PERTH, Australia (CBS News) -- U.S. Navy equipment has picked up
signals consistent with the pings from aircraft black boxes, an
Australian search official said Monday, describing the discovery
as "a most promising lead" in the month-long hunt for the
missing Malaysia Airlines plane.  Angus Houston, the head of a
joint agency coordinating the search in the southern Indian
Ocean, called it "very encouraging" but warned it may take days
to confirm whether signals picked up by the ship Ocean Shield
are indeed from the flight recorders on Flight 370.  "Clearly,
this is a most promising lead, and probably in the search so
far, it's the probably the best information that we have had,"
Houston said at a news conference.    He said the position of
the noise needs to be further refined, and then an underwater
autonomous vehicle can be sent in to investigate.   The Ocean
Shield was continuing to comb the area to try pick up the
signals again, Houston said.  After a month-long hunt for
answers filled with dead ends, Mon