Search crews have heard nothing further from whatever was sending possible pings that might be linked to missing Malaysia Airlines Flight MH370, search leaders said Tuesday.
Fourteen ships and 14 aircraft were back out over the Indian Ocean, scouring a narrower area — this one about 30,000 square miles 1,400 miles northwest of the Australian port of Perth — for signs of the plane that disappeared March 8 with 239 people aboard.
The search area shrank after a pinger locator on an Australian ship detected signals consistent with transmissions from aircraft black boxes, officials had said Monday in what they called their most promising lead yet.
Australian Defense Minister David Johnston agreed at a news conference Tuesday morning that "this is the most positive lead."
"Rest assured we are pursuing it most vigorously," he said.
But "this an herculean task," he said. "It's over a very, very wide area. The water is extremely deep."
"We have several days of intense action ahead of us," he said.
Retired Australian Air Chief Marshal Angus Houston, who's in charge of the overall search, joined Johnston at the news conference and said: "There's still a lot of doubt out there, but I am a lot more optimistic than I was one week ago."