Time, batteries running out on black box

Malaysian and Australian authorities are seeking to inject new momentum into the search for Malaysia Airlines Flight MH370 and its "black box" flight recorder before the batteries in their locator beacons run out.  [Special coverage]

The UK military submarine "HMS Tireless" and survey ship "HMS Echo" have arrived in the southern Indian Ocean to assist in the search for the plane and the "black box". The Echo is fitted with sensors and side-scanning sonar, which may help pinpoint signals from the flight recorders.

Australia's navy vessel Ocean Shield is also expected to arrive at the search area today. It is equipped with special technology designed to detect the pings from the flight recorders, and an underwater robot that can search the ocean bed for signs of wreckage.

But the two pieces of equipment can only work after the location of the plane is identified. The battery life of the black box is roughly 30 days, which means the locator beacon may run out in three days.