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Aerosucre B-727 crash

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  • #76
    Originally posted by 3WE View Post
    Yes...but the black and white acronym department doesn’t like relative runway requirement comparisons- the concept confuses them.
    As yes, so very confusing! The common definition of STOL is the ability to go from the start of the take-off roll to V2 (50' above obstacles) in the very black and white distance of 1500ft!

    An empty 727-200ADV can get out of a 4000' runway. That is relatively good short-field perfomance, But at MTOW is needs about 10,000ft. I suspect this one was more in the latter category.

    My point being, the popular myth the the 727 was some sort of STOL-esque passenger jet is a bit misplaced.

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    • #77
      Originally posted by Evan View Post
      As yes, so very confusing! The common definition of STOL is the ability to go from the start of the take-off roll to V2 (50' above obstacles) in the very black and white distance of 1500ft!

      An empty 727-200ADV can get out of a 4000' runway. That is relatively good short-field perfomance, But at MTOW is needs about 10,000ft. I suspect this one was more in the latter category.

      My point being, the popular myth the the 727 was some sort of STOL-esque passenger jet is a bit misplaced.
      Here’s a fun exercise...go see if Schwartz or I ever said, “The 727 was designed to be an official FAA acronym defined STOL aircraft”.

      Per usual, it’s a challenge for you to comprehend that the aircraft might have been designed to operate in a gray area of offering better takeoff performance and runway flexibility than a 707 or DC-8...the flexibility to serve smaller cities with smaller airports (more gray areas for you.)

      Unfortunately the acronym ITPARFVSOSADCE and associated requirements were never developed to allow you to understand some of the design considerations for DC-9 and 727 aircraft.



      I look forward to a video of a 707 or DC-8 operating on gravel...I’m fairly confident that happens less often.
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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      • #78
        Originally posted by 3WE View Post
        Here’s a fun exercise...go see if Schwartz or I ever said, “The 727 was designed to be an official FAA acronym defined STOL aircraft”.

        Per usual, it’s a challenge for you to comprehend that the aircraft might have been designed to operate in a gray area of offering better takeoff performance and runway flexibility than a 707 or DC-8...the flexibility to serve smaller cities with smaller airports (more gray areas for you.)

        Unfortunately the acronym ITPARFVSOSADCE and associated requirements were never developed to allow you to understand some of the design considerations for DC-9 and 727 aircraft.



        I look forward to a video of a 707 or DC-8 operating on gravel...I’m fairly confident that happens less often.
        PS- Are the MTOW performance figures relevant for a 1968 flight from Little Rock to Chicago? There’s that OTHER gray concept of flexibility- fill the tanks, max it out, do the LTOL thing and fly a load of buttocks across a pond.
        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

        Comment


        • #79
          Originally posted by Gabriel View Post
          The flap setting could explain a low climb gradient but should also provide a lower Vr and hence earlier rotation, the plane rotates near the end of the runway what makes me think that the flap setting was not the main issue, and then even when well nose-up it fails to climb what means that it was rotated at a lower speed than required for the weight and confing. This plane was overweight or underpowered for the available take-off distance (TODA). Or both. Flaps setting is secondary.
          They were overweight by two thousand pounds. The nails in the coffin seem to be that the company had them using performance charts for an unmodified 727, which gave them a Vr 7kts higher than necessary, combined with a slow rotation rate of about 1°/sec. The thumbtack in the coffin may have been the 4kt tailwind.

          Once airborne, after mowing down the hut and damaging the main gear, they lost A hydraulics and possibly the B system as well, however the crew did not take action to switch to back-up hydraulics. As a result, the forces needed to control the plane eventually exceeded the crew's ability. It must have been a terrifying experience.

          It is possible that they might have regained control and got it back on the ground if they had taken that action. The flaps asymmetry was apparently not a fatal situation.

          GRIAA report out: http://avherald.com/h?article=4a25fb25&opt=0

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          • #80
            Originally posted by Evan View Post
            They were overweight by two thousand pounds. The nails in the coffin seem to be that the company had them using performance charts for an unmodified 727, which gave them a Vr 7kts higher than necessary, combined with a slow rotation rate of about 1°/sec. The thumbtack in the coffin may have been the 4kt tailwind.

            Once airborne, after mowing down the hut and damaging the main gear, they lost A hydraulics and possibly the B system as well, however the crew did not take action to switch to back-up hydraulics. As a result, the forces needed to control the plane eventually exceeded the crew's ability. It must have been a terrifying experience.

            It is possible that they might have regained control and got it back on the ground if they had taken that action. The flaps asymmetry was apparently not a fatal situation.

            GRIAA report out: http://avherald.com/h?article=4a25fb25&opt=0
            I think the nail in the coffin was the fact they didn't try the backup hydraulics. They had 2 fully working engines. Clearly not a very professional outfit.

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            • #81
              It should be noted that after all of the parlour pontification regarding Gabriel's honed, measured nose-down response, we shamelessly reverse our admonishment to these guys who didn't pull up enough...
              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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              • #82
                Originally posted by 3WE View Post
                It should be noted that after all of the parlour pontification regarding Gabriel's honed, measured nose-down response, we shamelessly reverse our admonishment to these guys who didn't pull up enough...
                Actually it seems to have been roll that did them in and I believe the controls were deflected fully in the opposite direction. Just missing the magic of hydraulics.

                Comment


                • #83
                  Originally posted by 3WE View Post
                  It should be noted that after all of the parlour pontification regarding Gabriel's honed, measured nose-down response, we shamelessly reverse our admonishment to these guys who didn't pull up enough...
                  Oh, you're talking about before the hut...

                  Comment


                  • #84
                    Originally posted by Evan View Post
                    Oh, you're talking about before the hut...
                    Yes.

                    Gabriel made a big deal that with the V1 and engine out buffers, the take off might have suffered more from yoke technique than the weight and tailwind.
                    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                    Comment


                    • #85
                      If you want to discuss not pulling up enough, then AA 191 is a much more interesting example, since the guys had not 1 but 2 stickshaker activations, and not pulling up enough was certainly one cause of the accident. That alone could and would have saved them.

                      --- 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


                      • #86
                        Originally posted by 3WE View Post
                        Yes.

                        Gabriel made a big deal that with the V1 and engine out buffers, the take off might have suffered more from yoke technique than the weight and tailwind.
                        Yes, late and slow rotation seems to be what did the hut in. Probably wouldn't have been a problem if they weren't overweight though, so pick your poison...

                        Comment


                        • #87
                          Originally posted by Gabriel View Post
                          If you want to discuss not pulling up enough, then AA 191 is a much more interesting example, since the guys had not 1 but 2 stickshaker activations, and not pulling up enough was certainly one cause of the accident. That alone could and would have saved them.
                          That's a typo, right?

                          Comment


                          • #88
                            Originally posted by Evan View Post
                            Yes, late and slow rotation seems to be what did the hut in. Probably wouldn't have been a problem if they weren't overweight though, so pick your poison...
                            I made no statement that this dismissed other contributing factors- and yes, this is textbook "chain of events" and I would hesitate to assign one factor as being primary.

                            I just wanted to point out the contrast of how quickly Gabe will turn the table and trash pilots who try to avoid relentless pull ups- such as AA-191.

                            Acknowledging that it's not simply about the pull up, the word "measured" is pretty significant as well as some good, quick, and appropriate problem solving ability and actions for when you hear a stall warning.
                            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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                            • #89
                              Originally posted by 3WE View Post
                              ...such as AA-191.
                              Did I accidentally log in to an alternate universe?

                              Comment


                              • #90
                                Originally posted by Evan View Post
                                That's a typo, right?
                                I don't know. Which part?

                                --- 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

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