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Graybeard : The flight you are referring to was operated as TW841. It was not NWA.
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SMOC
The forum post was on 1 June. The article referenced in it is dated 1/06/11. Here is the link from #1242: #1242 (permalink) JamesT73J Join Date: Oct 2003 Location: Hampshire, UK Posts: 159 According to flight global, automatic stab trim should have been inhibited when alpha > 30 degrees - Stalled AF447 did not switch to abnormal attitude law but it was not. Finally, here is the initial text copied from the FlightGlobal article: DATE:01/06/11 SOURCE:Air Transport Intelligence news Stalled AF447 did not switch to abnormal attitude law By David Kaminski-Morrow http://aka-cdn-ns.adtech.de/apps/404...2Id5/158271971 http://adserver.adtech.de/adserv%7C3...rp=[group] Investigation into the accident sequence of Air France flight AF447 has revealed that the Airbus A330 did not enter the abnormal attitude law after it stalled, despite it |
Thanks ExLeftSeat. As a politician would say, "I misremembered; I misspoke; it happened Northwest of New York" etc. I'll go back and fix it.
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bubbers44
...... why don't they release more information about what they know? Bet your bottom dollar lawyers and insurance assessors are keeping a close eye on it all and doubtless advising what should and what should not be released until they are ready for the full story - and with it the apportionment of blame - to be released. but then ... just as some burglars fall over and beat themselves up whilst resisting arrest, who knows exactly how much of the CVR was preserved whilst at the bottom of the Atlantic, and available when the boxes were opened ? but then I'm a cynic. |
Do you guys get to hand fly IMC at cruise flight levels or is it just too stall-prone? Just a curious question.
Ikeep wondering what I would have done. stall alarms leads to (immediate....thought never ever ever ignore this..) -same power ( ie minimum change in known cruise settings as your speed indicator has just dropped out) -a little immediate gentle nose down alteration in elevator pitch ( you would have memorised the pitch attitude and AoA in cruise before bed every night in preparation for this precise moment...)..anything to make the stall warning go quiet and get some airover the wings -wings level - and an immediate check of the autotrim setting (as it seems thats the Airbus elephant in the room if theres no elevator authority and you're nose high +++ and descending at 10,000 fpm!) sound like good initial steps to me, and .. -fly it first and foremost on meticulous instrument scan, and worry about all the alarms and noise later ( stall warning excepted of course) -gradual turn away from track and storm if one has to -dont worry about altitude loss as its the best friend you have - in fact lose 10 000 feet very gradually and you'll feel even better about the stall risk im sure I only fly a Duchess. |
Do you guys get to hand fly IMC at cruise flight levels |
or is it just too stall-prone? |
Thank you for the Information - then it must have made the sudden alteration in the situation seem all the more challenging for the poor pilots - having to hand fly in circumstances not previously familiarised , with no speed indication , in IMC/Storm conditions.
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According to flight global, automatic stab trim should have been inhibited when alpha > 30 degrees |
Originally Posted by learner001
Tip of the iceberg...?
From pointers to drums... From dynamics to numbers... Tiny observations large outcome... When I started flying ‘digital’ I missed and preferred the ‘old’ familiar dynamic moving pointers on the Airspeed indicators and Altimeters, rather than the relatively ‘dumb’ moving number-tapes and/or drums on the flight displays. And my ‘emotion’ is not limited to Airspeed indicators and Altimeters only. Of course, as with all sort of changes, I was told that I “just have to get used to it!” OK... Fair enough... But, although I am getting more and more used to ‘flying digital’ by now, on occasion, I really sense the lack of instant dynamic ‘speed and altitude situational awareness’ that the ‘old’ analogue Airspeed indicators and Altimeters with their moving pointers will give us more or less instantly. Looking at the tapes I have to figure out: Are the changes going up or down? Moving Fast or slow? Is it an increase or a decrease? What’s the trend? Things, that I would instantly be aware of with the analogue indicators. With digital indicators, however, I need more of my brain capacity to ‘translate’ the sheer changing of numbers on the rolling tapes (or drums) into dynamics. Oh, yes... We’ve got the ‘speed trend arrow’ to sort the speed thing out... Haven’t we... But, then again, isn’t this turning the things upside down? In every new aeroplane that our company receives, even the ‘last resort’ analogue standby instruments have been replaced by a single digital display. Man tries a lot of things to improve safety. On the other hand, in my opinion, these efforts are broken down again, unnoticed. As for hindsight typing behind the computer: Most of our daily flying ends at a couple of hundred feet going out and starts again at a couple of hundred feet coming in... Almost every flight we are being flown, mostly by the comfort of automation, very near to the ‘coffin corner’... The ‘gap’ being smaller one time than the other. I wonder how many of us really actively realise this... At high altitude in the very thin air, especially in turbulence at night, a cockpit can turn into a relative ‘hell’ very abruptly if the Autopilot kicks off... (LOL most probably from many in here...) Controls will be very sloppy in conventional aircraft. In FBW aircraft this will be even more (un) noticeable, as there is different or no direct feedback. In both cases, while you’re shaking, you need to handle the controls like being a Swiss watch maker. And you are now manually manoeuvring within this tiny confined little gap... If you’re lucky you may have done it may be a couple of times. Even ‘minutes’ would do a great deal of benefit already... But it is something we hardly actually ever do...! Are we stupid, then? We train constantly for all sorts of situations... Or could here be a training deficiency? If you have/were never trained in hand flying close to the ‘edges’ of an envelope (or even outside an envelope), or if you have never actually been hand flying close to the ‘outside’ of an envelope, chances are that you won’t even notice that you’re going out... Whilst thinking you’re ‘hanging in there’... And so far, so good... How much ‘flight time’ were our unfortunate colleagues granted to log in their logbooks on actual hand flying the plane in that tiny little gap, before they all of a sudden were forced and committed to do so in a very, very narrow gap. Whilst probably shaking, vibrating and being bombarded with all sorts of alarms going off... So, whilst trying to analyse, I have learnt to always remain respectful and very humble and do a great deal of effort to see the whole picture... 29th May 2011 at 21:03. Well said Sir, well said! |
i'm not a pilot, know nothing about flying.
i'm curious to know if a large commercial airline has ever been successfully recovered from a deep stall such as occured in this case ? either in test flights, real life or even on a sim ? is it actually possible and if so what altitude would be required? i assume would require a change from tail down via wing down to nose down attitude, and that would be very tricky and unstable, risking spinning or going upside down and using up lots of altitude ?! |
i'm curious to know if a large commercial airline has ever been successfully recovered from a deep stall such as occured in this case ? The answer comes out that the denominator needs to approach zero. |
That would give you a number approaching infinity. Computers do very strange things with denominators that approach zero - like crash.
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Okay, how about the result is unity. 1/1. Every Stall gets a recovery.
Picky kmd. ;) |
Bearfoil; AF447 didn't recover. My point was that floating point operations in computers with a finite operand length when encountering a divide by zero may do peculiar things and that the interrupt to handle that exception has to be VERY well defined. Cheers.
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I assume would require a change from tail down via wing down to nose down attitude, and that would be very tricky and unstable, risking spinning or going upside down and using up lots of altitude ?! Best read the few thousand previous posts on all AF447 threads to catch up a bit first, then maybe post. |
I'm studying post graduate aviation medicine at present
There is a physiologic reason why pilots prefer analogue to digital readouts, and why smaller moving number images attract less attention than dials moving. The occipital cortex ( via magnocentral pathways via lateral geniculate nuclei)is hard wired to interpret visually perceived movement as potential danger without reference to "higher centres" interpeteting the visual data. ie if you saw an analogue altimeter unwinding the brain links to potential danger are more immediate, and the same would apply to the VSI in typical analogue form. When its moving tapes of numbers occuppying less visiual space and requiring more intellectual input to interpret , its natural to feel less concerned, and in fact the brain is hard wired to feel less concerned. All of this adds to increased risk at the edge of the flight envelope... |
You are right. The occipital cortex is more sensitive to peripheral field movement (millenia of evolution) compared to changes within the macular areas of the cortex. Engineers and flight deck crew are not taught that which may be why they gravitate toward digital displays until their occipital cortex clashes with their cerebellum. Whence spatial disorientation.
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Mimpe gets an attaboy:ok:
I'm studying post graduate aviation medicine at present There is a physiologic reason why pilots prefer analogue to digital readouts, and why smaller moving number images attract less attention than dials moving. The occipital cortex ( via magnocentral pathways via lateral geniculate nuclei)is hard wired to interpret visually perceived movement as potential danger without reference to "higher centres" interpeteting the visual data. ie if you saw an analogue altimeter unwinding the brain links to potential danger are more immediate, and the same would apply to the VSI in typical analogue form. When its moving tapes of numbers occuppying less visiual space and requiring more intellectual input to interpret , its natural to feel less concerned, and in fact the brain is hard wired to feel less concerned. All of this adds to increased risk at the edge of the flight envelope... I may be one of those 'dinosaur pilots', but by gosh, I know truth when I see it. Even a moving needle on a digital display doesn't get the mental recognition and attention that the real thing gets. |
The old gravity dependent turn and bank indicator and the magnetic compass rely on forces that are difficult to manipulate by publicists or lawyers. They give you pitch, attitude and yaw but not in 3D with Hollywood star endorsements and stock options so why would anyone even look at them?
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