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  Reply # 1023130 10-Apr-2014 21:32 Send private message

Hope you're right ... lemme go watch some CNN :D

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  Reply # 1023132 10-Apr-2014 21:36 Send private message

joker97: Hope you're right ... lemme go watch some CNN :D


Or Sky News. Its just news, little detail, but the means they used to reduce the window will come to light when its located, how they used regression analysis, that will be interesting.

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  Reply # 1023161 10-Apr-2014 22:18 Send private message

New possible signal detected... news.com.au

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  Reply # 1023931 12-Apr-2014 13:43 Send private message

Man in charge of finding MH370 is an RAF reject

An interesting biography of Angus Houston (he was too tall for the RAF)

Malaysia Chronicle




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  Reply # 1024793 14-Apr-2014 11:35 Send private message

All the calculations people are suggesting to find the pingers seem to assume an unimpeded path between the pinger and listener (some people have also mentioned refraction, etc). But the sea floor isn't flat, and (where the topography is pointy) things fall to the bottom of troughs rather than perch conveniently on summits.

So the range of the pingers may be quite limited horizontally, in one or more directions.

FWIW, here's bathymetry of the area: http://www.deepreef.org/biography/robs-blog/155-zenith.html

The comments "the gentle sloping seafloor, (apparently) limited finer-scale topographic relief and the soft sediment nature of the seafloor" suggest that the search for the pinger locations a bit easier than it might have been.

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  Reply # 1024803 14-Apr-2014 11:42 Send private message

oxnsox: These are Acoustic signals not RF, and the salt water salinity, temperature, and subsurface geography means they don't behave quite like RF.

But as you've said there's good maths and smart folks well used to interpreting this stuff ( military and oil industry) so the skills and tools are o
available.


which means they readily refract and reflect at a sniff of a chance.

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  Reply # 1024805 14-Apr-2014 11:45 Send private message

anyway, the pings have gone, and the robot is about to be deployed. watch this space in the next couple of years if we're lucky

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  Reply # 1024810 14-Apr-2014 11:48 Send private message

frankv: All the calculations people are suggesting to find the pingers seem to assume an unimpeded path between the pinger and listener (some people have also mentioned refraction, etc). But the sea floor isn't flat, and (where the topography is pointy) things fall to the bottom of troughs rather than perch conveniently on summits.

So the range of the pingers may be quite limited horizontally, in one or more directions.

FWIW, here's bathymetry of the area: http://www.deepreef.org/biography/robs-blog/155-zenith.html

The comments "the gentle sloping seafloor, (apparently) limited finer-scale topographic relief and the soft sediment nature of the seafloor" suggest that the search for the pinger locations a bit easier than it might have been.


Yep. A ship may be close-ish but on the wrong side of the rise or hillside on the sea floor. Another ship may be futher away but has a line of sight in the other direction but gets a stronger ping. Difficult. They would need to take a conservative sphere where the signal could have emanated from, and look for overlaps. Then there are all the other reasons why the signal bends, or bends less, or is reduced, or reduces less.

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  Reply # 1025390 15-Apr-2014 09:15 Send private message

I had a couple more speculative thoughts about this flight....

I wonder if the path it flew to the Southern Indian Ocean was a Great Circle or a Rhumb Line or something else?

A Great Circle is the shortest path between two points on the surface of a sphere (or oblate spheroid), and to follow it you have to continuously change heading (unless due North/South/East/West). A Rhumb line is a line of constant heading, which will follow a curve across the surface (unless due N/S/E/W). Over short distances, they are near enough the same. Because of this, a Rhumb line is more useful for short-distance navigation.

I guess that a Great Circle flight path indicates that probably the flight director was flying the aircraft, although its possible that it was a person. In either case, the intention was take the aircraft to(wards) somewhere specific, a long way away. OTOH, a Rhumb Line suggests that the aircraft was probably being flown by the auto-pilot, and either it wasn't going anywhere specific, or it was intended for a short distance. So, if we know what type of flight path was followed, we have an indication of what the pilot intended, which is one of the unknowns about this flight.

So, is the path plotted by the pings detailed enough to discriminate between a Great Circle and a Rhumb Line? If so, which was it?

Another factor... does a 777 autopilot maintain a heading relative to the Earth's magnetic field, or based on INS? Or does it maintain a specified ground track, which would be unaffected by winds?

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  Reply # 1025416 15-Apr-2014 10:03 Send private message

frankv: Another factor... does a 777 autopilot maintain a heading relative to the Earth's magnetic field, or based on INS? Or does it maintain a specified ground track, which would be unaffected by winds?


It would depend on what mode the autopilot was selected to, it can do both track and heading.  

franky:  I guess that a Great Circle flight path indicates that probably the flight director was flying the aircraft, although its possible that it was a person. In either case, the intention was take the aircraft to(wards) somewhere specific, a long way away. OTOH, a Rhumb Line suggests that the aircraft was probably being flown by the auto-pilot, and either it wasn't going anywhere specific, or it was intended for a short distance. So, if we know what type of flight path was followed, we have an indication of what the pilot intended, which is one of the unknowns about this flight.


Based on the above answer about what the auto pilot follows (track or heading) you cannot draw any conclusions based on whether the aircraft followed a great circle or Rhumb line.

Also don't confuse a Flight Director with an Autopilot.  They are two different things, you can have an auto pilot without a flight director or vice versa, or they can both be fitted.




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  Reply # 1025448 15-Apr-2014 10:52 Send private message

franky

Thinking about your post some more. If you were to compare the track made good and look at the prevailing winds at the altitude the aircraft flew, you should be able to figure out whether or not the aircraft was in heading mode, but that's about all it would tell you.

Having said that I doubt the one hour satellite pings and the fact that any calculations done with these will have a reasonable margin of error I'd say that being able to plot any Track Made Good with any accuracy would be pretty well impossible.  Also I seriously doubt any of the claims for the altitudes the aircraft might have flown after contact was lost.  They wouldn't know for sure what altitude to use so it would be useless trying to apply any wind drift. 




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  Reply # 1025690 15-Apr-2014 16:40 Send private message

The Bluefin-21 autonomous underwater vehicle has now been deployed.

Bluefin-21 manufacturer's website: http://www.bluefinrobotics.com/products/bluefin-21/

Bluefin-21 product sheet : http://www.bluefinrobotics.com/assets/Downloads/Bluefin-21-Product-Sheet.pdf

Note that it has a 4GB flash drive!




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  Reply # 1027024 17-Apr-2014 17:28 Send private message

Garbage patch

"We have known a long time that especially the recent search area, the new search area they are looking at now, there's a lot of debris there because it is close to what we call the garbage patch, and that's where all of the garbage accumulates," said Erik Van Sebille, a physical oceanographer at University of New South Wales.

"There are five in each basin and one in the Indian Ocean. Everything that has been thrown in the ocean in the last 50 years and still floating is somewhere in this garbage patch."




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  Reply # 1030201 23-Apr-2014 22:28 Send private message

http://www.stuff.co.nz/world/asia/9969557/MH370-may-have-landed-elsewhere-reports

Some noises are made about restarting the entire investigation to look at the location question again.

The more interesting part is U.S lawyers now allowed to move in and begin a process of suing boeing and whoever else they can get their hands on. 10 years from now we could be watching a movie about the tenacious lawyer who solves the mystery lol.


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  Reply # 1030206 23-Apr-2014 22:37 Send private message

Refer rule number one

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