Malaysian Airlines MH370 contact lost

[keithlaaks]

ReadMyACARS - Assuming the Inmarsat doppler values are accurate, I ran the math which gave me the track and speed.

Inmarsat Values
[[2014/3/7 19:40:00, -109],
[2014/3/7 20:39:59, -140],
[2014/3/7 21:40:00, -169],
[2014/3/7 22:40:00, -202],
[2014/3/8 00:11:00, -250]]

Assuming a straight track heading 182, mach 0.39 @ 12000, the predicted doppler values are very close: [-102.21237107180059, -140.52053354680538, -174.36227202415466, -204.76829959079623, -247.19930766150355].

No other combination of speed and track comes close.

But with such a slow speed, the plane could not have headed off towards the west for long. It would have pretty much very quickly had to start heading south at around 0.81. The other Inmarsat doppler values support this. Then slowed down and dropped altitude at around 19:00 GMT.

Full details and kmz file see zs6tw.wordpress.com

[Aireps]

Originally Posted by uksatcomuk

If you strip out all the debris , rocket bodies and decommissioned birds you are still left with a lot of active platforms.
These satellites have both eyes and ears on this region.

Satellite observer Marco Langbroek came to a similar conclusion:

"The southern Indian Ocean arc is slightly less well covered (no TRUMPET or NOSS coverage)
but was nevertheless in view of several geostationary Mentor SIGINT satellites.

Full blog text: Could US Military SIGINT satellites help to narrow down flight MH370's last location?

[TheShadow]

Ocean Shield and Chinese Vessels' widely separated 37.5khz detections

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

They'd need to modulate that NW Cape signal in order for it to be ruled out as a potential source.

[silvertate]

Speed-Altitude of MH 370

ReadyACARS:

A couple of inconsistencies spring to mind.
1. If the aircraft flew faster, and ran out of fuel sooner, why is the search area so close to Australia? The aircraft left Malaysian radar at 0215 local and the last Inmarsat contact was 0811, so if it was moving faster in the same given time, its distance traveled would be longer, but its time aloft would be slightly shorter.

As I pointed out in post 8741 - for the aircraft to end up more to the northeast it needs to fly slower, not faster ... (shorter distance flown, in the same time). The confusion is probably that the aircraft was flying lower, so it had a FASTER IAS but a SLOWER TAS.

ie:
39,000' 260 kts IAS = 463 kts TAS. (slower speed = faster TAS)
10,000' 290 kts IAS = 335 kts TAS. (faster speed = slower TAS)

http://www.pprune.org/rumours-news/5...ml#post8408255



If your calculation for a required 360 kts groundspeed is correct, to end up in that search location, then we have a range of possible speed-altitudes to consider (assuming no wind and TAS = groundspeed).

312 kts at 10,000' gives 360 kt TAS
285 kts at 15,000' gives 360 kt TAS
262 kts at 20,000' gives 360 kt TAS
240 kts at 25,000' gives 360 kt TAS

Since they said the aircraft was going 'faster', one suspects that the 10,000 ft or 15,000' speed/altitudes are the more correct.

However, if someone here has the fuel-burn speed/altitude tables for a B777, they could easily work out from this information exactly what altitude MH370 was flying at (plus or minus the wind). We have the distance, time and fuel-load, and the inly other variable is the speed-altitude. And i imagine only one speed-altitude configuration will comfortably fit the data.


Here is a copy of the image i posted previously (not to any exact speed-scale).
Yellow = high TAS flight
Scarlet = medium TAS flight
Purple = slow TAS flight

[uksatcomuk]

Marco and I have similar interests...the point I am making though is that until recently we may have thought that these birds monitor specific targets....however recent intelligence indicates that everything is scooped up and stored , electronic data...comms.... everything , 24/7

So somewhere in that harvested data there must be more info on the flight than is being released.
Of course the problem is that by releasing that info , the capability of those assets would be revealed.

[onetrack]

This graphic, courtesy of Xinhua News shows 3 Chinese ships in the Northern search area and 4 Chinese ships in the Southern search area, with the Haixun 01 in the centre, where it picked up the 37.5kHz pings. It's entirely possible the Haixun 01 was transiting the Northern zone to the Southern zone and was looking for pings as she went.
It's been stated that the pings were picked up by simply dropping a hydrophone over the side of the RIB. That's the reason for the surprise.
It's sort of like you throwing in a unbaited fishing line on a quick test of the waters, and suddenly landing a big one.
It's simply not possible to tow a pinger locator with an RIB, the weight of the cable alone would sink it.

There's nothing sly, nor any signs of a totally independent operation by the Chinese. All Xinhua news items refer to Angus Houston of the JACC as the "leader" of the search operation.

For obvious reasons involving language and chain of command, the Chinese are not going to have Angus Houston giving orders directly to every Chinese item of equipment - the area of interest will be indicated to the Chinese and they'll be left to operate as a group, using their regular chain of command.

The major problem is the Chinese news journalists on the Chinese ships and aircraft who will obviously send any news home to China first, in the hope of a "scoop".
Journos operate the same, the world over. Angus Houston has subtly reminded them, that any "breaking news" really needs to go to him, first.

[Jess09]

Digital needle in digital haystack

It is also possible that the reverse is true: that because they scoop up everything, finding any one thing is quite difficult. If that is so, they may not want their own paymasters to realize how little they are actually getting for all the money they spend on such surveillance.

[Heathrow Harry]

That well known PLA-Navy Ship "HMS Echo" will arrive first 02:00 Monday morning

The Chinese vessel equipped with full detection equipment will apparently stay were she is still checking that area

the RAN "Ocean Shield" will follow "Echo" when she has finished her current search area

[Porker1]

Surface hydrophone

This BBC video shows the Chinese searchers using a hydrophone on a stick, over the side of a zodiac. Doesn't really tally with the info on this thread that the acoustic signals from the FDR and CVR won't reach from the seabed up to the surface.
BBC News - MH370: Plane search signal 'important lead'

[polarbreeze]

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.

[onetrack]

Doesn't really tally with the info on this thread that the acoustic signals from the FDR and CVR won't reach from the seabed up to the surface.

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" ...

[Nemrytter]

So , who is not coming forward with what they have I wonder ?

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.

Assuming the Inmarsat doppler values are accurate, I ran the math which gave me the track and speed.

Does this correct for the motion of the satellite?

[Porker1]

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.

[Andrewgr2]

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.

[500N]

"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 !

[RJC]

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?

[TEEEJ]

Originally posted by Henra

That could indeed be what lead them to call it a rubber dinghy. It still raises the question: Why would one want to tow such a heavy and slow maneuvering thing as a pinger locator (especially when being deep and on a long line) with something as fast and nimble as a RIB? Do we have an idea of the depth it was travelling?

From video footage.

The DPL-275 steers users to pingers operating between 5 and 80 kHz. It can be used as a diver-held unit or converted to a surface unit using the DHA-151 Surface Directional Hydrophone Kit.

Teledyne Benthos Locators - DPL-275 Locator

Video at following link.

Missing Plane: Three Acoustic Signals Detected

[cwatters]

On the very last day of the 30-day pinger battery window

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.

[mbriscoe]

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.

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.

[500N]

"that a reporter was aboard a patrol boat"

?????????

Why not ?

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