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  • Australian Senate training and experience and requirements after looking at AF447 evidence.

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    • Originally posted by Evan View Post
      Based on what we know so far, this accident would not have happened in an A330 with a competent crew at the controls. Do you see my point?
      Now tell me how many "competent crews" are out there. Have a number? Easy to use a phrase like that, but how does the public get any use out of that information. I'm betting both the passengers and Air France thought AF447 believed this crew was competent.

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      • Originally posted by Black Ram View Post
        Maybe a little over-dramatized, but I would think a re-trim would be necessary. Read the next sentence, which explains it is not hard, but presents extra workload to an aircrew, dealing with an emergency.

        Since you are at it:



        Not that airflow over the wing is not an absolute must, but isn't the Bernoulli Principle explanation of lift alone by itself oversimplified and outdated? Do classic 747 pilots believe in equal transit time?

        http://www.grc.nasa.gov/WWW/k-12/airplane/wrong1.html

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        • Originally posted by Black Ram View Post
          It does really seem they have a personal interest in behaving that way. I have very high respect for Sully, FO Skiles, the cabin crew, the airline for its safety culture and happening to be flying an aircraft with inflatable rafts, etc. After all, an A320 is not smart enough to decide where it is best to land. The pilots decided what to do and the A320 executed their decisions perfectly, better than any human could. US1549 is a perfect example of outstanding airmanship and advanced technology coming together in harmony.
          Sully said that he would have ditched any airplane equally well.

          I don't know what Sully would have done, but what I do know is that, in ANY airplane:

          - to glide
          - and level-off
          - a few feet above
          - a flat surface
          - and hold it there
          - while bleeding off speed
          - until the plane smoothly touches down
          - at no specific spot on such surface
          - at a speed slightly above stall,

          is not only possible, but fairly easy indeed.

          --- 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 ---

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          • I downloaded the report and just had time for a quick scan, but it is actually fairly obvious from the report that the Airbus alpha protection played a key role here. If Sully had been piloting a 737 instead of an A320, a stall could have resulted. Here's why:

            When thrust is lost to both engines, the pilot is trained to fly at green dot to extend the glide as much as possible without getting into a dangerous AoA. Sully was flying well under green dot and between 15 and 19kts BELOW VLS in the last 200'. The alpha protection began limiting the AoA at 150ft; they were in alpha prot for the last 150ft. Sully continued to apply increasing backpressure until reaching the full aft stop at around 50'. (The engines kept producing adequate electrical power and hydraulic pressure to remain in normal law).

            According to FDR data, the airplane touched down on the Hudson River at an airspeed of 125 KCAS with a pitch angle of 9.5. Structural ditching certification criteria calls for targeting a flight path angle of -.5 at touchdown. Sully was at -3.4

            The NTSB concludes that the captain’s difficulty maintaining his intended airspeed during the final approach resulted in high AOAs, which contributed to the difficulties in flaring the airplane, the high descent rate at touchdown, and the fuselage damage.
            Again, I don't mean to take anything away from Capt. Sullenberger. When you consider in the stress factor, I think these speed and AoA deviations are quite understandable. But, based on what I've learned thus far, it seems a bit out-of-line for him to be placing any blame on the aircraft (if he is in fact doing that). The one thing that bothers me is the fact that alpha protections had to kick in at all, because they wouldn't have been available on the 737. I would be very interested to hear more specifically what he has to say against the Airbus systems.

            But it seems pretty clear that the A320 systems were beneficial, and perhaps a critical factor here. Any difficulties he encountered in flaring were due to his erroneously low airspeed and high AoA, not due to undesirable system limitations. I need to read the report more thoroughly when I can find the time.

            Interesting note: In one of the simulator tests done after the crash, a -0.2 touchdown flightpath angle was achieved by an Airbus test pilot who used a technique that involved approaching the water at a high speed, leveling the airplane a few feet above the water with the help of the radar altimeter, and then bleeding off airspeed in ground effect until the airplane settled into the water.

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            • Originally posted by Evan View Post
              From the A320 FCTM:
              Evan, I uderstand that. I don't see the dirct mode enywhere though.

              I'm ok with this flare mode. I'd be ok with a direct mode for flare. I don't understand having both at the same time, and I don't see that happening from your quote.

              --- 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 ---

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              • Originally posted by Gabriel View Post
                Evan, I uderstand that. I don't see the dirct mode enywhere though.

                I'm ok with this flare mode. I'd be ok with a direct mode for flare. I don't understand having both at the same time, and I don't see that happening from your quote.
                Oh yeah, I didn't mean to imply that FLARE law was the same as DIRECT LAW, only that the pitch law is a direct stick-to-elevator relationship. Alpha floor is lost, and the THS is frozen, but the AoA protections are still there.

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                • Originally posted by Evan View Post
                  Oh yeah, I didn't mean to imply that FLARE law was the same as DIRECT LAW, only that the pitch law is a direct stick-to-elevator relationship.
                  I don't see that either.

                  --- 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
                    I don't see that either.
                    It's in the A330 FCOM. It says "direct stick-to-elevator relationship (with some damping provided by load factor and pitch rate feedbacks)" I am again assuming the basic control law is the same for the A320, as Airbus advertises a commonality in flight control across their FBW aircraft. But perhaps it is still pitch-rate demand...

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                    • [Off-topic]

                      One thing I just noticed on the CVR transcript, Sully say's this just 30 seconds before the bird strike:

                      15:26:37 HOT-1
                      uh what a view of the Hudson today.
                      He got an even better view of it a few minutes later.

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                      • Originally posted by Evan View Post
                        [Off-topic]

                        One thing I just noticed on the CVR transcript, Sully say's this just 30 seconds before the bird strike:



                        He got an even better view of it a few minutes later.
                        and you have the capacity for humor!! outstanding!!

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                        • When passing through 100' RA, pitch goes into FLARE mode, which is a direct stick to elevator relationship with some damping provided by load factor and pitch rate feedbacks. When passing 50' RA, a slight nose down elevator order is applied, requiring the pilot to apply backpressure to maintain the flight path, thus reproducing conventional aircraft characteristics. That's in the A330 FCOM.
                          So, let me get this right - in a hudson (or similar land) situation, a pilot may unintentionally leave himself without flare authority?

                          Full backstick was applied, and the aircraft protected against the stall (which is a good thing). However, upon reaching the flare, if you already had full backstick, and you would have no further movement available. Indeed, if the airfract actively pitched down, to create a "normal" flare environment, it could actually pitch you further down?

                          One thing we can't really say, however, is how successful it would have been on a 737. Sully had the protections, and he KNEW he had the protections. A 737 pilot faced with the same situation would, hopefully, have been aware to not stall, and the stall warnings would have been significant compared to the Airbus, where it isn't so critical.

                          I do agree that the alpha protections were definitely of assistance.

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                          • There you go, yo are not that old-fashioned after all.

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                            • Originally posted by Evan View Post
                              But, based on what I've learned thus far, it seems a bit out-of-line for him to be placing any blame on the aircraft (if he is in fact doing that).
                              I think Sully was just keeping silent, but apparently it's trendy to blame that specific make of aircraft at the union.

                              Comment


                              • Originally posted by MCM View Post
                                One thing we can't really say, however, is how successful it would have been on a 737. Sully had the protections, and he KNEW he had the protections.
                                I think this point has been overlooked repeatedly, and posing the counterfactual "What if it had been a 737?" doesn't make much sense. Sully wasn't on a 737, he was on an Airbus, and he flew the Airbus in precisely the manner necessary, with protections in place and knowing how they would respond, to have a safe landing.

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