The search operation for the missing Malaysia Airlines Flight MH370 has entered a new phase. Officials now say they're ready to deploy an underwater vehicle to search the ocean floor for wreckage, amid concerns that the black boxes' batteries have run out.

The Bluefin-21 will search the sea floor for wreckage from flight MH370.?

Thirty-eight days and counting, military and civilian aircrafts, and some of the world's most sophisticated ships continue to scour the Indian Ocean for any sign of the missing Malaysia airliner MH 370.

The best lead searchers have had so far have been pings detected by search aircrafts and vessels and are believed to be from black boxes. But they haven't detected any since last Tuesday. Now that could very well be because the black boxes' batteries have already expired. They're supposed to last only for 30 days, or 40 at best.

"Analysis of the four signals has allowed the provisional definition of a reduced and manageable search area on the ocean floor. The experts have therefore determined that the Australian defense vessel Ocean Shield will cease searching with the towed pinger locator later today and deploy the autonomous underwater vehicle Bluefin 21 as soon as possible." Angus Houston, head of Joint Agency Coordination Center, said.

The U.S. Navy's underwater drone is capable of sweeping the ocean floor to a depth of up to 4,500 meters, but officials and experts warn the task will be far from easy.

"This is a very slow process. It's a very laborious process. A lot of patience, a lot of will, a lot of money is required to painstakingly crisscross the ocean bed at almost just a walking pace. We also don't have a very good map of the bottom either. We know it's silt, 20 meters of silt on the bottom. They could be one or two meters down in the silt, so finding them could be exceedingly difficult." Aviation analyst Geoffrey Thomas said.

There is, however, potential new evidence that the current search area may indeed be the final resting place of MH370.

An oil slick; just over 5,000 meters from where electronic signals were last detected; had been found, a sample of which has been taken for further analysis.

Still, Air Chief Marshal Houston cautioned against raising any hope or expectation until there is visual confirmation of the wreckage or any debris from Flight MH 370.