AF 447 Thread No. 6
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And I agree that does not mean that analogue gauges are always right - I lost a friend due to a misread of an old 3 needle analogue altimeter.
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mm43,
I think you're right.... too many people read too much into the translations.
HarryMann,
"an old 3 needle analogue altimeter".
IIRC, they killed several people....
IMHO, the combined 'drum' (for the 'real figure') and one 'needle' (for the 'trend') instrument was the best solution.
I'm not sure whether the current PFD implementation is "as good".
I would like to see pilots' opinions on that, but if anything it's slightly O/T.
I think you're right.... too many people read too much into the translations.
HarryMann,
"an old 3 needle analogue altimeter".
IIRC, they killed several people....
IMHO, the combined 'drum' (for the 'real figure') and one 'needle' (for the 'trend') instrument was the best solution.
I'm not sure whether the current PFD implementation is "as good".
I would like to see pilots' opinions on that, but if anything it's slightly O/T.
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Hi DozyWannabe,
PF takes manual control at 2.10.06.
From 2.10.7 - 18
"The copilot sidestick is positioned:
- nose-up between neutral and ¾ of the stop position
- to the left in half-travel position then to the right in half-travel position and twice, alternatively left to the stop position then right to the half-travel position (Period of 4 seconds)."
2.11.00 PNF says "Above all try to touch the lateral controls as little as possible eh"
PNF was either happy with PF's inputs for nearly 1 minute (doubtful) or unaware of the over controlling inputs.
That is one of the major disadvantages of separate Side Stick design.
... but if that is the case then why do we have the references to going up when they should be going down and to touch the lateral controls as gently as possible by the PNF?
From 2.10.7 - 18
"The copilot sidestick is positioned:
- nose-up between neutral and ¾ of the stop position
- to the left in half-travel position then to the right in half-travel position and twice, alternatively left to the stop position then right to the half-travel position (Period of 4 seconds)."
2.11.00 PNF says "Above all try to touch the lateral controls as little as possible eh"
PNF was either happy with PF's inputs for nearly 1 minute (doubtful) or unaware of the over controlling inputs.
That is one of the major disadvantages of separate Side Stick design.
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He starts giving guidance to the PF ("Watch your speed") at 2:10:27, so if he had his head down in the ECAM it wasn't for any more than 22 seconds, certainly less than a minute.
He starts making comments on the PF's flight path ("Stabilise, Go back down (descend)") between 2:10:28 and 2:10:31 - so he's starting to sound unhappy about 25 seconds after the PF takes control. He makes a direct reference to lateral controls at 2:11:00, as you say - but he's clearly aware that something's not right 30 seconds before that.
Remember that the rules state that the non-relief pilot is not to take control without the Captain's say-so under most conditions. This wasn't specific to AF's Airbus crews, it was fleet-wide.
He starts making comments on the PF's flight path ("Stabilise, Go back down (descend)") between 2:10:28 and 2:10:31 - so he's starting to sound unhappy about 25 seconds after the PF takes control. He makes a direct reference to lateral controls at 2:11:00, as you say - but he's clearly aware that something's not right 30 seconds before that.
Remember that the rules state that the non-relief pilot is not to take control without the Captain's say-so under most conditions. This wasn't specific to AF's Airbus crews, it was fleet-wide.
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Hope this is a helpful chart...made it for my use but figure others may benefit. I cut out the traces I wanted to analyze together and put them into one larger file. The yellow highlight is time when the stall alarm was active. Made it by superimposing the BEA trace of the stall alarm. I eyeballed the times on the quotes with larger lines indicating multiple seconds of conversation as detailed in the BEA report. Any errors, let me know.
PuraVidaTransport
It looks like the biggest error was the image hosting service you are using. I got some interesting re-directs to XXXXXX sites
But was finally able to capture your hard work so here it is for anybody else
Hope this is a helpful chart...made it for my use but figure others may benefit. I cut out the traces I wanted to analyze together and put them into one larger file. The yellow highlight is time when the stall alarm was active. Made it by superimposing the BEA trace of the stall alarm. I eyeballed the times on the quotes with larger lines indicating multiple seconds of conversation as detailed in the BEA report. Any errors, let me know.
But was finally able to capture your hard work so here it is for anybody else
RE:
Though I agree with much of what you say in the post that contains the above quote (and other posts you've made), I have some difficulty with your assertions -- based on the facts as we know them so far -- that: A. The aircraft's instrumentation (or lack thereof) was not a contributing factor, and B. The source of the PF's actions was "panic".
If we are investigating accidents today for the purpose of learning lessons so as to avoid, or minimise the chances of, making the same mistakes again, we have to be very careful not to over simplify what happened and why; especially when it comes to the human. Of course the actions of the PF (primarily), the PNF (a close second), and even the Captain, are the prime "causes" (in terms of specific actions at the time) of the loss of the aircraft. But, if you are saying that there is nothing to be learned here about instrumentation, display presentation, and human behaviour, in addition to your points about AF procedures and training, I think you're missing out on the notion that the ultimate goal of investigators is to try to get as close as possible to the "why" (actually "why's"). In that light I believe there is more we can learn from this event, including in the areas of displays, warnings, controls, etc; as well as the obvious ones such as CRM, procedures and training (both in terms of AF specifically and industry wide).
Too many people are grasping at straws and thinking that somehow the machine or the warnings had a big impact on the accident. It didn't, the PF was the one who made the NU inputs and it wasn't because of cognitive overload and not hearing the stall warnings - there were three pilots. The PF panicked and went into shock pulling back on the stick. That's all there is to it
If we are investigating accidents today for the purpose of learning lessons so as to avoid, or minimise the chances of, making the same mistakes again, we have to be very careful not to over simplify what happened and why; especially when it comes to the human. Of course the actions of the PF (primarily), the PNF (a close second), and even the Captain, are the prime "causes" (in terms of specific actions at the time) of the loss of the aircraft. But, if you are saying that there is nothing to be learned here about instrumentation, display presentation, and human behaviour, in addition to your points about AF procedures and training, I think you're missing out on the notion that the ultimate goal of investigators is to try to get as close as possible to the "why" (actually "why's"). In that light I believe there is more we can learn from this event, including in the areas of displays, warnings, controls, etc; as well as the obvious ones such as CRM, procedures and training (both in terms of AF specifically and industry wide).
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OOPPSS...
Sorry about that Lomo, the three or four times I checked it (and even now), never saw any porn or links to porn. Perhaps the link I used just works for me and my cookies OR you have some "interesting" cookies of your own 
If you will PM me (or perhaps a moderator) with the url that you used to fix the problem, I will edit my original post.
Be honest, I just did a Google search for an image host after noticing I couldn't just attach a photo file here. Found that one (postimage.org) first and admit, know nothing about them...all my fault and my apologies to any offended.
If you will PM me (or perhaps a moderator) with the url that you used to fix the problem, I will edit my original post.
Be honest, I just did a Google search for an image host after noticing I couldn't just attach a photo file here. Found that one (postimage.org) first and admit, know nothing about them...all my fault and my apologies to any offended.
Last edited by PuraVidaTransport; 30th Aug 2011 at 03:16. Reason: Addition...
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Grizzled
The perceived existence of a problem with instrumentation or displays misses the point. Humans have been misinterpreting instrumentation since it started being used and with any redesign (which may indeed be welcome) you will find that someone will find a way to misinterpret it. Can it be improved? - well, yes, everything can always be improved. Will it eliminate accidents like this one? - highly unlikely. It's just this, know what you are using and what it tells you.
One must also be careful not to attribute any negative connotation to the term 'panic' which was used in a purely technical sense. The nature of the state of panic and of acute stress disorder (shock - which are what I believe happened to the PF) include a form of tunnel vision in which almost every other stimulus or input is excluded except that which the person in the situation chooses to focus on. This kind of reaction shuts down verbal cognitive channels pretty effectively. It can be countered by reliance on procedures - following the procedures is a very good way of getting out of the state. The other option is training. If you are well trained you are less likely to be prone to this type of reaction (Hard training, easy execution).
With the PF though I am very sceptical that improved or different displays would have changed his reaction though this can never be known for certain. Knowing his machine more thoroughly and following the SOPs coupled with sound CRM would have been more likely to help the crew avoid the accident. Flight deck management procedure strikes me as a bit too casual. The cultural issues that arise though are much more complex - the physics or aviation issues are fairly easy to understand. However, the human factors need much more careful consideration than I believe they have been given by AF (I do believe we are on the same page on this).
Whatever the level of automation, the pilot is the person responsible for his aircraft and needs to understand and react appropriately. The airline needs to ensure that the pilot is given the support and training to do so and the CPD (Continuing Professional Development) throughout their career. The automation logic employed by Airbus is to my mind perfectly logical and suited for the environment it operates in. In certain circumstances it does remove itself but those are conditions for which it would be inappropriate. It is designed as an aid not as a replacement but it does look as if some pilots and some airlines are treating it as the latter not the former. This I need hardly mention is dangerous.
The perceived existence of a problem with instrumentation or displays misses the point. Humans have been misinterpreting instrumentation since it started being used and with any redesign (which may indeed be welcome) you will find that someone will find a way to misinterpret it. Can it be improved? - well, yes, everything can always be improved. Will it eliminate accidents like this one? - highly unlikely. It's just this, know what you are using and what it tells you.
One must also be careful not to attribute any negative connotation to the term 'panic' which was used in a purely technical sense. The nature of the state of panic and of acute stress disorder (shock - which are what I believe happened to the PF) include a form of tunnel vision in which almost every other stimulus or input is excluded except that which the person in the situation chooses to focus on. This kind of reaction shuts down verbal cognitive channels pretty effectively. It can be countered by reliance on procedures - following the procedures is a very good way of getting out of the state. The other option is training. If you are well trained you are less likely to be prone to this type of reaction (Hard training, easy execution).
With the PF though I am very sceptical that improved or different displays would have changed his reaction though this can never be known for certain. Knowing his machine more thoroughly and following the SOPs coupled with sound CRM would have been more likely to help the crew avoid the accident. Flight deck management procedure strikes me as a bit too casual. The cultural issues that arise though are much more complex - the physics or aviation issues are fairly easy to understand. However, the human factors need much more careful consideration than I believe they have been given by AF (I do believe we are on the same page on this).
Whatever the level of automation, the pilot is the person responsible for his aircraft and needs to understand and react appropriately. The airline needs to ensure that the pilot is given the support and training to do so and the CPD (Continuing Professional Development) throughout their career. The automation logic employed by Airbus is to my mind perfectly logical and suited for the environment it operates in. In certain circumstances it does remove itself but those are conditions for which it would be inappropriate. It is designed as an aid not as a replacement but it does look as if some pilots and some airlines are treating it as the latter not the former. This I need hardly mention is dangerous.
Well said; as you say, we are on the same page on most points I think.
I too believe that "culture" in this case played a most significant role. And I use that word in all the senses it is used in today's Safety Management writings: national, corporate and professional.
Re your last point:
On that, I could not agree more. Many aviation safety professionals are suggesting (rightfully, IMHO) that we are just now seeing the beginning of the next major "trend" in accidents, which can generally be described as: LOC incidents resulting from a (widening) gap between what is required from the crew in an emergency situation involving loss of some significant aspect or component of computerization or FBW, and what the crew is adequately / appropriately trained for and experienced in doing.
I too believe that "culture" in this case played a most significant role. And I use that word in all the senses it is used in today's Safety Management writings: national, corporate and professional.
Re your last point:
It is designed as an aid not as a replacement but it does look as if some pilots and some airlines are treating it as the latter not the former. This I need hardly mention is dangerous.
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The following is a combination of FDR traces posted in a format used to convey the data that HazelNuts39 had originally constructed from the BEA's initial report on the FDR data.
These copied traces have used the highest resolutions available and also have a Smoothed Normal Acceleration curve added to give an indication where the +/- 'g' forces were. From the commencement at 02:10:51.4 of the Stall Warning, thin dotted lines showing the 'smoothed' traces for both the AoA and Pitch Attitude angles are included.
CLMAX occurred at 02:10:56.5, and the 'g' break within a further second. Some post stall pitching oscillations matched by the AoA values took place for a few more seconds before the AoA rapidly moved toward 30 degrees and the FPA moved into negative territory.
Back earlier at the AP and ATHR disconnect(s), the traces are rather 'lumpy' - an artifact of the turbulence occurring as the aircraft commenced the initial climb.
The Initial Stall Analysis is here, and HN39's description of how the initial data was constructed is in AF447 - Thread No.5 - post #70
These copied traces have used the highest resolutions available and also have a Smoothed Normal Acceleration curve added to give an indication where the +/- 'g' forces were. From the commencement at 02:10:51.4 of the Stall Warning, thin dotted lines showing the 'smoothed' traces for both the AoA and Pitch Attitude angles are included.
CLMAX occurred at 02:10:56.5, and the 'g' break within a further second. Some post stall pitching oscillations matched by the AoA values took place for a few more seconds before the AoA rapidly moved toward 30 degrees and the FPA moved into negative territory.
Back earlier at the AP and ATHR disconnect(s), the traces are rather 'lumpy' - an artifact of the turbulence occurring as the aircraft commenced the initial climb.
The Initial Stall Analysis is here, and HN39's description of how the initial data was constructed is in AF447 - Thread No.5 - post #70
Last edited by mm43; 5th Sep 2011 at 19:34. Reason: Revised graphic & stall description
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Hi DozyWannabe,
I've never heard of that.
PF / PNF can swap roles at any time - usually one crew member is allocated the pleasure of doing the take off and landing for his records. Unusually with this crew was their relative seat positions. The more experienced senior Co-pilot was not in his natural seat (Co-pilots occupy the RHS), and may have felt some anxiety about taking control and using his non natural hand on the side stick.
Remember that the rules state that the non-relief pilot is not to take control without the Captain's say-so under most conditions.
PF / PNF can swap roles at any time - usually one crew member is allocated the pleasure of doing the take off and landing for his records. Unusually with this crew was their relative seat positions. The more experienced senior Co-pilot was not in his natural seat (Co-pilots occupy the RHS), and may have felt some anxiety about taking control and using his non natural hand on the side stick.
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@rudderrudderrat
Read the 3rd interim report. This was a very specific procedure within AF for a long-haul flight whereby the crew consists of a Captain, F/O and a relief pilot who is not a Captain. The Captain is supposed to brief the rest of the crew as to roles and responsibilities (including parameters for taking control) prior to the flight or at handover. The record suggests that this was not done.
I honestly don't think you're going to find any technical reason for this - handedness is not an issue, and as it seems relief pilots can sit in either seat it's not like F/Os get no practice with it on that side. I know some people want it to be about the sidestick, autotrim and lack of feedback but the odds are stacking up against it.
Read the 3rd interim report. This was a very specific procedure within AF for a long-haul flight whereby the crew consists of a Captain, F/O and a relief pilot who is not a Captain. The Captain is supposed to brief the rest of the crew as to roles and responsibilities (including parameters for taking control) prior to the flight or at handover. The record suggests that this was not done.
I honestly don't think you're going to find any technical reason for this - handedness is not an issue, and as it seems relief pilots can sit in either seat it's not like F/Os get no practice with it on that side. I know some people want it to be about the sidestick, autotrim and lack of feedback but the odds are stacking up against it.
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Good Morning DW,
All the hand flying practice will have been done from the co-pilot's natural position (RHS). During cruise relief, when seated in the LHS - all inputs will have done through the auto-pilot.
Occasionally, in the simulator the co-pilot will get an opportunity to hand fly from the LHS - and from what I've observed, some find it much more difficult. Try playing tennis with your non natural hand and let me know how you get on.
The side stick is a perfect device for controlling the aircraft in Normal Law (nudge to attitude and let go), but is not ideal for controlling Roll in Alternate Law (it's too sensitive and needs constant pressure until the aircraft is perfectly trimmed).
The conventional control column is able to accept both hands and is more natural than the side stick from either seat.
Edit. If there was so little difference between the handedness of the side sticks, seat positions etc., why do you think it is mandatory for Training Captains (who can occupy either seat) to additionally perform EFTO & GA procedures from the co-pilot seat in the simulator? If there was so little difference - we wouldn't bother.
...handedness is not an issue, and as it seems relief pilots can sit in either seat it's not like F/Os get no practice with it on that side.
Occasionally, in the simulator the co-pilot will get an opportunity to hand fly from the LHS - and from what I've observed, some find it much more difficult. Try playing tennis with your non natural hand and let me know how you get on.
The side stick is a perfect device for controlling the aircraft in Normal Law (nudge to attitude and let go), but is not ideal for controlling Roll in Alternate Law (it's too sensitive and needs constant pressure until the aircraft is perfectly trimmed).
The conventional control column is able to accept both hands and is more natural than the side stick from either seat.
Edit. If there was so little difference between the handedness of the side sticks, seat positions etc., why do you think it is mandatory for Training Captains (who can occupy either seat) to additionally perform EFTO & GA procedures from the co-pilot seat in the simulator? If there was so little difference - we wouldn't bother.
Last edited by rudderrudderrat; 30th Aug 2011 at 08:38.
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So what you mean is "I prefer a conventional control column, so I'm going to keep blaming the sidestick design wherever possible".
That's fine, we're all entitled to our opinions - just don't pretend you're being objective when you've already decided you're going to fit this accident around your personal bugbears with the system.
That's fine, we're all entitled to our opinions - just don't pretend you're being objective when you've already decided you're going to fit this accident around your personal bugbears with the system.
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Hi DozyWannabe,
under certain circumstances like direct law - yes. Otherwise conventional aircraft would have adopted side stick controls for weight saving and reduced engineering complexity years ago.
This AC series is designed around Normal Law - and the side stick works brilliantly well when used in this law. If the autopilot had simply disengaged with Normal Law still active - PF would not have had any difficulty keeping it straight and level.
I don't have any personal bugbears - I'm trying to explain why I think the PF had so much difficulty in hand flying in ALT LAW at high altitude.
So what you mean is "I prefer a conventional control column"
This AC series is designed around Normal Law - and the side stick works brilliantly well when used in this law. If the autopilot had simply disengaged with Normal Law still active - PF would not have had any difficulty keeping it straight and level.
I don't have any personal bugbears - I'm trying to explain why I think the PF had so much difficulty in hand flying in ALT LAW at high altitude.
mm43
The following is a combination of FDR traces posted in a format used to convey the data that HazelNuts39 had originally constructed from the BEA's initial report on the FDR data.
The following is a combination of FDR traces posted in a format used to convey the data that HazelNuts39 had originally constructed from the BEA's initial report on the FDR data.
Pay attention to the smoothed normal acceleration curve:
02:10:05 - 02:10:12, 7 seconds, load increase from 1,0 g to 1.4 g
02:10:12 - 02:10:40, 28 seconds, load decrease from 1.4 g to 0.8 g
02:10:40 - 02:10:55, 15 seconds, load increase from 0,8 g to 1.1 g
02:10:55 - 02:12:00, 65 seconds, load decrease from 1,1 g to 0.9 g
What the crew really felt despite their SS actions, was the initial overshooting in g in the first 7 seconds, then the correction phase for 28 seconds, then a increase again to 1,1 g in 15 seconds, followed by going below 1 g in the following 65 seconds.
Caught of guard by speed loss and AP/ATHR dropout combined with lack of training and stress might have increases the danger to follow the feel in the pants instead stick to the instruments, like we climbed too much, but now it feels like leveling.... even descending when below 1 g and do not disturb the cabin too much.....
Loose straps with impaired seating position (we do not know, wether the seatbelts of PF separated due to impact or if they had been donned inproperly). might have influenced the resistance to unload further. Best seen here also, that the erratic stick inputs of PF (after initial pitch) does not influence the big picture concerning g-loading that much. When we talk about too much backstick pressure after the initial pullup and compare it to the g loading, then the resulting aircraft response does not represent the SS inputs that clearly.
Talking about traces, the post from lampaeso is an interesting compilation of traces with cockpit communication, thanks very much for that work.
What struck me most is the fact, that the pitch came down below the horizon in several timeframes, and mostly in combination not to SS pitch ND inputs, but to big bank angles to the right in combination with full oposite SS input and even SS full NU inputs.
02:11:55, 25° RH bank, SS full left, SS full NU, pitch -10°
02:12:10, 20° RH bank, SS full left, SS full NU, pitch -10°
02:12:50, 40° RH bank, SS full left, SS half NU, pitch - 5°
02:13:00, 40° RH bank, SS full left, SS half NU, pitch -5°
02:13:55, 30° RH bank, SS full left, SS full NU, pitch -5° (double input)
Watch also the stall warning and VVI during these occasions as well as the CVR.
We have been critical of PF for stalling the thing, but as RF4 has pointed out he was trying for a couple minutes to stay right side up with the a/c seemingly not responding to left stick.
A couple weeks ago I got a ride in the back seat of a Romanian Lark glider with a long thin wing. Thermaling the beast past 30° bank found me with the stick in the opposite rear corner.
Had to unload a bit to get some more aileron authority. Many gliders lose aileron authority before they stall from a steep bank in a thermal and I am at a loss that an experienced glider pilot would not have been familiar with this.
As mentioned many times before the transition from an apparent overspeed problem to a stall problem was not recognised.
A couple weeks ago I got a ride in the back seat of a Romanian Lark glider with a long thin wing. Thermaling the beast past 30° bank found me with the stick in the opposite rear corner.
Had to unload a bit to get some more aileron authority. Many gliders lose aileron authority before they stall from a steep bank in a thermal and I am at a loss that an experienced glider pilot would not have been familiar with this.
As mentioned many times before the transition from an apparent overspeed problem to a stall problem was not recognised.
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I know some people want it to be about the sidestick, autotrim and lack of feedback but the odds are stacking up against it.
Few, if any, are denying that PF was way below par from manual takeover to end of story... with general crew shortcomings becoming apparent.
But really, you have to stop this black and white routine, any engineer will tell you very few solutions, much in nature and certainly not accidents are so black & white
All those 3 things did play some part (notwithstanding similar accidents in the past happening without them - that is a false negative), I believe.
To start slamming a control column about like that (just think of the equivalent), would definitely have woken up the Captain upon entry, even if PNF had still stayed subdued (this accident will no doubt turn into a study case for at least pilot shock & stress behaviour as much as CRM itself).
Indeed, AF should be consulting the RAF crew selection centre (as was) about some help?
There is almost no argument that Captain would not have responded to visually seeing a full aft stick in PFs hands - end of.
No doubt he would then have looked straight at the Trimwheel, and PFD
My guess Captain had no idea that PF (had been and) was still obsessed with an UP/ DOWN mentality, and at night, was totally removed from any sense of wind over wings and AoA (something even crude Q-pot feedback could provide)
I think PF having flown sailplanes is very much a red herring.. he was no Sully.
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