Rob21, I understand (from the old thread) that this is not at all uncommon for bodies floating in water. The flexure and water action effectively strips corpses.

oldengmkr, that report is rather interesting to this non-pilot for a couple reasons.

I had something modest to do with developing GPS. So I am well aware of the likelihood that planes will end up perfectly aligned vertically if they are on the same track. This raises an interesting question for such cases. Should there be a generic track offset of maybe 400 meters per thousand feet with some mean flight level being on the nominal track so those above deviate port and those below starboard? It should be possible to maintain that separation very closely.

And I also received with interest your primary reason for posting this. I believe some remarks have opined something of this sort is likely to be what happened to AF447. Take the 340s upset and add to it loss of airspeed indication; and, I (still) consider it very unkind for the AP to metaphorically speaking throw up its hands and say, "Pilot has control." That's an inaccurate and impolite way to phrase it; but, it surely gets attention around here when I phrase it that way.

Takata - thanks for the notation on the debris map!

What is the large (largest?) item/section far to the right of the engines (circled in blue)?

http://i337.photobucket.com/albums/n...vidcap025B.jpg

oldengmkr;

Thanks for the link to the AAIB Airprox report. I note that the analysis focus is TCAS and RVSM issues, whereas I am mostly interested in the autoflight aspects as they relate to AF447. Would you know where to find Appendix B?

mm43,

Yes, it´s clear now. I reached this conclusion by myself after reading about "marine snow".:ok:

From what I heard in the BEA videos, this is the penciled square zone where they were looking in priority for the CVR/FDR and they called it "the heavy debris field / North East zone"; There is also, inside it, a black circle with a black cross drawn on it: I guess it is where they discovered the FDR's chassis.

For sure, no but they are labeled by hand on this map: "Engine #1" and "Engine #2", so I guess also it means what you think.

I can't read most of the details written about the wings and I'm not even sure the western one is finally a wing as it looks like one from its shape on those video frames but when I cross-checked with other documents, I believe now that I may have been wrong. The first big piece of wreckage west of those engines seems also to be captioned "wing".

The legend at the top of the eastern wing looked like a couple of capital letters followed by "MLG" but it may be simply "WING". "Wing" is also handwritten below it (most captions are a mix of French and English). I can clearly read "fuselage section [unreadable]" from various captions.

No, no, no, no!
There is definitively not enough pixels on those frames to go further into the details and, well... it is also killing my eyes.

You are right about the engines circled in blue and I have no idea what is this lonely large piece of wreckage east of them (which is not pictured on the other map). I'll guess this is a fuselage part which had some buoyancy remaining and that drifted back to this place as all the wreckage, excepted it, seems to be obviously spreading from East to West in the deep.

autoflight etc.
 

JD-EE

It is, at the very least, "unkind" of the AP to "dump" control of the aircraft back in the hands of the pilot under such highly adverse circumstances - perhaps beyond the skill of any human to deal with. I find the work being done by the folks at Bielefeld University (AG RVS - Welcome to Networks and Distributed Systems) on the human/machine interface encouraging in this regard. Hopefully they, or others engaged in such work, will soon find a better mode of the AP relinquishing control when circumstances are beyond its capabilities. They have some additional comments on the AAIB report here: AG RVS - Computer-Related Incidents with Commercial Aircraft. The AAIB recommended that overtaking aircraft indeed adopt a lateral separation approach but its implementation is complicated by rules in differing flight juristictions. Bielefeld also has an ongoing analysis effort related to "Computer-Related Incidents with Commercial Aircraft" found here: AG RVS - Computer-Related Incidents with Commercial Aircraft.

HN39

Unfortunately, I have not been able to find Appendix B of the AAIB report but I will search further later today. I had hoped the Bielefeld link I mentioned above would lead to the Appendix B but it did not. The AAIB, IMHO, "punted" on the autoflight aspects of the incident stating "The fact that this law was not triggered until 10 seconds after the autopilot disconnected was a random event driven by the severity of the turbulence. Had the turbulence been more severe at the first encounter and coincident with the overspeed warning, reversion to AoA law could have been triggered as soon as the overspeed condition disconnected the autopilot. Nevertheless, it should be noted that had the autopilot remained engaged, the AoA law would not have been invoked because it is inactive except in manual control." Note the italics and bold are mine for emphasis of that sentence. Perhaps AF 447 also experienced such a "random event".

MLG = main landing gear.

That is what I thought at first [?? MLG] at the top and below in small letters "wing". But, more likely, it is simply written at the top also "WING" in capital letters as the first sign is a large "W" instead of two unreadable letters.

takata

Bonjour. Thank you for your debris map, it was most welcome.


Let me run past an elementary proposition, to see if, as a simple set, it establishes some foundation.

Three miles port side of the airway, at cruise, the pitots Ice, and airdata is lost. Due Unreliable Airspeed, the ADIRUS 'quit', auto flight/autothrottle are lost, Normal Law is degraded to Alternate, and the pilots need to quickly manage the a/c to retain control.

The exact mechanism of LOC is not known, but the a/c contacts the water below, Belly down, Tail low, mostly intact, and is destroyed. From the debris field, it appears that due to its very compact spread, there was little current to cause dispersion, but the direction of the current is suggested as East to West, and that if the debris field is searched further to the west, at some point debris would reach its ultimate distance from the heavier pieces.

No conclusion relative to the flightpath can be discerned from the orientation of the debris ?

No conclusion can be ascertained from the debris as to which direction the nose of the aircraft was pointed at impact ?

The impact point can be estimated to some degree with data known about the rate and distance of the sinking engines, by unwinding its path down ?

The Captain's rest ended at 0200, and he was likely in the cockpit, perhaps even taking his Left Seat at the time of the Master Caution (Cavalry Charge), leaving only the F/O seated and restrained ?

The attitude excursions allowable by the a/p affect the ride of the a/c; did the a/p disconnect due its inability to manage the a/c ( Turbulence ), or due an already Unreliable A/S ?

Merci beaucoup, mon ami. Vous ete l'Homme.

Rob21,

From the article in the New York Times where the author met with the coroner in Brazil who did the autopsies.

http://www.nytimes.com/2011/05/08/ma...ted=1&_r=1&hpw

I don't think that a body losing clothes would retain a necklace.

Hi Bearfoil,

At least two automatically monitored reliable ADMs were needed to keep all flight enveloppe protections active, which was not the case anymore at this point (02:10). Then, most automatisms turned off, but were supposed in "safe mode" (A/P, A/THR, PFD, RTL,...), kicking ALT2 law, until the crew took some action by selecting which AS data was still to be considered reliable (by rejecting other). Note that this state (ALT2), once kicked on, can not be reversed until after landing. Then, the action required was for this crew to monitor all their informations about curent air speed after having selected a safe and defined pitch & thrust profile. This aircraft control should not have been compromised by this event alone, meaning, an adequate crew reaction (or without reaction at all. In some other cases, they just did nothing until A/S anomalies ended by themselves).

I'll add, four or more minutes later, as the exact time for impact is still to be confirmed.

Well... the impact point was certainly very close to the vertical of those engines. Considering that below surface currents are negligibles for such a mass, they would sank straight down from where those impact forces will send them; mm43 observation is relevant: 35 m separation instead of the original 17 m or so under the wings.

I'm feeling that most of the wreckage at the bottom is somewhat related with the heading at impact (WSW), but it may be due to an illusion without having on hand the specific model showing all the mechanics involved.

Not so sure about that.
The contrary is more likely: taking one third watch for each pilot at cruise level (From departure FL200 to descent), The capitain being on the deck at both end, he will have watched the first cruise leg which might have ended around 0200.

Icy conditions (see my many posts about that) doesn't imply any level of associated serious turbulences. But ice issues are acertained by pitots fault, consequently A/P and A/THR certainly kicked off due to an unreliable airspeed event, freezing also the Rudder Travel Limiter at its cruise settings for Mach 0.82 cruise level flight.

takata;
Exactly. The aircraft was stable before the loss and any change in that state would require input, (crew, aircraft weather); if none, stable flight would remain, requiring only minor adjustments until the event passed, as shown by the previous events. The aircraft wasn't "out of control", and there was no need for the pilots to "control" the aircraft...as with any abnormality, there was the need to respond as per training, in this case, to ensure that everything remained the same, within the bounds of possibly-turbulent flight. A loss of airspeed data does not cause a loss of control.

For a number of reasons, I concur with your comments regarding the crew break. It makes sense to infer that the RP was in the left seat, as P2.

oldengmkr;

I was wondering when or if this AAIB report would surface again and had been considering the events and responses described for some time. The link to the Report was first posted by delta092b on the second thread (of four, this being the fourth "major" thread) on June 5th, 2009, post #239, four days after the accident.

The report as quoted above, states: "Ten seconds after the autopilot disengaged, the corrected or phase-advanced angle of attack (a computed parameter which is not recorded but can be calculated by Airbus Industrie from the DFDR data) reached the 'alpha prot' value. This angle of attack excursion beyond alpha protcaused a change in the pitch flight control law from normal law (NZ law) to angle of attack protection law (AoA law). "

To keep any response to a reasonable length, the CAoC or "Corrected Angle of Attack", (I hadn't seen the term "phase - advanced" in my research), is calculated by the ADIRS; it may or may not be recorded. AoA is certainly recorded; I have accessed it and monitored it in turbulence using the ACMS-Parameter Alpha Call-up mode, available in the MCDUs.

Among other uses, it is used by the SFCC [Slat-Flap Control Computer] as part of an anti-retraction mode which is based upon CAoA, (nominally, 7.5deg) and <148kts CAS) if I recall.

The outcome for the A340 is dramatic: 6000fpm up, a loss of 65kts or so and a climb of over 4000ft.

We must bear two things in mind, (notwithstanding the crew's surprise and concern in re the A330 800ft or so above them!) - a) For this to obtain for AF 447, the aircraft would have to be in Nz Law before the other events occurred, and b) as per the Report, full forward stick would return the aircraft to Nz Law (from Angle of Attack Law).

What I don't see explained in the report is why the AoA Law was triggered. Was it Mach-related or low-speed related? Was it turbulence-related, and if so, what was the AoA and what were the exact circumstances (re Mach number) that exacerbated the event and possibly opened the door for subsequent factors to trigger the AoA Law? I don't think this was just a case of "Mach buffet".

We do have the evidence which shows a very high vertical impact force. A number of theories are "in play" so to speak as to the loss of control, including some which contemplate a controlled descent followed by loss of control lower down. Possibly - nothing we know verifies this or a LOC near cruise vice lower down - We can only infer but not conclude.

One item I have considered is the UAS QRH checklist, which can, I think, be misinterpreted. Examining flight crew training manuals explains the correct way to handle the memory drills and subsequent read-do checklist but I think this notion should be examined if only to dismiss it.

gums;

Just waiting and reading. There is really nothing to say at this point.

There will be time enough for robust debates after the data is read and some general hints at what happened are provided. The discussions will be interesting when a 3rd Interim Report is released in due course, (which I would expect to include the maps, an outline of the way of LOC, some flight data examination and comparisons with the ACARS series).

HN39;

I was unable to locate "Appendix B". If the report has something to contribute to an understanding of the AFS especially the reconfiguration of flight laws from Nz to AlphaProt Law, I'm sure what there is in this report will be available and its relevance hopefully established. There are some primary differences in that event: For an AlphaProt Law response, the aircraft must be in Nz Law as the response (HIGH AoA and PITCH ATT) wouldn't be available in either Pitch Alternate law.

As we are aware, the AD that was released on December 22, 2010 states, "However, in some cases, the autopilot orders may be inappropriate, such as possible abrupt pitch command.

In order to prevent such event which may, under specific circumstances, constitute an unsafe condition, this AD requires an amendment of the Flight Manual to ensure that flight crews apply the appropriate operational procedure." The AD does not mention those "specific circumstances", nor do we know to what event(s) the characterization of "abrupt" refers, if any.

Perhaps the dots are still too far apart to see viable connections but this event and the one to which I refer above concerning the UAS QRH Drill, are possible areas to focus upon along with weather.

takata

In preparation for the next report, I am trying to tie up some loose ends for my own edification.

"I'm feeling that most of the wreckage at the bottom is somewhat related with the heading at impact (WSW), but it may be due to an illusion without having on hand the specific model showing all the mechanics involved."

This is a puzzlement. There is a point in the 'sea' where 447 hit, may we call it the IP (Impact point)??. I will make it the center of a circle, (or the apex of a cone), and derive some information from this cone's base, a circle drawn (on the bottom) around the vertical spine of the cone.

I'll make it concentric circles, at certain radii from the base center, described by the location of various debris, Engines, LG, other, etc. Now the direction of the stream of debris is certainly a result of the direction of the sub surface flow, mated to the velocity downward of the various masses as they sink. It cannot have any relationship with the direction of the a/c's nose, or any other part of the airframe as the impact happened.

All motion was arrested of the aircraft at impact, and the system became an independent ballistic aggregation, subject to density of mass, surface area, and other considerations having nothing whatever to do with "En Ligne de Vol". So my opinion is that the Direction (Heading, under protest), of the a/c at impact is absolutely random, and could have been exactly opposite of WSW, or any other bearing. The various pieces in the debris field were at the mercy of the sea, and it's whims. How could any direction present in the Field of Debris be anything but simply an increasing radius from the "center" of the circle described above ?? Not only is it not known now, it will never be known, the "direction at impact" of this a/c.

Are their possibilities of "Last recorded bearing" on the DFDR ?? And a time stamp at impact ??

To me, this accident almost certainly had a pedestrian cause, but circumstances were lain in front of the flight that could not be avoided. The absolute procuring cause may not be known, ever, but I think enough is already known to suggest some improvements in the industry.

I will sit on my hands until some new developments pop up.

Thanks, Olivier. From you and others I have learned much...

bear

edit. From comment on this thread, my understanding is that Captain launched, and established cruise, then took his rest. Three hours later puts his schedule at "Re-enter, and assume command". (0200). I am not persuaded that UAS is a given, that Discrepant a/s data from the pitots caused the disagree. A sudden, and unrecoverable LOC would point to the doubt that UAS occurred. As described by PJ2, UAS is not a guarantee of LOC, controlled flight continued ?? The boxes will out, but the simplest, though unlikely explanation may be that discrepant air velocities at the pitots were station related (position on the airframe), and not caused by ICE. This makes the a/p drop the problem, not the result. The positioning of the control surfaces can be done by either Automatics or Manually, and both have limits, neither one is infallible, ask gums.

PJ2;

Thanks for your reply. (Remainder deleted after further consideration).

Conf_iture,
Thanks for reminding me tactfully about the Dassuault Mercure having a cockpit AoA gauge: it rings a bell – sorry, no pun intended. (Did it also have a high Vmo?) Am now waiting to be corrected re the Russians, and maybe the Anglo-French "pointy one".

takata,
Without invoking further eye strain, are you confident of the annotations for engines #1 & #2? I'm wondering how easy they are for the recovery team to distinguish in the debris field. For example, I'd be surprised if the accessory gearboxes are handed, and the pylons and cowlings are presumably elsewhere.
You will remember the argument some of us had, when the debris field was first pictured, about debris-orientation versus heading/track at sea-level impact? [wink] (Don't get yourself into hot water like I did.) You suggest:
"I'm feeling most of the wreckage at the bottom is somewhat related with the heading at impact (WSW), but it may be due to an illusion without having on hand the specific model showing all the mechanics involved."
That was my feeling at the time, but – if labelled correctly – the engines seem to have switched sides.

PJ2,
Am wondering if the engagement of Alpha-Prot Law could be reconciled with the Alternate Law message.

Chris, I should be in Paris next week, so maybe I can ask about the Mercure.
The Anglo-French "pointy one" (aka as Concorde), did have an AoA indicator (bottom left...), but I'm not sure to what extent it was included in the scan, or when.

pj2 / HN

My reading is partially as yours.

Crudely: This "protection" is entered at the same point as the AP disconnects. 0.86M is the limit, 1st excursion <<In the two second period after the initial speed excursion above Mach 0.86 the Mach number decayed to 0.855>> to 0.87M disconnected the AP. The small / brief excursion probably did not generate much of a pitch up, but <<and then increased again to 0.882. It remained above 0.86 for two seconds before decreasing and remaining below 0.86 for the remainder of the turbulence encounter>> the next probably did more (longer / greater exceedence) and the combined 2 excusions now left the aircraft in a climbing attitude.

Meanwhile <<Five seconds after the autopilot disengaged, the thrust levers were closed>> and <<Ten seconds after the autopilot disengaged, the corrected or phase-advanced angle of attack (a computed parameter which is not recorded but can be calculated by Airbus Industrie from the DFDR data) reached the 'alpha prot' value>> i.e. we had a climbing attitude, zero thrust, and reducing (due windshear) M No hence IAS etc., all at Cruise Alt. Hardly surprising it got to Alpha Prot - it would have to eventually.

I don't wish to judge, but 'AP Disconnect' is a Red Warning, and whatever else is going on, my training is someone (preferably HP) has to say "I have control" and fly the ac (Rule 1 of any emergency...)

NB the duration of this climb is 35s... that is a long time to leave an aircraft with nobody flying - especially in severe turbulence. 18s is still a long time, and the A340 hardly deviated in altitude more than the A330 (AP in throughout).

I only add this in answer to the points above - I have not followed the AF330 theories as to exactly how this incident might relate to that accident.

Chris
Vmo = 499 kts (925 km/h) according to several Mercure 100 datasheets. A "civilian fighter plane", as pilots used to say... :E

bearfoil, the New York Times article states, and I am doing a bit of paraphrasing, that the BEA is adamant that AF 447 was never south of the LKP.

Putting some things together
 

Gentlemen,

my thanks to oldengmkr for posting some links of high interest.

To the attention of those interested in my preferred subject which is flight controls and their potential for lethal mischief, if I may, I would like to gently suggest reading these highly theoretical, mind-numbing documents :

AG RVS - Computer-Related Incidents with Commercial Aircraft

Byzantine fault tolerance - Wikipedia, the free encyclopedia

http://www.ann.ece.ufl.edu/courses/e...l%20System.pdf

In very short : Byzantine faults are those special failures where faulty data gets propagated. Relevant ?

The general effect of these faults is erratic or unpredictable system behaviour. I am talking flight controls sytem here. Relevant ?

The theoretical response to these particularly obnoxious faults lies in the direction of 'distributed' and 'reconfigurable' architecture for a computer system. The last link points to a paper that was published in October 2009, and produced by a team of scientists and a select few engineers from the thread subject matter manufacturer. Relevant ?

At least, I for one find this concept of Byzantine fault very much relevant to our present mystery. Applied to flight controls, it certainly gives me the creeps.

Svarin

Edit : first link was posted by oldengmkr, thanks again, very enlightening.

SaturnV

I don't disagree, have I intimated somehow she was South/LKP?? At any time??

What I do say is if takata is right, re: the "Direction of Flight", and the indexing of the engines, then AF447 was 'heading' ENE when she hit. This in no way conflicts with the "direction" of the debris, his thesis is workable either orientation of the a/c at impact. The engines will be first down, and if the current didn't alter its direction, (much) then the lighter debris merely overtook (horizontally) the heavy stuff and landed "beyond" it, later. The fact is, since the ENE direction puts the lighter stuff further East than the heavy things, it gives some leeway (timewise) for the light things to travel further than the engines in the horizontal.

I am thinking the pilots deviated left/right of the airway, and at some point beyond it (the LKP), made the decision to return to land back in Brazil, (or other, dependent on severity of the circumstances). Having completed the turn, they were on a heading back when LOC happened, and she went down quickly. We don't know her heading at LKP, merely that she flew through it.

Even if on the airway, they may have turned back, and the "new" heading was WSW, but displaced the width of the diameter of the turning circle (something like 4nm). This pretty cleanly falls in line with the Impact Point.

If BEA is holding fast to "no position" South, fine by me, how is that fatal to the discussion?? Except to say, they may have evidence not released. Oh, and the fact that AF447 was S of the LKP the entire flight, until her passage through LKP.

A/C direction* when hit sea surface
 

In my post #598 i put:

Is the picture showing the debris field an indication of the plane´s TRAJECTORY? ("heading")

Observe i put TRAJECTORY (and "heading" is under quotes)

Posting a similar question again:

The picture:

http://takata1940.free.fr/debris_field1.jpg

Is coherent with a/c hitting surface in the attitude BEA said?

(With a trajectory estimated as approx. 75 degrees, based on BEA pic)

If not, WHY?


(*) DIRECTION necessarily the same of HEADING during unusual attitude

I have read every post on AF447 from day one, so apologies if I have missed the answer to the following question - to those with 330 experience.

You are happily up high in the cruise, on AP, Aft CofG etc..

Time shifts somehow and you are now at 5,000 ft, still in cruise trim on AP, and have to get onto a stable 3 degree approach to land. Would you have time to re-configure the aircraft completely for an SOP landing?

If not, could you get it set up for a GA?

etc...
All the ex Air Inter craft were AoA indicator equipped.
See this this pic of an A320
which has both an AoAI and an HUD.

HN39, quote:
I'm wondering about the possibility that Alpha-Prot engaged due to turbulence at, say, 2:09:50. Too much of a coincidence perhaps?

Can Alpha-protection be activated while the AP is engaged?

Re the NAT-TRK A340, think you and NOD are right to consider the possibility that the initial pitch-up was caused by overspeed protection, which also disconnected the AP. With speed back in limits, Normal Law would be restored. As NOD implies, absence of sidestick movement by the PF would allow a 1G (approx) trajectory, with speed decaying (and AoA rising) until Alpha-Prot was activated.

The report highlights the plethora of aural warnings (overspeed continuous-repetitive-chime plus TCAS resolution call), which it says would have initially caused the AP-disconnect "cavalry charge" to be inhibited. There is no separate W/L for AP disconnect. It uses the same Master W/L as the overspeed warning.

EDIT
I should add that there are other indications of AP status:
(1) the right-most FMA (flight-mode "annunciator") on each PFD;
(2) the green LED on the respective AP push-button (or absence of) on the FCU (glareshield).


PS
Thanks, Lemurian, re AoA indicators on all Air Inter A/C, and the link to what is otherwise my old office...
Thanks, ChristiaanJ: just checking you were still paying attention. ;)

Putting some things together
 

Svarin,

Your valuable post makes me remember "Black Swan" of Nicolas Nassim Taleb (NNT), Professor of Risk Engineering at NYU 's Poly Institute.

May be a more complex way to talk about Murphy´s law

PS

And using a phrase Bearfoil put in Post #597:

"Nature is relentless in her punishment of those whom are ill-prepared."

PS2

There is a link of a NNT paper on Fukushima tragedy.

I think that the original comment by Jean-Paul Troadec, was intended to mean that the crash position was not south of the LKP. By that I believe he, or anyone else for that matter, had no idea where the aircraft was going after the final AOC report at 0210z.

The point I am making is, that as posited by takata, the aircraft may well have been airborne for some time after 02:14:30z, - and could well have ventured south of the LKP. On the other-hand, as pointed out by the MAK/IAC, - dives, spirals and spins can result in rapid loss of altitude and the impact position is often close to the point of upset. I don't think we have determined whether the UAS (if it was) resulted in an immediate LOC, and therefore it is difficult to understand that an effective distance of less than 5NM was covered between 0210z and the Impact Point, at whatever time that occurred.

In the debris map, which way is North ?

Edit:oK, thanks

Chris;
I must apologize for airing a couple of thoughts which I quickly withdrew after re-reading the AAIB Bulletin, the Fcom and the AF447 ACARS messages.

The NAT incident shows that Alpha-prot can be activated with AP engaged, but causes AP disconnect. Therefore this scenario doesn't fit the AF447 ACARS messages, which indicate that AP disconnect was immediately followed by reversion to ALT law.

In the NAT incident M=0.882 was reached at 14:21:43, but the pitch up began at 14:21:50 when Alpha-prot law was engaged. Once Alpha-prot is engaged, it remains active until a nose-down command is given with the sidestick (see the FCOM and the AAIB Bulletin). Until that occurs, "the AoA protection law seeks to hold the angle of attack constant at alpha prot".

The vertical railway lines are spaced 5 meters apart. They run north/south and north is at the top.

Thanks Svarin for the interesting post.
In your first link, the article previous to that was very enlightening and sounds similar to what the AF447 crew may have faced.
AG RVS - Computer-Related Incidents with Commercial Aircraft
It relates to an eerily similar scenario on a B777 off Perth in 2005. (faulty airspeed indications, autopilot 'doing the wrong thing' etc)
Here is a snippet fron the page....Makes you think about FBW and 'Byzantine fault' propagation and / or tolerance...

Help!
 

Bonsoir Lemurian,
I'm very glad to see you here tonight, Sir!

Could you, please, explain specifically to our friend Bearfoil, what Air France procedure should have been during this particular flight concerning the pilots flying legs.

I remember your explanation showing that the commandant de bord should have taken the first leg and could have been relieved shortly before the first incident happened.

What would be the theoretical timming on the flying deck replacements?
Or, am I wrong?

Heading
 

Scpeculating on the a/c heading when she hit the ocean ... any bank left or right would yield a sharp turn, right or left.

Hi Chris,My poor eyes are still able to distinguish #1 (up) & #2 (bottom) the way I pictured them. The possibility is that those numbers may have been used for wreckage identification rather than port/starboard correspondance if they were unable to indentify their correct place under the wings at this early point.

Pylons, capots (or part of them) are definitively elsewhere -in Toulouse- as they were recovered floating -it was pictured in the BEA annexe to the second report showing those aircraft parts already recovered.

Or, they were not numbered for this purpose (possibly from the early high scan passes as this document dated from the REMUS search before the first ROV dive)...

A very rough model of the wreckage spreading at the bottom related to surface ending place will take into account three categories of wreckage:
1. pieces buoyant;
2. pieces buoyant for some time, then sinking;
3. pieces going down immediately.

* Category 3 should be a very close carbon copy of the surface impact spreading (before sinking) considering what little time it will take before reaching the deep where the currents are barely nil.
* Category 2 should drift on surface as long as it takes to lose all its buoyancy, then sink also mostly straight down. Some pieces may consequently end at some distance from their initial place at impact.
* Category 1 should be recovered far away if spoted at the surface several days later.

Overall, this is not very surprising that the engines are lying at the edge of the debris field (excepted one large piece) considering it is presumed that they were the first to hit the surface.

That was true at the time, but things have been slightly (and discretely) modified since, maybe partly due to that event.
The text in the FCOM is a bit ambiguous but says that it is now also possible to leave the AoA protection if the sidestick is at neutral or pushed forward, for at least 0.5 seconds, when alpha is below alpha prot.

Nothing is that simple with the airbus, a very complex machine indeed.

We'll be told (or not ... ) if some bizarre coincidences mixing unreliable airspeed indication + protections played a trick on AF447 ...

Possible model to explain debris field shape
 

Looking to the debris field of pictures below,

The model could be of a/c hit surface at approx. 75 deg. direction:

1) Eng #1 hit surface, detaches and dive decelerating from a/c trajectory speed, reducing it´s horizontal speed gradually.
2) LH wing separates, breaks and it´s "water speed braking" capabilities (due it´s still present profile despite broken) decelerates faster than fuselage.
3) Fuselage breaks and its pieces "showers" to ocean floor. It´s parts decelerating as a function of it´s characteristics (mass and geometry) creating the debris shape.
4) Eng #2 detaches, "fly" some meters or so and dive reducing it´s horizontal speed gradually (traveling a litle bit further than #1)
5) RH wing separates, "fly" further than eng #2, hit surface, breaks and dive accordingly it´s "water speed braking" capability (RH LG mass and shape of still attached parts and panels)

http://takata1940.free.fr/debris_field1.jpg

http://www.seattlepi.com/mediaManage...628&height=471

IMO is more logical the a/c trajectory of 75 deg than 255.

Sorry to have introduced an error in that legend but the western "wing" position is false (and I have no clue about which one is the RH or LH).

In fact, it seems that one wing is largely broken in smaller parts, east of the squared area, all over the square, and also west of it. I'm trying to roughly compile that from several other frames from those three videos.

I'm not sure also if the Main Landing Gear (like I captioned it) is really with the southern wing part. On the other hand, the Nose Landing Gear (NLG) is also broken in several parts roughly in the middle of the squared area and north of it.

Supposing a/c hit water with some horizontal speed (*)
 

Hi, Takata

Still supposing they hit surface first:

1) When they separate from a/c IMO they would travel further than other a/c pieces. Reasons:
a) A/c horizontal speed
b) it´s inertia (mass)
c) Less "water braking capability" (better hydrodynamics)

Hence it seems to me that they are in the "end" of the debris field farther from the point a/c hit surface.

* And no 'important" local submarine currents, what is probable due the debris concentration.

PS

My objective now is to have some insight on the trajectory of a/c at the end of it´s "flight" from FL350. I am anxious to learn at least how far the debris field is from LKP. I understood they did not revealed yet the recovery ship position. Who knows it´s PSN?

Pylons, capots (or part of them) are definitively elsewhere -in Toulouse- as they were recovered floating -it was pictured in the BEA annexe to the second report showing those aircraft parts already recovered.


I can't seem to find the report. Could somebody please link me!

Thanks