Search nearly done of area where Malaysia Airlines jet likely went down

Sydney: The unmanned submersible scouring the ocean floor for wreckage from Malaysia Airlines Flight 370 is nearing the end of its underwater search, having covered 80 percent of an area authorities believe to be the most likely resting place of the plane and its 239 passengers.

The Bluefin-21, on its ninth mission Tuesday, was searching an area of the Indian Ocean about 1,000 miles northwest of Perth, the capital of Western Australia. The agency coordinating the search said the underwater zone is defined as a circle with a 6.2-mile radius around the last acoustic signal detected on April 8.

The searches began after the Australian naval vessel Ocean Shield picked up four acoustic signals, two on April 5 and two more on April 8, using a towed pinger locator. At that time, the plane had been missing for a month after veering off course on March 8 on a routine flight between Kuala Lumpur, Malaysia, and Beijing.

"Bluefin-21 has now completed more than 80 percent of the focused underwater search area and further missions are planned," the Joint Agency Coordination Center said in an email. "It is important this lead is pursued to its completion so we can either confirm or discount the focused underwater area as the final resting place of MH370."

So far, no debris that can be identified as linked to the aircraft has been found, and the Bluefin has not recorded any data that shows promise in finding any wreckage.

Bad weather resulted in an interruption to the aerial search Tuesday as Tropical Cyclone Jack headed southeast toward the search zone. The agency said 10 ships remained in the area, and five planes had left Pearce air base near Perth before the search was halted, but a further five would remain grounded for the day.

The Joint Agency Coordination Center said in a separate email that "if we don't find the wreckage, we will then stop, regroup and reconsider." But there has been no word on whether authorities have called for deep-sea equipment with greater capabilities, or if other methods would be used to better calculate where the plane may have gone into the ocean. Australian authorities believe the plane could be sitting in silt, as much as 15,000 feet down into the ocean - a depth that has already tested the capabilities of the Bluefin-21.

"The search will continue," the agency said in an email Tuesday. "We are currently consulting very closely with our international partners on the best way to effect this for the future."