The search for AirAsia plane that crashed into the Java Sea on its way from Surabaya in Indonesia to Singapore last Sunday is set to move underwater with the arrival of specialist equipment, a media report said .

A French crash investigation team will use sensitive acoustic detection devices to try locate the flight QZ8501’s black box, BBC reported.

The Airbus A320-200 aircraft with 155 passengers and seven crew members on board went missing soon after taking off from Surabaya. The debris was spotted Tuesday.

No survivor has been found and the cause of the crash remains unknown.

So far, only eight bodies have been found and brought ashore, with the search operation repeatedly held up by bad weather and rough seas.

One body, identified as that of passenger Hayati Lutfiah Hamid, was buried in Surabaya at an Islamic ceremony attended by relatives and neighbours Thursday.

The plane is almost certainly at the bottom of the Java Sea. Though several pieces of debris, includign an exit door, have been recovered, despite a massive five-day search, the fuselage is still missing. Officials say most of the passengers could still be inside.

The “most probable area” for search of the missing AirAsia flight has been demarcated, Royal Malaysian Navy Chief Abdul Aziz Jaafar said Friday.

He said the search area was established with a dimension of 1,575 sq nautical miles, Xinhua reported citing a tweet by the navy chief.

“This is most likely the area of the missing plane,” he added, posting an image mapping out the search area.