I would submit it is logical - albeit logic serving an outcome we find deeply disturbing and incomprehensible.

If it wasn't for the satellite pings (a detail perhaps not known about or somehow overlooked), we likely would have no idea what happened. But strip away the satellite stuff, and everything else fits with a desire to disappear without trace.

Why? Who knows. But history is full of people who chose to disappear.

Who has been harmed by this? That provides best guess at motive. Well the Malaysian government has been horribly exposed on the world stage. It has generated ill feeling between Malaysia and China (not what he Malaysian government would want).

I am not suggesting it was a particular pilot who supported the opposition. We can't conclude that. But someone (could have been other than pilot) who wanted to damage Malaysia for some reason.

Thanks Finn47,

Lets hope they get some solutions and act on it. The fact they are looking at the Lithium Ion battery rules again is good as well. They were only re-written last year due the UPS- Dubai and the Asiana Cargo - Jeju Island accidents and have confused many.

rampstriker,

It's a 10 ms pulse of 37.5 kHz ultrasound, repeated every 0.9 seconds. That's a duty cycle of 10/900 or about 1.1%.

Thermoclines and Oceanic Ensonification
 

Any student of ASW (anti-submarine warfare) would be familiar with the fact that deep ocean areas contain barriers to the direct propagation of sound. Whether or not a sound penetrates a layer depends upon the relative densities, the steepness of the temperature gradient within and between the layers and mixing characteristics at the layer's periphery. There's little mixing at great depths.

It's not unusual for sound to bounce between layers with little loss in dBA and finally reach the surface layer in an annulus (think the area enclosed by two concentric circular rings), once the thermocline's extremities are reached (i.e. due mixing or shelf shallowing in water depth). That "surfacing" can be hundreds of miles away (i.e. 100's of miles away from the source). Nuclear subs use this characteristic of sound to hide beneath or between layers of different temperature, salinity or density. A good airborne sonar operator could distinguish between first and third CZ's (Convergence Zones) due to the fuzziness / distinctiveness of the sonics. However for a "bottomed" source, the topography will make a difference also (think "shouting in a canyon and the resultant directionally deflected echo effects).

Any ship crossing a CZ annulus could do it (unknowingly) at a quite shallow angle and remain in detection for 150 minutes or cross it at an acute angle (eg outer circumference direct to annulus centre) - and ths maintain contact for only 13 minutes.

It's just another (but very debilitating) weakness of the pinger system - in comparison with a satellite relay of streamed system and GPS data before aircraft impact.

37.5 khz acoustic is particularly vulnerable to a channeled sonic bounce between layers. It's one reason why the USN settled upon VLF and ULF broadcasts for reliable contact with its boomers on station. RF or acoustic, within the ocean's layers, it makes little difference.

Chasing a pinger's weak emanations in deep water is like chasing your tail.

PC live on news 24...

Signals have been acquired two more times and they believe there searching in the correct area

Let me clarify my point.

The "original" southern track scenario, with the crash in the roaring 40's, was weird but at least could make some sense in the way you describe: as a disappearance without a trace in the middle of nowhere.

But this new track does not even "work" as a disappearance. It leads in a definite direction: towards Perth airport. If MH370 continued on this track and had enough fuel, in another 1.5 hours it would end up in Perth.

Here's the route via M641, extended to logical conclusion:

SkyVector: Flight Planning / Aeronautical Charts

[Not a pilot] Thanks, Double07. I am trying to deduce from your note whether people are able to take, e. g., the sixth ping and make an arc for it, and then the fifth ping, etc., to try and determine the path from last voice contact based on average speed. I am not able to determine if that is what you have done or not.

mm43 nailed it.
 

Houston confirmed that Ocean Shield found 2 instances of acoustic event again, as mm43 forecasted hours ago.

link to mm43's post9623 earlier
http://www.pprune.org/8425618-post9623.html

"Two more pings have been detected by the Australian ship Ocean Shield in the search for flight MH370. Air Chief Marshal (ret) Angus Houston, the head of the search's Joint Agency Co-ordination centre, announced the development during a press conference in Perth on Wednesday afternoon.
It revives hope the missing Malaysia Airlines plane's black box is still transmitting data days after its batteries were due to run dead.
http://images.smh.com.au/2014/04/07/...8015-300x0.jpg Crew on the Ocean Shield deploy the towed pinger locator. Photo: AP

Mr Houston said expert data analysis on previously detected signals had found they were not of natural origin, further boosting hopes of a breakthrough.

Excellent news :ok:

Does the pinger detector sled have an IRU and vector sensors or is it just a dumb hydrophone ?

Regardless they presumably now have a cross fix on the position and can launch the AUV...

I THINK he said that they won't deploy the UAV until they can pin point the ping because it takes 6 times as long underwater as it does on the surface.

For those who read my yesterday (deleted) post about a YouTube film with an alleged recent in-flight visit to the avionics bay of a 777.
I am a little ashamed to have added this comment: 'secutity improvement?' (or something like that) which implied the movie was recent. The truth is that the "date added" of the movie (2014/03/18) NOT implies the movie was recorded since MH370 disparition. And a better look at it (what I should have done before posting) shows it is not:
- the cabin layout seems not very recent ... and it is not: at 7:16, you can read on the exit door 'SAIDA EXIT' (so the company is probably Portuguese) and at 7:23 the name VAR?? is then probably VARIG right font on the sheet of the crew rest bed). The four first letters of the same name were also visible under the oxygen tank at 6:12. This company is out from 2006.
- in the E-E bay, avionics are labelled AlliedSignal (in one word, at 4:51). This name was in use from 1993 to 1999 (see AlliedSignal - Wikipedia, the free encyclopedia).
I have not be able to find a picture with the same attendant uniform/apron as seen at 00:30.
The crew rest zone don't look like what I can see on 777 net pictures. Is it one?

There is no other video posted on YouTube by the pseudo Jack Jones. So, no credit. And unknown afterthought from the poster.
So ... post deletion was normal!

I do think the movie has been registered on a France to Brazil (or return) flight: at 1:08 the guide (first officer?) said 'Bon, maintenant' [French] and continues in English (not is native, for sure). And the one who has the camera answer 'D'accord' [French] between 1:49 and 1:50. But it is not from me!

Angus Houston says;
Pings are heard twice more on Tuesday. Analysis of the previous pings have confirmed that they are from man made device and consistent with the expected FDR/CVR pingger. This included the 1.1sec delay in the pings. They are still going ahead with trying out TPL to get more data. The time to launch the unmanned sub with side scan sonar is undecided.

So overall it seems another small but important step closer to locating MH370. Lets hope there is some conclusion soon to the families.

BBC Also updated story to include latest graphic of all 4 ping detection locations.

BBC News - Missing Malaysia plane: Search 'regains recorder signal'

JACC map of 4 ping detections Apr 9
 

Triangulation or other pin-pointing, possibly made easier if its just the FDR emanating signals not both, still has the complications of refraction and reflection from the thermal layers; perhaps other meterological issues.

This therefore could take some time - certainly days not hours; with the other vessels kept away (looking for drifted debris) to keep the sound environs as clean as possible while more acoustic events are sought.

Check out this graphic from Washington Post. Just shows what they are up against!


The depth of the problem - The Washington Post

:ok:

According to the Australian Joint Acoustic Analysis Centre the pings detected are not "of natural origin".

One more step closer.

FYI Malaysia and Indonesia now deny any evidence exists pointing to the so-called skirt-around-Indonesia track.

MH370 search: Plane had not skirted to Indonesian airspace as reported by CNN, says Hisham - Nation | The Star Online

I am of the view that MH370 never went west at all but instead had an in-flight emergency and turned south towards the nearest airfield, one they'd recently flown over. Turn, drop alt. Decompression/hypoxia, all aboard dead, miss approach. Zombie flight magically goes all the way to where they are searching now.

Agree, great graphic but there is a question unanswered. If the depth of the hydrophone is 4,600ft and they are correct that it would have to be at 6,000ft to have detected the ULB, then either the hydrophone depth is wrong, or their opinion of the pinger range is wrong (9,000 feet - 2289m) or the pinger is not as deep as 15,000ft.

As they did not seem to pass on top the pinger, maybe it is not even at 15,000ft.