Underwater search for Malaysia Airlines flight resumes

The Malaysian-contracted GO Phoenix began its search for the vanished airliner on Monday, far off the western coast of Australia. The ship will spend 12 days looking for MH370 before returning to shore to refuel.

"The vessel GO Phoenix, with equipment and experts provided by Phoenix International, has arrived in the search area in the southern Indian Ocean, and commenced underwater search operations," the Australian Transport Safety Bureau, the agency leading the search, said in a statement.

Searching the 'seventh arc'

The search was put on hold for four months so that the seabed in the 60,000-square kilometer (23,000-square mile) search zone, which lies around 1,800 kilometers west of Australia, could be mapped.

MH370 disappeared on March 8 while en route from Kuala Lumpur to Beijing. By analyzing the plane's satellite transmissions, investigators believe the aircraft ran out of fuel and crashed in the "seventh arc" stretch of the southern Indian Ocean.

"We are confident in the analysis and we're confident that the aircraft is close to the seventh arc," said ATSB Chief Commissioner Martin Dolan.

Sonar device employed

Two other ships provided by Dutch contractor Fugro are to join the GO Phoenix later this month.

The vessels will use a sonar device called the towfish that is dragged around 100 meters (330 feet) above the seabed to search for the Boeing 777-200 wreckage. The towfish can detect the presence of jet fuel in the water, and is designed to operate in the extreme depths of the area, which can reach up to 6.5 kilometers in some spots.

If something of interest is detected, the ships' crews will attach a video camera to the towfish.

Despite the huge air and sea searches already carried out, which included a more-targeted underwater probe, no sign of MH370 has ever been found.

dr/av (AP, AFP)