Durée de vie des boites noires?

[SF260]

De plus je reste persuadé que l appareil n,a jamais impacté la surface intact

Dans l’hypothèse d'un "deep stall" (super stall) (cohérent avec un centrage très arrière), ça nous fait un impact intègre avec petit badin et assiette possiblement positive et très grosse Vz.

[DC8]

remonter une epave de 4000m il n'y a pas des masses d' entreprises capables , je n'en vois qu' une : smit tak ;http://www.smit.com/sitefactor/page.asp?pageID=115

Duree de vie des pingers : je me rapelle que les Russes ont retrouve grace au pinger le FDRs du 747 de la Korean abautu au large Sakhalin plus d' un an apres , mais a quelques centaines de metres de profondeur.

Le QAR par contre lui devrait resister assez longtemps a cette profondeur. Mais situe ou dans un A330 ? Sous le Cockpit?

[020OVC]

La réponse ?

D'un point de vue certification, il faut se référer aux TSO C123a et C124a qui eux-mêmes renvoient vers les normes EUROCAE (d'après ce qu'on peut lire) qui ne sont pas accessibles. J'ai trouvé cette présentation d'Honeywell qui reprend le 'cahier des charges' : http://www.ntsb.gov/Events/symp_vr_topt ... ofield.pdf

D'un point de vue pratique - l'avenir nous le dira.

[Lazio]

Merci pour le lien, en dernière diapo on devine :

en eau profonde 20000' durée 24h00
en eau salée 9ft 30 jours

En eau salée et en profondeur...peu de chance d'en retirer quelque chose

[Pégase-junior]

Je ne pense pas que 4 campagnes de recherches aient été financées sachant de toute façon que les CVR et DFDR seraient inexploitables, les enquêteurs ont un espoir raisonnable d'en sortir quelque chose.

[Bugs]

Ancien, SF260 et les autres, je suis d'accord avec vous mais n'oublions pas que dans cette affaire il y a deux volets principaux:

- Le volet technique (quelles ont été les défaillances, quelles pièces, dans quel ordre, bref, quelle est la chaine de causalité, technique et humaine.

- Le volet juridique: qui va payer et pour quelles raisons?

Alors, bien sur les enregistreurs de vol, les QUAR etc. permettrons de rationaliser et de préciser la chaine causale en question. Les pièces de l'épave aussi. Déja, sur l'impact, pas grand monde n'est d'accord: entier, pas entier, stall pas stall....

Gageons que plus on remontera de pièces plus on pourra affiner les hypothèses et les confronter aux éventuels paramètres de vol.
Vous remarquerez que je dis "on" afin de ne froisser personne...

Tout le monde peut aisément imaginer que les différents protagonistes de l'accident (AF, AI, Thalès et j'en oublie sûrement) n'ont pas envie de payer pour cet accident et ont encore moins envie de voir leur image associée au dit accident!

Alors, attendons, moins on fera de spéculations mieux on se portera...

Rappelez-vous cet avion de la Suiss je crois, qui s'était abîmé en mer après un feu lent à bord.... Rappelez-vous combien de temps, d'années, il a fallu aux enquêteurs (le NTSB je crois) pour que pièce par pièce, fils par fils, ils arrivent à la conclusion que c'étaient les écrans vidéos qui avaient créés une surchauffe du circuit électrique avec les conséquences tragiques que l'on sait....

Les faits, rien que les faits et les faits sont têtus!

[Laurent ALLIATA]

"tu ne me chercherais pas si tu ne m'avais pas déjà trouvé..."

[4Cs]

"tu ne me chercherais pas si tu ne m'avais pas déjà trouvé..."

Si tu as connaissance d'éléments que nous ignorons, merci de les partager...

[caveokay]

ce qui me surprend, si c'est vrai car vu et entendu à la télé , c'est que l'avion serait à 9 km de la dernière position connue
ils ont cherché où lors des trois premières campagnes

[4Cs]

Si tu regardes bien le diagramme des différentes phases de recherche, ils sont passés au-dessus lors de la première phase qui a immédiatement suivi le crash (10 juin - 10 juillet 2009) en recherche accoustique et l'ont frôlé lors de la phase 3 (2 avril - 24 mai 2010) avec sous-marin autonome et au sonar.

[Laurent ALLIATA]

Q&A: Will the mystery of Flight 447 be solved?



(CNN) -- Almost two years after Air France Flight 447 plunged into the southern Atlantic Ocean killing all 228 people aboard, search teams have located what they believe to be the actual wreck site.

Investigators have not yet determined what caused the airliner -- which was en route to Paris from Rio de Janeiro -- to crash. Large parts of the plane, including both flight recorders, have never been found, despite an extensive search operation that included a French navy submarine.



When did Flight 447 go down?



Flight 447 made its last contact with Brazil's Atlantic Control Center (ACC) at around 01:33 GMT on June 1, 2009, informing the center of the plane's position as it crossed the Atlantic.

Minister: Bodies found 2 years after air crash

Soon after, Brazil's air control contacted Dakar's control center in North Africa and reported that AF 447 was entering an area on its route known for constant bands of severe turbulence, officials said.

There was no further contact with the plane.



Why has it taken so long to find the wreckage?



2009: Air France jet fell vertically

2009: Plane's final moments

2009: What caused Air France crash?

Map: Air France Flight 447 The area where the Airbus A330 went down is in the mid-Atlantic -- two to four days for ships to reach from the nearest ports in Brazil or Senegal in West Africa.

The U.S. National Oceanic and Atmospheric Administration estimates the ocean depth in the area at 3,000 meters (about 9,840 feet) to 7,500 meters (24,600 feet). Brazilian officials have said the sea depth in the area is around 2,000 to 3,000 meters (6,562 to 9,842 feet).

The latest search covered a 46-mile (75-kilometer) radius around the last known position of Flight 447, investigators said.



According to the French Bureau d'Enquêtes et d'Analyses (BEA), the underwater terrain in this area is rough with underwater mountains and valleys.

"It is a mountain range as big as the Alps," David Learmount of Flight International told CNN. "There was always the possibility that the wreckage from the aircraft disappeared down a crevasse. This is not a flat-bottom environment like the North Sea is."

"Therefore it is an unprecedented search in terms of depth and sub-sea terrain."



What would happen to the wreckage at these depths?



The aircraft's "black box" data recorder -- a vital device for crash investigators which records any instructions sent to the aircraft's electronic systems -- remains missing but even if it is recovered, it is not certain whether it would still work, according to Learmount.



"Pressure and corrosion have likely damaged the wreckage, especially as it has been down there for so long. Flight recorders are not designed to withstand pressures of the depths that this aircraft actually went to."

But he warned that flight recorders recovered from other crash sites have not worked when they should have, with the reverse also true.



Do we know why Flight 447 crashed?



No cause has been determined. Studies of the debris and bodies that were found soon after the crash led the BEA to conclude the plane hit the water belly first, essentially intact. Oxygen masks were not deployed, indicating that the cabin did not depressurize, the BEA said in a 2009 report.



Tests have already brought into question the performance of pitot tubes, which measure the pressure exerted on the plane as it flies through the air, and are part of a system used to determine air speed.



Before it crashed, Flight 447 sent out 24 automated error messages that suggested the plane may have been flying too fast or too slow through the thunderstorms, officials have said.



The European Aviation Safety Agency issued a directive in late August requiring airlines to replace pitot tubes manufactured by Thales Avionics on Airbus A330s and A340s. It said airlines should replace them with other Thales tubes and those manufactured by Goodrich.



The lack of speed, wind or direction information also prevented the Autopilot system from functioning, said air accident investigator Alain Bouillard said at the time of the crash. "This tells us that the plane has to be, in this case, directed by the pilot," he said.



Flight recorders are not designed to withstand pressures of the depths that this aircraft actually went to.

--David Learmount, aviation expert



However investigators have subsequently cautioned that these factors alone would not have been enough to cause the disaster.

What about the weather?



Flight 447 was passing through an area prone to volatile and dangerous weather known as the Inter-tropical Convergence Zone (ITCZ), when it went down. The ITCZ is a belt of low pressure that wraps around the planet. Clouds and storms form along it because it is literally where the winds of the world's hemispheres meet.



Here, air and water temperatures are typically in the mid-80s. The warm, moist air is heated further by the blazing tropical sun. Steamy air, coming off the ocean, rises until it hits cooler, drier air aloft, forming clouds and thunderstorms.



These gigantic storms contain volatile updrafts and downdrafts that can move at speeds of 100 mph. The height of these storms also can tower to more than 10 miles in the air. Even if you stacked two dozen of the world's tallest skyscrapers on top of each other, they still wouldn't reach the tops of the biggest thunderstorms of the ITCZ.



However Learmount pointed out that hundreds of airliners pass through the ITCZ every day without incident. "There was another Air France flight 30 minutes behind Flight 447 that night and it encountered no problems," he said.

Any other theories?



According to Learmount, many aviation experts have yet to rule out the human factor. "The crash happened at around 2 am on a dark night when the error messages suddenly appeared and the autopilot tripped out." He said the crew, possibly at their deepest circadian low at this point, suddenly have this problem and they "fixate" on it.



"This is a syndrome," he said. "There have been lots of accidents where pilots have fixated on correcting a relatively minor problem and lose sight of the macro problem. Now we don't know that, but we do know the aircraft acted as if it was not being controlled purposefully.



"Whether it was out of control -- and I doubt this -- it was not being controlled. Imagine it is 2 am and two sleepy pilots encounter a problem. They don't have much to do so they decide to troubleshoot this problem. They fixate on it and forget the autopilot has tripped.



"The airplane meanwhile goes into a lazy spiral descent -- the pilots don't notice as it is all very gentle. And when they look up they don't believe what their instruments tell them and they get disorientated and can't recover."

He highlighted a similar case in 2004 when pilot disorientation and loss of control caused a Flash Airlines Boeing 737-300 to crash in the Red Sea shortly after take off from the Egyptian resort of Sharm el Sheikh. Though Egyptian authorities disputed the claim, aviation safety officials in France and the U.S. cited "spatial disorientation" as the likely cause based on evidence available, according to the U.S. National Transportation Safety Board (NTSB).

[Ancien]

Ca m'aurait étonné que tu ne déniches pas un article enfonçant les pilotes de ce vol !
Ce texte est magnifique , sublime , on dirait du Patrick Ester !
I have a dream : que même si les enregistreurs ne parlent pas , on puisse avec les morceaux récupérés ( et beaucoup de patience comme dans le cas de l'explosion du central d'un 747 ) trouver enfin les vraies raisons de ce drame .
Les pitots ? les pilotes ? les cunimbs ? l'altitude ? le sommeil ? la désorientation spaciale ? le radar ?......?

[Francis Bergeade]

Une question en forme de digression : Durée de vie du BEA ?

[Bugs]

Eh Ancien, Patrick Hesters, à côté de ce journaliste ce journaliste est un vrai scientifique!!!!... c'est tout dire!!!!

According to Learmount, many aviation experts have yet to rule out the human factor. "The crash happened at around 2 am on a dark night when the error messages suddenly appeared and the autopilot tripped out." He said the crew, possibly at their deepest circadian low at this point, suddenly have this problem and they "fixate" on it.

C'était couru d'avance....

[Laurent ALLIATA]

Pour Ancien . Excuse moi je ne fait que relater, je n incrimine nullement l équipage. Simplement vos avis , sur cette publication.

[Luc Lion]

La réponse ?
D'un point de vue certification, il faut se référer aux TSO C123a et C124a qui eux-mêmes renvoient vers les normes EUROCAE (d'après ce qu'on peut lire) qui ne sont pas accessibles. J'ai trouvé cette présentation d'Honeywell qui reprend le 'cahier des charges' : http://www.ntsb.gov/Events/symp_vr_topt ... ofield.pdf
D'un point de vue pratique - l'avenir nous le dira.

La norme EUROCAE ED-55 date de mai 1990.
Elle a été remplacée par la norme ED-56A en décembre 1993, puis ED-112 en mars 2003.
Une copie de la norme ED-112 peut être lue ici : http://www.china-cam.cn/chs/edit/Upload ... 224375.pdf

Les spécifications sur la durée minimale de rétention de l'information sont à la page 35 et celle sur la résistance à l'immersion sont à la page 46.

2-1.15 RETENTION OF RECORDED INFORMATION
Following the removal of electrical power to the recorder, the recording medium shall
be capable of retaining the information recorded during the preceding operating time
for a period of at least 2 years.

2-4.2.6 Deep Sea Pressure and Sea Water Immersion
a. Unless it can be shown that the recording medium can withstand the conditions
associated with deep sea immersion and that it is unlikely to be damaged as a
consequence of collapse of any protective armour, immerse the recorder in sea
water at a pressure of 60 MPa (equivalent to a depth of 6 000 m (20 000 feet)
for a period of 30 days. This period may be reduced to 24 hours provided that
the methods and materials used to protect the recording medium have been
shown to be unaffected by sea water. To avoid damage to the test equipment,
this test may be performed using any suitable liquid in the pressure chamber
itself together with a means to separate this liquid from the sea water in which
the recorder is immersed.
b. Unless it can be shown that the recording medium and the identification
required by paragraph 2-1.16.3 are resistant to the corrosive effects of sea
water, immerse the recorder in sea water at a depth of 3 m and nominal
temperature of +25°C for a period of 30 days. It is permissible to perform this
corrosion resistance test on a separate recorder independently of the main
sequence of tests except where sea water has been forced into the crash
protected module during the deep sea pressure test. The weight of the recorder
may be used as an indicator of this condition.
2-4.2.7 Fluid Immersion
This test is intended to show that the recording medium, in a standalone, environment
will not be damaged by immersion in fluids that maybe encountered. It is not intend to
show that cracked or damaged recording medium will not be damaged further by the
fluids. This test may be run as the last test in the suite of tests described in paragraph
2-1.16.2 or as a separate independent test.
NOTE: Typically the recording medium in a solid state recorder is memory chips
contained in the crash protected memory module.

Je n'ai pas trouvé de copie des normes ED-55 et ED-56A.

Luc

[020OVC]

J'ai trouvé chez Honeywell les descriptions d'un SSFDR
Il est en effet donné pour 30 jours à -20000ft

[FLYER34]

De plus je reste persuadé que l appareil n,a jamais impacté la surface intact .

Les débris semblent pourtant bien groupés pour un zinc qui, selon toi, se serait désintégré en vol (dernière image) :

http://www.bea.aero/en/enquetes/flight. ... u.site.php

[DC8]

Je ne suis pas enqueteur ni expert en alu, mais l' avant derniere photo, la ligne de hublots en bas a gauche, pour etre dechire comme cela . il a du falloir un sacre impact , et pas forcement a plat comme dit precedemment.
Ce que je trouve plus interessant c'est l' endroit.
De mon temps quand on recherchait un avion crashe , on commencait par sa derniere position connue et on avancait de la en spirale.
Les bonness recettes sont donc toujours valables..

[Laurent ALLIATA]

Je n ai pas dit que la totalité de l appareil s était désintégré , mais une partie . comment explique tu l absence totale de kéro a la surface lors des premières recherche?