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AF 447 Search to resume (part2)

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AF 447 Search to resume (part2)

Old 28th Apr 2011, 09:27
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Looking at the deformed orange box I was wondering how it is exactly installed in the A330 (where exactly and in which orientation) and if we can derive something from the damage pattern about direction of forces applied.

Have we touched that somewhere and I have simply overseen/forgot it ?
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Old 28th Apr 2011, 09:35
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Dumb insensitive British press at its worst

Robot submarines find part of Air France jet black box 13,000ft under Atlantic | Mail Online

[edit]Report now updated to refer to bodies of "passengers" and not "survivors"

Last edited by sensor_validation; 29th Apr 2011 at 13:12.
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Old 28th Apr 2011, 09:47
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Originally Posted by Machinbird
If the "beer can" is much denser than the chassis, they should look back to the East of the Chassis location to have a hope of finding it.

You're assuming the crash site (impact with surface) being east of the wreckage... LKP being east doesn't mean -IMO- that the plane impacted water on the same side... Therefore, the memory "can beer" may lie everywhere around.
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Old 28th Apr 2011, 09:56
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@JD-EE

I fail to see a loop.

It looks very much like a small (semi) vertical monopole planted on the virtual ground (the aircraft).
At about 9 feet its resonance is around 26 MHz, (radiation) efficiency of the order of 1%, a set up similar to an HF whip on a car.
The location allows for a rail-kind of radiator, it helps to handle the many Amperes (not far from 100 ?) and flattens the bandwidth behavior (no need to retune when staying within a same frequency band).
Radiation would be pretty well omnidirectional with a peak towards the front (more return current).

Worth a different thread perhaps.

Kalimera
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Old 28th Apr 2011, 10:22
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sensor validation,
I am no fan of the "hero pilot steers stricken plane away from school" style of reporting we often see, but I have looked at the article you linked to and cannot find an explanation for the reasonably factual content it contained deserving such lambasting, am I missing something ?
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Old 28th Apr 2011, 10:25
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strange image

Dear sirs,

I definitely donīt identify with the conspiratory fringe. But I find the image of the box found at the bottom strange.

Just have a look, in the original image, at the region I have marked here.



If you amplify that region with Paint, youīll see that the texture of the pixels are different from the rest of the image. It seems to me like someone tinkered with the image.



But I really canīt think about a reason for that.

Also, if it really is an altered image, this could be the reason why BEA decided to distribute the photo popping up from the monitor (as someone observed sooner). Looking at the monitor conveys the feeling that we are witnessing the real workings of the ROV, not that we are really looking to an altered image.

Last edited by Centrosphere; 28th Apr 2011 at 10:34. Reason: additional information added.
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Old 28th Apr 2011, 10:31
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From pictures of DFDRs I find it remarkable that the pinger's (ULB) attachment to the memory unit (CSMU) in the Honeywell SSDFDR seems to be a rather lightweight affair. (The ULB is the smaller "can" affixed to the end of the memory unit.)

FAA regulations prescribe that the ULB shall be "securely attached" to the memory module, which is quite logical.

Each recorder container must:
(1) Be either bright orange or bright yellow;
(2) Have reflective tape affixed to its external surface to facilitate its location under water; and
(3) Have an underwater locating device, when required by the operating rules of this chapter, on or
adjacent to the container, which is secured in such a manner, that they are not likely to be
separated during crash impact
.
Looking at the debris in this case I would not be surprised if the ULB has separated from the memory unit. That will probably not affect the chances of finding the memory unit now, but it may have contributed to the failure of the initial search operations.
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Old 28th Apr 2011, 10:41
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Live imagery?

"Also, if it really is an altered image, this could be the reason why BEA decided to distribute the photo popping up from the monitor (as someone observed sooner). Looking at the monitor conveys the feeling that we are witnessing the real workings of the ROV, not that we are really looking to an altered image."

If i thought that i was watching live imagery from the ROV then i would expect to see at least depth, heading and speed info on the screen.
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Old 28th Apr 2011, 10:43
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Catplaystation,

I think "sensor validation" was shacked by this phrase:

"The latest retrieval operation started after cameras pinpointed wreckage and the bodies of survivors some 4000 metres (13,000 feet) down."

"Bodies of survivors" donīt seems a sensible description of what the expedition found at the bottom...
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Old 28th Apr 2011, 10:46
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Centrosphere

I definitely donīt identify with the conspiratory fringe. But I find the image of the box found at the bottom strange.

Just have a look, in the original image, at the region I have marked here. If you amplify that region with Paint, youīll see that the texture of the pixels are different from the rest of the image. It seems to me like someone tinkered with the image.

But I really canīt think about a reason for that.
To me it looks like the area you point out is the middle of the picture. It also appears to be (quite logically) the area where the two main searchlight beams converge. This implies that all shadow areas "vanish" in that particular area of the picture, making the surface features appear very low contrast and featureless.
Towards the sides of the picture the shadows appear different as you can see the sharp shadows from each individual searchlight beam. The twin beams also make the shadow of the DFDR chassis look rather odd.

A somewhat similar optical effect appears when you look from your airplane exactly down-sun i.e. towards the airplane shadow. The shadow is surrounded by a light "halo" with very low contrast.
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Old 28th Apr 2011, 10:47
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Nice point, cura.

I think youīre right if you only consider people acknowledgeable about rescue missions using ROVīs, not the general population.

But I really can be reading too much here.
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Old 28th Apr 2011, 10:55
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snowfalcon2,

Actually I have seen this effect incountable times when flying. I think there is even a name to it: "pilotīs glory".

But I used to think that this effect is caused by backscattering light, what donīt seems quite be the case here. In fact the region is less, not more, bright than the rest of the image, or parts of the image at least.

Last edited by Centrosphere; 28th Apr 2011 at 10:56. Reason: correction of text
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Old 28th Apr 2011, 11:13
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Henra

The picture you are looking for is in Part 1 post #3050 provided by Machaca.

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Old 28th Apr 2011, 11:26
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centrosphere

Maybe.
Looking more closely at the lighting, it appears that the left searchlight has a bluer light than the right one and it also appears to be brighter. This may have an effect on the perception.

There are several optical effects that may play a role in this picture. The "vanishing of shadows" is one that lowers the contrast of the mid picture area. Another possible effect is the Gloria effect that may cause the areas surrounding the middle area to appear brighter, i.e. the effect you comment on.
Finally, backscattering (or Heiligenschein) may also play a role. But I believe that this effect is dependent on the surface characteristics of the subject. For example dewy grass often makes this visible, but in this picture we don't have such features.

Of course it's also entirely possible that, for example, there were some human remains on the seabed at that spot and BEA did not want to show those to the world. But lighting effects are IMO more likely.
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Old 28th Apr 2011, 11:35
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possible explainations

Possible explainations could be;
1. image is from the 'non-flying' camera
2. image is a still shot extracted after recovery
3. ROV not being flown but following a predetermined search pattern

With regard to the lighting effects, the ROV has a variable intensity lighting system, perhaps the port light was set at a higher intensity than the stbd one.
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Old 28th Apr 2011, 11:55
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Cool

Hi,

Black boxes:
In my opinion this design standard should undergo a great improvement.
From concept .. the black boxes did not change much.
Techniques to store data have improved (following developments with other techniques such as computer .. .. .. etc) .. but not their container .. or the system that allows to locate them.
In fact, these black boxes are considered a mandatory accessory by laws and therefore and so long they are present and in working condition ... everyone is happy and we can say that once everything is done to improve safety ....
When the accident occurs and the black boxes are not found .. or found after long searches (but what is the pinger?) and in addition they are deteriorated .. he is sure someone (authorities) to say that the black boxes were OK .. well maintained .. but the shock of the accident was very violent .. etc. ....
But everyone know that a plane that crashed into the ground or water .. suffer (mostly) a big shock ....
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Old 28th Apr 2011, 11:57
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Snowfalcon2,

I really believe the "bluer light" to be an effect due to the water. I see no reason to use two different colors in the lighting apparatus. Phoenix International site only gives this information concerning the lighting system of the Remora 6000:

4 x Remote Ocean Systems 250 watt lights ( variable-intensity )

Actually, I have searched for other photos of the sea bottom taken from ROVīs. I couldnīt find many decent pictures, but the ones I found lack this effect. Please look at this one, from a submarine archeological site:

Woods Hole Oceanographic Institution(WHOI) : Archaeology in Deep Water

"Of course it's also entirely possible that, for example, there were some human remains on the seabed at that spot and BEA did not want to show those to the world."

Yes, I was considering this possibility the more likely, if this is really an alteration of the photo and not a natural effect.
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Old 28th Apr 2011, 11:58
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[/quote]
Originally Posted by Machinbird
If the "beer can" is much denser than the chassis, they should look back to the East of the Chassis location to have a hope of finding it.

Quote:AlphaZuluRomeo

You're assuming the crash site (impact with surface) being east of the wreckage... LKP being east doesn't mean -IMO- that the plane impacted water on the same side... Therefore, the memory "can beer" may lie everywhere around.
In Part 1 of this thread we discussed wreckage distribution and how it had been influenced by a slow moving current from E to W. You must not have been paying attention then and missed an opportunity to give us your 2 cents in a timely fashion. Do you have a different theory of wreckage distribution? Lets hear it.
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Old 28th Apr 2011, 12:05
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Originally Posted by susu42
Henra

The picture you are looking for is in Part 1 post #3050 provided by Machaca.
Hi Susu42,

Thanks a lot !
Now that I see it I remember having seen it before

If I see it correctly ithe DFDR is mounted vertically.
With the tiny mounts of the CSMU it is clear why it tore off the rest of the DFDR upon impact.
On the other hand the deformation of the base plate is somewhat strange given the orientation shown in this picture.
@Machca (if you read it): Do you know if all DFDR's are mounted that way on A330's, i.e. the one in AF447 as well?
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Old 28th Apr 2011, 12:18
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Centrosphere,

Indeed, I missed that one.
A bit like a joke we told as children,
" a plane crashes exactly on the border of Russia & Finland, where do they bury the survivors" ? ? or something like that, well, you get the meaning I am sure.
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