The Lord has spoken.

A33Zab is more reserved that you are :
Maybe IF SS feedback/interconnection was available it would not have happened.

I certainly don’t see as necessary to go back to the "old" technology.
What is more sensible and necessary, is to openly discuss what the sidestick Airbus concept has suppressed. It is the role of Airbus, it is the responsibility of the BEA. But Old Carthusian can sleep well, never the BEA will approach the subject, far too sensitive, and if ever they do at my great surprise, it will be to better discard it as a contributory factor.

... Report in June ?

Classic straw man argument - no it doesn't, because not only are those warnings necessary, but also there are plenty of incidents where they *have* worked. I'm sure there have been plenty of incidents where the override system provided by the sidestick design has worked to resolve a situation as well.

There is an argument for limiting the number of warnings at any given time - because of the Aeroperu and Birgenair cases, where the numerous and conflicting visual, aural and yes - tactile (stick shaker) warnings only served to confuse the flight crew.

I know that there's a lot of belief in some circles that the Airbus design was a deliberate attempt to design the pilot out of the loop and eventually out of the flight deck - this simply isn't true and never was. All the information you get from a traditional flight deck is there in some form or another, and if not, alternatives are provided. You may need to access that information in a different manner, but it is there, should you choose to use it.

No-one has even attempted to answer the question as to how the captain failed to deduce a stall situation despite the information right in front of him - asserting instead that if only the A330 had yokes he would have been able to. There's no evidence to back up that assertion, only supposition that it "might" have helped. The evidence available from similar incidents suggests that it's just as likely that it "might" not.

In a situation which is outside the realms of SOP and checklists, a good, professional aviator should use the information and tools available to resolve things. All the evidence suggests that enough information was there to do so, and the tools to do so provided. The yoke argument is a red herring here.

Hi DozyWannabe,
I'm glad you raised this one because it perfectly shows what happens when the crew don't realise how much aileron is being applied to satisfy their roll request. They both applied full roll side stick, but because it was in ground Law - they only got half aileron (above 70 kts)!!! ???

From page 46 of
http://www.bfu-web.de/cln_030/nn_226...indlanding.pdf

"The aircraft touched down shortly after the 1,000 ft marker in the touchdown zone, about 2 m left of the runway centreline lights with the left wing 4° down and the fuselage pointed 2° to the right of runwayallignment, whereupon the rudder pedals were returned to the neutral position.

The aircraft yawed towards the left, thereby increasing the lift from the right wing and decreasing that from the left wing. In spite of the co-pilot's right sidestick correction, this resulted in unintended contact between the downwind main landing gear and the runway. The objective had been to land with wings level. This was confirmed by the correct application of right sidestick prior to touchdown, which was intuitively supported by the Captain's sidestick (dual input).

After touchdown the aircraft yawed a further 5° to the left. The left main landing gear lost contact with the runway. At no time did the right main landing gear make contact with the runway. Lift dumpers (partial spoiler extension) remained inactive, because the necessary prerequisites were absent.

During the next few seconds the aircraft rolled to a 23° left wing down attitude in spite of the full right deflection of both sidesticks and application of right rudder. The switch to Ground Law limited the effect of roll control corrections. The left main landing gear again made contact with the runway. At about the same instant, the left wingtip made contact with the runway."

Page 48 "The investigation showed that the pilots could not have been aware of the crosswind flight control characteristics in close proximity to the ground and which were dependent upon the aircraft design. It is impossible to clarify whether the pilots would have taken a decision for a go-around procedure earlier had there been a risk evaluation that included aircraft system behaviour, then unknown to the crew, in this wind situation with the possible effects of gusts. The BFU is of the opinion, that the respective knowledge would probably have influenced the decision."

I know. It doesn't alter the fact that there shouldn't have been a DUAL INPUT situation in the first place. Even if they didn't go around as soon as stability was lost (which was the best case scenario), the captain mishandled the procedure for taking control.

It was a high-pressure situation, so it's understandable that instinct overrode training. However, despite assertions to the contrary, there's no guarantee that the outcome would have been any better with yoked controls - in fact if it had triggered a startle response in the F/O it may even have been worse.

@CONF - you do realise that the accusation of arrogance you're levelling at A33Zab for saying what he's saying can also be levelled at you for insisting that yokes solve everything and are an objectively superior control method, don't you?

Hi DozyWannabe,
Well I'm afraid we'll have to disagree on that one.

On the TriStar, operating to Bermuda with strong crosswinds and only Island Holding fuel, we would sometimes have to land in limiting crosswinds. If we attempted to align fully with the runway using rudder, we could feel when we were about to run out of aileron control (by the position of the yoke), so we would have to relax the rudder slightly and accept touching down with more drift.
(& full aileron control was available on the ground, even above 70 kts)

None of that feed back is available with Airbus FBW.

The fact that they got reduced aileron control on landing was not due to DUAL INPUT - it's simply a function of "on ground" mode.

Logic Problem
 

DW:
Some of us are heartily sick of this failure of logic of yours. OK, I am! :O

Few, if any, have said anything about it being "superior" or would "solve everything." And you talk about straw men! I, and others, have said until we are blue in the face, (like this): :confused: that it MIGHT have helped. WE can't prove that it would have, and YOU can't prove that it wouldn't. This is simple logic. Very experienced pilots here have opined that it might have helped. You are fighting a battle that you just can't win; give it up, man! This issue is the MAIN thing causing the hamster wheel to go around endlessly. No one will ever know if it would have helped.

As an educated SLF, When I am riding in the back minding my own business, I expect that EVERY POSSIBLE SAFETY MEASURE is in place (if it were not prohibitively expen$ive). Not rocket science. You sound like one of those accursed bean counters, or else there's some sort of bias that we don't know about. /rant

Where are you going with that one Dozy ... ?

Accusation of arrogance towards A33Zab ??? Please explain.
Where do I insist that yokes solve everything ? Please quote.

Sidestick Airbus concept suppress information of great value for a crew : It is a fact. You can quote me on that one.

You say "suppress", I say "supplies differently where that information is indeed necessary". The flipside is that the sidestick system comes with safety features and benefits that are not available with interconnected yokes - this is also a fact.

@Organfreak - as many very experienced pilots have opined that it might not make a difference as have that it might. This isn't a "failure of logic" on my part either, I know full well the posting histories of some of those I'm talking to - some of them have outright accused Airbus of being in cahoots with airline beancounters to sideline pilots. People asking "why won't they interconnect the sidesticks?" not only seem wedded to the idea that interconnection is a positive in *every* case (it isn't) - but, as importantly, don't seem to have grasped that interconnecting the sidesticks would defeat several safety features inherent in the design.

Regarding "every possible safety measure" being in place - interconnected yokes are *not* a safety measure by any objective standard. I know you're a Boeing man, but give a little ground here, eh?

Requested response
 

B44:

It wouldn't let me link to page 72 (Spoilers), but once you get it open go right to page 72. :)

B 757 General Familiarisation in Maintenance

(Sorry to interrupt CONF :))

DW:
No, you don't.

I'd swear you'd said something along those lines previously - I may be wrong, and happy to be corrected. I'm sorry if you're offended by anything I've said - but I don't like situations where all the cards aren't on the table.

You asked if I have a bias? Yes I do - I am biased towards lack of bias, objective criticism and dispassionate observation, nothing more. If a very experienced pilot, or anyone else for that matter, says they feel uncomfortable about the lack of tactile feedback inherent in the system - that's their call and I won't say a peep. If they say on the other hand that tactile feedback is inherently safer with no concrete evidence, then I'm likely to refute the statement. If they are unaware that the design of the system has safety benefits that the traditional yoke does not, I'm well within my rights to point that out.

The fact that Airbus and Boeing share around 50% of the market each and have done for over a decade with no statistically significant safety discrepancies between them proves conclusively that whatever the benefits and drawbacks are to their control designs, both are valid and safe ways of doing it.

Kneejerk calls to change the sidestick system's design based on one possible factor in a single incident are wrong-headed and ludicrous, and they only ever seem to go one way. No-one went round suggesting that Boeing retrofit the 757 with sidesticks because the Birgenair PNF didn't do anything when the aircraft was stalled - why should it be any different with the A330 and yokes because of AF447?

My sincere apologies to rudderrudderat for not attributing my quote in #407 to him, in 406.
PEI_3721 :

"With the lack of an airspeed display, a FBW aircraft has no backup of sensed trimmed position as with a conventional aircraft (no stick-force for trim speed error), thus it is important to look at the physical trim indication and be aware of the need to null any stick input when the desired flight path is achieved."

I was not focused on Stick force, per se, but on the lack of awareness PF had of his Pitch... To lower the NOSE, he has to overcome the springs, even though the a/c cooperates fully, (or would) in his command for descent(s)? IOW, and this sounds disrespectful of him, but is he "mistaking neutral for level?"

One assumes he was better treated in ROLL, as he seems to have sussed DIRECT LAW re: ROLL rather quickly. How is it his inputs were fundamentally on in correction angle, (only in rate did they alarm, and that soon settled out).

So, unfamiliar with "miss twitchy", he does a splendid job (DW, PJ2). (I disagree, ROLL remained a serious issue). Yet in PITCH, g controlled, he screws up quickly and chronically..... Do his actions, that result in "Level" (though climbing) emanate from sussing a "new normal" each time he lets up on Back Stick?

What are the two looking at, if they had attitude, how in GOD's name do either one not see the Nose well into blue? And what do you make of the conversation re: trend? I cannot figure what they refer to as trend, does "going up?" mean positive ROC? Or does it mean "inputting a command for climb?"

I think the allusion to ab initio (or medial) reversion is sound. He is a glider pilot, and cannot fly 330 as a Schweizer....

Maybe stop creating stories of your own, then you won’t need to fight them.

DW, any chance you assume those statements at least, or is it free speech again with no backbone ?

After analyzing hundreds of messages including the elements trying to show that the pilots are not fully responsible for the accident .. I conclude ( the sad reality) that none of the explanations fail to hold harmless the lack of professionalism of the pilots
Since setting up deep stall to the imposibility to recover from it .. is comparable to performances of poor beginners despite their experience (their licenses of liner pilot and flight hours on paper)
I can compare them (their piloting skill) to the September 11 terrorists .. but them .. despite their poor piloting skill and inexperience on type .. they have completed their mission that was to kill people
The mission of the Air France pilots was to save people .. and they have not fulfilled their mission
Maybe crude and rude .. maybe some think like this but don't speak of it .. but after all ... why not ?

My friend, I hope you reconsider. The two things are not even alike, at all. We already have many helps to explain what happened, and although it seems the pilots were somewhat at fault, you must consider what you say. There was no evil on board or on the ground in connection with the tragic loss of 447. I am angry with some involved with crash of AF, but they are humans, too, and likely suffer with the rest of us....

Take a breath mon ami.

jcjeant: Wow.

Lyman;
How and in what way does a roll to a bank angle of about 8deg either way "remain a serious issue"? I'm referring of course to "Phase 1", which is from the initial UAS event until the onset of stall-warning or the apogee.

The evidence that the PF got the roll under control quite quickly is in the data - it is a series of diminishing oscillations - a stabilizing (reducing) pattern of divergences, between left and right.

Now, as the AoA increases and lateral stability decreases, roll commands increase again and along with everything else roll becomes increasingly unstable, but all this occurs after the stall warning and just a bit later, the stall at apogee.

Even if there is some incidental pitch up command, both pitch and roll are eminently controllable with small movements and a normal response to an incidental pitch-up which is not desired, (for sure, not at FL350).

Ideally, one flies the airplane, which here means that the pitch is lowered and stick movements subside, (stick held fast), while the mass of the airplane settles down in the thinner air, then one returns to cruise altitude, etc.

th to go, then with renewed vigor....
 

My take is that as well as PF did in his containment of his initial overcontrol in ROLL, he was unable to sense a neutral, in PITCH attitude. I would have expected that due to DIRECT LAW in ROLL, it should have been the reverse.

Simply put, PF was chronically either a) seeking to slow, or b ) seeking to avoid a descent. What other than those two would explain a chronic UP input? You point to his remedy of ROLL in "Phase 1". Later, with excursions in ROLL of over 40 degrees either side, he kept the bird from turning over. Again, a "mastery" of lateral. But an acute misunderstanding of PITCH.

Do you expect any surprises in BEA "Final"? I think most everything was anticipated at great length here. Do you think they will address UAS in full, for instance, discussing loss of Radome? How in depth will they go in analyzing the vagaries of the newest nemesis " Microcrystalline Water Ice"?

Will they rehash the badness of reselecting AutoPilot whilst in NCD?

A month to go, then with renewed vigor.....

all the best,

Lyman;

Some edu-guesses - they could be way off base, but an attempt...

The airplane is more sensitive in Alt Law in roll but once one gets used to it, it is controllable using tiny inputs. Being unable to sense a neutral point would be difficult because it is strong enough in the SS to feel it, but if distracted or under pressure, perhaps not as easily. The way to find the null in either yoke or SS is to let go of the controls for a moment - in most cases nothing immediate would occur and one starts from the null point. The airplane is less sensitive in pitch, but in pitch one is changing the trajectory of the entire mass, and in thin air, whereas in roll, one is (in the immediate sense), not asking anything more of the airframe than a change in bank - other than the engines, fuel and wing-structure and some resistance from the vertical and horizontal stabilizers, one isn't immediately changing flight-path which requires much more work. Just edu-guessing here...remember, I'm not an engineer!

Possibly - this has been discussed at length in thread 2 or 3. The baro alt decreases about 300ft initially then recovers quickly - it did this in the Air Caraibes event as well. Seems a characteristic of this event. Even if this was an over-reaction by an inexperienced-at-manual-flight-in-cruise pilot, (and there, most of us are the same!), it is easily controlled by gently pitching back down and settling the mass of the airplane. But no. The pitch continued to increase. There is lots of blue on the PFD, and one should be getting very (very!) twitchy where one's behind meets the seat if you get my drift - high pitch angles at cruise are an instant "full-alert" & "get it down", now, kinds of occurences.

On pitch, I suspect right after the apogee and by the time the bank angles were reaching 40deg, (only at one point in the descent), a differently-developing psychological state began overtaking the crew, esp the PF. It is well known that high stress exhausts intellectual resourcefullness and perceptions - this was mentioned in the Alaska Air 261 MD80 jackscrew accident off LAX. I think this would be addressed in the HF section of the Report. A rational assessment of pitch was perhaps less possible as a visceral, self-preservation response developed from a state of increasing loss of SA - the solidly-held up elevator occurs twice in the descent and for a protracted period of time. The same phenomenon was recorded in the Airborne Express DC8-63 stall accident in 1996.

I think the surprises will probably be in the emphasis the BEA places on various aspects of the accident and not in what may or may not have been missed. There will be absences in the report that will be puzzling to some I suspect but that comes from one's particular POV and not necessarily from the importance of one or another aspect of the accident. The three IR's are thorough, particularly the third and address HF/Ops matters such as SOPs, CRM and so on and I think that will be the most examined. It is reasonable to consider that the stall warning, AoA indicator (raised in the Airborne Express accident), and THS items will be discussed but it is hard to say how, primarily because the airplane performed as designed and certified. It will be interesting to see if the sidestick issue is discussed. I think it will be minor if at all, primarily because it remains a demonstrably successful design and there are some counter-examples where the yoke design hasn't prevented the stall or crash, and because the expectation that design engineers cannot be expected to design against all possible circumstances. Something like that anyway...it's all a guess.

I hope the UAS issue will be addressed from a number of viewpoints. As you know I think the drill and checklist are poorly-crafted, poorly-trained and to put it simply, confusing. There are a few documents which have surfaced over the past year or so that put meat on this memorized drill and read-do QRH checklist so perhaps with such supporting training it's okay as written. The FCTM emphasizes items that are not at all clear in the drill. I think the PF was executing what he knew from a previous sim which was the memorized drill just after takeoff which is entirely the wrong thing to do at cruise altitude but this isn't clear as evidenced in the discussion in thread 5 or 6. I've had a go at re-designing it and it seems to work but there are always considerations that at first aren't obvious and maybe the drill as-written is still the best. I think the pitch-up was intentional and it rapidly confused the PF and the PNF did not take action, did not challenge what was happening and did not stop it, which, to me and many others, would have been obvious once seeing a pitch attitude of 10 - 12 degrees at FL350 so I think there is a cultural thing (broadly HF) here that will show up in the report. This has already been mentioned with regard to two F/O's, cockpit gradient, Captain's briefing etc.

There was no loss of radome until impact so it won't be discussed.

I think the discussion of ice formation and loss of pitot function will be extensive, as will the pace and decision-making process regarding actions and replacement prior to the accident. I think it may be a summary of thinking and design changes already done. But also it deserves the same kind of treatment say, that the ice-formation in the Trent 900 received in the BA777 Report.

I think also there will be questions/comments for all parties regarding awareness, training and checking given that the industry had had thirty-odd UAS events in cruise yet it didn't appear to be making them a part of recurrent training. I never once saw any such abnormal in the sim yet they were out there, post-1996. Other already-required scenarios may have crowded out the time needed for this but it was a demonstrable threat which, to me, was not handled in the way we ourselves are trained when we are doing threat-and-error management in the cockpit. I can't ever recall it even being discussed.

I can't recall - did the crew do that and was it potentially a factor? Regardless, I suspect it won't be discussed except in passing. The Bulletin was issued and is part of SOPs.

Quote:

---

"A month to go, then with renewed vigor....."

---

It's an extremely challenging report to write - I think it will be longer than June but again, a guess. I suspect the translation will be even longer still.

Reason for the right turn after the stall
 

I've been dinking around with this and here is what I've come up with on the right turn after the stall (after all, why not a left turn?)

First, there was no "uncovered setting of the rudder trim that became exposed by Alt2 as I had earlier suggested there might be.
The autopilot has authority to trim the rudder in the same way that the pilots can and did so a number of times up to the AP disconnect. It was with the last A/P rudder trim setting that AF447 did its descent.http://home.comcast.net/%7Eshademaker/AF447Yawtrim1.jpg
Before the AP disconnect, there are some small trim adjustments on the order of 0.2 degrees. ranging from -0.25 to -0.5 degrees. After the AP disconnect, there are some small blips in the trace, but the indications remains as before. The position moved to -0.4 degrees seconds before the AP disconnect and that is where it stayed. -0.4 degrees has the effect of being a slight right rudder input. The reasons for the blips in the trace are unknown, and are most likely caused by noise on the circuit, or mechanical slop in the indicating system.

The effect of slight rudder trim would be minimal until the AOA began to run up, at which point, it would cause a preference to drop the right wing in a stall. The turns that are observed after the stall would then result from this preference plus pilot inputs on the rudder.

This probably repeats the evaluations of others, but now is my own.:O

When I pulled the clean F-4 into a stall and held it there, the aircraft would drop off on a wing. If I then applied opposite rudder gradually increasing, it would then flop over on the other side without being able to stabilize it even momentarily in a wings level mode. If I continued doing this ruder exercise, the aircraft would reverse itself yet again ever more violently. This is the experience I use to explain the AF447 post stall behavior although the A330 has a very docile stall by comparison.