05 May 2014: suggesting new search area centred at (20.00 S, 103.45 E)
This is a brief update elaborating on yesterday's observation that the current search area is fairly close to a location which is equidistant from three centres with radar capabilities: RAAF Learmonth, Christmas Island, and Cocos Islands.
1. Ping ring + acoustic bearing (search area logic).
First of all, it needs pointing out that with new Inmarsat data on satellite elevation angles, the ping rings were recalculated slightly reducing in radii. In particular, the final (partial) ping ring is around 90-100 km smaller in radius. The following Google Earth snapshot shows the old ping ring (a white arc), as well as an acoustic bearing from Cape Leeuwin (a red line) which has been hypothesised to identify the current search area.
The line of the acoustic bearing can be extended further to intersect with the new Inmarsat ping ring, corrected due to modified elevation angle. The corrected ring is not shown, but the new search area is marked by a small circle, centred at approximately (20.00 S, 103.45 E).
2. Equidistant location from three centres (possible motivation).
Secondly, let's turn attention back to the location which is equidistant from three centres with radar capabilities: RAAF Learmonth, Christmas Island, and Cocos Islands. Adding three circles, with radius of 600 nmi = 690.47 miles, around these three locations, to the previous image results in the following Google Earth snapshot:
It can be seen easily that the equidistant location is one and the same as the small circle identified by the intersection of the (hypothesised) acoustic bearing and the new Inmarsat ping ring. This may be a coincidence, but if not, it may provide a reason why the flight path ended up not just in a middle of nowhere, but rather in a point that has some logic.
3. Zooming in.
Regardless of what motivation may have been behind the choice of this terminal location by people in control of the plane (if indeed it was controlled by people and not an autopilot), the corrected search area deserves a closer look:
The snapshot above shows the suggested new search area centred around a point with coordinates (20.00 S, 103.45 E), and a radius of about 30 km. This new area is about 100 km north-west from the current search area.