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Air France near topmstal disaster

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  • Air France near topmstal disaster

    The clock is topmsing....

    An Air France Airbus A340-300, registration F-GLZU performing flight AF-423 from Bogota (Colombia) to Paris Charles de Gaulle (France) with 275 people on board, departed Bogota's runway 13R (length 3,800 meters/12,470 feet, elevation 2,548 meters/8,360 feet) at 18:56L (23:56Z) and continued to Paris for a safe landing without further incident.

    On Apr 25th 2017 the BEA reported that the aircraft needed an abnormally long takeoff run. The occurrence was rated a serious incident and is being investigated by the BEA having been delegated the investigation by Colombia's GRIAA.

    According to preliminary information the aircraft crossed the runway end at about 5 feet above ground instead of 35 feet AGL.
    The "instead of 35ft" part it is wrong.

    The available take-off distance (TODA) must be equal or greater than the required take-off distance (TOD). In turn, the required take-off distance is the greatest of:
    1- The distance required to accelerate to Vef (the speed at which the critical engine is supposed to fail, about 1 second before V1), have the engine fail at this point, continue the take-off with the remaining engine(s), lift off and reach 35ft and V2 plus margin of a distance equivalent to 2 seconds at V1.2- The distance required to take-off with all the engines operative and reach V2 and 35ft, plus 15% of that distance.

    Since, I assume, and engine didn't fail, the plane should have achieved 35 ft with 15% of the runway still ahead.

    This sounds to me as an inconsistency between the take-off computation data vs the reality vs the execution (flaps setting, weight, wind, thrust setting...)

    --- 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 ---

  • #2
    Originally posted by Gabriel View Post

    This sounds to me as an inconsistency between the take-off computation data vs the reality vs the execution (flaps setting, weight, wind, thrust setting...)

    ...or not positioning from the runway threshold, although at 8300' FE I think a full 343 would need every inch of runway to meet those requirements, and just forget about derated thrust.

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    • #3
      "We" should have the industry all formally adopt the ATL Crew procedure.

      Bobby largely opposed TOPMS as potentially causing more risks due to false warnings.

      Snarkieness aside, these are considerations.

      I seem to recall: ATL milestone + everything = normal = Go.

      If you miss the ATL milestone OR there is something else is amiss, abort.

      If you feel funny, but have no negative indications, BUT YOU ACHEIVE THE ATL milestone, then Go.

      ATL milestone probably happens at a somewhat fast speed, but with a nice buffer before V1.
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

      Comment


      • #4
        Originally posted by 3WE View Post
        "We" should have the industry all formally adopt the ATL Crew procedure.

        Bobby largely opposed TOPMS as potentially causing more risks due to false warnings.

        Snarkieness aside, these are considerations.

        I seem to recall: ATL milestone + everything = normal = Go.

        If you miss the ATL milestone OR there is something else is amiss, abort.

        If you feel funny, but have no negative indications, BUT YOU ACHEIVE THE ATL milestone, then Go.

        ATL milestone probably happens at a somewhat fast speed, but with a nice buffer before V1.
        OK, sorry to be Mr. Thicky here, but can I ask a few questions:

        - What does TOPMS stand for?
        - What does ATL stand for?
        - Who is Bobby?

        Sorry, lots of acronyms flying around and I'm trying to get my head around this!

        Comment


        • #5
          Originally posted by akerosid View Post
          OK, sorry to be Mr. Thicky here, but can I ask a few questions:

          - What does TOPMS stand for?
          - What does ATL stand for?
          - Who is Bobby?

          Sorry, lots of acronyms flying around and I'm trying to get my head around this!
          TOPMS = Take-Off Performance Monitoring System. Basically, a system that checks if the rate at which the airspeed increases is in par with what should be according to the assumptions in the take-off performance computation.

          ATL is Atlanta, and also ATL Crew, a forum member who claims to be a pilot (and we believe him)

          Bobby is BoeingBobby, a Forum member who claims to be a pilot (and we believe him) who opposed to the installation of the TOPMS.

          --- 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


          • #6
            Originally posted by Gabriel View Post
            TOPMS = Take-Off Performance Monitoring System. Basically, a system that checks if the rate at which the airspeed increases is in par with what should be according to the assumptions in the take-off performance computation.

            ATL is Atlanta, and also ATL Crew, a forum member who claims to be a pilot (and we believe him)

            Bobby is BoeingBobby, a Forum member who claims to be a pilot (and we believe him) who opposed to the installation of the TOPMS.
            Gabriel is a forum member that believes TOPMS should be required and starts a thread whenever there's a close call.

            Bobby and ATL have stated that they use a time-speed check as a safety backup. Methods which do not officially exist in the formal FCOM/QRH/POH and related procedural documents.

            3WE is a forum member who likes TOPMS but wonders if Bobby's objections and ATL's silence might indicate a valid concern.

            The forum is a place where industry outsiders discuss and judge how industry insiders should do their jobs from computer keyboards at very low altitudes and speeds relative to nearby hard objects.
            Last edited by 3WE; 2017-04-27, 17:03. Reason: Corrected for incorrect statement, pointed out by elaw.
            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

            Comment


            • #7
              Originally posted by 3WE View Post
              The forum is a place where industry outsiders discuss and judge how industry insiders should do their jobs from computer keyboards at very low altitudes and speeds.
              I'm sorry, sir, but that last bit is not correct. According to this page: http://www.dailymail.co.uk/sciencete...rths-axis.html I am traveling in an Easterly direction at around 750 MPH as I write this!
              Be alert! America needs more lerts.

              Eric Law

              Comment


              • #8
                BOG is an interesting place. Amazing how performance is just not there at 8,000'+.

                Comment


                • #9
                  Originally posted by ATLcrew View Post
                  BOG is an interesting place. Amazing how performance is just not there at 8,000'+.
                  Only the performance in the manuals needs be there. If the manuals say that the plane should have been with 35ft and V2 with 15% of the runway ahead, then it should not have been 5 ft AGL with 0ft of runway ahead. If the manuals say it the plane would not have been at 35ft and V2 with 15% of the runway ahead, then the take off should not have been attempted (it would have been illegal).

                  My guess is that something was amiss. Wight, flaps settings, thrust setting, temp, QNH, wind, elevation, slope, wind...

                  --- 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


                  • #10
                    Originally posted by elaw View Post
                    I'm sorry, sir, but that last bit is not correct. According to this page: http://www.dailymail.co.uk/sciencete...rths-axis.html I am traveling in an Easterly direction at around 750 MPH as I write this!
                    I corrected my post.

                    That said, do we not have to also factor in the speed of the earth around the sun, the speed of the sun, the movement of the swirl of the Milky Way AND the movement of the Milky Way itself versus what? Some proposed fixed, non-moving, intangible 'fabric-substance' called space...

                    I think that some drugs may be needed.
                    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                    Comment


                    • #11
                      Originally posted by Gabriel View Post
                      ***If the manuals say that the plane should have been with 35ft and V2 with 15% of the runway ahead, then it should not have been 5 ft AGL with 0ft of runway ahead....something...amiss. Wight, flaps settings, thrust setting, temp, QNH, wind, elevation, slope, wind...
                      So many variables.

                      So much faith in a book based on scientific engineering.

                      If only someone could make an I-phone app to double check that things are on track...
                      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                      Comment


                      • #12
                        Originally posted by 3WE View Post
                        If only someone could make an I-phone app to double check that things are on track and call it TOPMS...
                        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

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