The altitude excursion data was attributed to leaked Malaysian PSR returns on the unidentified target (presumed MH370) at IGARI sometime shortly after transponder switched off.

What would be good is if we had the intermediate ping details & times....

Using the 40 degree arc, it does put it a long way away, especially if India did not see it.

Relatively untraceable communications with ground-based collaborators
 

If there is a conspiracy involving collaborators on the ground, it has already been pointed out that satellite phone contact would probably work from inside the plane, especially near a window. A small hand-held VHF set would be problematic and give very restricted reliable range of miles or tens of miles unless you were lucky.

Whilst the use of a satellite phone would leave you open to eventually being tracked / triangulated that would almost certainly take days to occur as the satellite operators would have no particular reason to suspect that any given call was even remotely related to the missing aircraft.

From the flight deck, as may well be the case, HF radio would probably be your best bet. Picking a suitable channel, you are highly unlikely to be overheard and HF is notoriously hard to triangulate unless significant assets are coordinated and expecting your transmissions. This would give a potential reliable range of one or two thousand miles, coupled maybe with a switch to VHF when in closer range. It's easy to overestimate the SIGINT resources that are out there and kid yourself that 'everything is monitored' but it's vastly more likely that that is simply not true. And even if it were true, your goals have probably been accomplished long, long before anyone realises that a couple of random / unexpected transmissions were you and joins up the dots.

Simple portable HF stations are ridiculously easy to set up as anyone with a comms background (as I have myself) will know, ditto VHF. It can all be operated from the back of a truck and put together for a few hundred dollars.

Pace ...More likely this was a case of massive depressurisation.

I heard on the news conference that systems were switched off / deactivated at different times, pointing to the fact they were deliberately turned off.

That would be 2 radios transmitting data, transponder, CPDLC, SAT, ADS etc..

If the aircraft was deviated from its route intentionally, and then as suggested flown in close proximity to another aircraft to avoid detection the satellite pings that have been recorded could be traced to other transponding aircraft on the same route, military primary radar traces could then be observed for a target break away and a possible new route calculated.

North & South Arc
 

Why have they not filled in the arc between the north & south arc. Would this not also be a possible location for the final 8:11am ping?

Regardless if the cabin crew used portable oxy or not given the threat was at the controls it would have been just as easy to eliminate the cabin crew.

Thanks jimjim and stormy

It is very clear to me from the photo of the Malaysian SAR map

https://pbs.twimg.com/media/BiwPWMOCYAAG3ZC.jpg:large

cross referenced with the INMARSAT coverage map

http://www.inmarsat.com/wp-content/u...ember-2013.jpg

that they are doing the calculations on the basis of of only one INMARSAT being in contact with the plane (at the end).

Only the Indian Ocean (64E) INMARSAT was involved in the last ping(s) and so they have ruled out areas (on the 40 degree circle) that overlap with coverage by POR in the Pacific and AOR-E over the Atlantic to the West.

As a captain, if he didn't know how to do that already then it would be a scary ride alongside him.


We may never know what happened on board this plane. If somebody can switch off the ACARS and Transponder then they may have the ability to switch off the CVR and FDR.

The Indian Ocean is a pretty big dumping ground and would need some sort off debris to identify a place to start searching.

I still reckon we are not being told the whole picture of what the authorities know, but if keeping quiet, means the possibility of getting back "hostages" then they have to do it.

I think the use of the term arc is possibly better that corridor. The two arcs, if I have understood correctly, are the result of "triangulating" data captured by two satelites using time codes. What is not clear is whether the last "ping" cannot be precisely positioned on these arcs which then possibly means that they are indeed corridors (i.e. arcs with a width corresponding to precision, with the points sighted being the limits of accuracy at say 2 std deviations.

Assuming the aircraft was flying in a roughly constant direction, I suggest that the actual last position can be estimated with a further arc being when the a/c ran out of fuel or landed and was shut-down, which clearly must have been around or after 00:11Z. This suggests it could well be towards the western end of the northern corridor.

the speculation is now back on a possible terrorist act, but making an aircraft disappear without spectacle doesn't seem to be the MO for radical terrorists.

Good question and one investigators should looking into.

From a purely legal angle, this incident is still in limbo as there is technically not yet an "accident" to investgate. ICAO gives primary responsibility for an accident investigation to the country in whose territory the aircraft came down in with "party to" rights guaranteed to the nations of registry and manufacture. If the incident occurred in international waters, primary investigatory responsibility is on the nation of aircraft registry with party to the investigation rights guaranteed to the nation of aircraft manufacture. From that perspective, the only two nations guaranteed to be part of the investigation are the US and Malaysia. Unfortunately, the latest satellite telemetry has caused even greater uncertainty over the issue of which nation will have primary responsibility for conducting the investigation. Moreover, it is not altogether clear that there has been an accident. KUL-ALA/UUAA (Almaty, Kazakhstan) was well within the range of the aircraft as fuelled. Until there is wreckage found, this matter will remain in limbo.

Cheers that does explain it. Although on my original map, the gap is not symmetrical around the equator as I would have expected.

In theory, yes. The phone may try to perform a location update, especially if it senses a new network such as at a border crossing. But (and referring to e g China Mobile statements) if the location update request fails the home country network will probably not be notified. Most such requests probably fail due to weak radio connection.

In this case there may be a trace recorded in the visited network's database. But since such unsuccessful requests are from the visited network's viewpoint just nuisance data taking up storage space, it is doubtful if it's stored for any length of time. Network operators probably will not make public exactly how this works in each network, but it is conceivable that the accident investigators can be allowed to sift through this data if it exists.

ana1963

Ping return time to satellite is a known speed therefore distance can be calculated.

The two "corridors" are defined as follows.

Draw a circle on the earth with centre 64 degrees East on the equator and radius 4840 km as measured on the earth's surface.

(This is the 40 degree circle from satellite IOR).

Then erase those parts of the circle which are under the coverage of satellites POR (to the east) and AOR=E (to the West).

See coverage map here
http://www.inmarsat.com/wp-content/u...ember-2013.jpg

This will leave you with the two arcs marked red on the Malaysian map.

"If they can lose a 777, it doesn't bode well for them picking up a bomb laden hostile fighter."

And we all know who lost FOUR medium jets in their backyard at the start of this millennium, don't we???!!!!

The sheer and utter arrogance leaves me bemused if not slightly annoyed!!!:ugh:

Possible alternative
 

Not sure if this is possible (only fly domestically) if this was well planned, couldn't the pilot/hijacker have already entered a flight plan into the system earlier that day, then when at the cross over from one FIA to another, turn off the xpndr, change course and altitude, then fly along for a bit (with all other communication turned off) then at another FIA boundary call along the lines of "xxx centre, this is embraer 107 at FL290 for xxx, we are experiencing xpndr issues..." The controller looks up the flight plan and pilot flies along giving position reports etc under the previously entered flight plan call sign? Would the new controller check with the previous region? The best way to hide a tree is in a forest, they simply became another flight with a malfunctioning xpndr (unless they can mod the hex code or just run mode c) and proceed normally. What other flight plans or flights just happened to be going the same direction on the same day and time?
As good a theory as any or completely off the mark?

Going back to reports of mobile phones ringing - maybe that was when the aircraft was still airbourne, over land and after it was overdue at destination?

They can't (Easily) do that BUT the CVR only records 2 hours and the DFDR may simply tell us, roughly, what we already know.

So we may never get to the facts of what actually happened and why??