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Malaysia Airlines Loses Contact With 777 en Route to Beijing

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  • Originally posted by Evan View Post
    Reported or rumoured?
    Media reports that sound authentic (most media reports I've dismissed).

    Is this "turn" the same as the WP change at 1:07 in Post 890 above?

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    • Originally posted by Highkeas View Post
      What does the 40 degree line refer to? Certainly not latitude or longitude.
      I believe this refers to the conical angle of the transmission from the transmitter to the satellite. This is how the distance arc is determined, so the last transmission was coming from the 40° arc. (see Gabriel's post a bit further back in this thread).

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      • Originally posted by BoeingBobby View Post
        No one said that you turn off the transponder if there is a fire. What was said was, you turn off the transponder if is the source of the fire.
        Spoon-feeding, uh?

        --- 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 ---

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        • Originally posted by Evan View Post
          I believe this refers to the conical angle of the transmission from the transmitter to the satellite. This is how the distance arc is determined, so the last transmission was coming from the 40° arc. (see Gabriel's post a bit further back in this thread).
          That would make the arc radius 8,093 miles assuming the included cone angle is 40 degrees. In other words the coverage would be twice the diameter of the earth (which I doubt). I would like to learn exactly how this arc is constructed.

          Comment


          • Originally posted by Highkeas View Post
            What does the 40 degree line refer to? Certainly not latitude or longitude.
            40° is the elevation angle of the a line that goes from the airplane to the satellite.

            Since this specific satellite is geostationary (i.e. it is always over the same point of the Earth surface, or in always in the same coordinates if you will) this 40° line will form a cone with vertex in the satellite. The intersection between that 40° cone and the surface of the Earth is a circle, the now famous "arcs" or "corridors" that show the possible positions of the airplane when it last contacted the satellite. This arc is the 40° arc. The fact (fact?) the plane's two last reported pings were on the 40° line means that it was on the same arc at both times. That doesn't mean that the plane was in the same place. It could be the same point (which obviously will be the same line) but it could also be 2 different points on the same line. It could even mean "the same point in both pings but after passing through other points between pings" (returning to the point of the first ping). That's why I said that "compatible" (but not evidence) that the plane was on the ground (i.e. not moving). But conversely, if the last two pings were not in both the same arc that would prove that the plane was not in the same position, hence moving at least during some time between both pings.

            --- 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 ---

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            • Originally posted by B757300 View Post
              The media says "reported" but I've been wondering how anyone could know that. How could anyone tell from the radar data that the aircraft was turning on autopilot rather than by manual control?
              It would come from the first item in the timeline posted above:

              1:07 - ACARS last transmission (thru VHF) which apparently includes notation of a WP change having been entered into system since last scheduled report at 12:37
              The ACARS apparently was set to send reports every hour. In the 12:37 report it reported that a new WayPoint (WP) had been entered in the FMS (Flight Management System) since last report.

              It doesn't say if what WP it was is part of the ACARS report or not, but if the route was (invented waypoint codes ABC - RSQ - XYZ (imagine that RSQ was the point of hand over between Malaysian and Vietnamese airspaces and ATC) between ABC and RSQ you receive the information "new waypoint entered" and when the plane reaches RSQ the pilot replays 'Alright, Good Night' at handover and then simultaneously the transponder is lost, radio comm is lost, and the plane turns away from XYZ and instead heads to IJK, the suspicion that IJK was the waypoint entered in the FMS is strong.

              --- 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 ---

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              • Originally posted by Evan View Post
                This "report" would suggest that this flight plan was predefined and sent from a co-conspirator and would be visible to both pilots before takeoff
                What report? Where?

                --- 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 Highkeas View Post
                  That would make the arc radius 8,093 miles assuming the included cone angle is 40 degrees.
                  Can you please explain how you get to that number? (honest question)

                  In other words the coverage would be twice the diameter of the earth
                  Since the arc is the intersection between the cone and the Earth, getting a radius larger than the Earth is impossible because then both surfaces would not intersect. Hence the previous question.

                  --- 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 ---

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                  • Originally posted by Gabriel View Post
                    What report? Where?
                    The alleged report Highkeas is referring to. I have no idea where that is coming from or if it is anything more than another rumour. It's getting rich out there...

                    Comment


                    • Originally posted by Highkeas View Post
                      I would like to learn exactly how this arc is constructed.
                      I don't know really, but this is what I have in mind. The thick red line would be the arc and the 40° angle would be one of those two marked with thin red.


                      --- 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


                      • The smouldering fire theory certainly got some air time today, despite its lack of plausibility in light of the evidence we have.

                        I also noticed that several pilots were actually the ones talking about this theory as though it were some sort of realistic explanation (also summarily dismissed by other pilots, I might add).

                        But then I thought about why this might be. If, as seems altogether possible, this aircraft is never found, then what better protection for pilots than to have planted this seed of an idea in the minds of the public that it wasn't the machinations of a crew member, but rather some insidious mechanical problem that made the 777 vanish into thin air. Looking out for their own.

                        Comment


                        • Originally posted by Evan View Post
                          The alleged report Highkeas is referring to. I have no idea where that is coming from or if it is anything more than another rumour. It's getting rich out there...
                          I don't know what you are talking about. Highkeas said this:

                          It is now being reported that the turn back towards Maylasia was programed in to the "autopilot" before the pilots left the Malaysia ATC. This update to the flight plan was sent via ACARS about 12 minutes before the sign-off.
                          And I think it refers to the waypoint added in the FMS between the two ACARS reports (reported in the second ACARS report) as shown in the first item in the timeline (which I don't know if it's true). That would be "manually entered by the pilot in the FMS while in-flihgt, before the handover and turn" much more likely than "predefined and sent from a co-conspirator and would be visible to both pilots before takeoff".

                          --- 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
                            I don't know really, but this is what I have in mind. The thick red line would be the arc and the 40° angle would be one of those two marked with thin red.

                            Ok, that makes sense even to me. Amazing what a blank-faced smiley wearing a dunce cap can teach us.

                            Comment


                            • Originally posted by Evan View Post
                              The alleged report Highkeas is referring to. I have no idea where that is coming from or if it is anything more than another rumour. It's getting rich out there...
                              First reported by MSNBC.

                              'Unnamed US sources' - same sources who gave info regarding the Inmarsat "pings"

                              According to the source, the input into the flight computer occurred at (BUT NOT BEFORE) 1:07 MYT
                              AirDisaster.com Forum Member 2004-2008

                              Originally posted by orangehuggy
                              the most dangerous part of a flight is not the take off or landing anymore, its when a flight crew member goes to the toilet

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                              • Originally posted by Gabriel View Post
                                I don't know what you are talking about.
                                Highkeas is referring to a 'report' (no source given despite my requests) that this altered flight plan was received via ACARS before the flight departed. I think that means the new flight plan would appear in the FMS. Either pilot would have access to that. And of course, someone had to send that new flight plan. From where and why? Like I said, I'm not putting any credence into this 'report' at this time.

                                One of the functions of ACARS is to receive updated flight plans and forward them to the FMS:

                                Flight management system interface

                                In addition to detecting events on the aircraft and sending messages automatically to the ground, initial systems were expanded to support new interfaces with other on-board avionics. During the late 1980s and early 1990s, a datalink interface was introduced between the ACARS management units and flight management systems. This interface enables flight plans and weather information to be sent from the ground to the ACARS management unit, for forwarding to the flight management system. This feature gives the airline the capability to update flight management systems while in flight, and allows the flight crew to evaluate new weather conditions or alternative flight plans.

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