Announcement

Collapse
No announcement yet.

Pitot Tube Failure

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #91
    Originally posted by Gabriel View Post
    I said it before: In aviation it is almost forbidden to say "it will never happen to me".
    And why do you think that is? Because it's almost certainly naive hubris?

    You handled a (senseless) stall warning situation in the 747 sim. You had no prior concern to ascribe it to (no food for confimation bias). It was in visual flight conditions. You told us that you focused your attention on the visual situation out the window and the tactile and aural stall warnings, and flew it by concentrating (tunnelling) on these aspects.

    AF447 happened in turbulent IMC with no visible horizon and no tactile feedback. The PF most likely focused his attention on instrumentation (which was erroneous and misleading) and bewildering ECAM (the PNF was not communicating ECAM clearly to him). The PF was tasked with stabilizing roll turbulence as well as pitch (with some vertical acceleration from turbulence). The PF had a very strong prior concern about weather and a strong desire to climb above it, and was probably deeply affected by confimation bias at that moment. Stall AoA was about 4.5°. This situation cannot be learned in a Cassna (or a Tomahawk).

    I've tried to point out to you and others here that this wasn't primarily a case of bad basic airmanship. It just falls on deaf ears.
    I've tried to point out to you and others here that only a disciplined adherence to procedure can defend against the deceptions and human factors that arise in a situation like this. That just seems to bounce off you.

    Fortunately, pilots do not administer aviation safety directives. The BEA and the industry regulators are not susceptible to pilot-induced-hubris, and they have made changes. The AF-447 pilots had received their only stall (avoidance, not recovery) training during type-certification year earlier, and it focused on low-altitude, high-AoA situations. None of them had high-altitude upset aircraft handling and upset recovery training. Human factors were largely ignored in the training they did have.
    5 - CHANGES MADE FOLLOWING THE ACCIDENT
    5.1 Air France
    5.1.3 Crew training
    Flight simulator training
    Additional unreliable airspeed session:
    • Summer 2009 (A320, A330/A340).
    • Session booklet and briefing: technical reminders, human factors and Threat and Error Management (TEM) aspects.
    • Revision of the emergency manoeuvre, on take-off and in cruise phase.
    • High altitude flight in alternate law.
    • Approach to stall with triggering of STALL warning.
    • Landing without airspeed indications.
    • Related briefings (all flight crew):
      --Weather radar
      --Ice crystals.
    • Alternate Training & Qualification Programme (ATQP) (preliminary version)
      operational on Airbus A320 since March 2012.

    Note: These elements were incorporated into the type ratings

    This will not prevent another AF447, however, if pilots continue to resist the lessons learned from it, particularly the humility of being susceptible to deceptive human factors and the importance of following procedure for this reason alone.

    Now you can go back to talking about what stellar airman you are on cable-driven low altitude aircraft at 120kts.

    Comment


    • #92
      Originally posted by Evan View Post
      And why do you think that is? Because it's almost certainly naive hubris?
      Yes, most of the time. You will never hear me say "I will never run out of gas" or "I will never be caught VFR in IMC" or "I will never lose situational awareness and CFIT". Not even "I will never (unintentionally) stall a plane".
      I surely sound pedantic and I may be wrong, but I honestly think that I would have never crashed AF447 (or Colgan fatigue and all, on Pinnacle, or Austral, or Spanair) in the way they did.

      You handled a (senseless) stall warning situation in the 747 sim. You had no prior concern to ascribe it to (no food for confimation bias). It was in visual flight conditions. You told us that you focused your attention on the visual situation out the window and the tactile and aural stall warnings, and flew it by concentrating (tunnelling) on these aspects.
      Everything is situational. My main focus was the stickshaker, reducing the AoA as little as possible to silence it which initially produced a descent so I pulled up again. I was taking off, "safe conduct of the flight" was in question and, while never told me that and I had not read the stall procedure for the take-off stall in the 747-200, I knew that I had to find the balance to ensure not stalling while at the same time, if possible, not descending. Yes, the view out out of the window was a big part of that, to judge if the plane was going up or down or if there were obstacles, but at the same time it was the ONLY thing that mattered that I had to look with my eyes. Call it tunnel vision if you want, but the airspeed was meaningless (I had rotated at the prescribed speed and was above V2 by then, so this should not have been happening if it was for the speed, another pilot more focused on procedures and numbers may have been more focused on keeping V2 which, again, was meaningless), attitude I could tell from the real horizon, FD was meaningless (it most likely was telling me to pitch up), altimeter is not sensitive enough when you are skimming a few feet over the runway, and for the stickshaker I didn't need my eyes. Focusing in what matters is not tunneling. And did I say that it happened during the lift-off? Had I been at altitude I am pretty confident that I would have lowered the nose much more liberally and looked at things like the attitude and speed. Context.

      AF447 happened in turbulent IMC with no visible horizon and no tactile feedback. The PF most likely focused his attention on instrumentation (which was erroneous and misleading) and bewildering ECAM (the PNF was not communicating ECAM clearly to him). The PF was tasked with stabilizing roll turbulence as well as pitch (with some vertical acceleration from turbulence). The PF had a very strong prior concern about weather and a strong desire to climb above it, and was probably deeply affected by confimation bias at that moment. Stall AoA was about 4.5°. This situation cannot be learned in a Cassna (or a Tomahawk).
      Really? Do you think that doing basically NOTHING like I initially did in the Tomahawk would not have worked initially?

      I've tried to point out to you and others here that this wasn't primarily a case of bad basic airmanship. It just falls on deaf ears.
      I've tried to point out to you and others here that only a disciplined adherence to procedure can defend against the deceptions and human factors that arise in a situation like this. That just seems to bounce off you.
      Ok, a couple of comments here.
      1- By all means DO FOLLOW THE PROCEDURES. I said that a gazillion times already.
      2- There is a big range between NOT FOLLOWING THE PROCEDURES and pull up a 1.5, 7000 fpm, 2500 feet climb from FL350 ISA+20 and, once leveled of at the top of the climb, when the speed (that is already working again) goes down after your unsustainable climb and the stall warning comes out, pull up hard back and keep "pulling back all the time" until you hit the ocean. The stall warning was sounding (and I mean a cricket sound and an aural STALL STALL) uninterruptedly for 30 seconds (then intermittently) with 3 good (by then) airspeed indicators showing a too low speed but more importantly 3 good attitude indicators showing more than 10 degrees ANU coupled with 3 good altimeters unwinding at a ridiculous speed and 2 good vertical speed indicators showing many thousands of feet per minutes down.
      There are other ways of not following the procedure that, while not advisable, would have had a much different outcome. THIS way was totally ineffective but also totally unnatural for a pilot. Why did it happen? I don't know. You claim that strict adherence to procedures would have prevented it. But that is a tautology: Yes, not crashing would have prevented the crash. If the pilot would have tried to do something remotely reasonable from a cowboy pilot point of view (like trying a reasonable climb) I would agree. But the pilot was pulling up hard immediately after the AP disconnected. Why? Startle? Panic? How wold this startle or panic that prevented the pilot to keep a reasonable climb (if that was what he was trying to do, according to your version, which I very much doubt) would have allowed him to invoke the procedures and keep a steady 5 deg and CLB? (which was the WRONG thing to do anyway, which bring us to...)
      3- Ok. I got it and I've already said a million times that I agree: Strict adherence to procedure. Which procedure? Because the last time I checked the procedure applicable to that situation was at the time of the AF accident, and still is today, for a high altitude cruise and already leveled-off flight, do NOTHING initially and then follow the prescribed technique to fly with no airspeed using the pitch and power table in the QRH as a ballpark reference. How is that so different from what you would do in a Tomahawk (except that you don''t have the QRH table)? Or from what I, 3we and, most importantly, ATL are saying? (acknowledged, he should have turned off the FD)

      This will not prevent another AF447, however, if pilots continue to resist the lessons learned from it, particularly the humility of being susceptible to deceptive human factors and the importance of following procedure for this reason alone.
      Do you know any pilot in that category? Here it goes again: DO FOLLOW THE PROCEDURES.

      Now you can go back to talking about what stellar airman you are on cable-driven low altitude aircraft at 120kts.
      I am not a stellar pilot at all. I am not even a very good one. In the same thread where I described how well I managed the stall in the 747 sim I also described how crappy I was trying to control airspeed and altitude and how many miles I was flying behind the airplane. Sorry if I sound pedantic, but I feel that I am particularly good at AoA awareness (compared to other thing at which I am not so god, NOT compared to other pilots).

      If you are driving a car and the street makes a left turn but instead you turn right and end up in a stonewall, then "not following the left turn procedure" is not a good enough explanation.
      Both 3we and I said it: We feel confident that we wold not have crashed AF 447 IN THAT WAY (but possibly yes in other ways, I would likely had lost control in IMC).

      This pilot didn't just fail to follow the procedure. What he did made no sense whatsoever no matter what was his goal or what he attempted to do, unless he attempted to stall and crash, which I am sure it was not the case.

      --- 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


      • #93
        Originally posted by Gabriel View Post
        Everything is situational. My main focus was the stickshaker, reducing the AoA as little as possible to silence it which initially produced a descent so I pulled up again. I was taking off, "safe conduct of the flight" was in question and, while never told me that and I had not read the stall procedure for the take-off stall in the 747-200, I knew that I had to find the balance to ensure not stalling while at the same time, if possible, not descending. Yes, the view out out of the window was a big part of that, to judge if the plane was going up or down or if there were obstacles, but at the same time it was the ONLY thing that mattered that I had to look with my eyes. Call it tunnel vision if you want, but the airspeed was meaningless (I had rotated at the prescribed speed and was above V2 by then, so this should not have been happening if it was for the speed, another pilot more focused on procedures and numbers may have been more focused on keeping V2 which, again, was meaningless), attitude I could tell from the real horizon, FD was meaningless (it most likely was telling me to pitch up), altimeter is not sensitive enough when you are skimming a few feet over the runway, and for the stickshaker I didn't need my eyes. Focusing in what matters is not tunneling. And did I say that it happened during the lift-off? Had I been at altitude I am pretty confident that I would have lowered the nose much more liberally and looked at things like the attitude and speed. Context.
        You missed my point. i"m not criticizing your actions in the sim (I think you aced it). I'm pointing out that there was nothing deceiving you there. There was no 'food' for confirmation bias. I'm pointing out the things you are not considering in comparing it to AF447. I listed them there, so I'm not going to list them again, but they affect perception, situational awareness, human judgment and human performance. You can't compare, or even understand, that situation without considering these things. Context.

        Really? Do you think that doing basically NOTHING like I initially did in the Tomahawk would not have worked initially?
        Doing nothing would have worked, yes. But improvising does not mean 'doing nothing', and, as I pointed out, the instruments were urging the pilot to do something wrong. If he had a procedure to follow involving ONLY pitch and power (along with the obvious roll control), he could have essentially done nothing, or at least done nothing dangerous. I think this point is quite clear but you still don't seem to acknowledge it. And, yes, I'm now aware that there isn't a specific memorized procedure for stabilizing UAS at cruise, which troubles me. As I said to ATL, I would rest easier if the procedure simply called for '95% N1 and fly the first hashmark' or even 'use typical pitch and power for the current phase of flight' but the procedure must prevent the pilot from doing anything else before getting clear situational awareness and CRM underway (including running through the QRH procedure). And it must remove the automation and the flight directors. That's what I'm saying.

        Pierre Bonin probably noticed the declining altitude and the negative vertical speed, and he probably didn't want to descend into the CB monster that was effing up his airplane and he probably wanted to climb higher above it, but the instruments were lying to him. Did he fly it by pitch or by altimeter/VSI? Pitch would be safe. Instruments would be a potential mess. Flight directors (when available) would be a disaster.

        Do you know any pilot in that category? Here it goes again: DO FOLLOW THE PROCEDURES.
        Ok, then, you and 3WE can argue that point. If I'm not mistaken, he may have spent some driving a Cessna.

        Comment


        • #94
          [Follow Procedures]

          Originally posted by Evan View Post
          Ok, then, you and 3WE can argue that point. If I'm not mistaken, he may have spent some driving a Cessna.
          Gabriel and I will not be arguing that procedures should have been followed, in fact we'll largely agree. In particular, the procedure described by ATL-the-Airbus-Captain to not_invoke memory items, but instead to keep things stable, forget memory checklists and carefully diagnose what is going on. Gabriel and I will note how that is pretty much the same as the Cessna rule of "First, and foremost, Aviate".

          We will also discuss how interesting it is that 65, 75 or 85% power (sort of like N1) and a nose-level attitude will give you FDnH flight. Again, we will revel at the similarity to A-320 numbers- as well as the ~2.5 degree divergence. We will state that we don't need to look it up in the 172 Book of Acronyms because, like ATL-the-Airbus-Captain, we felt it important to know such basic stuff for our incredibly average aircraft operation.

          While Gabriel and I have a nice discussion, you can discuss how "Aviate" must not be spoken as a broad solution as it is improvisational. Instead NAV ADR DISAGREE" ECAM83% N1 alpha prot AoA RECMAX THRUST RED ALT WTF is the correct way to handle an A-300 that has gone Y2K.

          I just don't know who you will discuss that with.
          Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

          Comment


          • #95
            Originally posted by 3WE View Post
            We will also discuss how interesting it is that 65, 75 or 85% power (sort of like N1) and a nose-level attitude will give you FDnH flight.
            Hopefully, this will help that discussion:

            Originally posted by BEA Final Report: AF447
            In addition, the thrust value of 84% N1 was lower than the thrust necessary for level flight (95% N1) due to the reduced mach ordered a few seconds before the autopilot disconnection, then the change to “Thrust Lock” mode at 2 h 10 min10.
            You might also discuss how the A320/330/340 lacks longitudinal stability in alternate law, and where all this might lead.

            Originally posted by BEA Final Report: AF447
            When there are no protections left, the aeroplane no longer possesses positive longitudinal static stability even on approach to stall.
            I don't think this is true of the 172, but what do I know.

            Comment


            • #96
              And these, IMHO, are design issues. We discussed them at lengths in the AF thread.

              That said, the way the AF crashed was unrelated to that. If you pull up all the time you are going to crash a 737-200 or a 172 too.

              --- 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


              • #97
                Originally posted by Gabriel View Post
                And these, IMHO, are design issues. We discussed them at lengths in the AF thread.

                That said, the way the AF crashed was unrelated to that. If you pull up all the time you are going to crash a 737-200 or a 172 too.
                No these things did not cause the AF447 crash but perhaps they will cause the next one. Can we at least stop calling this condition FDnH? The aircraft Bonin took over was not in stable flight xnd required CORRECT pilot action.

                But please respond to my more central point about procedure guiding pilots to use pitch and power rather than altitude, VSI and flight directors, because that may have been the thing that set the AF447 crash in motion and it is the reason I don't want pilots improvising here. Procedural discipline to prevent deception.

                Comment


                • #98
                  Originally posted by Evan View Post
                  No these things did not cause the AF447 crash but perhaps they will cause the next one. Can we at least stop calling this condition 100% FDnH? The aircraft Bonin took over was not in stable flight xnd required CORRECT pilot action.
                  Not unless we agree on the highlighted modifier. What do you think would have happened if they did NOTHING AT ALL and kept doing NOTHING AT ALL for a good period of time until they identified and called UAS and calmly pulled the QRH?

                  But please respond to my more central point about procedure guiding pilots to use pitch and power rather than altitude, VSI and flight directors,
                  Initially? Yes. Who ever said something different? Subsequently? At some point you will have to revert to altitude and hence VSI, that's what the "flight technique"in the QRH is for. Fight directors? Forget those, the first action in the QRH with or without memory items is kill the FD. And the 172 and Tomahawk don't have an FD (correction, the new 172 with the G1000 has a FD and all sort of automation).

                  because that may have been the thing that set the AF447 crash in motion and it is the reason I don't want pilots improvising here. Procedural discipline to prevent deception.
                  How? I really fail to see it. Address my point 2 in my previous previous post.

                  --- 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


                  • #99
                    Originally posted by Gabriel View Post
                    Address my point 2 in my previous previous post.
                    ...
                    Originally posted by 3BS visiting with Gabriel
                    I read something on the internet about the A-300 being longitudinally unstable around stall in some flight modes. However, my GUESS is that it might work OK to look at the Attitude indicator (just like is done on piston singles) and maintain your pitch and would GUESS that (with a familiar FDnH configuration) would be extremely effective and preventing stalls. It seems so useful to remember broad, fundamental concepts- so that you can focus on type specific stuff that deviates from broad fundamental concepts.

                    If I were to ever become an A-300 pilot, I would certainly want to study up on that. And, I hope I'd never be startled so much that I'd forget the basic rule to first and foremost Aviate...of course, you never know, it seems to repeat on rare occasion, even with the ATP types.

                    I suppose there is that argument that NAV ADR DISAGREE" ECAM83% N1 alpha prot AoA RECMAX THRUST RED ALT WTF is the correct way to handle an A-300 that has gone Y2K.
                    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                    Comment


                    • Originally posted by Gabriel View Post
                      Not unless we agree on the highlighted modifier. What do you think would have happened if they did NOTHING AT ALL and kept doing NOTHING AT ALL for a good period of time until they identified and called UAS and calmly pulled the QRH?
                      The way I see it, FDnH is not something you can modify. It either is or it isn't.
                      And I already said doing nothing is not the problem. The problem is improvising, which is not 'doing nothing'.

                      Initially? Yes. Who ever said something different?
                      It's not that you are disgreeing with flying pitch and power, it's that you seem to fail to see the trap, the deception, in not having a procedure to follow that eliminates using the unreliable instruments instead: a procedure that prevents pilots from improvising with those instruments. Do you see that?

                      How? I really fail to see it. Address my point 2 in my previous previous post.
                      Have you read this?

                      https://www.google.com/url?sa=t&rct=...aop1yjOliNkSWv

                      Comment


                      • Originally posted by Evan View Post
                        The way I see it, FDnH is not something you can modify.
                        Not surprisingly. So an imminent stall is the same as losing 0.5 knots per second?

                        I am curious to know, in your mind, what would have been the sequence of events (and timeline) had there been nobody in the cockpit.

                        It's not that you are disgreeing with flying pitch and power, it's that you seem to fail to see the trap, the deception, in not having a procedure to follow that eliminates using the unreliable instruments instead: a procedure that prevents pilots from improvising with those instruments. Do you see that?
                        Yes, but don't see how is that related to AF.

                        Have you read this?
                        No but I will. Thanks for the link.

                        --- 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


                        • Originally posted by Gabriel View Post
                          Not surprisingly. So an imminent stall is the same as losing 0.5 knots per second?

                          I am curious to know, in your mind, what would have been the sequence of events (and timeline) had there been nobody in the cockpit.
                          You mean nobody to improvise? Well, there would have been no initial pitch order and the initial roll would probably correct itself although further roll excursions would occur due to turbulence. I imagine the airplane would continue to lose speed however while the FBW increased pitch to hold load factor at level flight, thus increasing drag. I don't how much pitch would be needed to keep the altitude at that power setting, but with the stall AoA around 4.5°, there isn't really so much available. Would it eventually stall? Conceivably.

                          It's irrelevant however. Again, the issue isn't doing nothing. The issue is doing the wrong thing.

                          Comment


                          • Originally posted by Evan View Post
                            The way I see it, FDnH is not something you can modify.
                            Come again?

                            Comment


                            • Who is Barbara Faccini?

                              Comment


                              • Originally posted by ATLcrew View Post
                                Come again?
                                Sure. It's not in the FAR's so I can't quote the exact meaning of 'fat, dumb and happy', but it's not specfic to aviation either. Generally it means everything is going along fine without need for you to do much about it. If, for instance, you had to suddenly take control, try to make sense of a rapidly escalating situation in which turbulence is tossing you around and the ECAM is getting rather prolix, and the airplane is now decelerating and the instruments tell you things that aren't true, and its very, very dark and stormy and your heart is racing, that generally isn't what comes to mind when I think of the phrase, or even the acronym. In other words, either things are going along fine or they aren't and you need to step in and deal. Any sort of failure that carries the threat of an upset if not handled correctly doesn't seem to fit. So what don't I understand about aviation FDnH?

                                Comment

                                Working...
                                X