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We have analysed the raw data from the transponder of #4U9525 and found some more dat

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  • We have analysed the raw data from the transponder of #4U9525 and found some more dat

    We have analysed the raw data from the transponder of #4U9525 and found some more data apart from the regular position/altitude data.
    These are the decoded ModeS (Downlink Format 20) frames which contain replies to interrogating radar requests (Upling Format 20).

    09:30:48Z.651 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
    09:30:48Z.936 T,3c6618,43.115341,5.671181,38000,GWI18G
    09:30:49Z.496 T,3c6618,43.116028,5.671692,38000,GWI18G
    09:30:50Z.076 T,3c6618,43.117381,5.673065,38000,GWI18G
    09:30:50Z.111 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
    09:30:50Z.553 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
    09:30:50Z.619 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
    09:30:50Z.626 T,3c6618,43.118408,5.673736,38000,GWI18G
    09:30:51Z.127 T,3c6618,43.119095,5.674247,38000,GWI18G
    09:30:51Z.636 T,3c6618,43.120453,5.675092,38000,GWI18G
    09:30:52Z.386 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
    09:30:52Z.567 T,3c6618,43.122208,5.676482,38000,GWI18G
    09:30:53Z.036 T,3c6618,43.122894,5.676993,38000,GWI18G
    09:30:53Z.546 T,3c6618,43.124271,5.678166,38000,GWI18G
    09:30:54Z.083 MCP/FMC ALT: 13008 ft QNH: 1006.0 hPa
    09:30:54Z.096 T,3c6618,43.125295,5.678689,38000,GWI18G
    09:30:54Z.676 T,3c6618,43.125961,5.679421,38000,GWI18G
    09:30:55Z.156 T,3c6618,43.127157,5.680259,38000,GWI18G
    09:30:55Z.397 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:30:55Z.453 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:30:55Z.636 T,3c6618,43.128367,5.681109,38025,GWI18G
    09:30:56Z.186 T,3c6618,43.129211,5.681656,38025,GWI18G
    09:30:56Z.707 T,3c6618,43.129898,5.682167,38000,GWI18G
    09:30:57Z.267 T,3c6618,43.131626,5.683201,38000,GWI18G
    09:30:57Z.312 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:30:57Z.836 T,3c6618,43.132507,5.684020,38000,GWI18G
    09:30:58Z.050 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:30:58Z.296 T,3c6618,43.133011,5.684403,38000,GWI18G
    09:30:58Z.767 T,3c6618,43.134559,5.685425,38000,GWI18G
    09:30:59Z.216 T,3c6618,43.135397,5.685948,38000,GWI18G
    09:30:59Z.746 T,3c6618,43.136261,5.686575,38000,GWI18G
    09:30:59Z.988 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:00Z.146 T,3c6618,43.137451,5.687149,38000,GWI18G
    09:31:00Z.165 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:00Z.676 T,3c6618,43.137817,5.687660,38000,GWI18G
    09:31:01Z.676 T,3c6618,43.139866,5.689022,38000,GWI18G
    09:31:02Z.027 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:02Z.238 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:02Z.496 T,3c6618,43.141402,5.690199,38000,GWI18G
    09:31:03Z.030 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:03Z.456 T,3c6618,43.143494,5.691429,38000,GWI18G
    09:31:04Z.376 T,3c6618,43.145731,5.692945,37975,GWI18G
    09:31:04Z.943 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:05Z.346 T,3c6618,43.147430,5.693984,37975,GWI18G
    09:31:05Z.558 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:05Z.993 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:06Z.466 T,3c6618,43.149828,5.695365,37975,GWI18G
    09:31:07Z.164 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:07Z.346 T,3c6618,43.151367,5.696539,37950,GWI18G
    09:31:08Z.256 T,3c6618,43.153427,5.697752,37950,GWI18G
    09:31:08Z.776 T,3c6618,43.154111,5.698308,37925,GWI18G
    09:31:09Z.276 T,3c6618,43.154995,5.698962,37925,GWI18G
    09:31:09Z.712 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:09Z.960 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:10Z.326 T,3c6618,43.157364,5.700307,37925,GWI18G
    09:31:11Z.312 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:11Z.467 T,3c6618,43.159607,5.701713,37900,GWI18G
    09:31:11Z.876 T,3c6618,43.160660,5.702415,37900,GWI18G
    09:31:12Z.102 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:12Z.386 T,3c6618,43.161512,5.702885,37875,GWI18G
    09:31:12Z.846 T,3c6618,43.162211,5.703408,37875,GWI18G
    09:31:13Z.316 T,3c6618,43.163049,5.704128,37875,GWI18G
    09:31:13Z.896 T,3c6618,43.164597,5.704970,37875,GWI18G
    09:31:14Z.401 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:14Z.493 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:15Z.536 T,3c6618,43.168030,5.707201,37825,GWI18G
    09:31:16Z.416 T,3c6618,43.169380,5.707921,37825,GWI18G
    09:31:17Z.028 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:17Z.266 T,3c6618,43.171288,5.709294,37800,GWI18G
    09:31:18Z.196 T,3c6618,43.173019,5.710144,37775,GWI18G
    09:31:19Z.166 T,3c6618,43.175385,5.711648,37750,GWI18G
    09:31:19Z.262 MCP/FMC ALT: 96 ft QNH: 1006.0 hPa
    09:31:20Z.176 T,3c6618,43.177277,5.712891,37725,GWI18G
    09:31:21Z.216 T,3c6618,43.179202,5.714068,37700,GWI18G

    Between 09:30:52 and 09:30:55 we can see that the autopilot was manually changed from 38,000 feet to 100 feet and 9 seconds later the aircraft started to descend, probably with the "open descent" autopilot setting.
    The reason why the selected altitude is 96ft is that least significant bit for altitude setting equals 16 ft, and we suspect that you can’t set autopilot to 0000 altitude, so the minimum would be 100ft down rounded to 96ft in binary representation in BDS40h register.
    Any comments or thoughts about this?

    Playback: http://www.flightradar24.com/data/fl...u9525/#5d42675

    This data has also been handled over to BEA 2 days ago.

  • #2
    Do you have a link to any resources that gives info on how Autopilot setting can be derived from transponder data? *there is some discussion on another forum whether this is actually possible.? Thanks for the post btw

    Comment


    • #3
      Will you someday diplay the selected flight level on the "web radar" as you already have it in your database?

      Comment


      • #4
        Originally posted by dancake View Post
        Do you have a link to any resources that gives info on how Autopilot setting can be derived from transponder data? *there is some discussion on another forum whether this is actually possible.? Thanks for the post btw
        http://www.flightradar24.com/dvbt-stick

        http://www.rtl-sdr.com/adsb-aircraft...-with-rtl-sdr/

        http://se.mathworks.com/help/support...th-matlab.html

        http://www.rtl-sdr.com/modesdeco-now...ode-s-mode-ac/
        Last edited by angelsevov; 2015-03-26, 14:01. Reason: mac os x application

        Comment


        • #5
          to re-phrase. Do you have a link that comfirms autopilot data is transmitted within the transponder data, or do we just have to assume the autopilot was reprogrammed?

          Comment


          • #6
            As far as I understand autopilot data is not transmitted automatically but can be requested from ground stations (ATC). The data can be picked up by anyone, the issue is to understand the data as you don't know what it means if you don't have the up-link request.

            Comment


            • #7
              Originally posted by Mike View Post
              As far as I understand autopilot data is not transmitted automatically but can be requested from ground stations (ATC). The data can be picked up by anyone, the issue is to understand the data as you don't know what it means if you don't have the up-link request.
              ok thanks that makes sense. Is it possible that a request was sent to get data from the FMC because there was no response from the cockpit?

              Comment


              • #8
                Originally posted by dancake View Post
                ok thanks that makes sense. Is it possible that a request was sent to get data from the FMC because there was no response from the cockpit?
                This is still being implemented at ATC so I guess different areas can request different data or nothing at all. In this case we had the data during climb as well

                09:18:30Z.455 MCP/FMC ALT: 30000 ft QNH: 1006.0 hPa
                09:21:08Z.800 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:09Z.258 T,3c6618,42.194204,4.553450,32050,GWI18G
                09:21:10Z.208 T,3c6618,42.195923,4.555518,32050,GWI18G
                09:21:11Z.109 T,3c6618,42.197296,4.557079,32075,GWI18G
                09:21:11Z.897 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:12Z.169 T,3c6618,42.199493,4.559638,32100,GWI18G
                09:21:35Z.518 T,3c6618,42.238312,4.606330,32500,GWI18G
                09:21:38Z.418 T,3c6618,42.243130,4.612342,32550,GWI18G
                09:21:38Z.951 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:39Z.268 T,3c6618,42.244852,4.614386,32550,GWI18G
                09:21:40Z.198 T,3c6618,42.246185,4.615943,32575,GWI18G
                09:21:40Z.623 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:41Z.138 T,3c6618,42.247742,4.618003,32600,GWI18G
                09:21:41Z.325 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:42Z.068 T,3c6618,42.249135,4.619559,32600,GWI18G
                09:21:42Z.897 T,3c6618,42.250858,4.621603,32625,GWI18G
                09:21:42Z.901 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:43Z.957 T,3c6618,42.252533,4.623647,32650,GWI18G
                09:21:44Z.948 T,3c6618,42.254425,4.626056,32675,GWI18G
                09:21:45Z.215 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:45Z.413 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:46Z.864 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:46Z.877 T,3c6618,42.257375,4.629715,32700,GWI18G
                09:21:47Z.738 T,3c6618,42.258585,4.631057,32725,GWI18G
                09:21:48Z.618 T,3c6618,42.260468,4.633297,32725,GWI18G
                09:21:49Z.748 T,3c6618,42.262161,4.635544,32750,GWI18G
                09:21:50Z.212 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                09:21:50Z.463 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa

                Comment


                • #9
                  electronic malfunction should be considered too..we can't solely put the blame to the dead pilots...

                  Comment


                  • #10
                    Originally posted by kucengemok View Post
                    electronic malfunction should be considered too..we can't solely put the blame to the dead pilots...
                    Oh i think we can, the co pilot was a mass murderer.
                    FR24 Feeder Station F-CYFC1.

                    Comment


                    • #11
                      the problem with the DF20 is that you dont know what the ATC was asking for in the UF20.
                      usually you get some replies back you cannot interpret. there are some 100 registers which can be asked for.
                      Its a bit like ACARS where it is hard to interpret what you receive.
                      http://www.liveatc.net/search/?icao=LSGG

                      Comment


                      • #12
                        Originally posted by Mike View Post
                        This is still being implemented at ATC so I guess different areas can request different data or nothing at all. In this case we had the data during climb as well

                        09:18:30Z.455 MCP/FMC ALT: 30000 ft QNH: 1006.0 hPa
                        09:21:08Z.800 MCP/FMC ALT: 38000 ft QNH: 1006.0 hPa
                        Mike, isnīt the 1006 QNH strange though? Or am I naive in assuming that it should be 1013 when at that kind of level.

                        Comment


                        • #13
                          1006 was the pressure at BCN, so for some reason it remained in the data/signal.

                          Comment


                          • #14
                            Originally posted by pitsie View Post
                            Mike, isnīt the 1006 QNH strange though? Or am I naive in assuming that it should be 1013 when at that kind of level.
                            No, that would be QNE, QNH will give you your true height above sea level and should be set to the actual barometric pressure at sea level, QNE is the international standard for defining flight levels and would be what an aircraft would be using on a defined flightpath, for determining such things as terrain clearance QNH should be used.
                            Ben.

                            QFE = pressure setting to read zero feet at your departure/arrival (runway)
                            QNH = pressure setting to read altitude above sea level
                            QNE = 'universal' setting for flight levels (1013.25)

                            Additionally there would be no reason to include QNE in a data report as it is a fixed value.
                            Last edited by F-EGLF1; 2015-03-26, 20:09. Reason: Added altimeter settings
                            FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

                            Comment


                            • #15
                              OK thanks! So as Mike says, the QNH it reports is just whatever was last entered (at BCN in this case).

                              Comment

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