Announcement

Collapse
No announcement yet.

AirAsia flight missing

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

  • Originally posted by EconomyClass View Post
    Probably too late for this question, but they are running Why Planes Crash on Weather Channel, including the Delta plane slammed into the ground by wind shear in Dallas. Since there was a thunderstorm here, could wind shear have caught it and slammed it into the ocean?
    I will not say "impossible", but what's the closest to that?

    Regarding to "why planes crash", well, they crash because they can crash and they fly a lot.

    Everything that can happen will eventually happen if tried enough times*, and after it happened once it will eventually happen again if tried enough times* again.

    *enough times = until it happens

    --- 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 Evan View Post
      In aviation is is defined as a 30 kt or greater change in airspeed or a 5kt change in vertical speed (a definition expected to be improved by Gabriel).
      Well, I've never heard a quantitative definition of windshear, but the definition should include the space where said change takes place. The difference between a 30 kts windshear and a 30 kts wind gradient is that one takes place in a couple of feet and the other in a couple hundreds of feet.
      With significant height, a pilot should be able to recover before the ground rises to meet him. If he is in a full stall, they still should be able to recover before the ground rises to meet him. If missing some control surfaces, that is a different story.
      Fixed.

      --- 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 Evan View Post
        Windshear can occur at any altitude. In aviation is is defined as a 30 kt or greater change in airspeed
        So I'm short final in a 172 on a gusty day and suddenly loose 25 kts of speed, but that's not wind shear?
        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

        Comment


        • The issue with most classic wind shear crashes isn't the just the wind but that the plane is slow and low to the ground and often has the engines powered way back, meaning it takes several seconds to power up.

          But for cruise, where you may have a good chunk of extra airspeed, engines humming at a good clip and tons upon a tons of extra altitude- to be 'simply slammed into the ocean' (with the airplane perfectly intact) isn't really viable.
          Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

          Comment


          • Originally posted by Evan View Post
            With significant height, a pilot should be able to recover before the ground rises to meet him. If he enters and remains in a full stall or is missing some control surfaces, that is a different story.
            Clarified.

            Comment


            • Originally posted by Evan View Post
              Clarified.
              Evan, I sent you a PM.

              --- 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


              • Reportedly the tail has been found and confirmed.

                Comment


                • Pings

                  Yeah seems like the tail has been found but apparently it was found by sonar and not by pings from the black boxes.

                  Can anyone explain why there would not be pings heard, if they are located in the tail?

                  Comment


                  • Originally posted by opa-opa View Post
                    Can anyone explain why there would not be pings heard, if they are located in the tail?
                    They fell out during the crash?
                    They broke during the crash?
                    The ping detection equipment was faulty?
                    Poor maintenance meant batteries weren't replaced so they stopped working much sooner than expected?

                    Can't say for sure if any of those are the answer, but they would certainly be explanations.

                    Comment


                    • Originally posted by opa-opa View Post
                      Yeah seems like the tail has been found but apparently it was found by sonar and not by pings from the black boxes.

                      Can anyone explain why there would not be pings heard, if they are located in the tail?
                      Smashed to bits?

                      Comment


                      • Originally posted by ultraflight View Post
                        Smashed to bits?
                        Kind of unlikely given the construction of the devices and the fact that a structure identifiable as the tail was found.

                        Arrow

                        Comment


                        • Originally posted by Evan View Post
                          They could have encountered an updraft, suddenly increasing AoA
                          Would it be too much if I asked someone to explain how updrafts lead to an increase in AOA? Don't gliders use them to climb?

                          I can see how an updraft can lead to an unsafe altitude (it must have been a monster updraft if that's what caused the climb), but then, if in normal law, the FBW should be correcting for it?


                          Also, has anyone thought of freezing of the AOA vanes as a cause? There's this from a few months ago:

                          Aviation Herald - News, Incidents and Accidents in Aviation


                          A bit trickier than UAS.

                          Comment


                          • Originally posted by Black Ram View Post
                            Also, has anyone thought of freezing of the AOA vanes as a cause? There's this from a few months ago:

                            Aviation Herald - News, Incidents and Accidents in Aviation


                            A bit trickier than UAS.
                            Which is also similar (on the surface, to a novice such as myself anyway) to the 2008 Airbus 320 accident posted here - frozen AoA vanes at any rate.

                            Comment


                            • Originally posted by sjwk View Post
                              Which is also similar (on the surface, to a novice such as myself anyway) to the 2008 Airbus 320 accident posted here - frozen AoA vanes at any rate.
                              Yes. Even though I see these important differences:

                              1) 2008 was a test flight, they were actually testing the Alpha protections
                              2) 2008 had less altitude, I believe, while the LH flight was at cruising altitude, as was the Air Asia flight
                              3) The freezing of the AOA vanes on the 2008 flight was due to faulty maintenance, forcing water inside the vanes' mechanism, while LH seems to have encountered freezing during normal operations (the investigation should hopefully determine it for sure).

                              Comment


                              • Originally posted by Black Ram View Post
                                Would it be too much if I asked someone to explain how updrafts lead to an increase in AOA?
                                It's straightforward. An updraft DO increase the AoA.
                                The AoA is the angle between let's say the deck and the relative wind.
                                If you are flying at cruise (constant altitude) with the nose 2 degrees up, then the relative wind, which is horizontal, comes from 2 degrees below the nose.

                                If an updraft hits, then the wind will come not horizontally anymore but more from below. Voila, the AoA has just increased.

                                --- 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

                                Working...
                                X