Robotic submarine to expand search area for Malaysia Airlines plane

April 26, 2014: One of the relatives of Chinese passengers on board Malaysia Airlines Flight 370 sits underneath a banner written with messages dedicated to passengers on the missing plane during a briefing held by Malaysian officials at a hotel in Beijing, China. (AP Photo/Andy Wong)

CANBERRA, Australia – A robotic submarine scanning the Indian Ocean floor for the missing Malaysia Airlines jet will extend the area of its current search, which will end soon with no clues of the Boeing 777 found yet, authorities said Sunday.

The U.S. Navy's Bluefin 21 has been creating a three-dimensional sonar map of the ocean floor for more than two weeks near where signals consistent with airplane black boxes were heard on April 8.

The search area is a circle with a 10-kilometer (6-mile) radius, 4.5 kilometers (2.8 miles) deep off the west Australian coast.

The sub was expected to complete the focused underwater search area and continue examining the areas adjacent to it, the search coordination center said in a statement. The sub spends four hours traveling to and from the sea bed, and 16 hours searching the ocean floor. It takes another four hours to download data from each search.

Australian Defense Minister David Johnston said last week that an announcement was likely this week on the next phase of the search for the jetliner that vanished with 239 passengers and crew -- mostly Chinese -- on board on March 8 during a flight from Kuala Lumpur to Beijing.

He said the next phase was likely to deploy more powerful side-scan sonar equipment that can delve deeper than the Bluefin 21.

The search center headquartered in the Australian west coast city of Perth said a daily air search for debris northwest of Perth was suspended Sunday because of deteriorating weather.