I had taken that hydrophone-on-a-stick-from-a-rubber-dinghy to be somebody's B-roll that had been added for effect and was not necessarily how they picked up the signal. That B-roll was NOT in the original report from the ship, which is here:
Chinese Ship Detects Possible Black Box Signal in Search for Malaysia Airlines Plane

By the way, in that footage of the Zodiac, don't you think the sea looks remarkably calm for the far reaches of the Indian Ocean? It's like glass.

Does anyone know where that footage of the Zodiac first appeared and who released it? It apparently was not part of the first news release.

Re-read Pontius' post about underwater acoustics at post #9328.

"It (the signal) may near the surface at some distance from the source in a narrow range like an annulus. It can then re-emerge at twice the distance and so on" ...

Who says that they have not come forward? Just because data is not made public does not mean that it (or derived information) is not released to investigators.
Does this correct for the motion of the satellite?

And that post is followed by one from Mesoman stating that this might apply to low frequency sound waves (as per whale talk) but not to a 37.5kHz signal that is very rapidly attenuated by distance.

It stretches the bounds of credibility a tad that, in all that water, the Chinese just happened to launch a zodiac in the right place to pick up the signal with a surface hydrophone. Either its an anomaly or they were party to some intelligence unavailable to others.

If the Chinese really did detect the 37.5 KHz signal using a hand held detector and a hydrophone on the end of a pole, it does at least explain why the signals were not recorded. It does, however, seem extraordinary that they would be using such a device from a RIB unless they had very good intelligence that there might be something there.

"Was this ping detector being towed by a large IRB simply a show for the media, the Chinese not being keen on sharing how they've detected the ping signals?"


or the media wanted some footage ????

No civilian is going to know but it looks good !

Didn't the Chinese report say it was heard by 3 people at the same time, so did they really sit those 3 in the Rib with in ear headphones? The video doesn't seem to match previous statements, unless it was just a demo for the TV people?

From video footage.

http://i66.photobucket.com/albums/h261/TOMMYJO/one.jpg

http://i66.photobucket.com/albums/h261/TOMMYJO/two.jpg

http://i66.photobucket.com/albums/h2...MYJO/three.jpg

http://i66.photobucket.com/albums/h261/TOMMYJO/four.jpg

Teledyne Benthos Locators - DPL-275 Locator

Video at following link.

Missing Plane: Three Acoustic Signals Detected

No such thing. It's been explained they are designed to generate pings with a defined signal strength for at least 30 days... but they don't suddenly stop at midnight on day 30. They have said they typically last more like 40 days and at gradually reducing signal strength.

As I recall they justified listening for the pinger by saying that "additional analysis" of sat data had narrowed down the search area to make it worth a shot. The details of that additional analysis haven't been released as far as I can tell.

How many other locations had they tried previously?

The news organisations are suggesting they might have information from the military which has not been disclosed but that probably applies to all parties involved in the search.

Perhaps just a bit of initiative by the Chinese vessel and having a try with the limited equipment they had available, could not do any harm trying.

"that a reporter was aboard a patrol boat"

?????????

Why not ?

They are on quite a few ships and aircraft involved in the search.

Andrewgr2:-
Not only that....there was a video showing two operators on a similar setup sharing a pair of iPod (white cables) earphones, i.e. one side of the earphone pair in each operator's ear!

Philipat:
A dual fmc failure (as one of many possible failures following an MEC fire) would mean a diversion in alternate nav. This has huge potential for incorrect positional entries, particularly under stress of (possibly) cockpit smoke, depressurisation, etc. not to mention unfamiliarity with how to do it. It could explain why the aircraft flew in such a random way, my point being that the erroneous waypoints would have been loaded at the point of diversion or immediately after, not later.
Direct Ortac:
I referred to that AAIB report in my first post. The extent of damage after only 12 minutes was alarming.
According to that AAIB report, there IS smoke detection in the MEC but all it does is place a decrete in the FDR. All that will alert the crew is an EQUIP COOLING OVBD advisory, which is treated almost as a 'nuisance' in the NNC. There is NO EICAS MEC smoke warning on passenger B777s. There is NO fire warning or suppression in the MEC. If that has changed I'm sure someone will enlighten me.
I'm not going to labour the point any further. The scenario I suggest, or something similar, is just one way that all the dots can be joined up between TOC and the SIO. Hopefully we will find what happened soon.

Max depth rating of handheld Benthos is 600 ft for watertight housing . . . . not range of signals received.
Comes with bone conduction earphone.

@ tyler monkey : ah ok, i messed this up , you are right it will be the watertight housing rating.

but nevertheless i,m wondering if its even theoretically possible to get a signal from the waterdepths in this region by a small handheld locator.

when yes, forget the navy towed locator, forget the uk nuclear trafalger class sub - the chinese do it with a zodiac and a teledyne benthos ! :ok:

US also has a strong interest in finding out what happened in case there's some issue with the 777 fleet.

Speed of MH370
 

The slow initial speed you have calculated for the first two hours are due to the aircraft flying tangentially to the ping-rings. The doppler-shift only records the aircraft flying to or from the central location of the satellite coverage (ie: radially to the ping-rings). If the aircraft is flying tangentially to the ping-rings, the doppler-shift will be much smaller.

See my post at No9412 for a graphic. The first two hourly-tracks will give very small doppler-speeds, because the aircraft is almost flying along the ping-ring. (NB, it may not have been flying exactly south like this, i just chose south as an easy example for this graphic. If it had been initially flying 160 degrees, it would have given a slow doppler-speed, just as you have calculated.)

You will also note that ReadMyACARS (post 9401) has calculated an average speed requirement of 360 kts TAS (aka: groundspeed). So even your last doppler speed was slightly tangential to the ping-rings.


Correct me if I am wrong (because circumferential math is not my strong point), but the tangential angles that the aircraft was flying - according to your data and the average 360 kt speed requirement - was:

Hourly track legs:
a. 17 degrees from the tangential.
b. 23 degrees from the tangential.
c. 28 degrees from the tangential.
d. 34 degrees from the tangential.
e. 44 degrees from the tangential.

So it would appear that the initial heading was about 160 degrees, while the final heading was probably around the same, about 160 degrees. The mag-variation will not change this much.

You could plot those values from the claimed start location, using an average track-length of 360nm, and see if the total track tallies with the current search location. But do check that the average 360 kt ground-speed is correct, I am only taking the other poster's word for this (but it sounds about right). Alternative, you could back-plot the route, to see where the start point is.


Updated:
Actually, the ping-rings veer to the southwest the further south you go, so the tangential angle naturally increases as the aircraft flies south. In which case, the aircraft might have been flying a constant heading/track, of about 160 or 165 degrees, with the tangential angles to the ping-rings increasing naturally as the aircraft goes south. Someone will have to plot a more accurate map, to see if those tangentials make a straight track. I suspect that they do.

If anyone has an accurate map, with the location of the ping-rings correctly represented, i can plot it out. Sorry for the error.

It seems they might have been listening in that location due to other data that they had available to them:

from MH370: Chinese, Australian ships verify potential pings from missing jet

artifact harmonic of NW Cape (Exmouth Naval Station) VLF signal. Very powerful signals broadcast acoustically to submarines in the I.O.??


Navy VLF signals RF approx 9 - 35 khz the 'pinger' is 37.5 khz audio (ultra sound)

To those of you plotting the route from the Inmarsat data, the position of the pings is dependent on the Ground Speed not the TAS of the aircraft.