PERTH, Australia, April 4 (UPI) -- The underwater search for emissions from the black box pinger from Malaysia Airlines Flight 370 began Friday as Australian and British vessels combed a 240-kilometer track in the southern Indian Ocean.
On March 30, the U.S. Navy loaded a Towed Pinger Locator and a submersible onto Australian defense vessel Ocean Shield. The Ocean Shield was joined this week by Royal Navy hydrographic survey ship HMS Echo, which is also equipped with "advanced environmental assessment capability" to scan the ocean surface for the MH370's black box transponder.