Hi,

Instead felt .. can they have seen ???
That's not seat TV screens installed in the Air France A330 ?
This in flight video system (info channel about the flight) was functioning or not ?

I think a 40 degree bank would have made me put my drink down and tighten the belt.

Gums,
I suggest you have a look at this interesting and well documented internet site you kindly gave us in one of your previous posts: "The Blackbird Archive". SR-71 Online - SR-71 Flight Manual: Section 1, Page 1-135

we don't know yet, but I am sure this vital parameter is recorded in the FDR data and will be in the next report - if not, I suggest it's a major regulatory failure that you should take up with the relevant authorities! Furthermore, I suggest urgent investigation is needed into whether or not said info channel samples and displays air data often enough and accurately enough to indicate a 10k fpm ROD, whether or not it correctly relays stall warnings, and whether or not said warnings are inhibited below 60kts IAS. :rolleyes:

RetiredF4 - small note. Could you change the subject, "tail was falling faster than the nose"? It conjures visions of a plane split in two, which didn't happen until impact. Without breaking the plane in two the tail can only fall faster than the rest for a short time. When it hits 90 degrees, or sooner, it must then fall at the same rate as the rest.

My take so far
 

My take so far.

Hoping to not offend every person on the site. If I do not then I have failed.

I’m just starting to formulate my pretty close to final assessment on the crash. Not much different than all previous feelings.

The Pprune blogs and discussions raise some interesting points and while careful to not ruffle any sensitive feathers, the bulk of what I’ve read so far is pretty much way out of line and off base but nevertheless informative in getting a handle on what the outside world feels about it.

The problems I see are that when you get too deep into the minutiae you miss the forest for the trees.

Among the problems (in no particular order) are the events themselves;

1) In icing which in turn causes pitot tube failures – all 3 of them. So, a triply redundant system fails all at once.
2) This airplane, so reliant on the info from the probes simply shuts down – robbing the pilots from desparately needed information upon which to take action.
3) The auto-pilot and auto throttle click off.
4) The pilots are left with no cogent understanding of which system is controlling the aircraft and unable to figure out the level of control they do have.

The bloggers have a different opinion on the same systems and no one seems to know for sure what controls what on the airplane, and who is doing what to whom.
Further, they have the luxury of sitting in a warm comfortable chair looking at a computer for days and weeks on end trying to analyze what the pilots should have done at the very time they are dis-organized, scared, bouncing around in the middle of the night in a horrendous storm, who must act within literally seconds to analyze and figure what went wrong, what works and what doesn’t, and hopefully do something right.
The test pilots themselves stated that they never contemplated a plane going into a deep stall, and therefore were never able to train pilots to deal with it. Even in the safety of a simulator which never leaves the ground. The emphasis always was to train pilots to veer away from the “approach to a stall”. Simple enough.


5) What has never been addressed is to me the key element: the 7000 ft per minute climb to close to 38,000, when the plane itself could barely maintain it’s maximum level of 35,000 (even though they mentioned wanting to climb to a higher altitude but could not because the temps at their altitude were too warm.)

Note: A normal climb in instrument conditions is a moderate 1000 feet per minute climb. Which I do not know if the plane could attain at that altitude and weight.
A 7000fpm climb could only occur if the pilot nosed up and traded speed for height. First of all an insane maneuvar If it was intentional. Because the result would be running out of speed and altitude at the top which in fact it did.

Alternatively to me it is likelier that an updraft pushed the airplane up. Note in the meteorologists analysis he speculated that there were updrafts that could be as high as 60-70kts which translate to 6000-7000 feet per minute. Whether or not in fact that was the case.

I do know (know?) that powerful thunderstorms are capable of very strong force winds that can easily toss a plane around a lot. Many crashes attest to that.
I’ve personally been involved in strong winds that I could barely overcome. But fortunately in anticipation always carry excessive speed and so far successfully evaded them. But this is close to the ground where the air is thicker and therefore more responsive.

6) One more question I’ve never seen addressed is, when things go awry, or components fail, with time permitting we have checklists that spell out what to do and in what case. Of course some things occur that require instant action, but here with so many things going wrong, it is essential to do the right thing at the right time.

A more comprehensive read out of the Voice Recorder will give us clues to what they were thinking and trying to do.

(note- Not sure if you are familiar with a Quantas A-380 that landed in Australia with multiple failures. They had 5 qualified check captains in the cockpit and it still took 45 minutes to resolve all of the failures and run all the checklists. It ain’t simple.)

(I must respond to the Ministry of Transportation’s analogy of the flat tire: It is more likened to not a flat tire, but the car rolling over and over and the driver covered in blood and then trying to navigate a road with the bridge out. What does he do and when?)

7) Finally to me one thing is certain. If they didn’t fly head on into a thunderstorm, none of this would have happened. Cost more money? Perhaps. Take more time? Perhaps.
Fly a different route? Why not? Land at an alternate? Cost money, Takes time, but ask the passenger, what does he think?

And finally again for a bigger question: What to do about all of this? Scrap the airplane? Scrap the technology? Impossible. And way too costly.

However, there are some homilies that apply. Be careful. Any port in a storm. Better safe than sorry. Penny wise and pound foolish.

bearfoil, I missed this the first time I read it. When I was reading RetiredF4 reply to you this quote REALLY bugged me: "This is a heavy a/c with beaucoups energy to sustain a short climb of 3k feet?"

What does mass have to do with the price of altitude in terms of speed change?

Kinetic energy is 1/2 mV^2. Potential energy is mgh. So the mass washes out of the equation. So a 3000' climb would give "gh" = 1/2 v^2 = 96000 ft^2/s^2 equals about a 438 '/s velocity change or about 300 MPH.

Of course a clean heavy aircraft will have this simple equation modified less by air friction than might a nerf ball. But somehow I figure military fighter jets are not nerf balls either. I'd expect the military jet tradeoff to be pretty close to the AirBus tradeoff in terms of altitude gain and velocity lost.

But, then, what do I know? I'm just an engineer.

RR_NDB, please meet BEA Release, especially the rather highlighted piece of the report.

A "sharp fall" is not a gradual drop.

Mr. Optimistic, please review the Tim Vasquez plots of the storm and the plane's position in the storm. Check the visibility of the Moon at that time and location.

In order to see you need clear air, a light source, and something to see. I submit that they had two of them at some point but never had all three. I'm not sure such starlight as might have managed to get through the upper layer obstructions would have been enough.

edit: Specifically the half Moon was in its last 40 minutes before it went down. They were well into the storm. Maybe enough Moonlight was able to get through to show some glints on the ocean surface. The Moon was on a line with the line of clouds, though.

Henra,
Drivel? You got to be kidding me! The only drivel is this that produced by this quasi accident investigation from the BEA.

It is perfectly acceptable to suggest that the aircraft configuration was sub-standard. The BEA report is so vague and ambiguous that it is obviously only possible to make sense of it by some process interpretation, and it is obvious what interpretation was intended. In the course of releaseing such an incomplete picture, it seems that it is perfectly acceptable for the media to insinuate that the pilots were substandard despite the aircraft switching off its warnings and dynamically changing its behaviour during what would be the upset recovery phase of that flight.

Savrin, this is from the June 2009 report:
This is from the 30 November 2009 report:
Neither believes this is a wiring problem. What makes you insist WRG means wiring rather than warning? I realize there are WRN and WRG messages. There does not seem to be a distinction between them as listed by BEA.

A coincidence that would cause an AIRINC bus to quit working in only one direction would be surprising. And if it's not an AIRINC bus (or multiple AIRINC busses) then it's a multipin connector with inputs and outputs on the same connector. Why would only one direction fail? Why would it fail only in modest turbulence and not be discovered before that turbulence? That's too many hard failures at once for my tastes.

Heathrow Flyer - sure the leaks stopped. AirBus has no incentive to leak anymore.

JD-EE

Chill ma'am, have a cocoa. You insinuate with a broad brush that Airbus has no further need to 'leak'. Does that mean you have begun to look a bit askance at the player(s)? I think 447 is entitled to negotiate energy for altitude, No?

Wait, what is the net deltaE? Can I say that? From 0.82M to tail slide in 60 seconds? At an average velocity of (Reported) 4,000fpm? Both engines were running at cruise thrust, I can't see where my opinion deserves such savagery.

Explain? Small Data, Bold imagery?


edit. I should let RR speak for himself, but you miss the logic in his example.

He speaks of Onset, Emergence, and Presentation. Gradual, it is an ok thing.

Are you thinking the airdata was bunk? That the reads were bogus? They could have been actual, which would explain the attenuation of the cricketSTALL <60knots. And its reacquisition for the "Real" cricket Stall.

The a/c thought it was ok to climb, it helped. It trimmed while the PF worked the elevators. At the top, the elevators were exhausted, and the THS was 'stuck' (to include PE, possibly)?

Hi,

infrequentflyer789
You can be sarcastic (if I well understand your intention) .. it's not a problem .. and I like also black humor :p
Nevertheless .. be sure that the families lawyers will try to know by all means if the passengers suffered before their final fate ( knowing they were to dying)
It's a important point for lawyers .. as the financial compensation will be far more substencial if they can establish that the passengers suffered before dying .....

Wow - you go away for a few days and the thread almost goes belly-up. From what I see there are now attempts to argue that the BEA's press "note" should be treated as a report, and thus the BEA deserve to be slammed for not releasing enough information (which is IMO utterly ludicrous - why do I get the feeling that the NTSB or AAIB would not be under this much scrutiny?), people still trying to blame the aircraft and systems based on the flimsiest of theories, and many of the same people arguing that to do otherwise somehow equates to "blaming the pilot". Full marks to PJ2 and others who've been trying to keep things shiny-side to the sky.

I'd love to know how you've come to that conclusion. I've been reading the therad from the start and I'm pretty sure that other than a couple of interjections, no-one has been arguing that the accident was the result of "pilot error" and leaving it at that. In fact the only people I've seen trying to apportion blame on this thread are the people who are constantly looking for ways to blame the aircraft and the manufacturer based on their own personal agendas. Pretty much everyone else has (wisely IMO) said "wait and see". As I said, very few other air accident investigation units tend to release CVR transcripts until a final report is written - why the undue pressure from some on here towards the BEA?

Isn't that a bit cheeky, seeing as all we have is a press note and a lot of speculation?

Not unique to this aircraft, as has been said countless times. When this happens the correct thing to do is fly pitch and power. Not that this is necessarily easy when you've got a bunch of warnings going off, of which at least some may be spurious, but eminently do-able.

Uh, if a pilot is incapable of working out that upon A/P disconnect that the system that is controlling the aircraft is in fact them, then there's something seriously wrong in their training, surely?

Again, those on here who are either FBW Airbus pilots or who have systems-level knowledge seem to know exactly what's going on. Most of the confusion has been engendered by people throwing theories in either from a position of relative ignorance or because they have an agenda.

Wrong again. The "test pilots" would have been quite capable of taking the aircraft to a genuine stall as part of certification testing. You're confusing line pilot stall/incipient stall training (which certainly looks deficient with 20/20 hindsight) with Airbus's own testing of it's aircraft and systems.

That's an apples/oranges comparison. There's a major difference between troubleshooting an engine failure on a relatively new aircraft type with all-new engine technology and getting things ready to come in for a landing, and diagnosing a pitot probe blockage/loss of airspeed data on an aircraft that's been in service for over a decade.

Bearfoil
Bearfoil, do you ever stop to take a breath? Your logic was flawed and the engineer pointed that out. You should really review your thoughts a bit before posting.
And FYI, AF447 never did a tail slide as you seemed to infer. I suggest you read/re-read Davies "Handling the Big Jets" for comprehension.
If you don't want the engineers and physicists to pounce on you, try to avoid stomping all over Newton's laws and relevant facts that BEA has released. Of course, if all you wish is attention, carry on.:rolleyes:

Bearfoil
 

Oi mate! ..."The a/c thought it was ok to climb, it helped."

The aircraft is nuts and bolts, circuits and wires and magic copper coils.... but it doesn't think.
GIGO, and you know it.

...and where are you getting that the THS was "stuck"?

PF Action in Last 30 secs - Did He Increase Thrust?
 

Quote:
At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications". At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs.

I have deduced from all the learned comments here that nose down inputs were probably made during the last 30 seconds of flight. Do we know whether increased thrust was initiated by the pilot who took over in those last 30 seconds and if not would it have made any difference ? Was the AoA still too high for the aircraft to gain enough air speed for adequate lift ?

System "Pitot DSP are amplifying" Pitot problems?
 

Hi,

BEA sequence is: AP quits, AT quits, RH roll, PF action, SW, SW... Sharp fall from LH Pitot then a few moments later from ISIS Pitot

I suspect the "processing" of Pitot data (signal conditioning, voting, etc.) is amplifying Pitot problems. Probably (to be confirmed by FDR) AP, AT quit before ISIS showed lower speed.

The speed falling seems typical of stagnation point and not drain. And the event seems to be "short lived". Question? The a/c System needs this kind of sensitivity? Why can not during short duration failures remain alive? Well, this was discussed earlier and IIRC they are developing a "band aid" to deal with this "short term" Pitot failures.

In summary, my rationale is:

1) An EW seems to be simple to implement and may be could be useful (as a band aid) to alert to something more serious.
2) May be the a/c System can still operate properly using "improved" algorithms or even also using alternate data (while Pitot´s during short period are not delivering same output).
3) We need to power modulate Pitot´s with extra Watts:8 (last but not least) while waiting R&D, Cert. and perhaps new type of sensors for "real redundancy".

RR-NDB

"The speed falling seems typical of stagnation point and not drain."

I agree. However, if the drain plugged first, the first invalid excursion of a/s would be an increase. If the aperture plugged up with the drain, stagnation, and "frozen" sense of "a/s" read while both holes remain plugged. If the drain unplugged before the Aperture, the ias would approach zero.

So, if these pitots plugged in this fashion, and close to the same time, the A/S would be reported as "accurate", and faster than she was actually flying.

Also, a rapid and consistent increase in a/s could trigger WindshearAlert. It could also trigger OverSpeed alert, etc. These artifacts are present in the ACARS.

bearfoil, it is documented that AirBus was frantic with the coming air show. I presume they were demanding a release to show their aircraft is not at fault. That is about all that the release shows. The aircraft did what it was told. (It obfuscates by not showing any definitive data that might indicate the aircraft supplied the pilots with inadequate information.

The release was made.

Somebody lost incentive to leak.

Was it the victim's families? Was it Air France, whose pilot was shown in a poor light absent a "why" in the data implicating training or aircraft data or aircraft data or presentation? Was it Thales? Was it who?

Follow the money says it was AirBus.

And of course, that is purely circumstantial evidence. Are there other candidates for the leaks?

bearfoil, on the second issue I took issue with the implication in your words that the mass had a great deal to do with the "heavy" being able to trade velocity for altitude. In a vacuum it had sufficient velocity to loose 300 miles per hour to gain 4000', if I remember the numbers in question. A 50% decrease in mass would not change that at all in a vacuum. In air it might change it a few percent due to the imperfect energy transfer. Some would be lost to air friction.

A balloon, if you could get it to mach 0.82 would lose way more than 300 mph to climb even a fraction of 4000' due to the wind friction of its shape. But most aircraft designed to fly up there can probably make that trade pretty efficiently. So declaring the mass had anything to do with it suggested you thought a lighter plane at the same altitude and velocity (on its own power) would not be able to make that full tradeoff.

I guess I was being nitpicky with some wording that set my hairs on edge.

I spent good money for those physics classes.

bearfoil, and third....

The BEA data explicitly calls out a sudden change not any gradual process. How are the two reconciled?

edit: And it cites the sudden change as being downwards from 275 knots, the
cruise speed. So there was apparently, in the data presented, no prior increase in speed.

3holeover, I'll give the bear that one. It is quite natural to anthropomorphize inanimate objects. Why else are vehicles referred to as "she" so much in America?

"The a/c thought it was ok to climb, it helped," merely expressed the concept that the plane was designed to fly and performed accordingly.

(See, bear, I jump when it seems like there are outright conceptual errors or inconsistencies between assertions or conclusions and data. When you are merely being human I'll side with you. Otherwise I'd lose the right to cuss like a sailor at my computers.

@ Bearfoil: Also, a rapid and consistent increase in a/s could trigger WindshearAlert. It could also trigger OverSpeed alert, etc. These artifacts are present in the ACARS

I don't think the Windshear Alert can trigger at all. It only actively (assuming the same piece of kit is used on the 'Bus in AF design spec as in many other airlines) starts looking for windshear when the RadAlt is below 2300ftRA. That is when warnings can be given.

Hi JD-EE,
is correct - but it ignores the total starting energy.

They were Initially flying at M.8 (about 480 kts TAS (Vi)) at FL 350 (h1).
Shortly Afterwards they were at FL 375 (h2) with a new TAS Va

I/2 (M Vi^2) + Mgh1 = 1/2 (M Va^2) + Mg h2.

If you do the maths Va = 368 kts TAS.

The reduction from 480 to 368 kts (112 kts) was converted into an Altitude gain of 2,500ft.
From time 2.10.05 at FL 350 they had an IAS of 275 kts, so would have finished at FL 375 with an IAS of about 211 kts. (275*368/480) .

Just to point out there would be no visible increase in indicated speed if common drain blockage gradual and indicated speed is under auto control. And Mach 0.8 @ FL350 @ ISA +10 is closer to 272 knots according to my calculator, probably within 'about' and lines up with the rudder travel limit.

Agreed that this deduction by the media is baseless and unfounded with the information at hand.
But we should not reduce our level to the one of the mass media.

Please let's discuss it on what is known or reasonable to assume and not some blunt generalisations or completely unfounded wild speculation. Let's leave this to the media....

Hmm, sounds logical at first glance.
On the other hands sales of transport aircraft is not a spontaneous decision made in the morning at 10am during an Airshow visit.

These are long running processes beginning loooong before such an event. Very often only the formal publication of an order will be communicated during the event.
And the decision processes behind are almost exclusively driven by economics, prices, fleet considerations, maintenance, etc.
Emotions do not have much place there.
Therfore I seriously doubt that this preliminary publication will have any impact on aircraft sales one way or the other.

I also can not believe that BEA will dare to paint a picture of the events only to have two months later a real report which contradicts the general lines of this preliminary note. Would be too embarassing.
All in all my assumption is that the general lines of this note will match quite well to what has happened from a factual perspective but it surely lacks the more subtle things which contributed to the why. And it is often the subtle things which make people act the way they do.
The devil's in the detail.

I wouldn't be surprised if the outcome of this investigation reveals to some degree that automation, introduced to reduce pilot error, may be the source of making pilot error.

Henra,
Thanks for your latitude. The point I am making (badly) is that it simply is not possible to determine any cause from the report that was relased by BEA. There are too many missing facts, ambiguous sequences and vauge quantifications. Additional evidence that it is not possible, is the hundreds of pages of posts that are no nearer to agreeing an interpretation of the report, never mind the actual causal factors.

If my point is even partially correct, just what was the point of this report update?

An idle thought, prompted by some of the ideas submitted on this (and other) threads:

In gliding we are taught the concept of the 'Yates effect' (named for aerodynamicist AH Yates), which goes something like this:


One wonders if what goes for gliders is also applicable in an airliner flying at FL350 / M 0.83. I know from personal experience (stubble fire plume entry, for example) that the Yates effect can be huge: a glider may require a rapid change of pitch of >+60 degrees (!!) to avoid exceeding max manoeuvre speed, shortly followed by an equally aggressive (zero 'gee') recovery to a 'normal' pitch attitude to avoid the stall.

An unusually severe 'seat-of-the-pants' lift force experienced at the same time as an (assumed) unusual attitude and loss of airspeed references - followed by (speculation) an incorrect recovery to normal pitch attitude - *might* have initiated this upset.

DozyWannabe, 1896

Ok, but "quite capable" only implies that the a/c was tested beyond
incipient stall conditions as part of the certification process. I've
read elsewhere that this is not the case, as it is considered too
dangerous. This of course begs the question: If the a/c hasn't been
tested in deep stall, with known good recovery procedure, how can
one expect the pilots to recover under such conditions ?. http://images.ibsrv.net/ibsrv/res/sr...lies/cwm13.gif

I think I mentioned this in another post, but got no response. Perhaps
you have a reference to a document that describes the full certification
process, including deep stall recovery ?...

Sciolistes, 1912

Interesting question and on balance, i'm with the cynics on this one,
with regard to the air show. The damaging effect that wild
speculation can have not only on sales, but also passengers who might
refuse to fly Airbus if they think that they are in any way unsafe, demands
some sort of response. Tell a lie or smear often enough and it becomes the
truth in the minds of many.

I do think the update was intentionally vague and with incomplete information.
Such a release would be considered quite unprofessional in some quarters, but
it wouldn't be the first time that objective science has come into conflict with
politics and big business. At least, they don't burn you at the stake these days.
I don't doubt for a moment that BEA are anything but diligent in their efforts and
that they will report the truth. We don't need yet another conspiracy theory to
understand the timeline here.

In a nutshell, that's life, get over it...

Some thoughts:
 

To those that want to divert this thread with idle speculation regarding what the passengers may or may not have been aware of - knock it off. This has no place within this thread (remember: this is the Tech Log...?) and can serve no useful purpose. Lawyers will no doubt play that game to the max when the time comes, but within these pages I can see nothing but theatrical imaginings - leave it alone, please.

:ok: to rudderrudderrat for the airspeed calc a few posts back - you seem to have hit the numbers on the head.

JD-EE: Do you not think that (a) the BEA will in the fullness of time produce a full report, that would leave them looking like a bunch of incompetent idiots unless the majority of the recent note is essentially the meat and potatoes of the incident? I mean it's going to be hard to take them seriously if they suddenly switch story-lines. What we have been given is the frame upon which, no doubt, the fine print will become overlaid. I find it hard to imagine anything being added that is so astounding that collectively make a virtual 180 with our thinking here. (b) You seem to believe that Airbus is the only player that has a significant hand in this game? Do you not think that Air France might also be rather interested in what the BEA are saying? At the end of all this a large and ugly lawsuit is lurking and some large $$$ are about to discussed, so I really can't see the BEA being pressured to apportion blame (implied or otherwise) without the data to back that up.

Several mentions have been made a 'deep stall' - why? This is a specific stall condition mostly defined as "A condition such that the turbulent wake of a stalled main wing "blankets" the horizontal stabilizer, rendering the elevators ineffective and preventing the aircraft from recovering from the stall." Neither the BEA note, or any of the more 'thoughtful' contributors believe this aircraft was in any kind of "deep stall" I think it fair to say.

For 'gums' and his musing on the Viper deep stall, I would characterize that as something different, largely due to the non-stable aerodynamics of the aircraft, that the FBW system normally kept under control - you bad boys just found a way to get into a flight condition that I figure the designers didn't think you'd find!

Finally, there has been some speculation that the pitot issue bay have been drain blockage leading to an increase in airspeed indication... where is this imaginary event coming from? Does anyone here rationally think that the BEA would not mention this? If this gradual speed increase was occurring, the AT system (prior to disconnect) would normally be attempting to compensate I would surmise? I am pretty sure that the information released would have mentioned this, since it would have been precipitous to the whole accident sequence. Finally, the zoom-climb energy calc would not work, unless the aircraft speed was not as declared (275kt).

Thanks for the link PJ2.
In this case, only the left PFD speed was recorded, probably something to do with the fact that VH-EBA was not the Enhanced version of the 330 ...
It appears that the Digital ACMS Recorder DAR didn't deliver the two other speeds neither.

The similitude in the ACARS messages with AF447 is relevant, but one particular message is missing, the one Svarin is talking about :
WRG:ADIRU1 BUS ADR1-2 TO FCPC2

Calculation of Mach
 

DJ77 (#1833), thanks for your view. Whilst the Wiki references and the descriptions of mechanical instruments (and some ADCs) add credence to the view that TAT is not required to calculate Mach, I recall that temperature is in the root of the equations.
Mach is the ratio of speed at a point to the local speed of sound; the latter definition requires temperature. As has been shown, suitable manipulation of equations can reduce the measurement requirements to pressure / pressure difference for mechanical solutions, but IIRC this involves small errors or a look up table.
However, in a digital system, where programmers might be reluctant to use resource sapping square root calculations, alternative derivations of Mach may be used.
Thus, with open mind, the question is; how is Mach calculated in the A330 ADC?


CONF iture (#1825), info noted. However, with continuing open mind, it has not been established that 7000 ft / min is a real velocity or just that which was recorded (displayed). It appears that the aircraft did climb, but to what altitude and how fast might be poorly defined. Note that VH-EBA ‘descended’ suddenly 300ft, but this was only the recorded indication.
Considering a highly dynamic situation in AF447, with many parameters ‘failing’ or outputting erroneous values it might be difficult to draw any conclusion as to what the airaft actually did, perhaps excepting AOA, e.g. if the speed altitude anomalies were partially restored, how might the VS calculation account for these sudden changes (VS is an inertial / airdate mix?)

bearfoil, 1901
Not sure I agree or understand all this. My take on the pitot
probe fault modes and their results would be:

1) Drain hole blocked: Would only cause an small increase in
airspeed at cruise. The drain hole must be small to avoid loss of
resolution and non linearity at low air speeds, as the probe has an
approximate square law response. Whatever size hole is used, there
will be some non linearity, but this would normally be corrected for
in the sensor electronics via lookup table, in much the same way that
pressure error correction is applied for airframe probe position errors.

2) Both stagnation and drain hole blocked: This would fix the airspeed
at the last measured value before blockage. The value determined to a
degree by the sequence in time in which the stagnation and drain ends
became blocked. If the drain hole subsequently became unblocked first,
the air speed would decay towards zero. If the stagnation end became
unblocked first, the airspeed would indicate the true value + drain hole
pressure loss. Output either no change or step function.

If both ends are blocked by ice, the drain hole end will be shielded
from the cold airflow and could be expected to unfreeze first. Thus,
the airspeed would tend to decay towards zero initially until the stagnation
end became unfrozen, when the airspeed would ramp up to true value.

Take this to bits if you like :) ...

Chris,
Fantastic, thanks for the top tip :ok:

I hope this hasnt already been discussed
 

In the aftermath of the accident the plethora of automated signals sent from the doomed aircraft were widely publicised. Has this information been compared to the details of the accident released so far and in particular the time line provided by the BEA?

In my laypersons opinion, surely a comparison would yield some additional insight into what the pilots experienced and what caused the tragedy.

As an aviation enthusiast and very part time passenger, it boggles my mind that a modern automated aircraft could get stalled at 35 000 ft + and not carry on flying at some point before crashing. :ugh::eek: