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-   -   AF 447 Search to resume (part2) (https://www.pprune.org/tech-log/449639-af-447-search-resume-part2.html)

glad rag 27th Apr 2011 19:05

777fly yes I think that we should try and remain upbeat for the moment, still a bit of a blow though.

I think they will eventually find it, as you said it hasn't sunk into the silt at all.

MountainWest 27th Apr 2011 19:07

Rear-View Analysts . . .
 
Now that AF447 has been located it is easy to ask: "Why didn't you just look there in the first place and save all that time, trouble and money?" Regardless of when or where or whether the wreckage was found, there were bound to be accusations of "too close, too far, too much, too soon, too complete . . . " If the problem had been easy it would have been solved a long time ago.

It is good the authorities have involved recovery resources from multiple agencies and nationalities. Regardless of the outcome of the investigation there will be conspiracy accusations. Anomaly or even completeness will be seen by some as "evidence" of a coverup. The more BEA involve independent participants, the less likely the accusations are to resonate with the public.

If the problem had been easy it would have been solved a long time ago.

jcjeant 27th Apr 2011 19:19

Hi,

I hope .. the families will have now the answers to their questions .....

Google Vertaling

Original:
Réunion du 5 octobre 2010 au ministère des transports | BEA

SaturnV 27th Apr 2011 19:25

I am a bit confused by this discovery. I thought that the Alucia had photomapped the entire wreckage area (thousands of photos) and no sign of either recorder, and thus the supposition was they were still in the tail.

Did the Alucia miss this recorder, or is it now being seen because the Ile de Sein moved a piece of wreckage that was obscuring it?

Chris Scott 27th Apr 2011 19:27

Quote from 777fly:
"It is encouraging that the FDR module, although missing the CSMU, is not buried in silt to any extent. I do not see any footprints or scrape marks around the the FDR housing, so not much for any conspiracy theorists to go on."

I wonder at wahat stage the "module memoire" broke away from what they call the "chassis". At sea-level impact or when the chassis hit the sea bed?

Seem to remember someone came up with a suggestion on this thread that a long streamer might be attached to these modules in the future...

AlphaZuluRomeo 27th Apr 2011 19:43

@ SaturnV : IIRC Alucia vehicle glided "far" (~10-15m) above the sea bed.

Look at the picture, imagine what you would see from this same part (recorder casing) on a pic taken vertically from 10m high ?
I'm not sure if the previous pics (phase 4) were in colours ? If B/W pics, it's even harder to notice that part as "interesting".

@ Chris Scott
"Il s'est désolidarisé sans doute sous l'effet de l'impact" avec la surface de l'eau, a expliqué à l'AFP le directeur du BEA, Jean-Paul Troadec
quote from Le Monde (here)
Rough translation = the BEA director thinks the memory module broke apart when the plane impacted water.

snowfalcon2 27th Apr 2011 19:46

deSitter
 

Recorder but no memory module - isn't this unprecedented??
No. In the ET409 accident, i.e. the Ethiopian B737 which came down in the sea after takeoff from Beirut on 25 Jan 2010, the CVR memory module had separated from the chassis. It was reportedly found at a later stage.

Machinbird 27th Apr 2011 20:29


I wonder at what stage the "module memoire" broke away from what they call the "chassis". At sea-level impact or when the chassis hit the sea bed?

No. In the ET409 accident, i.e. the Ethiopian B737 which came down in the sea after takeoff from Beirut on 25 Jan 2010, the CVR memory module had separated from the chassis. It was reportedly found at a later stage.
Is it just me, or does this seem like a Delta Sierra design for any crash recorder? It might make sense if there were 20 of these memory units scattered about the aircraft, all with mirrored copies of the data, but like this? Why have a big orange painted box of no value to the investigation, and a small coke can containing the "crown jewels" perched on a shelf of the large box where it can be knocked off the "shelf" and make its own trip to the bottom? If the memory module is not buried in the silt under the big box, you can bet it broke loose at the water interface transition.:{ And from the second quote, it appears they already had one object lesson.:mad:.
And this accident was probably only ~ 1/40th of the peak possible crash energy!!!

KTVaughan 27th Apr 2011 20:34

loss of pinger
 
If the FDR is that beat up, this might explain why the pinger was never detected...........

snowfalcon2 27th Apr 2011 20:44

If my memory is correct, the pinger (locator beacon) is attached to the memory module rather than the recorder chassis. (Applies to both FDR and CVR of modern design).

It would be a logical design choice, but it would also imply that the pinger power supply batteries are housed in the same module, making it a comparatively heavy item which is more likely to drop straight down to the seabed than, for example, other parts that are mostly aluminium sheet construction.

The BEA must have all this already figured out, of course. Hopefully the memory module and the CVR are soon found.

gums 27th Apr 2011 21:06

Salute!

As promised, I shall refrain from speculation on "causes" and "design" of the plane.

OTOH, fer jeeez friggin' sake!!!!! The "memory" is not encased in a stainless steel/titanium "crash survivable" container - like the the DFDR itself, and is attached to the OUTSIDE of the neat, orange qizmo!?! BEAM ME UP!!!!

Oh well, we had really good data from the Columbia breakup, and that sucker went thru a lot more heating and forces than the AF jet. Had some great stuff from the Buffalo loss of control crash. Decent stuff from the Airbus back in 2001. Hmmm.

And what is that beer can doofer at 1 o'clock in the pic?

RR_NDB 27th Apr 2011 21:07

Highly optimized HF antenna
 
Hi, Graybeard

I will design ASAP an HF antenna based in ideas developed during our discussions.

I will field test it in my RV where i currently use a moving pole plus trailing wire with SUPERB performance, ranging from 1.5 ~ 18 MHz rated 500 W rms. I operate it with a manual tuner assembled with the best material (MIL STD) used in old birds.

But the moving and the height above the motor home presents an extra load to my "crew" and we hit telephone wires and trees sometimes.

Now we must concentrate in the AF447 issue that will be heating up with the recent findings.

Thanks for the motivation you gave me to further study an issue i was interested since 1965 and is one of my passions. HF comm.

sensor_validation 27th Apr 2011 21:19


Originally Posted by gums (Post 6415935)
And what is that beer can doofer at 1 o'clock in the pic?

Its the pitot tube sticking out of the bed at 12-O'Clock (with shadow) that leaps out at me...

http://www.bea.aero/fr/enquetes/vol....s.fdr.site.jpg

jcjeant 27th Apr 2011 21:40

Hi,

tube .. maybe ... but pitot ???????
Notice the very good physical state of the box ! .. no evident corrosion .. etc ...
That's a good premise for the other items that will be recovered as evidences for investigation.

SaturnV 27th Apr 2011 22:32

Why is the memory unit fastened outside the chassis (storage box)? Surely, there must be a design rationale for doing this.

I assume the same design for the CVR as well.

So we have a description of a tail section supposedly sufficiently intact that the recorders are first thought to be inside that section. Now, there is at least one recorder that apparently separated on impact, and the impact forces also dislodged the memory module from its external mounting.

Only saving grace at this point is that the plane settled on a flat plain, and not on the slope of a crevasse.

Flight Safety 27th Apr 2011 22:52

Upon examination of the Honeywell link that PJ2 provided, it appears the crash survivable memory unit (CSMU) and the DFDR chassis are designed to separate. The Underwater Locator Beacon (ULB) is attached to the CSMU, and thus designed to stay with that unit in the event of chassis separation.

TOM57 27th Apr 2011 23:00

BEA says that the area where the plane was found had been researched in the early phases by sonar. Nothing was detected then, and that is why they had privileged other sectors in later searches.
In French:
Les recherches de détection acoustique des balises installées sur l’avion, et
devant émettre un signal pendant 30 jours au moins, ont donc eu pour objet
d’explorer en priorité la zone se trouvant le long de la trajectoire prévue de l’avion
et, en fonction du temps et des ressources disponibles, la plus grande surface
possible du Cercle. La zone où l’épave a été découverte avait donc bien été
explorée par ce moyen, sans détecter les balises. Les raisons de cette non détection

vont maintenant être recherchées.
http://www.bea.aero/fr/enquetes/vol....la.phase.4.pdf

It is said that they don't know why the pingers where not detected and will have to look in to this.

Thanks for this great thread!

ChristiaanJ 27th Apr 2011 23:01

gums,
The memory module IS supposed to be "crash survivable" on its own. Whether it parting company with the rest of the recorder assembly was also sufficiently considered is now an open question....

mm43 27th Apr 2011 23:08

It appears that the mounting plate for the CSMU on the DFDR chassis has suffered some deformation, and there is stress indication which looks like the CSMU securing bolts have been dragged through the mounting plate.

The CSMU/ULB will not be too far away, i.e. the combo will be a straight down unit, but mass/volume means their landing will not have been soft. The silty bottom indicates to me that some technique other than visual will be needed to find them

ChristiaanJ 27th Apr 2011 23:28


Originally Posted by deSitter (Post 6415727)
And to ChristaanJ, I surely hope you have better girl-spotting skills than planes :) The A330 is a catfish - the 777 is a horizontal spacecraft!

No trouble with girl-spotting, LOL.
And many many years ago I did win a local plane spotting competition, but that was still in the days where there was a difference between a Comet and a 707 or a DC-8, or between a Sabre and a Hunter....


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