takata

Hi Franz,
Yes, it will be limited to the duration of threshold excess, when load factor will be lower than 0.5gs, IF, at any time, they applied that much ND, which doesn't seem to be the case either.

Yes they are lost. This protection, like any other active protection, was lost from the start of the event when EFCS is directly set in Alt 2.
UAS is very nasty, only g-load protection (which is passive) will remain and protect the airframe from g-load exceedances.

No, same as above, it doesn't work with UAS in Alt 2. There was no more "Stall_Speed" to refer to for the system to make it working.
"Bank angle compensation", should mean that the system will try to bring back the wings level or prevent any increase of bank angle while reducing NU attitude.

It's not easy to grasp it at the first reading.
When going to Alternate law mode, the five active Normal law protections are lost. But, depending on the kind of fault causing Alternate law switch, two protections may be replaced by Alternate ones (Low Speed and High Speed).
In our AF447 case, with a triple ADR fault, those protections are lost as well, and it seems very bad as they could have prevented this crash.

takata

Hi CONFiture,
You are right, but ISIS includes more functions than default standby. About ISIS access, flying the aircraft from the RHS would make it harder for the PF to check ISIS, which is closer, in the central console, from Captain's seat.

AoA wasn't an issue when speed issues started. I was talking about the first PF reaction inducing the initial climb that could be related to his focus on roll and initial sharp altitude drop. I agree that it doesn't explain why he continued NU orders when, 40-50 seconds later, the aircraft stalled. But disorientation and instrument disbelief could cause the later orders.

It is quite hard to understand.
But, we never faced the same stress and situation as, with hindsight, we are fully aware of many things they may have never acknowledged during this event. Captain's return could have bring some confusion with him. Did they agreed about the situation? Was the PNF nose-down in ECAMs reading while the PF pursued stubornly his false impression of what really happened?

I still believe that a BEA hastily release of raw data would have caused more harm than good. Many things really need to be checked and cross-checked before reporting them to the public. Without expert analysis, it may be very harmful to everybody. Any inquiry needs time, patience and in depth processing in order to avoid mistakes and wrong conclusions.

I would like to know everything, straight away, but not before everything is well sorted out and seriously verified. I'm pretty sure that there will be no final report this summer, as some believe, only an interim one.
We'll see.

LandIT

From takata

FWIW after following this and other thread for many months and wanting to believe the PF reacted to indications (not terrified rabbit pulling up), takata's theory is what I believe happened. That in my view is saying a lot after all the posts and credits takata with a conclusion that has taken so many months of analysing, questioning and thinking.

My worry now is the PF (RHS) instrument datas were not recorded and the BEA may have difficulty concluding about why the PF inputs were as recorded. But I fundamentally believe the PF was reacting to what he saw on instruments (outside was "black", no horizon). I do however think he failed to integrate his feelings from the seat, i.e. G forces over time (which probably began before AP disconnect with subtle descent). I can excuse him from that in the urgency of the situation, but am still trying to understand ~30 sec of 7000fpm climb.

My hope is that the A330 will become even safer (it probably already is due to modified UAS procedures promulgated). Surely we must find a more resiliant way to measure airspeed than those pitot's. But if takata is right, we must find a better way to reliably measure altitude at all times as well.

john_tullamarine

can you explain the different places of the pitots between A+B, can this have an influence of the reliability (ice)

I have little (approximately nil) knowledge of AB pitot statics and only those Boeings which I have flown. Generically, I suspect that you will find both marques are similar with multiple pitots around cockpit FS and statics a little further aft (to stay in a shallow boundary layer region without too much local flow acceleration).

Ice problems are probably a bit too specialised for my general comments to be of much use.

bearfoil

Thales have (had) issues. All a/c operations have 'issues'. Transport does not function in a vacuum. A/C are certifiably up to the challenge, but they do not fly in a laboratory, with scrupilously maintained parameters.

To be safe, maintenance must be relentless. Pitot probes gobble up whatever atmosphere they are in, they have no choice. Salt air, grit, moisture, pollution, it is the fact of life. Thales had drain corrosion problems (from memory, original thread, and subject to flame). So in a bad way, the probes developed a less than reliably redundant read? Maybe.

From takata and his point re: three way adr rejection due discrepant reads, a slight hesitancy may be allowed re: ICE.

IMO, ICE would present as other than an instantaneous three way discrepancy. It seems more reasonable to entertain airflow changes. imo.

I have read only LandIT's repost of takata's post. It is a feast, and his best yet, imho. Injecting TCAS ACARS for altitude suggests perhaps looking at W/S for airflow disturbances?

I am relieved and fully support any writing that gives an objective basis for speculation. Of course the crew were qualified; where in the world did the initial objectivity of this forum go?

LandIT. I spot an idea in your post. "He did not incorporate his feelings from his seat".

Should He? That way lies danger. He was in the panel, making the best sense of what he saw, I would guarantee it. It was in flying by the book that did them in....... Interpreting "G", especially over time, isn't that potentially a conflict with the a/c?

I think takata is spot on. PF was likely F/O, from the RHS. Not relief pilot?

syseng68k

Chris

DozyWannabe, #466

I don't quite see the connection there. It's almost as though you are
implying that you shouldn't fly in any new a/c until it's at least 5
years old, to get all the bugs shaken out, which seems like a spurious
argument.

While you may need to wait a few years before upgrading to any new
version of windows, (I'm still using W2k on one development machine, but
for other reasons), a/c are not quite the same thing. Of course,
statistics can show anything you like, but the answer to that is to take
samples from > 1 data source, especially where a given data source is
suspected to be biased or unreliable.

I doubt if there is meaningfull difference in the figures anyway, as accident
rates, in terms of flight hours are down in the noise...

Lonewolf_50

for John T:

If ice is the trigger for a fault in the function of static ports, what sort of evidence does that leave behind? Your posts leave me an uneasy feeling that a possible fault that left no evidence was involved for a part of the upset event.

If that is the case, it has remained hidden. Sufficient function was retained or regained to leave coherent altitude data for most of the event.

bearfoil

hi Lonewolf.

Give me a steer, here. My take on the accident involves mostly the idea that the initial event happened rather quickly, and was unrecoverable almost as fast.

Aren't 'Upset' and "Loss of Control" two separate regimes? My understanding is that Upset need define one set of criteria, and LOC another.

Upset I think, includes control excursions that are quite recoverable, similar and quite consistent with loss of a/p. Not boring, but not life threatening either. A Loss of Control exists when command of the a/c is lost?

So, for whatever reason, what caused 3ADR reject and ALTERNATE LAW2 satisfies 'Upset'? The zoom climb, at least for now, defines LOC?

Early in #4 thread, I think, the criteria for Jet upset (regardless of airframe type) were posted here. Not so for LOC, but LOC is pretty simply "Loss of Command" (mechanical or Pilot induced?)

BOAC

Whatever barometric anomalies you introduce into the theories, you still have to explain why two competent pilots allowed or caused the pitch attitude to change so dramatically without an apparent word said between them? Here's hoping BEA tell us something useful at the end of the month. Otherwise I'm afraid it just does not 'compute'.

bearfoil

Never having been there before, neither aircraft nor Pilot 'knew' what they were "doing".

At least Orville and Wilbur expected the unexpected.

speedbirdconcorde

Lets all keep in mind when discussing pilot action....we have had 2 YEARS to review, analyse, review, discuss...analyse...... they had minutes....NOT a situation any one of us would ever want to be in...

Eagerly awaiting the next installment from BEA...

Lonewolf_50

"Quickly" is a relative term. Depending upon how responsive your aircraft is, quick time horizon will very.

At some point in a three thousand foot climb, which took about half of a minute, remedy to the pitch problem seems to have not worked, whatever was tried.

For me, thirty seconds is a long time if what I am dealing with is simple attitude flying, but as I have stated time and again, I am at a loss concerning what the PF was seeing (and for that matter, what he wasn't seeing) from the event's onset to its conclusion.
I would use "upset" to describe those unusual attitudes and conditions that precede stall, or other out of control flight, and classify only stall and beyond states as "loss of control."
Caveat: if you have a control channel that doesn't work, you may be, by default, in a loss of control state. If you have spoilers or slats going wild (there was a bold face for that in the A-4 NATOPS that I can vaguely recall) you may be in OCF until you get the asymmetry fixed.
You can call a trim runaway a loss of control, unless you are able to overcome it and regain control. Had that happen in a helicopter once, it was an adrenalin rush, but it was recoverable.

Bear, I am not sure I'd phrase the distinction as you did.

Over the past two years, a number of pilots who have flown big transports into stalls (usually on purpose with that one degree per second entry method) have told us how the stall recovery went. What seems to be true, (other than the deep stall problem of the T tail aircraft) is that recovery is often viable when partial control over some or all flight surfaces is exercised in a particular way, likewise power adjustments, to affect a change in airflow and restore lift, and thence control.

(Aside: If you want an interesting loss of control story, take a read on the Vortex Ring State flight test done by two test pilots for the V-22 Osprey as they investigated one of the V-22 mishaps that involved VRS).

I don't see it that way. I don't think zoom climb is LOC, it looks to me more of an upset. Once stalled, you could argue LOC. I'll let those who are more current in state of the art terms correct me on that, as necessary.
A stall due to windshear is neither mechincally induced, nor pilot induced, so maybe a third category is needed. Or a fourth.

PJ2

takata;
Having done for some time now the work of interpreting flight data in flight data analysis programs I fully concur with your views.

The release of "raw" data is simply never done.

I made the observation long before anything was released after the recorders were found, that the data would not, (and may not) be able to provide us with the full picture of what happened and why.

There is no "magic" in the flight data or the CVR. It is without question, an interpretive process requiring thorough training and long experience. How someone may imagine themselves as capable of doing better alone, is a puzzle.

The release of the traces, (which is a very long way from "raw data"), is sometimes done as part of the report, supporting the text and investigative work. Asking for or even demanding "the raw data" is the clearest indication of how little someone understands the flight data and accident investigation processes.

The impression that "the raw data" will give final, conclusive answers and "we will finally know what happened", is a misconception of the flight data and investigative process. A release of "the traces" without a thorough interpretation would indeed be a serious mistake and could even delay an understanding of what really happened.

While there are a few here whose capabilities have clearly been demonstrated and whose interpretations would benefit from being able to work with "the traces", the investigative process does not work that way and those capable of the work would know and understand that. The vast majority of us are not the "check-and-balance on the BEA" some may imagine themselves to be. When the report and the data are both available, there will be time enough for those who can do the engineering and flight safety work to verify, and critique where warranted.

ChristiaanJ

Thanks, PJ2.
Count me in your camp....

bearfoil

believe it or don't, me too.

When the Reaper enters the room, many present begin to whistle. Human beings function (and desire to) in states that can be managed, and understood. If understanding is not available, we trust others to supply some manner of acceptance by proxy. Lacking any understanding or management, we choose denial.

This is true, and even perhaps more so, for those who believe knowledge is perfection, and there is an answer for everything. There is not, and fear is therefore inescapable, and natural.

It is possible that this Airbus and these Pilots performed perfectly, and the consequence was unavoidable. Life has risks, and to the extent that we honor that, it is incredibly exciting.

I think this thread is back to still water. The BEA report will never satisfy everybody. It satisfies me, and I haven't even seen it yet.

ChristiaanJ

How do you know that?
All we have at the moment is an interim 'cherry-picked' extract from the initial data from the recorders (FDR and CVR) , as described in text format by the BEA, and then translated into another language (English), with all the usual pitfalls of those processes....

Yes, we're all frustrated by the limited amount of 'hard' data we have.

Yet, the BEA report seems to have satisfied the 'meedia', which now have switched to 'DSK', 'Murdoch', the 'Red-haired Witch of Wapping' and other more juicy bits.

If I was working for the BEA (and no, I'm not) I'd heave a sigh of relief. To do serious hard reliable work, it does help not having the media, etc., breathing down your neck. Even if getting a full interim report out by the end of July might have seriously up my holiday.

jcjeant

Hi,

Are you sure ?
Seem's not all meedia

France/Monde | L’AF447 ou le droit de savoir

Lonewolf_50

Thanks for that, I had a momentary visual of The Sun running coverage, page 3 perhaps, of Red Haired Witch's juicy bits, and nearly poked my eyes out with a pencil. (Yes, I still know how to use one! )

The media pressure has got to be a process obstacle for BEA.

Been in a few (thankfully) scenarios in my life where the Media took and interest ... it's not much fun.

DozyWannabe

Not at all - it's just statistically more likely that there will be a marginally higher risk of an incident or accident in the first years of a new airframe's life. The chances of being in an accident when boarding a new type are still incredibly unlikely.

But the facts bear this out - the 727 had a series of very nasty accidents in the first few years of service due to a combination of pilots getting to grips with the tail-heavy aspect of the design in combination with the powerful flaps causing a much higher bleeding-off of airspeed on approach than they had hitherto been used to. Both the Comet and the DC-10 revealed serious design flaws in their first few years of service (and the L-1011 revealed a minor one, regarding the weight -on-column required to disengage the automatics). The 737 proved that it wasn't as longitudinally stable as the 727 (unlike the 727 you couldn't rescue a fast approach by throwing the gear out early) and the A320 had some mode-confusion issues in her early days (of which Habsheim was *not* an example).

Those are just some examples, but I think it's a pretty good rule of thumb. It's a testament to the improving quality of aeronautical engineering over the years that the number of these incidents has gone down dramatically (the 757's record was unblemished until the mid-'90s and the 777 has suffered only a single hull-loss, as has the A340 in service).

Believe me - that's not the comparison I'm making! For a start, home and business OS "teething problems" usually *are* down to flaws in the design and implementation rather than the users getting used to how they operate. This isn't relevant to an aviation discussion though.

Funnily enough, it was A33Zab who brought up the safety record, not me...

mm43

I'm sure the "Red Haired Witch of Wapping" is not featuring in the BEA's analysis of the demise of AF447, and likewise the same lady wouldn't have found anything of salacious media interest worth publishing in her former rag(s).

On the other hand, Le Dauphine's latest article - L’AF447 ou le droit de savoir (AF447 - The right to Know) - is clearly pointing the finger at "crew competence" or lack of it, and to the dubious credibility of Air France.
Protect the integrity of Airbus Industries and make Air France and its employees the "sacrificial lamb" is my read on this Irčne Perrin article.

Numerous issues are raised, including simulator training and management, but nowhere in the article does the word "securitie" in the safety sense get a mention.

jcjeant - Thanks for the link.