let's begin with our aviation correspondent rene marsh with the very latest. rene? >> a sudden shift in focus. again, this search zone has moved and authorities say that's thanks to a credible lead. that lead? more analysis of existing data with an entirely new search zone in play, does that mean crews wasted time searching the wrong area for more than a week? the new zone, roughly 1,023 square miles, larger than the state of new york and 300 miles closer to the australian coastline a shorter trip for search planes. >> this is our best estimate of the area in which the aircraft is likely to have crashed into the ocean. >> reporter: so why change everything three weeks after the plane disappeared? more radar and satellite analysis makes investigators believe the plane was flying faster than previously thought. as it moved between the south china sea and the strait of malacca.