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Malaysian Airlines MH370 contact lost

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Old 7th Apr 2014, 00:08
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JSmithDTV:
I still maintain the the 24m object "awash" with water (you need to be able to see detail to refer to something in this way) was a wing which had sunk by the time they tried to find it...
One of the problems with multinational teams such as this is language used where for some of the people involved, English is not their first language. Hanging on how a journalist, politician or anyone else has phrased something is really making something quite often out of nothing.

You do not need to see detail to refer to something in this way - awash simply means just level or just above the surface level of the water which is pretty obvious that object was. Use of that word does not carry the inference you have associated with it regarding the detail needed.
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Old 7th Apr 2014, 00:49
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Could the Chinese report be a PR stunt (again)? I am by no means an expert and I guess this will be honored by being deleted from the mods - but detecting a plane everyone is looking for since a month with a rubber dingy, what seems a hydrophone on a pole and - seriously - iPod earphones? Apart from noise interferences from the dingy's motor (and it might be not in that frequency, no idea) but I would expect you want to wear a serious pair of over the ear headphones.

Regarding the two locations - possibly Voice and Data recorder at different locations (or sound carried from one to the other location but given the distance rather unlikely) - anyone daring to make an educated guess to the implication of such a find?

Last edited by grimmrad; 7th Apr 2014 at 17:58.
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Old 7th Apr 2014, 01:00
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lynw
Hanging on how a journalist, politician or anyone else has phrased something is really making something quite often out of nothing.

You do not need to see detail to refer to something in this way - awash simply means just level or just above the surface level of the water which is pretty obvious that object was. Use of that word does not carry the inference you have associated with it regarding the detail needed.
The comments were not from a journalist, they were by AMSA.

There is no way from the grainy images we plebs were provided that you can say something is "awash" with water. This is a term used for something that is bouyant, but not completely floating on the surface. It's a very descript term that implies they have higher res. images than what we were shown, likely also in colour...

Last edited by JSmithDTV; 7th Apr 2014 at 01:01. Reason: spelling
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Old 7th Apr 2014, 01:26
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Spread spectrum underwater location beacon system
Includes transponder mode to activate pinger.
The process gain in a spread spectrum system can easily be 10, 100 or more increasing the range by those amounts.
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Old 7th Apr 2014, 01:30
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Finding Things Underwater

I am not an Aviator (Ianaa). However, I have spent many years trying to find long tubular objects underwater. First of all you need to know that every military naval vessel does a BT drop at least every 24 hours. These drops allow plotting of convergence zones for the local area. So, if I were for looking for a known frequency at a known signal strength at a known depth (the bottom) at a datum that I might have, the first thing I would do is deploy a device away from my ship. Why? Surface vessels pretty much suck at trying to find subsurface targets because they are too noisy. So using a PIB is a good idea. Get away from the ship and try some soundings based on convergence zones that may be calculated on a known datum. So, while it may seem crude, I thing the Chinese are being innovative with the equipment they have available. Regarding the posturing, the guys and gals that are doing the search are working to the best of their professional ability. The posturing happens at the High Command/Political level. The folks on the aircraft and the ships are just doing their jobs to the best of their ability.
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Old 7th Apr 2014, 03:00
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Re pingers:

this British laboratory's "sound absorption calculator"
Calculation of absorption of sound in seawater

suggests only ~ 5 db/km signal loss at 37.5 khz
and the signal starts out >100 db
which to me says a sophisticated portable instrument on the surface might very well hear those things.

so the Chinese dinghy idea doesn't defy physics.
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Old 7th Apr 2014, 03:38
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I would say about half the posts to this thread have been deleted since #1.

A lot of the deletions are because the topic has been debated to death 100's of posts / pages ago and people are too lazy to search first.

Some seem to have been driven by geopolitical concerns, defamation concerns etc

Some of the more insane theories (aliens, gods) etc get shot down

I wouldn't worry too much there are still 10,000 posts to read
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Old 7th Apr 2014, 04:11
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Has detected signals like those omitted by Black boxes.

1st signal held for 2 hrs and 20 minutes

2nd detection held for 13 minutes but more important two "distinct" signals were heard.

They haven't found the aircraft yet and he stressed this so to use the info sensibly
until the signals could be verified.

Depth here is 4,500 metres !
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Old 7th Apr 2014, 04:13
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Angus Huston Says;

2 pingers heard simultaneously and they think its from both boxes
Pingers heard for 2 hours + and then after the turn of the vessel it was lost and picked up again and heard for 13 mins.
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Old 7th Apr 2014, 04:26
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Amazing news! Hopefully the plane is not below 4500 meters...so they can get back to the surface the remains of it.

Congrats to the Aussie and Chinese teams, superb job.
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Old 7th Apr 2014, 04:26
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I missed it. I assume that Ocean Shield is in a different location to where the Chinese thought the heard something?
Ocean Shield at north end, Chinese ship at south end of high probability area.

He held up a map showing the locations of both ships and the high probability area (of presumed impact).

I wonder if there is a chance the audio signal could propagate quite a distance if deep underwater conditions enabled that?

He's also saying the search grid turn arounds take 3 hours (as we've heard on here, they're difficult)

Of course CNN crawl is saying "US towed pinger locator hears signal..."
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Old 7th Apr 2014, 04:26
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Interesting re the towing of the device.

It is at 3000 metres and takes 3 hours to turn the ship around with the length of cable
that is out the back

Commodore Levy comes across very well indeed. Liked his explanation of how sound travels through water.
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Old 7th Apr 2014, 04:57
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Although didn't the Chinese say they also had sight of some kind of surface debris (not necessarily plane related) yesterday?
At the press conference that just happened Houston said the white squares seen yesterday were checked and are not related to MH370.
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Old 7th Apr 2014, 04:58
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I didn't get a distance between the two, not sure he said it.
I think he said 300k but also the usual provisos about cold water layers, salt layers and acoustics in the sea not being like in air so weird things can happen.
Ah sorry he talks in nautical miles. So 300 nautical miles.

Last edited by mmurray; 7th Apr 2014 at 05:21.
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Old 7th Apr 2014, 05:11
  #9355 (permalink)  
 
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A map:

https://twitter.com/SteveGrzanich/st.../photo/1/large

Water depth reportedly 4,500 m.

https://twitter.com/cctvnews/status/...586752/photo/1

Australian ship detects signals consistent with black boxes - Xinhua | English.news.cn

An earlier post said one ship's cable was 3,000 m, which could still bring it within range of a ULB, but with a much smaller horizontal footprint.
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Old 7th Apr 2014, 05:27
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Angus Houston's mention of 2 apparent (but 'distinct') ULB signals (presumably CVR + DFDR) is significant.

Amid much of the 'scenario' speculation (!) on this thread, if the aircraft did end up relatively intact on the sea-bed & still containing the boxes, how might they be retrieved?

[1] Can any of the deep-submersible AUV/ROVs perform any kind of hull cutting activity?

[2] Can hoisting gear be remotely attached to any fuselage structure?

Last edited by deanm; 7th Apr 2014 at 05:30. Reason: spulling!
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Old 7th Apr 2014, 05:46
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The Australian chief of the MH 370 flight search team just announced that signals sounding like pingers have been heard by an Australian naval vessel. 1st signal held for 2 hrs and 20 minutes. 2nd detection held for 13 minutes but more important two "distinct" signals were heard. The ocean depth in the area is 4500 M. The ship is doing an expanding square search attempting to pin the location down to a 2 mile square. This will take another day or two since they search with a USN towed receiver at (I think) 3000 M and at 3 KT. It takes 3 hours to make a turn and a total of 7 hours a leg. Compared to the speed of aircraft searching, the time to do a deep water search is very long!

The location of the presumed target is within the search area defined by the latest satellite analysis.

They will not claim a find until parts of the 777 are recovered on the surface, or pictures of the remains are taken at the sea bottom. After the location is pinned down sufficiently with the pinger listening device, a remotely controlled vehicle rated at 4500 M will use a side scan sonar to accurately define the location and then take pictures.

It looks like it will take many months to recover and read out the recorders, but eventually we will all know what happened during that final flight of MH 370.

Last edited by bob1vt; 7th Apr 2014 at 19:04. Reason: Fix uncertaintly of ship nationality and search depth.
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Old 7th Apr 2014, 05:50
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What, (if anything) could go down to +4500m besides the submersible they have.
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Old 7th Apr 2014, 05:51
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Glomar Explorer is in Indian Ocean.....
GSF EXPLORER - Drill ship: current position and details | IMO 7233292, MMSI 576830000, Callsign YJQQ3 | Registered in Vanuatu - AIS Marine Traffic
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Old 7th Apr 2014, 05:51
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British or Australian (I missed which one) naval vessel
ADV Ocean Shield as per picture here

MH370: black box-type signals picked up twice by Australia's Ocean Shield | World news | theguardian.com

and it's wiki page

ADV Ocean Shield - Wikipedia, the free encyclopedia
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