Sydney, March 31 (IANS/EFE): Chances of finding the black boxes containing data that would presumably clear up the mystery of flight MH370 are dropping with every passing day, US military officers said Sunday.

The plane disappeared earlier this month in the Indian Ocean.

US Navy Capt. Mark Matthews said that it will be practically impossible to locate the black boxes, the "beepers" on which have a battery life of 30-45 days, before the batteries die somewhere in the area of 319,000 square km where the plane is being sought.

"Everything depends on how effectively we're reducing the search area," Matthews, who participated in the search for Air France flight 447, which crashed in the Pacific Ocean in 2009, told the Sydney Morning Herald.

Malaysia Airlines flight MH370 left Kuala Lumpur March 8 at 12.41 a.m. and was scheduled to land in Beijing roughly six hours later. But it disappeared from radar screens less than an hour after takeoff.

Flight MH370 - carrying 227 passengers, most of them Chinese, and a crew of 12 Malaysians - had enough fuel to fly for 7.5 hours.

On Sunday, the Australian vessel Ocean Shield, equipped with a black box detector and an unmanned submarine vehicle, set sail from the southwestern Australian city of Perth and is expected to arrive in the search zone in three days.

Twenty-four days have passed since the Boeing 777 belonging to Malaysian Airlines disappeared.

Meanwhile, Australian authorities confirmed that the objects recovered Saturday from the waters off their country's western coast do not belong to the vanished aircraft.