Announcement

Collapse
No announcement yet.

TransAsia airplane crashes in Taipei (ATR 72)

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

  • Originally posted by Evan View Post
    So much rubbish, it's hard to imagine that this was once a legitimate thread about gross pilot error and training difficiencies.
    yeah, funny that!

    Comment


    • Originally posted by Evan View Post
      So much rubbish, it's hard to imagine that this was once a legitimate thread about gross pilot error and training difficiencies.
      Oh, this thread is ALL about training...

      ...and it's effect on GROSS, sustained errors against procedure AND fundamentals, as well as split-second brain-fart errors when basically following procedures and fundamentals.

      Quite the challenge to train folks for all of that.

      The thread is still quite legitimate except for, perhaps, the thread title.
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

      Comment


      • Originally posted by The 25-years-ago section in my March issue of an obscure US flying magazine
        In "Safety in Numbers" we delved into the single-versus-twin debate to try and find out once and for all if two engines really are better than one. The answer? You're more likely to crash in a single -engine airplane after and engine failure, but your odds of surviving that crash are grater than those during an engine-out accident in a twin.
        OK
        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

        Comment


        • I can actually see how that would be the case.

          In a single, the engine fails and the pilot instantly knows the airplane is going to be landing sooner than originally planned. Pilot selects the best available site (hopefully maybe), plane "lands", plane hurt, pax walk away. Or in other words, the plane returns to Earth in a more-or-less controlled gentle fashion.

          In a twin, the pilot "knows" the plane can continue flying on one engine and attempts to do so. Pilot screws up (as seen in the subject of this thread and many other instances), plane stalls and often spins, and returns to Earth in a much more violent fashion that's not conducive to pax continuing to live.
          Be alert! America needs more lerts.

          Eric Law

          Comment


          • New footage from a rooftop:

            復興航空在墜機前失去動力,低空飛過附近住宅,高度比大樓還要低,像是電影場景一般驚險的從大樓和大樓之間穿越,住戶表示,看到飛機出現在窗戶邊實在嚇壞了,還以為是自己看錯,但過沒多久就聽到墜機巨響,慶幸自己躲過一劫。

            Comment


            • Originally posted by elaw View Post
              I can actually see how that would be the case.

              In a single, the engine fails and the pilot instantly knows the airplane is going to be landing sooner than originally planned. Pilot selects the best available site (hopefully maybe), plane "lands", plane hurt, pax walk away. Or in other words, the plane returns to Earth in a more-or-less controlled gentle fashion.

              In a twin, the pilot "knows" the plane can continue flying on one engine and attempts to do so. Pilot screws up (as seen in the subject of this thread and many other instances), plane stalls and often spins, and returns to Earth in a much more violent fashion that's not conducive to pax continuing to live.
              Concur, but thought they stated the obvious and ignored the bottom line.

              Mathematics that:

              T1) In a twin you have roughly twice the chance of an engine failure.
              times
              T2) A reduced chance of crashing.
              times
              T3) An increased chance of a deadly crash.

              Versus

              S1) A reduced chance of an engine failure
              times
              S2) A greatly increased chance of crashing
              times
              S3) A decreased chance that the crash is deadly.

              Yeah, all that makes perfect sense. But, what's the bottom line after you do the ciphering? (Edit: Probably need to recognize that there may not be "one clear" bottom line, but would like to see that discussed.)

              Footnote 1: In general, for twins, the Airlines do an outstanding job with T2.

              Footnote 2: Piesels videos show the sad, strong, downward-but-nose-up trajectory that was less obvious with the aircraft viewed as it was coming somewhat towards the highway...Yeah, a relentless pull up, but not really a mindless, incomprehensible one.
              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

              Comment


              • Originally posted by elaw View Post
                In a twin, the pilot "knows" the plane can continue flying on one engine and attempts to do so. Pilot screws up (as seen in the subject of this thread and many other instances), plane stalls and often spins, and returns to Earth in a much more violent fashion that's not conducive to pax continuing to live.
                While that is certainly the scenario 3WE is referring to when citing the higher fatality rate of a twin engine crash due to loss of control, that has nothing to do with the subject of this thread. This is a case of CFIT due to loss of power in both engines. Pilot error was in power management, not flight controls. The final roll before impact was the inevitable wing-stall resulting from a need to clear buildings, not an assymetrical center-of-thrust/p-factor yaw issue.

                I don't think the single vs twin argument has any bearing on this crash.

                Comment


                • Originally posted by Evan View Post
                  I don't think the single vs twin argument has any bearing on this crash.
                  Seriously?

                  Can you cite a case where a single-engine aircraft has crashed due to the pilot shutting down the good engine after an engine failure?

                  On one hand, I'll admit that the entirety of the "single vs twin argument" isn't pertinent to this crash since there are no airliners (that I'm aware of) in the ATR-72's class that have only one engine.

                  But on the other hand, mismanagement of power on twin-engine aircraft after an engine failure, which is a big component of the "single vs twin argument", IMHO is a very valid discussion point in the context of this accident.
                  Be alert! America needs more lerts.

                  Eric Law

                  Comment


                  • Originally posted by Evan View Post
                    The final roll before impact was the inevitable wing-stall resulting from a need to clear buildings.
                    What?

                    --- 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


                    • I think what he meant was something that had crossed my mind also: were the pilots put (or think they were put) in a no-win situation?

                      Push forward on the yoke (or release back pressure), keep plane flying and slam into a building, or pull back to see if maybe there's a little more lift hiding in there somewhere to clear the building, but if you're wrong (and you probably are), you crash into something else.
                      Be alert! America needs more lerts.

                      Eric Law

                      Comment


                      • Originally posted by Gabriel View Post
                        What?
                        A collision of black and white thinking with spatial, analogue thinking.

                        A lot of light twin engine failure crashes are loss of control from asymmetric thrust.

                        This crash contrasts with that because the thrust was fairly symmetrical (and close to zero) and the loss of control was most likely the result of a stall which was most likely the result of the guys being very low in altitude and airspeed with big buildings about.

                        Of course not all light twins spin out of asymmetrically powered stall, the ATR may have had some variability in thrust and I haven't seen the Gabriel-style analysis of their glide capability vs. their terrain to know for sure if they might have been better off to crash, under control among buildings...it does seem reasonable that maybe they were managing speed and AOA about as good as can be expected and hoping for a softer splash down (indeed some folks survived).

                        As Elaw eloquently stated- the question of several critical, high-work-load tasks when a twin becomes a single and more than one way to botch things and all sorts of gray area issues including startle factor...

                        ...it can all be part of what happens when a twin-turned-single crashes and are things that are equally relevant to twin vs. single as well as why did this twin-turned-single crash.
                        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                        Comment


                        • Originally posted by elaw View Post
                          I think what he meant was something that had crossed my mind also: were the pilots put (or think they were put) in a no-win situation?

                          Push forward on the yoke (or release back pressure), keep plane flying and slam into a building, or pull back to see if maybe there's a little more lift hiding in there somewhere to clear the building, but if you're wrong (and you probably are), you crash into something else.
                          That's a fallacious dilemma. The plane doesn't glide any better or any farther stalled (or even close to the stall) than non stalled.

                          While it is true that there is some "altitude for speed" to trade between the best glide speed and the stall, that doesn't mean that you need to go all the way to the stall. I fear that nobody in the investigation will make this analysis, but it's quite evident to me that had they not stalled they would have cleared the bridge and crashlanded in the river upright instead of inverted.

                          In the last video the plane is clearly already stalled when flying by that building. And that was a short while before the loss of roll control.

                          Look what the (frozen engines) British Airways 777 pilot did. They were worried about crashing against the ILS LOC antenna. At what point the stickshaker activated. What did the pilot do? Reduce the AoA. They cleared the antenna. Do you think they would have managed to do it had they stalled the 777?

                          --- 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
                            As Elaw eloquently stated- the question of several critical, high-work-load tasks when a twin becomes a single and more than one way to botch things and all sorts of gray area issues including startle factor...

                            ...it can all be part of what happens when a twin-turned-single crashes and are things that are equally relevant to twin vs. single as well as why did this twin-turned-single crash.
                            And I agree with that, just don't say that the stall was unavoidable please (unless you mean that the crew factually was unable to avoid it, not that it could not have possibly been avoided).

                            --- 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 a fallacious dilemma. The plane doesn't glide any better or any farther stalled (or even close to the stall) than non stalled.
                              I will argue with you against relentless pull ups to the point of stall...

                              Edit: I was not clear that "with" meant "in agreement with" or "along with" you...Indeed, "with" is a vague term- with one interpretation being I will argue against you. I did not_mean argue against, I meant argue along with you.

                              After the stall occurs, I'm thinking there's some horrible psychological things going on...

                              Including something very basic.

                              You are walking on ice...do you want to slip nose down and plant your face on the ice or slip back and plant your somewhat padded a$$ on the ice.

                              I'm afraid that the thought of smacking the tail into the ground first instead of the short nose ahead of you might be powerful enough to make you want to haul up all the way after the plane breaks.

                              And, if you are 1" above the treeline in a 172, I sort of want the cabin floor and collapsible seat to cushion the blow and maybe even deflect some limbs, instead of punching them through the window in a more level attitude and relying totally on the shoulder strap to protect you from the panel.

                              It would be unwise to argue aerodynamics with you...but I am a little more forgiving of the relentless pull up when it seems that lift is lost and there's no altitude for recovery.
                              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                              Comment


                              • Originally posted by 3WE View Post
                                I will argue with you ...
                                I won't, and I agree 99% with all that you said.

                                Again, just don't say that they had no choice but to stall to avoid the buildings. Or in Evan's words:

                                The final roll before impact was the inevitable wing-stall resulting from a need to clear buildings.
                                There was another way. It was hard to do. Lot of temptations to pull up + lots of workload + knowing that you are likely about to die are all good reasons to screw up. But it's not like they had no choice but to stall to avoid the buildings.

                                --- 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