Melbourne, Oct 6 (PTI) A new phase of the multimillion dollar search for the missing Malaysia Airlines Flight MH370 began today in a refined zone in the remote Indian Ocean after a long pause, in a last ditch-effort to solve the greatest aviation mystery.

The underwater search for the Boeing 777 which vanished on March 8 along with 239 people, including five Indians, began in an area about 1,800 km off Australia’s west coast after a vessel fitted with specialist underwater equipment reached the zone last night.

The Malaysian-contracted GO Phoenix vessel has begun scanning the ocean floor for the plane, said Australian Transport Safety Bureau (ATSB) said.

The vessel began to scour the ocean floor with sonar and video, according to an ABC report. The device is said to have the ability to identify traces of jet fuel.

The 60,000-square kilometer search area lies along what is known as the “seventh arc” a stretch of ocean where investigators believe the aircraft ran out of fuel and crashed, based largely on an analysis of transmissions between the plane and a satellite.

Until now experts have concentrated on mapping the seabed in the southern Indian Ocean search zone where the ill-fated plane is believed to have doomed in March.

ATSB’s chief commissioner Martin Dolan said the search in the refined zone could last for up to an year.

“What we have is a plan to cover the high priority areas, (but) we don’t really have any sense of when in the course of that year we’re likely to find something,” he said.

Searchers are hoping to answer what has become one of the greatest mysteries in aviation history.

“All we want to indicate to everyone is we are cautiously optimistic in the course of a year we’ll locate the missing aircraft,” Dolan said.

There is AUD60 million (USD 52.8 mn) earmarked by the Australian government for mapping and underwater search; and Australian expenditure is to be matched by Malaysian government.

The search operation, described by Australian officials as the largest in history, has so far turned up no debris from the plane.