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AF 447 Search to resume (part2)

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AF 447 Search to resume (part2)

Old 3rd May 2011, 18:46
  #601 (permalink)  
 
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bearfoil, quote:
"No human endeavour can trump Physics, let alone the parochial attitude of those involved. Why again is the DFDR inside the fuselage and not the Vertical Stabiliser ?? Given the "Good Luck" Airbus demonstrates re: the independent ability of the VS to survive horrendous crashes??"

Another triumph of ambiguity. Starting from the second sentence I've quoted, which phrases are pure irony, and which (if any) are straight? Are we still to infer that the fin separated in flight?

As for the first sentence, and the rest of the piece, I'll reserve comment.
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Old 3rd May 2011, 18:52
  #602 (permalink)  
 
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more hindsight

I could add the following to my previous post on what influenced the search strategy.

The retro drift analysis by the Brazilian Navy and USCG, pinpointing the impact so close to LKP and to the actual impact site, didn't get the attention that it deserved. Because there were other analyses, mainly by Meteo France (based on other models) that gave hugely divergent results.

And also the item that was found on 7 June on the surface of the impact spot was not seen other than an anomaly, while (as mm43 said before) it was probably a floatable piece recently escaped from the wreckage on the ocean-floor.

Moreover, because ULBs normally don't fail the search was very much focussed on that: until 10 July (the 30 days certified + 10 days of expected but not certified days of functioning) nobody was expecting not to find any pinger signals.

It was not after all the vast areas covered by sidescan sonar had not rendered any result either, that based they came closer to LKP again. On the one hand this was determined by what was left "un-sidescanned" and on the other hand on the recent the Russian study that showed how close to the initial upset point A/C that experienced LOC in cruise ended up at 0 ft.

But in one thing BEA has always been adamant: "AF447 has never been south of LKP" (except in cruise of course).

Looking fwd to the read-outs of the recorders......
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Old 3rd May 2011, 19:06
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I think what one infers as ambiguity may perhaps be sarcasm. An open mind is a fertile field.
 
Old 3rd May 2011, 19:27
  #604 (permalink)  
bearfoil
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RR

Is the picture showing the debris field an indication of the plane´s heading?


No, of course not. It shows the direction of the debris, as it sank.

An a/c that is rotating, laterally, out of control, cannot have a heading.

The "system" as it falls, can have a direction, though "random".

The direction of the nose as the a/c impacted is random, undirected, and most definitely not commanded. For the umpteenth time, "En Ligne de Vol" is a fantasy.
 
Old 3rd May 2011, 20:05
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Originally Posted by FlightPathOBN View Post
but as we have all noted in the Titanic, that mass took quite the effort to find.
True, but they were working from a set of manually-calculated DR coordinates that were accepted to be a considerable way off, as opposed to a computer-generated log which showed damn near the precise path the target was taking up until it disappeared.
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Old 3rd May 2011, 20:24
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Kudos for your post

Bearfoil,

it brings up a flaw in the Search strategy
A serious one! Why? ASAP the investigation ends, better for the most important entity of aviation industry: THE PAX and CREW of ALL 330


BEA trumpeted, "Intact at Impact"
We hope we will be able to verify

ACARS to entertain "Continued Flight" into weather
"People are being entertained" Let´s hope for readable boxes and even QAR.


all manner of Radar excuses
N/C

This is how it must be read
I read like that

A "Search" must include ALL areas that are possible
If your objective is to work respecting THE PAX and CREW of ALL 330 and similar planes

even those that fly in the face of the "Reputation" of what are arguably collateral players, pilots, union, Thales, AB, etc.
I remember Michel Asseline of Habsheim 320


AirDisaster.Com: Investigations: Air France 296

To be continued in following post(s)

Last edited by RR_NDB; 3rd May 2011 at 20:28. Reason: Corr.
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Old 3rd May 2011, 20:42
  #607 (permalink)  
 
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Shape of debris in ocean floor

Bearfoil,

What i thought:

Plane disintegrates (falling stalled at unusual attitude) when hitting sea surface with SOME horizontal speed.

My question relates to:

The debris shape in ocean floor is representative of the spreading of debris in sea surface when it disintegrated?

Or derives from sea currents when dived?

Observe i used DIRECTION instead HEADING.

In the text i edited also.

I agree with you that En Ligne de Vol" is a fantasy

Part of the "Entertainment" you mention.
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Old 3rd May 2011, 21:03
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bearfoil;
The direction of the nose as the a/c impacted is random, undirected, and most definitely not commanded.
Sir,
The ship has a "bow" and a "stern", and when proceeding in the same direction as its "bow", the vessel is making "headway". The counter applies if proceeding in the direction of its "stern". This being the accepted case, the vessel at all times has a heading in respect of the compass rose which lies in a horizontal plane.

So, irrespective of the vessel turning to port or starboard, or spinning, the only time there is no heading with reference to our compass is when its bow and stern are respectively in line with the zenith.

Now, commanded or not, the "en ligne de vol" provided the vessel with a heading as would be expected of any vessel "en passage".
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Old 3rd May 2011, 21:26
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RR NDB wrote:
My question relates to:
The debris shape in ocean floor is representative of the spreading of debris in sea surface when it disintegrated?
Or derives from sea currents when dived?
Observe i used DIRECTION instead HEADING.
In my sense, it's not possible to see an heading value of the plane when impacting water.

IMO, I hope everybody here is knowing that the sea floor wreckage parts from EST to West repartition is only the result of submarine flow AND density + shape factor of those parts.

regards
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Old 3rd May 2011, 21:26
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RR NDB

One need not be an expert. At impact, most of the a/c was in structural chaos, and there was no horizontal component after some milliseconds. The debris ended up tight and probably in some sort of teardrop shape, from above. After that which would sink, sank, what formed was a conga line of debris, subject to current alone, no wind, trajectory, nor "Heading". The debris field may have been 600 meters across, maybe not, but what is seen on the bottom is the "target" established upon sinking, subject to rate differences. The trajectory below the surface was down, probably to a precision of 99.9 per cent. Travelling two and one half miles vertically and 600 meters horizontally, if the debris field was as tight as 600 meters, that there was no dispersion is indicative of almost no current, for if there was, there would be a dispersion, heavy to light, etc. The debris field found on the seabed suggests not dispersion but coalescence. Here the "intact at impact" is reinforced, since to fall on to such a small target from 2.5 miles away means that most of the debris at least started its journey as a joined mass.

It may be a language thing, but I doubt it. An object in free fall has a Trajectory, not a heading.

Has one found the second, Starboard engine??
 
Old 3rd May 2011, 21:30
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En ligne

mm43,

En ligne de vol?

Vol=Flight

The a/c hit sea surface flying?

Or stalled at unusual attitude (like a falling "winged brick")?

the only time there is no heading with reference to our compass is when its bow and stern are respectively in line with the zenith
This is why i put DIRECTION instead HEADING in post #599
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Old 3rd May 2011, 21:43
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Originally Posted by RR NDB
I agree with you that "En Ligne de Vol" is a fantasy
You must be ignorant of extensive discussions of this phrase in earlier editions of this thread. The phrase is used in the very last "Finding" of the first interim report, that is an unfortunate collection of ambiguous, inexact descriptions of the impact conditions. (The english translation is even worse). The BEA has evidently recognized their error, and has carefully rephrased it in impeccable engineering language in the second interim report:
L’examen de l’ensemble des débris confirme que l’avion a heurté la surface de l’eau avec une assiette positive, une faible inclinaison et avec une vitesse verticale importante.
I frankly fail to see the merit of continuing to refer to the poorly worded first edition, since it has been corrected.
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Old 3rd May 2011, 21:47
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It is important that "heading" and "en passage", not be included, they are misleading, notwithstanding the "modification" of the BEA's language. It was not a correction, merely a quiet abandonment of a gross error.
 
Old 3rd May 2011, 21:49
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Unknown horizontal trajectory

Ok!

Debris field shape at sea floor not related to a/c fall trajectory!

Good question on engine #2. Where it is?

I want to see also where is right wing, the right main L/G, etc.
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Old 3rd May 2011, 21:54
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It cannot be far, for the aircraft hit the water's surface intact.
 
Old 3rd May 2011, 22:02
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Words or gross error

HazelNuts39,

I commented bearfoil post and his specific line on "ligne de vol"

I will analyze this issue in the BEA reports trying to see if was "words" (terminology) or "conceptual errors" or occurred from (an)other reason(s).

Will do it ASAP.

Thanks for clarifying an important issue.
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Old 3rd May 2011, 22:13
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Bearfoil;
... the aircraft hit the water's surface intact.
.. and thank you for
It was not a correction, merely a quiet abandonment of a gross error.
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Old 3rd May 2011, 22:15
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Originally Posted by bearfoil View Post
RR NDB

Yes, easy to say, but it brings up a flaw in the Search strategy. At the outset, and as early as possible, the BEA trumpeted, "Intact at Impact". Then the reliance was on ACARS to entertain "Continued Flight" into weather, and all manner of Radar excuses. This is how it must be read. A "Search" must include ALL areas that are possible, even those that fly in the face of the "Reputation" of what are arguably collateral players, pilots, union, Thales, AB, etc.
[...]
Keeping 10nm away from LKP is (was) inexcusable, boneheaded, and incompetent.
Where are you getting this from ?? Who kept away from LKP and when ?

From what I've read, the first two search phases were all covering zones "centered on LKP". Phase 1 mostly looked for pinger signals, plus (as I read it) some additional Phase 2 ROV searches to cover areas where they'd run out of time on Phase 1. In addition, they did complete bathymetry of the area to inform future searches - 40NM circle, where ? - centered on LKP, again.

Only in Phase 3 did they do something different - only after having failed to find anything with a general search centered on LKP, they searched an area calculated from drift analysis of the wreckage. That turned out to be wrong - but with so many variables and uncertainties and the delay in finding the floating wreckage, that's not really suprising. But surely it was worth trying?

Phase 4 went back to square 1 effectively, looking for wreckage rather than pingers, and starting from... - LKP, again.


So in what way were they ignoring or avoiding LKP or assuming the plane flew on for longer ? They centered everything on LKP!

Why again is the DFDR inside the fuselage and not the Vertical Stabiliser ??
Don't they (VS) have a habit of falling off in flight ?

More seriously, it's because some time ago someone decided that tail was most survivable place (probably is in most accidents - not this one though), and they need to be somewhere accessible for maintenance I believe. Someone also decided there should only be one recorder (of each type), very well protected. Probably right in the days of bulky and expensive foil and tape, maybe not now, when gigabytes of solid state memory is a few $ and smaller than a fingernail.

We could probably all do a better job of designing a recorder system now, with hindsight and infinite retrofit budget, but lets not forget that the current CVR/FDR system actually has a very good recovery rate when you consider the number of possible ways to crash a plane.

[ ULB failure in this case definitely needs looking at - doesn't look to be any difficult terrain reason for failure as was suggested before ]
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Old 3rd May 2011, 22:22
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VS acting as antenna and perhaps the whole empennage

JD-EE,

Any metal inside the Tail Fin will act as an antenna (considering you are coupling it in a "shunt feed" approach)

Even the VOR (DUAL) antenna coax cable (outer shield) located near tail fin tip would radiate and (receive signals).

I don´t know the HF behavior of the material EADS used in VS. And i am neglecting it´s influence.

And for sure there are other metallic parts in the A/B VS newer planes than just VOR (DUAL) cable.

Perhaps ALSO the HS is "in the antenna".

I suspect the antenna is actually the whole Empennage.

Therefore presenting some "horizontal polarization"

Later we will talk about this specific issue.

Rgds,
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Old 3rd May 2011, 22:32
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Phases

infrequentflyer789,

Look:





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