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AB B738 runway overrun after rejected take off

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  • AB B738 runway overrun after rejected take off

    German link:

    http://nachrichten.t-online.de/dortm...21218970/index

    http://www.stern.de/reise/wetter/lex...n-1533028.html

    No fatalities - thank god. Flight was bound to TFS with 166 people on board.

    wilco737

  • #2
    Vaguely understand it. Can't find a translation for
    Geschwindigkeitsanzeigen

    Comment


    • #3
      Originally posted by EconomyClass View Post
      Vaguely understand it. Can't find a translation for
      Geschwindigkeitsanzeigen
      Geschwindigkeitsanzeigen: Air speed indicator. It is said that they showed differently on CP and FO side, hence the rejected take off.

      wilco737

      Comment


      • #4
        Originally posted by WILCO737 View Post
        Geschwindigkeitsanzeigen: Air speed indicator. It is said that they showed differently on CP and FO side, hence the rejected take off.

        wilco737
        If I may ask, at your airline and on your airplane, is airspeed disagreement something worthy of a high-energy abort?

        Comment


        • #5
          Originally posted by Curtis Malone View Post
          If I may ask, at your airline and on your airplane, is airspeed disagreement something worthy of a high-energy abort?
          It is a question which you cannot really answer with a yes or no. The problem is of course if you go airborne in IFR conditions, how to confirm which air speed indicator is showing the correct speed and which isn't... This cannot always be solved within 2 seconds. The thought of the captain could've been that the pitot tubes (used for the airspeed) maybe totally iced and clogged and maybe none of the air speed indicators shows correct information.
          I don't know at what speed the take off was aborted, but our high- energy take off starts at 80 knots and many alerts are inhibited by the airplane (MD11), at the B738 they are not. I think that the captain thought it is the safer course of action to stop on the runway and evaluate the error than taking this very difficult error into the air.
          Why the airplane overrun is not clear yet. Air Berlin says that DTM airport didn't de- ice the runway properly.
          We will see what the investigation will bring.

          I hope that helps.

          wilco737

          Comment


          • #6
            Originally posted by WILCO737 View Post
            It is a question which you cannot really answer with a yes or no. The problem is of course if you go airborne in IFR conditions, how to confirm which air speed indicator is showing the correct speed and which isn't... This cannot always be solved within 2 seconds. The thought of the captain could've been that the pitot tubes (used for the airspeed) maybe totally iced and clogged and maybe none of the air speed indicators shows correct information.

            I don't know at what speed the take off was aborted, but our high- energy take off starts at 80 knots and many alerts are inhibited by the airplane (MD11), at the B738 they are not. I think that the captain thought it is the safer course of action to stop on the runway and evaluate the error than taking this very difficult error into the air.
            I agree, I was just curious what your procedure was. For us high-energy starts at 100kts, and I personally had a situation when we had an ASI disagreement at 120kts or so. The takeoff was continued and the ASIs subsequently came into agreement. Granted, it was perfect VFR.

            What I'd be curious to know about this case is at what speed they noticed the disagreement, how big the disagreement was, whether or not they got a chance to look at the standby ASI and whether or not it agreed with either primary ASI and finally at what speed the abort was made.

            Comment


            • #7
              heres a pic of it
              click it to make it bigger




              click it to make it bigger
              Theres strong, then theres Army Strong!
              www.goarmy.com

              Comment


              • #8
                In pic #3 from stern.de, it looks like the flaps are at landing position or close to it, they're quite a bit past TO position anyway. Why might that be, I wonder?

                Comment


                • #9
                  i just wonder:

                  a.) usually, after V1 is reached, the aircraft must take-off because otherwise the remaining length of the runway would not be sufficient to stop the a/c on time. since V1 is calculated depending on data such as as take off weight an weather this leads to the question if

                  1.) the take-off was rejected after reaching V1
                  2.) the take-off was rejected before reaching V1 but either the runway breaking conditions did not collerate with the calculated data or
                  3.) not all available breaking devices were or could be used

                  According to the pictures published, I could not see the thurst reveres deployed nor did I see the speed breakes extended.

                  in an german TV interview a passenger was quoted that the fron gear lift off before the TO was rejected.


                  let's wait an see what the investigations will come up with.
                  Ciao,
                  Jason

                  Comment


                  • #10
                    [photoid=6745451]
                    [photoid=6745261]
                    Curtis, from the B737-800 QRH:
                    Condition: Evacuation is needed.
                    Parking brake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Set
                    Speedbrake lever. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DOWN
                    [Prevents possible interference or injury to passengers evacuating
                    through the overwing escape hatches.]
                    FLAP lever. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
                    [Aids in evacuating passengers over the wing.]
                    I would suggest they were considering the possibility of an evacuation.
                    Last edited by AJ; 2010-01-03, 23:02.

                    Comment


                    • #11
                      perhaps a bit off-topic, but i'm curious...since the a/c appears to be intact, how do they tow it back? the usual a/c tractors don't appear to be well suited for off-road use.

                      Comment


                      • #12
                        Originally posted by Jason View Post
                        usually, after V1 is reached, the aircraft must take-off because otherwise the remaining length of the runway would not be sufficient to stop the a/c on time.
                        Not necesarily true (and many times not true).
                        I don't know in this case.

                        --- 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


                        • #13
                          Originally posted by Gabriel View Post
                          Not necesarily true (and many times not true).
                          I don't know in this case.

                          if this is not necessarily true, what would be the purpose of (exclaiming) V1?
                          Ciao,
                          Jason

                          Comment


                          • #14
                            V1 is treated as the decision speed. For failures before V1, the crew stop, for failures above V1 (where the aircraft will fly) they continue.

                            That said - V1 for any given takeoff can often be varied. I'll give you a fairly basic overview of why... it can be much more complex than this.

                            Basically, the decision speed must achieve two things. 1 - At this speed you must be able to stop on the remaining runway, and 2 - At this speed you must be able to have a failure of the (critical) engine (in this case either engine), and be able to accelerate and take off, clearing the end of the runway by a given margin (depending on conditions).

                            Overview - you must be able to stop, and you must be able to continue. Unless the takeoff is particularly limiting (such as high terrain near the end of the runway, or a particularly short runway surface), the aircraft will often reach a speed where the takeoff can be continued quite early in the takeoff run (the "go" case)... and can accelerate to a speed far higher than this before it runs out of runway for the "stop" case.

                            In this situation, V1 could theoretically be selected anywhere between the minimum for continuing (go), and the maximum for stopping (stop).

                            An additional complication for this is that quite often the aircraft will in fact reach its "rotate" (takeoff) speed before it has run out of room to stop. In this case, the aircraft is not stop case limited at all... as the aircraft will be airborne before it has run out of runway to stop.

                            Depending on the aircraft type, runway length, weight and terrain, accompanied by the country of certification and the airline policy, a V1 is selected - and quite often it is based on the minimum speed at which the aircraft can continue the takeoff with the loss of one engine. Quite often, this means that the aircraft is not limited with regarding a rejected takeoff. So the call of "V1" is a call that "for any problem we will continue the takeoff"... but it does not always mean that there would be insufficient runway to stop.

                            Thats just a general overview as to why Gabriel has made the statement he has - I do not know the limiting features of the takeoff on the accident flight.

                            Comment


                            • #15
                              Originally posted by MCM View Post
                              Depending on the aircraft type, runway length, weight and terrain, accompanied by the country of certification and the airline policy, a V1 is selected - and quite often it is based on the minimum speed at which the aircraft can continue the takeoff with the loss of one engine.
                              would this not rather be described as V2?


                              Originally posted by MCM View Post
                              So the call of "V1" is a call that "for any problem we will continue the takeoff"... but it does not always mean that there would be insufficient runway to stop
                              .


                              Originally posted by Jason View Post
                              a.) usually, after V1 is reached, the aircraft must take-off because otherwise the remaining length of the runway would not be sufficient to stop the a/c on time.


                              Originally posted by MCM View Post
                              Thats just a general overview as to why Gabriel has made the statement he has - I do not know the limiting features of the takeoff on the accident flight.
                              thanks for clarifying the matter with the remainung runway
                              Ciao,
                              Jason

                              Comment

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