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AF 447 Search to resume (part2)

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AF 447 Search to resume (part2)

Old 12th May 2011, 08:37
  #1201 (permalink)  
 
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Recorders arrived at the BEA this morning

Images were shown some minutes ago
Reminder . BEA press conference at 10h00 LT 0800Z.
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Old 12th May 2011, 10:09
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Press conference

Alain Bouillard, in charge of the AF447 investigation said:
Are recovered:
All seats of the cockpit ( including JS), both Captain and F/O sticks
(Angle of)Incidence probes, broken but "behind" is OK
Cockpit door
Meuble (furniture) 800VU

EEC recovered or located
Engines cowlings

A presentation of already recovered parts was shown. I could see written
THS jackscrew, I believe.

I think and hope that BEA will put some docs on line soon.
The "Ile de Sein" will sail to Dakar tomorrow for crew relief. And then will go back on the scene.
Mr Bouillard said that the cockpit might be raised to surface today.
For the time being no indications have been given about the bodies.
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Old 12th May 2011, 10:18
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BEA

Hi,

I missed the video recording of the wreckage maping!
- Both engine position is confirmed as I pictured them before (no numbering in this map).
- The cockpit is at the West end of the main debris field (all seats recovered, with sticks and various parts).
- The only big piece of wreckage lying East of the engines is one of the MLG (it is not with wing parts as pictured before)
I'm trying to recover this map now.

Last edited by takata; 12th May 2011 at 10:39.
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Old 12th May 2011, 11:53
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Ratherbeflying,

Retrieval of bodies in this state can be very hard on those involved, and it's likely completely impossible to treat such remains in a dignified manner.
With all due respect to the relatives of the pax and crew, the need to mourn the dead isn´t the only factor playing here.

I bet a lot of people wants the bodies to establish the right to have a claim against AB and AF. Brazilian law, for example, is a little bit tricky in this aspect, although the brazilian Minister of Justice tried to assure the relatives that the lack of bodies would not be a problem.
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Old 12th May 2011, 12:04
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On the bodys there is a very good chance that they simply explode if you raise them from their 400bar environment and assume the gaseous decay by the time now. Thats an extreme burdeon on all people involved. And most of forensic information will be lost with this process.
IMHO it was a wise decision from the courts to leave them where they are.
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Old 12th May 2011, 12:37
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They have had plenty of time to design, build, test and certify such a system if they were half way serious. You have to ask, why haven't they ?
Goodness me... where are you coming from
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Old 12th May 2011, 12:53
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In many countries, death certificates can only be given with actual physical proof of death. Otherwise, very long "washout" periods have to be met. It can turn out to be administrative nightmares for families. So, to recover and identify bodies has its importance.
In France, it takes up to ten years to be declared officially "missing". Although, I dont know if it applies also for plane crashes .
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Old 12th May 2011, 13:07
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New PDF on BEA website.

http://www.bea.aero/fr/enquetes/vol....n12mai2011.pdf (in French) page 10 has a new diagram with locations of major parts.
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Old 12th May 2011, 13:09
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on a personal note if it was my child for instace that was killed in this accident i would demand to try have their remains recovered not matter what so i could bring them back home to lay to rest and some where the family could go to mourne when they felt the need to .. bit impossible to get to the middle of the atlantic every day ,its very easy to say leave them there ,if it where your family what would you be saying?
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Old 12th May 2011, 13:30
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Originally Posted by rh200
With todays computers I would be surprised if you couldn't easily process in real time. After all you can easily fft and square (power spectrum) 100 MHz bandwidth nyquist sample data in real time. Hence I would have thought for these trivial bandwidths it would be a walk in the park, some one would need to work out the flops.
Um, maybe. For a 10 second average you'd need to process in a really rough round number 100 sets of convoluted data and present it for eyeballs. If you try to "detect it" you need to synchronize with it and multiply it by an estimate of the signal. You'd have to do this for about 100 to 1000 different time estimates for best results. (Um, at a rough guess intuition is suggesting on the order of 500 to 700 to have no more than 1dB loss. Of course, many of them might cross threshold. But there will be a distinct peak that might be worth the effort to get. 100 would be too few. And 200 cuts your summing advantage by half.) So that's say 500 time alignments on 100 different frequencies for 50,000 sets of calculations with a sample rate of at least 8 ksps on a down converted slice of spectrum. That's pushing one single CPU.

I'd go for the Mark 1 eyeball method with only 100 different waterfalls to watch - if I could find enough eyeballs to make it work.

Post processing the data would vastly reduce instantaneous load by spreading it over time - if people were patient enough.

(The 100 frequencies estimate came from trying to sum over 10 seconds. 2 Hz of seconds gives a phase error of 7200 degrees. You want it down under maybe 30. So my 100 is rather small compared to what you'd want. The ping type signal is just not very nice for digital processing.)
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Old 12th May 2011, 13:35
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The items marked in red on the new chart seem to correspond with the listing of the items recovered given by the BEA.
Can we assume that the two bodies recovered were the pilots as why else were their seats recovered?
I wonder why the engine fan cases are marked in blue?
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Old 12th May 2011, 13:37
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Grity:

if you need stady cruise for your intresting experiments, did you think it can be possible to create a system which can read the birds noise and extract the speed (or altitude)(or even the change of this parameters) while it compared the currend sound profil with a databank of sounds ?
What you need to know is at least one significant data point (be it altitude OR speed) and have a set of profiles over a reasonable range (something like 20kt speed increments, or 1000ft altitude steps), and perform a best match, which in my case would be least residual... the profile subtraction that resolved to the least residual would give you ballpark parameters.

The reason you need to know at least one key parameter is due to the fact that cruise at FL350 M0.79 can easily look the same as cruise at FL380 at M0.76 for example, at least as far as noise profile is concerned. If you had a LOT of data samples to work with you could refine this, but generally I'm lucky to have 3 or 4 samples of cruise at various specific alt/speed combinations, not the 10's of samples that would really be needed.

As for a next generation pinger design, it would make a lot of sense if it were a transponder design - from what I can find sprinkled around the web, this should result in approximately double or better the range being possible.
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Old 12th May 2011, 13:48
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GarageYears, if you know the cockpit noise has specific repetitive characteristics you can find them in the sample you're working with and subtract them out. The remainder would be the somewhat more random speech products. Pulling out the broadband random background is a different ballgame. It can make some difference. But it's not huge.

For example, in the really old days aircraft radios had dynamotors. They had a characteristic whine that could be filtered out. You can also filter out a lot of the low frequency sounds and still hear speech remarkably clearly. (Bose noise canceling headsets anybody?) So aircraft 400 Hz whine and things like that can be neatly removed along with the low frequency rush leaving very clear speech. I don't think that's going to help with already band filtered 36kHz to 39kHz audio.

In the pinger search most of the background noise is short bursts of coherent noise containing a series of short bursts of signal. Filtering out the whale song to leave the signal would be "interesting".
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Old 12th May 2011, 14:00
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gums, I discussed a constant signal of lowered power with pseudorandom noise, PRN, modulation. (I did not state it in exactly those sorts of terms. I tried to phrase it so non-EEs could dig what I said.) GPS is a good example. And I'd postulate a chipping rate (PRN bit rate) around 1/10th to 1/2 the nominal 37.5 kHz. Once doing that I'd use crystal control even if it's a "floor sweeping" crystal with very wide tolerance. (200 parts per million.) You'd have to acquire time and frequency, of course. The acquisition problem may indicate a lower chipping rate. (And my jargon may be a tad out of date. Those are the terms we used in the department at Rockwell where I did this sort of stuff for over a decade.)

{^_^}
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Old 12th May 2011, 14:08
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Tubby, a reasonable assumption given what Squawk Ident posted. Perhaps the cowlings are in blue because they are being recovered before Ile de Sein goes to Dakar.

Is the plan to offload the bigger recovered pieces in Dakar?
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Old 12th May 2011, 14:10
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auv-ee, I appreciate your effort. Discussion here has me questioning the "short detection range" that took place soon after the accident while the pinger search was on. Indications seem to be the range should have been much greater than the 1700 meters that sticks in my memory.

{^_^}
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Old 12th May 2011, 14:14
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Debris Field Map

Debris Field Map:

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Old 12th May 2011, 14:20
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GarageYears - I might be tempted to see what broke before running off and designing a better spring for the mousetrap that actually broke it's wooden base.

{o.o}
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Old 12th May 2011, 14:21
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@tubby linton
Can we assume that the two bodies recovered were the pilots as why else were their seats recovered?
That crossed my mind too, and I think it is a reasonable assumption since we know two bodies have been recovered with seats, and that two (pilots) seats were recovered. It also fits with the court ruling on body recovery - I had wondered why they proceeded before the ruling (but probably after asking for it). It all makes sense if they recovered the pilots (in case they can get any medical evidence for investigation) but asked the court to rule on the pax + cabin crew bodies.

@kit344
http://www.bea.aero/fr/enquetes/vol....n12mai2011.pdf (in French) page 10 has a new diagram with locations of major parts.
Many thanks for spotting that, also many thanks to takata for excellent previous work from the videos - now redundant, but you did get the engine numbers right.

@Centrosphere
I bet a lot of people wants the bodies to establish the right to have a claim against AB and AF. Brazilian law, for example, is a little bit tricky in this aspect,
Everyone on the flight has already been declared dead by an official accident investigation. Even if that isn't recognised in Brazil, then there will be jurisdictions where it is, and AF & AB have a lot of presence around the world - plenty of places to sue them.

Also, as well as the serious practical considerations in raising the bodies, there is a big problem with the wishes of the relatives. Some want them left undisturbed, some want them raised, but clear identification is probably only possible after retrival (and maybe not even then). Whatever they do they cannot meet everyone's wishes.
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Old 12th May 2011, 14:26
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Tubby

The fan casing is part of the engine, the part that was torn away just forward of the fan frame. The remaining part of the fan casing where the fan frame struts attach is visible in the photo of the recovered engine.

TD
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