China Searchers Note Unidentified Signal Amid Plane Hunt

Crews hunting for the missing Malaysian airliner extended the search to beneath the surface of the Indian Ocean, listening for pings from beacons on the plane’s black boxes before the onboard batteries fail.

A Chinese patrol ship detected a pulse signal with a frequency of 37.5 kilohertz while searching in the southern Indian Ocean and hasn’t established whether it’s from the jet, the official Xinhua News Agency reported today. Underwater locator beacons transmit at that frequency. An Australian ship towing U.S. Navy sensors and a British vessel are also listening for pings from beacons on the black boxes.