AF 447 Thread No. 6
Originally Posted by CONFiture
How stall warning didn't supercede that condition ... ?
If you'd like to suggest that stall warning should automatically stop the trim dead, it's a bad idea. If THS helped one get near or into the stall, last thing he needs is frozen trim - it must help one out of the edge of envelope too. I simply can not mention name of David Pettit Davies - a superb pilot, brilliant writer and overall a great man - enough times in this thread.
Originally Posted by jcjeant
So certainly with the insight of the AF447 accident you must think that the pilots were in very bad luck for have the 3 Pitot tubes frozen dead ..
Originally Posted by jcjeant
And also with the insight of AF447 accident .. you must think that if they avoided the CB plume by hundred miles .. the schedule was a joke .. but the passenggers and crew will be alive today .. commenting about their delay at arrival .....
Icing of the pitots was freak incident. Crew's reactions were unbelievable. Investigation moves into HF field.
There's excellent editorial in jul-aug issue of Aviation Safety World. Everyone, do yourselves a favour and read it.
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3Hole
Don't you see a problem with an aircraft with an automatic trim system that trims silently? For years we have had alerting devices on THS trim movement (clackers & whoolers) to let you know the thing is moving. Then comes the new guy on the block with a "better" idea. (Airbus)
Don't you see a problem with an aircraft with an automatic trim system that trims silently? For years we have had alerting devices on THS trim movement (clackers & whoolers) to let you know the thing is moving. Then comes the new guy on the block with a "better" idea. (Airbus)
But no one saw the trim move. No one heard it move. If they had thought about it, they should have anticipated it moving, but they had other problems and it bit them.
Had the trim movement kicked the crew in the rear or slapped them in the face for every degree it would have made no damn difference - they would have said yes trim me up, I'm trying to climb and the elevators aren't working... Had the THS ignored them and (say) gone to neutral, they would have overidden it with elevator all the way down. Had they had spotted it ignoring them, they would probably have manually trimmed back up (and what should the poor plane do then?). Why? Because they wanted to climb.
They were pitched up 15deg, falling out of the sky, plane not responding to controls [also low airspeed but they aren't sure on that]... and they had no clue they were stalled. Never mentioned. No (verbal) response to the stall warning - except perhaps "I’m in TOGA eh" [so I can't be stalled?] Throttles forward, stick hard back, why aren't we climbing ? "But we’ve got the engines what’s happening"
Sure, make the trim wheel clack, and in this case it's going to do all it's clacking during that 1min continuous stall warning. They didn't hear that, why would they hear the trim clack ?
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Sure, make the trim wheel clack, and in this case it's going to do all it's clacking during that 1min continuous stall warning. They didn't hear that, why would they hear the trim clack ?
But as RRR suggested, a stick shaker and even subsequently a pusher may have been the only way with that crew on that night, in that aircraft
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On Stall, Stall recovery and THS automation.
Clandestino,
I've read your recent posts with interest. I appreciate your sharing your experience and opinions.
Regarding the Stall, Stall Warning and THS, here are a number of clarifications:
As the operational recovery procedure from a Stall has been already revisited post AF 447 accident, there is a growing sentiment that it is time, for a closer look based on AF 447 data, and prior data as well, also to the automation being involved prior and during Stall, involving such elements as THS - the AF 447 case is bringing additional elements to those existing from previous incidents, documented by BEA reports.
BEA reports of incidents involving Airbus Stalls show that often the Stall Warning was active in parallel with the Autotrim moving the THS in max NU position, so the AF 447 case is not unique.
In some of the few Stalls that were followed by successful recovery, the BEA reports show that pilots struggled aggressively and valiantly with the combination Autotrimmed THS at max NU + Elevators max ND, which was a considerable obstacle to defeat.
On reflecting, it seems that in a Stall, a THS max NU, if anything, is only diminishing or delaying the effect of the Elevators ND, at a time, when the effectiveness of the Elevator ND is crucial and has stringent time constraints.
A successful Stall recovery involves a transition from Stall/NU, to ND with Elevators ND to regain speed, with loss of altitude, followed by Elevators NU, to level, and than regain altitude. It seems that in such conditions, having the THS stable in an Optimal Position from a Stall Recovery perspective - the Neutral position - which makes Elevator NU, or ND more deterministic, is a much better choice than having it move slowly from one position to another, under automation control, at times when the effects of Elevator ND, and/or NU have to be maximum and immediate, and are under very stringent time interval constraints.
It is more and more clear (to me) that the THS has a slow, longer time range stabilization function, which does not fit well with the short duration and requirements of quick transitions from NU/Stall, to ND and than NU during the Stall recovery, therefore, it is much better to have it neutral during these transitions.
Lastly, the suggestion that seems to have circulated during the past several pages regarding the THS at Stall is that it should be brought automatically to the Optimal Position for Stall recovery - Neutral Position - as opposed to being stopped in its current position, whatever that may be - which seems to be your understanding of the suggestion.
I've read your recent posts with interest. I appreciate your sharing your experience and opinions.
Regarding the Stall, Stall Warning and THS, here are a number of clarifications:
As the operational recovery procedure from a Stall has been already revisited post AF 447 accident, there is a growing sentiment that it is time, for a closer look based on AF 447 data, and prior data as well, also to the automation being involved prior and during Stall, involving such elements as THS - the AF 447 case is bringing additional elements to those existing from previous incidents, documented by BEA reports.
BEA reports of incidents involving Airbus Stalls show that often the Stall Warning was active in parallel with the Autotrim moving the THS in max NU position, so the AF 447 case is not unique.
In some of the few Stalls that were followed by successful recovery, the BEA reports show that pilots struggled aggressively and valiantly with the combination Autotrimmed THS at max NU + Elevators max ND, which was a considerable obstacle to defeat.
On reflecting, it seems that in a Stall, a THS max NU, if anything, is only diminishing or delaying the effect of the Elevators ND, at a time, when the effectiveness of the Elevator ND is crucial and has stringent time constraints.
A successful Stall recovery involves a transition from Stall/NU, to ND with Elevators ND to regain speed, with loss of altitude, followed by Elevators NU, to level, and than regain altitude. It seems that in such conditions, having the THS stable in an Optimal Position from a Stall Recovery perspective - the Neutral position - which makes Elevator NU, or ND more deterministic, is a much better choice than having it move slowly from one position to another, under automation control, at times when the effects of Elevator ND, and/or NU have to be maximum and immediate, and are under very stringent time interval constraints.
It is more and more clear (to me) that the THS has a slow, longer time range stabilization function, which does not fit well with the short duration and requirements of quick transitions from NU/Stall, to ND and than NU during the Stall recovery, therefore, it is much better to have it neutral during these transitions.
Lastly, the suggestion that seems to have circulated during the past several pages regarding the THS at Stall is that it should be brought automatically to the Optimal Position for Stall recovery - Neutral Position - as opposed to being stopped in its current position, whatever that may be - which seems to be your understanding of the suggestion.
That question should be and will be forwarded to human factors experts.
If you'd like to suggest that stall warning should automatically stop the trim dead, it's a bad idea. If THS helped one get near or into the stall, last thing he needs is frozen trim - it must help one out of the edge of envelope too.
If you'd like to suggest that stall warning should automatically stop the trim dead, it's a bad idea. If THS helped one get near or into the stall, last thing he needs is frozen trim - it must help one out of the edge of envelope too.
Last edited by airtren; 19th Aug 2011 at 02:57.
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Hi Infrequent,
So you are planning to tape over any trim-in-motion bicycle bells that they stick in your Airbus cockpit because you don't want to have a clue?
The AF447 PF may have been completely clueless, but if either the PNF or Captain had tumbled to the trim position, do you really think they would have persisted in ignoring the possibility of stall? You have to give people a chance to get the information they need, even if their attention is distracted elsewhere. Stealth change in the position of a major control surface is downright hazardous.
Safetypee recently posted some interesting links. One of these is an excellent paper by Donald A. Norman titled, "THE PROBLEM OF AUTOMATION" http://www.jnd.org/dn.mss/Norman-overautomation.pdf
One of the paragraph titles sums up a key element of the problem: "THE PROBLEM IS NOT AUTOMATION, IT IS LACK OF FEEDBACK."
Do you remember the FBW pilot's favorite question? "Whats it doing now?"
That is the issue. The Airbus does not speak or gesture very effectively. How can flight crews maintain understanding of what their aircraft is up to? How do we keep the crew in the loop?
So you are planning to tape over any trim-in-motion bicycle bells that they stick in your Airbus cockpit because you don't want to have a clue?
The AF447 PF may have been completely clueless, but if either the PNF or Captain had tumbled to the trim position, do you really think they would have persisted in ignoring the possibility of stall? You have to give people a chance to get the information they need, even if their attention is distracted elsewhere. Stealth change in the position of a major control surface is downright hazardous.
Safetypee recently posted some interesting links. One of these is an excellent paper by Donald A. Norman titled, "THE PROBLEM OF AUTOMATION" http://www.jnd.org/dn.mss/Norman-overautomation.pdf
One of the paragraph titles sums up a key element of the problem: "THE PROBLEM IS NOT AUTOMATION, IT IS LACK OF FEEDBACK."
Do you remember the FBW pilot's favorite question? "Whats it doing now?"
That is the issue. The Airbus does not speak or gesture very effectively. How can flight crews maintain understanding of what their aircraft is up to? How do we keep the crew in the loop?
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I can see no reasonable means of engineering a system which would "reposition" the THS as a result of being in a detected "stall".
The whole point of being in a degraded mode with reduced or no envelope protection is that the system can no longer rely on one of its primary protection inputs - alpha.
if, despite that lack of reliability in alpha the system were, in a degraded mode, to have authority to move the most power single surface on the aircraft through close to full authority ( NU to neutral is a LONG way) it would be utterly impossible to show the system as being safe - in the event of an erroneous AOA input, you'd still be exposed to a large stab runaway, in effect.
With the AOA reliability suspect, the system can no longer act, automatically, on AOA. All it can do is draw the attention of the crew to the apparent high AOA situation - shake, shake - and hope they, with their human reasoning and airmanship, can resolve the situation which is outside the design parameters of the FBW system.
Unfortunately, in this case, they couldn't or didn't.
The whole point of being in a degraded mode with reduced or no envelope protection is that the system can no longer rely on one of its primary protection inputs - alpha.
if, despite that lack of reliability in alpha the system were, in a degraded mode, to have authority to move the most power single surface on the aircraft through close to full authority ( NU to neutral is a LONG way) it would be utterly impossible to show the system as being safe - in the event of an erroneous AOA input, you'd still be exposed to a large stab runaway, in effect.
With the AOA reliability suspect, the system can no longer act, automatically, on AOA. All it can do is draw the attention of the crew to the apparent high AOA situation - shake, shake - and hope they, with their human reasoning and airmanship, can resolve the situation which is outside the design parameters of the FBW system.
Unfortunately, in this case, they couldn't or didn't.
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MadScientist
Surely alpha AoA is NOT suspect in Alt2 degraded mode. In fact AoA is (or should be) one of the easiest and most reliable of all transducers and can easily be kept independent.. that's why I find that a fully dynamically balanced vane was black-balled below 60 kts... It should never be black-balled... it should be extremely lightly spring loaded to a nominal 0 or 2,3 degrees +ve - for a low speed oscillating case, an RMS value could be used, and finally disregarded if mean and peak vales exceed a given ratio... for airspeed to be in any way involevd in its output IMHO is wrong.
There are also fairly easy ways to measure AoA less accurately as a fall-back value, electronically using hot-wire anemometry, as well as other methods
Surely alpha AoA is NOT suspect in Alt2 degraded mode. In fact AoA is (or should be) one of the easiest and most reliable of all transducers and can easily be kept independent.. that's why I find that a fully dynamically balanced vane was black-balled below 60 kts... It should never be black-balled... it should be extremely lightly spring loaded to a nominal 0 or 2,3 degrees +ve - for a low speed oscillating case, an RMS value could be used, and finally disregarded if mean and peak vales exceed a given ratio... for airspeed to be in any way involevd in its output IMHO is wrong.
There are also fairly easy ways to measure AoA less accurately as a fall-back value, electronically using hot-wire anemometry, as well as other methods
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So, bear with me. Say the Bus had gone to DIRECT LAW. There was a contingent not that long ago pushing that position.
TRIM is out of the picture, (Only manual, and they didn't notice it in AL)
A Stall surely, and a recovery with or without the PF's stick. He picked up the Roll pretty quickly, would he have grokked the situation in DIRECT? Would he have held Back ss through the 14 or so phugae? Or would he have recovered. Probably a dumb question. Except... in DIRECT, TRIM is optional. This STALL entry was unconventional... they never felt the joy of the nose dropping like a rock.
The Bus flies pretty well in the Stall......
TRIM is out of the picture, (Only manual, and they didn't notice it in AL)
A Stall surely, and a recovery with or without the PF's stick. He picked up the Roll pretty quickly, would he have grokked the situation in DIRECT? Would he have held Back ss through the 14 or so phugae? Or would he have recovered. Probably a dumb question. Except... in DIRECT, TRIM is optional. This STALL entry was unconventional... they never felt the joy of the nose dropping like a rock.
The Bus flies pretty well in the Stall......
MFS, (agreeing with HM # 145), in this instance the AoA input might have been affected by a suspect ADIRU; there is no evidence of that, but there is valid supposition that the crew disbelieved the AoA derived stall warning.
However, the irony is that the requirements for an independent highly reliable stall system warning implies that AoA would be available for both stall warning and THS reposition – even an auto stall recovery (akin to a super stick push). The mechanism might be similar to existing Mach trim functions in the flight control computer.
However, the irony is that the requirements for an independent highly reliable stall system warning implies that AoA would be available for both stall warning and THS reposition – even an auto stall recovery (akin to a super stick push). The mechanism might be similar to existing Mach trim functions in the flight control computer.
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MadScientist,
With the AF 447 BEA Report at hand:
Based on the BEA graphs, in the AF 447 case, the start of the Autotrim THS move towards max NU coincides (pretty much) with the start of the constant/continuous 53 seconds Stall Warning. During that period, from the beginning and close to its end - perhaps for about 40 seconds, the graphs also show NON-oscilatting (i.e. stable) AOAs emitted by IRSi(i=1,2,3) (page 111).
In this case, the system didn't really have to move the THS, it only had to stop the Autotrim from moving it from its -3 degrees position.
Back to the suggestion, perhaps there is a misunderstanding.
The suggestion in essence was not intended as to provide more automation during a Stall, but rather slightly change it, by reducing or eliminating the automation of the THS, in association with placing the THS in the "most optimal" position for the Stall Recovery. What the latter means, in terms of "optimal position" can certainly be the subject of more studying, but as a start can be considered THS Neutral.
Lastly, resolving the stability of the Stall Warning may provide the additional stability for the THS mechanism.
With the AF 447 BEA Report at hand:
Based on the BEA graphs, in the AF 447 case, the start of the Autotrim THS move towards max NU coincides (pretty much) with the start of the constant/continuous 53 seconds Stall Warning. During that period, from the beginning and close to its end - perhaps for about 40 seconds, the graphs also show NON-oscilatting (i.e. stable) AOAs emitted by IRSi(i=1,2,3) (page 111).
In this case, the system didn't really have to move the THS, it only had to stop the Autotrim from moving it from its -3 degrees position.
Back to the suggestion, perhaps there is a misunderstanding.
The suggestion in essence was not intended as to provide more automation during a Stall, but rather slightly change it, by reducing or eliminating the automation of the THS, in association with placing the THS in the "most optimal" position for the Stall Recovery. What the latter means, in terms of "optimal position" can certainly be the subject of more studying, but as a start can be considered THS Neutral.
Lastly, resolving the stability of the Stall Warning may provide the additional stability for the THS mechanism.
I can see no reasonable means of engineering a system which would "reposition" the THS as a result of being in a detected "stall".
The whole point of being in a degraded mode with reduced or no envelope protection is that the system can no longer rely on one of its primary protection inputs - alpha.
if, despite that lack of reliability in alpha the system were, in a degraded mode, to have authority to move the most power single surface on the aircraft through close to full authority ( NU to neutral is a LONG way) it would be utterly impossible to show the system as being safe - in the event of an erroneous AOA input, you'd still be exposed to a large stab runaway, in effect.
With the AOA reliability suspect, the system can no longer act, automatically, on AOA. All it can do is draw the attention of the crew to the apparent high AOA situation - shake, shake - and hope they, with their human reasoning and airmanship, can resolve the situation which is outside the design parameters of the FBW system.
Unfortunately, in this case, they couldn't or didn't.
The whole point of being in a degraded mode with reduced or no envelope protection is that the system can no longer rely on one of its primary protection inputs - alpha.
if, despite that lack of reliability in alpha the system were, in a degraded mode, to have authority to move the most power single surface on the aircraft through close to full authority ( NU to neutral is a LONG way) it would be utterly impossible to show the system as being safe - in the event of an erroneous AOA input, you'd still be exposed to a large stab runaway, in effect.
With the AOA reliability suspect, the system can no longer act, automatically, on AOA. All it can do is draw the attention of the crew to the apparent high AOA situation - shake, shake - and hope they, with their human reasoning and airmanship, can resolve the situation which is outside the design parameters of the FBW system.
Unfortunately, in this case, they couldn't or didn't.
Last edited by airtren; 19th Aug 2011 at 12:37.
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Lyman;
I am not sure how ACARS would report the FPV not working. I suppose it is possible. The Bird is not a "thing", it is calculated from the IRUs, and represents the course, both vertically and
horizontally, that the aircraft is moving. It is completely unrelated to any pitot static system, and does not rely on AOA measurements either. There are 3 IRU's on a 320 (maybe one more on a 330?). Any one of them could calculate the FPV.
The ACARS could report that the IRU's were not working, which would mean the FPV is not working, but I don't remember that from the data that I have read. It was only pitot-static information that was bad, for a short time, during the accident. At least that is what I have read thus far.
I flew 3 different jet aircraft with AOA as the primary performance instrument. The last one also had a HUD with the FPV. The great thing about the FPV on a PFD is that it gives you instantaneous information, including AOA, irrespective of what is going on with the pitot static instruments, and does not require any additional "scan" . It is where you are looking most of the time anyway.
I am not sure how ACARS would report the FPV not working. I suppose it is possible. The Bird is not a "thing", it is calculated from the IRUs, and represents the course, both vertically and
horizontally, that the aircraft is moving. It is completely unrelated to any pitot static system, and does not rely on AOA measurements either. There are 3 IRU's on a 320 (maybe one more on a 330?). Any one of them could calculate the FPV.
The ACARS could report that the IRU's were not working, which would mean the FPV is not working, but I don't remember that from the data that I have read. It was only pitot-static information that was bad, for a short time, during the accident. At least that is what I have read thus far.
I flew 3 different jet aircraft with AOA as the primary performance instrument. The last one also had a HUD with the FPV. The great thing about the FPV on a PFD is that it gives you instantaneous information, including AOA, irrespective of what is going on with the pitot static instruments, and does not require any additional "scan" . It is where you are looking most of the time anyway.
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Hi USMCProbe,
Most of the time - it is turned off because the SOP is to use FDs. If you turn the FDs off, you then have to press another button to turn the PFV on.
If you are stalled, (with AoA in excess of 45 degs) it will be out of view (off scale below the visible part of the the PFD).
Apart from that - it's very simple to use.
It is where you are looking most of the time anyway.
If you are stalled, (with AoA in excess of 45 degs) it will be out of view (off scale below the visible part of the the PFD).
Apart from that - it's very simple to use.
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Exactly my point. If it is more than 8-10 degrees down from the pitch bars, your AOA is too high. Push forward until it is 2-7 degrees and keep it there. If it is "PFD-limited" i.e. off scale at the bottom, you are most definitely stalled.
And yes most of the time the "bird" is off , but they had over 3 minutes to hit the button and call it up. They were not trained to do this, and it would have probably saved the plane if they had been.
I would like to hear more about the ACARS report saying that the FPV was not working. Does anybody have any info on this? I can't believe a software generated symbol would be "monitored" and reported. The IRU's yes, almost for sure.
And yes most of the time the "bird" is off , but they had over 3 minutes to hit the button and call it up. They were not trained to do this, and it would have probably saved the plane if they had been.
I would like to hear more about the ACARS report saying that the FPV was not working. Does anybody have any info on this? I can't believe a software generated symbol would be "monitored" and reported. The IRU's yes, almost for sure.
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Hi
I agree with the first of your ideas (reduce or eliminate the automation of the THS) but not with the second part (repositionning the THS to neutral when stall warning is ON), as I feel unconfortable with this last idea.
Why not "simply" prevent any further NU movement of the THS by the auto-trim while the stall warning is ON ? This way :
- you prevent the automation to make the situation harder/longer to solve (THS full up = reduced ND effectivness = bad when stalled)
- but you don't inhibit/freeze totally the auto-trim (if you apply enough ND stick, the THS will eventually move ND too)
- you don't prevent the crew to manually apply (trim wheel) more NU or ND trim depending on their assessment of the situation
- you don't add another alarm (USE MAN PITCH TRIM type) to an already stressed crew to process.
Am I missing something?
I'm not sure that it will have changed anything substential in AF447's case, but I thought it was worth thinking about it.
On a side note, re the clues the crew had about the THS position : There was the trim wheel index, but also the F/CTL page on the center screen (showing all the control surfaces state, including numerical value for the THS angle). That page was automatically called due to some of the failures AF447 encountered (see ACARS analysis in interim reports #1 & #2).
It was not enough for the crew to notice. Sensory overload I guess?
I then support the idea of a clicking trim wheel, as it may give "another chance" to notice.
The suggestion in essence was not intended as to provide more automation, or a different automation during a Stall, but rather reduce or eliminate the automation of the THS, in association with placing the THS in the "most optimal" position for the Stall Recovery. What the latter means, in terms of "optimal position" can certainly be the subject of more studying, but as a start can be considered THS Neutral.
Why not "simply" prevent any further NU movement of the THS by the auto-trim while the stall warning is ON ? This way :
- you prevent the automation to make the situation harder/longer to solve (THS full up = reduced ND effectivness = bad when stalled)
- but you don't inhibit/freeze totally the auto-trim (if you apply enough ND stick, the THS will eventually move ND too)
- you don't prevent the crew to manually apply (trim wheel) more NU or ND trim depending on their assessment of the situation
- you don't add another alarm (USE MAN PITCH TRIM type) to an already stressed crew to process.
Am I missing something?
I'm not sure that it will have changed anything substential in AF447's case, but I thought it was worth thinking about it.
On a side note, re the clues the crew had about the THS position : There was the trim wheel index, but also the F/CTL page on the center screen (showing all the control surfaces state, including numerical value for the THS angle). That page was automatically called due to some of the failures AF447 encountered (see ACARS analysis in interim reports #1 & #2).
It was not enough for the crew to notice. Sensory overload I guess?
I then support the idea of a clicking trim wheel, as it may give "another chance" to notice.
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FLAG ON CAPT PFD FPV and FLAG ON F/O PFD FPV (2 h 11)
Symptoms:
Disappearance of the FPV (bird) on the PFDs, Captain and First Officer sides, and display of the corresponding flag.
Meaning:
This message indicates that the flight path vector (FPV) function is selected but unavailable. In order to lose completely this function, which is elaborated by the three IRs, in a way that is compatible with the CFR, one of the following three conditions must be met for each ADR:
¤ barometric vertical speed higher, as an absolute value, than 20,000 ft/min,
¤ true air speed higher than 599 kt,
¤ measured calibrated airspeed lower than 60 kt.
Once the operating conditions are satisfied again, the FPVs reappear on the PFD (if TRK/FPA mode is still selected).
Symptoms:
Disappearance of the FPV (bird) on the PFDs, Captain and First Officer sides, and display of the corresponding flag.
Meaning:
This message indicates that the flight path vector (FPV) function is selected but unavailable. In order to lose completely this function, which is elaborated by the three IRs, in a way that is compatible with the CFR, one of the following three conditions must be met for each ADR:
¤ barometric vertical speed higher, as an absolute value, than 20,000 ft/min,
¤ true air speed higher than 599 kt,
¤ measured calibrated airspeed lower than 60 kt.
Once the operating conditions are satisfied again, the FPVs reappear on the PFD (if TRK/FPA mode is still selected).
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Hi AZR,
Thanks for the reference.
So despite being airborne (no weight on wheels, RAD Alts > 0 etc.) AB designed a system which removed both the stall warning and the FPV when IAS<60 kts.
What a wonderful system.
Thanks for the reference.
So despite being airborne (no weight on wheels, RAD Alts > 0 etc.) AB designed a system which removed both the stall warning and the FPV when IAS<60 kts.
What a wonderful system.
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Originally Posted by Clandestino
Trick is to have each and every airline pilot remember them and perform them flawlessly when his body clock says its 4AM, when he's jet-lagged, when he hasn't handflown the plane above FL100 for ages (if ever), when he does less than half a dozen manual landings per month, when he has never experienced control laws degradation and protection loss in real life and only seldom in simulator, when his knowledge of the principles of flight is lacking as he was only made to memorize the multiple choice answers to pass ATPL exams, etc... Whoever patents practical solution to this problem will quickly become millionaire.
When the auto-throttle and auto-pilot disconnect and Otto says meatware has the plane PF should start to execute the correct (UAS) drill AND PNF should start reading out the procedure to be checked off one by one. The PNF should call it out loud and clear. PF should repeat loud and clear.
If they face a memory drill, PF may act, but PNF must call out the memory procedure and PF must acknowledge with the full step's instructions. Then you have two human brains working on the same problem in case one flies South for the winter or something. If PF fails to acknowledge PNF swats him over the head with two day old pizzas. If PNF fails to call out the drill, PF shouts obscenities about his 33rd cousin's maiden aunt - anything to get the communications cycle running with check and cross check.
It's so darned simple it's not even patentable.
I tell you three times, Communicate, Communicate, Communicate. Therefore it must be true. (Sorry Mr. Carroll for mangling it. But, as a dirty job it had to be done.)
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Hi JD-EE,
I agree when conducted in a calm, relaxed atmosphere. Verbal communications on top of the plethora of cockpit noises, causes some noises to be filtered out. (Stall Stall??).
The big advantage of connected control wheels, is Pilot A Knows what Pilot B is attempting to do without a word being spoken.
AB have designed a flight deck where the crew are separated by their control sticks. They may as well be in separate rooms talking to each other on the telephone whilst watching their individual Flight Displays.
Communications is the solution.
The big advantage of connected control wheels, is Pilot A Knows what Pilot B is attempting to do without a word being spoken.
AB have designed a flight deck where the crew are separated by their control sticks. They may as well be in separate rooms talking to each other on the telephone whilst watching their individual Flight Displays.
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Lone, if the plane has been showing a ground speed of say 475 kts and an airspeed of 275 kts. The airspeed goes away because somebody insulted the pitot probes. If the ground speed drops but stays above 200 kts should the plane decide it doesn't know AIR speed so it should not impolitely sneer at the pilot about the plane stalling? Seriously, simple loss of airspeed is not a total loss of the ability to make a usable guess of airspeed for at least a few minutes with regards to stall warnings in a sane world.
Unfortunately, in the case at hand, I really don't think that would have made a difference. PF lost his head through lacunae in his training, unrecognized fatigue, or some other factor we can only guess about. PNF was not being communicative enough calling out proper procedure so that the cockpit TEAM were working on the same problem with their full brains. (And don't forget that two day old pizza for waking up the PF.)
Unfortunately, in the case at hand, I really don't think that would have made a difference. PF lost his head through lacunae in his training, unrecognized fatigue, or some other factor we can only guess about. PNF was not being communicative enough calling out proper procedure so that the cockpit TEAM were working on the same problem with their full brains. (And don't forget that two day old pizza for waking up the PF.)
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A33Zab quoted: The altitude indications are based on GPS data. Two amber dashes cover the last two digits because the GPS altitude is less accurate than the barometric altitude.
I can (sort of) understand that back when the Denial Of Accuracy or dithering or whatever you want to call it was enabled by default on GPS. 100 meters was about as good as it got. Now it's about 10 times better between the DOA going away (I had a paw or two in that design) and basic improvements in clock and ephemeris accuracy. I wonder if TPTB have recognized this and given GPS a slightly better reputation and treatment.
Of course, I am presuming they have the intertial platform providing aiding data to the GPS receiver to help it track through extreme turbulence and other high dynamics conditions.
I can (sort of) understand that back when the Denial Of Accuracy or dithering or whatever you want to call it was enabled by default on GPS. 100 meters was about as good as it got. Now it's about 10 times better between the DOA going away (I had a paw or two in that design) and basic improvements in clock and ephemeris accuracy. I wonder if TPTB have recognized this and given GPS a slightly better reputation and treatment.
Of course, I am presuming they have the intertial platform providing aiding data to the GPS receiver to help it track through extreme turbulence and other high dynamics conditions.