04 May 2014: an equidistant location from three centres
In previous updates several different hypotheses were considered, ranging from a northerly path leading to Tibet to a southerly path ending in the Indian Ocean, near the current search area where an Inmarsat's final ping ring intersects an acoustic ring (or a hyperbola) defined by acoustic measurements possibly detected at Cape Leeuwin hydroacoustic station.
In this update we bring to attention radar coverage areas of Australian RAAF which collectively define a very peculiar pattern for a flight path that minimises radar detection.
More precisely, in an attempt to find some logic for a southerly path possibly taken by MH370, leading to a location close to the current search area, the following material is used: a monograph by Dr Carlo Kopp, entitled "Basing Infrastructure Considerations in the Defence of Australia's Indian Ocean Approaches". It is dated 25th February 2012, and the web page where it can be found was last updated on Mon Jan 27 11:18:09 UTC 2014.
The text is interesting in its own right, but one image, reproduced here for convenience, is particularly curious:
Three radar coverage zones / combat radius envelopes are of specific interest: those centred at RAAF Learmonth, Christmas Island, and Cocos Islands. The concentric rings around these three locations define gradients of detection. If one wants to minimise radar detection while flying in the general southerly direction which has been under consideration lately, a single path appears quite clearly (its segment is marked by a red curve below):
Most strikingly, it leads to a location approximated by the following coordinates: (20.03S, 103.43E) - this point is equidistant from all three centres: at RAAF Learmonth, Christmas Island, and Cocos Islands. It is also very close to the location of the current search area.
It is not categorically suggested that the crash site may have these coordinates. However, this is likely, as anyone controlling the flight may have had some access to these or similar publically available images of radar coverage, and so may have planned to minimise detection during the flight.