CANBERRA, May 31 -- The Chinese survey ship Zhu Kezhen which is conducting the mapping of the sea floor in the Southern Indian Ocean is heading back to the port of Fremantle near Perth in Western Australia, said the Joint Agency of Coordination Center (JACC) for the search of Malaysian airline flight MH370 on Saturday.

JACC said in a statement that Zhu Kezhen suffered a defect to its multibeam echosounder and is coming into port to conduct the necessary repairs.

The journey is expected to take a couple of days.

The bathymetric survey that Zhu Kezhen is conducting is expected to take about three months. It is one of the three stages for future search of the ill-fated aircraft which went missing on March 8 with 239 people onboard.

"Knowing the seafloor terrain is crucial to enabling the subsequent underwater search," JACC said in a statement on Thursday.

The other two aspects will be reviewing all existing information and analysis to define a search zone, and acquiring the specialist services to conduct comprehensive underwater search.

An Australian contracted survey vessel will also be involved in conducting the bathymetric survey and will arrive in the search area in June.

JACC announced on Thursday that the autonomous underwater vehicle Bluefin-21 wrapped up its search mission with an empty hand and the search area was discounted as the final resting place of the aircraft.