Missing Malaysian Airlines MH-370 - Thread 6

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Yes, but there are a range of Northern and Southern lines and speeds, leading to a range of burst frequency offsets at each timestamp, not shown or alluded to.

Cross post garlic - see you around on the space elevator

I have just seen that an Malaysian official has told the relatives of the passengers that "miracles do happen." I really feel this is unkind. Building up hope where it appears there is none .

Well I suppose strictly speaking they do i.e. that Mexican guy who was afloat for over a year?

I don't believe this to be the case here though unfortunately.

the cruelest thing seems to be saying we have evidence but it's sealed. that is such a blow to the relatives i should imagine.

anyway the whole world seems crazy at the minute between this, the troops descending on the ukraine, israel shutting all of it's embassies. should imagine there are a lot of fundamentalist end timer types utterly convinced this is it. hope it doesn't make me 'swivel eyed' to point that there is a lot going on in the world right now that is worrying

"Chinese patrol ship Haixun 01 and Australia's HMAS Success "reported they have retrieved a number of objects from the ocean but so far no objects confirmed to be related to MH370 have been recovered", the Australian Maritime Safety Authority (Amsa) said late on Saturday."

1. Surely there are other Northern tracks that more closely match the data ?

I think the assumption was a straight line, constant speed track (shown as 450 knots) at the angle that put the plane onto the last known arc.

1. And correspondingly there are other Southern tracks which match the data less well than the chosen Southern track ?

As above.

1. Why is there no data between 18:29 and 19:40 nad similarly between 22:40 and 00:11 ?

The handshake has been described as happening every hour, but maybe it's not a constant gap.

Mail based rumours that that pilot's marriage had ended, and he had retreated into a shell.

I've just had a look at his Facebook page - didn't before now, as it feels ghoulish. He was devastated by the election outcome last May. Seems to have posted very little since then. Obviously, I don't know whether recent posts have been removed but there are a few randomly typical posts of stuff he likes until January, when it stops.

One of the popular theories in Malaysia was that he attempted to hold the plane hostage for Anwar's release.

He seems to have been such a sweetie! Terribly sad, whatever the truth.

Good to see a retired British Air Marshal is using the opportunity to moan about our defence cuts

Defence experts in the region claim that China’s vast flotilla of search vessels has a dual purpose – to send a warning signal to Japan and the Philippines, its maritime rivals in the Far East, with whom it is embroiled in a number of territorial disputes. - Daily Mail

It's a flippin' porridge, isn't it :(

Garlic, a lot of people were gutted after the election. Some might say more than half of the electorate It's a big assumption to jump to that that had anything to do with this.

Just coming back to this - and then going to bed, as I've lost my hour!

The handshake has been described as happening every hour, but maybe it's not a constant gap.

It's automated. Automated systems don't make ad-hoc alterations to their schedules.

Yes, I know, Loopy. He was devastated though. I will be rocked by fear & disappointment if my country votes this bunch of incompetent loons (imo) back in next year, and I can imagine how much more urgent it could feel to someone who's campaigned so passionately in a country where the politics are even more openly corrupt.

I'm not drawing conclusions, just commenting.

As an aside - jailed for sodomy! I know it's only 50 years since we did that, but how archaic does it look now?!

It is odd about the automated 'ping' not appearing to be automated. So much just doesn't add up.

"It's automated. Automated systems don't make ad-hoc alterations to their schedules"

Does the Ping originate from the satellite or the plane, I can't remember?

Oh, that's a good question! None of the explanations or diagrams I've seen clarify this (bloody journos being even less technically literate than me!) Most of them even leave the ground station out of it. Hang on, I may have to waste half an hour of a sunny Sunday ...

The pings are sent from a ground station to a satellite, then onto the plane, which automatically sends a ping back to the satellite and down to the ground station.
www.afp.com/en/news/satellite-pings-revealed-missing-malaysia-planes-path

Britain’s Air Accidents Investigation Branch (AAIB) says evidence of the final, partial signal between the MH370’s L-band terminal and Inmarsat’s gateway Earth station occurred March 8, when the plane vanished en route from Kuala Lumpur to Beijing.
www.aviationweek.com/Article.aspx?id=/article-xml/awx_03_25_2014_p0-675203.xml

If the ground station does not hear from an aircraft for an hour it will transmit a ‘log on/log off’ message – a ‘ping’ – and the aircraft automatically returns a short message indicating that it is still logged on, a process described as a ‘handshake’.
No response was received from the aircraft at 01:15 UTC, when the ground earth station sent the next log on/log off message, indicating that the aircraft was no longer logged on to the network, it added.
Therefore, at some time between 00:11 UTC and 01:15 UTC the aircraft was no longer able to communicate with the ground station – consistent with the maximum time the aircraft was able to fly.
www.inmarsat.com/news/malaysian-government-publishes-mh370-details-uk-aaib/

The ground station generates the auto-ping. It tells the satellite to contact the plane. Plane pings the satellite back directly, according to what I've been able to find.

This doesn't explain how the 'partial ping' is described as an incomplete contact between the ground station and the plane: none of these descriptions involve direct contact between the two It would be more logical, I'd have thought, for the plane to ping back the ground station, not the satellite itself ... but what do I know?!

Oh, OK, Inmarsat again: When an aircraft is out of range of VHF/UHF radio, such as in oceanic airspace, Inmarsat enables air traffic controllers to stay in touch with the aircraft.
www.inmarsat.com/news/faq-inmarsat-aircraft-safety-communications-services/

It pings back to the satellite, because there's no guarantee it will be able to reach the ground station. Still doesn't explain this partial ping, though, or why the chart showed irregular pings.

And the satellite is basically just a mirror. All the work is done by the ground station.

I found this interesting - it's a diagram of Inmarsat's coverage. The one we're being told about is 64E, the purple one. I wonder whether they've checked the two overlapping ones for contacts with MH370? (They must have done, mustn't they?)
www.extremetech.com/extreme/179112-how-satellites-tracked-down-flight-mh370-and-why-we-still-cant-find-the-plane
Right, that's it for now!!

Thanks garlic.

I wonder if the ground station pings every hour but then the satellite "bundles up" instructions for various ground stations and planes and does them at its next window? That could lead to differing times between pings.

I assume the plane pings the satellite not the ground station because it might not have line of sight to the ground station (mountains/curvature of earth in the way)

That's a great article garlic.

So Inmarsat have four satellites, one over the Atlantic, one over South America, one over the pacific and the one in question over the Indian Ocean.

I suspect that the set up may be that each satellite only sends pings to planes nearest to it, or maybe to a set list of routes if a plane moves between one and the other along its route, otherwise each would be sending out and handling many times more pings.

so it pings every hour 'unless' it's already heard from them? so it would ping an hour after last contact rather than at a fixed time each hour. does that suggest there was contact in those times with the longer than an hour gaps? what would count as contact?

Yeah, that makes sense, Doctrine. The antenna on the plane is supposed to initiate the ping - at what intervals, I wonder? Then the ground station has a go if nothing came for an hour. It does explain the irregularity, but not what conditions might prevent an aircraft from sending out its pings ... slow failure of its electrical systems might do it, I guess. Or a bit of debris on that particular spot at that moment?

I think that the aircraft didn't send out the pings routinely & had to be contacted by the satellite because it had no data to transmit after the ACARS system had been disabled?

The early pings on the graph are probably consistent with take-off when there was a lot of info to send via ACARS. The bit that's more difficult to explain is the frequency of the pings round about the time of the possible turn when ACARS was already off. Though maybe that is consistent with the sudden changes in direction/zig - zagging speculated on?

I think this is quite useful