Malaysian Airlines MH370 contact lost

[JamesGV]

CodyBlade....

In these unprecedented circumstances when an official statement mentions pax as 226 and "colleagues" as 13, it would not be beyond reason to "query" the situation with regard crew ?

Especially when "openness" appears less than ...... "open" !

[oldoberon]

BABA99

Regarding the INMARSAT contribution, this is on their website:

Quote:
Washington Post tracks Inmarsat role in hunt for MH370
[...]
The report added that the handshakes from the satellite – along with assumptions about the plane’s speed – helped Australia and the US National Transportation Safety Board to narrow down the search area to just 3 per cent of the southern corridor on 18 March.
(emphasis added)

It's not clear that what was announced today was anything beyond this?

Of course it does it totally rules out the Northern arc' so they can say with a high degree of certainty all on board are now dead

[OleOle]

RichardC10

thanks for that work and the grasp it gives on the required error margin of the arcs. I would expect the great circle solution to turn to the right (west) when getting closer to the pole. Am i wrong or is the turn just too slight to see?

When going west over Malacca Strait in the first part of the track the a/c was heading always directly towards the satellite. Maybe from this part of the track inmarsat could put more constraints on speed.

Wind drift would also play a significant role.

----
Edit: Richards answer was, on southerly tracks and in lower latitudes great circles and rhumb (constant heading) lines are very similar. Wind drift for both solutions is similar too, and would not help to distinguish.

[awblain]

Richard,

Under similar assumptions does that rule out the Northern route? I assume that must require a weird combination of speed and track changes to remain consistent with the timings.

Neither the distance change away from the satellite between the hourly pings nor any potential Doppler information would by itself rule out a Northern location, any better than reasonable assumptions about the aircraft being spotted enroute ruled it out a week ago.

It's also not really clear why today's news, if the better Inmarsat analysis is all there's been, merits the appearance of the Malaysian PM or the move of the victims' families to Perth.

[DespairingTraveller]

@LLuCCiFeR

p.s. how can the Malaysians now claim that the aircraft crashed into the Indian Ocean, when the aircraft disappeared off the radar and no wreckage has been officially found?

The Malaysians are not "claiming" anything. They are reporting the inescapable consequence of what they have been told by the UK AAIB and Inmarsat - both of them highly professional and competent organisations with no axe to grind in the matter.

[Pontius Navigator]

Originally Posted by OleOle

I would expect the great circle solution to turn to the right (west) when getting closer to the pole. Am i wrong . . .

A line of longitude is a great circle. The yellow track, if I read it right is not a small circle.

The grey track is a rhumb line, ie a line of constant heading that cuts all lines of longitude at a constant angle.

[sterion75]

I just read that inmarsat said the altitude didnt change and it was 30,000+ constant(bbc)

[cockpitvisit]

Originally Posted by awblain

Neither the distance change away from the satellite between the hourly pings nor any potential Doppler information would by itself rule out a Northern location,

From what I understood, the Doppler shift of interest was caused not by the aircraft movement, but by the slight movement of the satellite itself. So if the frequency increases when the satellite is moving "south", it means the airplane is in the Southern hemisphere.

But it could as well be a cover for a leak from spysats.

[RiSq]

I think a lot more info will come out over the next few days. It seems odd to me that they would announce it at this hour, if they didn't have additional info to back it up.

My hunch is that the crews went out with this "New info" today (local time) and found the wreckage, but details not released until they have a ship on the scene.

We know for certain that there has been a delay with all info, so the fact they announced it at this hour has me believe they have wreckage located that could only be from MH370.

Anyone else of same opinion?

Ps. Regards to fire, have they not confirmed the previously reported irratic altitude changes which had everyone assuming "fire" were incorrect and it held and maintained FL30?

[OleOle]

Pontius Navigator

A line of longitude is a great circle. The yellow track, if I read it right is not a small circle.
The grey track is a rhumb line, ie a line of constant heading that cuts all lines of longitude at a constant angle.

I understand that the grey line in Richards map represents the great circle. In the Mercator projection lines of constant heading are are straight lines. This case is special because we are getting close to the magnetic south pole where magnetic deviation rises to >30W. That is why the constant magnetic heading line (yellow in Richards map) turns to the east. Without deviation it would be a straight line in this projection.

[RichardC10]

OleOle

thanks for that work and the grasp it gives on the required error margin of the arcs. I would expect the great circle solution to turn to the right (west) when getting closer to the pole. Am i wrong or is the turn just too slight to see?

When going west over Malacca Strait in the first part of the track the a/c was heading always directly towards the satellite. Maybe from this part of the track inmarsat could put more constraints on speed.

Wind drift would also play a significant role.

The differences between a great circle and rhumb line are small for a track that is largely South and at these latitudes, and are hard to see at this scale. I looked at great circle, rhumb line and the constant magnetic bearing courses.

As you say, the final turning point to the Southly heading is not known and it might come out from analysis of the early ping data. Wind drift would be significant but would be the same for all tracks in roughly the same area so would not be a differentiator between the options, I think. Winds would be different on the possible North and South routes and could be one of the things that was used to rule out the Northly route.

[Dumbo Jet]

cockpitvisit

Thanks for the insight there. Couldn't work out how the doppler effect would help - but of course the satellite is also moving. Makes perfect sense now!

[RatherBeFlying]

Kudos to Inmarsat and AAIB

If it hadn't been for Inmarsat, we'd still be looking from Somalia to Siberia.

And a very well done to the partnership with AAIB for resolving the ambiguity between arcs. There was some seriously caffeinated data crunching going on

Hopefully GPS location will be added to the ping ID. It won't stop suicides, but will give pause to those who thinking they can sneak off. With GPS data, any diverters will not be able to hide.

While in too many cases survivors will be unlikely, at least families will not be left in limbo -- to say nothing of the massive expenditures in search effort.

[Golf-Mike-Mike]

Originally Posted by awblain

Richard, Under similar assumptions does that rule out the Northern route? I assume that must require a weird combination of speed and track changes to remain consistent with the timings.
Neither the distance change away from the satellite between the hourly pings nor any potential Doppler information would by itself rule out a Northern location, any better than reasonable assumptions about the aircraft being spotted enroute ruled it out a week ago. It's also not really clear why today's news, if the better Inmarsat analysis is all there's been, merits the appearance of the Malaysian PM or the move of the victims' families to Perth.

Because INMARSAT have also reviewed the pings from other Malaysian 777s that flew northerly routes and their doppler signature was different to that received from MH370. As that rules out a northerly track it places the missing aircraft in the southern Indian Ocean, without a landing site anywhere near, and hence the need to tell the families that there is now no hope of survival.

[ edit to add this, from BBC - Engineers spent all weekend looking back at previous Malaysian Airlines Boeing 777 flights, going back several weeks.
They compared the satellite data from those flights with flight MH370 and were able to work out it went south.
This is cutting-edge modelling, never tried before. It uses the Doppler effect - which is what makes a police siren sound different from different points.
They had it reviewed by other scientists before handing it over.
As far as they can tell, the plane was flying at cruising height, above 30,000ft. They found no evidence of fluctuating heights being reported.
This is it now - they cannot pinpoint the position any further. They handed this data over on Sunday morning. ]

[AndyJS]

The latest estimates seem to indicate that the plane may have flown over Indonesian airspace. But they didn't notice?

[NigelOnDraft]

Hopefully GPS location will be added to the ping ID. It won't stop suicides, but will give pause to those who thinking they can sneak off. With GPS data, any diverters will not be able to hide.

While in too many cases survivors will be unlikely, at least families will not be left in limbo -- to say nothing of the massive expenditures in search effort

Not too sure about this I'm afraid. This accident has ensured any future plan will involve isolating the Satcom units themselves as well, not just the protocols that use it.

[G0ULI]

Excellent work by the AAIB. So we now know the aircraft flew at steady speed and altitude until the fuel ran out in the Southern Indian Ocean. That should at least put paid to all the posts relating to Lithium battery fires, flying under the radar and deliberate attempts to kill everyone by hypoxia/anoxia. The most obvious conclusion is that someone was in control of the plane until it crashed. Clearly the anti hijack door functioned exactly as advertised and prevented anyone from entering the cockpit once the course to the Southern Indian Ocean had been set. A tribute to the cockpit security system installed on this aircraft.

[Dumbo Jet]

G0ULI

I'm sorry but how do you KNOW that? Would be interested to know your factual evidence for that!

[DAL208]

From memory, the southern 'arc' started to the south of the last known position of the aircraft. Is it not possible the aircraft didn't turn left over malaysia at all and just went South from its last known position? Could the primary RADAR contact be completely different aircraft? How certain are we it turned left and went over straits of malacca?

[funfly]

BBC reported said (1830) that he asked the spokesman if there was any more information on the cause and the reply was that they had some additional information but were not ready to announce it.