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Topic Title: Finding aircraft that mysteriously vanish
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Created On: 15 March 2014 01:11 PM
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 15 March 2014 01:11 PM
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jencam

Posts: 608
Joined: 06 May 2007

Is it realistically possible for an aircraft like MH370 to completely vanish unless it was deliberately sabotaged before take off? There have been reports about how some radio transmitters on the engine were sending data to satellites several hours after the secondary radar transponders were switched off. Surely these could be used in a similar way to GPS to pinpoint its location. Many aircraft on long distance flights now carry an Inmarsat satellite telephone that works even if other communications fail or can be used to report a hijacking. Was one installed on MH370?
 18 March 2014 06:16 PM
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jarathoon

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Joined: 05 September 2004

Sometimes seismometer networks can be used to pick up airplane crashes or other large explosions on land. However I am not sure this works if a plane crashes into the sea. The only other detection network at sea are submarine listening devices, and I am not use how sensitive they are to the impact sound of a large jet plane hitting the water.

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James Arathoon

Edited: 18 March 2014 at 06:25 PM by jarathoon
 19 March 2014 08:34 AM
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ectophile

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The aircraft data transponders wouldn't be a lot of good to track the aircraft. Each satellite receiver covers a large area, so all you can tell is which satellite's footprint the aircraft was in.

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S P Barker BSc PhD MIET
 19 March 2014 12:24 PM
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jarathoon

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Originally posted by: ectophile

The aircraft data transponders wouldn't be a lot of good to track the aircraft. Each satellite receiver covers a large area, so all you can tell is which satellite's footprint the aircraft was in.


If a second satellite picked the last data ping of the aircraft, and it had a reasonably constrained overlap with the first satellite (northern or southern hemisphere even) then this would help.

In the same way other satellites (presumably military) NOT picking up the last data ping of the aircraft is more information that could be used.



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James Arathoon
 20 March 2014 11:18 PM
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jencam

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There's a very interesting theory by Keith Ledgerwood that MH370 switched off its transponders then changed course to enter the flightpath of aircraft SIA68 that was flying from Singapore to Spain. MH370 caught up with SIA68 then flew very close by, possibly on top of it, across the Bay of Bengal. When both aircraft entered the airspace of India they showed up as one single blip on the primary radar and only the transponder information of SIA68 would be received by air traffic control and the military tricking them into thinking that there was only one aircraft rather than two. Both aircraft proceeded across India and into the airspace of Pakistan whilst all the time showing up as just one on radar and ATC transceivers. Somewhere over Turkmenistan or Kyrgyzstan out of the range of radar the two aircraft split away from each other. SIA68 continued flying to Spain and MH370 was landed in some remote part of Central Asia or China. These final locations are a perfect match up with the 7.5 hours of total flight time on the northern curve generated using the pings of data received by Inmarsat.

http://mh370shadow.com/

Is this realistically possible with the primary radar systems in use in India and Pakistan? Approximately how close to each other do two aircraft have to fly to appear as one blip on a radar?
 21 March 2014 12:55 AM
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jarathoon

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There seems to be enough information to make investigators very confident that MH370 ended up in the southern indian ocean.

[Baring exceptionally abnormal atmospheric conditions beyond all reason to what you would normally expect or very sophisticated actions to spoof and deceive the inmarsat satellite, both presumably unlikely]

Given the working assumption that MH370 ended up in the southern indian ocean somewhere and there are only 18 days left before the black box beacon runs out of batteries, some of the engineering questions are:
1) how do they optimise the search patterns for debris floating on the sea surface.
2) how do they maximise the detection distance at which equipment can detect the blackbox emergency radio beacon. Is it possible to to rig up an under water radio antenna and amplifier that can pick up the signal from the blackbox radio beacon at longer range than normal.
3) is there some material component of the Boeing 777 that when mixed or reacted with sea water produces a widely dispersed chemical or radioactive signature that can be measured at exceptionally low concentrations down current. Equipment to pick up the scent as a dog might.


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James Arathoon
 21 March 2014 11:03 AM
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jencam

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I was inclined to say that MH370 had been crashed into the drink in one of the most remote and deep parts of the Indian ocean until I encountered the intriguing theory about it hiding in the radar shadow of SIA68. Does anybody in the IET possess enough knowledge of radar to be able to conclude whether this theory is realistically possible?

This all reminds me of one of my son's pieces of artwork from primary school consisting of a rainbow with a pot of gold at the right hand end and a sign saying "The pot of gold is at the other end" at the left hand end.
 21 March 2014 11:50 AM
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jarathoon

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Originally posted by: jencam

I was inclined to say that MH370 had been crashed into the drink in one of the most remote and deep parts of the Indian ocean until I encountered the intriguing theory about it hiding in the radar shadow of SIA68. Does anybody in the IET possess enough knowledge of radar to be able to conclude whether this theory is realistically possible?



This all reminds me of one of my son's pieces of artwork from primary school consisting of a rainbow with a pot of gold at the right hand end and a sign saying "The pot of gold is at the other end" at the left hand end.


Presumably you are thinking of the special case where there is no overlapping radar coverage, and/or radio source and receiver are located in exactly the same place. i.e. not a bi-static or multi-static radar installation with one or more receivers located away from one or more transmitters.



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James Arathoon
 21 March 2014 03:12 PM
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jarathoon

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The cargo on MH370 included Lithium Ion batteries: so there are reactive chemicals and organic solvents on board in these batteries which will presumably be leaching out...

https://www.youtube.com/watch?v=ssQnWnBBXuo



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James Arathoon
 22 March 2014 11:43 AM
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jencam

Posts: 608
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Originally posted by: jarathoon
Presumably you are thinking of the special case where there is no overlapping radar coverage, and/or radio source and receiver are located in exactly the same place. i.e. not a bi-static or multi-static radar installation with one or more receivers located away from one or more transmitters.


I ask again if anybody has enough knowledge of the radar systems used in India and Pakistan to be able to determine whether it is realistically possible for a Boeing 777 to hide in the radar shadow of another aircraft. What would be the minimum separation distance between two objects before they are resolved as two objects on a radar screen?

There must be some members of the IET who are experts on radar considering that it's an organisation biased towards defence and professional electronic engineering.
 26 March 2014 08:22 PM
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whyther

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It is perfectly possible for MH370 to have hidden in the radar shadow of SIA68, because that aircraft would have flown a very predictable course and a good pilot could have followed it close enough to have been seen as one aircraft on radar. There are often "ghost images" on radar, especially in regions at the limits of radar coverage and where coverage overlaps, and it would not be surprising if a Controller had dismissed a "double-blip" as a ghost.
However, such a scenario assumes absolutely perfect timing by the person planning such a feat, and a small delay in either aircraft's timing away from its flight plan would have made such a rendezvous immensely difficult. For myself I see the much simpler scenarios of a cabin pressurisation problem or of on-board fire as much more likely.
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