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Malaysian Airlines MH370 contact lost

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Malaysian Airlines MH370 contact lost

Old 5th Apr 2014, 14:07
  #9181 (permalink)  
 
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It might just be coincidental but HMS Astute left Gibraltar early last week en-route the Suez canal. It is the first boat of the class replacing the T class sub force. It has the 2076 sonar plus more.
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Old 5th Apr 2014, 14:10
  #9182 (permalink)  
 
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Twitter

JTwitter ID James Chau ‏@jameschau
#exclusive My source: 37.5 kHz bang on, BUT indicates signal detected 4 only 15 mins. If #MH370 why nt longer? #breaking

‏@jameschau his colleague is aboard the ship who reported the pings.
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Old 5th Apr 2014, 14:33
  #9183 (permalink)  
 
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Ahhhhmmmmmm

If you were on a boat searching for pings on 37.5 and you started receiving them, maybe you would think about...

STOPPING THE BOAT

Is there something with to do with thermal layers that could stop signals from reaching the surface or whatever depth they were towing their sonar array at?

Why would they only receive the ping signal for 15 mins, a month after the plane went down?

Something is not right here. It doesn't make sense to me.
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Old 5th Apr 2014, 14:34
  #9184 (permalink)  
 
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Lompasso

Is there anything else that might have generated the signal?
37.5 is a frequency that was deliberately chosen because there is very little naturally occurring sources in the ocean anywhere near that frequency.

As for other ships accidentally generating that frequency - it is extremely unlikely.

xman80

What do you think happens when you stop towing a weight behind a ship? No wonder it doesn't make sense to you.
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Old 5th Apr 2014, 14:34
  #9185 (permalink)  
 
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Underwater Mountains

And why did the signal last 90s?
Looking at seabed topography picture from PortVale (post #9268) transmission signal could be shielded by underwater peaks with a 90s gap.
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Old 5th Apr 2014, 14:49
  #9186 (permalink)  
 
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ULB Battery Due Date

Just on CNN:

The MAS CEO declared during a press conference that the FDR / CVR - ULB maintenance records indicate that the ULB battery due date is June 2014.

That would imply that these batteries should have been replaced during scheduled maintenance in an A-check at around this time or in the next month or so if the aircraft was still in service to avoid the battery expiring between scheduled maintenance intervals.
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Old 5th Apr 2014, 14:56
  #9187 (permalink)  
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Reported onboard says they first detected the signals as late as friday.
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Old 5th Apr 2014, 15:12
  #9188 (permalink)  
 
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Reporter onboard says they first detected the signals as late as friday
Yet the Malaysians gave their official press conference just a few hours ago and not a whiff of it.

And this Chinese ship is apparently way outside the international joint "co-ordinated" search area.

There's a serious solo run going on here.
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Old 5th Apr 2014, 15:13
  #9189 (permalink)  
 
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rog747;
Time to get the Royal Navy up there quick with our sub HMS Tireless to confirm the pulse signal?
Surely time to send in a P3 to drop some sonobuoys?

Also;
If the MAS flight MH370 Boeing 777 had crashed in that region then any floating small wreckage will be soon reaching the shores of Western Australia due the prevailing weather and sea conditions
Perhaps time to calculate the drift current and dispatch an aircraft to hi-res image potential shore line for debris?
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Old 5th Apr 2014, 15:19
  #9190 (permalink)  
 
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According to CNN "expert", if the Chinese ship is towing the array at the surface and the wreckage is at the bottom there is no way it could hear the pinger. 4400 m depth.....plus no contact with Malaysia or AUS since the original report???? Something is not adding up....
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Old 5th Apr 2014, 15:22
  #9191 (permalink)  
 
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Originally Posted by Red Plum
As for other ships accidentally generating that frequency - it is extremely unlikely.
Could it be that another ship emitted the signal in order to calibrate their detectors? How else can you check that the equipment is working properly?
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Old 5th Apr 2014, 15:22
  #9192 (permalink)  
 
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the common sense thing to do is run back along the track with the microphone much lower in the water.
They might be picking up an interference pattern caused by underwater mountains. Towing the sonar rig in a grid pattern at a consistent depth and creating a map of the signal strength might give them a better picture of where the side lobes and main lobe of the signal lies.
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Old 5th Apr 2014, 15:22
  #9193 (permalink)  
 
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Astounding this goes from the Chinese->media instead of to the search team.

If I did something like that during a search my ticket would be punched pretty quickly.
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Old 5th Apr 2014, 15:32
  #9194 (permalink)  
 
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methodology of towed search

It has been asked why not stop? The answer is that, aside from the practical considerations of a tow, a stationary detector provides no useful information. The 90 sec interval gives an idea of the wreckage being on a line perpendicular to the tow route corresponding to the middle of the 90 sec interval.

The technique would be to circle wide through 270 degrees and survey along the line just mentioned to hopefully detect over an interval thus producing another line. Approach this crossing point from a third direction between the other two to create a third line. The result of the three lines is known as a cocked hat and gives an idea of the position of the source. If the signal strength is measurably variable then the maximum strength gives a position for the perpendicular line.

The signals can be distorted by sea bed features and thermal/ salinity features in the water column.
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Old 5th Apr 2014, 15:41
  #9195 (permalink)  
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Just watching that CCTV You tube link.

She said that the ship detected the same signal on Friday for 15 minutes but were unsure because there were other ships in the vicinity. Then they heard it at 4:00pm Beijing time today for just 90s. Now if they didn't record today. Did they record it yesterday? Something is a miss here. I'm afraid there seems to be no reports of this on Friday. I smell a sensationalist media release like their sat photos last month turned out to be. Was that XINHUA as well?
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Old 5th Apr 2014, 15:48
  #9196 (permalink)  
 
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Is it known what depth this Chinese black box detector was being towed at?

Seems quite fundamental
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Old 5th Apr 2014, 15:57
  #9197 (permalink)  
 
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Originally Posted by XB70_Valkyrie
Astounding this goes from the Chinese-> media instead of to the search team.
Watch the report in Post #9286 again.

The reporter states that China and Australia authorities had been notified.
No surprise Malaysia is quiet, Australia is supervising this.

Originally Posted by PortVale
Chinese press on board the vessel
Why the surprise ?

Western media reps have been present on numerous flights.
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Old 5th Apr 2014, 16:08
  #9198 (permalink)  
 
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If this vessel is ploughing its own furrow miles away from the main search sites, I'd say it was highly unlikely they would be detecting a 'test tone' from another ship.

I would also like to think that anyone generating 37.5KHz anywhere near other search vessels, would let everyone know when and for how long they were doing it.
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Old 5th Apr 2014, 16:25
  #9199 (permalink)  
 
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xman80

What do you think happens when you stop towing a weight behind a ship? No wonder it doesn't make sense to you.
I guess towed arrays come in many different forms, but the ones I've seen were in tubes filled with a paraffin-type substance to give them neutral buoyancy.
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Old 5th Apr 2014, 16:26
  #9200 (permalink)  
 
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sorry Pontius Navigator

devices are made in differing types and can descend below the surface or some types stay on the surface
both can set to listen at different depths etc etc

so a 4000m cable you suggest ? - of course a surface sonar would not hear it

also re wreckage the OP was responding to my original post where i stated
If the MH370 had crashed in that region then any floating small wreckage will be soon reaching the shores of Western Australia due the prevailing weather and sea conditions

seems you may not been reading the whole thread either

Last edited by rog747; 5th Apr 2014 at 16:47.
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