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AF447 Thread No. 3

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AF447 Thread No. 3

Old 28th May 2011, 07:39
  #281 (permalink)  
 
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Cool

Hi,

Quote:
Make the math ... and the result is not "little less than one minute"
jcjeant... no the math is ok. 2 h 10 min 51- 2 h 10 min 16 is less than a minute.

THEN they lost proper indications a second time... Now whether the crew noticed they were valid for some time in the middle we'll never known. I personally doubt they noticed from the sounds of it.
My understanding of the BEA note is they are not accurate ....
When you make the sum of speed invalid time it's more than "less than one minute"
It's two losses of speed indication
Was better to put also a foot note for the second loss of valid speed.
It's important for the case.
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Old 28th May 2011, 07:49
  #282 (permalink)  
 
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No because the notes where in chronological order. They put that note after the first loss of indication. Which is where it belonged.

BTW can you tell me where you got this quote you posted?

Specific training for upset is not necessary on Airbus Fly-By-Wire protected aircraft
Pierre Baud
Vice Président Airbus Industrie (1998)
I ask because google has never heard of that quote.... and gogole knows everything.
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Old 28th May 2011, 07:52
  #283 (permalink)  
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I stand by post#1 here, posted nearly two years ago, and would repeat another post somewhere else that an easily accessible big button on this type of system is needed to enable direct control (assuming, of course, we have pilots in the cockpit and not computer operators).

There is still, even after all these years and accidents, much yet to be discovered on this FBW system and its failure/reversionary modes which appear to be built on the assumption that 'nothing can really go wrong so we don't need to worry too much about it.' Murphy's law applies.
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Old 28th May 2011, 07:54
  #284 (permalink)  
 
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beinville
you say I should google it?
jesus is that where you get your knowledge from?

Fact from personal experience .

All of my stall warnings in airliners have occurred in approach configuration low down in turbulence except for one in a high level holding pattern which was a mach stall.

Besides the obvious factors the margin over the stall is at it's minimum.

Once in initial climb at MTOW we hit minus 20+knots windshear with T/O thrust - procedure was full thrust and +5 pitch or thereabouts.
Speed was below V2.
Skipper followed procedure but speed decreased - he ignored my calls so I got on the stick and gently pushed it to drop the nose a couple of degrees and we started accelerating.(lower drag).

You have to realize that today everyone is taught to follow SOP but they do not always work.
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Old 28th May 2011, 08:03
  #285 (permalink)  
 
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Originally Posted by kilomikedelta View Post
Checkboard; Would the cockpit displays tell the pilot that the THS was at maximum nose-up so that stick aft wasn't helping?
The pilots did NOT fight the trim.
Please read the Report!
They produced/aggravated the trim.
Had they pushed the stick forward the NU trim would have been reduced by the Auto- trim.
There is NO indication of a runaway trim. It seems it was a commanded trim.
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Old 28th May 2011, 08:05
  #286 (permalink)  
 
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No I'm asking you why you say I am wrong?

The plane stalled at ~37,000 feet. There was absolutely no reason the pilot had to 'grab sky". Quite the contrary he was too high and (most surly) would not have stalled at 15,000 feet.

Now if you can tell me how I'm wrong, I'm all ears.

AND BTW your training or the lack thereof has nothing to do with this flight.
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Old 28th May 2011, 08:07
  #287 (permalink)  
 
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As I read BEA I was puzzled by THS being in almost full up position for about 3,5 minutes and not changing its position although PF made pitch-down input. Unfortunately report doesn't mention for how long pitch-down input lasted. I took my copy of A330 FCOM (not current one) and found out, please correct if I am wrong, that flight control law could have changed from ALT 2 to Abnormal attitude as angle of attack was greater than 30 deg causing no auto trim available until angle of attack decreases below 30 deg, which according to BEA report did not happen.



Is there any indication in the cockpit when this happens?
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Old 28th May 2011, 08:08
  #288 (permalink)  
 
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A qualified A330 type rating instructor talks about what he sees in the initial BEA information. The call asks some uncomfortable questions. The system of airline training needs to take another look but also there is work for Airbus pertaining to pitot tubes. It would seem there was a systemic failure on many levels.
PodOmatic | Best Free Podcasts
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Old 28th May 2011, 08:10
  #289 (permalink)  
 
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Stall recovery and auto flight

All

We have a loss of airspeed data because of ice in the pito that lasted for under a minute.

This triggered Alternate Law

After this the pitos came back, with the aircraft in a deep stall

Some questions :

1. Could the auto flight system be re-engaged in the stall ?

2. If so , would Alpha floor pulled them out of the stall ?


Simon
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Old 28th May 2011, 08:18
  #290 (permalink)  
 
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BEA Report – The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.

The last recorded values were a pitch attitude of 16.2 degrees nose-up, a roll angle of 5.3 degrees left and a vertical speed of -10,912 ft/min.


Where is the BEA quoted (THS) trim nose-up angle measured?

Is it an internal computed value displayed on EICAS?

Is it 13.2º on the cockpit pedestal trim wheels?

Is it 13.2º as shown on some aircraft where the horizontal stabiliser (tailplane) leading edge fairing meets the vertical fin?

Or ..... ?
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Old 28th May 2011, 08:21
  #291 (permalink)  
 
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Originally Posted by Bienville View Post

Really, if you have nothing to offer but drama laced nonsense, spare wasting the time of people who actually know a bit about how those airplane thingies fly.
It seems the problem is even the best pilots don't totally understand everything about their aircraft! It seems you need to do an IT course not a flight training course for this plane! Then you have the problem of airbus themselves claiming it couldnt stall!How many incidents have occurrd with the computer workIng against the pilots!

Frankly it's like a horror si-Fi movie of robots that try take over the world, the machine thinks it's better then the pilots, and the makers don't understand the complicated rare events, the events that kill.
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Old 28th May 2011, 08:22
  #292 (permalink)  
 
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Cool

Hi,

BTW can you tell me where you got this quote you posted?
Seem's Google is no more reliable .. lol
http://henrimarnetcornus.20minutes-b...1718484589.pdf
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Old 28th May 2011, 08:34
  #293 (permalink)  
 
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How many incidents have occurrd with the computer workIng against the pilots!

Frankly it's like a horror si-Fi movie of robots that try take over the world, the machine thinks it's better then the pilots, and the makers don't understand the complicated rare events, the events that kill.
I'm not sure how this nonsense got started... the computer was not "working against the pilot"... The report today CLEARLY says that all engine controls and input controls were functioning perfectly.

The pilots were working against common sense. When a plane stalls you push the nose down, not up. End of discussion.
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Old 28th May 2011, 08:36
  #294 (permalink)  
 
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> Seem's Google is no more reliable .. lol

OK anything more reliable than some guy's blog who today posted a quote that nobody has ever seen before?
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Old 28th May 2011, 08:41
  #295 (permalink)  
 
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Originally Posted by Machinbird View Post
The PRIMS could not have liked that and were no doubt all 3 disabled by that point. Once the PF started making nose down inputs, the Prims were still disabled and thus the THS did not move from its 13 degree position.. The crew did not get the proper feedback from their nose down control inputs (the stall warning actually came back) and they never saw the trim position due to their past training.

The only way to have saved the day was to get the trim rolled down manually to get the plane flying again.

Hmmm, looking through all the ACARS and the information we have at the moment I surely must have overseen the part where it was stated that all PRIM's were deactivated. I have seen PRIM1 and SEC1 but nothing more.
Could you point me to the information indicating loss of all PRIM's ?
That would have led to Direct Law btw.
Also I'm missing the part where it was stated that the pilots were vigorously commanding Nose Down only to be overriden by the Trim ?
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Old 28th May 2011, 08:49
  #296 (permalink)  
 
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henra one thing I really learned tonight is that people just make stuff up.
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Old 28th May 2011, 08:58
  #297 (permalink)  
 
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Beinville
you have to step back and put your thinking hat on.

One of the most frightening and unique generated sounds in a cockpit is the death rattle.

Add the fear, fatigue, disorientation and hypoxia factors to a host of contradictory information then the brain prioritizes.

The crew were faced with false stall warnings, overspeed warnings, control law warning, turbulence, probable dutch roll and a stab that was moving to the aft limit for whatever b****y reason.

I very much doubt if anyone in the crew had ever flown manually at altitude.

The body tenses with stress and fear and primeval instinct is to wrap oneself up in the foetal position - which could have resulted in the PF inadvertently putting a nose up input on the stick while he was sorting out the roll and what was really happening.

They had very little time and whether or not they had any correct speed indications they did not have the time to diagnose what was right or wrong.

Remember the air india 747 which rolled on it's back with a faulty horizon after take off - one instrument failure only.

BA nearly lost a 747 - the LAX one- as the crew didn't understand the basics of the fuel system and that technology goes back to Noah.
They also had the whole night to play around with it and get it wrong.

The myriad of posts trying to fathom out the computer system shows that it is not understood by the average bloke.
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Old 28th May 2011, 09:03
  #298 (permalink)  
 
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From yesterday's note from the BEA ... apart from the stall warning ... indeed there seems to be no indication (from the CVR) that they realized they were into a stall? If there was, why would the BEA chose to leave it out of their note?
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Old 28th May 2011, 09:09
  #299 (permalink)  
 
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One of the most frightening and unique generated sounds in a cockpit is the death rattle.

Add the fear, fatigue, disorientation and hypoxia factors to a host of contradictory information then the brain prioritizes.

..........


The body tenses with stress and fear and primeval instinct is to wrap oneself up in the foetal position - which could have resulted in the PF inadvertently putting a nose up input on the stick while he was sorting out the roll and what was really happening.
That kind of analysis is the last thing I would expect to see in an accident report.

The crew deserves a more thorough analysis
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Old 28th May 2011, 09:11
  #300 (permalink)  
 
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I think Blind Pew needs to follow his own advice and step back...

The crew were faced with false stall warnings, overspeed warnings, control law warning, turbulence, probable dutch roll and a stab that was moving to the aft limit for whatever b****y reason.
Ten out of ten for drama, five out of ten for accuracy. False stall and overspeed warnings are to be expected wth unreliable IAS. Control law warning - no big deal, alternate law is benign. Turbulence? An assumption. Dutch roll? And assumption. Moving stab? Not an issue. It was functioning as designed and the crew would not likely even be aware of the stab position.

I very much doubt if anyone in the crew had ever flown manually at altitude.
I have flown an Airbus manually at altitude. It's exactly the same as flying it at 10,000 feet thanks to the flight control laws, either in Normal or Alternate law. It's not an issue.

The body tenses with stress and fear and primeval instinct is to wrap oneself up in the foetal position - which could have resulted in the PF inadvertently putting a nose up input on the stick while he was sorting out the roll and what was really happening.
Errrrr - you don't accidentally put full back stick on, and not for 30 secs. Your arm will get very tired.

They had very little time and whether or not they had any correct speed indications they did not have the time to diagnose what was right or wrong.
Thats why you have an unreliable airspeed recall item.

BA nearly lost a 747 - the LAX one- as the crew didn't understand the basics of the fuel system and that technology goes back to Noah.
They also had the whole night to play around with it and get it wrong.
There was never any chance of losing the aircraft, and the issue which manifested itself only became apparent at top of descent and would have resolved itself of it's own accord anyway. Lots of fuss about nothing.

The myriad of posts trying to fathom out the computer system shows that it is not understood by the average bloke.
Fortunately 'average blokes' aren't let loose on multi-million dollar airliners. They have to have a lot of training first, which is why many Airbus experienced pilots find this kind of speculation tedious.
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