to find oneself in, but nevertheless basic attitude + power should have seen them through the airspeed issue.

The stall warning should have alerted the PF to the situation. Even in low level stall training ( I understand the PF had this) then a reduction in pitch should have been almost automatic I would have thought.

Where I have sympathy for the Pilots is in the extreme angles of attack following the stall when the stall warning disappears - and yet when nose down inputs are made the stall warning re-appears. I know others have made the point but I felt it worth re-stating.

The pitch angles on the ADI are abnormal for the stage of flight (i.e. cruise + stall) but not abnormal for take-off and initial climb. 'So what' some may say - but the PF may have thought that such a pitch angle was not so out of the ordinary. (importance of training aginn)

Interesting to note that the PNF took control quite late in the proceedings (probably too late to effect a recovery) and I believe he made a nose down input. I also understand that the PF almost immediately took control agian (or overode the NPF's input) with a nose up input.

Whilst I don't want to start an A/B versus Boeing scrap again I feel that the sidestick logic is flawed in this respect amongst others. On a Boeing it obvious which way the elevator is moving (and in some cases therefore the THS) and on the A/B it is not obvious. I've flown both by the way (including the 320 and the 777 but not the A330).

Both types of aircraft are well designed - some have advantages or deficiencies when compared against each other.

The clue is in training - and what we have in this terrible accident is a crew that has been poorly prepared for the situation they find themselves in. Complex aircraft need rigorous training - but the airlines won't pay for it - and A/B don't recommend it's necessity.

I hope that some changes in attitude from the various CAA's will follow the final report - I won't hold my breath.

Procedure that required setting 5°/CLB by heart was in force at the time of the accident. Page 59 of interim 3 report in English refers.

I see there's fear that it's unsafe and leads to zoom climbs ending in stalls.

It is not and it does not.

You will climb out of cruise condition but if your significant cockpit other fumbles with QRH for a half an hour, you will simply and gently level off at altitude where power required meets power available at 5° AoA. There's no aeroplane that can not sustain 5° AoA below Macrit, from Sopwith Camel, to Belanca Airbus, to CitationJet, to B747, to whatever and with thrust to weight ratios and of modern passenger jets, you will be far fom Macrit at 5° AoA. Do you understand that, for all practical purposes*, your AoA is difference between pitch and flightpath and in level flight AoA=pitch?

Does anyone have anything to add to this except his feelings and suspicions? Like arguments?

Granted, there's no need to go climbing but procedure is not about maintaining altitude. Speedwise, it gives you safe pitch and power for any weight, until actual settings are taken from the table. 5/CLB is just temporary measure and IMHO can be skipped if one knows his cruise power settings and attitudes for different weights by heart or if he was in stable cruise condition and just maintains last pitch and power. However, this would be overriding the prescribed emergency procedure and one must be better sure he knows what he is exactly doing.


*disregarding wing incidence and vertical air currents

Clandestino, a couple of threads back, HazelNuts39 posted a chart that compared stall AoA to mach and altitude, and it appears that you either get stall warning, or stall ( can't recall which thread to look in) at about 4. (Big diff, obviously,, between warning and stall). Something disturbs me about your choosing to champion "rote rote and more rote" as a solution.

What is the point in climbing an aircraft to trouble shoot a problem when you have fewer parameters to mess with by trouble shooting it while straight and level?

Why add a needless performance parameter when trouble shooting a malfunction?

I am at a loss.

Look at what happens with the advocacy of "keep it at five degrees until infinity." (Or the bloody PNF finally gets the QRH out and opened to the correct page).

Pitch up to 5 deg, and leave it there.

OK, while trouble shooting UAS, you get a stall warning. (See above, if I can find that table, I'll repost it).

Now what?

Well, lower the damned nose, you just got a stall warning.

OK, warning goes away, but where should you now assign the nose? What pitch angle.

Doesn't it bother you that you got a stall warning for no good reason by keeping the nose up in a pitch climb for no good reason?

Result is that you just gave yourself a multiple malfunction, so rather than dealing with one, you are now dealing with two.

Ever heard of anyone doing that?

(The "you" here isn't Clandestino, it's a generic "you" pilot in the audience going through this drill).

Jcjeant,
You brought it up about the inadequate search. Sometime in the last year, it was published that the french nuclear submarine was listening for the ping of the black boxes incorrectly with their sonar. The ping of the black boxes is at 37.5 khz, which, of course, is beyond the range of human hearing. A 5th grade science student would have known that! Just wanted to give an example of how pathetic the search effort was.
A great deal of money was spent to just go through the motions (sending a "nuclear" sub sounds impressive). It was not in France's best interest for the black boxes to be found sooner rather than later. The people were already dead, and Air France lawyers, Airbus lawyers, and the BEA were all on the same page. I remember a bunch of Airbus military tankers were about to be sold. Sure, everyone wanted to know what happened to AF447, but not just yet, and a couple of years for emotions to cool could help minimize lawsuit payouts as well.
Hate to be such a cynic, but it's life in the real world.
Thankfully, the BEA, Airbus, and Air France may not be on the same page any longer, and the industry can learn from this tradegy.

@Coagie:

In 1988, the USS Vincennes incorrectly identified an Iran Air A300 as an Iranian Air Force F-14 and shot it down. In 1985, the joint US/French Titanic expedition incorrectly identified an immediately strong sonar reading at the beginning of their search pattern as an equipment malfunction and spent weeks headed in the opposite direction of the wreck, and it was only when - in a last-ditch effort - they threw all the video imaging equipment at the area a short distance from their point of origin that the wreck was actually found.

All I intend to illustrate with this is that neither military operations nor deep-ocean exploration are immune from mistakes, and before throwing accusations of conspiracy around, Hanlon's Razor should apply:

Or even miscommunication and bad luck.

Coagie, what I read was that Emeraude's sonar wasn't initially optimized for 37.5 KHZ, not that it was completely deaf at that frequency. Just because you can hear the pinging in a WWII movie it doesn't necessarily follow that modern sonar is limited to the range of human hearing.

Clandestino;
Let's start from a different point, as something of a counterexample.

Let's say the A330's cruise pitch attitude is a nominal 5deg and a UAS event occurs and the crew executes the memorized items. I think then, you and those here who disagree with the views that I have expressed concerning this procedure would find agreement, as nothing would occur - the airplane would remain essentially level, (given the vagaries of turbulent flight).

So why isn't there broad agreement on keeping level flight? What is the actual Airbus justification for pitching the aircraft up to 5deg? I've heard the justifications but I haven't seen the sources. I have provided sources for everything stated in favour of the argument that the drill is confusing at best and incorrect or executed incorrectly, at worst.

Your comment in your post to which I originally responded does make the point that these drills are created by test pilots and disagreement with same is not something to take lightly. As a general rule I think that is a good principle - who are we to argue - generally?

But as you know very well from CRM principles, in this business if one is uncomfortable with something, regardless of who said it, who did it, or who wrote it, one speaks up and sorts it out and if one is wrong, so be it, no harm done. The airplane only respects the laws of physics. This accident is ample demonstration of that fact.

Given the example at the beginning of this post, I think it can be said that the issue isn't the pitch, (and I think you know this) - the issue for me is the destabilization factor. The point I am focussing upon isn't the idea of not being able to control all this and sort the climb and the recovery to stabilized flight. By pitching up, one adds to one's problems exponentially while one is trying to sort the problem instead of having a stable platform from which to execute the remainder of the checklist.

It simply makes no sense to alter anything because, given everything else equal nothing has occurred to the airplane which requires an immediate "correction". I commented years ago that I cannot imagine any pilot actually doing this and nothing I've read, seen or heard has altered this view because there is no good reason to do this in a transport aircraft - it simply leaves one in no-man's land.

One doesn't even have to know what one's airspeed and thrust setting were before the loss of speed indications...one just keeps the same attitude and when happy, just pulls the thrust levers out of the CLB detent and back to the thrust setting that was being indicated while the thrust was in the THR LOCK mode.

There are no examples that we can reference in the 30+ UAS events listed in BEA Report 1, in which the crew pulled the aircraft up in response to a loss of all airspeed indications.

As I have worked on this I have come around to understanding what the drill and the FCTM says and by all indications, the memorized items apply first, then the level-off, (which I think is crazy and wrong, but I nevertheless wish to argue against it on its lack of merit), but I have posted the relevant sections which govern how this drill is to be done (as stated in two airlines' FCTMs, probably not all airlines and probably not from Airbus...CONF iture responded very early in this discussion with this point, and it will be of interest to learn how AF taught this drill and what guidance is offered in the AF FCTM on the point).

The relevant sections from the two FCTMs I posted indicate that while the memorized items are to be done "immediately", the airplane is to be returned to stabilized flight as quickly as possible and troubleshooting begun before a speed limit is exceeded. Now...I am wondering why a drill should put an airplane in such a situation? Doesn't this have the potential for creating a bigger problem than it is designed to solve?

Hope this is takes the discussion forward, and thank you for commenting.

For Clandestino and PJ2: some bits of old ground that may enhance current discussion.

Some posts Hazelnuts and a few others made germane to handling and stalling at cruise altitude.

http://www.pprune.org/tech-log/45283...ml#post6479432

http://www.pprune.org/tech-log/45283...ml#post6480513

http://www.pprune.org/tech-log/45283...ml#post6481326 (This is a table of AoA and time in the event)

(A comment on control response and time to unstalled a stall jet. )

HN39:
http://www.pprune.org/tech-log/45283...ml#post6485709
Mieklour
http://www.pprune.org/tech-log/45283...ml#post6486989
It certainly was investigated! Aug 1995 and resulted in the fitting of pitot heads with increased heating and a software change to increase the time line before ALT2 was latched. A/P and ATHR initially lost but were restored once out of icing conditions however the lateral twitchy aileron response was very evident for the landing.
http://www.pprune.org/tech-log/45283...ml#post6487728

Here is the picture that I think will help, courtesy of Hazel Nuts.
https://docs.google.com/leaf?id=0B0C...thkey=CILGt_QN

BBF has a chilling summary. It may be hyperbole, given Mieklour's experience with flying it back in Alt 2 latched from cruise altitude. :

Dozywannabe,
Not suggesting conspiracy. Just suggesting 3 entities that hoped that each other didn't get too clever or creative, too soon, as long as they all had plausible deniability. "How were we supposed to know the sub didn't know to detect 37.5 khz specifically. After all, a 5th grade science student would have known it"
I agree that malice shouldn't be assumed if stupidity will suffice, but it took France long enough to ask for help.

Chu Chu,
True. Sonar was not optimized for 37.5 khz, but if it were, it's range would have been multiplied tremendously. There's no comparison in sensitivity when tuned specifically to it, rather than listening to a broad dynamic range. Could have used a hetrodyne setup. One of those Albert Michaelson type things.

Denouement
 

Denouement

As in most such accidents, the final revelations prove to be the disclosure of a previously un-encountered but (in the aftermath) easily explicable phenomenon - and an ensuing chain of complicating and (pilot) confounding circumstances..... some of which are related to design and envelope test-flying deficiencies (but more on that later). Is it a computer-created chain of events? Judge for yourself, from the discussion below, what part the automation (or even weather) played.

After autopilot disconnect due to pitot ice-up and ADR disagree, and some ensuing pilot surprise "disconnect" (from priorities), max power was applied at or near the aircraft's cruise ceiling, the underslung engines provided a pitch-up moment that caused the aircraft to quickly climb into a stall in what's colloquially called "coffin corner". Unfortunately and simultaneously, the autotrim caused the trimmable horizontal stabilizer (THS) to motor (quite unnoticeably) to its maximum "nose-up" sustaining position. This combination of power and "back-trimmed" trim-state created a configuration that was to thereafter (i.e. during their high-rate descent) sustain a deep-stall condition that could only be entered via such a powered speed-to-height "inadvertently zoomed" scenario. Why did they add power? It's a natural pilot response to do something similar when the airspeed winds back off the clock (even though in most such circumstances it only serves to "upset the applecart" of stability).

To explain, the translatable inertia of an aircraft at height has always amazed me. When you zoom climb (even quite shallowly) at very high altitude, you are translating, into a rapidly expiring upwards vector, the very considerable energy that's there solely courtesy of its TAS - (i.e. at cruise height the True Air Speed - i.e the actual speed through the air - is roughly double the indicated airspeed ). When that kinetic energy excess is exhausted (the height increment becoming potential energy), the out of kilter aerodynamics then must dictate what follows. The resulting flight-path down from a stall in that rarefied atmosphere is a "locked-in" function of attitude and power and residual trim-state. The trim state they ended up with was the deadly legacy of the auto-trimming THS rapidly reaching max "nose-up"... as the speed decayed in the thrust-induced zoom. The power of that tilted THS slab was now enough to keep that A330 pitched up into the stall, particularly whilst under engine power. The deep-stall condition is quite a stable flight regime - and that has been known since the first BAC-111 accident almost 50 years ago (only a tail-chute deployment could have saved it). Back prior to automation it was thought to be a phenomenon only associated with T-tailed aircraft (wing-wash swamping the all-flying tail and negating its control). But since AF447 we've discovered that the A330's THS has the power to emulate this lethal configuration... but with deceptively smooth passivity.

Lacking an AoA attention-getting read-out or aural/visual alert, the pilot can only "go for" an ADI pitch attitude (and one that approximates the level flight attitude would seem reasonable to most - and it's what's been generally, but quite mistakenly, advocated here). Unfortunately in a deep-stall condition the relative airflow is not from "ahead" (but from "well below" and ahead), so maintaining (or just abiding) a notional 5 degrees nose-up "cruising" pitch is to fatally elect to live within that deep-stall's boundaries. Deep-stall is a non-alarming condition because of the lack of tail-plane buffeting. In a normal stall the empennage is being "bathed" in wing-created boundary layer separation turbulence - and it's an airframe and control feedback situation that pilots everywhere can recognize as indicative of a stalled condition. Without it you are plummeting down in an eerily smooth and silent (but non-apparent) steep trajectory.

Of course having a stall warning that only momentarily cautions an initial approach to a stall is a design that (for its pilot's alerting function) actually conceals the deep stall. Once embedded in such a stall, the aural alert ceases ("how can I be stalled, there's no stall warning?"). Any stick forward initiative (i.e. angle of attack reduction into the lower AoA numbers) only cooks off (quite perversely) that aural stall warning and increases the perplexed pilot's misunderstanding and non-recognition of his predicament ("now we're stalling with stick forward, how can this be?"). He's never seen this profile on any simulator ride. Even the Airbus test-pilots just "haven't been there" beyond the flight envelope, to test this "post departure" phase. Whatever assumptions about it were ever made? I'd suggest absolutely none. It was an area that, like max achievable Mach and IAS, is best theorized about (only). Much of what is specified for air-testing is about safe boundaries (beyond which there be dragons best left undisturbed). Airbus fails to shine torches (or even look) into dark corners of their beastly envelopes and automation perturbations.

It's no surprise to me that, once locked into their deep-stall smooth-flying regime, the AF447 pilots failed to recognize the nature of their predicament. They momentarily acknowledged their high-rate descent but due their 3-way interaction, their confusion, the smoothness of flight, the silence of low IAS, the distraction of myriad alerts, the darkness of night and lack of any other visual cues, all available cues failed to trigger awareness of any imminent catastrophe. Even the PF's side-stick grip and applied input was concealed from the captain's view. If they'd had a distinctive AoA alarm, experience of it and a laid down memory recall procedure for affirmative action (i.e. positively lower the nose until the stall-approach warning recurs (then ceases) or at least to 20 degrees nose-down), well we'd not now be agonizing over their needless deaths. It's a recognition "consciousness" trigger that's generally lacking here in our automation. As pilots of automated airplanes, we need a climactic bathos (or Eureka moment) whenever we're required to spring into an alert and cognitive state. Other interim pilot-level "fixes" (such as not TOGA'ing the power and prioritizing the lowering of the nose and using manual trim) have already been addressed in Airbus pilot bulletins.

I'd be interested in any rebuttals..... technical or otherwise. Do I think that any fixes implemented will be effective? Partially but not wholly is my suspicion. No Airbus or Air France or BEA bod is going to want to acknowledge the totality of the AF447 conundrum. AF447 will reside in the Pilot Error Hall of Infamy forever. But to allow this, without demur, would be a calumny against the profession of the professional aviator. And that's why I'm penning this. Put this out for the public and journalists to see and understand. That's how you might avert the way I see the final report going.

Hi,

DW
It does not imply any conspiracy .. this is simply to show that some people of BEA and other bodies (in good faith ?) lacked common sense and also remained deaf to certain warnings from other experts (as some has think about 447 pilots who remain deaf at the stall warning)
The results of this lack of good sens are not meaningless when you know the money trowed in and the delay for the families and also the delay for any recommendations to be issued ...
If you find that your house keys are no longer in your pocket .. will you start to look in your attic (where you go 3 times a year and last visit was a month ago) or are you going to start looking in the room you are in most cases.
And if it's dark .. do not you turn all the lights to help you see them?

Coagie. Coagie. The THS was effectively dormant for the climb. The PF accomplished the climb in ordinary and unassisted ways? He also attempted to stop it. The THS enters, stage left, basically at STALL...

The PF pulled back on the stick for a long while, causing the trim to increase so much. It wasn't just the extra thrust from the underslung engines causing the sudden climb.

Recovery?
 

Can we start a thread on how these guys could have recovered? What immediately occurred to me was to generate asymmetrical thrust to perhaps roll over, or at least enough to get into a steep bank that would lead to a nose-dive. Once the nose was really down the problem would be solved. You would need to physically understand throttle response to time things.

Eeeerm.... by pushing the stick forward?

Ladies and gentlemen, did it ever occur to you that the lift equation, Cl vs Cd curve, power required vs. power available et al. are not just some scribbling on paper or PDF that are to be learned by rote to pass the ATPL exams but extremely accurate descriptions of principles that keep us flying?

I am going on my silly sailing vacation, since I don't fly DC-4 but Q400, it will be four days instead of three weeks. I wonder what you'll make out of this thread by then.

Hash?

Fair winds and following seas, Clandestino, hope the time at sea is a joy. :ok:

(Also, suggest you avoid Eastern Seaboard of the US, seems that Irene has arrived and is blowing hard).

TheShadow

Not quite sure what you are trying to say in your post but there are so many inaccuracies in it that it was not worth the time reading it!

The discussion around CLB thrust and 5 degrees is more to do with the climb phase up to CRZ level. Below 10000' it is 10 degrees. Cruise level the attitude it is around 2.5 degrees, the NORMAL cruise attitude so there is NO need to go to 5 degrees, any thinking competent pilot should be able to work that out, otherwise they should not be in the flight deck.

When the A/THR disconnects it goes to THR LOCK and keeps the thrust set at the time until the pilot moves the thrust levers, so no great dramatic thrust pitch up is induced. The autotrim will only work to compensate for PILOT input and it went up due to pilot demand!

deSitter

There is No need to start a thread all they had to do was get the nose down. If they had held the input the nose would have gone down and the autotrim would have then assisted with a sustained nose down input. They could even have helped by using manual nose trim themselves[/COLOR], as taught in UA recoveries. As for trying to roll / yaw the nose down.:ugh::ugh:

Lonewolf

It only went dormant <60kts IAS, what manufacturer / regulator would think that a properly trained Airline Pilot would get a Transport Category A/C into a deep stall at less than 60kts!!! Having ignored the warning for >50 seconds prior to that.

iceman, you didn't answer the question. ;) I understand how it happened. Given that a pitot static system can fail and give erroneous inputs (they can, this has been known for a long time) I was asking for a defense of the design decision, considering that a number of aircraft features are routed through a weight on wheels switch ... there may be a solid answer, but I've yet to see one.

Hi
That procedure seems to have been badly phrased, as there are so many questions about it.
Anyway, I think the way its writer intended it, it was :
- if there is a danger for the flight safety => apply memory items (which is as you quoted is, 5°/CLB), then refer to QRH for the "fine tuned" attitude/thrust to apply, then manage the failure.
- if there is no danger => refer to QRH, no immediate action (i.e. implicitly, fly ahead until you know which pitch & thrust to apply), then apply it, then manage the failure.

In AF447's case, there was IMO no danger. This would explain why, as soon as june 2009, AF published a note "reminding" to its crews that they were not to apply the memory items in high altitude cruise.

For the rest (i.e. is or isn't 5°/CLB "dangerous" and/or will it or not trigger the stall warning in HA cruise), I have no clue and won't comment.

For no good reason? Two apparently very brief occurences of stall warning were observed at 02:10:10 and 02:10:13 (page 29 of BEA#3). The reason for those is clearly shown in the traces for normal acceleration on page 42 (Note that normal acceleration is proportional to AoA at a given airspeed). The purple line is the DFDR recording, the blue line is what Airbus has calculated for the pilot's control input without turbulence. At 02:10:10 the pilot pulled slightly over 1.3 g, and a gust increased that to slightly over 1.6 g. Similarly at 02:10:13 the pilot was pulling 1.4 g (increasing towards 1.5 g at 02:10:15), and again a gust increased the pilot commanded 'gee', this time to less than 1.6 g. I would expect the pilot to recognize the 'gusty' origin of the brief warnings, and he should have done nothing except maintain pitch attitude. Whether that is 2.5 or 5 degrees is really of secondary importance.

At least until we have received the final and more comprehensive BEA report in 2012, could we please not get sidetracked on Boeing v Airbus ideological debates?

The main aviation safety issue in recent years has been loss of control, with the main focus in relation to automation and the "human interface" (specifically concerns over training and the absence of line manual flying), and across all aircraft manufacturers. Even to a Boeing veteran like myself, there are only two "Airbus specific side issues" that this thread has thrown-up and neither should have resulted in themselves in the downing of AF447.

(1) The historic role of Airbus in creating the impression to line management that "planes fly themselves", even if partly inadvertently, and the knock-on effect upon the training culture.
(2) Several additional "complications" in an Airbus cockpit when things go awry, if cockpit discipline is not tight i.e. feedback issues (e.g. SS v control column, and the throttle and trimming) and the PNF is visually less aware of how the PF is by-hand flying. I suppose you could add under this heading the <60knt stall warning design "issue".

This is a training/human behaviour issue otherwise the temporary UAS on AF447 would have been temporary by-hand P+P flight and another logbook entry on the Thales pitot tubes being phased out......

Not quite the same thing, but remember Cessna's "Drive it up, drive it back down" advertising campaign of the 1950/'60s?

Well, let's be fair here - if they'd asked the engineers rather than the sales guys they would have got a more honest answer going all the way back to 1988. As a slightly tangential aside, aircraft manufacturers have been claiming the ability of their aircraft to "fly themselves" to some degree ever since the introduction of INS-enabled autopilots - in fact the first time I ever heard the term used (albeit in a fictional setting) was as an annoying kid watching the annoying kid in "Airport 1975" saying the very same thing about the 747. I'm sure the Boeing sales team would not have gone out of their way to qualify that remark. And the movie, though utterly terrible in any kind of objective sense, certainly demonstrated via some rather nifty stunt flying that the 747 was very stable in environments where it would never normally be used.

Another quasi-fictional allusion to said ability crops up in John G. Fuller's "Flight 401" book, this time in reference to the L-1011 - and no matter what you think about the supernatural bobbins included therein, he did his research on aircraft and line operations pretty well.


Not completely unaware, mind... PJ2 confirmed a few posts back that most of the FBW Airbus pilots he knew didn't really see the feedback thing as an issue.

My interpretation of the CVR, for what that's worth, is that the PNF saw what the PF was doing by watching the attitude of the aircraft on the ADI, but for reasons that are likely to be endlessly debated in human factors forums for years, he either failed to accept that the guy to his right really was mashing the controls about that cack-handledly* (would you, or any pilot on here for that matter not have a moment of "this can't be happening"?), or indeed came to that conclusion but again, for reasons that will be debated for years, felt he didn't have the authority to tell his colleague to get his hands off the d*mn stick right now. We've seen instances of this before, with KLM4805 at Tenerife and Birgenair - but previous instances have tended to involve an F/O who felt he couldn't overrule his Captain. With a poorly-defined command gradient, is it possible that an F/O can also feel he or she does not have the right to give orders to a colleague of the same rank?

Also, I don't think flight deck discipline and airmanship in general can be completely separated - if you don't maintain proper CRM and organise your flight crew effectively then you're probably going to end up in the cacky eventually no matter what aircraft you fly.

Fair comment, but as of now we don't know how many other types also have the same issue or similar. I'd be prepared to bet money that it's more than a few... One of the perennial issues that has dogged stall warning technology in jetliners since the days of the Comet, Caravelle, 707 and DC-8 is the number of hull-losses attributed to the crew incorrectly diagnosing a stall warning as false when it turned out not to be. I find it hard to fault any manufacturer making a design assumption like that because this is the first time in decades that an airliner has ended up so far outside of it's design parameters.

Absolutely agree. Though having said that it offers intriguing technical questions about all modern fourth-generation airliners - and I wonder if Airbus and Boeing will be willing to examine their designs to see what potential gotchas lurk when the aircraft is taken that far outside of it's envelope.

* - I happen to be cack-handed/southpaw/lefty, so I can use that phrase. ;)

Welsh - a good summary, I would, however, make the stall warning item the third type-related issue, and really what other types/manufacturers 'do' or 'did' is not relevant to this occurrence.

As others have said, 2.5 deg/5 deg.emergency/non-emergency - no matter, none would have caused this crash, but 11deg did initiate it. There are enormous holes in the 'French' cheese in this accident, and Dozy sums up the HF neatly in his middle para. I am still greatly puzzled by the lack of assertiveness of PNF.

Lots of new cars for the lawyers.

HN39;
BOAC;
I agree with both these statements.

DozyWannabe/BOAC
 

(1) To be fair, I have added "inadvertently" to point the "blame" in the sales direction. I am acutely aware that Airbus's head of training had a battle just to keep training at pre-existing levels (discussed previously by PJ2, on the main AF447 threads), when heavy automation is basically "existing airmanship plus".

(2) I was intrigued by PJ2's comment on this aspect, as he is an AB veteran. Takata has set out the AF command structure in place at the time of this incident and facing the CDB, which was not ideal for any "unhappy" PNF in the LHS without the "unsatisfactory" handover on AF447. Would the PNF have been more assertive if he could have seen what the PF was specifically doing through a clearly visible RHS control column (or at least if the LHS SS was moving in tandem with the RHS SS movements commanded by the PF?)? The throttle moving also? Would the PNF at least have been better placed to properly brief the returning CDB? Might this have overcome CRM shortcomings and saved the day?

(3) "Design assumptions" are always dangerous. The Titanic was "unsinkable" because how could White Star possibly flood the first five watertight compartments.....? What floats, can sink. What flies, can stall. A stall warning really should stay on until an aircraft is no longer stalled. The stall warning ceasing just after the CDB returned to the cockpit was, at best, "particularly unhelpful".

(4) We Brits naturally prefer "evolutionary", which is why I value PJ2's viewpoints on the more "revolutionary" aspects of the AB design philosophy. From Stony Point through Aeroperu and Birgenair to Colganair, there are stall warning issues and pilots forgetting their training and grimly pulling back on their control columns. Post-Stony Point, was the industry ready for another system? AF447, and the ignored stall warnings, tend to suggest not I would submit. Hopefully, with control column pilots now acutely aware of the "stick shaker" issues after numerous hull losses, there won't be a SS repetition.

As I said, I don't want to get dragged into any AB particular issues.

This is an across the board training issue. The less routine manual flying that pilots do on any aircraft (within the flight envelope), the harder it is for them to suddenly "ride to the rescue" in a degraded flight envelope emergency. That must be self-evident........

apropos not much,; had the crew recovered, the landing back at CDG would have been interesting, especially in a crosswind.

I know, just thought I'd reinforce it for the benefit of non-native English speakers who may not pick up the inference as easily as I did. :)

Well, that's a difficult question - and as I said, one that the human factors bods will be debating back-and-forth till kingdom come. Common sense suggests that it might have made a difference, but on the other hand there's the CVR that suggests that the PNF might have been aware that his colleague was overcontrolling even without feedback, as well as the historical cases (Birgenair, NWA) where the PNF in both cases had the yoke in front of them reflecting the PF's inputs, and still failed to put two and two together.

Of course they are, but as I'm sure you're aware, design and engineering are and have always been underpinned by the art of compromise. In this case (as I said above) there was a history of incidents where the number of false stick-shaker events led to an assumption on the pilots' grapevine that most stick-shaker events were false, with fatal consequences when a real stick-shaker event happened. Manufacturers were then faced with the task of weeding out the circumstances in which the stick-shaker was a false alarm, and Airbus's logic was based on a set of parameters that were so outside the flight envelope that they couldn't see it happening with the aircraft aloft - it's possible other manufacturers have done the same and at the risk of repeating myself I hope they all band together to find out.

The Titanic (another minor obsession of mine as it happens) and the Comet 1 were both examples of designers working at the limits of contemporary knowledge (regarding worst-case maritime collision scenarios in the former and metal fatigue in the latter). Now we know that it is possible to stall a modern airliner to such a degree that it intersects the stall inhibition parameters, it's likely that designs are going to have to change.

Now my old Prof considered the A320 more "evolutionary" than "revolutionary" once he got to poke around inside, the only difference being that the aircraft it evolved from (the A300/A310) was already probably the most technologically advanced airliner flying up until that point (though again, as I said before, the L-1011 came close). It depends on how you look at it - most of the circumstances that made two large, connected central control columns necessary in the first place (largely to do with leverage when the flight surfaces were directly connected by cable) were no longer applicable by 1972, let alone 1982 when the A320 was being specified.

Aeroperu was slightly different - loss of pitot data affects airspeed indications, and as long as you click the A/P off, it's relatively straightforward to manage. Aeroperu had the static ports taped over, which was a whole other ballgame in terms of what it did to the instruments.

Fingers crossed!

Absolutely - but the pressure must be brought to bear on the airlines, specifically management, that the status quo is not on, and again - as I've said before - who will be the first to stick their head above the parapet?

BOAC
 

Given that he was CATOBAR trained on the BBS1 and the BBS2 for the old Ark and Eagle, I suspect the Wingman has very decided views on the AoA going to 0 and ceasing the stall alarm at less than 60 knts and is showing remarkable restraint in keeping his views to himself......

Iceman50,

Trying to get the ND, is only the beginning of the first part of a Stall Recovery.

There is more to Stall Recovery than that, and I read "deSitter's" post, as a suggestion on discussing all parts or aspects, and as far as I am concerned that seems to be an interesting idea.