AF 447 Thread No. 6

[HarryMann]

It doesn't require the complex system to in fact break, or for you to forget your training, to introduce the possibility that a stressed human mind trying to start to appreciate an unanticipated possibility never achieves sufficient confident to diagnose and then act. The awareness of a complex intervening layer is in itself sufficient to frustrate intelligent problem solving, at least in a timely way.


Something to consider, for sure.. that intervening layer is always a 'head' problem

A 'big red button' which forced direct law, with direct law behaviour a set of memory items, would seem a reasonable last resort to offer a bemused crew.

Not forgetting appropriate display of unusual trim conditions and cancellation of any warning cancellations, naturally.

Radical, but reasonable

[Lonewolf_50]

Dozy, is it your position that only the PNF was operating under the awareness that the aircraft was in Alternate Law? I do not think that what has been released from the CVR supports that position. As a number of others have noted, we have no access to various non-verbal communication that went on between them.

Further that point, given the difficulty PF had initially with roll control, one can be fairly certain that he was all too aware that he was in Alternate Law.

The more cogent point made is what BEA seems to have addressed in its findings of how and what preparation, training, and comfort with flying in Alternate Law at high altitude the crew had to fall back on. One could couple a "recency of training data point" to link to the choice to select TOGA ... which takes us back to Lyman.

If his mindset was overspeed, applying TOGA does not seem to fit the problem he was trying to solve.

[Diagnostic]

@Lonewolf_50:

I'm not trying to reply for Dozy, but I wanted to add a comment:
Dozy, is it your position that only the PNF was operating under the awareness that the aircraft was in Alternate Law? I do not think that what has been released from the CVR supports that position.
IMHO the lack of an acknowledgement by the PF (according to the CVR transcript) to the PNF calling Alternate Law does leave open the possibility that the PF had not really "heard" that statement.

If his mindset was overspeed, applying TOGA does not seem to fit the problem he was trying to solve.
Agreed, but later he deployed the speedbrakes, which therefore does fit with an overspeed mentality. My view is that the PF's mental picture may have changed (perhaps multiple times) during the whole event sequence, which would therefore explain the seemingly contradictory actions - they were not contradictory at the time he did each one, as his mental picture of the situation had changed in the meantime.

In other words, if we consider that he may just have been trying several different actions because he didn't have any confidence of his diagnosis, then it is perhaps easier to understand why, during the whole event sequence, he did seemingly contradictory things like TOGA and later speedbrakes.

That's my current "model" to try to explain the PF's varied actions. Does this make sense as a possibility?

[Lyman]

Diagnostic

Yes. It is possible PNF was alerting PF to AL with loss of RAS, as a second, and more determined way of getting the PF in AL 'mode'. Most of PNF's comments were of this type: "Watch out..." "Less Lateral..." "Loss of speeds......Alternate Law". He was, if not the scold, the short fused "instructor", albeit seemingly with good motive.

Yes, again. PF's seeming variable mind set re: overspeed/STALL occurs in a domain where they are not radically different in value. At least initially. We must not forget that the aircraft at a later time warned him of impending STALL each time as he was about to recover. We do not know yet, but at many times post a/p loss the a/c and PF were at odds, as PNF was with PF. Finally, with the arrival of the Captain, who seemed of no use, was there any time after the loss of autoflight that any one was on the same page as the others?

With such a fundamental lack of basic airworthiness, it at times seems bizarre to focus on details...... To what effect?

He did deploy brakes. He was ready to a second time, in presence of Captain, when Captain said "No, do not use brakes". For all we know, it was the lack of a complete stow of a starboard side spoiler that caused the chronic Right Wing drag/drop.

Do we know exactly when Alternate Law 2 selected?

[RR_NDB]

Hi,

Diagnostic

My view is that the PF's mental picture may have changed (perhaps multiple times) during the whole event sequence, which would therefore explain the (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-50.html#post6722353)seemingly contradictory actions - they were not contradictory at the time he did each one, as his mental picture of the situation had changed in the meantime. In other words, if we consider that he may just have been trying several different actions because he didn't have any confidence of his diagnosis, then it is perhaps easier to understand why, during the whole event sequence, he did (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-50.html#post6722353)seemingly contradictory things like TOGA and later speedbrakes. That's (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-50.html#post6722353)my current "model" to try to explain the PF's varied actions. Does this make sense as a possibility? (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-50.html#post6722353)A lot of sense considering he was always trying to "understand".



(http://www.pprune.org/report.php?p=6722353)

[jcjeant]

Hi,

You know .. PF's actions may well be the result of his ignorance of the phenomenon that came to him.
His state of mind can be that of someone who does undestand nothing of what happend
And therefore he will do actions that are actually testing and according to results .. do other activities .. hoping that one of them will be good to solve the problem he could not analyze
OT .. but ...
This reminds me a auto crash stop on a diesel generator
The group suddenly stopped and the engineer in charge has undertaken many tests dismantling and replacement parts
Having to resume investigations .. I immediately understood by examining the log data measures engine parameters. that something unusual had happened at the oil system (temperature and pressure)
An worn lubricating oil pump was the problem and not the fuel injection system and turbo blowers that had been dismantled ...
The other mechanic was therefore not understood and therefore tried anything
If he was lucky .. it would have started with the oil system ..
This was not the case ....
A loss of 8 hours of time and money .

[Lyman]

In an emergency, not knowing what to do comes from not knowing what you face. Not knowing what you face is caused by a lack of, or misleading, cueing.

It is not helped by not knowing what one should do if one knew to do it. That is not aided by having to read something to try to understand what it is one does not know. If three of you do not know, the airplane will do what it does, whether you know what that is or not.

If you do not know what the airplane is doing, you should be home playing rummy. If the airplane is coy, or misleading, that can be judged as lack of skill in understanding what it is supposed to do, unless something comes up that the aircraft cannot do, in which case the three who do not know will be blamed for not doing what they didn't know to do in the beginning.

The fact that the airplane and by proxy her designers, did not know, is not important, for they are not present, only the evidence of their work is.
The mistakes they made can be corrected with new work that can be added to the aircraft and utilised until the aircraft once again comes across something it cannot do, and the pilots will be required to understand immediately what it is they do not know, and most likely were not carefully taught.

Repeat........

[RR_NDB]

Hi,

Mr Optimistic

A 'big red button' which forced direct law, with direct law behaviour a set of memory items, would seem a reasonable last resort to offer a bemused crew.Not forgetting appropriate display of unusual trim conditions and cancellation of any warning cancellations, naturally. (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-50.html#post6722032)

Dificult to imagine a change in their minds to implement this (very reasonable) last resort. :E "Collision" of K.I.S.S. x K.I.C.S.

Complex Systems can deliver, at certain situations, Stupid outputs. Again the old "Testability issue" of Complex Systems.

[Diagnostic]

@ RR_NDB and jcjeant:

Agreed, yes - one interpretation is that the PF was basically "trying things", to see what happened, at least on some occasions (e.g. the speedbrakes). I had written something very similar in an earlier draft of my posting, but I deleted it, to try to be brief :) So we're thinking along similar lines, I believe.

From that standpoint, the various actions from the PF make a little more "sense" IHMO. If he was indeed in that "let's try X and see if it helps" mode, then perhaps the intermittent stall warning helped to drive & reinforce exactly the wrong actions from him. As I think most people agree, on some occasions, it seems that he stopped doing the correct (ND) inputs, when the SW started to sound, as if he was "testing" his ND actions, to see if they helped, without the real "belief" that this was the right thing to do. (Before anyone says it, yes, I know this doesn't explain the lack of apparent recognition / acknowledgement of the 50+s of continuous stall warning initially. :confused: )

@jcjeant - re your OT: I have seen many similar examples of that type of poor troubleshooting too :( Yours is a good example of someone guessing at a (wrong) diagnosis, and not confirming that it explains the available data (e.g. oil temperature & pressure). Thanks for that story.

[Lyman]

Won't "They" merely repeat that Direct Law is available anyway? Why the Button?

Wouldn't "They" be correct?

As far as cancelling the cancellating logic and eliminating the current obligatory autotrim into STALL, and adding BUSS (they did), and a workable AoA cueing system, that will be done, assuredly. But it will be acknowledged as "probably not really necessary anyway". Won't it?

I suppose in the end, after all is said and done, arrogance is not that lethal, the statistics show us that. Don't they?

[mm43]

When the PFDs are changed (as per A380) to provide conclusive evidence of where the side-stick is, who has got control, along with rudder pedal position and AoA indication - then the "big red button" will be redundant.

http://oi54.tinypic.com/33pap6q.jpg

If the AoA scale is colored "red" to the top, one would need to believe you are stalled. SS down while keeping wings level and get the nose down and keep it down until the AoA is back under 5 degrees.

On the otherhand, with PFDs as shown above, you'd be hard pressed to get the aircraft into a stall. "Human Factors" notwithstanding!

[RR_NDB]

Hi,

mm43 @ #1005

...then the "big red button" will be redundant. (http://www.pprune.org/6722631-post1005.html)

I would prefer to decide when to use the last resort. My understanding of "big red button" is of a resource not offered automatically by the System. A resource to be used when i decide to "fire" the System. Then starting to use the System just to provide what i will need to "hand" fly the a/c.

The "reconfigs" after that could (should) be implemented gradually, eg THS, etc. and presented to the crew.

[CONF iture]

When the PFDs are changed (as per A380) to provide conclusive evidence of where the side-stick is, who has got control, along with rudder pedal position and AoA indication - then the "big red button" will be redundant.
mm43,
Correct me if I'm wrong, but I don't think it is how the 380 is equipped ?
To me it is more the kind of Animation you can obtain from FDR data.
What is seen as "big red button" is a simple way to force Direct Law and benefit from a more 'conventional' aircraft.

[Lyman]

The concept of leaving AB Flight Laws behind, and with the select of a button, at that, is an odious proposal.

It infers that the simple, "DIRECT" method of flight control is superior to that of laboriously designed degrading (cascading?) electronic systems that are inferior to manual control in certain situations: THEY ARE.

This is all about PRIDE, and TURF, and MARQUE.

Nothing to do with flight control, or safety.

[Lonewolf_50]

Diagnostic.

Agreed, but later he deployed the speedbrakes, which therefore does fit with an overspeed mentality.
Later, yes. Agreed.
My view is that the PF's mental picture may have changed (perhaps multiple times) during the whole event sequence, which would therefore explain the seemingly contradictory actions - they were not contradictory at the time he did each one, as his mental picture of the situation had changed in the meantime.
Yes, that is a very good way to present the event from his perspective. He kept tyring to fit what was happening into a mental picture that he recognized. It seems he never succeeded.
In other words, if we consider that he may just have been trying several different actions because he didn't have any confidence of his diagnosis, then it is perhaps easier to understand why, during the whole event sequence, he did seemingly contradictory things like TOGA and later speedbrakes.
Yes.
That's my current "model" to try to explain the PF's varied actions. Does this make sense as a possibility?
Makes a lot of sense to me. :ok:

[mm43]

CONF iture,
Correct me if I'm wrong, but I don't think it is how the 380 is equipped ?You are of course right! Though I suspect that with the twin PFDs that a similar configuration is available when the correct page(s) is/are selected.

Strangely, the image was part of an Airbus power-point presentation on their revised Stall Recovery Procedure (http://orleans.neting.com.es/esa/ESA_Jazz/Airbus%20Stall%20and%20recovery.ppt).

[Diagnostic]

@Lonewolf_50:
Many thanks for your comments. :) I think it will also be very interesting what the human factors part of the final BEA report says. IMHO sometimes CRM in critical situations works well (e.g. Sioux City UA232), and sometimes it doesn't, like here :(

I'm lucky in my job that I'm often working with engineers who I have worked with before, which makes it easy to build-up knowledge of each other's strengths & weaknesses, and act accordingly to speed-up the process of reaching a common goal. I can only imagine how difficult it is to work on a flight deck, potentially with people you've never (or only rarely) worked with before, and where you could be put into a time-critical troubleshooting situation at any point. :eek:

[CONF iture]

Though I suspect that with the twin PFDs that a similar configuration is available when the correct page(s) is/are selected.
I would seriously doubt that.
It would be, after all this time ... an implicit acknowledgement that sidestick input information is valuable after all, or even worse, could be necessary.

Thanks for the link.
I would rather think that the slide in question must be just an extract from a full video animation.

[DozyWannabe]

It would be, after all this time ... an implicit acknowledgement that sidestick input information is valuable after all, or even worse, could be necessary

Which would be a problem why? Airbus are not the arrogant shysters you seem to think they are - they'd never have put that stall article in their safety journal if they were. The fact is that yes, in some situations some kind of input representation could be useful, but the majority of the time it is not especially so.

To my recollection there has been precisely one non-fatal incident and one accident where it might (stress *might*) have been useful for the PNF to see what the PF was doing with the stick. That's not many bearing in mind we're talking 23 years of FBW Airbus service these days...

I don't see why the "big red button" is coming into the discussion again either - this was not a "what's it doing now?" accident. Indeed the aircraft effectively gave them the BRB effect - giving the pilots full authority plus autotrim in Alternate Law, which at least one of the pilots mishandled. I'm loath to go back to what I was saying several threads ago, because I don't want to induce a hamster wheel effect, but this kind of accident has happened in non-automated aircraft as well - I don't think the FBW had a hand in this case either. Some may disagree, but so far there has been no evidence to support that assertion.

[Lyman]

Yes, I agree, they are not shysters. However, one expects better than one out of two, in Aviation.

[CONF iture]

'shysters' - No. Did I say so ?
'arrogant' - Not wrong. But over confident would be more appropriate.

To my recollection there has been precisely one non-fatal incident and one accident where it might (stress *might*) have been useful for the PNF to see what the PF was doing with the stick. That's not many bearing in mind we're talking 23 years of FBW Airbus service these days...

What are, in your mind, those 2 events ?
Why, in your mind, it *might* have been useful for the PNF to see what the PF was doing with the stick ?

[RR_NDB]

Hi,

FBW is clearly a way to optimize an a/c. (weight reduction, easier to design with redundancy, etc.)

Question for EE and pilots acquainted with Digital FBW a/c:

The problems arise when the machine (a/c) enter some certain states?

E.g.: TAM 3054 overshoot, AF447 first with THS "going" to 13 degrees NU and later presenting erratic SW indications. These planes entered exceptional "states"?

May we consider these planes "entered" strange states difficult to be understood (almost impossible in short time) by crews yet submitted to abnormal and stressful situations?

In non DFBW these "strange states" are rare. The NW 6231 727 (Thiells) Pitot's "memorized pressure due icing" misleading the entire crew. Perhaps we can say the plane entered an "strange state" with it's Pitot's "showing" altitude (instead the speed) to the (astonished) crew.

In summary, my 1st question is:

State machines concept (http://en.wikipedia.org/wiki/Finite-state_machine) may explain several cases where the crew was not able to even understand what was going on?

Observe the issue is not FBW (a good approach) but how we "protect" the plane using "finite States machines". And Airbus SAS pioneered this.

A possible 2nd question is:

Is it possible, by training, prepare the crew to timely understand (the strange states) and act accordingly?

Are we capable to preview the "strange states" the complex machines (full of protections) may enter?

[Lyman]

An excellent, excellent question.

The bottom line here in this entire discussion re: AB fbw, is that it is highly functional in virtually all its iterations when confronted with straight forward challenges to remaining in the air.

If no one else has figured this out, the problem arises, as it does with ALL aircraft, when the monkey grabs the football.

Airbus have this less figured out than other types, and their arrogance in admitting to it is still killing people.

Abnormal situation requires abstract and intuitive action.

NOT ALTERNATE. Bowing to ALTERNATE solutions is killing us.

We don't need ALTERNATE, we need CUSTOMIZED.

And CUSTOMIZATION comes from the cerebellum, not the thirty year old chip, programmed by people who still do not "get" ABNORMAL.

One cannot anticipate that which he has no experience with.

[Zorin_75]

Is it possible, by training, prepare the crew to timely understand (the strange states) and act accordingly?
Nose pointing up, plane going down, blaring stall warning. Very strange state. Maybe they should teach that in flight school.

[Lyman]

I've done that, in flight school. It is an odd regime, and it was shown to me by my instructor. I still remember it. "Hold back stick". WHAT?

Did any of the crew on 447 experience such an attitude? Ever?

As above, To get creative, one needs to have some confidence in a solution, not grab at straws.

To get where you need to be, to save your life, one needs to know where one is.

[RR_NDB]

Hi,

(http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-51.html#post6727280)Abnormal situation requires abstract and intuitive action (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-51.html#post6727280).

With highly capable pilots instead of just "trained operators".

IMO the training requirements are much higher when operating complex machines.

Unless you think (erroneously) everything can be previewed by engineers during design phase.

Perhaps "IT people" influence on Airbus SAS Design approach was excessive.

Many years ago a friend (ex. Air Force one pilot and Safety Board Head) told me: A good pilot must always call his plane by "Sir". With a lot of respect.

An a/c using Finite States Machines in their Systems design approach IMHO requires much more respect. You must be very careful (and respectful) with it.

Their behaviour is never completely understandable. The old "Testability issue" of Complex Systems.

[Lyman]

Testability

The a/c cannot be tested in these places, but her pilots can be....

To stay ahead of one's aircraft requires one must know more than she.

[DozyWannabe]

Perhaps "IT people" influence on Airbus SAS Design approach was excessive.

The "IT People" (actually real-time systems architects and engineers, and among the best in their field at the time) simply implemented a set of specifications from the aeronautical engineers, who themselves consulted with pilots, in exactly the same way that electromechanical engineers have always done in aviation.

Philosophically speaking, the computer specialists only dealt with the "How" - the "What" came from the same people it has always come from.

Airliners have always been complex systems, and have only grown in complexity over time. I suspect very few pilots during the middle decades of the last century knew exactly how the Q-feel system on their Comets and 707s worked, and I'm pretty sure even fewer pilots knew how advanced avionics suites such as those on the Trident and L-1011 worked. The only difference between that generation and the current generation have been how the various systems were implemented, but this will always come up against a seemingly innate human distrust of technology. I wonder how many of BEA's "old guard" took great exception to the (then) new-fangled autoland system, for example.

[Lyman]

The complexity is by and large manufactured of whole cloth. In addition, in dumbing down the threshold of operation, the "complexities" become sequestered in myth, and therefore become unmitigable by tacit agreement; operators will not be trained to them.

No one is better able (potentially) to handle a dynamic situation than the one who is present. To suggest that solutions have already been discerned for every possibility, and Programmed into an airplane, is not only myopic, it has the aroma of Death about it.

Case in Point. "We think Auto Trim UP into a Stall is a solution." On what Planet? Rather than allow that, why was it not aggressively disallowed? Yet in overspeed, the THS is locked in place, when at least arguably, it has a function in correcting PITCH to corral speed.

Independent of training level, how is that desirable?

Explain?

[CONF iture]

Case in Point. "We think Auto Trim UP into a Stall is a solution." On what Planet? Rather than allow that, why was it not aggressively disallowed? Yet in overspeed, the THS is locked in place, when at least arguably, it has a function in correcting PITCH to corral speed.
That’s even worse Lyman, under Normal Law, the system logically thinks it’s time to cancel autotrim by reaching Alpha Prot or slightly above, but when the situation has degraded and Alternate Law is active, the system thinks it’s smart to autotrim all the way whatever the Alpha …

Airbus : If you think you have some doubt about the data you receive, just keep things simple, degrade all the way straight to Direct Law. Make things easier for your crew. Airplanes fly well in Direct Law too ... including yours.

[Cool Guys]

While on the subject of simplicity I would like to butt in if I may.

I can understand how the pilot on AF447 reacted in the way he did. I can’t say that I can explain it but I can understand it. Years ago I pushed the wrong button when my colleague got his fingers caught in a machine. I switched the Run Switch to the “off” position rather than hitting the Emergency Stop button. The Run Switch stopped the machine after its present cycle. The Emergency Stop instantly cut all power. At the point where my colleague got his fingers stuck I had 5 seconds to hit the Emergency Stop to prevent a blade from slicing his fingers off. In the rush I switched the wrong control (I pulled the stick back rather than push it forward). I realised my mistake and I quickly hit the Emergency Stop. Fortunately I reacted fast enough and my colleague still has his fingers.

In the above example I had complete understanding of these controls because I designed them, but I had no practical training on what to do in this circumstance so I did the wrong thing when I needed an instant reaction. However because of my understanding of the controls, and because I had sufficient time, I was able to save the day. Practical training gives you a natural reflex to do something quickly in an emergency situation but understanding gives you the ability to think about the situation and work out what is the right thing to do even if you have not been trained on the procedure. Understanding is gained by theoretical learning and quick response is gained by practical training, actually doing what you should do in real life when a emergency situation occurs.

However these 2 things are related. Training helps understanding and understanding helps training. Sully was not trained on water landings but due to his in depth knowledge he was still able to perform the feat. When learning a complex process you need both. Simplicity is also a factor. After this incident I changed the layout of the front panel including making the Emergency Stop more prominent and simplifying the layout. I simplified the interface. A machine operator or pilot has better things to think about than excessively complex controls. A pilot definitely has many other things to think about. If something is simple it is easier to understand and it is easier to train people on. It is like these 3 things form a triangle. Understanding – Training - Simplicity. You need all 3 sides. If you increase one you naturally increase the other 2. If you reduce one you reduce the other 2. If you make something simpler the person’s understanding will be better and it will be easier to train him. If you make something more complex the person is likely to have a lower understanding and it will be more difficult to train.

A group of semi knowledgeable people generally make things overly complex. One single knowledgeable person can generally make the same thing more simple.
It is easier to make something complex than to make it simple. Unfortunately it is easier to make a complex interface than a simple one.

Obviously an aircraft control system will be a complex system but it should not be made more complex than what it needs to be, and even if someone has done all that is required to get everything totally sussed, surely he would be better off working out how to get laid by his wife than to work out some overly complex interface.

[RR_NDB]

Cool Guys (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-52.html#post6727693)

The rule is here:

KISS principle (http://en.wikipedia.org/wiki/KISS_principle)

And the best phrase, IMO:

"It seems that perfection is reached not when there is nothing left to add, but when there is nothing left to take away"

From Antoine de Saint Exupéry (http://en.wikipedia.org/wiki/Antoine_de_Saint_Exup%C3%A9ry), writer and also an aviator.

[gums]

Just had to get my barb in for Doze, heh heh. And support RR.

The "IT People" (actually real-time systems architects and engineers, and among the best in their field at the time) simply implemented a set of specifications from the aeronautical engineers, who themselves consulted with pilots, in exactly the same way that electromechanical engineers have always done in aviation.

Philosophically speaking, the computer specialists only dealt with the "How" - the "What" came from the same people it has always come from.

Basically, Doze has it right, to a point.

As a systems engineer after I hung up my g-suit, I wrote the specs and the sfwe folks "coded" it. None of the sfwe "engineers" in my company knew squat about aero or mech or actual piloting. No big deal. They were used to dealing in "abstracts" and sfwe design, not a physical system that was to be implemented or simulated in sfwe.

I was their worst nightmare!

I was an aero/EE guy from school, and was a no-kidding pilot with no small amount of experience in various jets. I had also done sfwe work for a few things during my career as a pilot.

I had to explain frame rate requirements due to hysteresis of the mechanical gyro/gimbal platforms and seeker heads of missiles. The old analog systems did the trick via their basic design and had negligible lag as the digital systems had with their frame rates. So we "smooth" the data for control and display. Big deal. But we also had to deal with real world body rates and maybe tgt motion for a weapon and so on. So some functions had to run at very high frame rates while others could lope along at 10 Hz.

enuf background.

As RR says, a finite state machine will react to inputs with very deterministic outputs/actions. That was my company's philosophy for armament control and display systems, and our designs were very easy to validate thru testing. The good news was our systems were easy for the human operators to understand and operate. Our sfwe was not trying to be "intelligent", and "guess" what the human wanted to do.

So I have to throw my lot with the folks that postulate the AF447 crew was presented with conflicting displays and aircraft reactions to their control inputs, and they did not know with certainty what was really happening. Further, their training seemed to emphasize all the FBW protections and the cascade of control law reversions that attempted to retain bank angle limits, pitch angle limits, AoA limits ( read Alpha prot), mach/overspeed warnings, etc. Sheesh!!! Think you would be confused?

Make no mistake, I do not advocate a simple, direct control of the various aero surfaces such as some here believe would save the day. Even the old, old mechanical systems used mechanical/hydraulic components to limit surface deflections and their rates of deflection.

My problem has always been with the "autopilot" type functions and protections that seem inherent in the 'bus FBW design and its reversion modes. For Chrissakes, the jet seems to be extremely stable and docile. Without the autopilot engaged, it should handle just as any large jet. It should also handle well if airspeed/ "q" inputs are lost. But this is where training enters the equation. How does the jet "feel" when most of those "protections" are gone? And worse, what "protections" are still there? So there needs to be a clearly defined reversion sequence that the pilots are trained to deal with, and the more simple, the better, The finite state machine RR and I refer to.

[Zorin_75]

but when the situation has degraded and Alternate Law is active, the system thinks it’s smart to autotrim all the way whatever the Alpha …More precisely, in this state the system thinks it's less smart than the pilot therefore it will do as told without protest.
All these discussions about complex systems are certainly not without merit, but do you think it is a fair assumption this crew would have fared better in a 757?

[rudderrudderrat]

Hi DozyWannabe,
this will always come up against a seemingly innate human distrust of technology
We never distrusted the technology - but were ready to take over when it failed. When it failed and the AP dropped out, the aircraft felt very familiar because it only had the one manual flight Law (Direct).

Why design a series of sub laws which the pilot very rarely experiences or has the opportunity to practice?

[RR_NDB]

In Combinational logic (http://en.wikipedia.org/wiki/Combinational_logic) " the output is a pure function of the present input only". E.g. the (interlock) micro switch on the door of a Cessna prevents flaps activation.

In Sequential logic (http://en.wikipedia.org/wiki/Sequential_logic) the "output depends not only on the present input but also on the history of the input". F-GZCP System "memorized" PF initial NU, maintaining THS at 13deg til the end of the flight.

In TAM 3054 case both pilots didn't understand timely the system output (combinational logic).

Combinational and Sequential logic can help decisively but unfortunately may generate "difficulty to understand" in certain situations specially if you add human factors to the issue.

seemingly innate human distrust of technology (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-52.html#post6727364) Not present among us, you know. Most here are open minded professionals always trying to do the best. Using technology and ALWAYS checking it for a "quality control", in a constant "questioning". Something VERY USEFUL for any Project as an important and necessary feedback.

[Lyman]

"Seeming innate mistrust of technology."

That is a euphemism for "what do you know, my concierge can fly this a/c."

It is out of place here, and harkens to a lay attitude.

Fly by wire is not anything but a new (if thirty years old tech is "new") way to control an aircraft.

It is faster, and generally more responsive and efficient than a human being. It can fly a/c that are unflyable by humans.

Stop. It is also a quick way to the graveyard whilst whistling Dixie if the programming is put together by numpties.

It is a TOOL. A wonderful TOOL. But a TOOL. Those who think it can be operated in fluids without great care are dangerous.

[DozyWannabe]

We never distrusted the technology - but were ready to take over when it failed. When it failed and the AP dropped out, the aircraft felt very familiar because it only had the one manual flight Law (Direct).

I think it was in fact a little more complex than that once you got down into the actual implementation of the design - routing hydraulics, electrical systems and the like. As I said quite a while back, it was only when digital computers started getting involved that the distrust became more vocal, because you had a generation of pilots for whom computers were known as either big number-crunching machines in rooms (which is how they were in real life), or cold, logical machines that frequently went wrong and threatened lives (as they were consistently presented in fiction).

Human psychology is a weird one in that the collective memory can sometimes distort the reality of a situation with cultural perception - this is why I get so mad when people refer to the FCU system as "HAL", because I know that the reality of the former is a million miles from the cultural perception of the latter (which was, after all, a fictitious construct based more on an outgrowth of Asimov's laws as opposed to reflecting any kind of reality). I could go into mind-numbingly dull detail on the subject, but I'll spare you guys that (for now!).

Why design a series of sub laws which the pilot very rarely experiences or has the opportunity to practice?

Firstly, there are only three "Laws" that deal with computer-assisted flight (with the MAN TRIM ONLY fallback when everything is out). Alternate is a single law with variations based on the type of failure the aircraft has suffered (in much the same way as failures of specific systems on older designs meant variations in how to deal with those failures), and all you really need to have at the front of your mind is that if you're outside of Normal Law, you don't have any hard protections - consequently the aircraft must be handled as carefully as if it were conventionally-controlled with no protections. Sustained hauling back on the sidestick outside of Normal Law is therefore as much of a no-no as sustained hauling back on the yoke in a conventional aircraft.

Secondly, pilots *are* supposed to practice them (note PJ2's insistence on practicing all modes in the sim, up to and including MAN TRIM ONLY). ColganAir proved that you don't need an all-singing, all-dancing digital flight control system to lull airline training programmes (and the pilots they produce) into a false sense of security when it comes to stall/upset recovery. Thus we get into a bigger problem that affects the whole industry, whereby many of the MBAs that run the airlines and the accountants that provide the balance sheets do not understand that if you cut training costs, you're shaving the safety margins ever further and increasing the risk that there may be people at the controls who will fumble a recovery in an emergency.

The '90s downturn led to the beancounters shaving the maintenance budgets, which in turn led to an Alaska MD-80 falling into the Pacific, and an FAA crackdown. It seems that in response to that their next move was to shave the training budgets, which is just as dangerous - but the effects are slower to materialise - and it's much tougher to prove that a crash caused by pilot error can be traced back to lackadaisical training than it is to prove a stripped jackscrew was caused by shoddy maintenance.

[Lyman]

Talk about Hamsterwheel.......

[DozyWannabe]

F-GZCP System "memorized" PF initial NU, maintaining THS at 13deg til the end of the flight.

The system (by which I mean the flight controls) only "memorised" it because there was not a consquential opposite command to move it the other way, either from the sidestick or the trim wheel.

In TAM 3054 case both pilots didn't understand timely the system output (combinational logic).

Well, there were procedural complications in that case. The original "reverser inoperative" procedure called for the thrust levers to both be placed in idle and only the engine with the working reverser to be placed into reverse. Airbus discovered several incidents where the lever to the engine with the inoperative reverser was not pulled to idle, extending the landing distance considerably and risking an accident.

As such they came up with a new procedure where both levers were to be pulled all the way through flight idle to reverse on rollout, which made the problem go away, but led to a slight, but noticeable increase in landing distance as the engine thrust on the side with reverser inop would increase, inducing forward thrust on that side.

The TAM crew knew of this latter procedure and indeed used it on the previous leg of the flight, as evidenced by the FDR traces - however the Conghonas runway was short and known to be treacherous, especially in wet conditions. The logical theory is that the very experienced Captain knew of the increased landing distance that the new procedure caused and elected to use the old procedure, ironically, to give him an increased safety margin given the atrocious conditions at Conghonas that night. Unfortunately the crew made the same mistake that had caused that procedure to be revised in the first place and the rest is history.

[Lyman]

The THS kept going due lack of Pilot input. In other words, it autoed into the STALL.

That's called non-cognitive runaway TRIM. Un-commanded in the first place, but requiring a command to stop.

Arse about.

Someone, please define "TRAP".

[Mr Optimistic]

Please stop discussing this: all that needs to be said has been said.

[RR_NDB]

"Our sfwe was not trying to be "intelligent", and "guess" what the human wanted to do."
(http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-52.html#post6727798)

Automation helps but can create very dangerous situations as all of us know. This danger increases when the designers creates “tools” to help the operator introducing a “partner” with high hierarchy. Protections are excellent when designed to preserve limits (e.g. Rudder Travel limiter, etc.) But can generate adverse effects not to mention the “de skilling” potential.

Think you would be confused?

IMO, under stress (normal in many situations) even a designer would be confused.

Make no mistake, I do not advocate a simple, direct control of the various aero surfaces such as some here believe would save the day.

All good Engineers apply confidently WHAT IS NECESSARY to implement a required function. My concern is concentrated in the Top System Engineering approach simply because impacts everything. And cannot be corrected (or tweaked) by SW or even HW fixes.

My problem has always been with the "autopilot" type functions and protections that seem inherent in the 'bus FBW design and its reversion modes.

They are learning and their leadership in this area requires more R&D. My concern is if the commercial success will allow the investment in areas with clear room for improvement, as you mention.

I bring the Finite States Machines because the "partner" introduced to the crew has this structure. Very powerful and increasingly present in our lives. And because they must be well designed and normally requires evolution.

This was not the case in TAM 3054 plane and the other similar cases before.

[5LY]

Bla bla bla! Know an approximate pitch and thrust setting for all flight regimes, and get out the unreliable airspeed checklist. Land, have a beer.

[RR_NDB]

:E:E:E:E

Trimmable Resource Automatically Positioned

:}:}:}:}

PS

The designers made the algorithms. And the a/c' s really (BEA said) worked as designed.

Question:

The crew (under stress) of AF 447 and TAM 3054 did receive ADEQUATE real time indication on the IMPORTANT (auto) configs, respectively of THS (in an stalled a/c) and eng#2 PWR after touch down (landing)?

Observe in both cases i am not even suggesting this as the main cause of the accidents.

i am just commenting the danger of auto (pre programmed) functions that apparently don't respect how rich is reality faced by us. And the potentiality (risks) of complex systems to perform as K.I.C.S. mechanisms. Just the opposite intended by the designers.

C. stand for Complex

[DozyWannabe]

Please stop discussing this: all that needs to be said has been said.

That would depend what you mean by "this" - after all, you yourself were advocating the old "big red button" argument a short time ago, which would arguably have had no effect on this incident at all.

Trimmable Resource Automatically Positioned

Depends on your definition of "Automatic" - it moved because the PF commanded it to move. If he wasn't aware that he was commanding it to move, then that was a fault in his training - not the aircraft, for which plenty of documentation on the functions of autotrim in both Normal and Alternate Law is available even to non-pilots.

The designers made the algorithms. And the a/c' s really (BEA said) worked as designed.

The control laws were designed by the systems engineers rather than the software engineers as a way to abstract the complex operations involved to a more easily-understandable level to non-techies.

The crew (under stress) of AF 447 and TAM 3054 did receive ADEQUATE real time indication on the IMPORTANT (auto) configs, respectively of THS (in an stalled a/c) and eng#2 PWR after touch down (landing)?

Of course - in the case of the trim wheel position indicator in the case of the former and engine power indicators in the case of the latter. The problem is that no-one appeared to have been looking at those indications - understandable in a stress situation, but in this case the design of those systems was no more or less complex than in any other modern aircraft. The trim wheels are in the same place on every other equivalent airliner, as are the engine indications. In the case of the TAM accident, even the old moving thrust lever argument can't be brought up, because whether they move or not the fact is that one of them was clearly in the wrong position. Unfortunately it would appear that neither pilot noticed, presumably because they were (understandably) fixated on speed indications and trying not to run off the end of the runway. This was also cemented when the Turkish crew did not notice the moving thrust levers of their 737 pulling off power.

i am just commenting the danger of auto (pre programmed) functions that apparently don't respect how rich is reality faced by us. And the potentiality (risks) of complex systems to perform as K.I.C.S. mechanisms. Just the opposite intended by the designers.

C. stand for Complex

In the case of AF447, the only automatic function involved was the trim, and that was wholly slaved to the inputs of the flight crew on the sidestick as soon as Alternate Law was latched - at the risk of repeating myself, If [the PF] wasn't aware that he was commanding it to move, then that was a fault in his training - not the aircraft, for which plenty of documentation on the functions of autotrim in both Normal and Alternate Law is available even to non-pilots..

In the case of TAM, if you only move one thrust lever to idle on a conventional aircraft, the engine controlled by the other thrust lever will continue to produce power just the same as it did in that case. It was likely there was no "confusion" on the part of the crew as to why they were using the old and deprecated method - because at least one of them knew that it stopped the aircraft faster. It was just unfortunate that in adopting that method that they made the same mistake that caused the old method to be deprecated in the first place.

I don't think systems complexity had a great deal to do with either case, notwithstanding the fact that there is no such thing as a "simple" system to control a modern airliner.

[gums]

No problem here with HAL until HAL starts to get in the way of what we pilots believe, actually BELIEVE, what we need to do and HAL gets in the way because HAL is programmed to PROTECT us. 'nuf there, so on....

INSERT: Alaska airlines THS accident not relevant here, as it was a clear mechanical problem and the crew tried everything in the book and some neat techniques until all was lost..

The 'bus reversion sequence appears to preserve many "autopilot" functions until all else turns to worms ( old fighter pilot phrase, so excuse me). Fer chrissakes, the jet seems to be very docile and has inherent spin resistance and such. There should only be two "laws" - autopilot and manual. The Otto limits could also be the "manual" ones, but the pilot inputs would be from the pilots and not some confuser. So retain the overspeed and AoA warnings. Let the pilots fly as they wish, but don't allow HAL to keep trying to "protect" them.

Problem with the 'bus is after A/P disconnects for whatever reason the pilot may think he/she has the "protections" that existed just a second before. Not so. The "autotrim" function still is active, and the alpha prot feature can be confused or even disabled when HAL decides that air data is unreliable.

What the pilots need is something to hang their hats on when the autopilot functions and all the layers of "protections" are invalid.

To Doze:

Many of the sfwe-illiterate pilots, and even anti-sfwe folks can provide bad inputs to the sfwe folks. I have some great war stories about the shuttle folks when NASA implemented the HUD for that beast. My roomie helped get the one you all saw a few months ago on its last landing.

As a systems engineer that wrote the spec for the sfwe folks to implement I always explained our rationale. I was open to tweaks and helpful features. But I basically used the state machine concept that RR has crowed about. And I am a disciple of the finite state machine for many implementations, especially those involving nuclear weapons and flight control systems.

We can discuss this issue privately, or we can create a new thread.

[DozyWannabe]

No problem here with HAL until HAL starts to get in the way of what we pilots believe, actually BELIEVE, what we need to do and HAL gets in the way because HAL is programmed to PROTECT us. 'nuf there, so on....

The problem there is that in the vast majority of cases, the FCU (or as you insist on calling it, "HAL") is right. In any case you have to be doing some pretty unusual maneouvres for an airliner before any of the hard protections kick in (namely continuing to demand bank angles past 67 degrees, letting the AoA increase until approach to stall or increasing thrust or downward pitch at the overspeed limit).

INSERT: Alaska airlines THS accident not relevant here, as it was a clear mechanical problem and the crew tried everything in the book and some neat techniques until all was lost..

I wasn't saying the incidents were similar, I was using it to illustrate the different tactics the higher-ups were using to reduce costs - cutting maintenance in the '90s, and training when the FAA closed the door on dodgy maintenance practices.

The 'bus reversion sequence appears to preserve many "autopilot" functions until all else turns to worms ( old fighter pilot phrase, so excuse me). Fer chrissakes, the jet seems to be very docile and has inherent spin resistance and such. There should only be two "laws" - autopilot and manual. The Otto limits could also be the "manual" ones, but the pilot inputs would be from the pilots and not some confuser. So retain the overspeed and AoA warnings. Let the pilots fly as they wish, but don't allow HAL to keep trying to "protect" them.

You're getting autopilot functions and limits confused with FCU protections - for a start, traditional autopilot limits are set considerably more stringently than the FCU protections will allow (as far as I'm aware there's no autopilot in the world that will allow 67 degrees of bank, for example). FCU protections can also command the engines to increase thrust in the case of stall protection whether FMC (A/P) is engaged or not, which is one of the reasons why they are called "protections" rather than "limits" (I believe you asked that question earlier on?).

With all due respect, I find "confuser" as infuriating as "HAL". If I started using derogatory terms for pilots in the same manner I'd be banned before too long. I go out of my way to show respect to the pro flyers on here, and I don't think it's unfair to request a bit of common courtesy in return.

Problem with the 'bus is after A/P disconnects for whatever reason the pilot may think he/she has the "protections" that existed just a second before. Not so. The "autotrim" function still is active, and the alpha prot feature can be confused or even disabled when HAL decides that air data is unreliable.

If the A/P disconnects in almost all cases, the pilot *will* still have the protections - the protections are lost in a UAS situation when Alternate Law is triggered and latched. The protections in Alternate Law are soft protections that consist of warnings and attempts to return to S&L - unless they are overridden by pilot inputs as they appear to have been in this case.

What the pilots need is something to hang their hats on when the autopilot functions and all the layers of "protections" are invalid.

And they have it - you can't blame the systems for the apparent response of the PF, which would be wildly inappropriate in any airliner.

Many of the sfwe-illiterate pilots, and even anti-sfwe folks can provide bad inputs to the sfwe folks. I have some great war stories about the shuttle folks when NASA implemented the HUD for that beast. My roomie helped get the one you all saw a few months ago on its last landing.

Would be interested in hearing them, but I don't see where that applies here - this is not a case of the Airbus control logic being a specific example of a complex system confusing the pilots, this is a case of a really nasty overwhelming situation getting on top of a crew who were not prepared to deal with it by their trainers and empoyers, just as it was with the Stony Point 727, the BirgenAir 757 and the ColganAir Q400.

We can discuss this issue privately, or we can create a new thread.

Maybe another time, as I've got a lot on at the minute and can't follow this as much as I'd like to. :)

[infrequentflyer789]

More precisely, in this state the system thinks it's less smart than the pilot therefore it will do as told without protest.


Sorry, but if you are going to claim to be precise - the system doesn't think anything at all.

Some people here seem to be ascribing far more complexity and "intelligence" to the aircraft systems than is actually present.

This is leading them into the trap of blaming the designers for not considering rule A (do not trim up if AOA >X, Alt = Y, airspeed = Z) which apparently is perfectly obvious (with hindsight from an armchair - 3 real pilots on the night didn't find it obvious...). Thinking the designers screwed up because the system is too complex, they demand it be made simpler, not realising that it is already far simpler than they realise, and far too simple to implement the rules they've asked for.


The autotrim simply moves THS, limited by stops, to unload the elevator - with a bit of hysteresis thrown in (probably thresholds on elevator displacements and time).

The pilots may stop / override autotrim, and other systems on the plane may stop autotrim. Various protections may stop (or limit) the autotrim, and the higher level mode/law state may switch those protections on or off, or switch off autotrim itself (off in direct law).

Autotrim did what the pilots asked simply because that is what it does, and nothing told it to stop. It didn't look at the pilot input and the AOA and the current law/state and decide it oughtto move because law=alt even though AOA > stalled.

[infrequentflyer789]

The THS kept going due lack of Pilot input. In other words, it autoed into the STALL.

That's called non-cognitive runaway TRIM. Un-commanded in the first place, but requiring a command to stop.

Arse about.

Someone, please define "TRAP".

THS responded to pilot up-elevator input. Nothing more nothing less and nothing uncommanded. Down-elevator would have undone it - but the elevators were never put down after the stall.

THS didn't auto into the stall either. Look at the traces. Stall was achieved with elevator alone.

Inadvertently stall a big jet and you've already got a big chance of dying (odds are bad enough even in GA). Do it with no outside visual reference, some already broken instruments and in turbulence in middle of a cb... and your chances are probably <10% at best (at an optimistic guess). By the time the THS started moving, they were already well into a trap and needing a miracle.

[DozyWannabe]

Some people here seem to be ascribing far more complexity and "intelligence" to the aircraft systems than is actually present.

You win the last couple of pages of this thread.

Our sfwe was not trying to be "intelligent", and "guess" what the human wanted to do.

I missed this statement earlier, but when I did see it I wondered where otherwise intelligent and logical people get their information. The FCU does neither of these things. Under manual control and in Normal Law it simply responds to commands - the only time protections come into play is when what is being commanded exceeds the pre-programmed design limits of the aircraft, in which case it will respond to every command that would not exceed that limit. No "intelligence" beyond a set of pre-programmed responses, no "guessing".

Further, their training seemed to emphasize all the FBW protections and the cascade of control law reversions that attempted to retain bank angle limits, pitch angle limits, AoA limits ( read Alpha prot), mach/overspeed warnings, etc. Sheesh!!! Think you would be confused?

Quite where gums gets his information on AF training procedures I am not sure, but he sounds awfully certain.

[infrequentflyer789]

Airbus : If you think you have some doubt about the data you receive, just keep things simple, degrade all the way straight to Direct Law. Make things easier for your crew. Airplanes fly well in Direct Law too ... including yours.

Not if the pilot doesn't trim - see Perpignan. Doesn't work too well on other planes either - Bournemouth, Schipol...

Common factor - suprise auto dropout. Let's hit the pilot with stall warning and at the same time disconnect the biggest pitch control surface from the stick, so the pilot needs two controls for pitch where a moment ago it was just one...

Is that really the best user interface ?

[CONF iture]

Is that really the best user interface ?
Best user interface must be the simple one.

Auto trim under Auto pilot
But Manual trim under Manual flight

No ambiguity on who has to trim.
If the pilot quits trimming when he should not … then he might have to pay the price but let’s not pretend to build the perfect aircraft that will solve all.

As a pilot I need a simple tool I can understand and trust.
Don’t make it more clever than necessary.
Train me properly on it.

[gums]

Thank you, Conf.

When I read the 'bus "manuals" and such that we have had provided here, I see a plethora of reversion "laws" that are not really "laws". They are simply less restrictions on bank angle, pitch attitude, a few AoA functions and associated "warning" chimes or whatever, and the beat goes on.

My main point is that the pilots need both understanding of the system and the flying/handling characteristics of the jet when they aren't sitting there "managing" systems. So Conf's statement rings home to this old pilot. Some of us are not anti-computer or anti-FBW or anti-anything. We just need to know when we have control or HAL is getting in the way.

The "basic" control laws of the 'bus must be made clear, and there just seems to me that those basic laws are not well-known amongst the crews, and the warnings and advisory stuff does not reflect the actual aero condition of the jet when it loses a sensor or two.

BTW, I use the term "HAL" because it implies some artificial intelligence on the part of the basic FBW system design I have seen in the 'bus manuals we have had linked to here. And I don't like it.

There are "limits" and "protections" but I am not sure that the system clearly distinguishes which is which as far as the pilot understands.

I still maintain that too many "limits" are embedded in the reversion sequences that are not necessary for safely flying the jet when we have such a simple failure as pitot-static system problems. We don't need a direct control of the elevator or ailerons/spoilers as if we were flying a P-51 70 years ago. I see too many "protections" embedded in the control laws of the 'bus that are not necessary for basic flying the jet, and they can cause confusion for the pilots when sierra happens.

I am not sure that all the 'bus "limits" were specified by pilots. My gut feeling is that the FBW design offered an opportunity to do "neat" things, and the sfwe folks went with a few suggestions. The emphasis upon auto-everything except putting on the brakes after touchdown and steering the jet to the ramp bothers me.

[DozyWannabe]

My gut feeling is that the FBW design offered an opportunity to do "neat" things, and the sfwe folks went with a few suggestions. The emphasis upon auto-everything except putting on the brakes after touchdown and steering the jet to the ramp bothers me.

Well, based on what I was told by the people who were there, you're dead wrong. Don't let your experiences with a weapons outfit in the US make judgements for you on how a pan-European civil airliner project went down.

Also, CONF is a long-time hater of everything the 'bus stands for, so of course he's going to say that. To clarify for CONF, here's the supposedly "ambiguous" list of trim auto/manual status:

Normal : Auto
Alternate : Auto
Direct : Manual

RR_NDB claims that the Airbus system is an example of "Top [Down] Engineering", whereas in fact I was told it was a classic example of Top-Down specification with Bottom-Up implementation - meeting in the middle, which a lot of engineers claim is the most effective way to do things. The whole idea behind the "Laws" was to present a relatively easy set of mnemonics for pilots to understand the aircraft status - as such the A320 was the first airliner to attempt to address the problem of a non-normal situation increasing workload on the pilots in a 2-crew flight deck.

In the days of 3-crew operation, the Flight Engineer was expected to know the systems intimately, along with all the failure mode combinations and settings to maintain safe flight when those failures occurred. The only reason Alternate Law has sub-modes is because that knowledge of the systems is coded into the FCU logic - I'll say it again here - all a pilot really has to remember about Alternate Law is that there are no hard protections and that more care has to be taken to ensure flight envelope limits are not exceeded. If that's too complicated for the average pilot to understand, it's a wonder any pilot ever passed their IR*.

The implementation was "Bottom-Up" in the sense that Direct Law is the first layer of abstraction, providing straightforward control of the surfaces via digital means. Alternate was the next layer, roughly analogous to the old A300/A310 protections which activated only when the pilots let go of the controls. Normal was the third and final layer, which added the advanced FCU protections that made the Airbus FBW series seem like such an advance - when it was in fact only an iterative improvement over the previous generation.

Even the supposedly more "pilot-centred" B777 has more than just "manual" and "autopilot" modes, and again as I've said before, the force-feedback logic is itself far more complicated under the hood than anything in any of the A320's systems.

[* - Note to those for whom English is a second language - what I'm actually saying here is that I don't believe that the average pilot would find the flight control law system on the Airbus FBW series too complex to understand.]

[jcjeant]

Hi,

Always interesting to visit the BEA site
The last communication at 30 September : (in french)
http://bea.aero/fr/enquetes/vol.af.447/com.30.septembre.2011.fr.pdf

Le BEA constate que de façon récurrente des documents de travail relatifs à des
enquêtes de sécurité en cours contenant des informations non validées,
couvertes par le secret professionnel, sont divulgués auprès des media, à des fins
autres que l’enquête de sécurité.

C’est pourquoi, le BEA rappelle aux acteurs concernés que :

- le seul objet de ces enquêtes de sécurité est d’établir les circonstances précises
et de déterminer les causes de l’accident ou de l’incident et d’en tirer des
enseignements de sécurité ;

- l’enquête de sécurité nécessite un travail long et rigoureux conclu par la
publication d’un rapport final.

Les affirmations partielles, erronées et sorties de leur contexte rapportées aux
journalistes, tant que l’enquête n’est pas terminée, donnent lieu à des
interprétations et spéculations, qui ne peuvent que troubler le public et engendrer
la polémique entre les acteurs concernés.

Le BEA rappelle qu’il est le seul habilité à donner des informations sur une
enquête qu’il a ouverte à la suite d’un accident ou d’un incident.The BEA notes that repeatedly working papers relating to
safety investigation with information being uncommitted,
covered by professional secrecy are disclosed to the media, for
other than safety investigation.

Therefore, BEA reminded stakeholders that:

- The only purpose of the safety investigation is to establish the precise circumstances
and to determine the cause of the accident or incident and to draw
safety lessons;

- The security screening requires a long and rigorous concluded by the
publication of a final report.

The claims partial, inaccurate and out of context to reported
journalists, until the investigation is not over, give rise to
interpretations and speculations, which can only confuse the public and lead
the controversy between the parties concerned.

The BEA said that he is the sole authority to provide information on a
investigation it has opened following an accident or incident.The BEA said that he is the sole authority to provide information on a
investigation it has opened following an accident or incident
It seems presumptuous ....
Or maybe it is a warning to employees of BEA (from which the majority of leaks come)
The BEA notes that repeatedly working papers relating to
safety investigation with information being uncommitted,
covered by professional secrecy are disclosed to the media, for
other than safety investigation.


BEA read Pprune .. ? or this .. ?
AF447 « AF447 (http://status07.blog.lemonde.fr/category/af447/)

[GerardC]

Originally posted by gums :
The emphasis upon auto-everything except putting on the brakes after touchdown and steering the jet to the ramp bothers me.You are wrong "putting on the brakes after T/D" IS "automatic".
They even invented a "brake to vacate" gadget on the A 380 to "program" the runway exit point after touch down.

[Lyman]

infrequentflyer789

You're not wrong, and I know what you're saying. For the moment, consider that the Pilot flying after a/p loss was working his theory "I think we have some crazy speed.."

Repeating how the aircraft behaves with its trim doesn't help an understanding.

From the releases and FDR data, we believe the a/c was NOT oversped, and all the UP elevator was the pilot's.

He made a mistake. A mistake he appears to have held on to for the rest of the flight. We know this because at the very last, when the Captain tells him "Climb", he says "But I have held back stick for some time."

You want to go straight to "What Morons"? Feel free, but the a/c is part of the crash, and how she gets along with her crew is (seems) to be the cause of this crash.

More important is what caused the PF to believe the a/c was fast. Guessing won't do, and chiding a dead man solves nothing.

FYI. The 54 seconds of STALL annunciation comes from the DFDR. Call me old fashioned, but until I hear it on the CVR I consider the jury to be OUT.
No offense, but proof is needed.

We know that the a/c recovers from STALL with elevators DOWN and full UP THS. So if the elevators are effective, why did someone decide that on the way up, Trim was necessary? And should be Auto?

[CONF iture]

Also, CONF is a long-time hater of everything the 'bus stands for, so of course he's going to say that.
Dozy,
Behave your comments please.
Or is it supposed to be the ultimate argument when things don’t go your way ?

Working on the Airbus is my job, maybe I have some credential to appreciate what could be better on it.
Do not take it too personal if critics are formulated towards Airbus.

To clarify for CONF, here's the supposedly "ambiguous" list of trim auto/manual status:
Normal : Auto
Alternate : Auto
Direct : Manual
What does it clarify on behalf of AP or Manual flying ?
Put as many laws as you like but leave to the pilot to trim when he’s manually flying.

[DozyWannabe]

What does it clarify on behalf of AP or Manual flying ?

It's the same for both! Though if I recall correctly autoflight is inhibited in Direct Law.

Put as many laws as you like but leave to the pilot to trim when he’s manually flying.

Why?

[jcjeant]

Hi,

DW
Why?Because
CONF
manuallyLogic .. no ?

[CONF iture]

Why?
Why not Doze ?

[DozyWannabe]

Because it adds extra workload, requires ambidextrous manipulation of controls and undermines the concept of the systems design in the first place. If a majority of Airbus pilots shared your view then it might be worth revisiting, but as that seems to not be the case - for all my opinion's worth - I don't think it is.

[rudderrudderrat]

Hi DozyWannabe,

The first two reasons you quote would make every conventional aircraft impossibly difficult to fly.
The real reason is as Tyropicard pointed out a long while back - How would you know when and in which direction to trim, if you are in Normal or Alternate Law?"

[CONF iture]

Because it adds extra workload, requires ambidextrous manipulation of controls
Sorry, I almost forgot you actually don't have practical experience of piloting.
Better understand now why guys on Boeing and every other brands must be more qualified ...

[DozyWannabe]

The first two reasons you quote would make every conventional aircraft impossibly difficult to fly.

Not at all - it's just that autotrim can help take the load off and give you hands on throttle and stick if necessary.

The real reason is as Tyropicard pointed out a long while back - How would you know when and in which direction to trim, if you are in Normal or Alternate Law?"

Same way as in a conventional aircraft, by looking at the trim wheel indicators.

Sorry, I almost forgot you actually don't have practical experience of piloting.

Airliners no, but I've done some single-engined prop flying in my youth.

Better understand now why guys on Boeing and every other brands must be more qualified ...

How does that work? Just because autotrim is present doesn't mean that pilots should not be trained how to trim manually - as I've said from the start, if airlines want to use the automatics so much that manual flying skills are eroded, then they must beef up their manual training programmes to compensate.

[CONF iture]

Airliners no, but I've done some single-engined prop flying in my youth.
Then time to practice again maybe ... just to remind how you don't need to "look at the trim wheel indicator" to actually trim.

[DozyWannabe]

I know you don't *need* to, but it's one way to quickly verify what your trim settings actually are. This isn't the place for another go on the "tactile feedback" hamsterwheel.

[Machinbird]

Dozy
What ran the trim up at the stall was the Airbus trying to effectively hold an attitude and being unable to do so without adding more THS trim.

Who really knows why the PF decided the nose needed to be 15 degrees up, but the aircraft was trying to make it happen.

If the nose had not been prolonged up by the addition of THS trim, it would have fallen through at the stall like most other aircraft.
In Normal law, additional nose up trim is disabled by angle of attack protection:
When angle of attack protection is active, THS is limited between setting at entry in
protection and 2° nose down (i.e. further nose up trim cannot be applied).
Similarly when the load factor is higher than 1.3 g, or when the bank angle gets outside
± 33°, the THS is limited between the actual setting and 2° nose down.

In Alternate law, it appears that all use of AOA is discarded. No doubt the engineers had their reasons, but I would be real interested in knowing what they were.
Instead, in Alt 1, you have Low Speed Stability which is derived from Airspeed indications:

Low speed stability

At low speed, a nose down demand is introduced in reference to IAS, instead of angle of
attack, and alternate law changes to direct law.
It is available, whatever the slats/flaps configuration, and it is active from about 5 knots up
to about 10 knots above the stall warning speed, depending on the aircraft's weight and
slats/flaps configuration.
A gentle progressive nose down signal is introduced, which tends to keep the speed from
falling below these values. The pilot can override this demand.
Bank angle compensation is provided.
In addition, audio stall warning (crickets + "STALL" synthetic voice message) is activated
at an appropriate margin from the stall condition.
The PFD speed scale is modified to show a black/red barber pole below the stall warning.
Va prot and Va max are replaced by Vsw (stall warning speed).
The a floor protection is inoperative.


In Alt 2, you have:

PROTECTIONS

Identical to protections in ALT 1, except that :
1. There is no bank angle protection in ALT 2 law.
R 2. In case of failure of 2 ADRs, there is no low speed stability.


On AF447, two of the 3 AOA sensors were functioning properly and 1 was lagging. The flight control logic was to disregard the outlier, so valid AOA data should have been available.
If the engineers had not decided to discard use of AOA in Alternate Law, AF447 might have been just a flight that scared the passengers a bit but no long term harm done. I will bet they are revisiting those decisions at the present date.

[DozyWannabe]

Dozy
What ran the trim up at the stall was the Airbus trying to effectively hold an attitude and being unable to do so without adding more THS trim.

Who really knows why the PF decided the nose needed to be 15 degrees up, but the aircraft was trying to make it happen.

It "tried" to hold that attitude because that was the attitude commanded and *held*. You can't have it both ways - heaven knows the FBW Airbus has come in for some stick for "limiting" pilot input - in this case it was doing exactly as it was told, as would any other aircraft.

In Alternate law, it appears that all use of AOA is discarded. No doubt the engineers had their reasons, but I would be real interested in knowing what they were.

Because Alternate Law is by definition a degraded systems status. Any and all stability protection in Alternate is "soft" and as such can be overridden by pilot input, because the design assumes that the pilot knows more than the systems at that point. Even if AoA protection was operative in Alternate Law, the PF's inputs continued to demand nose-up for the majority of the way down and would have overridden it.

The rules in a crisis situation are Aviate, Navigate, Communicate in that order, and whether through poor training or otherwise, this crew sadly failed at the first hurdle. Regardless of the THS angle, all that needed to happen was for one of them to push the nose down in response to the Stall Warning alarm that was going off for nearly a minute and the result would have been a scary ride for the passengers and coffee without croissants for the flight crew after landing in Paris.

[infrequentflyer789]

If the nose had not been prolonged up by the addition of THS trim, it would have fallen through at the stall like most other aircraft.


Do we know that it's THS or just speculate ?

I don't think the trim goes up much until well into the stall - and by the time it reaches max NU, AOA is already well over 30deg.

What is clear (to me) is that any C* law aircraft will respond to any nose-down stall break with control inputs to counter it - and therefore the pilot may never see the break. I think C*u (i.e. 777) will do the same, but not entirely sure what influence the speed term will have. Once upon a time I might have known how to work it out...

It will, however, respond to the break with elevators, not THS - which will follow slowly on the bus.

Looking at the report, at around 2.11.00, AOA around 10deg, pitch starts to vary and elevator - but sidestick input is all over too, so not clear as to cause/effect. I think they are stalled there though. About 45secs later, elevators and THS hit the stops and suddenly theres a big downward pitch. The stall break finally wins ?


Or, short form, you're right, but it's elevator and THS that stop it - not THS alone.


In Normal law, additional nose up trim is disabled by angle of attack protection:
In Alternate law, it appears that all use of AOA is discarded. No doubt the engineers had their reasons, but I would be real interested in knowing what they were.


I don't know but I have some thoughts / speculation. For another post, no time right now.

[Machinbird]

infrequentflyer
Do we know that it's THS or just speculate ?


It is simply logical considering the mechanics of the situation. The aircraft in pitch is effectively bar on a pivot (a seesaw if you will). The THS additional incidence had the effect of applying additional downforce on the tail. Without that additional downforce, the elevator by itself would have met its match long before and the nose would have fallen.

You can see a pitch oscillation as the aircraft begins to stall with PF actively countering and the THS angle continually increasing.

When the THS trim could go no higher, PF's strategy changed from some nose up, some nose down to steady nose up-he was trying to make up for the additional THS trim angle he no longer was receiving.

Dozy

...in this case it was doing exactly as it was told, as would any other aircraft.

Conventional airplanes recognize aerodyamic reality and drop their nose in the stall (assuming they are not T-tails)
FBW aircraft continue to follow their instructions and in the case of the A330 can grab additional resources (THS nose up trim) that no sensible pilot would apply in a stall.


Because Alternate Law is by definition a degraded systems status. Any and all stability protection in Alternate is "soft" and as such can be overridden by pilot input, because the design assumes that the pilot knows more than the systems at that point.

Sounds to me that they threw out the baby with the bathwater. If AOA had stopped the THS trim at 3 degrees or so, AF447 would have likely begun to bob up and down like a Cherokee or Cessna 150. Don't you think one of the guys in the front office would have gained a clue?

The one problem with AOA is that the A330 AOA envelope reduces at higher Mach.
http://home.comcast.net/~shademaker/MachVsAOA.jpg
Probably all they needed to do was use the Mach at dual ADR loss for setting autotrim upper limits as in Normal law. If you really needed more trim later, you could do it manually.
Regardless of the THS angle, all that needed to happen was for one of them to push the nose down in response to the Stall Warning alarm that was going off for nearly a minute and the result would have been a scary ride for the passengers and coffee without croissants for the flight crew after landing in Paris.
Dozy, I wasn't there to see what they were up against nor were you, but it is one thing to put a foot through the bars of the tiger's cage and another thing entirely to open the door and walk in. If the trim had stopped earlier, the probability of successful outcome would be much higher.

[airtren]

It "tried" to hold that attitude because that was the attitude commanded and *held*....

What ran the trim up at the stall was the Airbus trying to ....



No Dozywannabe. The PF acted on the elevators, not THS. If the PF acted on the THS, that would have been Manual THS Control.

It was an algorithm in the FBW system that decided to move the THS to max UP position, during the exact period of time in which the STALL WARNING was ON, in spite of the elementary rule, which now is recognized straight forward by Airbus that the STALL is an AOA issue, which is addressed by reducing the AOA.

The algorithm used at the time of the AF 447 accident is incorrect; it has contributed to the Stall. Airbus has recognized the need for corrections.
.....

There is also another thing you may want to come to terms and recognize. It is the importance of a "direct information transfer" between the PF and PNF regarding the position, and actions on the side stick.
,
Perhaps there is a need for a call onto the computer/software expertise, which you've mentioned on a number of occasions, which should be of help in recognizing the qualitative difference between "direct" and "indirect" "information transfer".

[Old Carthusian]

Gentlemen
The debate about trim, types of laws etc and whether the aircraft has an influence on the accident is sterile and irrelevant. The simple principle here is 'Know your machine'. It doesn't matter what the aircraft does or how it behaves if you know what the machine does. This is the question that everyone should be focusing on - why didn't the pilots know their machine and it isn't a problem with the machine.

[Lyman]

Also, well before the THS acted UP automatically, the Stall would have occurred if the a/c had not been moderated by g prot. G protection (limit to 1.65+) allowed the a/c to Pitch up longer, delaying the STALL and Nose Drop. With STALL earlier, and at higher velocity, the PF would have experienced the Drop, and could have acted accordingly. As it was, the a/c STALLED later, slower,because it was "Protected" from attitudes that would have caused the STALL to be pedestrian, rather than exotic.

[Machinbird]

OC
why didn't the pilots know their machine and it isn't a problem with the machine
OC, There are several levels of knowing your machine. Because I was mechanically inclined, I got into the maintenance manuals and knew my machines better than most, but that was not a 100% guarantee that I knew what these aircraft were doing at every single moment.

Since then, the level of complexity of aircraft has gone up by an order of magnitude or two. I remember a number of years ago that Boeing and the airlines decided that it wasn't practical to teach aircrews everything about their aircraft and to only teach procedures (About the time that the 747 first came out as I recall). With computerized aircraft and pages and pages of logic diagrams, you will run out of time before you really understand how your aircraft works.

Now take an aircrew that knows their procedures pretty well, put them several hours into a routine flight, then suddenly pull the props out from under them in the wee hours of the night in turbulence. Before they can even begin applying procedures, they need to understand what they are facing. If they begin poorly, they can make seriious mistakes. Do we really need to pull all the props out?

[Lyman]

Pulling all the props (prots) out is exactly what should have occurred. That is the manual a/c being proposed under these conditions. can't have it both ways. Having it every which way or trying to, is what caused the crash, if one is dependent on the mode (decision) loop explanation.

[RR_NDB]

airtren: It was an algorithm in the FBW system that decided to move the THS to max UP position, during the exact period of time in which the STALL WARNING was ON, in spite of the elementary rule, which now is recognized straight forward by Airbus that the STALL is an AOA issue, which is addressed by reducing the AOA.

The algorithm used at the time of the AF 447 accident is incorrect; it has contributed to the Stall. Airbus has recognized the need for corrections. (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-54.html#post6730630)
.....

When facing important failures (design flawns, algorithms, etc.) you must be able to aviate and "accomplish your mission". A pilot MUST know how to, INDEPENDENTLY of the degree of TYPICAL degradation in the a/c.

(Typical: The Probable and even the Possible in practical terms)

The best way is to deliver (after the degradation) to the crew a basic machine which they (MUST) know VERY WELL in order to "complete the mission".

The "graceful degradation feature" of the a/c never could create complex scenarios difficult or impossible to be "solved" in time by the crew.

And to allow the crew to aviate, the design (law reversion, human machine interface, etc.) must be "State of the art". To allow a "basic" simple operation. A K.I.S.S. one. When mostly needed.

Obs. Obviously, i am not speaking about maintenance related failures or other "external" degradation factors.

DozyWannabe, I will answer ASAP important considerations of your recent posts.

Just a preliminary remark: Obviously the "mechanisms" involved in a modern airliner are growing in complexity. When i mention the K.I.S.S. concept i am not speaking about what is inevitable. Einstein put this very clear. There is a threshold.

[Old Carthusian]

It is precisely a matter of knowing your machine, nothing more and nothing less. Knowing what it does, knowing what happens if the various flight states are in operation. It's really a simple thing - it's called professionalism. If the machine is complex then one needs to be able to work on a different level but one needs to prepare. It's called flying and it seems it isn't encouraged these days. But the aircraft is not responsible for this - the computer systems aren't responsible for this, the manufacturer isn't responsible for this. The airline is. Isn't it time to stop chasing after red herrings? The accident is the responsibility of the pilots flying and the airline which put them in the situation. It is not due to the complexity of the machine or even the interface but a failure in procedures, training, psychology and CRM. Human factors, gentlemen - focus on these.

[mm43]

Originally posted by Old Carthusian ...

It is not due to the complexity of the machine or even the interface but a failure in procedures, training, psychology and CRM. Human factors, gentlemen - focus on these.Thank you! I have absolutely no doubt that you are right.

The aircraft was never involved in teaching its masters - it was the other way. Its masters were 'meant to know' the aircraft's limitations.

[MaxJack]

I have followed this thread since it started, and have tried to understand all technical terms, but I have a simple question, and, is there a simple answer?
If in a completed stall, at FL35-38, and then ”falling”. Could you recover, and if yes, how do you recover from the stall during the fall?
According to the Airbus Stall and Recovery Procedure, thrust is not an option, but could rudder settings bring it back again? And how then?
Or is there no way out, as in this case.

[infrequentflyer789]

Also, well before the THS acted UP automatically, the Stall would have occurred if the a/c had not been moderated by g prot. G protection (limit to 1.65+) allowed the a/c to Pitch up longer, delaying the STALL

G isn't anywhere near 1.65 apart from at the beginning of the climb - look at the traces.
If G limits kicked in, it wasn't in the stall.

[AlphaZuluRomeo]

If in a completed stall, at FL35-38, and then ”falling”. Could you recover, and if yes, how do you recover from the stall during the fall?
Push the stick, thrust idle => dive.
Trade height for speed, while reducing AoA.
Then recover from the dive.

Why the rudder? Best to keep your aircraft symetrical, a spin is worse than a stall ;)

---------

About the THS & difference in normal/alternate law: we already discussed that some months ago.

[rudderrudderrat]

G isn't anywhere near 1.65 apart from at the beginning of the climb Correct. That's why the stab trim was allowed to continue trimming.
In Alt Law, with side stick free - the FBW computers will continue to move the elevators whilst attempting to hold the attitude whilst the speed washes off.
In ALT2, the auto stab trim continues despite exceeding Alpha Prot / Max.
The natural nose drop at the stall is masked by the above.
The "Stall Stall" warning is all that remains but is unfortunately turned off when IAS<60kts despite being airborne.

It's going to be one heck of a Human Factors course.

[airtren]

It is precisely a matter of knowing your machine, nothing more and nothing less. Knowing what it does, knowing what happens if the various flight states are in operation. It's really a simple thing - it's called professionalism. If the machine is complex then one needs to be able to work on a different level but one needs to prepare. It's called flying and it seems it isn't encouraged these days.

Of course "knowing your machine" is a very important element, and agree 100% with parts of the post that are about that. The training and policies failed to prepare the pilots to avoid the situation (first), and then to recover from it (second).


But the aircraft is not responsible for this - the computer systems aren't responsible for this, the manufacturer isn't responsible for this. The airline is. Isn't it time to stop chasing after red herrings? The accident is the responsibility of the pilots flying and the airline which put them in the situation. It is not due to the complexity of the machine or even the interface but a failure in procedures, training, psychology and CRM. Human factors, gentlemen - focus on these.

....The debate about trim, types of laws etc and whether the aircraft has an influence on the accident is sterile and irrelevant

But I disagree 100% on the parts of your post about the machine, and responsibilities associated to it, which include the procedures that only a manufacturer can develop.

The machine was brought to an extreme state, by a convergence of elements in which the machine itself, and procedures known at the time, had a complex contributing role. As a recovery from that extreme state was not successful, it was a fatal state. Such a scenario was never tested before, and the machine's behavior was not known in its totality. The machine is known better now, and the important resources spent to recover and analyze the CVR, FDR and parts of the machine were worth for that reason as well.

The procedures have been already changed. Recognizing the machine's contribution is a very important element for the improving and progress of technology, to avoid a repetition with the same type of machine, or for making new generation safer machines.

It's one of the elements that moves the technology forward. Not recognizing that would be a big failure for the technologists, for the manufacturers, for the industry.

[CONF iture]

If in a completed stall, at FL35-38, and then ”falling”. Could you recover, and if yes, how do you recover from the stall during the fall?

What strikes me by reading the Airbus Flight Safety Magazine is :

It is important to know that if such a thrust increase was applied when the aircraft is already stalled, the longitudinal effect would bring the aircraft further into the stall, to a situation possibly unrecoverable.

[AlphaZuluRomeo]

What strikes me by reading the Airbus Flight Safety Magazine is :

It is important to know that if such a thrust increase was applied when the aircraft is already stalled, the longitudinal effect would bring the aircraft further into the stall, to a situation possibly unrecoverable.

Indeed. And What strikes me by reading the same sentence is that a situation possibly unrecoverable is not clearly defined. Why would a situation be unrecoverable?
- Because the plane cannot recover ("locked in stall")? That's not demonstrated, and in fact AF447's FDR traces tend to prove the contrary.
- Because the plane may not have the height needed to perform the recovery, this height being larger as the stall is more pronounced/longer held? That's more how I understand "possibly", here. ;)

[Lyman]

In ALT LAW 2, there is no Bank limit, and it is clear that PF was focused (overly so?) on his rolling. Perhaps to the extent that he neglected PITCH. If he wanted climb (and his stick says so) he may have been eager to address the rolling. Isn't Pitch modulated by the computer? If so, that is my point, not the 2.5 g barrier, but the "comfort" g exhibited in the climb which allowed the a/c to lumber up to 38k low energy, to STALL in mush?

Had the a/c STALLED earlier, before it lost its energy, mightn't there have been a NOSE DROP, and an inescapable cue to get the NOSE DOWN?

I am not saying the PF was tuned to his a/c, but if the a/c wasn't trying to supply comfort instead of reality, could this have turned out differently?

AZR. The language re POWER and then possibility of unrecoverable flight demonstrates that the authors do not know what will happen. No harm in that, but it is crystal clear that they are comfortable in this lack of knowledge. The assumption is that all pilots will acquiesce to the instruction. Some pilots like to know WHY? Given the State of the ART it's also clear that to tell these pilots what will happen serves no purpose. There is a message in that.

[CONF iture]

It is important to know that if such a thrust increase was applied when the aircraft is already stalled, the longitudinal effect would bring the aircraft further into the stall, to a situation possibly unrecoverable.

AZR,
The way I see it is :
For obvious reasons a flight test cannot be risked.
AF447 was possibly unrecoverable the way the stall was initially engaged ...

[airtren]

What strikes me by reading the Airbus Flight Safety Magazine is :


It is important to know that if such a thrust increase was applied when the aircraft is already stalled, the longitudinal effect would bring the aircraft further into the stall, to a situation possibly unrecoverable.

Indeed. And What strikes me by reading the same sentence is that a situation possibly unrecoverable is not clearly defined....


I find too that the article and also the presentation need some refinement. The presentation - link posted also by:

.... Airbus power-point presentation on their revised Stall Recovery Procedure (http://orleans.neting.com.es/esa/ESA_Jazz/Airbus%20Stall%20and%20recovery.ppt).

has some ambiguities that may lead to misunderstanding. While the "Loss of speed" for a certain AOA, is mentioned as an important element contributing to a STALL, on page 8, the text "Stall is an AOA problem only. It is NOT directly a speed issue" may be misinterpreted.

While removing the "increase of thrust" from the list of actions for "gaining speed" is understandable because of its effects for the type of engines mount, on increasing the AOA, contributing to the STALL, the "gaining of speed" is still important. It is part of the solution/recovery, and the change of AOA - bring the nose down - is a means to achieve just that. I think more clarity would be helpful, as the training should not have an ambiguity which would allow the interpretation that gaining speed when the nose is down is wrong.

[CONF iture]

It is not due to the complexity of the machine or even the interface but a failure in procedures, training, psychology and CRM. Human factors, gentlemen - focus on these.
Why not including the complexity of the machine or even the interface in the equation ?

It is precisely a matter of knowing your machine, nothing more and nothing less. Knowing what it does, knowing what happens if the various flight states are in operation. It's really a simple thing - it's called professionalism.
I wish it would be that simple - Unfortunately the complexity involved makes it is not.

the manufacturer isn't responsible for this
What to expect when a Manufacturer puts on the market a product that's supposed to correct the pilot's errors to the point that its designer publicly announces that even his housekeeper could fly it ... ?

[Lyman]

On a more concrete note, I still have yet to see the timing of the PF's stick for duration that would not invigorate the Trimmable Horizontal Stabiliser. Offered as proof is the mere statement that "The THS didn't trim because the stick did not linger in NU long enough."

I'm calling bs........ Anyone?

Does some neutral party want to index the SS for duration/trim activation? Because if the THS did not move, and the SS commanded its action, what held it back? G? LAW?

[Old Carthusian]

CONF iture
Quote
'Why not including the complexity of the machine of even the interface in the equation'

Because knowing your machine enables you to deal with its complexity. A level of professionalism is necessary. It is, in fact, a dangerous illusion to regard more modern computerised aircraft as more complex. In fact older aircraft were often the more complex requiring more attention and work. As technology has developed aircraft have in fact become simpler. Certainly aircraft can become even simpler but one cannot attribute what happened to the interface or the complexity of the machine. And if you pause and think how many A330s are flying and how many hours they have flown one cannot call these overly-complex machines. An overly-complex machine could not have survived for such a long time.
We have an aircraft which by all accounts flies well without protections. In fact those who've flown it state that it is one of the better ones to fly manually. We have a culture (that of Air France) in which a certain casualness has developed (an Air France safety audit identifies this). We have certain incidents involving Air France crews which seem to indicate a lack of knowledge of how to handle their aircraft. Putting a machine into an extreme situation then blaming the machine because it is operating outside the parameters it was designed for is futile. The PF put his aircraft into a state where it could not recover. It wasn't the machine that produced this situation but the humans. Understanding why they did so is the important factor here.
As things get safer and we develop more protection against danger paradoxically the danger increases. Humans tend to react to safer situations by dropping their guard. They do not act with caution and thus they pay less attention to safety. This is where training, CRM, culture and psychology all come into play. This is why knowing the machine and professionalism are so important. Remembering that you are responsible for more than one life. But all of this is to do with the people who operate the machine and their responsibility.

[AlphaZuluRomeo]

CONF iture
Indeed, "possibly" as in "not demonstrated, and will not be either way". :D

airtren
the "gaining of speed" is still important. It is part of the solution/recovery, and the change of AOA - bring the nose down - is a means to achieve just that.
Uho... Perhaps is the procedure not perfectly written. On the other hand, I disagree when you write "the change of AoA is a means to achieve a gain of speed" (if I understood correctly?)
It's the other way : the gain of speed is a mean to lower AoA (all other parameters equals). And lowering the AoA is what is important to avoid/exit a stall.

[DozyWannabe]

What to expect when a Manufacturer puts on the market a product that's supposed to correct the pilot's errors to the point that its designer publicly announces that even his housekeeper could fly it ... ?

Here we go again. Once more with feeling, and hopefully for the last time.


Bernard Ziegler was not the "designer" of the A320, though as Engineering Director at the time he did have final sign off
The flight characteristics and systems functionality were tested and signed off by Gordon Corps, the archetypal "pilot's pilot" and successor to D.P. Davies at the ARB
"Correct[ing] the pilot's errors" is only one aspect of Normal Law, another important one being that a pilot can safely fly close to the design limits of the aircraft
As daft as the statement looks in hindsight, Ziegler didn't say anything about his concierge being able to land the aircraft or handle it in a degraded state
If the people still holding on to this nonsense as some kind of affront to the piloting fraternity would let it go (after all it did happen 24 years ago), then discourse would be a lot easier

[Lyman]

Aviation owes its remarkable record of safety in one area.

One: Powerplant. Complexity existed because mechanical solutions could not keep up with how basically simple actual flight is. The Turbine and then the Fan made aviation wicked safe. The question we avoid, the Rhinoceros in the room: Why is it not much safer?

I submit that the actual flight control arena is a Straw man. 447 demonstrates this elegantly.

Carthusian is thus absolutely correct, imo.

Training? Skill? What about the rampant myopia present here on this thread?

AB have crafted for themselves a politically effective position of Carte Blanche from criticism.

With an arrogant ignorance of how simple the machine actually is, and not actually sophisticated as it is presented, they feign "misunderstanding" or "ignorance" on the part of the operator, as always, it is a fact.

It is indeed a machine that is safe and dependable. What is galling is the remarkable stubbornness they display when confronted with obvious blunders in its programming. These blunders include the attitude it takes to reactively defend them.

[CONF iture]

It is, in fact, a dangerous illusion to regard more modern computerised aircraft as more complex.
To the contrary, IMO, the illusion is to regard them as less complex.

We have an aircraft which by all accounts flies well without protections.
Exactly my point.
Cut down in the protections then, they are the ones to bring the over complexity you are not ready to look at.
An even better product will emerge.

If you're not ready to look in that direction as well, I’m afraid you miss a point.
It is a bit like Ziegler who doesn’t want any to touch its baby – It has to be all pilot’s fault :

http://www.crashdehabsheim.net/Films%20video/bd-temoignages.wmv

[CONF iture]

Bernard Ziegler was not the "designer" of the A320, though as Engineering Director at the time he did have final sign off
Bernard Ziegler will be glad to see you did finally promote him from sales department (http://www.pprune.org/6660890-post3230.html) to Engineering Director, not after initially pretending he was not even an engineer (http://www.pprune.org/6076231-post110.html) at that time.

I hope that in your job or life when you put your mark at the end of a document you’re conscious on your involvement ...

Like it or not, Bernard Ziegler is still the father of the 320, and don’t take it too personal if he said stuff you disapprove.
Who’s talking about feelings …

[DozyWannabe]

Bernard Ziegler will be glad to see you did finally promote him from sales department (http://www.pprune.org/6660890-post3230.html) to Engineering Director, not after initially pretending he was not even an engineer (http://www.pprune.org/6076231-post110.html) at that time.

The role he played in the actual specification and design was minimal, as you well know. He signed off on things, maybe did some arbitration - but that's about it.

Like it or not, Bernard Ziegler is still the father of the 320, and don’t take it too personal if he said stuff you disapprove.

That's denigrating Captain Corps' role more than a little, and the only reason more don't know about him was because of his untimely death in 1992.

BZ is the "father of the A320" in the same way Bill Gates is the "father of Windows" - it may have been his name on the press releases but the work itself was delegated.

Like certain other posters, you're fighting 24-year-old battles, which frankly makes you look a little ridiculous. This is about AF447, not AF296 - and there is no evidence - none - that complexity, whether perceived or real played any part.

The Airbus FBW design is here to stay - why can't you get over it?

[NB. If the protections were gone, your hero Asseline would not have been alive to lie about the aircraft in the first place. ]

[airtren]

airtren
the "gaining of speed" is still important. It is part of the solution/recovery, and the change of AOA - bring the nose down - is a means to achieve just that.
Uho... Perhaps is the procedure not perfectly written. On the other hand, I disagree when you write "the change of AoA is a means to achieve a gain of speed" (if I understood correctly?)
It's the other way : the gain of speed is a mean to lower AoA (all other parameters equals). And lowering the AoA is what is important to avoid/exit a stall.
Your rephrasing of my text is still in line with what I meant, in the context of the presentation, so I will explain from a different angle. I will use material from that presentation, as what I referred to was in its context:

The change of "AoA" affects the lift coefficient CI, according to the

CI curve, as a function of AoA. (page 5 of that presentation).

The CI is a member of the "lift" equation - see bellow - and thus it affects the "lift":

Lift = 1/2 pSv**2Ci, (page 4 of that presentation)

(where: p = air density, S=wing surface, v=CAS, v**2 is square of CAS, Ci=lift coefficient)

Examining just from a pure Mathematics perspective, given that the S is a constant, the other two elements that affect (and will increase) the "lift" are the "p" and "square of v" (if they increase).

Furthermore, if theoretically and abstractly one can assume that AoA does not affect speed - so the speed stays constant - as CI cannot go above a Maximum Value, one may try to change AoA as much as he wants, but that (Max) CI, with an insufficient "v" (speed), and insufficient "p" may still result in insufficient "lift" and thus no return to normal flight.

So my point again is that the change of AoA affecting the CI alone, may not be sufficient to cause the return to normal flight.

It is rather the combined effect of the AOA on the CI, with the AoA effect on increasing the speed and thus the "square of v" that from a possible "speed" insufficiency in a "insufficient lift", to a "sufficient speed", which by resulting in a sufficient "lift" makes the a/c return to normal flight.

I can understand why the written presentation may attempt to reduce the aspects of recovery from Stall that may be look too acrobatic, because of the drastic changes of speeds, and altitude. But I can see how the verbal communication during the presentation, or a training session may be very explicit on the dramatics of the change of AoA to aggressive Nose Down, and letting the a/c in a Nose Down fall to gain sufficient speed, to change the AoA again, to level off, and transform the falling speed into horizontal speed, get sufficient "lift", to get to normal flight.

....

You say, the "gain of speed is a means to lower AOA".

I don't see how the "gain of speed" has necessarily a "lower AoA" consequence. Perhaps your elaborating would help.

[airtren]

CONF iture

...It is, in fact, a dangerous illusion to regard more modern computerised aircraft as more complex. In fact older aircraft were often the more complex requiring more attention and work. As technology has developed aircraft have in fact become simpler.



In general - and thus independent of specifics pertaining to a certain manufacturer - the modern/current airplanes are hugely more complex, and there is a lot more work and attention than before when summing up all the work and attention on all the components packed into one airplane.

That more complexity and that more work and attention may not be obvious to a casual observer, but it is there, even if hidden by the huge reduction in electronics components dimensions, huge advance in electronics integration, and modularization, or by the physical character of the components - software - and the stages and different areas, disciplines, R&D, development or manufacturing facilities in which the attention and work is performed.

[RR_NDB]

Hi,

aitren: the modern/current airplanes are hugely more complex

:ok::ok::ok: (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-55.html#post6733381)

And despite this immense complexity the basic is the same:

When the plane degrades (by any reason) you need:

1) Feel it
2) Aviate it (the same for all models)

And this requires a SIMPLE THING: Known your machine in it's basic config.

may not be obvious to a casual observer

A Professional knows everything related and involved in his mission, specially when Murphy Law acts.

[BOAC]

Not quite sure how we got to the lift equation in a thread about loc, but I think there may be some confusion growing here between a 'stall' and 'insufficient lift' for flight which can be two completely different phenomena.

[SandyYoung]

DW,

A minor point - Windows appeared on the original Apple Mac well before Bill G. was involved. IIRC it was on the Apple Lisa before that.

I'm told the mouse part of the WIMPs interface (Windows, Icons, Menus and Pointing devices) was a spin-off from a Xerox trackball used in missile guidance well before the Mac.

I mention this only because MS and IBM are often given the credit for the PC. They were well behind.

[DozyWannabe]

@SandyYoung - hence the capitalised W in "Windows" (implying the product, not the concept). Xerox invented it, Apple nicked it, Microsoft copied it - but the best early implementation was Workbench on the Commodore Amiga. Anyway - back to the regular scheduled programming...

[gums]

Thanks, BOAC. ANd speed is a huge part of the lift equation, like a "squared" component.

So if I hold the same gee ( read lift you can feel in wings level flight), and I increase speed, then I can use a lower AoA for the same amount of lift.

Lowering AoA is the faster solution - get outta the part of the Cl curve that shows less lift and you also reduce induced drag. And for those jets with the underslung motors, adding power is not a good idea in some cases due to the nose up pitch moment.

For the swept wing jets the induced drag is a lot more evident that in the straight wings. The deltas were the worse ( or most low aspect ratio wings), then the good wings we developed in the 70's and 80's had much more gentle stall entries and less buffet and better directional control at high AoA. This is an insidious feature of the better wing designs we now have that may have contributed to the AF447 crew's failure to recognize their state and take appropriate corrective action. The lack of a good AoA indication also comes into play. That string taped to the side of the cockpit window would have been more helpful than the ambiguous stall warnings and such that the crew dealt with.

After talking with several folks here offline, I am suspecting a management influence on all the "laws" and "protections" and Otto functions versus "neat" features that the pilots demanded. The jet appears to be very well designed and easy to fly even with all the "old" mechanical/hydraulic control systems. And that is what bugs many of we old dinosaurs. I can't speak for all of us, but I would guess we would all like a very clear control system implementation we could hang our hats on when all the Otto functions and bank angle limits and pitch angle limits and such go away.

If we, the SLF, wish to have "systems managers" up front versus folks that can fly the jet with little "help", than I'll cease to be SLF. Scares the hell outta me.

[Lyman]

In no other a/c but the A330 is it more important to isolate NORMAL LAW from everything else. The type is trained to NL, and there is a disconnect in making anything except NORMAL LAW available in emergent or off standard flight path.

Except basic aero. Basic. It is counter intuitive to think other Laws in some sort of descending order will be helpful in an odd, or rare condition.

The a/c is dependable enough to eliminate the need for anything other than DIRECT LAW in such circumstances... Nothing but trouble if Pilots have to remain current in several ways to approach unusual conditioons.

As we see here.

[DozyWannabe]

After talking with several folks here offline, I am suspecting a management influence on all the "laws" and "protections" and Otto functions versus "neat" features that the pilots demanded.

And at least one who told you there wasn't any. *All* the functions went throug hthe engineering pilots.

If we, the SLF, wish to have "systems managers" up front versus folks that can fly the jet with little "help", than I'll cease to be SLF. Scares the hell outta me.

That is press-fuelled garbage - I guarantee you no-one from Airbus ever said pilots should be no more than "systems managers".

[AlphaZuluRomeo]

Your rephrasing of my text is still in line with what I meant
Thanks for confirming it :)

So my point again is that the change of AoA affecting the CI alone, may not be sufficient to cause the exit from Stall.
:confused: :confused:
As for the maths: I'm sorry, I'm not fond of maths, I must say. Logic is enough to me :)
For that reason, I won't comment on your formula.

You may be unstalled (i.e. your wing is flying, producing lift & allowing control) but not have a CI big enough to support your weight. Then, you're descending. But no more stalled. :ok:

You say, the "gain of speed is a means to lower AOA".

I don't see how the "gain of speed" has necessarily a "lower AoA" consequence. Perhaps your elaborating would help.
I wrote : "the gain of speed is a mean to lower AoA (all other parameters equals)" (my underlining)

Reverse: For the same velocity vector, your AoA is lower if you fly quick than if you fly slow.
That's why I wrote that if you fly quicker, you'll lower your AoA. Note that it was the spirit of the (now discarted IIRC) "approach to stall" procedure: To escape "falling" into an actual stall with more speed ; Without loosing altitude (<= maintaining the (level) velocity vector)

My point is : Speed is a consequence. AoA is what matters.
If stalled (or nearly stalled), you must lower AoA, be it by altering flight path (velocity vector => push the damn stick) or by gaining more speed (*)
The former is more efficient, as pitch control is a direct AoA control. That doesn't mean a bit more speed won't help: it will. But what you seeks, ultimately, is not more speed but less AoA.

(*) which, as shown above, will allow you a lesser AoA for the same flight path, or a higher flight path with the same AoA.

[airtren]

...
As for the maths: I'm sorry, I'm not fond of maths, I must say. Logic is enough to me

The beauty of it is that it can embed a certain logic in an abstract way in an equation, allowing reference to the logic, or its elements, just by way of referring to the equation, and its elements...


You may be unstalled (i.e. your wing is flying, producing lift & allowing control) but not have a CI big enough to support your weight. Then, you're descending. But no more stalled.

Exactly!

My point is : Speed is a consequence. AoA is what matters.
The explanation helped seeing that I've missed your implicit reference to the speed vector's scalar (magnitude) as a constant element, with the changes of the vector's direction coinciding with the AoA changes, and vector axial components changes.
With the rephrasing, I think we're in sync (unintentional rime). :)
The "speed change” I was referring to “is a consequence of change of AOA" , with both energy conservation and momentum conservation playing their roles.

[CONF iture]

Also, CONF is a long-time hater of everything the 'bus stands for, so of course he's going to say that.
If the protections were gone, your hero Asseline would not have been alive to lie about the aircraft in the first place.
Once again, behave your comments DozyWannabe.

That I look "little ridiculous" in your eyes is OK to me.
If you are at the end of the rope for your argumentation, I cannot help you.

[Lyman]

Sorry, who was Asseline employed by? What was his rank in the company?

'Reality' is a boulevard with a reciprocal. It cuts both ways.

The company beverage at Airbus is 'KoolAde'...tm

[jcjeant]

Hi,

And another news (transparency and credibility .. we said .. ?)

Rio-Paris: l'Agence européenne de la sécurité aérienne a-t-elle quelque chose à cacher ? - Libération (http://www.liberation.fr/societe/01012363930-rio-paris-l-agence-europeenne-de-la-securite-aerienne-a-t-elle-quelque-chose-a-cacher)

Google Traduction (http://translate.google.be/translate?sl=fr&tl=en&js=n&prev=_t&hl=fr&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.liberation.fr%2Fsociete%2F01012363930-rio-paris-l-agence-europeenne-de-la-securite-aerienne-a-t-elle-quelque-chose-a-cacher&act=url)

[VGCM66]

Air France Flight 447 Crash Probe Shows Confused Crew, Misread Instruments - Bloomberg (http://www.bloomberg.com/news/print/2011-10-05/air-france-flight-447-crash-probe-shows-confused-crew-misread-instruments.html)

[jcjeant]

Hi,

I just made a little review of the French press this past October 5 dealing with the matter of legal side AF447
I think that I am right in reckoning that the process will be in 10 or 15 years (St Odile and Concorde style) and no doubt many players will disappear naturally before those days (even the "experts") and everything will be already a "souvenir" in the shadow
It goes without saying that this does not show the famous independence .. the famous transparency .. the famous search for the truth .. very credible to the general public

[AlphaZuluRomeo]

airtren
We're on synch indeed. :)
Except perhaps re-the beauty of maths, but it's a religious matter for me (joking).:p

jcjeant
How interesting! Let's hope the "technical constraints" may be soon solved...

[infrequentflyer789]

Sorry, who was Asseline employed by? What was his rank in the company?

'Reality' is a boulevard with a reciprocal. It cuts both ways.


Asseline was AF, just like crew of 447.

Rank ? Not sure, but I have seen at least one reference to him being (ironically) one of those who were consulted by Airbus in the flight control system design. Since there are some here who believe Airbus didn't consult pilots on the design... that would imply Asseline was not a pilot.

[infrequentflyer789]

Hi,

And another news (transparency and credibility .. we said .. ?)



I wonder what severity Airbus suggested for the issue. If regulator overruled them and downgraded it, that might even let Airbus / Thales off the hook for the pitots.

[infrequentflyer789]

In no other a/c but the A330 is it more important to isolate NORMAL LAW from everything else. The type is trained to NL, and there is a disconnect in making anything except NORMAL LAW available in emergent or off standard flight path.


You should at least be referring to the range of Airbus models, which all (since A320) have same modes.

Also, so does Boeing (777, not sure on 787 but believe it is the same). Secondary mode on 777 is very similar to alt law on bus - still the same control laws but no protections (which on 777 are "soft" only and operate through the artifical feel). 777 also has direct mode too.

[wozzo]

Air France Flight 447 Crash Probe Shows Confused Crew, Misread Instruments - Bloomberg (http://www.bloomberg.com/news/print/2011-10-05/air-france-flight-447-crash-probe-shows-confused-crew-misread-instruments.html)

I think there is some new information in that report:

“I’ve lost VSI,” the junior co-pilot said of the Airbus’s vertical-speed indicator, according to a recording detailed in the report from court-appointed experts. In fact, the instrument was functioning normally, its analog needle immobilized at the lower limit because the plane was hurtling toward the ocean at 15,000 feet a minute, the document seen by Bloomberg News shows.

Makes horrible and sad sense: misinterpretation of VSI => no knowledge of losing height fast => unaware of stall => misinterpretation of ambient noise as overspeed.

[auraflyer]

Xerox invented it, Apple nicked it, Microsoft copied it

Not quite. People at Xerox PARC invented the idea - but their windows were not able to overlap. They couldn't figure out how to do overlapping windows. (The issue has to do with the arbitrary shapes that can be formed when one window is overlaid by multiple others, which you need to do clipping of content when drawing, and when refreshing.)

Apple toured the facility (with permission) and their engineers saw the interface. Unaware that PARC engineers hadn't been able to do overlapping windows, Bill Atkinson actually worked it out. In assembler. (Anyone who has programmed 68k Mac should be aware of 'regions', which is how it's done.) That was one of the most important parts of getting the interface into sellable form.

It also helped that some of the Xerox people (e.g. Larry Tesler) were so impressed with the Apple people that they joined the Apple team working on the Lisa.

There's a lot of cool material about this on the web, but Hertzfeld's book "Revolution in the valley" is a really great read on this subject.

Edit: mixed up Bill and Andy as the inventor. See the original patent (http://patft1.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=%2Fnetahtml%25%2FPTO%25%2Fsearch-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN%2F4622545).

[Lyman]

Hi wozzo. Here we see a drastic hole in the popular myths. "I've lost my VSI". Erm, "How's yours?" This narrow, myopic tilting at published data driven conclusions is getting bizarre.

We are left to flutter in the winds of our need to know, and the thin soup served us by BEA.

It didn't happen this way....

Four minutes is still four minutes, and each fragile crystal of "conclusion" is less than useless when weighed against the totality as recorded.

There is no conclusion that the Thales were the cause, there is no conclusion that the a/c climbed to STALL with Pilot input only, etc. etc.

In a free and open society, isn't it clear that there are stones in the soup?

Yet every (nearly so) uttering is the whine of Pilot error.

It's in there (PE), oh yeah. So is a great deal more, and EASA is holding back.

BEA are not the problem, they are the messenger. And Mercury is muzzled. One has some trust of the science in BEA, and none in the wags who call their orders.

infrequentflyer789. I isolate the A330; it is in the family, but it is the only TWIN which does what it does.

Haven't the 330's been removed from Rio-Paris? See?

[wozzo]

"I've lost my VSI". Erm, "How's yours?"
Same. And therefore subject to the same misinterpretation.

Also, the info does not come from BEA.

[Turbine D]

Dozy

I've sat on the sidelines watching and reading lately. Your posts were at one time informative and interesting to read, but have turned into total protection of Airbus recently. Airbus doesn't need protection, they are experts at "protections".

I have got to go with gums on this. The computer system, e.g., Alternate Law 1, Alternate Law 2 and subsets of Alternate laws are very confusing. Normal Law and Direct Law are very clear: Normal Law - the computers fly the plane and the pilots watch, Direct Law - the pilots fly the plane and the computers watch. That is simple. The in-betweeners are a mish mash of: You have this but not that except when this is this or that is that....

Think about it, in the case of AF447, they had at most three minutes to determine what was wrong, what was going on and what to do, with the balance of time being on the express elevator to the sea. From a technical and engineering point of view, here is what I see wrong on Airbus' part in this saga:

1. Airbus failed to handle the pitot tube problems in a manner that they should have.

2. Airbus failed in their risk assessment/risk abatement to adequately cover the total waterfront, e.g., total flight envelope. They were nearly mute on flight problems at high altitudes and speeds. Guess they assumed problems couldn't happen there.

3. Airbus failed to provide complete key memorization items in their flight instructions for the A-330, leaving out for the most part, high altitude and high Mach cruise situations.

Now you can say this is Monday morning quarterbacking, but it isn't. It is good common sense, business best practices - risk and risk abatement processes that should have been in place but were not.

You can also say and you have on many occasions, the plane did exactly what it was supposed to do, but in reality, it crashed. That was not Airbus' intent I am sure, nor was it the pilots flying or Air France's intent either.

Like it or not, Airbus has the leading role, it is their airplane (a good one at that), their design, their computer control flight system. Airbus therefore has or should have the leading role in establishing all of the criteria, instructions, do's and don'ts to pass along to individual airlines who buy their planes and then the pilots who will fly them and even train them. Additionally they have the lead role in determining what should be done when critical monitoring/detection devises develop a history of not performing to expected standards or expectations.

Prior to AF447, there was a substantial case history established on the pitot tubes (selected and installed by Airbus) which indicated there was an icing sensitivity problem. A good risk assessment/risk abatement analysis (an industry best practice) would indicate this to be a significant safety item needing rapid attention. Things that happened in flight on other airplanes would be an indicator that sooner or later a flight crew could/would respond incorrectly. As in the role of leader, Airbus must not have/didn't push the issue hard enough with EADS, or so it seems or didn't view correctly the critical nature of pitot icing at high altitude and high Mach.

AF447, three minutes to go (not knowing that at the time), A/P come off, A/T come off, the stall warning sounds, the nose is slightly down and one wing is lower than the other. We are in Alternate, is it 1 or 2? Going too fast? Going too slow? What is the speed? What are the protections? What do we have and what don't we have? What does the memorized list developed by Airbus say? Do we have a memorized list for high altitude/high Mach? That was the situation. Now Airbus did do a good risk analysis/risk abatement for low speed, low altitude situations, landings, T/O's, thus developed the memory lists. But they stopped short. In fact, if you apply the low altitude low speed do's to high altitude/high Mach, it probably makes the problem worse. What happens to THS flight protection in Alternate law? What's the AOA? Confusion? Help? Panic? 3 minutes to sort things out. Cavalry charges, single chimes after single chimes, single chimes every 5 seconds, lots of crickets? Get the gist?

Airbus had the lead on pitot tubes, they selected and installed them, they had the wealth of data regarding icing and what other airline/Airbus aircraft did at cruise when pitots iced. They knew there was a difference between manufacturers and performance/non-performance. What did they do about it? Did they do a risk assessment/risk analysis? Was it deemed to be a hoe-humer or a critical problem when flying at high altitudes and high Mach? What did they advise EADS to do? Airbus has the lead here, not EASA. Did EASA respond appropriately based on Airbus' strong recommendations? Did Airbus have a strong recommendation?

So at cruise in the middle of a moonless night in the middle of the Atlantic Ocean in the active ITCZ at some level of turbulence the A/P quits, and computers go off line, partially but not fully and the plane doesn't even remain in level flight. Now Airbus knew the AOA was a critical key component to assure safe flight, but where was the indicator to know what it was and where it was going? Is there a key memory list, e.g., level wings fly pitch and power? What should be the correct pitch setting when you have no speed indications?

And I could go on in more detail and ask more questions, but I won't. I think there is enough to illustrate that Airbus shares much responsibility as do the flight crew, the airline and even EASA if they relaxed on an Airbus' "Strong" recommendation, if there was one. But Dozy, to continue to protect Airbus is fruitless, it is like pi**ing into the wind, sooner than later you are going to get wet and I think you are getting wet.

[Gretchenfrage]

“I’ve lost VSI,” the junior co-pilot said of the Airbus’s vertical-speed indicator, according to a recording detailed in the report from court-appointed experts. In fact, the instrument was functioning normally, its analog needle immobilized at the lower limit because the plane was hurtling toward the ocean at 15,000 feet a minute, the document seen by Bloomberg News shows.

What about the digital readout? Should still have been there.
This shows quite clearly that all the advocates about "it's on the screens, just read it; who needs feedback?" are naive:
In stress, humans read badly. We need either tactile feedback or a more clear display than many of the digital displays.
Simply telling the pilots to read the five-color s#!thouse on reflecting and worn-out screens with a multitude of same color digital indicators and FMAs with five windows on three rows with zillions of different abbreviations is, to cite the Borg, futile.....

I do realize that there is no feedback on VSI, but there is a more intelligent display mode than the donkey's dick that just disappears on the lower end.
It's the tape-style color coded indicator on a MD11. It stays filled white and is way more legible, even under stress.

[AlphaZuluRomeo]

I think there is some new information in that report:“I’ve lost VSI,” the junior co-pilot said(...)
Also, the info does not come from BEA.
Didn't it?

BEA's interim report #3, CVR transcript
2 h 11 min 58

FR :
F/O (PF) : J’ai un problème c’est que j’ai plus de vario là
CPT : D’accord
F/O (PF) : J’ai plus aucune indication

EN translation :
F/O (PF) : I have a problem it’s that I don’t have vertical speed indication
CPT : Okay
F/O (PF) : I have no more displays


“I’ve lost VSI” is just another translation for “j’ai plus de vario là”.




Haven't the 330's been removed from Rio-Paris? See?

AF443 : B777-300ER
AF445 : A330-200 (this was AF447 before)

Hardly conclusive, IMO...:confused:

[DozyWannabe]

Dozy

Your posts were at one time informative and interesting to read, but have turned into total protection of Airbus recently. Airbus doesn't need protection, they are experts at "protections".

If that is the case then I suggest you read what I've been posting in isolation from what others (including yourself, it would appear) chose to read into what I was saying.

I have got to go with gums on this. The computer system, e.g., Alternate Law 1, Alternate Law 2 and subsets of Alternate laws are very confusing. Normal Law and Direct Law are very clear: Normal Law - the computers fly the plane and the pilots watch, Direct Law - the pilots fly the plane and the computers watch. That is simple. The in-betweeners are a mish mash of: You have this but not that except when this is this or that is that....

Then you didn't read what I was saying - which is that at the most basic level, all a pilot has to understand about the control laws is that you have hard protections in Normal Law, but do not have them in any of the other laws. What that means in the case of this accident is that as such, pulling up and continuing to pull up in the face of a Stall Warning is just as dangerous as it would be in any other airliner once Normal Law is lost.

The sub-modes are there purely for engineering and systems management purposes - as I said, think of them as the different systems configurations that would have been handled by the Flight Engineer on aircraft of earlier generations in the case of damage or failure. Gums knows his stuff, there's no doubting that - but he has got it into his head that the Normal Law protections are akin to autopilot limitations, when in fact they give the pilot considerably more leeway than that (I sent him along some of the Flight articles that covered the A320's development as evidence).

Think about it, in the case of AF447, they had at most three minutes to determine what was wrong, what was going on and what to do, with the balance of time being on the express elevator to the sea.

They'd have had a lot longer if the PF had not started pulling back on the sidestick and continued to do so for the majority of those three minutes. If this was any other aircraft this would have been an open-and-shut case, but because there are those on here that will continue to insist that the computers must be to blame in any Airbus accident, we're still going over the same stuff months later.


From a technical and engineering point of view, here is what I see wrong on Airbus' part in this saga:

1. Airbus failed to handle the pitot tube problems in a manner that they should have.

They told the operators to fix it and sent out bulletins to pilots explaining workarounds until such time as the fixes were completed - what more could they have done without grounding the entire fleet (which prior to this accident would have looked like overkill)?

2. Airbus failed in their risk assessment/risk abatement to adequately cover the total waterfront, e.g., total flight envelope. They were nearly mute on flight problems at high altitudes and speeds.

Them and the rest of the industry.

Guess they assumed problems couldn't happen there.

That's a little bit of editorialising from you. I think it's fairer to say that - like the rest of the industry - they assumed that pilots would be sufficiently qualified and knowledgable to recover from most high-altitude problems.

3. Airbus failed to provide complete key memorization items in their flight instructions for the A-330, leaving out for the most part, high altitude and high Mach cruise situations.

Could you be more specific?

You can also say and you have on many occasions, the plane did exactly what it was supposed to do, but in reality, it crashed. That was not Airbus' intent I am sure, nor was it the pilots flying or Air France's intent either.

It wasn't Bombardier's or ColganAir/Continental's either, but the sad truth is that if you shave the training budgets to the extent where basic airmanship is deprecated in favour of checking only up to the onset of warnings then you will start to get problems.

As in the role of leader, Airbus must not have/didn't push the issue hard enough with EADS, or so it seems or didn't view correctly the critical nature of pitot icing at high altitude and high Mach.

Not wanting to nitpick, but do you mean EASA (European safety authority) rather than EADS (Airbus's parent company)? I'm sure that Airbus went into consultation with EASA and the airlines and together they determined what the response should be. For better or worse, it seems to have been assumed by the industry in general that problems at high-altitude by their nature should buy the pilots enough time and altitude to remedy the situation. Even the most extreme examples of UAS upset prior to AF447 led to relatively minor level busts rather than significant control difficulties - so even if Airbus came to the discussion with a serious AD in mind, it is likely that the airlines would have pushed back at the prospect of large chunks of their fleets spending weeks in MX.

AF447, three minutes to go (not knowing that at the time), A/P come off, A/T come off, the stall warning sounds, the nose is slightly down and one wing is lower than the other.

OK -so we're not in any danger yet. Let's not touch the controls until we're sure what's happening.

[Actual response : Immediate grip on the PF's sidestick including a significant nose-up command, far in excess of what would be required to bring the nose back up to S&L. ]

We are in Alternate, is it 1 or 2?

Doesn't matter. Anything other than Normal => No hard protections. We need to be more careful with the inputs (though no more careful than in any airliner without protections)

Going too fast? Going too slow? What is the speed?

We don't know, so fly pitch and power until things are stable.

What are the protections?

See above - there aren't any (or to be more precise there aren't any that will counteract pilot demands).

What do we have and what don't we have? What does the memorized list developed by Airbus say? Do we have a memorized list for high altitude/high Mach?

Pitch and power. That's just airmanship - no memory list should be necessary (although admittedly it would likely have helped).

That was the situation. Now Airbus did do a good risk analysis/risk abatement for low speed, low altitude situations, landings, T/O's, thus developed the memory lists. But they stopped short.

As did every other manufacturer.

In fact, if you apply the low altitude low speed do's to high altitude/high Mach, it probably makes the problem worse.

Well yes - the procedure the PF appeared to be closest to following was in fact the low-altitude Wind Shear/Microburst escape - although no procedure was in fact followed to the letter.

What happens to THS flight protection in Alternate law?

Same as the others - it goes away - so we need to be careful.

What's the AOA? Confusion? Help? Panic? 3 minutes to sort things out. Cavalry charges, single chimes after single chimes, single chimes every 5 seconds, lots of crickets? Get the gist?

We're getting Stall Warnings - we've had them for a minute. Why then is our nose at 15 degrees up?

[Answer : Because the PF was holding it there.]

Did Airbus have a strong recommendation?

Yes - replace them as quickly as [the airlines] were able (see above).

Now Airbus knew the AOA was a critical key component to assure safe flight, but where was the indicator to know what it was and where it was going?

Same place it was on every other modern airliner - nowhere.

Is there a key memory list, e.g., level wings fly pitch and power? What should be the correct pitch setting when you have no speed indications?

The assumption was probably that basic airmanship would preclude a 15 degree nose-up pitch at high-altitude - unfortunately relying on that does not appear to have been enough.

And I could go on in more detail and ask more questions, but I won't. I think there is enough to illustrate that Airbus shares much responsibility as do the flight crew, the airline and even EASA if they relaxed on an Airbus' "Strong" recommendation, if there was one.

Which I've never argued with, if you go back over my posts on the subject - my contention has been with those that have argued that there is something fundamentally wrong with the aircraft design and that as such Airbus must carry the whole can.

But Dozy, to continue to protect Airbus is fruitless, it is like pi**ing into the wind, sooner than later you are going to get wet and I think you are getting wet.

OK - let me make this as clear as I can - I'm not "protecting Airbus". I'm simply taking issue with some posters on here that are not discussing the factors of the case honestly, but instead are coming to the table with their pre-conceived notions about why they dislike the Airbus FBW design and are trying to hammer the facts of the case to fit the mould of their prejudice.

At least one poster continues to come up with ever more lurid theories about how it must have been the aircraft's fault. Indeed, insisted until *very* recently that the VS must have broken off in flight, then made excuse after excuse including how there must have been a software bug that popped the spoilers on one side, that the THS control software suffered a glitch and ordered a runaway trim without the pilot's knowledge...

Others are trying to turn this into an argument about a 23-year-old accident in which the pilot thought he was better than he was, crashed the aircraft and killed three people (two of them children) in the process - and consistently refused to take responsibility for his actions since, making up excuse after excuse as every one was disproven by the investigation.

All of this comes from the patently false idea that Airbus and airline management were in cahoots with each other to develop an aircraft that would de-skill the job of airline pilots and reduce them to "systems operators" akin to any other office monkey. Even gums, who clearly deserves to be taken seriously in most respects, harbours this idea in the background of his thinking - which is a shame because it clouds the rest of what he's saying.

I have never said that Airbus should not shoulder some responsibility - in fact I've always been at pains to point out that because of the pitot tube issues there is no way they can avoid it. However, I do take issue with some posters going on the "same old sh*t" tour when it comes to incidents involving the FBW Airbus family and bringing up factors that have no bearing on the case (sidestick vs. yoke) or could be applied to the whole industry (lack of preparation for high-speed stalls, recurrent training cut to the bone).

So please - if you're going to level this kind of stuff at me, please have a look at what I'm actually saying - in isolation from what others claim I am saying.

[EDIT : I hope IGh won't mind me borrowing this image from his post on the ANA 737 upset thread in R&N, but it sums up more succinctly than I could what I believe to be the crux of the issue regarding the crew response (mitigated in this case by a poor attitude to training on the part of the industry):

http://i675.photobucket.com/albums/vv118/IGhhGI/Startlefactor.jpg
]

[wozzo]

Didn't it?
BEA's interim report #3, CVR transcript
“I’ve lost VSI” is just another translation for “j’ai plus de vario là”.

Ah, OK. So the new report indicates that investigators (BEA or others) seem to be sure that VSI indeed was functioning properly and the PF was misreading. Small step, I know.

[averow]

Very fine and succinct summary. The problem going forward is to reinforce that there is no substitute for CRM. Rare events can and do happen if one gets lulled into a sense of complacency in ones profession. Trainers, designers and airline companies need to acknowledge this paradox: technology and design may be lulling the next generation into thinking that the machines are foolproof.

[lomapaseo]

These kind of technical discussions will get out of hand if we decide to express legal arguments about fault in this forum.

It's bad enough about expressing opinions about how to redesign a complex system, although soothing to the soul. Expressing desires for this and that seems to be quite adequate.

[Clandestino]

Unfortunately, as the aeroplane drops from under the pilot and its nose dips earthward, the pilot's "instinctive" reaction will be to haul back all the harder on the stick. If his imagination works with the faulty images, if he images that the stick is the airplane's up-and-down control, he can hardly help hauling back on the stick. This instinctive reaction will be especially impulsive and uncontrollable if the pilot has failed to sense the coming of the stall, and the stall takes him by surprise.

And that is the real danger of stalling: this faulty reaction to the stall, rather than the stall itself. It is quite rare that a pilot is kiled simply because he stalled. But it happens with tragic monotony that a pilot is killed because, stalled when he did not expected it, he either fails to recognize the stall for what it is, or fails to control that impulsive desire to haul back on the stick: he clamps the stick back against his stomach in a terrified cramplike effort to hold the aeroplane up, and thereby makes the stall worse or converts it into spin.

Questions:
1. Who wrote that and when?
2. What was the warning about technology and nature, made by the famous writer, who met his doom while flying an F-5?
3. What is written in Ecc. 1:9?

[RetiredF4]

1. Stick and rudder, 1944, Wolfgang Langewiesche (http://www.ebay.de/itm/STICK-AND-RUDDER-EXPLANATION-OF-THE-ART-OF-FLYING-/220815491948?pt=Antiquarian_Collectible&hash=item3369a1036c#ht_709wt_950) also he didn´t die in an F5, but at the age of 95 in 2002.

I try a potshot at questions two and three:

2. The theory of flight often fails to show the pilot the most important fact in the art of piloting, -the angle of attack- and how it changes in flight.

3. The working speeds of an airplane


Very neat telling from Page 75, i like that one:

Certainly some instrument is needed that would tell the pilot exactly what his angle of attack is, that is, how much buoyanncy he has, how close he is to stall. But the art of flying is still in a primitive state . The most important fact about an airplane´s flight condition is not indicated by an instrument. This is not because such an indicator cannot be built but because designers don´t apreciate the need for one.
Perhaps they are right, -too many pilots don´t know what Angle of Attack is in the first place, and such an instrument´s indications would be meaningless to them.


No big changes happened since 1944, me think!

[Clandestino]

That was pretty quick, RetiredF4. 1 out of 3 is not bad.

You're correct that Wolfgang Langewiesche did not die in aeroplane crash. When we mentioned him, his son, William, is pretty good aviation writer too. However, the fellow I was referring to in the second question definitively went out alone in F-5, never to return. His worldwide fame is mostly based on the single shortish book, that only slightly relates to flying. His warning was very general, simple, true and mightily applicable to both AF447 and FBW Airbi.

Answer no2 is way off mark. No3 is too but with No big changes happened since 1944, me think!...you got pretty close and I'd certainly agree with that.

[OK465]

de Saint-Exupéry and there ain't nothin' new under the sun.

Better example: forgive them for they know not what they do...

Back to the Cricetinae Circumvolution

[VGCM66]

The noose is tightening:

Air France 447: the facts and what's behind them - Learmount (http://www.flightglobal.com/blogs/learmount/2011/05/air-france-447-the-facts-and-w.html)

From:

AF447 investigation (http://www.flightglobal.com/page/af447/)

Good read even if it is still unofficially.

On top:

AF447 victim families hear damning evidence against airline | Plane Talking (http://blogs.crikey.com.au/planetalking/2011/10/06/af447-victim-families-presented-with-damning-evidence-against-air-france/)

[CONF iture]

so even if Airbus came to the discussion with a serious AD in mind, it is likely that the airlines would have pushed back at the prospect of large chunks of their fleets spending weeks in MX.
That’s erroneous and you have been answered on that point already here (http://www.pprune.org/6715823-post975.html) and here (http://www.pprune.org/6717915-post981.html).

[DozyWannabe]

So where would they have fixed them CONF - on the apron? Even if the whole fleet didn't have to be grounded, you'd still have large chunks of it on the ground having repairs and tests done.

[Bill G Kerr]

3 ...nothing new under the sun.

[jcjeant]

Hi,

So where would they have fixed them CONF - on the apron? Even if the whole fleet didn't have to be grounded, you'd still have large chunks of it on the ground having repairs and tests done. Ask Air Caraibe .. they know how it was before Air France ....

[DozyWannabe]

Sorry jc, I'm too dumb to "get" vague generalisations - knew how *what* was before Air France?

[Graybeard]

Dozy:
So where would they have fixed them CONF - on the apron? Even if the whole fleet didn't have to be grounded, you'd still have large chunks of it on the ground having repairs and tests done. Your lack of knowledge of airline maintenance ops is glaring.

[DozyWannabe]

How so, GB? Surely if they're being worked on they can't fly - the replacement schedule that was agreed was that the work would be done when the aircraft came in for their regular maintenance check. People have been arguing that the response should have been stronger than that - so me asking how that would have worked is a genuine question, which is:

Given an AD that required work before the type was allowed to fly again and the schedule that was actually agreed with the SB as extreme ends of the scale, what is there in terms of middle ground that would have satisfied those who were saying that the latter was not enough?

[Lonewolf_50]

The thing that hath beene, it is that which shall be: and that which is done, is that which shall be done; and there is no new thing under the sunne.


Nothing new under the Sun, but ever few years, there seems to be something new under the Apple. :E


One of the oldest rules in aviation remains something like this:

"You cannot defy the law of gravity, but you can break it temporarily, with lift and thrust as your accomplices."

[CONF iture]

So where would they have fixed them CONF - on the apron? Even if the whole fleet didn't have to be grounded, you'd still have large chunks of it on the ground having repairs and tests done.
Where have you seen those large chunks of 330/340 on the ground when finally EASA woke up in AUG 2009, after the war, to implement the AD 2009-0195 (http://ad.easa.europa.eu/ad/2009-0195) for pitot probes replacement ?

[DozyWannabe]

That's just the old "Tombstone Imperative" in action. SBs and ADs that would have been considered overkill before all of a sudden look a lot more sensible. Before the crash, you can bet the airlines would have balked.

They may not have been willing to expedite those repairs for the sake of a few level busts - but it becomes a whole different ball game when you lose an airframe and everyone in it.

[infrequentflyer789]

I have got to go with gums on this. The computer system, e.g., Alternate Law 1, Alternate Law 2 and subsets of Alternate laws are very confusing.


I almost agree - from an engineering perspective the gradual degradation makes sense (and Boeing must have htought so too as theirs is practically the same), but if pilots aren't trained in all the modes, they might as well be labelled "crash mode".

Only issue is that in direct (in A or B) I think you're hand-flying all the way home (or to divert). After what we've heard on training, SOPs etc., isn't there a significant risk in asking todays pilots to hand fly for what maybe a few hours, after possibly only a minor or transient issue ? Maye it is better to keep the in-between mode, which allows (in A and B I think) A/P to be re-engaged when things are stable again ?


1. Airbus failed to handle the pitot tube problems in a manner that they should have.

2. Airbus failed in their risk assessment/risk abatement to adequately cover the total waterfront, e.g., total flight envelope. They were nearly mute on flight problems at high altitudes and speeds. Guess they assumed problems couldn't happen there.

3. Airbus failed to provide complete key memorization items in their flight instructions for the A-330, leaving out for the most part, high altitude and high Mach cruise situations.
Someone made these mistakes, not sure it was Airbus in every case - some combination of Airbus, airlines, and EASA, yes. I would note that it was AF (not Airbus) who issuesd a revised UAS procedure awfully quickly after the accident...

And in one sense it is worse than above - someone (AF...) failed to train pilots at all in hand flying at cruise in alt law (and quite possibly in any law). Between SOPs and RVSM rules etc., it appears todays line pilots also get no experience of hand flying in cruise either.

Result is that if A/P drops out for any reason (and on any type) in cruise, pilot is handed an a/c he has quite possibly never actually flown at this speed or altitude. Throw in the event happening at night middle of ocean, middle of bad weather, and the result isn't that suprising. Between mfr, airilines, and regulator, no one thought this lack of training / experience was a bad idea, or at least no one did anyting about it.



As in the role of leader, Airbus must not have/didn't push the issue hard enough with EADS, or so it seems or didn't view correctly the critical nature of pitot icing at high altitude and high Mach.
[...]
What did they advise EADS to do? Airbus has the lead here, not EASA. Did EASA respond appropriately based on Airbus' strong recommendations? Did Airbus have a strong recommendation?
We'll find out on that - maybe. Currently the director of EASA is refusing to appear before the judge to answer questions on EASAs role in this event.... [ and yes I am entirely sure that this is for the best of principled reasons and not because there is something to hide :E ]


Now Airbus knew the AOA was a critical key component to assure safe flight, but where was the indicator to know what it was and where it was going?
Agreed [for what my opinion is worth, which is zero] - stall warning / stick shaker is way too crude, no difference between "you are nearly stalled" and "you are stalled by 30+ degrees".

Just to be clear on the Airbus role though - the indicator exists, the space on the panel exists, the airline deleted it as an option when ordering.

The final report on this accident may well say that the AOA indicator should/must be there - the sad thing is that it won't (by a long way) be the first accident report to say that, and it will probably be ignored, again.
The operational side of the industry have decided airline pilots don't need AOA, and/or they don't want the expense of training on it.

[jcjeant]

Hi,

but it becomes a whole different ball game when you lose an airframe and everyone in it. And once again the saying is true:
It is too late to squeeze the buttocks when, **** in the sheets
The sheets of Air Caraibe are clean ...

[infrequentflyer789]

Where have you seen those large chunks of 330/340 on the ground when finally EASA woke up in AUG 2009, after the war, to implement the AD 2009-0195 (http://ad.easa.europa.eu/ad/2009-0195) for pitot probes replacement ?

Yep, have to say I'm with you on that one. The biggest problem with replaceing them turned out to be actually getting enough (decent) pitots out of the supply chain.

Since that takes "too difficult" out of the usual suspects for procrastination, it was most likely "too expensive"... as ever. :(

[DozyWannabe]

I almost agree - from an engineering perspective the gradual degradation makes sense (and Boeing must have htought so too as theirs is practically the same), but if pilots aren't trained in all the modes, they might as well be labelled "crash mode".

I still don't see what's so complex about Normal Law = protected versus other laws = not protected though, which is in reality the only factor that matters at a fundamental level to the pilot.

All you really need to remember is that if you're not in Normal Law you have to be as careful with your bank and pitch angles as you would be in a conventional (unprotected) aircraft. The protections are what allow FBW Airbii to perform some pretty wild maneouvres at airshows, but even if you hand-fly the line in Normal Law it's unlikely you'll ever see the protections kicking in, because the trigger parameters for those protections are considerably beyond anything you'd normally do with paying SLF down the back.

And in one sense it is worse than above - someone (AF...) failed to train pilots at all in hand flying at cruise in alt law (and quite possibly in any law). Between SOPs and RVSM rules etc., it appears todays line pilots also get no experience of hand flying in cruise either.

Result is that if A/P drops out for any reason (and on any type) in cruise, pilot is handed an a/c he has quite possibly never actually flown at this speed or altitude. Throw in the event happening at night middle of ocean, middle of bad weather, and the result isn't that suprising. Between mfr, airilines, and regulator, no one thought this lack of training / experience was a bad idea, or at least no one did anyting about it


This is my primary bone of contention - without this factor the rest of the theorising is somewhat moot.

Saying that this was the eventual result of an insidious industry-wide pattern of laxity and procrastination is not "protecting Airbus".

Agreed [for what my opinion is worth, which is zero] - stall warning / stick shaker is way too crude, no difference between "you are nearly stalled" and "you are stalled by 30+ degrees".

Maybe so, but was it not reasonable to assume that by having a warning several degrees of AoA before the stall that a properly trained crewwould do something about it at that stage?


The biggest problem with replaceing them turned out to be actually getting enough (decent) pitots out of the supply chain.

Now I didn't know that - have you got a source for that just so I've got it on file?

Since that takes "too difficult" out of the usual suspects for procrastination, it was most likely "too expensive"... as ever. :(

Well - possibly, but it raises the spectre of something else that happens in mass production. Ultimately you get the contractors to bid and the ones with the best chance of fulfilling the contract at the required price will get it. If Goodrich could not provide the yields (presuming they were making them as fast as they could) then throwing money at them couldn't get them to make the things faster, so it looks like the Thales AB probes were borne out of necessity. Even if Airbus and EASA said "Replace these now" - if Goodrich couldn't supply them then the replacement work would have been slowed down anyway.

It does rather beg the question of how they worked the AD after the accident though (unless the AD was simply a political fudge to make it look like something was being done, while the replacement programme played out as it did before).

[ChristiaanJ]

Dozy, et al.,

What, in the end, are the differences between the Thales (AA and AB) and Goodrich probes?

AFAIK, all of them are still being qualified/certified against an obsolete standard, and so far I still have NOT seen any 'news' about the standard itself actually having been updated/improved, to take into account the environment that AF447 encountered.

I have the impression that too many people here prefer to 'blame' the UAS events and the pitots, instead of thinking the issue through.

Why weren't the standards changed, after the first UAS incidents due to hi-alt pitot tube icing occurred? Whose responsability was that?

[DozyWannabe]

AFAIK, all of them are still being qualified/certified against an obsolete standard, and so far I still have NOT seen any 'news' about the standard itself actually having been updated/improved, to take into account the environment that AF447 encountered.

The issue is one of all engineering being a compromise to some degree - there is no such thing as a 100% reliable way to measure airspeed in all conditions (in fact one could argue that there is no 100% reliable way to do anything). Being mechanically very simple in principle, along with the fact that there have only been two fairly recent fatal accidents on the line involving failure of the pitot system - and only one where the design of the pitot tube itself is suspect - I'd wager a guess that it is simply the most reliable of the alternatives on offer.

Airbus's response to when the pitot system does fail is the BUSS module, but the way the BUSS calculates airspeed is more complex than that of the pitot system and as such it is better suited to a secondary role.

[Lyman]

FWIW.

Fuel Chemistry was never "mysterious", "Heretofore well understood", or lacking for standards.

It was a Straw man, such that RR could redesign a duff Fuel/Oil Heat Exchanger, and re-enter the playing field as though the design was not dangerous.

Qantas32? Same-O. An AD was relaxed, and an engine exploded in passenger carrying flight.

Comet and Skin? 737 Skin? Rudder? Pilots who hear the STALL WARN and PULL?

Any one see a pattern? No, Engineering is not a "compromise".

Spec. Duty cycle, Training, etc. These are compromises. There is no excuse for a Pitot Tube gnarling up at altitude.

IF that is what happened. Most people never learn, and most of those capable of learning are too easily distracted.

[jcjeant]

Hi,

Again news in the press (Le Figaro)

Le Figaro - Flash Actu : Rio-Paris : de nouveaux lments (http://www.lefigaro.fr/flash-actu/2011/10/07/97001-20111007FILWWW00502-rio-paris-de-nouveaux-elements.php)

Google Traduction (http://translate.google.be/translate?sl=fr&tl=en&js=n&prev=_t&hl=fr&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.lefigaro.fr%2Fflash-actu%2F2011%2F10%2F07%2F97001-20111007FILWWW00502-rio-paris-de-nouveaux-elements.php&act=url)

And weird statements from the SNPL (the most important pilots union of Air France)
So for the SNPL .. just after the disconnection of the autopilot .. PF thought that the aircraft began to descend fast enough ... and so he reacted as we know (put the plane in a stall condition by pulling the stick for "regain" cruise altitude ) .....
Which pilot can think of such thing (important altitude loss after sudden disconnection of the autopilot while ... .. a few seconds before the aircraft was flying perfectly stable)
BEA report N°3
2 h 10 min 05 Altitude (ft) 35 024 (PA disconnection)
2 h 10 min 09 Altitude (ft) 34 664 Altitude ISIS (ft) 34 900
And I repeat these comments come from the majority pilots union pilots of Air France !
This gives again a very bad image of these .. "pilots" ? ...
It's no more "esprit de corps" .. it's foolish instead ..

[Lyman]

We have been previously chastened that the altitude discrepancy was "merely" 300 feet, and was the result of a predictable anomaly in the system.

So I won't hold my breath.

Is there more to this story than "Baby pilot kills all". FGS.

Loss of altitude without a commitment to STALL means exactly what the PF kept reporting, "I feel we have some crazy speed." If at a/p drop, his NU was to arrest descent (as he sussed it), and the 'descent' never 'arrested', this easily explains his commitment to overspeed in descent. It explains his deployment of spoilers, and his disregard for the STALL WARN; without comment or interference from his mates, it appears they all bought it.

What sort of STALL hasn't a concomitant drop of the NOSE? If his reliance (ill placed) on altimeter was driving his thoughts, the entire upset takes on a different shape.

I hadn't known the Pilots had written off the BEA. I'll admit to a bit of relief. Witholding important input from an investigation? The BEA??

Mais non, Impossible. Incroyable, n'est-ce pas?

jcjeant: If the reads were real, the descent was approximately 4,500 feet per minute. Substantial.

[GarageYears]

Loss of altitude without a commitment to STALL means exactly what the PF kept reporting, "I feel we have some crazy speed." If at a/p drop, his NU was to arrest descent (as he sussed it), and the 'descent' never 'arrested', this easily explains his commitment to overspeed in descent. It explains his deployment of spoilers, and his disregard for the STALL WARN; without comment or interference from his mates, it appears they all bought it.But fails to explain why TO/GA thrust was selected, no? Where does that fit?

And the Captain restrained second use of the spoilers right?

What of the altitude call outs/VSI?

If you selectively fit the jigsaw pieces together then may be you think you have a picture, but the box is not empty is it?

[DozyWannabe]

And the Captain restrained second use of the spoilers right?

Almost - it was the PNF (senior F/O). Not that we want to go around those houses again, but it looks like he had a better idea of what was going on and unfortunately didn't feel he had the authority to intervene.

[HazelNuts39]

The drop of 300 ft in indicated altitude as a consequence of a drop in the measured total pressure is apparent in AIR CARAIBES memo dated 01-12-2008. I discussed the reason for it in my post on the AF447 thread no.1 (p.193, post #3856, 24 july 2009), and BEA explained it again in para. 1.6.11.6 'Consequences of a drop in the measured total pressure' of their Interim Report No.2 of December 2009.

[Lyman]

GY

Hey. I'm trying to find more pieces, not reject some in favor of a bias. I am looking for reasons to explain certain behaviours? Well, yeah, since the data are thin, and there is evidence that BEA have redacted some evidence for now. Now THAT'S selective, to my way of thinking. I'd be perfectly satisfied if BEA gave you the CVR, let you suss out the deal, and report back.

You, I trust. BEA? Not so much.

TOGA? Not that it's much more than Cruise power, but couldn't he be looking for ways, alternatively, to gain NOSE UP?

We know the NOSE was already up, did he? Not if he rejected the STALL.

Let's don't assume that he was selecting TOGA to recover a STALL he may not have honored? If he was convinced the a/c was descending normally, and one has to allow him that, than TO/GA is a way to force the NOSE UP.

Just because we don't associate spoilers with TOGA doesn't mean it wasn't that way. It was a goofy night, all around. Another thing. What if he saw the TRIM at 13 degrees? With full aft stick, and still entertaining Overspeed, he's thinking the a/c is unresponsive; TOGA as a try?

[Lyman]

Does it not appear to you all that they knew they were descending, but that they thought it was an ordinary (Unstalled) descent? That the Captain rejected spoilers perhaps because he thought they were too fast? That they may not restow correctly on recovery of normal speed? That they never sussed the descent was slow (airspeed), and vertical, rather than horizontal ('normal' assiette), with plenty (too much) airspeed?

Can you see it another way?

At the end, the Captain.... "It cannot be..." Does he just then realize the ship is way nose up? Not Nose down, and (seemingly) 'unresponsive' to Pitch UP commands? They have had no ordinary sense of decel, nor a NOSE DROP, the a/c has been around one g all along, what did they have to sense the a/c's attitude? (That they trusted?) And Clearly, they were unaware of the attitude. How would YOU have known?

"Pull, Pull, Pull...."

Hazelnuts39. Yes, the indicated drop. We know. You know. Did 447 crew Know? Because at uncommanded a/p drop, the ship was descending (for real, though trending NU), rolled right, and presented 336 feet too low.

Two seconds later, a STALL STALL. Some of which were bogus. There was a simultaneous sink, so what does he do? The a/c did NOT climb readily, per BEA, in spite of PF's aft stick. His initial left roll was excessive, so with all this going on, I'm going to go out on a limb and say he............got off to a bit of a bad start. He was never given proper cues to sort that out. Lack of reference(s).

[CONF iture]

Before the crash, you can bet the airlines would have balked.
Why would they have if it can help them to avoid a latent unsafe condition ?

Also, my understanding is, and people with knowledge will correct me, an AD is on the manufacturer’s arms, but a SB is for the airline … ?


ChristiaanJ,
The only thing is that the Goodrich model has proved to be much more resistant to ice crystals than the Thales ones.
Why weren't the standards changed, after the first UAS incidents due to hi-alt pitot tube icing occurred?
As early as 1999 the German BFU had recommended to modify the certification criteria for the pitot probes. But the EASA has been waiting AFTER the accident to go ahead.
Also Air Caraibes did an excellent job to report their events to Airbus. What did Airbus ?
Nothing.

Excellent presentation : AF 447 : l'accident expliqué selon le modèle de REASON (http://henrimarnetcornus.20minutes-blogs.fr/archive/2011/10/05/af-447-l-accident-explique-selon-le-mo.html)

[jcjeant]

Hi,

This month .. a new book from the author J.P Otelli

Livre : Erreurs de pilotage, Tome 5. Jean-Pierre Otelli - 9791090465039 (http://www.decitre.fr/livres/Erreurs-de-pilotage.aspx/9791090465039)

After the success of the first four volumes, Jean-Pierre Otelli continues the series of pilot error.
The evolution of the news will certainly include a detailed explanation of one of the most mysterious crash of recent years: the crash of Air France 447 Rio / Paris. This accident and the mystery that has surrounded aroused immense excitement in France as well as in Brazil. For nearly two years the world tried to understand what happened to Flight 447. Many hypotheses have been raised.
Most were based on a failure of the Pitot probes of the Airbus, but few were those who thought it was an ordinary pilot error. Only when the flight recorders were eventually recovered by 3900 m deep that the truth emerged. Beyond the issues facing modern aviation safety and pilot training, the crash of Flight Rio / Paris remains a textbook case in the annals of aviation.From what I read .. Otelli tell he had access (or had intelligence) of not yet public parts of the CVR .. and can affirm that the crash was the consequence of pilot error .. no more .. no less ...

Wall Photos | Facebook (http://www.facebook.com/photo.php?fbid=198950073509363&set=a.134687563268948.27514.121531411251230&type=1&ref=nf)

Pilot error Volume 5 - INFO 5: RIO-PARIS: you can read an exclusive complete transcript of the conversations of pilots (CVR).
Available October 3 Altipresse (http://www.altipresse.com/) on our website and in bookstores October 13.

[Machinbird]

The crew of AF447 briefly had the Speed brakes out.
If fast, they should have been thrown forward. They obviously felt next to nothing.
Their thoughts were unable to focus on this deviation from expectations. They were clearly not in problem solving mode.:sad:

[Lyman]

Have you found exactly when and for how long the spoilers were up?

I repeat, from the outset, the a/c may have misbehaved, at least in the judgment of the flight crew. It appears the PF wanted NOSE UP for the duration, and didn't 'get' it. Initially the a/c did need NU, and it did not respond to ss until PITCH reached 10 degrees (and this without the THS). Were the spoilers active in auto? If their deployment did not cause decel, couldn't PF have concluded they were not working?

So with initial pull, the a/c did not trim itself to follow the pilot's stick, how do we explain that? He knew to control the roll (the roll impetus is irrelevant) and he has to have been using the FD w/o external cues. So was the Pitch cueing working? Both pilots were fixated on Roll? To the exclusion of noticing the NU? It is not sufficient to use partial data to conclude these things. Especially the "thoughts" part. That recorder has not been invented yet. A poor resource would be CVR, and that is being parsed to political ends.

I'd rather remain frustrated without sufficient data than to more or less blindly put their final four minutes in stone.

You propose to know his thoughts. I'm trying to find something that worked for them. That would be a better starting place than to join him later at spoilers with a preconceived conclusion. What we see are results of data that was unavailable to the crew, for the most part. Assuming this crew could follow along with data derived from recorders is nonsense.

[DozyWannabe]

Why would they have if it can help them to avoid a latent unsafe condition ?

Also, my understanding is, and people with knowledge will correct me, an AD is on the manufacturer’s arms, but a SB is for the airline … ?

I presume that barb is directed at me, which is a bit of a shame - because I try not to insult you directly, even if I do think your choice of heroes is misguided.

The question is not one of who is paying for the repairs - though it could be a factor in the decision. The problem is this - even if an AD did make Airbus pay for the repairs as opposed to the airlines, the airlines still lose money because an aircraft on the ground is not generating revenue. Airbus are, I'm sure, business-savvy enough to factor in a budget for unscheduled repairs and in the grand scheme of things it would be a cost of a few million dollars to a multi billion-dollar company - one that was in relatively rude health in 2008 and 2009.

With airlines it is less clear-cut and some have more of a margin available to them than others - however even a major flag-carrier like AF will not have the margins available to them that Airbus do. I'd like someone who knows to confirm, but at a guess I'd say that AF stood to lose more in revenue from the aircraft being on the ground in MX than the cost of the repairs to their fleet.

To my mind the issue of pitot replacement will be a factor in the findings and Airbus will have to take their share of the knocks there. What bothers me though is that AF's procedures allowed for two members of a crew who had little to no experience in manually handling the aircraft at high altitude to occupy the LH and RH seats at a time when the whole industry knew that frozen pitot tubes could lead to the aircraft being handed back to the crew at cruise level.

[RR_NDB]

I have the impression that too many people here prefer to 'blame' the UAS events and the pitots, instead of thinking the issue through. (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-58.html#post6738603)

Important issue to be discussed. Simple devices with so much (Systemic) responsibility, that failed in AF447? and triggered the sequence of events.

1) System redundancy techniques are good for random (time) element failures.
2) F-GZCP Pitot's failed? They had just a "brief thermal glitch".
3) Pratically SIMULTANEOUSLY.

"Who" failed?

IMO, this is an complete ABSURD! And ongoing?, as CJ ask. (http://www.pprune.org/6738603-post1144.html)

[infrequentflyer789]

Loss of altitude without a commitment to STALL means exactly what the PF kept reporting, "I feel we have some crazy speed." If at a/p drop, his NU was to arrest descent (as he sussed it), and the 'descent' never 'arrested', this easily explains his commitment to overspeed in descent.


Oh come on. The "descent" at A/P drop was not only arrested it was turned into stupidly rapid climb at 10-15deg nose up. And if PF didn't grasp that from the instruments, PNF also told him, at least twice I think.

The later descent starts from nose up and stall warning sounding, and the nose never goes down - how could that not be a stall ? When later the nose does go suddenly down (as the control surfaces hit the stops) PF carries on pulling hard back. Had it dropped rapidly at the stall, surely he would h\ve done exactly the same as a minute later - pulled back.

[Lyman]

Infrequentflyer789

NO. The a/c did not respond immediately to PF's back stick, read the report. The a/c did not start upward until the PITCH UP reached ten degrees, read the report. Hence my comment that the THS seemed unavailable from a/p drop, until just prior to the STALL. It also counters the myth that he pulled the a/c up immediately, HE DID NOT. The report shows a pilot with measured pull, and interrupted, waiting for response.

The a/c was raising her nose as an artifact of the last gasp of the a/p. She did not climb, not initially. And we don't know if she had NU at that point or no.

We also rely on the pilot's words themselves; he susses overspeed, and likely did until just before impact, when all three wanted to pull. Was that a mistake? Yes, but it was not "Blindly pulling into a STALL". The recorders make fools of us all, unless they get overwritten, after a safe landing.

You are putting motives and methods into this that do not exist. They had been dealt a hand that we have analysed without restraint. They had several cues that lied, that caused on their own the circumstyances that led to the crash.

Their is NO determination of Iced Pitots. It is a guess, for all we know it may have been wind shear that bolluxed up ADRS. And that is a reason for TOGA and high Pitch, in its own right.

I appreciate your response.

[infrequentflyer789]

From what I read .. Otelli tell he had access (or had intelligence) of not yet public parts of the CVR .. and can affirm that the crash was the consequence of pilot error .. no more .. no less ...

I kind of hope he's just a liar - there's been enough leaks already and there are almost certainly bits of the CVR that should never be public.

On the other hand, perhaps it would dissaude those who keep insisting the investigation is hiding things / covering up - when it can't be, because it's already been shown to leak like a sieve...

[Machinbird]

Lyman
Have you found exactly when and for how long the spoilers were up.

From the BEA 3rd Interim report:

2 h 12 min 04 TO 2 h 12 min 07, The airbrakes are controlled and deployed, and the PF said,”I have the impression that we have some crazy speed no what do you think?”
2 h 12 min 07 at 29,736 feet altitude, the PNF said, “No above all don’t extend (the)”



As I read this, the adrenalin flowing from each of the guys sitting in the cockpit was enough to override their ability to evaluate their surroundings.
3 seconds of speed brake is enough to feel deceleration if you have speed. They felt next to nothing at the AOA and speed that they were actually at. They would have had to sense a non-event in order to realize its significance, i.e. NO deceleration-Why?

[CONF iture]

I presume that barb is directed at me, which is a bit of a shame - because I try not to insult you directly, even if I do think your choice of heroes is misguided.
Never been a secret how I evaluate your behavior : Write a lot as if you have the knowledge but proved repeatedly that you don't necessarily have, IMO of course.
Who are my heroes ? You ?

I presume that if an AD had to ground a fleet, the manufacturer would have to share more that the only cost of the repair.

What bothers me though is that AF's procedures allowed for two members of a crew who had little to no experience in manually handling the aircraft at high altitude to occupy the LH and RH seats at a time when the whole industry knew that frozen pitot tubes could lead to the aircraft being handed back to the crew at cruise level.
What bothers me is that something was wrong in that aircraft before anything happened. The crew had to deal with something bizarre ... and the BEA has not said a single word about it.

http://i45.servimg.com/u/f45/11/75/17/84/af447_20.png (http://www.servimg.com/image_preview.php?i=116&u=11751784)

Full data for the families.

[Machinbird]

Confiture, your graph of V/S commanded vs V/S actual is missing time marks. Looks like the selector for V/S was misbehaving. What is the source of this graph?

[Clandestino]

Well done, OK465! Seems I still owe you Saint-Exupery's quote. Oh well...

The machine does not isolate man from the great problems of nature but plunges him more deeply into them Good old Dick Bach's "Steel, aluminum, nuts and bolts" is applicable too.


graph of V/S commanded vs V/S actual is missing time marks2:09:00 to appx 2:10:06
What is the source of this graph? BEA interim 3
The crew had to deal with something bizarre ... and the BEA has not said a single word about it.They haven't issued a final report yet. Hurry up and make your concerns known to them before they settle on the final version. You might just be onto something and if they ignore your wealth of expertize, you can always expand on "How come that records of spurious V/S selections have no correlation whatsoever in aeroplane's behaviour while ALT CRZ mode is engaged" thesis and get master's degree from the Institute of Conspiracy Theories, Department of Aeronautics.

Trust me, I am very familiar with mach and AoA. I also appreciate a design of the fly-by-wire control laws that takes into account of all the aero crapola.I trust you on F-16. Since I have to be blunt: F-16 is unstable fighter, A330 is stable passenger aeroplane. One has wing optimized for maneuver and supersonic flight, the other for high-subsonic cruise. No points for guessing which is which.

Until you have supersonic flow over the entire wing, then the basic AoA works like we expect. Again, some general principles apply for both F-16 and A330 but not each and every. A330 wing starts decreasing its AoAcrit at mere 0.3 Mach - that's why graph on page 20 of interim 3 looks so crooked.

your hero Asseline would not have been alive to lie about the aircraft in the first placeCarefully there! Captain Michel Asseline blurted-out that engine did not responded as required in shell-shocked state. Eventually he settled down and accepted the facts of his fateful flight, as put down by BEA. He does not support any of our "Airbus is soooo complicated and veeeeery dangerous" claiming friends. Also, while they try to appear they are fighting on his behalf, they go great lengths to never explicitly state so and all they offer is series of nudge-nudge-wink-wink-you-know-what-I-mean.

Great shame about Habsheim disaster is that some of us (well, IMHO it's actually most) allow that the smokescreen of technical discussion obscures the real issue: how come that Air france and Mulhouse Aeroclub came to idea that it's just fine to fly planeload of passengers during display flight! Mind you: they were not stupid but somehow they were lead to the point they considered it to be OK. To draw out that thought and decision process into the light would be fitting monument to the three victims.

process will be in 10 or 15 years (St Odile and Concorde style)Now you mention St Odille: it's another tragedy where technical talk has drowned out the HF anaylsis. Most pilot just remember it vas 3300 fpm misselection instead of 3.3 FPA and that's about it. FWIW the crew undershot the final approach track and were well left of it when they hit the mountain. Had they been more concentrated on horizontal navigation (as the report claims) and got established or overshot to the right, they would have missed the mountain. Whether they would realized something was terribly wrong when cloudbreaking above the plain south of Strasbourg or they would have hit the fields instead of forest, anyone's guess is as good as mine.

Airbus failed to provide complete key memorization items in their flight instructions for the A-330, leaving out for the most part, high altitude and high Mach cruise situations.Did not. Airbus procedures were clear, simple and not adhered to. AF FCTM was out of step.

Simply telling the pilots to read the five-color s#!thouse on reflecting and worn-out screens with a multitude of same color digital indicators and FMAs with five windows on three rows with zillions of different abbreviations is, to cite the Borg, futile....Cry me a river about it. Unless you're capable of performing just that, don't go flying, you're gonna hurt yourself and others in the process. It's a tough world outside.

that if A/P drops out for any reason (and on any type) in cruise, pilot is handed an a/c he has quite possibly never actually flown at this speed or altitude.See previous entry.


The a/c did not start upward until the PITCH UP reached ten degreesProve it. Win Nobel for physics. Go down in history as "The man who disproved Bernoulli and everything we thought we knew about flying"

I presume that if an AD had to ground a fleet, the manufacturer would have to share more that the only cost of the repair.EASA AD 2009-195 had four months compliance period, starting on Sep07 2009. Is it conspiracy? Is it possible that by the time of issue we had 20-odd cases of freezing pitots and going ALTN, some involving Air France, one involving Goodrich pitots, all of them landing uneventfully, bar one so there was no perceived need to hurry? No use in having the right to know without the capability to understand.

this is an complete ABSURD! And ongoing?

Taken completely out of its context, it would be quite useful as the best evaluation of this thread in quite a long time.

[Gretchenfrage]

Originally Posted by gretchenfrage
Simply telling the pilots to read the five-color s#!thouse on reflecting and worn-out screens with a multitude of same color digital indicators and FMAs with five windows on three rows with zillions of different abbreviations is, to cite the Borg, futile....
Cry me a river about it. Unless you're capable of performing just that, don't go flying, you're gonna hurt yourself and others in the process. It's a tough world outside.


You may be right, at least that's what I have done and left the blue side as soon as I could. I never felt on top of these machines and I bet many feel the same but do not admit it.

I feel competent enough on another system now and that's what counts in professional aviation.

You can now lie back and feel safe because one of the subjects who seemingly was not good enough for the wonderbra has left the building. But that does not fix the filling, believe me.

Instead of aping the infantile slogans of the lobby-corner ("love it or leave it"), you might have read a little further and caught what I said as well: That there exists a better solution to the problem and that it might just be a better idea to copy that than shout down those who bring up the problem.

Doing the latter is what happens to a great extent actually and that in turn does not comfort me, because these machines share a great chunk of airspace with me. And my theory is that too many of their jockeys are similarly not as good as you think you are.

[Turbine D]

Clandestino

Quote:
Originally Posted by Turbine D
that if A/P drops out for any reason (and on any type) in cruise, pilot is handed an a/c he has quite possibly never actually flown at this speed or altitude.
See previous entry.

WRONG - Not my quote, you got your "hamsters" mixed up.

Quote:
Originally Posted by Turbine D
Airbus failed to provide complete key memorization items in their flight instructions for the A-330, leaving out for the most part, high altitude and high Mach cruise situations.
Did not. Airbus procedures were clear, simple and not adhered to. AF FCTM was out of step.

I'll stand to be corrected when you show me evidence of AB's high altitude, high Mach cruise situations, such as UAS events, which are clear and simple.

[CONF iture]

They haven't issued a final report yet. Hurry up and make your concerns known to them before they settle on the final version. You might just be onto something and if they ignore your wealth of expertize, you can always expand on "How come that records of spurious V/S selections have no correlation whatsoever in aeroplane's behaviour while ALT CRZ mode is engaged" thesis and get master's degree from the Institute of Conspiracy Theories, Department of Aeronautics.
Captain my Captain how do you positively know ALT CRZ mode was engaged when the trace is nowhere to be seen ?
BEA has that habit to forget to share what could be interesting.

Full data to the families.

Take that sunday off Clandestino and try to find someone ready to demonstrate you a bit of love, this could help to relieve this aggressiveness to us all around.

[Zorin_75]

Full data to the families.
Or would that be full data to self important internet conspiracy theorists?

[ChristiaanJ]

Or would that be full data to self important internet conspiracy theorists?Zorin, drop it.
Neither those conspiracy theorists, nor the families, nor their 'ambulance-chasing' lawyers, have the technical competence to interpret those data correctly.

[Lyman]

Clandestino. BEA report the a/c did not begin to climb until the Pitch was 10 degrees+.

In descent, robust enough to keep the altitude from increasing with 9 degrees PITCH UP, a/c don't climb whilst arresting descent.

They reduce ROD instead, until the rate becomes positive, as per BEA.

WINDSHEAR event on ACARS. TCAS event on ACARS. Repeated descent commands of 5000fpm by the autopilot.

BEA have vacuumed the time period prior to the loss of Autopilot.

Odd. "Baby AUTOPILOT kills all!" ?

[KBPsen]

BEA report the a/c did not begin to climb until the Pitch was 10 degrees+.No they did not. It is a fabrication and repeating it does not make it more true. Nor does fabricating more do anything for credibility. If any remains.

There is a thing known as intellectual dishonesty and a great many things here fits the definition quite accurately.

[Lyman]

KBPsen

FROM BEA

"The aircraft's Angle of Attack increased progressively beyond ten degrees...AND THE AIRCRAFT STARTED TO CLIMB..."

Do you speak, read English?

[KBPsen]

Yes I do, but not selectively.

The BEA probably knew that there would be people who would apply their own selected meaning to anything the BEA would publish. So they also published this.

http://i1135.photobucket.com/albums/m623/kbpsen/Pitch-Climb.jpg

[Lyman]

BEA: "....and the pilot applied NOSE DOWN INPUTS and alternately left and right roll inputs..."

Did they get it wrong?

[Lyman]

The graph shows F/O Pitch commands. The PILOT FLYING was flying from CAPTAIN's seat?

I'll leave it to you to sort why the comments don't jive with the graph. For now.

Know that vertical speed does not represent altitude, or "CLIMB"

[DozyWannabe]

What bothers me is that something was wrong in that aircraft before anything happened. The crew had to deal with something bizarre ... and the BEA has not said a single word about it.

http://i45.servimg.com/u/f45/11/75/17/84/af447_20.png (http://www.servimg.com/image_preview.php?i=116&u=11751784)


Could just as easily be a glitch in the FDR data though - which can have issues with sampling sometimes and after all had spent the best part of three years on the bottom of the ocean. The regularity of the missing data samples suggests a read/write failure rather than the value actually being read.

Even so, I'm sure I remember seeing Airbus pilots post that they don't tend to use V/S select all that often, and in cruise there'd be no reason to use it. If it's not referred to in the final report, write to the BEA and ask for it - it can't hurt.

[Lyman]

At this point in the flight, DOZY, the a/c is in autopilot.

[KBPsen]

The PILOT FLYING was flying from CAPTAIN's seat?After all this you still haven't figured out who was PF? Not that it is surprising.

I'll leave it to you to sort why the comments don't jive with the graph.Only in your mind. How to sort that I have no idea.

Know that vertical speed does not represent altitude, or "CLIMB"The graphs are there for all to see. Perhaps you should start having a look so we can be free for you home baked "facts".

[Lyman]

The graph and comments are self evident, and conflict.

[DozyWannabe]

@KBPsen

Perhaps you'd like to explain the difference between SELECTED and MANAGED mode on the A330's FCU - and at the same time how the use of the word "and" is equally valid for simultaneous events as it is for sequential events - in fact to imply the latter tends to require the phrase "and then".

[Lyman]

Then show where on the graph AoA ten+ is.

[Machinbird]

And having given the hamsterwheel another spin, Clandestino goes off snickering down his sleeve.
Welcome back to the hamsterwheel Clandestino, did you miss your old friends?:}

[mm43]

Originally posted by Lyman - post #1174 (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-59.html#post6741687)

"The aircraft's Angle of Attack increased progressively beyond ten degrees...AND THE AIRCRAFT STARTED TO CLIMB..."Please clean your monocle!:}

The BEA Interim Report No3 actually said,

"The airplane's pitch attitude increased progressively beyond 10 degrees and the plane started to climb."That was in relation to the initial climb, but during the second phase the SW activated at AoA 5.9°, AOAmax was passed at 7.6°, and CLmax 'break' occurred at 9.6°.

This graphic (http://oi55.tinypic.com/vr55aq.jpg) should help.

[Zorin_75]

http://img254.imageshack.us/img254/4839/beap.jpg

[KBPsen]

- and at the same time how the use of the word "and" is equally valid for simultaneous events as it is for sequential events - in fact to imply the latter tends to require the phrase "and then". That such basic concepts and use of language needs explaining boggles the mind, but then I doubt it needs to be.

It is the deliberate misunderstandings and misrepresentations, selective use of data and the mixing of a sliver of fact with handfuls of fiction that needs explaining. If it is even possible.

[CONF iture]

Zorin_75 and ChristiaanJ,

Beside the conspiracy theorists, anything you could bring to the subject (http://www.pprune.org/6740719-post1164.html) ?

[AlphaZuluRomeo]

Captain my Captain how do you positively know ALT CRZ mode was engaged when the trace is nowhere to be seen ?
BEA has that habit to forget to share what could be interesting.
Ahem... BEA's interim #3, §1.11.2 ;)
No trace indeed, but unequivocally written : "Le vol est effectué sur la route prévue en modes ALT CRZ / NAV."
"The flight followed the route envisaged in modes ALT CRZ / NAV."

Take that sunday off Clandestino and try to find someone ready to demonstrate you a bit of love, this could help to relieve this aggressiveness to us all around.
I'm perfectly happy, for myself, with Clandestino's posts. Shall I ask him to marry me? :confused: :p

Joking aside, I also would like to know why the selected V/S varies so much (and so regularly) before AP disconnect. I think (guess) it is a "normal" behavior but would like to have a confirmation by knowledgeable people.

[DozyWannabe]

Joking aside, I also would like to know why the selected V/S varies so much (and so regularly) before AP disconnect. I think (guess) it is a "normal" behavior but would like to have a confirmation by knowledgeable people.

This is an educated guess rather than certain knowledge, but based on what I've learned on the subject of data analysis (which is actually part of my professional remit - lest CONF think otherwise) those negative peaks are at such regular intervals that I suspect that they are unreadable values rather than reflective of the actual setting, as I said here:

http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-59.html#post6741729

Given that it looks like they've used Excel to generate the graphs for the interim report, I know that Excel's default graphing behaviour for unreadable values is to render them as the lowest possible value (in this case -5000).

Now, whether that value would be unreadable due to corruption of the memory chips from damage sustained, whether the memory chips were faulty in the first place, or whether there was a pre-existing fault on the FDR bus that meant that the value was incorrectly read is something I'm not qualified to speculate on.

Ultimately though, if we can make a reasonable assumption - based the BEA's statement that the flight followed the ALT CRZ/NAV mode - that the flight was indeed in that mode up to A/P disconnect, then the V/S setting should not have had any effect as, if I recall correctly, the MANAGED mode does not use V/S as a parameter.

[ChristiaanJ]

Zorin_75 and ChristiaanJ,
Beside the conspiracy theorists, anything you could bring to the subject (http://www.pprune.org/6740719-post1164.html) ?
CONF, I thought the somewhat 'odd' V/S SEL recording had already been solved, either earlier in this thread, or in one of the earlier threads.

[infrequentflyer789]

Infrequentflyer789

NO. The a/c did not respond immediately to PF's back stick, read the report. The a/c did not start upward until the PITCH UP reached ten degrees, read the report.


I have, I guess I just don't see what you see in the traces.

I have been looking at the graphs with expanded timescale - which show the time we are interested in. P29-31 of the report has useful graphs but without gridlines so it is difficult to be precise, P42 is the best for that - it doesn't have pilot input, but we know from P29 that this begins at 02:10:07.

From graph on P42 I reckon at 02:10:07 we have pitch = 2, THS -2.8, VS maybe -300. Then at 02:10:10, pitch = 4, THS -3 (started to move), and VS maybe +300 (ie. started to climb). Pitch 10 degrees is not till a bit after 02:10:16 by which time VS is already +5000.


Hence my comment that the THS seemed unavailable from a/p drop, until just prior to the STALL.
It looks to me to be moving to follow elevator trend, with a delay, a rate limit and a stop, not much more complex than that. At some point I might try and digitize the traces and try and extract the rule, but it looks right. It also matches the sim results (see P41).


It also counters the myth that he pulled the a/c up immediately, HE DID NOT. The report shows a pilot with measured pull, and interrupted, waiting for response.
Page 29 - A/P drops 02:10:05, "I have controls" at 02:10:06, stick goes back 02:10:07, 2secs delay. I don't see the stick going back to pitch neutral awaiting response either.

Further, the response tracks simulation, so the a/c was responding as PF should have expected. If we ascribe his actions to unexpected a/c response, then we are back to the question of why doesn't PF know what to expect from his a/c, are we not ? [and is it PFs fault if he's never actually flown (been allowed to fly) his a/c in cruise ? - no]


Their is NO determination of Iced Pitots. It is a guess, for all we know it may have been wind shear that bolluxed up ADRS. And that is a reason for TOGA and high Pitch, in its own right.
If there's a windshear procedure that calls for 15deg pitch and TOGA in cruise (at max alt) then I would respectfully suggest that it is a recipe for another disaster. No ?

On the pitots, I think I almost agree. There is some evidence (audio ascribed to icing), and there is the experience of all the other flights - but not totally conclusive.

The worrying thing to me is that I can't see anything that connects the PF actions (cause of stall) with pitot failure specifically, or even uAS specifically. If he climbs to arrest a (real or perceived) altitude loss, or inadverdently while focused on roll, then pitot failure is not a required cause, and fixing the pitots will not prevent a recurrence. UAS may make the recovery less likely - but speeds were actually valid again by the time they stalled, and stalling a big jet is big trouble regardless.

If the triggers for the PF climbing his a/c into a stall were only: A/P drop out, Alt Law, and turbulence (maybe), then we have a big problem, because Alt Law / A/P drop could have lots of causes, and is an expected condition at 1 in 10k flight hours (I think). That is more than a little worrying.

[infrequentflyer789]

I'll stand to be corrected when you show me evidence of AB's high altitude, high Mach cruise situations, such as UAS events, which are clear and simple.

AFs procedures at least are clearly confusing since preople here can't agree what they mean even with plenty of time to read them.

But, turning it around slightly, what evidence is there that any procedure was bring used ?

The quoted (confusing) procedures I have seen all have AP & FD OFF as first actions - and this was never done (AP dropped itself, FD remained selected on).

[Turbine D]

Hi
Infrequentflyer789

Not only does AF's procedures seem confusing, AB's procedures don't seem to me to be much clearer. Below is a briefing (2006, may have changed by 2009) as to what to do with an occurrence of UAS. The briefing was to identify new procedures as the airlines were confused with the older procedures. Of particular interest, note how UAS is highly referenced and dealt with during cruise at high altitudes and high speeds.:(

It's not that the crew of AF447 did everything right, it's what they may have been taught or not taught, remembered or not remembered for the situation they found themselves in.

Take a look and tell me what you think.

http://www.iag-inc.com/premium/AirbusUnreliableSpeeds.pdf

[alexd10]

@ #1190 Originally Posted by DozyWannabe

This is an educated guess rather than certain knowledge, but based on what I've learned on the subject of data analysis (which is actually part of my professional remit - lest CONF think otherwise) those negative peaks are at such regular intervals that I suspect that they are unreadable values rather than reflective of the actual setting, as I said here:

AF 447 Thread No. 6 (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-59.html#post6741729)

Given that it looks like they've used Excel to generate the graphs for the interim report, I know that Excel's default graphing behaviour for unreadable values is to render them as the lowest possible value (in this case -5000).

Now, whether that value would be unreadable due to corruption of the memory chips from damage sustained, whether the memory chips were faulty in the first place, or whether there was a pre-existing fault on the FDR bus that meant that the value was incorrectly read is something I'm not qualified to speculate on.



http://img254.imageshack.us/img254/4839/beap.jpg

Your theory seems a little bit forced . As can be seen on the graph the selected VS value drops ceased to occur at the start of the climb, so it’s improbable to be related to post flight memory damages or data corruption.

If indeed are generated by improper value of the data used for graph, the source it’s highly probable to be a soft/process related to the flight.

So, what can be , and relevant or not for a/c behavior?

[rudderrudderrat]

Hi Turbine D,

It seems to me that PF may have simply memorised 3 attitudes and power settings, and forgotten the "Below Thrust Reduction Alt" bit.
Once he had selected TOGA power, then he placed the aircraft at 15 degs pitch and waited.

Dohhh!!!

[jcjeant]

Hi,

A small question about the behavior of the aircraft (A330)
What is the difference at low and high speed for roll control (aileron effectiveness)
I suppose the roll control is more effectiveness ( more sensitive ) at high speed .. ?

[Lyman]

infrequentflyer789

Thanks for a meticulous and thoughtful reply. I quote the initial BEA text when they sought to describe PF's actions at a/p drop. One can fall back on the dual language, made an issue here, but I prefer to place more confidence in the text as translated, to avoid weasel wriggling.

Some thoughts: The PF's actions were initially "Mostly Nose Down, with alternate roll left and right." Nose down is allowed when the bus is intitially dealing with Overspeed, but gradually ND becomes unavailable, and instead, it is replaced by auto NU, adding to Pilot input, if any.

The THS is also unavailable in Overspeed mode, so that explains the "loss" of THS TRIMOUT after the initial .7 degree TRIMUP. So we are left with a climb of robust nature, and little ND, until just at STALL, where the THS, reinvigorated, cycles all the way NU. Is this from "Memory"?

What does the Bus do if it is in Overspeed after identifying and reacting to it, but then speeds are lost?

Keep climbing? What is the nature of the annunciation of Overspeeding?

I notice your discomfort with a connection twixt UAS and the STALL. I share it. I also am not at all convinced the Pitots misbehaved in any way.

Just as the VSIs were reading "pegged" and "true", these probes could have been legit in their sampling, and the computer confused a "discontinuity" in airspeed with "discrepant" readings at each probe. The a/c apparently can react to these discontinuities as if it is discrepancies, instead. What if the initial airmass shear was additive to IAS? Overspeed determination? What if diminishing in IAS? If sudden, as shear is, could the drop have been 60, 80, 100 knots? Could such a drop in IAS have triggered the "zipper" at VS/SELECT prior to loss of autopilot? There was a WINDSHEAR REPORT on the ACARS, as there was also TCAS alarm?

I mention TOGA and 15 degree PITCH UP not to include it as an option at altitude, but to include it in the PF's muscle memory, and training. It is also possible he selected TOGA to attempt to get the NOSE UP, having not realized the NOSE was UP as high as it was already.

For three minutes, the Pilot was seemingly convinced the a/c had "some crazy speed". The PNF was not convinced, but neither was he ready to take the a/c into a Steep NOSE DOWN recovery. When Captain returned, he never seemed convinced either way, and his presence may have been a fatal distraction to the two at the helm.

So it is possible yet to retain an open mind. Demonstrably it is also predictable to judge the pilots incompetent in the court of easy chair PPRuNe jurisprudence.

[jimjim1]

Re-posted by someone:-

Originally Posted by Lyman

NO. The a/c did not respond immediately to PF's back stick, read the report. The a/c did not start upward until the PITCH UP reached ten degrees, read the report.


OK. I give in. Aerodynamics had no part in this incident:-

It was:-

The Hand of God.

Or perhaps you might prefer - A Hand Of God? Since; He has presumably more than one?

[infrequentflyer789]

It's not that the crew of AF447 did everything right, it's what they may have been taught or not taught, remembered or not remembered for the situation they found themselves in.

Take a look and tell me what you think.

http://www.iag-inc.com/premium/AirbusUnreliableSpeeds.pdf

Agree with that, and for what my opinion is worth (not a pilot, but I know, or used to, a bit about building stuff that flies) it still looks confusing. And it has no examples for cruise (as you say).

"If safe conduct of the flight is affected" is a critical decision point (memory items vs. level-off) yet seems to me to be vague and not defined anywhere. Plus all those nice big graphics of the horizon at 15deg pitch up, and toga...

Does "safe conduct affected" just mean "if no danger of terrain impact" ?

If I immediately have problems controlling roll, is safe conduct affected and should I therefore apply the pitch memory items ?

If in RVSM airspace and I'm struggling to level off, is safe conduct affected and should I therefore go to pitch up :\ ??? [ mind you I should be getting out of RVSM anyway without an A/P ?]

If different pilots on here have different answers, then yes, it's all dangerously unclear.


I'm still not sure 447 ties with any of the procedures though. If they were going for the memory items, and recalled the wrong pitch/power, then FD should have been turned off (in, I think, all versions) - and it wasn't.

On the other hand, if they were going for "level off and troubleshoot"... where does the climb come from ?

It could be misapplied proceudre, it could be inadvertent - I think PNF's comments lean towards the latter, but not conclusive.

What might clinch it woudl be the details of the rumoured (posted on here) AF sim tests shortly after the accident. If most of their crews crashed when faced with the scenario on the sim, then something systematic is wrong at AF and not (only) with the guys on the night. If we knew why they crashed in the tests, then we might be much clearer about why 447 climbed.

I wonder if that info (assuming we believe the rumours) will ever see the light of day, or will AF manage to bury it ?

[infrequentflyer789]

infrequentflyer789

Thanks for a meticulous and thoughtful reply. I quote the initial BEA text when they sought to describe PF's actions at a/p drop. One can fall back on the dual language, made an issue here, but I prefer to place more confidence in the text as translated, to avoid weasel wriggling.


Me, I'll go for numbers every time (blame it on engineering or software background, take your pick). Text has been written by a frenchman, edited by a lawyer and translated by a linguist - the numbers have far less room to wriggle.

As to overspeed, it could have been - but I don't think it was. Overspeed is shown in the trace on P111, and doesn't trigger in the time region shown, which includes the A/P drop.

Also, PF pitch actions were NU first (see same page, below the line is stick-back, above is forward) - whatever the text might say :)


I notice your discomfort with a connection twixt UAS and the STALL. I share it. I also am not at all convinced the Pitots misbehaved in any way.
I think they probably did, but my concern is more that beyond causing A/P drop and Alt Law, pitot failure may have no bearing on what happened. Which means that any other failure leading to alt law could lead to the same result - and fixing the pitots is a convenient scapegoat that leaves larger problems unaddressed.


So it is possible yet to retain an open mind. Demonstrably it is also predictable to judge the pilots incompetent in the court of easy chair PPRuNe jurisprudence.I judge them not (or try not to) - and am not qualified to do so anyway. I try to understand their actions from a user-interface / controls / human-factors perspective, and I await the human factors report with interest.

If I have come to any judgement so far, it is that there were major systemic operational failures that put this crew up there (along with other AF crews if the sim test rumours are true) unprepared to cope with this scenario. And it was a known scenario, precisely known, but clearly not assessed - until after the crash. To quote AF (from Press Releases (http://alphasite.airfrance.com/flight-air-france-447-rio-de-janeiro-paris-charles-de-gaulle/press-releases/?L=1#communique2651) ):Starting in May 2008 Air France experienced incidents involving a loss of airspeed data in flight, in cruise phase on A340s and A330s.But did they train, or even assess, their A330/40 crews to handle a loss of airspeed in cruise ? It would appear not (according to the BEA).

[infrequentflyer789]

Your theory seems a little bit forced . As can be seen on the graph the selected VS value drops ceased to occur at the start of the climb, so it’s improbable to be related to post flight memory damages or data corruption.

If indeed are generated by improper value of the data used for graph, the source it’s highly probable to be a soft/process related to the flight.

So, what can be , and relevant or not for a/c behavior?

Was discussed in several posts some time ago, e.g. http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a-79.html#post6621079 and http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a-75.html#post6618515 and http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a-79.html#post6621079

[infrequentflyer789]

Originally Posted by infrequentflyer789 http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/buttons/viewpost.gif (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-58.html#post6738342)
The biggest problem with replaceing them turned out to be actually getting enough (decent) pitots out of the supply chain.
Now I didn't know that - have you got a source for that just so I've got it on file?

One reference point is that the ADs allowed for replacing only two out of three probes with Goodrich initially, leaving one Thales.

Didn't find my original remembered source, but did find others including this:
EASA and FAA Airbus Pitot Requirements (http://www.aviationweek.com/aw/jsp_includes/articlePrint.jsp?storyID=news/Pitot9099.xml&headLine=EASA%20and%20FAA%20Airbus%20Pitot%20Requirements)12 0-day compliance time. The time was necessary to accommodate a "short-term" problem with the availability of replacement parts "A shorter compliance time might have resulted in the unnecessary removal of airplanes from service pending delivery of replacement parts," FAA said.
Which probably means everyone was right in that argument - could have grounded planes but didn't because risks were assessed and timescales were managed.

[Zorin_75]

whatever the text might say

Regardless of what a certain person will make up, the text is pretty unambiguous in this matter. Just DFTT.

From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS).

[CONF iture]

CONF, I thought the somewhat 'odd' V/S SEL recording had already been solved, either earlier in this thread, or in one of the earlier threads.
Solved, not, discussed at most as just reminded by infrequentflyer789 here (http://www.pprune.org/6746019-post1202.html).
Diagnostic also kindly sent me some references of interest, but more related to the spiky traces phenomena in general. here (http://www.pprune.org/6617993-post1476.html) and here (http://www.pprune.org/6618029-post1480.html).

I share your analysis (http://www.pprune.org/6744496-post1195.html) alexd10.

Ahem... BEA's interim #3, §1.11.2
No trace indeed, but unequivocally written : "Le vol est effectué sur la route prévue en modes ALT CRZ / NAV."
"The flight followed the route envisaged in modes ALT CRZ / NAV."
IMO this has to be seen as a general comment only. As a matter of fact, the flight was not proceeding in NAV anymore but in HDG.

The FD/AP VERTICAL MODE is a critical parameter for the all event, after, but also before the AP disconnect.
BEA ... where is the trace ?

[MFgeo]

To me, there is a much bigger issue than the "sawtooth" trace of selected vertical speed values prior to 2:10:06 (in reference to the graph in posts #1186 and #1195) -- WHY is the selected vertical speed shown as being constant in those graphs after 2:10:42? If what the PF saw on the VSI during that period was a constant, slightly positive value, completely unresponsive to his pitch inputs, it seems likely that he would conclude that the VSI reading was erroneous.

[jcjeant]

Hi,

If I immediately have problems controlling roll, is safe conduct affected and should I therefore apply the pitch memory items ?

I asked before

Hi,

A small question about the behavior of the aircraft (A330)
What is the difference at low and high speed for roll control (aileron effectiveness)
I suppose the roll control is more effectiveness ( more sensitive ) at high speed .. ?


And no answer ..
I asked this because in the BEA report N°3 the PF tell " seem's we have a crazy speed"
If the PF know how react the A330 to the roll command ( he give many .. reference PF SS mayonnaise graph) he must also know if it was high or low speed ...
Logic ?

[rudderrudderrat]

Hi jcjeant,

99.99% of the PF's manual flying experience will have been in Normal Law, where stick deflection controls a roll rate independent of air speed. When he was faced with ALT Law, he had direct control of the ailerons. You get full deflection of the ailerons with full side stick - independent of the airspeed. The roll rate at high Altitude is very rapid, I've never experienced this this for real - but I am reliably informed that it is "very twitchy".

PF seems to have been struggling to maintain wings level whilst he was over controlling. Whether he was flying fast or slow could not be part of his evaluation - because he probably had no previous experience of ALT Law at high FLs to base his judgement.

[HazelNuts39]

Hi jcjeant,
When the PF made that remark, the real airspeed was about 125 kCAS: BEA Interim Report no.3, p.76: At 2 h 12 min 04, the PF said that he thought that they were in an overspeed situation, perhaps because a strong aerodynamic noise dominated in the cockpit.

[AlphaZuluRomeo]

As a matter of fact, the flight was not proceeding in NAV anymore but in HDG.
Yes, and that was reported. I assume: no change reported, then no change occured in vertical mode. You assume differently, that's your call. :)
Let's hope for more traces in the final report.

WHY is the selected vertical speed shown as being constant in those graphs after 2:10:42?
It's constant... for some time... but changed again at ~02:12:50
If what the PF saw on the VSI during that period was a constant, slightly positive value, completely unresponsive to his pitch inputs, it seems likely that he would conclude that the VSI reading was erroneous.
:confused: :confused:
Didn't you mistake selected vertical speed (shown on the MCP) and the current vertical speed (shown on the VSI) here?

[ChristiaanJ]

CONF,

I admit to being baffled by the SEL'D VS trace.
The 'zipper' before the AP disconnect looks like an FDR or postprocessing graph software artefact (as suggested), but why does it jump to +5000ft/min shortly after the disconnect, and then drop abruptly back to approx. zero?

I seem to remember somebody saying earlier that it was not the 'raw' MCP setting, but an 'intermediate' parameter.

Isn't it a red herring, if the AP/FD was in ALT CRZ mode?

I'm not 'au fait' enough with the Airbus FCS.

[Lyman]

Hazelnuts39. It would be interesting to imagine a wind tunnel with the forward ten metres of A330 fuselage mounted level and subjected to 200knots of airstream impacting the belly at 35 degrees AoA.

PF makes his comment, and it was discussed at length, re: motive, CRM, etc. Clearly, at least one airman was baffled by the noise.

A discussion of the zipper trace would be interesting. An understanding of vertical speeds, commands, and events that had an effect on autopilot would be progress. Thus far, no possibilities are broached, and I for one would be grateful if some one would take it on.

A novice' question might be: the VS select 5,000fpm UP just post a/p drop; is that related to the ensuing climb? Because that would mesh with Pilot's inputs to produce 7,000fpm.

Is there evidence of the absence of the a/c having a role in the climb? It would be necessary prior to conclusion that the PF acted alone.

[ChristiaanJ]

Hazelnuts39. It would be interesting to imagine a wind tunnel with the forward ten metres of A330 fuselage mounted level and subjected to 200knots of airstream impacting the belly at 35 degrees AoA.Thanks, Lyman, for confirming you do not have the slightest notion of aeronautical engineering...

Give it a break, mate... you're trying to play way outside your league.

[HazelNuts39]

It would be interesting to imagine a wind tunnel with the forward ten metres of A330 fuselage mounted level and subjected to 200knots of airstream impacting the belly at 35 degrees AoA.The airstream in windtunnels is horizontal (except in spin tunnels where it is vertical). You would need a relatively small airplane model to mount it at 35 degrees AoA without getting too close to the tunnel walls. What would you be interested in? I would be interested in the pressure near the static port, and in the pitching moment at various angles of elevator and THS. I take it that the noise registered on the CVR is generated by the flow separation on the wing. And why 200 kt? The airplane wasn't stalled until the speed was much less.

Though I'm curious about the cause of the 'zipper trace', I don't see any effect of it on the airplane. As the AB simulation shows, the airplane behavior is entirely consistent with the SS control input. There is no delay in the response in pitch attitude.

[Lyman]

HN39. "It would be interesting to imagine....." 200 knots? At 15,000fpm down, and 60 knots forward....... I am interested in what might be considered the type and level of the acoustic environment in the cockpit.

Chris:

I am less embarrassed by my apparent lack of Ae, than I would be to own your lack of imagination.

[Clandestino]

WRONG - Not my quote, you got your "hamsters" mixed up.

My apologies, sir, I indeed wrongly attributed the quote to you. Sorry. I'll do my best not to let it happen again.

I'll stand to be corrected when you show me evidence of AB's high altitude, high Mach cruise situations, such as UAS events, which are clear and simple.

Interim 3, page 59. Oh, wait a minute...


Not only does AF's procedures seem confusing, AB's procedures don't seem to me to be much clearer.

So you know about them!

I have some bad news for you, sir. If you think procedures are confusing as you sit comfortably in front of your computer screen, there is no chance in Detroit you'll be able to recognize the one to be applied at 0400 AM at FL 330 when hell breaks loose. You can't be an Airbus pilot unless you radically improve your airmanship. As Boeing procedures, despite indignant and unsubstantiated cries they're otherwise, are not radically different from AB's, you probably won't cut it right now as Boeing pilot either. Or Embraer pilot. Or Tupolev pilot. Or any airliner pilot.

Good news is: given solid & undamaged head mounted computer, clean bill of health, good hand to eye coordination, lots of effort and determination and considerable time, one can become a pilot.

AFs procedures at least are clearly confusing since preople here can't agree what they mean even with plenty of time to read them.

Good thing they were designed with pilots in mind, not PPRuNers.

It seems to me that PF may have simply memorised 3 attitudes and power settings, and forgotten the "Below Thrust Reduction Alt" bit.
Once he had selected TOGA power, then he placed the aircraft at 15 degs pitch and waited.

Flying aeroplanes is tough job! One of the requirements thereof is to promptly tell the difference between "below acceleration altitude (tipically 1500 ft above ground level) and "above FL100". Not for easily confused.


That there exists a better solution to the problem and that it might just be a better idea to copy that than shout down those who bring up the problem.

Do you have a slightest idea what was the topic you brought on and we were discussing?

It was flight instruments (ATA 31) and autoflight (ATA 22), not FBW (ATA 27)!

Regarding EFIS/AP/FD there is not much difference between Airbus and the rest of the world. Heck, Piper Cheyenne has more FD buttons and not much less FD modes than FBW Airbi. I don't see that allegedly better solution applied anywhere!

Nose down is allowed when the bus is initially dealing with Overspeed

Not applicable as aeroplane was in ALTN law. No overspeed protection there.

I notice your discomfort with a connection twixt UAS and the STALL

There shouldn't be any connection. If it weren't for utterly paradoxical pilots' reaction, that is.

Does "safe conduct affected" just mean "if no danger of terrain impact" ?

No. It's a tough life in the cockpit, when one has to know all the time what is safe and what unsafe. This game is not for faint hearted. Or feeble minded.


If most of their crews crashed when faced with the scenario on the sim, then something systematic is wrong at AF and not (only) with the guys on the night. If we knew why they crashed in the tests, then we might be much clearer about why 447 climbed.

You might want to have a look at interim2, pages 100-103. 37 330/340 crews faced with the same problems as AF447's did. In real life, not sim. All survived. Surprise, surprise.

how do you positively know ALT CRZ mode was engaged when the trace is nowhere to be seen ?
(...)
The FD/AP VERTICAL MODE is a critical parameter for the all event, after, but also before the AP disconnect.
BEA ... where is the trace ?

I have never used anything but ALT CRZ in cruise, never heard of anyone who didn't, interim 3 is pretty clear on it and anyway I don't think that "Superiority of using V/S mode in cruise instead of ALT CRZ on A330 series aroplanes" thesis is going to get anyone that coveted PhD, no matter how original the research will turn out to be.

It's critical... just how? As long as AP is engaged, it's straight and level. When it drops out, aeroplane behaviour is consistent with the sidestick input in ALT law. Do you dispute that?

[Lyman]

Clandestino. Can you school me on Overspeed, and A/P reaction? Also, what of a sudden loss of speed (Indicated) that would require a/p remediation? How does the autopilot control these deviations from "straight and level"?

If the computer senses and controls A/S with Pitch, it obviously stays in NORMAL LAW for the duration. "there is no Overspeed Protection in ALT LAW." If Overspeed prot had latched, and the IAS were lost, what would be the a/c's reaction? What does the a/c do with "Overlap".

IOW, with the a/p's manouvering limits, what occurs to the "gradual" diminution of Control LAW? Say the a/c was in a protection, and the a/p limited out, what then? If in NORMAL LAW in OVERSPEED protection, what does the a/c do with a conflict? How long would NORMAL LAW obtain, after UAS had tripped the a/p?

[HazelNuts39]

Lyman,
Except where airspeeds are erroneous due to either blockage of pitots or due to extreme AoA causing large errors in the pitot and static pressures, they correlate closely with groundspeed derived from IRS and GPS. That correlation excludes sudden large loss or increase of airspeed with meteorological origin.

[Diagnostic]

@Clandestino:

You might want to have a look at interim2, pages 100-103. 37 330/340 crews faced with the same problems as AF447's did. In real life, not sim. All survived. Surprise, surprise.

With respect, sir, you (and the BEA) do not know that those "37" other crews faced "the same" problems as AF447 (how many of the multiple elements of each situation are you comparing?). Of course those events listed in interim 2 appendix 7 are believed to be icing events of 2 or more pitot probes, but that is the only similarity which the BEA state. As the BEA explain in interim report 2, there is insufficient data gathered for most of the other events, for detailed examination. Only 13 events had enough information for such examination (see interim report 2, section 1.16.3, PDF page 51 onwards).

As I said to you on 31 Aug (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-34.html#post6673738) the behaviour of some other crews where such detail is known, is not without fault either - so the degree to which AF447 is an exception is far from black & white.

Of course AF447 are the only crew to crash, but that is a very superficial view, IMHO. Look deeper into section 1.16.3 which I mention above, and several similarities with (incorrect) crew behaviour are seen amongst other crews too.

[ChristiaanJ]

Chris:
I am less embarrassed by my apparent lack of Ae, than I would be to own your lack of imagination.Let's not get into a reciprocal slanging match (again?) but with more than 30 years in "Ae", I think I know the difference between unfounded imagination and knowledge better than you do, it seems.

[Turbine D]

Clandestino

I accept your apology regarding the "hamster" mix up.

As to the rest of your remarks directed towards me, well, normally I would ask some questions regarding the small bits of technical input you mentioned. However, I don't think you are the right person to ask anything of, given your mental disposition.

I will say, your apparent suffering from cerebral flatulence that you mentioned, could be a problem, a charm school might help, but you should ask your doctor what's right for you.

[Lyman]

Hazelnuts. Hmmm. Groundspeed? GPS? Inertial? I am entertaining transient (brief) discreps. Only as little as 30 knots can cause an ADR problem? Here is what I mean by overlap. Are you saying then that the airspeeds were only erroneous, and can have no basis in reality if their effect was to cause error?

Big airplane, lag to velocity? Besides, if reversing, there is a possibility meteorological challenges can go under the "Radar"? (Discovery).

Chris: I most quickly grant you your observation re: "unfounded" imagination. Imagination, by its nature, is vulnerable to ignorance. If I am ignorant of the platform, I welcome your corrections, no slang intended.

:ok:

[gwillie]

Bloomberg:

Air France Crash Book Shows Pilot Confusion

The first book investigating the Air France 447 crash...
Publishing what he says is the first full transcript of the pilots’ voice recordings, French aviation author Jean-Pierre Otelli describes a scene in the Airbus SAS cockpit that is dominated by confusion, a lack of coordination, and denial among the flight crew as the jet plunged through the night sky toward the ocean surface. Otelli, who specializes in aviation safety, publishes his book “Piloting Error, Volume 5” today.

Air France Crash Book Shows Pilot Confusion - Bloomberg (http://www.bloomberg.com/news/2011-10-12/air-france-crash-book-shows-full-transcript-of-pilot-confusion.html)

[jcjeant]

Documentation

Flight Crew Training Manual Airbus Air France
AFR A330/A340 FLEET PIR-010. P 4/4
FCTM 09 JUL 08
PDF_F_FCTM_AFR_TF_F_EU__20090113_FCTM.pdf (http://www.mediafire.com/?ode8xy6ya4wrsug)

[NARVAL]

quote Rudderat:
Hi jcjeant,

"99.99% of the PF's manual flying experience will have been in Normal Law, where stick deflection controls a roll rate independent of air speed. When he was faced with ALT Law, he had direct control of the ailerons. You get full deflection of the ailerons with full side stick - independent of the airspeed. The roll rate at high Altitude is very rapid, I've never experienced this this for real - but I am reliably informed that it is "very twitchy".

PF seems to have been struggling to maintain wings level whilst he was over controlling. Whether he was flying fast or slow could not be part of his evaluation - because he probably had no previous experience of ALT Law at high FLs to base his judgement. "

Correct as far as alternate law is in play. In normal law, the roll efficiency starts to decrease above Va (250 knots in the A320 family) to protect the airframe and wing structure. That seems little known to pilots, but when you are under 10000 feet at 250 knots as mandatory, you have the best possible roll efficiency for traffic avoidance (relatively high speed with full aileron deflection).

I learnt recently that the autopilot in cruise "trims" the airplane for 0,9g, but of course maintains 1g through elevator position. When you loose the AP, the plane has a natural desire to climb...Not very useful, but sharing what I learn!

[alexd10]

Jean-Pierre Otelli's book: "full transcript of the pilots’ voice recordings" acc to the Bloomberg/autor or " a part of a literal transcription of the Cockpit Voice Recorder" acc. to an inflamed BEA ?
http://www.bea.aero/en/enquetes/flight.af.447/pressrelease13october2011.pdf

Had anyone read it? And found some relevant for accident?

[rudderrudderrat]

Hi Narval,
When you loose the AP, the plane has a natural desire to climb...The only aircraft I know which did that was the L1011 during an Auto Land Approach. (AL selected)
Every other aircraft I've flown, when the AP drops out, remains in trim and continues along the same trajectory. I can confidently report that's true for the A320 series in Normal Law. (If it does what it says on the tin - then it should be the same in ALT LAW also)

[DozyWannabe]

I learnt recently that the autopilot in cruise "trims" the airplane for 0,9g, but of course maintains 1g through elevator position. When you loose the AP, the plane has a natural desire to climb...Not very useful, but sharing what I learn!

Hold up - I remember reading something like that about the A320 (which has a marginal tendency to climb), but also that the same situation is not the case on the A330/340, which hold their trajectory. Is this the same thing we're talking about here?

[AlphaZuluRomeo]

alexd10, the book doesn't contain a "full" transcription.
=> BEA is right to describe it as "a part of a literal transcription of the Cockpit Voice Recorder".

The book is not a "revolution" in my opinion, but come with some indications. Note that the BEA is right when it wrote:
"This transcription mentions personal conversations between the crew members that have no bearing on the event, which shows a lack of respect for the memory of the late crew members."
Indeed, most of the "new" elements of the transcription in the book are more or less personal and/or not related to the flight. :hmm:

But, in the same time, the BEA forgot (?) to publish (or delayed it until the final report?) some parts of the CVR which are, from what I understand, relevant to the flight. The most striking example:
02:11:45.5 (PF) On perd le contrôle de l'avion, là
02:11:46.7 (PNF) On a totalement perdu le contrôle de l'avion... On comprend rien... On a tout tenté...
translation to english, I just tried with google and it's not so good, so here we go for non-french readers:
(PF) We are loosing the control of the aircraft, here
(PNF) We have totally lost the control of the aircraft ... We understand nothing ... We tried everything

=> This is not present in the BEA's report.
=> This is what the two F/O said to their captain when he came back...


On the other hand, nothing appears in the transcription in the book from 02:10:15.9 to 02:10:27.
I.e. it's missing the "Alternalte law Protections (lost?)" from the PNF at 02:10:22, which is present in the report from the BEA.

I think Otelli had access to a different version of the transcription (a previous draft, perhaps?) while the BEA has total access, of course, but choose not to publish it in extenso (for the moment, at last).

Overall, the book shows two things:
- A crew may be more "relaxed" he ought to have been to fly in the ITCZ (prior problems)
- A crew that does "not understand" the situation, and whose actions are beyond logic or procedure ... This is best shown in the book that the report of the BEA.

That's after a quick (and uncomplete) reading.

[Lyman]

NARVAL. If the THS is trimmed to .1 g less than elevators command 1g at cruise in a/p, will it chase .9g if the a/c neglects to cancel that order after the loss of auto pilot? Is that perhaps why it stopped at less than full UP at the STALL? It hadn't zeroed at the start of its uninterrupted migration to 13.9 degrees NU? Without that cue at the start of UP toward the STALL, was it flying anything other than g? Not following the manual input?

AZR. fwiw, "je ne comprends riens..." was part of a leak, early on. It was not claimed by BEA, but BEA did in general rue the release of unapproved data in a memo. No source could be identified for it, but it was discussed here. So technically it is not "new", only re-released, and still not disavowed by BEA......

If it is accurate, it is a bold condemnation of the aircraft and its pilots.

Yes, and the aircraft. For those who disagree, I can only point out the public side of the behaviour and docs exhibited by the BEA. Review them, and take note how the interface among the principals has been a design/build from the outset, and it is yet to reach QA. It is not a report so much as it will be a creation.

One guess as to the goals of the "ARTISTES"

[OK465]

From the appropriate document: (this may have been presented previously)

Max roll rate in Normal Law: 15 degrees/second

Max roll rate in Roll Direct: approximately 20-25 degrees/second (varies with speed and config, but this figure IS MAX)

If you feel this is 'twitchy', be careful (and smooth).

I could get a roll rate of about 60 degrees/second out of a 727 with partial spoiler deployment (increased spoiler roll differential)

That's minimally 'twitchy'.

Max roll rate for a T-38: 720 degrees/second

That's 'TWITCHY'.

[CONF iture]

… but why does it jump to +5000ft/min shortly after the disconnect, and then drop abruptly back to approx. zero?

http://i45.servimg.com/u/f45/11/75/17/84/af447_21.png (http://www.servimg.com/image_preview.php?i=117&u=11751784)


- The part after the AP disconnect has some logic :
Whenever FD reengage, they do it basic mode, which is HGD – V/S.
The selected V/S commanded by the FD will be the current V/S at the time of the FD reengagement.
There is almost good correlation between both FD and V/S SEL V/S traces, but not entirely.

- The part before the AP disconnect raises questions :

Why the SEL V/S is cycling from zero to -5000FT/MIN ? That’s not commanded by the crew.
When did start that regular cycling ?
The V/S trace in red is partially masked by the green line, but seems to indicate an oscillation getting stronger, up to the AP disconnect.

http://i45.servimg.com/u/f45/11/75/17/84/af447_23.png (http://www.servimg.com/image_preview.php?i=119&u=11751784)


It could indicate that the AP was trying to follow that cycling SEL V/S ?
What does indicate the AP/FD VERTICAL MODE trace for that very period ?
What does indicate the AP/FD VERTICAL MODE trace for the all event ?
Where is the AP/FD VERTICAL MODE trace ?

[DozyWannabe]

- The part after the AP disconnect has some logic :
Whenever FD reengage, they do it basic mode, which is HGD – V/S.

If procedures had been followed, the F/Ds should have been switched off until the problem was solved.


- The part before the AP disconnect raises questions :

The V/S trace in red is partially masked by the green line, but seems to indicate an oscillation getting stronger, up to the AP disconnect.
It could indicate that the AP was trying to follow that cycling SEL V/S ?



Because the red trace is masked it's hard to tell, but it could equally be the lumps and bumps you'd associate with turbulence. Some confirmation that SEL V/S is not used in the mode the aircraft was in would be useful - but there are plenty of explanations, such as the FDR using that channel for something else at that point - I'm almost sure the negative peaks indicate a bad value rather than anything selected though.

Let's reserve judgment until the final report before we get our knickers in a twist though.

[Lyman]

CONFiture

Please note in your second graph above, (the truncated version), That the a/c is shown oscillating in vertical speed up 1000fpm, down 1000fpm.
In autoflight. This is actual vertical speed, not selected.

The Selected trace covers it up, but I think it may be important.

edit: Sorry, this is repetitive, and Dozy squeaked my out. I'll leave it, so there is a record of my notation. Not like me to jump the gun before reading your complete post (as if).

[HazelNuts39]

Because the red trace is masked it's hard to tell, but it could equally be the lumps and bumps you'd associate with turbulence.The graph on page 42 of Interim no.3 shows V/S in better resolution, and indicates that the variations are due to turbulence. See also elevator activity at the bottom of the same graph.

[Mr Optimistic]

The regular periodicity and constant amplitude of the 'zipper' trace shows it is not a real world effect. Some sort of quantisation effect surely. Although the graph shows segmented vertical traces that may be limitations of the printer producing the graph. Is it every other recorded/printed sample ? Notice that in CONF iture's post the red trace in the bottom graph sows three similar similar blip and again it happens to align upwards/downwards to one of the major y axis grid lines. Suspect the plotting software myself.

[Dani]

If procedures had been followed, the F/Ds should have been switched off until the problem was solved.


It is a strong guess that they never switched of Flight Directors, otherwise you would hear a remark of the two operating pilots on the tape.

[jcjeant]

It is a strong guess that they never switched of Flight Directors, otherwise you would hear a remark of the two operating pilots on the tape. From pilots who don't call any procedures ... ? :=
Le pilote de gauche : «Remonte ..remonte…. remonte…. Remonte !!!».
Le pilote de droite : «Mais je suis à fond à cabrer depuis tout à l'heure».
Le commandant de bord : «Non non… non… ne remonte pas.. non.. non..».
Le pilote de droite : «Alors descends».
Le pilote de gauche : «Putain… on va taper. C'est pas vrai !»
Le pilote de droite : «Mais qu'est-ce qui se passe ?

You are optimistic :ok:

[jcjeant]

AlphaZuluRomeo
Note that the BEA is right when it wrote:
"This transcription mentions personal conversations between the crew members that have no bearing on the event, which shows a lack of respect for the memory of the late crew members."I'm not sure the BEA is right on this one
Or you release all or you release nothing
Releasing fragments is bad than better ( the evidence is here before our eyes .. with all imaginable scenarios and speculations that the few lines of the CVR have induced in the endless posts) .. if transparency and credibility is the BEA (new?) politic
The families of passengers need also respect and have right to know even if this will hurt the crew families (when their relatives have failed on duty)
Releasing fragments of information is a lack of respect for the victims families
Victims families need the same respect as the families of the pilots
Release of entire CVR is not only when heroes are in the pointing end (Sully and al) .. it's also for those who fail ....
Life is not a bed of roses
The truth is sometimes hard to hear

[rudderrudderrat]

Hi Dani,
It is a strong guess that they never switched of Flight Directors, otherwise you would hear a remark of the two operating pilots on the tape.It's more than a strong guess - it's reported on page 74:
"The Flight Directors were not disengaged by the crew, but the crossbars disappeared."

If I was flying at 02:00 and with all the other noises and attention getters going off whilst keeping the wings level in ALT Law, I also may have forgotten to ask for the FDs to be turned off - simply because they had already disappeared from view.

They seem to have simply remembered their previous training (further down on P74)
"The two copilots had only been trained for the emergency manoeuvre at lower levels, in the course of which the pitch attitude to adopt is 10° or 15°."

[AlphaZuluRomeo]

jcjeant,

I disagree. I'm OK with the BEA policy, here.
If a full transcription was officially released, the "doubters" would then ask for the audio. If the audio was released, the "serious doubters" would then ask if the audio hasn't been modified...
That's a confidence issue. If you don't trust the BEA (or the NTSB, which does just the same (*)), then you won't thrust anything it releases...

(*) expect UA93, but that's another story, with FBI implicated

"The families of passengers need also respect and have right to know" => I agree with that.
"Releasing fragments of information is a lack of respect for the victims families" => define "fragments of information", please.
To my eyes, informations which explain the accident is enough (and whole, once the final report is done). And it's not fragmental, regarding the inquiry/accident. Calling it so is not really "fair"...

[AlphaZuluRomeo]

They seem to have simply remembered their previous training (further down on P74)
"The two copilots had only been trained for the emergency manoeuvre at lower levels, in the course of which the pitch attitude to adopt is 10° or 15°."
I'm not convinced...
- not clear call of the procedure
- the said procedure asks for pitch 10/15° and power TOGA when low level, the crew initially just adapted pitch (and thrust to CLB)

I've read another hypothesis about "why did they pull". Don't have it saved here (@ work), will post it later (from home) but basically the hypothesis was they did try and follow the bird, which was erroneous due to UAS.

[GerardC]

How could they have "followed the bird" from the start ?

BEA page 75 : At 2 h 10 min 47...... The Flight Directors not having been disengaged, the cross bars disappeared and reappeared several times without it being possible, at this stageof the investigation, to know what orders they may have indicated nor to establish if these orders influenced the actions of the PF.

FWIS, there was no attempt to use the bird before captain's suggestion :
BEA page 76 around 2 h 11 min 42.....the Captain said several times “take that”, doubtless speaking of the FPV.
Hence the messages :
02:11:00 - .1/WRN/WN0906010210 228300106FLAG ON CAPT PFD FD
02:11:15 - .1/WRN/WN0906010210 228301106FLAG ON F/O PFD FD

02:12:10 - .1/WRN/WN0906010211 341200106FLAG ON CAPT PFD FPV
02:12:16 - .1/WRN/WN0906010211 341201106FLAG ON F/O PFD FPV

[AlphaZuluRomeo]

GerardC,
The thing is, the hypothesis was the first I read & think "hey, I see the logic".
I didn't had time to check all that (besides not being knowledgeable enough to have all answers), and remember having been confused when checking the BEA text (your quote & other §) vs the FDR traces... Will check what I can & post later.