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Thread: Malaysia Airlines Flight Goes Missing En Route to China - Flight MH370

  1. #841
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    Quote Originally Posted by smay69 View Post
    I realised I could test this by just playing back that night, filtering by registration (on this site the registration field quotes the ID but also a 24 bit address, so I assume the ADS-B info includes the 24 bit address and this site has a mapping to the registration ID) and watching to see if it re-emerged anywhere after it disappeared based on the 24 bit address. It didn't. There were rumblings of Squawk code swapping, but the 24 bit address wouldn't change. Does this site get the ICAO addressees based on the ADS-B data directly, or is that somehow looked up based on Squawk code? I can't imagine the Squawk could actually be trusted for anything.
    This site receives the ICAO code directly. In fact this code is the only way to discriminate between packets received. The aircraft registration is not transmitted in ADS-B or Mode S (although it is sometimes entered in as the flight number / call sign). The flight number / call sign is transmitted in ADS-B.

    On this site the ICAO code is referred to as "Hex".

  2. #842
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    Ok. For the technically inclined I found the SITA paper describing (unfortunately not as detailed as I would like) the ACARS to INMARSAT satellite link.

    https://www.google.com/url?sa=t&rct=...62922401,d.bmk

    An excerpt:

    "The ACARS system was expanded to use the Aeronautical Mobile Satellite System (AMSS)..... to use the INMARSAT AMSS service an aircraft must be equipped with a Satellite Data Unit (SDU).......The AECC Characteristic 741 for the Satellite Data Unit specifies the use of an X.25 based protocol...."

    At the risk of giving away my age, I used to log on to the Source and CompuServe via X.25 networks Tymnet and Telenet using my trusty old Apple II back in the day when I was in college. All I can say that the airlines really need to upgrade their technology. The paper does talk about their TCP/IP offering etc but the older aircraft need to be retrofitted.

  3. #843
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    Quote Originally Posted by MIT EE View Post
    Agreed! The Malaysians are completely unreliable. Wish INMARSAT would realize the info directly.
    I can't really blame Inmarsat for keeping a low profile during all this. Operating a satellite service on that scale is massively expensive, and they need to keep the trust of all of their high paying customers. They can't afford to have their name associated with the circus that the Malaysian government is running.

    The other side of the coin is the news media, who have proved to be equally stupid in their mishandling of the story. Most treat those circle segments as if they were the route that the plane took. One TV commentator decided to move the red arcs into completely different positions, just to suit his whimsy! Even if the reliable sources released good data, the news people would butcher the facts so badly...that nobody dares to speak up, it seems.

    Anyway, the one thing about all this that I know for certain is that we, the public don't have enough information to draw any concrete conclusions. We can make educated guesses, nothing more. I can only hope and pray that the real search parties are bringing their A games to the search.

  4. #844
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    Don't believe everything you hear from the media. Treat it as speculation/rumour.

  5. #845
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    John Young, general manager for the Australian Maritime Safety Authority (AMSA), said at a press conference in Canberra yesterday that an extended analysis of consecutive "pings" from the MH370 had been made in order to produce a better estimate of the aircraft's flight path.

    Further more, he asserted that the updated flight path estimate could be mirrored at the equator, to show a corresponding possible northern route, based om the same data.

    (See: http://www.youtube.com/watch?v=2_O9gUgWV6U&t=8m51s)

    I've thus made a (quick-n-dirty) graphic estimate of what that refined northern corridor would look like (click on the image for a larger version).

    As you can see, the new path is a bit different than what has been posted earlier (i.e. the arc based only on the last received "ping").

    From the Bay of Bengal, the path roughly follows the border of India and Bangladesh, continues north in between Nepal and Bhutan (still over a part of India), crosses a 2,000-some kilometer part of western China, and ends in the north-west region of China, in the areas bordering to Kazakhstan.


  6. #846
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    Quote Originally Posted by Oblivian View Post
    Regarding ping vs ping vs ping.

    They shouldn't have adopted the term. But that's the media for you. They have likely done so in the fact that no-one would understand 'heartbeat' or 'keepalive' transmission. The term is likely taken to attempt to portray this, and combined with what most people can relate to - Sonar. Where the transmission sent out and received on reflection is called... a ping

    So, if most hear ping.. its the more common term the brain then associates to 'something was sent out or replied to from proving its existence'
    You might recall that on the first day the press was so wanting there to be a tragic scene for them to cover that they were laser-focused on the ultrasonic "pingers" on the CVR and FDR so that they can be found by sonar. They kept asking why the satellites couldn't find the "pings"... /facepalm

  7. #847
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    Quote Originally Posted by mckinley View Post
    * Can they be disabled by the pilot or another person onboard the airplane?
    Highly doubtful while in flight.

    * Are they reliable? Have there been cases where they failed to deploy or activate after a crash into water?
    No! They are not reliable! I mean, they are as reliable as humanly possible, but the mechanical forces of crash landing destroys these devices quite often. (It's hard to build an antenna that both survives extreme forces and works well.) They're only really useful for relatively soft crash landings (or ditchings).

    Note that only 406MHz EPIRB beacons can be found by satellite. ELT beacons on 121.5MHz and 243.0MHz GUARD frequencies have a very limited range. All would have run out of battery power by now.

  8. #848
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    I'm new to this forum, so forgive me if this has been discussed already:

    Firstly, I wish to thank everyone on this forum, as it is the only place I found where this matter is properly analyzed and discussed. That's why I've registered.

    Secondly, I cannot believe that no other country's military radar picked this up. Not in this modern world. It's been reported here in Australia about the Malaysian military noting the change of direction. But Aus media is not being very accurate and tend to be a little sensationalist for my liking.
    It is my contention that there is some big cover up going on. I dont know why that would be.

    Thanks.
    Last edited by PM2014; 2014-03-20 at 02:56.

  9. #849
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    Quote Originally Posted by MIT EE View Post
    At the risk of giving away my age, I used to log on to the Source and CompuServe via X.25 networks Tymnet and Telenet using my trusty old Apple II back in the day when I was in college. All I can say that the airlines really need to upgrade their technology. The paper does talk about their TCP/IP offering etc but the older aircraft need to be retrofitted.
    LOL...when I was in college we used terminals in the basement to connect to VAX hosts running AT&T UNIX (w/BSD extensions, of course), and from there we connected to other hosts. I can't remember what the network was called back then, but it was an early version of the Internet. I had an Apple II back then too.

    I've worked at places with X.25 and Frame Relay WAN hookups. I gladly left that to the networking people! Before DSL became widespread, I had ISDN at home, and could connect to work via a blazing 128kbps 2xBRI connection. My dial-up ISP allowed a single BRI at no extra charge, but charged a lot for a 2xBRI bonded channel. Those were the days...

  10. #850
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    Question Time in the House of Representatives, PM Tony Abbott announced that credible information has been received by AMSA of two objects located, could be linked to MH370. RAAF Orion has been diverted to locate the objects. (Source: Question Time on SkyNews and ABC)

    http://mobile.abc.net.au/news/2014-0...-mh370/5334314
    Last edited by YSWG; 2014-03-20 at 03:21. Reason: add link

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