AF 447 Thread No. 6
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Training
Link Trainers did not attempt to simulate any ONE kind of aircraft. It was used to train many thousands of pilots in what it COULD do, teach and then PRACTICE some aspects of flying on instruments.
At that time, there was nothing better.
The Stratocruiser simulator had a model landscape with a "small" television camera, which then moved in sympathy with the pilots inputs to give a visual image, initially for the Captain, probably in black and white !
The point that I was trying to make, was that PF, (any PF ?) might have made a better show, if he had had practice. I do not know how many hours a year Simulators are used, 3,000, 4,000 or 5,000 hours - or more ?
If some bean counter queries the cost, just say 447.
At that time, there was nothing better.
The Stratocruiser simulator had a model landscape with a "small" television camera, which then moved in sympathy with the pilots inputs to give a visual image, initially for the Captain, probably in black and white !
The point that I was trying to make, was that PF, (any PF ?) might have made a better show, if he had had practice. I do not know how many hours a year Simulators are used, 3,000, 4,000 or 5,000 hours - or more ?
If some bean counter queries the cost, just say 447.
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Quote:
Originally Posted by xcitation
Yes PF did take the extreme step of deploying the airbrake. Hence PF actions were consistent with him being convinced of overspeed at that point.
Agreed, but he doesn't seem convinced enough to press the point with the PNF when he chews him out for it and shuts down that avenue. The PNF's immediate following action is to defer to the Captain.
Originally Posted by xcitation
Yes PF did take the extreme step of deploying the airbrake. Hence PF actions were consistent with him being convinced of overspeed at that point.
Agreed, but he doesn't seem convinced enough to press the point with the PNF when he chews him out for it and shuts down that avenue. The PNF's immediate following action is to defer to the Captain.
Yes. I agree that PF was confused at best. What concerned me was that he could have hit his head as stated in the BEA report, which has never commented on in this forum (unless I missed it).
Someone did mention Laural and Hardy as far as communications. I am incredulous/perplexed by their sloppy communications in such a grave situation. It looks like they got into some very bad verbal habits and could not switch into professional comms mode when things went wrong.
PNF was not much better at his role. He should be pulling out the correct high altitude UAS checklist and making some direction to the PF. None of them ever mentioned the word stall / décrochage even if only to dismiss it as being false. What more important warning do you have on an aircraft when it tells you that it is now a falling lump of metal and no longer a flying machine. At least someone should happen to mention it amongst all the bickering and confusion. If the house is on fire do you ignore it and carry on fixing a leaky faucet/tap?
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Quote:
Originally Posted by xcitation
Yes PF did take the extreme step of deploying the airbrake. Hence PF actions were consistent with him being convinced of overspeed at that point.
Agreed, but he doesn't seem convinced enough to press the point with the PNF when he chews him out for it and shuts down that avenue. The PNF's immediate following action is to defer to the Captain.
Originally Posted by xcitation
Yes PF did take the extreme step of deploying the airbrake. Hence PF actions were consistent with him being convinced of overspeed at that point.
Agreed, but he doesn't seem convinced enough to press the point with the PNF when he chews him out for it and shuts down that avenue. The PNF's immediate following action is to defer to the Captain.
A negligible effect would strongly indicate low airspeed.
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Originally Posted by Clandestino
Because you say so? Because Airbus has radically redesigned rudder architecture on 330s since a couple of years ago? Because someone is unable to appreciate the difference between "controlled" and "operated" when discussing the flight controls as in "manually controlled and hydraulically operated"?
Let me see, if rudder control is electrical does it mean it can be mechanically-controlled too ?
JD-EE,
Your post (#636) about spammers and malware, though it will be considered OT by some, contains very helpful insights for those of us less knowledgeable in these things. Thanks!
Your post (#636) about spammers and malware, though it will be considered OT by some, contains very helpful insights for those of us less knowledgeable in these things. Thanks!
...lateral and directional might have had to be a bit of a fudge, but plenty of high AoA data exists even there.
High fidelity simulation of post stall 'beta' effects (in all configurations) is an area of concern that is currently being aggressively addressed...
(by people much smarter than me. Like yourself.
)
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Cognitive Overload of a Team
Dozy..
I think there is a mix of overload impacts that affect each crew member differently.
First there is what is called the 'classic inverted U curve (Yerkes and Dodson 1908) which balances arousal and performance. The crew were at the lowest point for attention and arousal at 2am in a relatively boring and benign cockpit environment. This is the worst level of attention and alertness the bottom of the inverted U and poor performance. Ideally, the crew need to be engaged so that their arousal/attention is at the top of the curve of the inverted U and performance is best. However, instead, what happened was a sudden burst of emergency activity both mentally and physically demanding with instruments and techniques routinely used in Normal Law not working. Learned sim ride behaviors seemed to make things worse. This moved the PF at least, right to the other end of the Inverted U where the level of arousal was so high that performance drops off. At that level the cognitive overload that we had discussed could lead to 'attentional tunneling' (or cognitive tunneling) where the PF concentrates on a few aspects of the task and is not conscious of anything outside those aspects.
The PNF has a similar jump to the wrong side of the U but as you state has a problem as he finds that what he says is not being listened to. This is probably due to the PF attentional tunneling, but PNF may think that it is some lack of authority on his part - the authority gradient. He may also be aware that he is overloaded with all the various aural verbal analysis, visual verbal analysis trying to read ECAM listen see what PF is doing now. So PNF wants the captain back. It is noticeable, that PNF is not making it plain shouting that the aircraft has stalled get the >deleted< nose down!! - no, PNF is muttering about the delay getting the captain.
When the captain does arrive, instead of a peaceful cockpit that he left, it is a cacophony of alerts and wind noise. PF is 'making mayonnaise' with the SS and presumably staring fixedly at the instruments. I did not see any transcript of a succinct briefing from PNF to the captain giving an order of events detailing the problems - only the captain being asked what did he think is going on? Was the captain even told that the aircraft was in Alternate Law? (is it immediately obvious if you are not told?) Would the captain have identified the stall if he had just a three sentence briefing on events?
I have said elsewhere that this turned into a human factors nightmare. Books will be written about this incident. Procedures and training both live and simulated will be changed I hope for the better.
I'm not sure if human/machine cognitive overload is the problem here so much as the level of pressure and stress on the PNF. For all my opinion's worth as a layman with an interest, could it be the human/human interface that is causing the issue?
First there is what is called the 'classic inverted U curve (Yerkes and Dodson 1908) which balances arousal and performance. The crew were at the lowest point for attention and arousal at 2am in a relatively boring and benign cockpit environment. This is the worst level of attention and alertness the bottom of the inverted U and poor performance. Ideally, the crew need to be engaged so that their arousal/attention is at the top of the curve of the inverted U and performance is best. However, instead, what happened was a sudden burst of emergency activity both mentally and physically demanding with instruments and techniques routinely used in Normal Law not working. Learned sim ride behaviors seemed to make things worse. This moved the PF at least, right to the other end of the Inverted U where the level of arousal was so high that performance drops off. At that level the cognitive overload that we had discussed could lead to 'attentional tunneling' (or cognitive tunneling) where the PF concentrates on a few aspects of the task and is not conscious of anything outside those aspects.
The PNF has a similar jump to the wrong side of the U but as you state has a problem as he finds that what he says is not being listened to. This is probably due to the PF attentional tunneling, but PNF may think that it is some lack of authority on his part - the authority gradient. He may also be aware that he is overloaded with all the various aural verbal analysis, visual verbal analysis trying to read ECAM listen see what PF is doing now. So PNF wants the captain back. It is noticeable, that PNF is not making it plain shouting that the aircraft has stalled get the >deleted< nose down!! - no, PNF is muttering about the delay getting the captain.
When the captain does arrive, instead of a peaceful cockpit that he left, it is a cacophony of alerts and wind noise. PF is 'making mayonnaise' with the SS and presumably staring fixedly at the instruments. I did not see any transcript of a succinct briefing from PNF to the captain giving an order of events detailing the problems - only the captain being asked what did he think is going on? Was the captain even told that the aircraft was in Alternate Law? (is it immediately obvious if you are not told?) Would the captain have identified the stall if he had just a three sentence briefing on events?
I have said elsewhere that this turned into a human factors nightmare. Books will be written about this incident. Procedures and training both live and simulated will be changed I hope for the better.
Not so sure the crew was just sitting back and enjoying the ride, Ian.
They had just told the flight attendants to be ready for some bumps, and they were turning a bit to left of course.
The human factors should play a large part of any recommendations, and the crew coordination/procedures should also be addressed.
They had just told the flight attendants to be ready for some bumps, and they were turning a bit to left of course.
The human factors should play a large part of any recommendations, and the crew coordination/procedures should also be addressed.
The point that I was trying to make, was that PF, (any PF ?) might have made a better show, if he had had practice. I do not know how many hours a year Simulators are used, 3,000, 4,000 or 5,000 hours - or more ?
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Cognitive Channel
Clandestino
Each of the cognitive channels in YOUR brain can only handle one input at a time. There are discussions about how many cognitive channels there are but if you really think you can concurrently read a text, while repeating a well known rhyme correctly, listening to someone talking and accurately writing down what they are saying - then you are NOT human.
I suggest that you google 'Wickens cognitive channel' and read the research there much of which was carried out with pilots. You will see how easy it is to initiate cognitive tunneling in professional pilots.
It is the poor designs and procedures that do not take account of human cognitive limitations that can lead to accidents.
Originally Posted by Ian W
(...) it is because the human brain has a limited number of cognitive channels and they can only handle ONE input at a time.
That's the best explanation of someone's inability to chew gum and simultaneously tie his laces I've heard in a long time. Attention distribution, proper scanning and avoiding the fixation are basic pilot's survival tools, taught and checked from day one at the controls. If you suck at them, tough luck, you can not be a pilot. What AF447 crew did was the sign of the severe incapacitation, not usual and ordinary human behaviour.
(...) it is because the human brain has a limited number of cognitive channels and they can only handle ONE input at a time.
That's the best explanation of someone's inability to chew gum and simultaneously tie his laces I've heard in a long time. Attention distribution, proper scanning and avoiding the fixation are basic pilot's survival tools, taught and checked from day one at the controls. If you suck at them, tough luck, you can not be a pilot. What AF447 crew did was the sign of the severe incapacitation, not usual and ordinary human behaviour.
I suggest that you google 'Wickens cognitive channel' and read the research there much of which was carried out with pilots. You will see how easy it is to initiate cognitive tunneling in professional pilots.
It is the poor designs and procedures that do not take account of human cognitive limitations that can lead to accidents.
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Ian W knows of what he speaks.
Any of you who think you can always multitask in a highly demanding environment have forgotten your early days of instrument training where it was easily possible to break down your scan.
We try to plan ahead to prevent overloads, but occasionally stuff can snowball.
There is no pilot alive who's scan cannot be broken by the right circumstances.
It is how you recover from this mess that separates the men from the boys.
Judging from how little actual stick time airline pilots seem to be getting, I am amazed that loss of control incidents are not more prevalent.
The term scan as I am using it refers to the multi-sensory process of acquiring information regarding your flight from all sources. It is very close in meaning to situational awareness.
Any of you who think you can always multitask in a highly demanding environment have forgotten your early days of instrument training where it was easily possible to break down your scan.
We try to plan ahead to prevent overloads, but occasionally stuff can snowball.
There is no pilot alive who's scan cannot be broken by the right circumstances.
It is how you recover from this mess that separates the men from the boys.
Judging from how little actual stick time airline pilots seem to be getting, I am amazed that loss of control incidents are not more prevalent.
The term scan as I am using it refers to the multi-sensory process of acquiring information regarding your flight from all sources. It is very close in meaning to situational awareness.
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JD-EE Now, what kind of chewing gum will you use to affix the front edge of the string to the window? I suspect common transparent tape would not do to well, nor would common duct tape. Umpty degrees below zero is not compatible with most adhesives I know that won't become a permanent part of the window.
tape will work very well, but also this: open the window, hold a lace out, close the window....... will fix it for a test
yes please
Last edited by grity; 31st Aug 2011 at 06:47.
vertical speed tape
Clandestino
Patterns on modern EFIS can be recognized without much cognitive effort and you might be surprised that Airbus EFIS does include VSI needle.
Patterns on modern EFIS can be recognized without much cognitive effort and you might be surprised that Airbus EFIS does include VSI needle.
And what is the picture, when vertical speed is greater then the display available?
Could somebody post a picture with VS pegged?
02:11:50 PF: ........"I have a problem, itīs that i donīt have vertical speed indications"
..............Captain: ."OK"
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Originally Posted by mm43
What do you believe the Alpha Max was at 02:10:56?
Last edited by HazelNuts39; 1st Sep 2011 at 18:58. Reason: DELETED: "I think it is only relevant in Normal law."
HazelNuts39
I can't explain the strange variations of cL and AoA after 02:10:56 when the airplane is evidently stalled.
I can't explain the strange variations of cL and AoA after 02:10:56 when the airplane is evidently stalled.
That doesn't explain that the sum of two wings, plus tail and fuselage looks like this.
In bank we loose lift on both wings, in a stalled environment with disturbed airflows anyway. Same with yaw. The bank reversal points correlate with the decrease in CL in that timeframe.
But iīm open for a better explanation.
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What are the limits, within those the VSI needle displays vertical speed?
And what is the picture, when vertical speed is greater then the display available?
Could somebody post a picture with VS pegged?
02:11:50 PF: ........"I have a problem, itīs that i donīt have vertical speed indications"
..............Captain: ."OK"
And what is the picture, when vertical speed is greater then the display available?
Could somebody post a picture with VS pegged?
02:11:50 PF: ........"I have a problem, itīs that i donīt have vertical speed indications"
..............Captain: ."OK"
Let's hope for a good answer... whatver it is
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@RetiredF4:
Thanks for your perspective on things...
I was catching-up with the thread yesterday after some time away, and I saw you mentioned the VSI / VVI a few days ago also. I've searched for the info on the VSI display, but can't find it yet.
I remember reading (I think in a BEA report?) that when some barometric parameters are exceeded (including CAS < some value???) that VSI display is inhibited and a flag was shown instead of a value. So there were times when the PF had no valid VSI shown (my memory is that NCD was set in the SSM of the ARINC data, to indicate it was not valid, but I'm happy to be corrected when the actual reference is found). I'll look again when I have a bit more time.
This might also be what is shown on the graphs in BEA report 3 (English) pages 106 and 111 (but that is not the presentation which I remember reading) - we can see that at times, the recorded VSI is shown switching to zero, then back again to a high value. At the times when the FDR trace records zero that will be NCD in the ARINC stream since, of course, the VSI was not really switching rapidly to zero and back to a high value.
Personally, I think this intermittent VSI indication also played a part in the PF's behaviour. As well as intermittent airspeed indication, he also had this intermittent VSI and, at some times, intermittent (counter-intuitive) stall warnings e.g. ND = stall warning, NU = no stall warning.
We now know that these behaviours all had a single cause (low CAS inhibits some data & warnings), but he/they may not have made that "connection" (and may not have been trained to know that). With 3 different sources of data all behaving "strangely" to him, (not only UAS) perhaps he simply did not know that he could (and should!) trust the artifical horizon?
At the moment, I'm not sure whether the PF (and PNF) didn't hear the repeated "Stall Stall" due to cognitive overload, or whether they heard it but chose to not believe it, thinking it to be spurious due to having other (apparently) incomprehensible indications as I mention above?
@Ian W:
Just wanted to also say thanks for the human factors comments, very interesting and fits with my experience about cognitive overload. I do also see a significant variation between people in this respect (I overload more quickly than some other people I know - I can't give commentary to an instructor in full sentences without the flying suffering
- but other people manage it fine!).
Thanks for your perspective on things...
What are the limits, within those the VSI needle displays vertical speed?
And what is the picture, when vertical speed is greater then the display available?
Could somebody post a picture with VS pegged?
02:11:50 PF: ........"I have a problem, itīs that i donīt have vertical speed indications"
..............Captain: ."OK"
And what is the picture, when vertical speed is greater then the display available?
Could somebody post a picture with VS pegged?
02:11:50 PF: ........"I have a problem, itīs that i donīt have vertical speed indications"
..............Captain: ."OK"
I remember reading (I think in a BEA report?) that when some barometric parameters are exceeded (including CAS < some value???) that VSI display is inhibited and a flag was shown instead of a value. So there were times when the PF had no valid VSI shown (my memory is that NCD was set in the SSM of the ARINC data, to indicate it was not valid, but I'm happy to be corrected when the actual reference is found). I'll look again when I have a bit more time.
This might also be what is shown on the graphs in BEA report 3 (English) pages 106 and 111 (but that is not the presentation which I remember reading) - we can see that at times, the recorded VSI is shown switching to zero, then back again to a high value. At the times when the FDR trace records zero that will be NCD in the ARINC stream since, of course, the VSI was not really switching rapidly to zero and back to a high value.
Personally, I think this intermittent VSI indication also played a part in the PF's behaviour. As well as intermittent airspeed indication, he also had this intermittent VSI and, at some times, intermittent (counter-intuitive) stall warnings e.g. ND = stall warning, NU = no stall warning.
We now know that these behaviours all had a single cause (low CAS inhibits some data & warnings), but he/they may not have made that "connection" (and may not have been trained to know that). With 3 different sources of data all behaving "strangely" to him, (not only UAS) perhaps he simply did not know that he could (and should!) trust the artifical horizon?
At the moment, I'm not sure whether the PF (and PNF) didn't hear the repeated "Stall Stall" due to cognitive overload, or whether they heard it but chose to not believe it, thinking it to be spurious due to having other (apparently) incomprehensible indications as I mention above?
@Ian W:
Just wanted to also say thanks for the human factors comments, very interesting and fits with my experience about cognitive overload. I do also see a significant variation between people in this respect (I overload more quickly than some other people I know - I can't give commentary to an instructor in full sentences without the flying suffering
- but other people manage it fine!).
Last edited by Diagnostic; 31st Aug 2011 at 10:32. Reason: Tried to improve grammar...
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Originally Posted by RetiredF4
What are the limits, within those the VSI needle displays vertical speed?