The search for Malaysia Airlines flight MH370 in an area of the southern Indian Ocean where acoustic signals were detected in early April has been in vain, the Joint Agency Coordination Centre (JACC) said in a statement today.

The JACC said that the Bluefin-21 autonomous underwater vehicle completed its last mission yesterday, and after having scoured over 850 square kilometres of the ocean floor had found no sign of the missing aircraft.

"The data collected on yesterday’s mission has been analysed. As a result, the JACC can advise that no signs of aircraft debris have been found by the autonomous underwater vehicle since it joined the search effort.

"With that, the Australian Transport Safety Bureau (ATSB) has advised that the search in the vicinity of the acoustic detections can now be considered complete and in its professional judgement, the area can now be discounted as the final resting place of MH370."

The HMAS Ocean Shield, the main vessel used in search operations since the indication that the flight MH370 "ended its journey in the southern Indian Ocean", has also departed the search area as of last night and is expected to arrive at Fleet Base West near Perth on Saturday.

The JACC statement reiterated that the search for the missing Boeing 777-200 continues and will involve three major stages:

- reviewing all existing information and analysis to define a search zone of up to 60,000 square kilometres along the arc in the southern Indian Ocean;

- conducting a bathymetric survey to map the sea floor in the defined search area; and

- acquiring the specialist services required for a comprehensive search of the sea floor in that area.

"The expert satellite working group continues to review and refine complex analyses of radar and satellite data and aircraft performance data to determine where the aircraft most likely entered the water. The findings of the review will be made public in due course," said the JACC.

The JACC added that three vessels are still covering the wider area considered the likely final resting place of flight MH370.

"The Chinese survey ship Zhu Kezhen is mapping the ocean floor and its operations are supported by another Chinese ship Haixun 01 and the Malaysian vessel Bunga Mas 6.

"The survey data will then be sent to Fremantle, in Western Australia, weekly for further processing by Geoscience Australia. A contracted survey vessel will join the Zhu Kezhen next month.

"The mapping of the ocean floor, which is called a bathymetric survey, is expected to take about three months. Knowing the seafloor terrain is crucial to enabling the subsequent underwater search," the JACC said.

The underwater search will then resume with the aim of locating the aircraft and any evidence such as aircraft debris and flight recorders to assist with the Malaysian investigation on the disappearance of flight MH370.

It is anticipated that this component of the search will begin in August and take up to 12 months.

The JACC also revealed that the ATSB will release a formal request for tender to source the capability to undertake the underwater search, and a single prime contractor will be chosen to bring together and manage the expertise, equipment and vessels in carrying out the search. – May 29, 2014.