It’s Day 31 of the search for missing Malaysian Airlines Flight MH370, which disappeared in the early morning with 239 people on board, including six Australians.  Right now, ships and planes are trying to home in on the pulses first detected earlier by a Chinese ship, hoping that the signal is from the missing plane’s flight data recorders.

The Chinese naval ship Haixun 01 detected several “acoustic pings” at a location on Friday, and the UK Royal navy HMS Echo is en route to assist the Haixun 01, which was actually outside the three search zones when the detection occurred.  Australia’s ADV Ocean Shield is 550 kilometers away, investigating its own experience with a pulsing tone eerily similar to that emitted from “black box” flight data and voice recorders.

PM Tony Abbott, in Japan for trade talks, echoed the earlier admonition from Air Chief Angus Houston, who had said, “This is an important and encouraging lead but one which I urge you to continue to treat carefully.”

The batteries that power the black boxes start to wear down after a month – right about now.  If they’re going to find the boxes via the audible “ping” signal, it’s going to have to be in the next couple of days.