Huge Search Day Begins For Flight 370

(Perth) -- One of the largest days of searching yet is underway for the missing Malaysia Airlines jet. More than a dozen planes and nearly a dozen ships are scouring an area of the South Indian Ocean today in search of any clues to the disappearance of Flight 370. The hunt for the plane's black box is going underwater. Searchers are using a giant underwater microphone that listens for pings from the plane's flight data recorders. They're also using an underwater robot that scans the ocean floor for signs of wreckage. It's been four weeks since Malaysia Airlines Flight 370 vanished on a flight from Kuala Lumpur to Beijing.