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AF447

Old 12th Jun 2009, 22:11
  #1301 (permalink)  
 
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Application of rudder, instinctual -

what has been said of rudder input in normal flight is very interesting and telling. One should consider the animations the NTSB often publish as part of their public dockets. It would seem that a sudden upset almost always leads to rapid, one would say instinctual, rudder input from the PF. Sometimes this may be justified but from what has been said by pilots here, not often. Perhaps this goes back to training days in small aircraft where more rudder authority is required to escape an upset or establish stable flight in turbulence - the ideas imprinted there could somehow just become part of the airman's natural skills.

This aircraft had already accumulated 18000 hours in 4 years - that's a lot of flying. There are many unknowns about how fatigue accumulates in composite structures. We know in one case that the VS mounting lugs failed laterally, all at once, across many layers of composite material, in AA587. This must have taken the structural engineers somewhat by surprise. These things have not been around long enough to know all their properties under heavy use. One thing is sure, they don't respond well to rapidly changing stress like aluminum does, and they tend to fail collectively and not along easily identifiable cracks. One can point out here the failure of the carbon-carbon reinforced leading edge panels in the Columbia orbiter. The collected engineers gasped in amazement as a piece of foam smashed a 50cm hole in that panel - I don't think anyone expected this collective failure mode where a crack develops and propagates at such speed. One thing that may be important to consider is that these structures come out of fabrication with a lot of frozen-in stress that gets released almost explosively on failure.

-drl
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Old 12th Jun 2009, 22:44
  #1302 (permalink)  
 
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Towhee
Pretty good post for a newbie.

Succinct and logical without speculation
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Old 12th Jun 2009, 22:55
  #1303 (permalink)  
 
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My strong assumption

Yes mine was certainly a very strong assumption based on established facts regarding the weather, documented also on this forum. The pilot of AF 447 also radio-communicated the turbulence shortly before the series of faults kicked in.
All Weather radars were showing serious weather indeed, I am not talking about the radar on board this specific a/c, nobody knows if that was fully working in fact, but I am referring to the numerous public weather radars fully available on the web for that area at that time. Plenty of screenshots available online. Definitely serious weather but absolutely average and forecasted for the area and they were flying through it or very close to it, this alone would have never brought the plane down. We all know this.
I have never said that the weather caused this accident, what I have "rumoured" in my previous post instead is that established bad weather (fact) associated to the "apparently confirmed" pitot problem (nearly a fact) is a recipe for disaster, in my opinion, due to coffin corner and total lack of air speed data.
I do not think anybody can deny this.
Can anybody fly through coffin corner without airspeed data and survive?
As I said I also believe that ground speed data lost signal from satellite due to weather which normally is not an issue at all.
Again, a combination of factors but AF did not change pitot on this A/C as per AirBus notice. Coincidence or possible cause?
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Old 12th Jun 2009, 23:08
  #1304 (permalink)  
 
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The pilot of AF 447 also radio-communicated the turbulence shortly before the series of faults kicked in.
No factual information exists about this claimed communication (in public). It might be just a myth.
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Old 12th Jun 2009, 23:16
  #1305 (permalink)  
 
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We know in one case that the VS mounting lugs failed laterally, all at once, across many layers of composite material, in AA587. This must have taken the structural engineers somewhat by surprise.
Not so.

From the Airbus FCOM Bulletin 815/1

The Rudder should not be used:

- To induce roll
- To counter roll induced by any type of turbulance

Whatever the airborne flight conditions may be, full or nearly full opposite rudder pedal inputs must not be applied. Such inputs can lead to loads higher than the limit, and can result in structural damage or failure

The rudder travel limiter system is not designed to prevent structural damage or failure in the event of such rudder system inputs
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Old 12th Jun 2009, 23:26
  #1306 (permalink)  
 
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Can anybody fly through coffin corner without airspeed data and survive?
This term seems to be acquiring a life of its own... Coffin Corner. Goodness knows what any lay members of the public would think reading 'that' statement.

1) You don't fly 'through' that region, as if it's a part of the sky, you fly 'within' an altitide speed band, a regime, tight or wide in extent, as explained 100's of posts ago, probably +/- 25 kts plus other 'certificated' margins on top of that.

2) We don't know for sure that ALL airspeed and attitude data was lost, do we?

3) It's the turbulence that would be the primary difficulty, rather than being within a restrictive flight regime per se, if all airspeed data was lost, since a default attitude and power setting is the recommended 'exit strategy'

I agree a very serious situation would exist when losing airpseed data when 'way up there', and would be amplified by manifold issues at night in turbulence/ice/preciptation/lightning...

But saying flying 'through coffin corner' without airspeed data gives totally the wrong impression...
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Old 12th Jun 2009, 23:31
  #1307 (permalink)  
 
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My reply

I am quite sure I read it somewhere on an official source, I could be wrong of course but I think it is irrelevant because the fact that significant weather was in the proximity of this A/C I still see it as a clear FACT.
I think it is also a proven FACT that pitots had not been changed by AF on this specific machine.
Anything else is rumours and speculation of course but the two FACTS above "could" have been the initial trigger of a full loss of control with all consequences associated to this.
If the pitot issue will be confirmed as main trigger nobody can blame the two or 3 professional pilots in the cockpit.
I say this because I am also sure they knew very well about this pitot problem and they were all well trained on how to react to loss of airspeed data at altitude and in turbulence, but again real weather could have made it impossible. Sims, unfortunately, cannot fully replicate reality.
Reminder: it is not always easy to avoid those massive CB, sometimes you have no choice and go back, sometimes something strong, thick and black just comes out of nowhere, plus nobody knows if their wx radar was working and telling the truth.
Only this.
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Old 12th Jun 2009, 23:34
  #1308 (permalink)  
 
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Originally Posted by ILS27L
Definitely serious weather but absolutely average and forecasted for the area and they were flying through it or very close to it, this alone would have never brought the plane down. We all know this.
We don't, flying through very serious weather can bring aircraft down if control is lost - fact - which is why a/c have weather radar and pilots everywhere avoid the worst, even with fully operational air data displays - because you just don't know what is inside! Nature is not just incredibly powerful, but incredibly unpredicatble...
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Old 12th Jun 2009, 23:40
  #1309 (permalink)  
 
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Harry, unfortunetly coffin corner could be a very signicient part of this accident if the data is retrieved to show that the aircraft flew through an area of ISA+45 due convective lifting from the CB's in this ITCZ area. An A330 with 1.3G protection flying at max alt then going through this warm patch....well red bars will be meeting red bars on the speed tape.....
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Old 12th Jun 2009, 23:44
  #1310 (permalink)  
 
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i guess this thread did not leave out any form of possible reason of the accident ,,maybe the only missing link would be the lockness

Regards to the Crew i think the majority of pilots would face the same destiny as the AF 447 guys did,, thinking of collected experience

it is very sad when speculations start depending on clothes on or not, especially for the relatives to the victims ,, get that box recover now!!
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Old 12th Jun 2009, 23:45
  #1311 (permalink)  
 
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Thanks Bearcat, well aware...

I just think the post was adding little to what has been said ad infinitum so far, and sounded 'alarmist' in it's use of phraseology..

Flying 'through coffin corner without airspeed data'...
The a/c was probably flying up in that region and then lost airspeed data (probably)...

A very different emphasis, no ?

PS. We also don't know it was at max alt for its weight at the point
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Old 12th Jun 2009, 23:53
  #1312 (permalink)  
 
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ILS27L et al.

All this talk of wx avoidance and turning back etc. is all very 'armchair'.

Having flown through that region on many nights, sometimes you have to thread your way through the best (but no means nice) way possible using radar and eyes to guide you.

Turning around wasn't an option for me for 2 reasons: 1) past LPD to an island destination and 2) you'd be flying back through precisely the weather you were trying to avoid in the first place!!

Not been on AF447, I can't comment too much on their options, however stooging through the ITCZ isn't enjoyable, less so if you're facing failures many hours from a safe haven. Turning around may not have been an option.

I suggest we all await the official reports before spouting any more waffle.
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Old 13th Jun 2009, 00:04
  #1313 (permalink)  
 
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Grrr,

I can not for 1 second understand WHY in 2009 a so critical item as a black box should be aloud to follow a A/C down to the bottom of the sea

Thats totally insane,atleast they could put it in the v/s!! that one seams to exit and float most of the times
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Old 13th Jun 2009, 00:26
  #1314 (permalink)  
 
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Oxygen masks

Oxygen masks have been found from AF 447
No comment......
Peças e objetos do voo AF 447 - Álbum de Fotos - UOL Notícias
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Old 13th Jun 2009, 00:31
  #1315 (permalink)  
 
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More Pix.

This was published today. As it was taken at a photo session arranged by Brasilian authorities at Recife, one might assume more specific photos of the items will soon show up online.

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Old 13th Jun 2009, 00:34
  #1316 (permalink)  
 
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Debris Photos

They're all aat: FORÇA AÉREA BRASILEIRA - Asas de um povo soberano
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Old 13th Jun 2009, 00:36
  #1317 (permalink)  
 
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Autopsy results

Although this has been on the news here in Brazil for hours, I have not yet seen it mentioned here, I sent a post but did not get published here
basically most of the bodies had severe head injuries, none died from drowning..
No trace of fire or explosion was found on any bodies.
they were found in two separate areas, suggesting, only possibly, breakup in flight
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Old 13th Jun 2009, 00:37
  #1318 (permalink)  
 
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News from brazilian TV newsprogram

Hello all, I´ve followed and read all postings from 1st (closed) to this topic, many interesting things I´ve read since then.

Just 30 minutes ago, in the daily night-news-program on the brazilian TV channel "Band", the leader of the IML in Recife said (Institute for autopsies):
"The 16 bodies we´ve pre-autopsied, so far, can´t be recognized and or identified by parents/related persons. No one of the recovered bodies had clothes on. No one of the bodies had water in their lungs nor signs of smoke. No one of the bodies apresented any kind of fire/heat exposure. Allmost all bodies show middle to heavy internal contusions."

The conclusion from the news-reporter was for then, as he said:
"The theory comes near that the AF 447 suffered a quick decompression while in almost cruising altitude with or without total desintegration of the a/c and that the passengers and crew may have died before the impact on the ocean."

Sorry if my portuguese > english translation isn´t 100%, at least I din´t used some auto-translators...btw. I´m german.

Actual images of found debris you´ll find here: gallery on brazilian news-site: G1 > Mundo - NOTÍCIAS - Air France voo 447: galeria de fotos

Last edited by J.S.; 13th Jun 2009 at 01:27. Reason: Edited title + images link added
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Old 13th Jun 2009, 01:22
  #1319 (permalink)  
 
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No one of the recovered bodies had clothes on.
A very large percentage of accident victims in the Alps who slip/fall/tumble down mountains and experience a strong impact falling or multiple tumbling falls are stripped of their clothing. I'd like to point that climbers in the Alps dont(cant!) suffer Rapid Decompression yet often end up without clothing when falling down the hill.
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Old 13th Jun 2009, 01:23
  #1320 (permalink)  
 
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Hold contents

Just to throw another thought in here.
I wonder what was in the hold apart from containerised baggage..i.e. any large bulk cargo items that may or may not have been tied down and, might in the turbulence attain enough momentum to punch a hole in the skin.
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