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  • ...a scary inference that it might be "What's it doing now"

    By Siva Govindasamy and Tim Hepher SINGAPORE/PARIS (Reuters) - Investigators probing the crash of an AirAsia jetliner are examining maintenance records of a key part of its automated control systems, and how the pilots may have handled the plane if it failed, two people familiar with the matter said. "There appears to be some issue with the FAC," a person familiar with the investigation said, adding that more information was being sought from the manufacturer and airline. Indonesia has said the Airbus A320 jet climbed abruptly from its cruising height and then stalled, or lost lift, before plunging out of control into the Java Sea, killing all 162 people on board. A second person familiar with the probe said investigators were looking at how the pilots dealt with the chain of events leading up to the crash.
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

    Comment


    • Originally posted by 3WE View Post
      ...a scary inference that it might be "What's it doing now"

      http://news.yahoo.com/exclusive-aira...--finance.html
      - We have a flight computers failure, take control.
      - [turns knobs, pushes button, flips switches].
      - No, no, take MANUAL FLIGHT control. Fly the plane as a pilot would.
      - You mean that I have to put my hands in that stick?

      --- 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 3WE View Post
        ...a scary inference that it might be "What's it doing now"

        http://news.yahoo.com/exclusive-aira...--finance.html
        "There appears to be some issue with the FAC," a person familiar with the investigation said, adding that more information was being sought from the manufacturer and airline.
        Oh, MY GOD!!! A GLITCH!!!!! Oh how SCARY!!!!!

        Now for some FACTS:
        There are currently no emergency AD's issued for the a320. An AD was issued in October because under certain conditions it was found that relentless rudder inputs could result in structural failure on the vertical stabilizer despite the intervention of the FAC's. The AD updates the FAC logic to provide an aural "stop rudder input" message as well as some improvements to the logic.

        Neither the rudder not the stabilizer detached on the AIrAsia flight. So, sorry, non-issue.

        Whatever happened to AIrAsia, it involved a steep climb. Elevator is controlled by the SEC's, not the FAC's.

        The FAC's control yaw and provide speed calculations to the envelope protections and other protections such as flaps extention. If the FAC's are lost you get alternate law. That is, if BOTH FAC's are lost. For this to happen, you need either a fantastic coincidence or a common vulnerability factor.

        Both FAC's depend on the ADIRU's to be in agreement. The ADIRU's depend on air data sensors to function. The pitots are equally vulnerable to ice ingestion. When you lose pitot function, you lose ADIRU agreement, you lose the FAC's.

        Stop me when you begin to see the familiar aspect....

        "The aircraft remains fully controllable if you lose the two FACs," an Airbus spokesman said by email.
        "The consequence of losing the two FACs is that the pilot has to fly manually like a conventional aircraft, which by definition has no flight envelope protection."
        Yes, unless they are not properly trained by an airline with a flawed safety culture.

        Or you could blame the airplane and start another round of ignoramus scarebus dialog.

        Comment


        • "The consequence of losing the two FACs is that the pilot has to fly manually like a conventional aircraft, which by definition has no flight envelope protection.
          That's not true.
          If both FACs fail you will be in alternate law. Alternate law is not how a conventional airplane behaves.

          Alternate law lacks speed or AoA stability like a conventional airplane. Plus, if the reason for the downgrade was speed data, you'll also loss the slow speed stability soft protection.

          Add the level of complexity of changing from normal to alternate that is also lacking in the conventional plane, and you can have pilot confusion wondering "Why the plane pitches up past 30°? It never does that in the sim. What is this stall warning and why is it sounding? It never does that in the sim", and so on...

          --- 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
            That's not true.
            If both FACs fail you will be in alternate law. Alternate law is not how a conventional airplane behaves.

            Alternate law lacks speed or AoA stability like a conventional airplane. Plus, if the reason for the downgrade was speed data, you'll also loss the slow speed stability soft protection.
            By 'conventional airplane' he defines that he means one without envelope protections, one you have to fly carefully, with your basic airmanship. Gabe you know that speed stability is not a deciding factor in emergency situations in which the crew is focused on flying the plane with their solid airmanship*.
            Add the level of complexity of changing from normal to alternate that is also lacking in the conventional plane, and you can have pilot confusion wondering "Why the plane pitches up past 30°? It never does that in the sim. What is this stall warning and why is it sounding? It never does that in the sim", and so on...
            Any pilot asking these questions is unfit to pilot an A320 and untrained on basic reversion laws which must be learned in the sim.

            *Using the Gabriel definition of Airmanship which includes procedural discipline and CRM.

            Comment


            • Originally posted by Evan View Post
              Neither the rudder not the stabilizer detached on the AIrAsia flight. So, sorry, non-issue.
              Yes, but that's not the point. The point is, the FAC failures could have been responsible for degrading to alternate law. Yes, then we look into the training, but anyway, the pilots are then in control, and the weather wasn't very nice.
              A few other important facts (as I mentioned earlier) are that FAC and/or ELAC components had been swapped on that airframe, and that it has a history of FAC and/or ELAC faults.
              Another possibility is a runaway rudder trim, which might explain the wide left turn.
              Demonstration of Rudder Trim increasing with each power interrupt to the FAC (Flight Augmentation Computer).


              Again, this all is not catastrophic. But neither was pitot ice blockage.

              Comment


              • Originally posted by Black Ram View Post
                Yes, but that's not the point. The point is, the FAC failures could have been responsible for degrading to alternate law. Yes, then we look into the training, but anyway, the pilots are then in control, and the weather wasn't very nice.
                A few other important facts (as I mentioned earlier) are that FAC and/or ELAC components had been swapped on that airframe, and that it has a history of FAC and/or ELAC faults.
                Another possibility is a runaway rudder trim, which might explain the wide left turn.
                Demonstration of Rudder Trim increasing with each power interrupt to the FAC (Flight Augmentation Computer).


                Again, this all is not catastrophic. But neither was pitot ice blockage.
                Well, if not ADIRS related, that would involve a simultaneous failure of both FAC's for some other reason. That's like a simultaneous failure of both engines, only far less likely becuase they are not exposed to things like birds, ash or fuel starvation. I can't imagine a scenario that would cause this, can you?

                I suspect the turn was induced by stall.

                The real issue that I think we are going to be soon discussing is how, five years after AF447, a major operator can still be allowing pilots to fly these aircraft without the training and practiced skills needed under such scenarios, essentially all the things recommended by the AF447 investigation.

                The interim report was due today, so hopefully in the next day ot two....

                Comment


                • Originally posted by Evan View Post
                  Well, if not ADIRS related, that would involve a simultaneous failure of both FAC's for some other reason. That's like a simultaneous failure of both engines, only far less likely becuase they are not exposed to things like birds, ash or fuel starvation. I can't imagine a scenario that would cause this, can you?
                  Something to do with improper maintenance? There's talk of faulty units, swapping (not very clear exactly what got swapped and from where)


                  Originally posted by Evan View Post
                  The real issue that I think we are going to be soon discussing is how, five years after AF447, a major operator can still be allowing pilots to fly these aircraft without the training and practiced skills needed under such scenarios, essentially all the things recommended by the AF447 investigation.
                  Yes, very possible

                  Originally posted by Evan View Post
                  The interim report was due today, so hopefully in the next day ot two....
                  I read somewhere this interim report won't include analysis from the FDR and CVR. Hopefully that won't be the case

                  Comment


                  • Originally posted by Black Ram View Post
                    Something to do with improper maintenance? There's talk of faulty units, swapping (not very clear exactly what got swapped and from where)
                    There is one scenario I see for this. The MMEL allows for dispatch with FAC 2 inoperative. If that was the case a single remaining FAC 1 failure in flight would fit your scenario. That would cause a reversion to alternate law and require flight without envelope protections (but I think autoflight is still possible there). That is the MMEL allowance. AirAsia might have a stricter MEL allowance.

                    It wouldn't explain the sudden climb, the climb rate or the lack of coms however.

                    Comment


                    • Interestingly though maybe irrelevent, the EASA issued AD 2014-0237R1 for pitot probe replacement on the A320 in December. It calls for replacement of either the Thales -AA or -BA probes but does not specify what to replace them with (it specifies a service bulletin). It is not an emergency directive. It is not a current FAA AD. I believe it is a DGAC inspired directive. At any rate it confirms that weather-related pitot failure at cruise altitude continues to be an issue.

                      Comment


                      • Originally posted by Evan View Post
                        Any pilot asking these questions is unfit to pilot an A320 and untrained on basic reversion laws which must be learned in the sim.
                        Any pilot pulling up like AF did is unfit to pilot an airplane and untrained on basic airmanship and aerodynamics that must be learned in a C-172

                        And you want to train him on A320 reversion laws in a level-D sim?????

                        --- 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
                          Any pilot pulling up like AF did is unfit to pilot an airplane and untrained on basic airmanship and aerodynamics that must be learned in a C-172

                          And you want to train him on A320 reversion laws in a level-D sim?????
                          Concur.

                          I saw the word "untrain" above. Is that where they are untrained from their first ever flying lesson to not pull up relentlessly?
                          Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                          Comment


                          • Originally posted by Gabriel View Post
                            Any pilot pulling up like AF did is unfit to pilot an airplane and untrained on basic airmanship and aerodynamics that must be learned in a C-172

                            And you want to train him on A320 reversion laws in a level-D sim?????
                            Have you been drinking 3WE's koolaid? Did I ever say I wanted a pilot who doesn't grasp basic airmanship to fly by procedures alone (which is not possible by the way)? What I said was:
                            Basic airmanship goes without saying.
                            However, basic airmanship without training on type is recipe for disaster. Basic airmanship without knowing control law reversions creates this situation:
                            Originally posted by Gabriel
                            Add the level of complexity of changing from normal to alternate that is also lacking in the conventional plane, and you can have pilot confusion wondering "Why the plane pitches up past 30°?
                            The proper answer to that question is: "How did you get into the A320 cockpit and get the hell out!"

                            Do you really think the pilot of AF447 didn't have the most basic airmanship and pulled up ignorant of basic stall dynamics? He did whatever he did, including ignoring stall warnings because of confusion, disorientation, all those human factors. He didn't have advanced airmanship, the kind you need to fly passengers around. You don't have advanced airmanship until you understand both basic airmanship and human factors and realize that deep training on-type and procedures on-type are necessary to overcome human factors, preserve situational awareness and maintain CRM.

                            I'm sorry but anybody that doesn't get that by now should stick to basic airmanship, fly GA and stay the hell out of the passenger business.

                            But I'm tired of this eristic argument. 3WE trolls me on the unimportant threads and I'm willing to play but lets keep it off this thread, shall we?

                            Comment


                            • Originally posted by Evan View Post
                              The proper answer to that question is: "How did you get into the A320 cockpit and get the hell out!"
                              By following the training & qualification procedures specified by his employer for becoming an A320 pilot?
                              Be alert! America needs more lerts.

                              Eric Law

                              Comment


                              • Originally posted by Gabriel View Post
                                ... basic airmanship and aerodynamics that must be learned in a C-172
                                C-172M or C-172P?
                                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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