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Air France Off the Hook on AF447

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  • #16
    Originally posted by Evan View Post
    But, in beating this crash to death, we've stumbled upon the realization that no appropriate 'memory checklist QRH acronym' thing exists for this scenario.
    Yes, we have established that a 'memorychecklistqrhacronymthing' does not exist.

    However, there is a cute mnemonic called "Aviate, Navigate Communicate" that I was taught in 172 school, and which I believe is (or has been) sometimes uttered by ATL, Bobby, VNav, RCL, Snyder Snapshots, Eric, Gabriel, 3BS, JetCaptain, Guammanite, Saint Donald, MikeD, ITS and many others.

    It works in almost all types of aircraft for a very wide set of circumstances.

    Again we diverge- I think it is extremely adequate- perhaps even preferable.

    BUT

    Because it is not type specific, not black and white (Edit- I see you used red and green to disguise your black and white thinking...cute) and devoid of acronyms, you find it woefully inadequate.

    We (most of us, that is) maintain it would have been extremely likely to have prevented the crash.

    ...C'est la vie.

    AND, as long as we are speaking French: Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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    • #17
      Originally posted by Gabriel View Post
      I could think 250 other ways to improvise that are more compatible with basic airmanship, common sense, and survival.
      Can you provide a list?

      Originally posted by Gabriel View Post
      Wheee!!!! Im-prov-time, im-prove-time!!! I know, I know! Let's pull a 1.5 G 7000 fpm 2500 ft climb and when the stall warning starts shouting "stall stall" let's "pull up all the time" all the way to the ocean!!!! In a minefield of misleading indications, including 3 attitude indicators, 3 altimeters, 2 vertical speed indicators, a stall warning and a bio-G detector that were all sending consistent messages.
      It's funny... this thread got me to thinking about something and it is this: in an airliner, is it *ever* appropriate to hold the column/stick at its rearward stop for more than 5 or10 seconds? Ever? Ever? I mean when flying of course, maybe there's some reason to do it on the ground.

      The only time I can think of where that would make sense is if you have a trim problem (insert reference to MCAS issue here)... which of course would not happen on an A330 as it doesn't have a "trim system" per se.
      Be alert! America needs more lerts.

      Eric Law

      Comment


      • #18
        Originally posted by elaw View Post
        But let me ask this: we have tons of facts relating to what the pilots did, and what the result was. Are there any facts available that show conclusively *why* they did what they did? I'm pretty sure there aren't, so speculation is all we're left with. And that's what I did... speculate.
        Is it that hard, really?
        1. He was used to pull up (precisely the same way?), and the plane was always doing the right thing (arguably, but it wasn't stalling at least). Wonder what FDR showed for his previous flights.
        2. The plane started to fall from the sky and none of them recognized why. Perhaps they didn't know what a stall really is? There is, or at least (hopefully) was, a common misconception involving airspeed and maybe attitude.

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        • #19
          Originally posted by Evan View Post
          Consistent perhaps. But misleading.
          Yes... the altimeters did go down a bit when the almost-totally-static-pressure ports lost the fine-tuning correction of the total-pressure ports (i.e. the difference between the almost-totally and totally). But overall? All 3 altimeters showed clear climb from A to B, where the accuracy error in A and B was so much smaller than the distance between A and B, and the 2 vertical speed indicators showed a climb speed that pretty much matched the speed at which the numbers in the altimeter were passing by, all while the attitude indicator showed a pitch that was more consistent with a take-off than a standard cruise climb but was however very consistent with this non-standard skyrocketing climb.

          I'd say that, overall, the 3 AI, 3 ALT and 2 VSI and 2 bio-G were not only consistent among themselves, but pretty much consistent with reality too, and hence pretty much NOT misleading.

          But that's not what happened.
          It's close to what happened.

          Ok, who am I fooling? This discussion has zero chance to lead somewhere.

          --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
          --- Defend what you say with arguments, not by imposing your credentials ---

          Comment


          • #20
            Originally posted by Gabriel View Post
            Yes... the altimeters did go down a bit when the almost-totally-static-pressure ports lost the fine-tuning correction of the total-pressure ports (i.e. the difference between the almost-totally and totally). But overall? All 3 altimeters showed clear climb from A to B, where the accuracy error in A and B was so much smaller than the distance between A and B, and the 2 vertical speed indicators showed a climb speed that pretty much matched the speed at which the numbers in the altimeter were passing by, all while the attitude indicator showed a pitch that was more consistent with a take-off than a standard cruise climb but was however very consistent with this non-standard skyrocketing climb.
            Yes, but they were misleading at 2h 10min 05. When the idea to pull up first came to mind.

            It's close to what happened.

            Ok, who am I fooling? This discussion has zero chance to lead somewhere.
            Not if you refuse to look carefully at the FDR and see how very far from 'pulling up the whole time' it really was. Then the discussion can't be had.

            Comment


            • #21
              Originally posted by Evan View Post
              Yes, but they were misleading at 2h 10min 05. When the idea to pull up first came to mind.



              Not if you refuse to look carefully at the FDR and see how very far from 'pulling up the whole time' it really was. Then the discussion can't be had.
              Evan, he was pulling up all the time on average, and I am talking about short-term moving average, not just overall...

              Now, ok, in a "traditional" plane (including Boeing FBW), you pull say 1/4 back and the plane quickly stabilizes at the new AoA and eventually it will reach its new speed of equilibrium for that AoA (after the phugoid oscillations if not dampened by the pilot or the FBW).

              Now, in an Airbus in normal or alternate law, pull back 1/4 and it means keeping more than 1G, there is no equilibrium to be reached ever with the control pulled anything back. Even in normal law when the speed goes down it transitions from G-on-stick to pitch-rate-on-stick so in both cases it would keep pitching up indefinitely, if it's not by protections (most of them lost in alternate law) or physical limitations (like stalling).

              Now, the pilot when hand-flying (the same than a driver when driving) is part of a closed-loop control system. You just don't put the elevator at 1/4 back and leave it there. You have a performance goal in mind (remember that conversation???) and compare the actual performance with the desired performance and make the necessary adjustments in the control. That's why you see the pilots moving the yoke or stick almost all the time in an approach to landing. Now, what was the performance goal that this pilot had in mind again???? Because the way that he was beating mayonnaise with the stick has no rational correlation with him trying to achieve any specific performance. The point is not what was the instantaneous position of the stick at each second. The point is that by doing what he did with the stick he actively performed an unsustainable skyrocketing climb (and he might have lost the speeds but the other 8 instruments were consistent with this crazy climb) and, when a warning that is actually an APPROACH to stall warning sounded, he pulled up again sending the pitch up again and the AoA with it and actively stalling the plane, and kept pulling up on average whcih made the AoA increase to 40 degrees, ignoring the fact that the pitch was showing 10 deg up, the vertical speed was 10K fpm down, the altimeters were unwinding like crazy, and did I mention the stall warning that since the first "stall" announcement at the top of the climb was sounding uninterruptedly for 30 seconds?

              Say that you drive the car in a road that is straight but a bit uneven and there are gusting crosswinds. You will need to make permanent adjustments to keep the car on the desired lane, and you will compare the actual track of the car with the desired track (i.e. keep the lane) to make continuous adjustments in the steering wheel. If you start to move the steering wheel all over the place but with a clear average to the left, you will very soon depart the road and then declare "but I was NOT turning left all the time".

              Even the pilot admitted that "I was pulling up all the time". While if you read the fine print that is not exactly what he did at each instant, it is clear that that was his main focus and what he did on average (again, even short-term moving average).

              --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
              --- Defend what you say with arguments, not by imposing your credentials ---

              Comment


              • #22
                Originally posted by Gabriel View Post
                Evan, he was pulling up all the time on average, and I am talking about short-term moving average, not just overall...

                Now, ok, in a "traditional" plane (including Boeing FBW), you pull say 1/4 back and the plane quickly stabilizes at the new AoA and eventually it will reach its new speed of equilibrium for that AoA (after the phugoid oscillations if not dampened by the pilot or the FBW).

                Now, in an Airbus in normal or alternate law, pull back 1/4 and it means keeping more than 1G, there is no equilibrium to be reached ever with the control pulled anything back. Even in normal law when the speed goes down it transitions from G-on-stick to pitch-rate-on-stick so in both cases it would keep pitching up indefinitely, if it's not by protections (most of them lost in alternate law) or physical limitations (like stalling).

                Now, the pilot when hand-flying (the same than a driver when driving) is part of a closed-loop control system. You just don't put the elevator at 1/4 back and leave it there. You have a performance goal in mind (remember that conversation???) and compare the actual performance with the desired performance and make the necessary adjustments in the control. That's why you see the pilots moving the yoke or stick almost all the time in an approach to landing. Now, what was the performance goal that this pilot had in mind again???? Because the way that he was beating mayonnaise with the stick has no rational correlation with him trying to achieve any specific performance. The point is not what was the instantaneous position of the stick at each second. The point is that by doing what he did with the stick he actively performed an unsustainable skyrocketing climb (and he might have lost the speeds but the other 8 instruments were consistent with this crazy climb) and, when a warning that is actually an APPROACH to stall warning sounded, he pulled up again sending the pitch up again and the AoA with it and actively stalling the plane, and kept pulling up on average whcih made the AoA increase to 40 degrees, ignoring the fact that the pitch was showing 10 deg up, the vertical speed was 10K fpm down, the altimeters were unwinding like crazy, and did I mention the stall warning that since the first "stall" announcement at the top of the climb was sounding uninterruptedly for 30 seconds?

                Say that you drive the car in a road that is straight but a bit uneven and there are gusting crosswinds. You will need to make permanent adjustments to keep the car on the desired lane, and you will compare the actual track of the car with the desired track (i.e. keep the lane) to make continuous adjustments in the steering wheel. If you start to move the steering wheel all over the place but with a clear average to the left, you will very soon depart the road and then declare "but I was NOT turning left all the time".

                Even the pilot admitted that "I was pulling up all the time". While if you read the fine print that is not exactly what he did at each instant, it is clear that that was his main focus and what he did on average (again, even short-term moving average).
                Gabriel, I concede that the aircraft was pitching up the entire time. I believe his intention might have been initially to regain lost altitude and arrest sink rate and then to climb to FL37, and his performance goal was to expedite that climb as much as possible. I am only concerned with the first 45 seconds or so of the event, because, if a crew can't stabilize and establish clear situational awareness by then, we should expect situational awareness to entirely degrade, mental performance to entirely degrade and, after that, anything can happen. In short, it can never go that far.

                So, I'm asking you to do two things that you thus far refuse to do: 1) concentrate on the first 45 secs (the first two pages on the FDR) and 2) look at it carefully. What do you see?

                You see variable pitch inputs (load factor commands) that include forward stick inputs. He is not 'pulling up the entire time'. He seems to be attempting to maintain an expedited but sustainable climb angle (with an unpracticed and panicked hand). There are initially two stall warnings, one at 2h 10min 10 and another 3 secs later. The warnings then cease for another 45 secs or so (in other words, for the rest of the time period we are concerned with). Immediately following these warnings, the thrust is removed from thrust lock and placed in full CL (N1 goes from around 80% to around 100%), which, along with the abatement of the stall warnings, may have led the pilot to think the climb was sustainable. He wouldn't have been wrong about that. The initial climb was sustainable. The aircraft did not stall. Then, following the instruction of the senior F/O, the pilot enters a period of decreased pitch attitude (from 12deg down to 6deg) and decreased vertical speed (from 7000fpm down to 1100fpm). This trend then continues for about 25 secs (to the end of the period I am concerned with).

                Yes, he is still pitching up the entire time, but clearly his intention is not to climb the entire time or to continuously increase the angle-of-attack. Your interpretation of a 'crazy, continuous pull up into a stall' does not synch with reality. What happens after this crucial time interval does appear crazy (I suspect he began following the FD's which had suddenly reappeared since a procedure wasn't there to assure they were switched off), but, as I've said, if it ever gets to that point we have to consider the game lost anyway.

                So, if you have any interest in understanding what might have driven his initial mistakes (and thus find ways to create defenses against them), look more closely at the FDR. If you want to just call it 'crazy' and describe his actions in absolute terms, then don't bother.

                Comment


                • #23
                  Originally posted by elaw View Post
                  Can you provide a list?


                  It's funny... this thread got me to thinking about something and it is this: in an airliner, is it *ever* appropriate to hold the column/stick at its rearward stop for more than 5 or10 seconds? Ever? Ever? I mean when flying of course, maybe there's some reason to do it on the ground.
                  In a CFIT escape situation, the memory item calls for the stick to be held full aft until such time as we're out of CFIT danger. The caveat being that we're talking about an envelope-protected aircraft.

                  Comment


                  • #24
                    Originally posted by Evan
                    concentrate on the first 45 secs
                    Ok in the first 45 seconds...he pulled up moderately aggressively in a manner consistent with causing a stall, when "the correct procedure" was to maintain a reasonably stable attitude. This is absolutely one of the wrongest things you can do and goes against almost all fundamentals.

                    Then after 45 seconds, he pulled up in a different aggressive manner consistent with causing a stall. This, also, is absolutely one of the wrongest things you can do and goes against almost all fundamentals.

                    I get your hair-splitting on variations within a relentless pull up, and your attempt to discern the coveted "thought process"...nevertheless it is STILL totally whacko-wrong regardless of your timeslice, and probably irrelevant that they had different thoughts at different times....what they did was hellaciously wrong most of the time, and I am just an uber-ass-hat-unqualified-parlour-talker and pretty sure I would have done better.
                    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                    Comment


                    • #25
                      My simplistic take on this accident is that the confusion and stress caused by a failure in some systems and the move to a joystick led to a loss of an adherence to first principles. I asked quite recently if the artificial horizon worked independently and was assured that it does. Similarly, in this case the altimeter was delivering reliable data. The failure by three highly trained pilots to assess and interpret the information from these two sources and to act accordingly is difficult to understand. To return to the joystick.This is tucked away and gives little in the way of visual clues as to any egregious mishandling. I would suggest that if the three pilots had seen a yoke being pulled back against the stops, a very large mutual thought bubble containing the word "stall" might have appeared.

                      Comment


                      • #26
                        Originally posted by pegasus View Post
                        My simplistic take on this accident is that the confusion and stress caused by a failure in some systems and the move to a joystick led to a loss of an adherence to first principles. I asked quite recently if the artificial horizon worked independently and was assured that it does. Similarly, in this case the altimeter was delivering reliable data. The failure by three highly trained pilots to assess and interpret the information from these two sources and to act accordingly is difficult to understand. To return to the joystick.This is tucked away and gives little in the way of visual clues as to any egregious mishandling. I would suggest that if the three pilots had seen a yoke being pulled back against the stops, a very large mutual thought bubble containing the word "stall" might have appeared.
                        1) The altimeters are dependent on airspeed data and are thus compromised by a pitot failure. The error is on the order of approximately 300ft. The vertical speed indicator is also erronous. The only 'good' basic flight instrument on the PFD is the artificial horizon. That is why the procedure must stress the need to fly by pitch, not by any of the other instruments.

                        2) During the critical first minute, the stick was never pulled back to the stop. That is a myth that perpetuates on internet forums, including this one. This only occurred after the plane was fully stalled. Also, the stick inputs were very active, ranging from backward (nose up) to forward (nose down). Watching the stick movements would not have told the story. Watching the artificial horizon would have however.

                        Comment


                        • #27
                          Originally posted by Evan View Post
                          1) The altimeters are dependent on airspeed data and are thus compromised by a pitot failure. The error is on the order of approximately 300ft. The vertical speed indicator is also erronous. The only 'good' basic flight instrument on the PFD is the artificial horizon. That is why the procedure must stress the need to fly by pitch, not by any of the other instruments.
                          Do you mean that the 3 altimeters and 2 vertical speed indicators did not capture the essence of the zoom climb with the altimeters winding up quickly and the vertical speed indicator showing thousands of feet per minutes up? (besides the artificial horizon showing an attitude that is unsustainable at those altitudes).

                          --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                          --- Defend what you say with arguments, not by imposing your credentials ---

                          Comment


                          • #28
                            First 20 seconds starting at AP disconnect (red vertical line).

                            Click image for larger version

Name:	AF447 FRD.JPG
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                            --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                            --- Defend what you say with arguments, not by imposing your credentials ---

                            Comment


                            • #29
                              It's forums. The answers you get don't relate to the point that is being made. In basic airmanship, if you saw the pilot sawing back and forth with the yoke and the altimeter was unwinding in a frightening way, the artificial horizon would be the first point of reference to restore a safe attitude. The absence of this visceral response poses the question - are they flying or trying to manage a system. Or has the balance between the two been lost?

                              Comment


                              • #30
                                Originally posted by Gabriel View Post
                                Do you mean that the 3 altimeters and 2 vertical speed indicators did not capture the essence of the zoom climb with the altimeters winding up quickly and the vertical speed indicator showing thousands of feet per minutes up? (besides the artificial horizon showing an attitude that is unsustainable at those altitudes).
                                No. I mean they are unreliable and will give misleading indications, specifically, that you are now in a descent and must command some load factor to regain your previous flight level. This will result in increased pitch, a departure from level flight and a speed reduction. This is where it begins to go wrong.

                                What you want is to maintain your current flight path with as little deviation as possible. That requires you to focus on the artificial horizon, not the altimeter, not the VSI.

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