Neptunus Rex

Can we please get back to the main plot here?

ChristiaanJ

Well, let me quote just one.....
That's what I call a personal attack.
And please, don't run to the mods this time, to weep on their shoulder again.
Hiding behind yet another 'user ID' is despicable....

Lyman

ChristiaanJ. Of all people, I know tyou can help. The elevator record? How is it that the traces of elevators/THS don't show much response to the PF's mortar/pestle? frrom airtren #1870?

3holelover

Bear, Lyman, or whoever you are... If you'd ever handled hydraulically actuated controls on an aircraft, you might have noted the same thing... the more demand there is, the more likely will the surfaces be responding a little slowly to your demands... call it a kind of hysteresis. As more fluid flow is asked for (many of those actuators use a fair bit of fluid from stop to stop!), the more the pressure can drop and the slower they'll go.

Owain Glyndwr

Bear, Lyman,RWA or whoever.

We know you have difficulty with simple concepts, and I am probably wasting my time, but one more try.

With a FBW airplane operating under C* laws there is no simple relationship between sidestick movement and elevator deflection. The sidestick movement is a delta 'g' command and the FCS adjusts the elevator movement to suit the actual flight conditions. Moreover, the FCS has a pitch damper function, so the elevator movement is further modified by a term that depends on pitch rate. You simply cannot make the sort of comparison you are attempting - it is futile.

Secondly, as has already been stated many times, the THS movement is not linked directly to elevator movement either. The THS is moved in response to the SUMMATED stick demands over a period of some seconds. This quantity varies much more slowly than the actual elevator deflections, so the THS movement is correspondingly sluggish.

No great mysteries, no cover ups and no failures!

takata

Trajectory = pitch/power settings + turbulences.
THS is long term, slow rate... do you know what is trim?
Did you even look at thrust change?
Control surface efficiency is never "absolute", being all the time affected by aircraft equlibrum in the air.
As this has been already discussed previously, maybe you should try some reading instead of constantly trolling and hijacking this thread with your (not so funny) clones.

xcitation

It's amazing how graceful/forgiving the A330 behaves below its flight envelope (stalled, storm and low airspeed)?

Before this incident if you asked me if a transport can be controlled at ~30kts in a storm then I would guess no, probably tumble and break up. Remarkably the reality is yes albeit requiring aggressive stick inputs to maintain level wings!

Was there a special reasons why AF447 remained controllable at ~30kts? Did the free fall/stall (100+kts vertical) acting on the superstructure provide aerodynamic stability even thought the wings were not flying?
Why did asymetric engine thrust/drag not induce a spin?
Why did the ailerons/rudder generate enough force to keep the a/c in a graceful attitude albeit oscilating in roll?

Lyman

Power. CONFiture has framed Power for me. So OK. Dozy has said she is not twitchy, so OK. Trim is familiar, so OK. I understand Hydraulics.

I also see that THS has not killed her, it comes in only after the STALL. It is at -3 from ap loss to STALL. The aggressive action of the Pilot is not relevant, except in the long term, takata, you have said that.

So, from handoff, this aircraft exhibits no bad habits, except perhaps following the orders of PF?

I guess the question I have left is, she is well protected, docile and easy.

Until it is absolutely necessary that she be protected, then she is not?

All those protections, but when they are truly needed, they hide?

If controls are deliberate, then mayonnaise is not important, but the controls will slowly take her to STALL? Three pilots are wanting to know what is going on, but she is....silent. Sweet.

At STALL warning and STALL, the THS trims to the stop NU? Fix that?
With a committee of three on deck and focused, can we see what the other guy has done, is doing? Fix That? Can we off some of the extraneous ECAMS when we are about to die? Fix That?

It is a machine. get up off your knees and stop genuflecting.

Jutta

peut-être je suis la seule genuine ici
bisous (quand meme *rire*)

you should have understood by the way I posed my naive questions, that that was quite feminine and until now I've never met a real man being able to copy a woman in whatever role imaginable et bien sure vice-versa (sorry for the OT)

takata

[Edit: Very sorry Jutta, and welcome (ouch!); I was obviously completely wrong about you!]It is not funny Bearfoil, you're completely lost into your stupid stereotypes, please, stop playing with people by wasting their time.[Edit: see what happen now, Bearfoil? I'm sure you liked it: even genuine ladies would be treated like silly Bears!]

PJ2

Please ladies and gentlemen, it takes two to tangle. One cannot control another's behaviours, only one's own. If a poster's contributions consistently bother one, go to "User CP > Edit Ignore List > Add User To Your List", then click "Okay", then to exit, place a tick in the "Check" box and click "Save Changes".

The user's name still shows up in the thread but not the post's text. There is a "View post" prompt in the top-right corner of the post so if you wish to view an individual contribution you can do so by clicking on the prompt.

If someone is making your experience here unpleasant, rather than engaging, use the ignore feature and keep contributions to this thread on-topic. If you wish to engage, perhaps the PM feature is a good alternative.

Some enjoy the fight but the thread has deteriorated so badly and there are so many posts to wade through already that it is getting tiresome and unattractive as a technical discussion on AF447.

takata

Of course, you are right and I fully agree...
Until the guy, being ignored by most posters, come back under many identities, spamming, enlighting, his previous postings that always will re-trigger the same odd discussions, over and over again!!

Now, this game is 2 years old.
At one point, all people reading this thread should be aware that someone is constantly playing with them; that many here are wasting their precious time at building serious argumentation; that they are, nonetheless, constantly fooled by someone which is playing this sickening game.

At one point, this should really end, or this thread (and R&N one) won't be worth continuing anyway.

PJ2

As I say, it takes two to tangle. One quickly recognizes someone who is serious about discussing this accident and who has other motives. The second kind of dialogue shouldn't last two years, it should last two or three posts which is all it should take to realize someone is fooling with us. Otherwise, by responding one chooses to become part of the game, sustaining it, which is fine as sometimes it is challenging and fun for some, but it is so at the expense of the continuity and pleasantness of the thread. The truth of things always comes out sooner or later regardless of how one or another wish otherwise and who try to push conclusions upon others by all means available.

The choice too, for some, is not to come here anymore and for many who enjoy dialoguing with serious, like-minded professionals, that would be a shame.

Disagreement, even vehemently so, is different and should be tolerated and encouraged. And it is very easy to tell the difference.

Anyway, I've said my piece. The thread will go where it will go regardless, so we'll see.

ChristiaanJ

PJ2,
Thanks

takata

Wisdom is talking. So lets try it again... and see what happen.

sensor_validation

Back to old obsession:- what exactly was happening just before the incident started - were the controls acting on bad data? I think its possible but only for a few seconds before the air data correctly flagged as inconsistent.

One possible failure mode of pitot tubes when encountering ice is that the drain holes block first and cause a small over-read, then under-read as the total port blocks. With the air speed under auto-control this might not be seen on the Mach No - but may be seen to be calculated as change in wind speed.

Is it it just a coincidence that it all seems to be coincident with the selected Mach drop from M0.82 to M0.80? This seems to have been commanded at 2:09:50, unfortunately the plot of "Navigation Parameters" on English P109 is corrupt while the selected Mach is 0.82 - as mentioned before it appears they are plotting 0 when no update.

The engine N1s start to ramp down from 2:10:00, but seem to have little effect on the indicated speed - but presumably is responsible for the co-ordinated drop in pitch angle? The longitudinal acceleration suggests the plane is slowing (although I don't understand the negative bias on the plot).

It appears the ISIS calibrated airspeed when recovered after the dip is "stuck false high" in period 2:10:10 to 2:10:13 - during which the engine N1s are locked low - but groundspeed doesn't drop off much (perhaps due to plot scale).

It's not all consistent to my eyes, and I hope the BEA can recover more detail data the control hardware around this time (especially the right hand display indications) - BUT - I think you need significant shifts in wind speed/temperature to make it all add up - what if they "nearly missed" a Cumulonimbus?

Mimpe

Im in general agreement with Smiling Ed and machinbirds posts, however the trim issue was a small hurdle to further overcome at the end of a long list of errors. I certainly respect the lifelong experience represented by so many of the forum posts- the kind of experience that safes lives when things go really wrong.

I think in this kind of accident there is a very large list of factors, and they all seemed to concoct for the worst on the day, at the edge of the flight envelope, and the PF's ability.

A few quick matters....I can see a very good argument for visibly linked controls. Its such an aid to situational awareness, and I feel non linked controls are a bit of a by product of low accident rate complacency.

Also,I dont see why an intelligent explicit emergency use of extrapolated speed data with sensible caveats may have at least alleviated the anxiety that seems to have paralysed the situational and perceptual awareness of the crew

The mental fog appears to have descended on the aircrew very early. There must be some professional habbits and training that can overcome what appears to have happened here. How effectivley do AF and the major carriers/ training organisations train to deal with false perceptual expectations/distraction/poor self awareness/anxiety/lax flight discipline/life
threatening CRM issues.

Im not sure how "worlds best practice" pilots do this. I know how I was taught by my most respected instructors and try to practice at my own aviation level.
I try to constantly practice "what ifs" as a trainig tool, as well as reviewing my first emergency responses so they are fluid, at times when they are not needed.
It was that kind of lifelong learning, self discipline,professionalism and deeply embedded training I saw in Sullenberger, that I dealy wish to emulate, and which set such a great example to all.
My day job is medical, but in my years working in emergency medicine, we used to have a saying..." In a crisis, take your own pulse first".

Lyman

There is in accidents what is called the "procuring cause". It is the beginning; what follows is related, and interesting, but subtract this one first "hole", and 'groundhog day', it is as if nothing has happened. Shall we leave it at that?

Of course not. To leave what follows this first slice as irrelevant is foolish, and a disservice to those who paid.

One does not treat the booboo without focusing on the hemorrhage first?

This hemorrhage, this first slice, was one of 32 previous slices. Shall we wander into confusion? Strikes me that Pride and Prejudice, if allowed at all, should wait, until other more pressing matters are dealt with. One could almost get away with saying: This was NO 'accident'.

Generally, to qualify as an accident, it must meet this: 'UNFORESEEN'.

jcjeant

Hi,

That's not difficult to understand
This was the AF (by the directeur général adjoint des opérations aériènnes Mr Schramm) reaction after the disclosure of the BEA report N°3
This man tell already the contrary of the report .. and some plain lies ...
Unfortunately in french but some here will well understand
It's pretty embarrassing

takata

Nothing looks corrupted here. Change of Mach mode "Selected", set at Mach 0.80, occured at 0209:58 (not 0209:50), only 7 seconds before UAS. Previously, it was Mach 0.82 and the blue line drop is readable behind the "Mach Number" green line. Before this change, the flight guidance mode was different ("Managed"), hence it is painted (in blue) differently with down lines, but the top of blue block is showing Mach 0.82 until this point.

I think that it is not a coincidence as the turbulence level slightly increased, hence aircraft speed was reduced... while the phenomenon occured at this point. The conditions were changing: feeling of warming, smelling, noise, etc. The very same elements were also described during other flights encountering UAS conditions.

Maintained airspeed is primary due to momentum rather than immediate thrust change at 0209:58. In fact, it seems that the first result of this thrust reduction was a slight drop in pitch, down to zero or slightly below, which was followed by a small acceleration, small loss of altitude, slightly negative vertical/speed and also an increase of ground speed (turbulence can play its role also). This looks consistent with airspeed slightly increasing up to 0210:07, when ADR1 became invalid. Hence longitudinal g should have followed the same trend. Once this inertia moment was consummed, pitch increasing, low thrust and climb started altogether to bleed airspeed. But this was not effective before five or six seconds following A/P disconnection (about 0210:11, when gentle descent stopped and climb was resumed).

I don't think that ISIS is either "stuck" nor reading "false high" at this point. Last valid ADR1 was 274 kt at 0210:07 and climb was still not to be resumed until 4 seconds later, hence, 270 kt on ISIS between 0210:10 and 0210:13 doesn't seems false reading but actual airspeed.