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AF447 Thread No. 3

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AF447 Thread No. 3

Old 28th May 2011, 16:03
  #381 (permalink)  
 
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Hi spagiola,
Originally Posted by spagiola
EVERY single post on that site seems to be by the same, vitriolically anti-Airbus poster. Caveat emptor, I'd say.
Well... look at this url for this pic, the same posted by jcjeant: http://jacno.com/prov/images/extrait-fdr-cvr.png
jacno.com = Norbert Jacquet.
If one really knows who is this guy, the vitriolically anti-Airbus is obviously an understatement. It looks like he's got few fans around, including here (jcjeant,...), that are pursuing the very same crusade than him by always relaying all his "very informatives and unbiased" positions.
Call them trolls, whatever, but be sure that this won't stop any time soon.
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Old 28th May 2011, 16:05
  #382 (permalink)  
 
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missing vital clues

G'day all,

Very fascinating discussion going on here guys [and gals], well done.

At this stage we are obviously missing some vital clues but I would like to pose a couple of questions if I may:

1> Given the data released thus far can we be absolutely certain of complete system and airframe integrity up to impact?

2> Do we know without doubt there was no degradation of other instrumentation including altimeter & AI?

3> Are we in a position yet to completely rule out external factors including extremely volatile air masses?


Cheers
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Old 28th May 2011, 16:06
  #383 (permalink)  
 
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Also , could there be a link to this and the QF 330 incident
Not according to those in the know.
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Old 28th May 2011, 16:08
  #384 (permalink)  

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K.I.S.S.

Why can't it just be simple? All these technical issues are very interesting but are you drilling too deep? I'm not argueing for/against the AB philosophy (for which I am the No 1 supporter; I just love the 320/330), only trying to come to terms with what actually happened.


They lost the pitots and, therefore, airspeed tapes. They had not experienced this before (I have never had a go at this at high level in the sim or the A/c). The PF chose to accept he was overspeeding and pulled the nose up. The auto-trim responded and wound in the nose-up trim. That's what it does. PF is now three minutes from crashing and the captain (probably wisely) didn't exchange seats with either of them (who knows what the turb was at the time?).

Lots of NU trim, at night, no airspeed tapes and three minutes to go.

Would you have done better?

Having spent years watching crews in the sim sorting out problems and noting the time it has taken them, three and a half minutes is not a lot.
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Old 28th May 2011, 16:10
  #385 (permalink)  
 
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Come on guys, for all we know they DID check the GPS/inertial ground speed. The report just does not tell us anything of the sort, just as it does not tell us anything else other than some stuff that does not make any sense at all. So please don't say: why did they not do this or that. We just don't know yet.

Of course a lot of scenarios spring to mind, but none can be verified.
Take for example the 16,5 degree pitch up that someone suggested might be a windshear avoidance reaction. Well, maybe. But you would expect TOGA to be applied in such a situation, which did not happen untill much much later! So much for the windshear scenario.

Did the PF think he was overspeeding, hence the initial pull up? Maybe. But he did not close the thrust levers untill 3 minutes after this pitch up.

So no matter what scenario you (or I) come up with, it does not make ANY sense. We are not given crucial information.



Anyway, to me, just as puzzling is the weather these guys were in and it surprises me there is no more discussion about it. There must have been a lot of water floating around at FL350 to cause the pitots to block. I have never flow commercially in those regions so I can't talk from experience about this. So what I'm asking is, is it known to have icing at those altitudes without entering a CB? Is it common? Is it possible?

Last edited by PENKO; 28th May 2011 at 16:24.
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Old 28th May 2011, 16:18
  #386 (permalink)  
 
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Ashling
I believe they had sensory overload and made an incorrect assessment.

I concur whole heartedly with your post.

Unfortunately many will bury their heads in the sand and say it can't happen to me.

What many of you will not have done is to be locked into a decompression chamber and be starved of oxygen as was compulsory in my training. We had to sign a legal waver and had a doctor and medic in the tube with us. The exercises that we performed were to demonstrate our mental degradation at altitude leading to unconsciousness.
Not posing but just some training is more comprehensive than others.


I recently did a very well briefed SIV paragliding emergency course nr Annecy.
During a relatively extreme maneuver (high G) I put it the wrong input although I had 2 way com and was fortunate that I didn't have to throw my reserve.

In my younger days I was known as a bit of a hot shot - I now accept that I am an old man and make lots of mistakes.

Fortunately my last company look after me extremely well and although I still have a valid atpl I haven't needed to work for more than a decade.

I am just happy that I don't have to fly 12 hour night flights through the ITCZ anymore.
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Old 28th May 2011, 16:21
  #387 (permalink)  
 
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bienville...

You found this site and thread and leapt onto it like a young tiger -- a young tiger who hasn't yet learned most of life's lessons, including respect for other tigers. In one of your first posts you insulted a very respected and long-term ppruner who has more wisdom and experience in her little finger than you seem to have in your whole being.

Despite your screams of pilot error, there is nowhere near enough info (publicly) available yet to support any of your assertions. Your simplistic view of what went on up front on that horrid night shows you have little kowledge (or concern) about how the accident chain works in real life.

You yell at ppruners who have been here for years -- and discussing AF447 for years -- presuming to instruct them in how to behave and how to identify trolls.

Saddest thing, though you have been here less than 24 hours, you have succeeded in bringing the level of this thread down dramatically.

JT? You out there?....

Last edited by Jetdriver; 28th May 2011 at 20:42.
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Old 28th May 2011, 16:31
  #388 (permalink)  
 
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Saddest thing, though you have been here less than 24 hours, you have succeeded in bringing the level of this thread down as fast as the doomed aircraft itself.
Watch out you are being a bit melodramatic!
Well said!
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Old 28th May 2011, 16:32
  #389 (permalink)  
 
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Windsheer

Out of my league, but could the assumed loss of situational awareness been due to belief of a non-existing wind sheer pulling the plane first up and then down?

I mean, purely from psychological point of view, they just entered a weather front, then loose speed indication and for what ever reason the plane is first rapidly gaining altitude only to loose it soon after. Could this be part of the scenario, making the believed wrong calls a bit easier to comprehend?
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Old 28th May 2011, 16:35
  #390 (permalink)  
 
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cargo ? fuel trim ? both?

It went into the deep stall too easily. Should the cause rest only on the THS trim and/or the PF's pitch-up inputs ?

Sorry if I seem rather intuitive than technical...
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Old 28th May 2011, 16:38
  #391 (permalink)  
 
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Thanks, Grizzled

Well said.
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Old 28th May 2011, 16:40
  #392 (permalink)  
 
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Many posts discuss the continuous back stick, but nobody replied to my earlier thread re the sustained (30s) full deflection roll input.

I find this very significant - but puzzling - for a number of reasons:

1. I can only suppose that it was in response to an opposite bank, caused by turbulence => the PF was following the AI in roll; why not also in pitch?

2. 30s is an age to hold in a roll demand - an absolute age. If the aircraft wasn't responding (which one supposes it can't have been) then this would to most of us must again re-inforce the conclusion of stalled flight and certainly eliminate a high speed dive.

To me this can only point to extreme disorientation/sensory deception and refusal to believe the instruments. As has been noted before, a/c have been lost due to e.g. a single AH failure; the level of failure here was more serious, was in IMC at night...
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Old 28th May 2011, 16:44
  #393 (permalink)  
 
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More to it than just pilot control inputs

I am a pilot and a software engineer. Back in April I posted about a scenario that turns out to be quite similar to what the FDR and CVR describe. In that post I suggested that the pilots would have applied TOGA and full nose up trim. I think it is eminently reasonable, given the pilots' procedures training, practiced in the sim, and their confidence in the FBW system, that the pilots applied nose up control inputs and full power. Don't blame the pilots!

I believe the fundamental cause was that the computers flying the plane used invalid air data inputs (altitude and airspeed) with pilot control inputs that were based on the assumption that the computers had valid air data inputs (altitude and airspeed). I believe the FBW was not designed or tested against this particular set of inputs. That is based on my software engineering expertise and not so much what I know about flying.
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Old 28th May 2011, 16:48
  #394 (permalink)  
 
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Techgeek, what scenario would that be at FL350? No pilot knows of a scnenario where you would pull up violently (7000 feet per minute) at FL350. Mind you, without TOGA! That came much later, with the second stall.
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Old 28th May 2011, 16:58
  #395 (permalink)  
 
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I believe the fundamental cause was that the computers flying the plane used invalid air data inputs (altitude and airspeed) with pilot control inputs that were based on the assumption that the computers had valid air data inputs (altitude and airspeed). I believe the FBW was not designed or tested against this particular set of inputs. That is based on my software engineering expertise and not so much what I know about flying.
Nope. The AP and AT disconnected exactly as designed and the PF reported "I have the plane".... at this point the aircraft went where the human pointed it. It was pointed up (and left I believe, in response to a right roll). The computers at this point applied the design protections (where possible) based on Alt Law being in effect, but did NOT control the aircraft in any rational sense of the word - that was the bloke moving the joystick around. Unfortunately the human reaction does not seem logical to (most) pilots here and the aircraft ended up in a pretty bad attitude. (Nose high, AoA very out of shape, and minimal airspeed).

Why is this so hard to understand?
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Old 28th May 2011, 17:02
  #396 (permalink)  
bearfoil
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"...Many posts discuss the continuous back stick..."

Please show where in the BEA report this is stated.......

"Stick" is a misnomer, 'mainly'. The Sidestick has its own character, and inputs communicate with the computer, not the a/c. It is a discussion, not an assumption.

Philosophy and mechanicals are different words, and in their muddying, much distraction.....
 
Old 28th May 2011, 17:05
  #397 (permalink)  
 
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Originally Posted by grizzled
Saddest thing, though you have been here less than 24 hours, you have succeeded in bringing the level of this thread down dramatically.
It has been a team effort.
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Old 28th May 2011, 17:20
  #398 (permalink)  
 
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One Outsider

I grant you that
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Old 28th May 2011, 17:37
  #399 (permalink)  
 
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Richard Feynman - "The Meaning of it All"

Feynman, the Nobel Prize winning quantum mechanics guru, wrote about a number of subjects besides physics. He was asked why some students had such difficulty learning to spell certain words. Feynman said the problem wasn't the student, but that the word was not spelled correctly.
Maybe that applies here. If competent, highly trained professionals have difficulty sorting out an already confusing situation in a short period of time, maybe the system is the problem.
Designers need to rethink the interfaces with the pilots, including the complexity of the different levels of degradation. Software engineers need to have a bit less confidence in their ability to produce an infallible product. Time for a major rethink all around, IMHO.
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Old 28th May 2011, 17:43
  #400 (permalink)  
 
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Well my animus for software "engineering" is hereby exhibited - all the fancy laws and protection modes had the precise effect of sending 228 people to the bottom because they dealt with meaningless abstractions, not a real world problem.
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