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  • Stall avoided by advanced technique

    A transport category lifts off. The PF commands "gear up" and the PM responds by moving the lever to the "up" position. Except the wrong lever.
    He just retracted the flaps and slats.

    The stickshaker activates. At such a low altitude, minimizing altitude loss is paramount. The throttles being already at TOGA, the PF sets the standard 10 deg nose-up pitch for the "approach to stall" procedure. That doesn't help to reduce the AoA enough, the plane stalls, crash, burns and everybody dies.

    That would have been the possible outcome of this incident just a few years ago which, instead, was only an incident.

    The pilot, instead, lowered the nose to reduce the AoA and silence the stickshaker. That is, he followed the new stall procedure for transport category airplanes, which is and was the old and universal procedure everywhere (but in transport category airplanes until a few years ago).

    In a stall/approach to stall situation there is no better way to preserve altitude than not stalling. If that is not good enough, stalling for sure will not be any better.

    http://avherald.com/h?article=486ff90e&opt=0

    --- 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 ---

  • #2
    Originally posted by Gabriel View Post
    A transport category lifts off. The PFNM (Pilot-Flying-Not-Monitoring) commands "gear up" and the PNQ (Pilot-Not-Qualified) or possibly PNR (Pilot-Not-Rested) responds by moving the lever to the "up" position. Except the wrong lever.
    He just retracted the flaps and slats.
    Fixed.

    I think that scenario is a bit exteme. Even with the old procedures (powering out of stall), if a pilot gets stickshaker at full-power, I don't think he would just sit there at 10° and stickshaker until the thing fell through. Assuming, that is, that the pilot understood what stall was...

    BYW, the AvHerald altitudes must be wrong, eh?

    Comment


    • #3
      Originally posted by Evan View Post
      Fixed.
      Evan, something that is highly unlikely is not something that is very unlikely to happen in general. It is highly unlikely to happen in any SINGLE instance, but given enough repetitions it is happening is not just likely: it WILL happen.

      This mistake is something that a professional crew, well trained, very responsible, that takes their job very seriously, and is well rested, will make once every.. what do you like? 100,000, 1 million, 10 million take-offs? Of course, no single pilot will ever achieve these many take-offs, but put enough crews and the magic number will be reached some time sooner or later, and then again, and then again with this mistake happening, on average, once every X take offs.

      I think that scenario is a bit extreme. Even with the old procedures (powering out of stall), if a pilot gets stickshaker at full-power, I don't think he would just sit there at 10° and stickshaker until the thing fell through. Assuming, that is, that the pilot understood what stall was...
      3WE can tell you about what professional transport category pilots said about lowering the nose to recover from an approach to stall. They would not lower the nose. The would not risk losing altitude and ground contact. They did not realize that that was the best way to guarantee ground contact.

      BYW, the AvHerald altitudes must be wrong, eh?
      Why? Note MSL vs AGL.

      --- 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


      • #4
        Originally posted by Gabriel View Post
        Evan, something that is highly unlikely is not something that is very unlikely to happen in general. It is highly unlikely to happen in any SINGLE instance, but given enough repetitions it is happening is not just likely: it WILL happen.
        Yes, that's the philosophy. A single pilot will inevitably make an unthinkable error just as a single engine will inevitably fail. That's why we have two engines and two pilots. But if the pilot-flying does not cross-check the actions of the pilot-monitoring (and the gear handle is right there on the display panel) we have a dual-pilot failure. This is not supposed to happen. This is what CRM is for. That should be habit. There are many lives in their hands and look how close this one came.

        Why? Note MSL vs AGL.
        Brisbane is 13ft AMSL. I don't get you...

        Comment


        • #5
          Originally posted by Evan View Post
          Yes, that's the philosophy. A single pilot will inevitably make an unthinkable error just as a single engine will inevitably fail. That's why we have two engines and two pilots. But if the pilot-flying does not cross-check the actions of the pilot-monitoring (and the gear handle is right there on the display panel) we have a dual-pilot failure. This is not supposed to happen. This is what CRM is for. That should be habit. There are many lives in their hands and look how close this one came.
          Two engines can, have and will fail, even if there is nothing wrong with the engines themselves.
          Three pitots can, have and will fail, even if there is nothing wrong with the pitots themselves.
          Two pilots can, have and will fail, even if there is nothing wrong with the pilots themselves.
          In all three cases, of course, having something wrong with the Xs themselves highly increases the chances of all Xs failing.
          I don't know what was the case with these pilots, but the pilots weren't necessarily tired, undertrained, or otherwise not qualified. Again, maybe they were.

          In any event, there are additional layers of safety. Airplanes remain controllable and can glide after loosing all engines, airplanes can be flown with no speed indication, and a clear stall warning will activate when the plane approaches to stall and that situation can be recovered by reducing the AoA.

          By the way, according to the ATSB report, the climb shallowed when the pilot reduced the pitch to 6.5 deg but it remained positive (if barely) at all times.

          Brisbane is 13ft AMSL. I don't get you...
          I stand corrected.

          --- 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


          • #6
            If the pilot of the BA 777 flight BA38 that crashed at Heathrow when the fuel froze and cut out the engines had not lowered the nose to gain some airspeed to get over the fence then it's most likely that Hatton Cross Underground Rail Station would not exist and there would have been lots of fatalities.
            If it 'ain't broken........ Don't try to mend it !

            Comment


            • #7
              Originally posted by Gabriel View Post
              Two engines can, have and will fail, even if there is nothing wrong with the engines themselves.
              Two pilots can, have and will fail, even if there is nothing wrong with the pilots themselves.
              Yes, but then there is something very wrong with the 'environment'.

              You posted this to show how the new pitch-reduction-priority stall warning procedures are saving lives. I couldn't agree more.
              But, as usual, I am alarmed at the rather stunning lack of competence leading up to the event. I'm not talking about making mistakes (although this one is a real masterpiece), I'm talking about a lack of CRM competence, the one thing that seems to always lay behind fatal pilot error accidents. The PF called for gear-up. He also has to confirm that this has been done. With his eyes at least. If he doesn't, he has poor basic airmanship. He might as well just pull up relentlessly because it can get him into the same situation: Stall warning.

              The point you are making about procedure is clear, but let's not forget the larger point: A modern airline pilot should never get into a valid stall warning outside of windshear.

              It's not just a stall warning. It's a culture warning.

              Comment


              • #8
                Originally posted by brianw999 View Post
                If the pilot of the BA 777 flight BA38 that crashed at Heathrow when the fuel froze and cut out the engines had not lowered the nose to gain some airspeed to get over the fence then it's most likely that Hatton Cross Underground Rail Station would not exist and there would have been lots of fatalities.
                Yep (except that I would say "to reduce the AoA and silence the stickshaker that had already triggered", instead of "to gain some speed", although both concepts are obviously related one to the other), that plus the Captain raising the flaps from a landinguish setting to a takoffish setting, thus reducing the drag and increasing the glide ratio.

                --- 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


                • #9
                  Originally posted by Gabriel View Post
                  ...3WE can tell you about what professional transport category pilots said about lowering the nose to recover from an approach to stall...
                  Indeed, I can.

                  But I tend to generalize and say that it works in a wide range of aircraft. That doesn't work for Evan.

                  And to clarify- the famed incident you cite, what the pilot actually went on to say was, "one should follow the procedure- written by the engineers who built the plane...

                  ...I think they know a lot more about how to operate the specific plane than you or your ass-hat buddy, Gabriel, do".
                  Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                  Comment


                  • #10
                    Originally posted by Evan View Post
                    ...A modern airline pilot should never get into a valid stall warning outside of windshear...

                    True that...

                    ...but nevertheless, it happens and then they proceed with that relentless pull up deal, which makes me wonder how they can forget such basic basic things.

                    Then I see you on an acronym orgy and citing long lists of checklists and exceptions, I see how that might just happen.

                    More training is needed...(except on basics).
                    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                    Comment


                    • #11
                      Originally posted by Gabriel View Post
                      Two engines can, have and will fail, even if there is nothing wrong with the engines themselves.
                      Three pitots can, have and will fail, even if there is nothing wrong with the pitots themselves.
                      Two pilots can, have and will fail, even if there is nothing wrong with the pilots themselves.
                      In all three cases, of course, having something wrong with the Xs themselves highly increases the chances of all Xs failing.
                      Evan has never made a mistake and has no concept that normal people do (in spite of their best efforts not to).
                      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                      Comment


                      • #12
                        Originally posted by 3WE View Post
                        Evan has never made a mistake and has no concept that normal people do (in spite of their best efforts not to).
                        Originally posted by Evan
                        But, as usual, I am alarmed at the rather stunning lack of competence leading up to the event. I'm not talking about making mistakes (although this one is a real masterpiece), I'm talking about a lack of CRM competence, the one thing that seems to always lay behind fatal pilot error accidents.
                        3WE has never actually read any of my posts and has no concept of what is contained in them.

                        Comment


                        • #13
                          Originally posted by Evan View Post
                          Brisbane is 13ft AMSL. I don't get you...
                          I also don't get how the airplane made it to almost 3,000' with the gear apparently hanging (with the resulting noise) and no flaps before anyone noticed.

                          Comment


                          • #14
                            Originally posted by ATLcrew View Post
                            I also don't get how the airplane made it to almost 3,000' with the gear apparently hanging (with the resulting noise) and no flaps before anyone noticed.
                            Those numbers must have an extra zero. 280 and 270ft would make more sense there.

                            Comment


                            • #15
                              Originally posted by Evan View Post
                              Those numbers must have an extra zero. 280 and 270ft would make more sense there.
                              Maybe, but then AGL would be more relevant. Granted, in this case it's almost the same thing.

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