Pings at heart of MH370 hunt not likely from black box

In a file picture taken on May 5, 2014 Able Seaman Matthew Tranter-Edwards (left) walking past the Phoenix Autonomous Underwater Vehicle

SYDNEY, May 28, 2014 (AFP) - Four acoustic transmissions that have been the focus of the search for missing Malaysia Airlines Flight 370 are no longer believed to have come from the plane's black box, a US navy official said Thursday.

The Navy's deputy director of ocean engineering Michael Dean told CNN there was now broad agreement that they came from some other man-made source unrelated to the jet that disappeared on March 8 carrying 239 people.