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

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  • This explanation given by Tim Farrar is easy to understand. It seems that ACARS is a reporting software utility. It probably went offline at the same time as the ADS-B for whatever reason. But the actual transmitter device was still functioning and responding to the Inmarsat hourly pings for a considerable time.

    http://www.themalaysianinsider.com/s...ngs-tim-farrar

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    • Originally posted by xlynx View Post
      1) How can they be certain ACARS was switched off and did not fail (systematic failures of various systems indicative of a fire for example)?
      The only way to be certain is to examine the hardware for failure.

      Does ACARS send a disconnect signal to indicate a graceful shutdown?
      That would vary widely between different makes and models of ACARS hardware.

      2) Does the ADS-B system rely on ACARS, or has ADS-B been disabled separately?
      ADS-B is a transponder function; it has nothing to do with ACARS.

      3) Can anyone explain why official sources seem to be ignoring ADS-B data? Is it because it can't be verified as authentic and originating from the aircraft?
      The "official sources" which is the Malaysian government says that there was no transponder data after it stopped. That may or may not be true, but without other substantive evidence to contradict their claim, we have no proof that they're ignoring anything.

      4) How would they have calculated the two flight corridors from the ACARS keep-alive data?
      What two flight corridors? Please define "flight corridor".

      Would it be measuring the latency from the aircraft to Inmarsat satellite based on a time stamp?
      That would require extremely accurate and coordinated clocks on both ends. AFAIK neither the Inmarsat satellites nor the plane's satcom radio have such a costly facility.

      Has this method of positioning been tested before? I wonder about inaccuracy due to tiny differences in clock setting, and latency introduced during signal processing at each end.
      That's basically how the GPS, Magellan and GLONASS systems work, so yes it has been tested. And yes, any loss of coordination between clocks would render those systems useless. No, it's not reasonable to get GPS-style data after the fact, or with only two time bases.

      Comment


      • ADS-B is NOT a transponder function. It is separate avionics. It has it's own GPS receivers and formulates it's own data packet extensions. It is broadcast as an extension to the Mode S transponder making it a Mode ES transponder. Mode S does not broadcast a position within it's data packet. Baro altitude is part of the data packet as well as ICAO codes, Flight numbers and much more. ADS-B does NOT use GPS altitude, it uses BARO altitude or Mode C information.

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        • Originally posted by cretanrunner View Post
          Can anyone explain what info is derived from the satellite pings?
          The main thing that ping() tells you is if the thing that you're pinging is up and running on the network, AND that the network is carrying data.

          How accurate is location info?
          That depends on the source.

          Can altitude be deduced?
          No, deductive reasoning is no substitute for actual measurement.

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          • The 'Elephant in the Room' to me is why we have not heard anything from Boeing or Royles Royce.. They have been way too quiet in this situation.

            Way too many uneducated guesses being layer out as fact or possibilities. Press is going way overboard. They seem to be generating news rather than reporting news. JMHO

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            • Originally posted by Speed Daemon View Post
              That would require extremely accurate and coordinated clocks on both ends. AFAIK neither the Inmarsat satellites nor the plane's satcom radio have such a costly facility.
              No if the inmarsat system time stamps its data and there is a handshake before data starts(a known set of comands to establish the link) and you know how long that command takes to process or there is a deliberate wait time before a reply is given (i.e. plane receives command processes but wait 200ms from receiving the command to sending its reply) you can deduce distance from the satilite by the two way travel time.
              T-EGLF8

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              • Interesting read. Well within fuel range.

                http://www.wnd.com/2014/03/top-gener...r-missing-jet/

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                • Originally posted by TNHunter View Post
                  Interesting read. Well within fuel range.

                  http://www.wnd.com/2014/03/top-gener...r-missing-jet/
                  Nice link! I agree that if the aircraft didn't crash, Pakistan is the most logical place for it to be. After all the mastermind (Khalid Sheikh Mohammed ) of 911 was Pakistani, the Bombay terrorist attack and of course the shielding of Osama Bin Laden were some of the things that Pakistan should be held responsible for.

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                  • Originally posted by Alex Smart
                    Is it known if after it turned to the west did it (if known ?) maintain the 30/35000ft hight ?
                    It's possible that a radar technician somewhere in Malaysia knows the answer to that. We don't know because the Malaysian government has changed its story several times. We don't know which version (if any) of their story is the true story.

                    You have to understand that air traffic control systems used by airliners gets its altitude data from each plane's transponder signal. No transponder, no altitude data. Malaysia claims that the transponder on MH370 was turned off around the time it went missing.

                    If so and it flew until it ran out of fuel, about where would that have been (If it did not change the direction of flight ?)
                    That depends on how the flight management system and/or autopilot was programmed. The FMS can be programmed to go into a holding pattern when the plane reaches its destination, as was the case of Helios Flight 522, which crashed in Athens after a pressurization problem incapacitated the crew and passengers. OTOH other flights with napping pilots have overshot their destinations, namely Northwest Flight 188.

                    If the plane's cockpit was left unattended after the alleged initial left turn, and there were no other turns/waypoints programmed into the FMS, it would have continued on to somewhere west of Australia and run out of fuel. The thing is...if one unusual turn was programmed into the FMS, there's no reason why more turns weren't also programmed. Furthermore there's no evidence to suggest that the missing plane was first directed away from its destination under positive control and after that simply neglected.

                    If we apply Ockham's Razor, we must reject the more fanciful ides in favor of the most straightforward. And with what we know to date, the plane was probably piloted (more or less) up until it returned to earth or positive control was lost.

                    If all of this is known then is the search been carried out in that area ?
                    The area where the plane could possibly have gone is HUGE! It will take a lot of time and money to do an exhaustive search. In addition, some nations have denied SAR overflight of their airspace.

                    Comment


                    • Originally posted by TNHunter View Post
                      The 'Elephant in the Room' to me is why we have not heard anything from Boeing or Royles Royce.. They have been way too quiet in this situation.
                      Both companies are likely targets for lawsuits, so their silence is for self-defense. And since it's not likely to be an engine or airframe problem, they don't really have anything constructive to add at this time.

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                      • My experience is with GSM network but the principle should be about the same.

                        What we got here is a satellite sitting 35000km in the sky and the a Satellite terminal that sent it pings. The pings would contain amplitude (power) information and that is about it (ok and other subscribers identity related information, which identified the aircraft/terminal but contained nothing about location).

                        The satellite coverage is defined by the (2?) longitude lines, so we know the terminal was within those ranges. The way Satellite communication works is that a terminal locks onto and talks to a satellite(s) and a satellite(s) just beam things down to a wide area to be picked up by the relevant terminals at the relevant channels.

                        Based on the amplitude (power), once can extrapolate/deduce the distance of the ping and multiple pings then allowed a rough course to be plotted - but the strength of the ping is symmetrical on both side of the half circle and that is why we got 2 flight corridors. If the terminal had been in contact with multiple sats, then we would be able to triangulate its position. However, it looked like this terminal only talked to 1 sat.

                        So, in conclusion, it provided a very rough estimate of area - several million square kilometers - the areas they are searching right now.

                        I sincerely hope that the mystery is solved soon.




                        Originally posted by Speed Daemon View Post
                        The main thing that ping() tells you is if the thing that you're pinging is up and running on the network, AND that the network is carrying data.


                        That depends on the source.


                        No, deductive reasoning is no substitute for actual measurement.
                        Last edited by flyingduck; 2014-03-19, 22:19.

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                        • If there was an electrical fire and the crew set the auto pilot to return to Malaysia
                          and were then incapacitated, you need to remember that we are now talking about a damaged plane.
                          The Auto pilot requires information from a number of sensors and then returns flight inputs.
                          No-one can predict how a damaged plane will react. Apophenia. ( http://en.wikipedia.org/wiki/Apophenia )
                          What you think was intelligent control. Was. It's called a confused computer.

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                          • MH370 Inconsistent FlightRadar24 data

                            https://www.youtube.com/watch?v=XnfXwyh-8KY

                            Upon analyzing this video and logging the altitude, speed and Vertcal Velocity at a minute interval. It seems the distance traveled does not match the distance calculated using displayed aircraft speed.

                            Flight leaves at 16:41 and reaches cruising speed of 480 knots at 17:03. Crosses K.Terennganu into S.C.Sea at 17:11.

                            The distance from KL-KT is about 210 miles. The distance calculated using FlightRadar speed is about 165 miles.
                            Any body know why there is such a difference ( 210 vs 165).

                            Distance = .5*(time to get to cruising speed) *cruising speed + cruising speed * time at cruising speed. 1.15 miles = 1 nmi.

                            If the times are right, then the speed has to be almost 600 knots for it to cover 200 miles in about 30 mins. Is there something amiss here or is there a tail wind of 120 knots at this altiitude??

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                            • I will add to what I said before:
                              Lets be real folks, there was no fire, no smoke, no flames, no mechanical failure, no catastrophic failure...this was an abduction...motives for this kind of abduction are very high...every other theory doesn't add up...this adds up. Whoever was flying this plane knew what he was doing, and his motives were for evil not for good.

                              Comment


                              • Originally posted by SpaxmoidJAm View Post
                                No if the inmarsat system time stamps its data and there is a handshake before data starts(a known set of comands to establish the link) and you know how long that command takes to process or there is a deliberate wait time before a reply is given (i.e. plane receives command processes but wait 200ms from receiving the command to sending its reply) you can deduce distance from the satilite by the two way travel time.
                                No, ping was never designed to do that. A far more precise clock would be required to gain any meaningful data. Even then, variables such as CPU load could cause large variations in return time.

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