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AF 447 Search to resume (part2)

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AF 447 Search to resume (part2)

Old 28th Apr 2011, 19:33
  #281 (permalink)  
 
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But in this picture there are at least two light sources, one on each side of the lens.
Too simple!

The image we are looking at is a screen shot of another screen. There are lighting sources external to the monitor, and I suspect that the loss of contrast in the area above the SSFDR chassis is an artifact caused by numerous things, including color temperature, reflection, and external camera automatic focus and aperture issues. Nothing more.
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Old 28th Apr 2011, 19:38
  #282 (permalink)  
 
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snowfalcon2,

"In the middle of the picture both lamps have equal brightness and so each lamp cancels out the shadow cast by the second lamp (unless the feature is big enough so that the lamps create two overlapping shadows). The result is a low contrast area."

Clever explanation, but...why this would only happen at the central region of the image and not along the vertical axis of the photo?
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Old 28th Apr 2011, 19:43
  #283 (permalink)  
 
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mm43,

Lurking at this forum for months, I developed some respect for your opinions, but I have to disagree now. It seems too ad hoc. Alas, you can see a reflexion at the left superior border of the monitor. I think we could rule out the interference of some other light source in the picture.

I´m sure that in being so assertive some people here will begin to suspect that I have some hidden agenda, but I assure you that I have not an axe to grind. It only happens that I´m a guy that likes advocating for the Devil!

I have no reason to believe that someone would tinker with the image, but still I can´t make myself to believe this image is normal. Personally, I tend to agree with the guy that raised the possibility of "censorship" in the best interest of the families of the dead.

Last edited by Centrosphere; 28th Apr 2011 at 19:50. Reason: complementing the post
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Old 28th Apr 2011, 19:52
  #284 (permalink)  
 
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A pure SLF






The left hand bottom corner is into the silt a little. Could not the memory module still be there and buried??
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Old 28th Apr 2011, 20:10
  #285 (permalink)  
 
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How quickly this thread wanders off. And when it does then all sorts of inane comments are posted. MM43 has the most likely reason as to the differences in the picture. Cameras only record according to their settings. No cover up imo or anything sinister. Unless someone comes up with the suggestion that the media is down there trawling through the debris and has taken the module. OMG.
Maybe someone should go back to lurking.....
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Old 28th Apr 2011, 20:46
  #286 (permalink)  
 
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Promani,

I really don´t see any reason for your agressive comment. I argue in good faith and respect the other commenters here. More important, I have made clear that I don´t give credit to any conspiratory theory, or doubt that the people in charge of the investigation are doing their best.

If you are more interested in other aspects of this issue, that´s fine to me, but please note that this forum has plenty of space for that, with no need of being rude to other people. Unless, of course, you are a troll or worse.

Please recant or I´ll be forced to denounce your bullying behaviour to the moderators.
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Old 28th Apr 2011, 21:00
  #287 (permalink)  
 
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CSMU

Could not the memory module still be there and buried?
crippen,

I had the same feeling at the first time i did see the picture;

Would be fantastic. But BEA said NO:

Information, 27 April 2011
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Old 28th Apr 2011, 21:06
  #288 (permalink)  
 
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@ Machinbird (post #258)

Indeed I haven't seen the "wreckage distribution and how it had been influenced by a slow moving current from E to W" theories as a fact.
I was under the impression those they looked a little too much like a "guesswork", based on a single sonar picture without proved link between significant parts and the said sonar image, to pay attention to them.
I'm afraid I therefore have no different theory of wreckage distribution to offer...
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Old 28th Apr 2011, 21:14
  #289 (permalink)  
 
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Rocket shaped tube?

Any thoughts on what the white rocket shaped tube is on the right hand side of the monitor picture is?

Flare perhaps?

All opinions / inklings are more than welcome.
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Old 28th Apr 2011, 21:20
  #290 (permalink)  
 
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CSMU likely detached from Rack at sea surface crash

No way can the FDR have separated on impact with the seabed
Absolutely right!

Water surface for an stalled a/c at high sink rate is hard like soil.

And this crash into water destroyed the a/c.

As all of us can see the assembly of CSMU to the rack is not strong enough.
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Old 28th Apr 2011, 21:55
  #291 (permalink)  
 
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On texture and pixels:
I think the culprit of the 35+ posts is the suggestive ellipse drawn by Centrosphere in his post #246. Without that, the smooth area is about as wide as the DFDR 'box' but deeper than the ellipse suggests. In the nearly two years that this piece has been lying there, there must have been episodes of significant water currents across the 'abyssal plain'. The area we're looking at could well be the 'wind shadow' of the chassis, covered with finer material than the more exposed area's around it.

On impact forces:
What puzzles me is that the mounting platform of the CSMU is bent upwards, i.e. opposite to the inertia forces one would expect. That could be explained by the hydrodynamic forces acting either on the fuselage skin or directly on the DFDR mounting. But how was the CSMU then torn off its mountings?

Last edited by HazelNuts39; 28th Apr 2011 at 22:14.
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Old 28th Apr 2011, 22:05
  #292 (permalink)  
 
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FDR CVR

@crippen


Could not the memory module still be there and buried??
Yes, it looks like it could be there, but no doubt once it was turned over by the submersible, the truth was revealed. I think why we can see more of the PSU and drive electronics box in the photo is due to the crater surrounding the box, formed at the time of impact. The fact that there is no crater under the chassis which supports the memory section, suggests that the memory section is missing. The memory module, as can be seen from the fixings to the chassis, is designed to detach with minimal force in order to be free of any constraints and be able to survive becoming trapped and crushed amongst collapsing structures during high G impacts - hence the choice of spherical or cylindrical construction. However, like in any design, there are trade-offs, one of which is size, governed by the amount of fireproofing insulation needed to protect from high temperatures, and recognition - it's no good having a survivable device if it's too small to be found in wreckage. With the latter consideration in mind, the FAA standard for crash protected enclosures is to apply minimum dimensions for major axis.

For the elliptical cylinder example; the major axis (a), minor axis (b), and length (c) of the enclosure, must conform to the relationship:

a, b, c >= 2.0 inches
a + b + c >= 9.0 inches

The same applies for a rectangular shape, while for spherical shaped enclosures, the average radius must be => 3inches.

Given that the memory unit and the chassis have different shape form factors, I would be surprised if they arrived at the same location after a 4Km descent. Dependent on the CG & mass to vol, the cylinder/sphere is less likely to plane than the chassis (tumble maybe) and so will probably be found near heavy items from the empennage.
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Old 28th Apr 2011, 22:24
  #293 (permalink)  
 
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Small craters on the seabed are not likely to last long. However, one things underwater archaeologists have encountered is that submerged objects will often have areas around them dug out by the current. Basically, what happens is as the current encounters the object and is forced to go up over it, that causes the water right next to the object to become turbulent, which can push sediment away from the object. In archaeological terms, that allows later material to be deposited, which is why stratigraphy is of little use in underwater archaeology, even though it is of critical importance by land.

In terms of this situation, if there is a depression next to the recorder casing, it could indicate the direction in which the local currents tend to flow, and the depression was excavated by turbulent water from the current being forced over the recorder casing.
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Old 28th Apr 2011, 22:53
  #294 (permalink)  
 
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ushumgal;
In terms of this situation, if there is a depression next to the recorder casing, it could indicate the direction in which the local currents tend to flow, and the depression was excavated by turbulent water from the current being forced over the recorder casing.
Your analysis is correct.

However, in terms of the various photographs we have seen taken on the bottom, I would venture to say that current movement on the bottom is virtually nonexistent. Go back to the original photos and examine the left-hand MLG. You will note that the rear wheels touched down first and turned about 90 degrees, picking up some sediment from the bottom. The front wheels dug in, and there has been no sign of scouring in nearly two years.
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Old 28th Apr 2011, 23:07
  #295 (permalink)  
 
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BJ-Eng, thanks for your explanation on the design considerations.

I'm willing to wager however, that if the ultimate result of this search is two chassis units recovered, and nil memory modules, that design philosophy will be revisited, and likely revised.
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Old 29th Apr 2011, 00:16
  #296 (permalink)  
 
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Hi,

About the CSMU: do anybody knows the respective weights of the two parts?

About the "abnormal" spot on THE picture: could it be the result of Remora robot vertical thrusters: perhaps the robot "look at" the FDR from the other side before to take this picture and has disturbed the soil there?
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Old 29th Apr 2011, 00:25
  #297 (permalink)  
 
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I'm sure glad they didn't find the memory module first. I'd have lost out on a lot of entertainment.
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Old 29th Apr 2011, 00:27
  #298 (permalink)  
 
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Originally posted by HazelNuts39 ...

What puzzles me is that the mounting platform of the CSMU is bent upwards, i.e. opposite to the inertia forces one would expect.
I've puzzled about how the CSMU/ULB departed, and the only explanation I can come up with is:-
  • The 'g' forces at impact were complex, and the initial underside impact caused the the whole SSFDR to be punched up, and at the same time the mass of the CSMU tried to continue forward and to port, resulting in the securing bolts pulling then shearing off.
  • Perhaps a further look at the V/S clevis joints damage may help explain it.
That doesn't give a satisfactory explanation as to why the CSMU/ULB left its mount before the SSFDR, unless the tensile strength of the CSMU bolts were less than those of the SSFDR securing bolts.
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Old 29th Apr 2011, 00:40
  #299 (permalink)  
 
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Dependent on the CG & mass to vol, the cylinder/sphere is less likely to plane than the chassis (tumble maybe) and so will probably be found near heavy items from the empennage.
I don't think that mass or density play much here as do things lke drag coefficients (shape).

So to me from a shape factor, it looks like a minature engine.

At any rate it's more likely to be closer to the engines than anything else.

But since I'm not the guy looking for it, my opinon has little value

I once bought a 5 lb magnet for the sole purpose of recovering objects like this from the mud (I used to have it snapped to the underside of my "steel-case" desk and most couldn't even pull it loose.
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Old 29th Apr 2011, 00:51
  #300 (permalink)  
 
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Just to put this to bed, here is what happens when you get moon dust on a lens at f/16.

http://www.hq.nasa.gov/alsj/a12/AS12-46-6818HR.jpg
http://www.hq.nasa.gov/alsj/a12/AS12-46-6826HR.jpg
http://www.hq.nasa.gov/alsj/a12/AS12-46-6813HR.jpg

The camera is behind an optical window that can withstand immense pressure, meaning it is probably spherical. Since this protrudes from the underside of the ship, it's very possible that it can become smudged with whatever detritus it is maneuvering around in.

Really, has conspiracism just become a given fact of modern life? Sometimes a cigar is just a cigar.
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