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Malaysian Airlines MH370 contact lost

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Malaysian Airlines MH370 contact lost

Old 27th Apr 2014, 22:13
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@lulu....
While the application is new, the basics are very old....1842 to be exact
The doppler effect analysis is all they have to go on ATM....as far as we know

Last edited by DocRohan; 27th Apr 2014 at 22:15. Reason: deletion in 5,4,3,2........ :)
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Old 27th Apr 2014, 22:31
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Would I be correct to say that the Inmarsat satellite technology that has lead the search to the Indian Ocean has not previously been used to locate a lost aircraft?
No, but calculated positions from satellite handshakes have been compared with known positions of similar aircraft, and other flights of the same aircraft. So it seems quite accurate.

Besides which, if the sounds heard underwater were the recorder beacons, the satellite handshake data is largely academic at this point. The actual impact location was never known very accurately because there's only circumstantial evidence that the final handshake occurred as the aircraft was crashing... it could have continued flying for up to an hour afterwards.
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Old 27th Apr 2014, 22:36
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Pingology

Thanks and i get that it should work in principle, and that theres nothing else better. Its just I reckon that as a plane finding technology it would have been too good to be true. I mean the margins for error are just unknowable.
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Old 27th Apr 2014, 22:44
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Given that the Nuclear test ban treaty people said that their hydrophones at Cape Leeuwin did not detect MH370 impacting the ocean, it may place more weight on a controlled ditching.
This can detect icebergs falling in Antarctica, so if the plane struck the ocean with high force, it should have being able to detect the acoustic waves.
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Old 27th Apr 2014, 22:55
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It is not a new technology, and the next time you go through a police radar trap try and convince them the margin for error is unknowable.
In the end the Satellite track path took searchers to a place where ELT beacons could be heard. That is all that could really be asked of that approach
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Old 27th Apr 2014, 23:09
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SATCOM Equipment

Rampstriker,


The SATCOM system on this era B777-200ER consists of the following components:
  • Satellite data unit
  • High speed data unit
  • Top mounted high gain antenna
  • Beam steering unit
  • Low noise amplifier/diplexer
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Old 27th Apr 2014, 23:12
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I mean the margins for error are just unknowable.
And how do you know that? Clearly the first thing any engineer/physicists knows is importance of estimating the error, without that your calculations are almost useless.
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Old 27th Apr 2014, 23:26
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I understand that the exact number is unknowable, but how low must the probability be that the plane is NOT in the general area where Inmarsat data lead the investigation to that was then shown to house a frequency that is said to be almost impossible to come from anything but the underwater beacon? With these 2 facts, the chances that the plane is not in this area must be approaching zero...correct?
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Old 27th Apr 2014, 23:44
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In the end the Satellite track path took searchers to a place where ELT beacons could be heard.
No, a possible track took them to a place where pings from a presumed underwater locator beacon (ULB) could be heard.
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Old 28th Apr 2014, 00:04
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Satcom equipment

Mr Peabody,
Can you tell us what causes the beam to be steered. Also, each time the beam is repositioned is there communication between the aircraft and the satellite?
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Old 28th Apr 2014, 04:18
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Confirmation today by Aust PM that surface search will finish today.

Underwater search to continue over a "much larger area."

Makes sense. Little prospect of finding debris floating now (although something might wash up on a beach at some future date), and drift analysis now wound be extremely speculative.
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Old 28th Apr 2014, 04:31
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Dumb question?

This may be a dumb question but has the US offered to or provided assistance in the sea surface search by the use of drones? If the haven't the question I would ask is why not? It would appear that they can readily pick out a terrorist target from altitude and conduct surveillance so why not utilise their range and stand off capability to conduct a detailed search of the Indian Ocean instead of putting PC3 Orions and other aircraft at risk.
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Old 28th Apr 2014, 04:37
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Expanded Underwater Search.

According to PM Abbott and Angus Houston the entire 700km X 80km 'splash zone' will be searched using equipment and personnel from private contractors.
The search is estimated to cost ~$Au60mil, and will take at least eight months to complete.
Meanwhile the ships involved in the surface search will remain in the area for 'continuity' and Ocean Shield will continue using the Bluefin-21.
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Old 28th Apr 2014, 06:15
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Would I be correct to say that the Inmarsat satellite technology that has lead the search to the Indian Ocean has not previously been used to locate a lost aircraft?
Yes, and without it the the SAR people would have had nowhere to start looking.

If one accepts the premise that someone rather than something caused this incident and that person hadn't considered that the Inmarsat method could be used then, using the logic of "when you've eliminated the impossible...", the motive must have been to make something disappear permanently.

Which begs the question; what could be so important as to go to all this trouble to attempt to permanently hide?

What was MH370 carrying?

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Old 28th Apr 2014, 07:06
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Just watched the news conference on the new search area and outside contractors. On the positive side the university boffins should get some really good undersea bottom data.
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Old 28th Apr 2014, 07:15
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It's interesting to see that many whales produce sound bursts in the region of 20kHz - but some species produce sound bursts up as high as 40kHz.
Seeing as the signals picked up by the Australian Navy were reported as being around 33kHz, I wonder if this might have been sound bursts from a whale?
Whale sound bursts are reported as travelling up to several hundred kms. The Cape Leeuwin hydrophones of the CTBTO are constantly being bombarded with whale signals.

Whale signals detected by International Monitoring System (IMS) facility: CTBTO Preparatory Commission

One has to ponder whether the major sounds produced by an aircraft ditching into the open ocean would be airborne or waterborne sound, as each has to be picked up by different methods and different instruments. It's interesting to note the CTBTO hydrophones pick up waves crashing, as permanent background noise.

The CTBTO has already stated the Cocos Island infrasound station did not, and could not, pick up any airborne sound from the region where MH370 is supposed to have been lost, due to extreme distance.

Acoustical Society of America - 166th Lay Language Papers
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Old 28th Apr 2014, 07:15
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Or...maybe its like JORN and we Aussies dont turn things on at weekends
All jokes aside...given the reported sensitivity of these things, i am a little surprised that analysis of their data was neg...
Maybe means nothing.
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Old 28th Apr 2014, 07:45
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micis - Station treaty code IS06 is an infrasound station on Cocos Island.

Station profiles - IS06 - Cocos Islands: CTBTO Preparatory Commission

The CTBTO has already searched their infrasound records for any signal peaks that might have come from MH370 on the morning of the 8th March and found nothing. This is because of the substantial distance from IS06 to the suspected crash site, and the high level of background noise created by wind, that is a feature of infrasound stations located on oceanic islands.

http://www.ctbto.org/fileadmin/user_...ines_MH370.pdf
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Old 28th Apr 2014, 07:50
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One Track

You also have huge 30 - 40 foot waves crashing down at irregular intervals which must make some sort of noise. In addition, you have ships coming down off the top of these waves also making large sounds.

How would they differentiate between them ?

And wouldn't a ship make more noise than bits of aircraft falling into the water ?
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Old 28th Apr 2014, 07:55
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It's interesting to see that many whales produce sound bursts in the region of 20kHz - but some species produce sound bursts up as high as 40kHz.
Read it again
Whales are transmitting in Hz not kHz.
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