A Chinese sonar-equipped vessel, which was recently contracted to assist in the search for missing Malaysia Airlines Flight MH370, is set to leave Australia for its first of three operations in the search area. The news comes as the search for the missing Boeing 777-200 enters its final phase before efforts are called off in June.

Australia’s Joint Agency Coordination Centre said in its latest search update that Chinese vessel Dong Hai Jiu 101 has been testing its Synthetic Aperture Sonar off the west Australian coast in recent days and will drop off personnel, who were embarked only for trials, at the port of Fremantle before departing Thursday for the search area in the southern Indian Ocean.

Three other vessels have been scouring 46,330 square miles of the ocean floor to locate Flight MH370, which went missing on March 8, 2014, with 239 people on board while on its way from Kuala Lumpur to Beijing.

So far, the first and only piece of physical evidence to be recovered from the plane is a flaperon that washed ashore on France's Réunion Island in the Indian Ocean — about 2,300 miles away from the current search area — in July 2015. The multimillion-dollar search for the plane has yielded no concrete clues so far.

On Tuesday, Martin Dolan, head of the Australian Transport Safety Bureau, which is leading the hunt for Flight MH370, said that there is “a possibility” that the search for the missing plane “will not succeed.” Dolan also reportedly said that they are concerned that the search vessels may have missed the plane, which is believed to be resting on the floor of the southern Indian Ocean.

Malaysia is reportedly expected to release a report on the second anniversary of the plane’s disappearance on March 8.