Why Did Australia Change the Search Area?

This is happening late at night and will bear further discussion in the morning, but I wanted to get something up online quickly to explain the basic gist of the situation. A little over an hour ago, at 9.30pm EDT here in the US, the Australian government announced that it was abandoning the current search area and moving to a new one 11oo km to the northeast. The reason, they said, is:

The search area for missing Malaysia Airlines flight MH370 has been updated after a new credible lead was provided to the Australian Maritime Safety Authority (AMSA)… The new information is based on continuing analysis of radar data between the South China Sea and the Strait of Malacca before radar contact was lost. It indicated that the aircraft was travelling faster than previously estimated, resulting in increased fuel usage and reducing the possible distance the aircraft travelled south into the Indian Ocean.

This explanation really doesn’t make any sense. I want to quickly explain why, and give some context of where all this is happening geographically.

First, here’s a very crude chart I’ve made on Google Earth showing  the old search area and the new search area (very roughly estimated). You’ll recall that earlier this week Inmarsat released an analysis of its “ping” data that plotted different routes the aircraft might have taken. The upshot was that if the plane was flying at 450 knots, it would have wound up at a spot on the 8.11am ping arc marked “450.” If it had flown at 400 knots, it would have wound up around the spot marked “400.” (click to enlarge)

new search area

 

As you can see, it appears that the old search area assumed a flying speed of a bit more than 450 knots, and the new search area assumes a flying speed of a bit more than 400 knots, with prevailing currents causing debris to drift to the southeast.

The shifting of the search area to the northeast would seem to stand at odds with the assertion of the press release, which implies that new radar analysis finds the plane was flying faster then originally estimated. In fact, it was flying slower than originally estimated.

At any rate, the abandoning of the old search area, after such significant assets had been lavished upon it, raises the question of why they were so confident about it that speed estimate in the first place. And then raises the obvious sequela: Why are they so confident in this one?

BTW, here’s that graphic from the Inmarsat, showing the 450 and 400 knot plots:

Screen Shot 2014-03-27 at 10.48.57 PM

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