An international team hunting for the missing Malaysian passenger jet is trawling the last third of a search zone for wreckage after an unmanned submarine failed to find traces of the aircraft.

The Bluefin-21, which bounces sound waves off the Indian Ocean floor to create images of the seabed, has scoured two- thirds of the targeted area without establishing any “contacts of interest,” according to the Australian agency coordinating the effort. The submarine is currently completing its ninth mission, the Joint Agency Coordination Centre said in an e- mailed statement today.

The search by planes for wreckage was suspended because of poor weather conditions in the area as a result of Tropical Cyclone Jack, the JACC said in a separate statement. Ten ships will continue scouring about 49,491 square kilometers of ocean off the coast of Western Australia today for debris from the aircraft, which went missing March 8 with 239 people on board.

The dives are within a 10-kilometer (6-mile) radius of where audio signals were detected on April 8. No pulses have been heard since then and authorities say the batteries in the aircraft’s black boxes have probably expired.

No physical trace of the Malaysian Airline System Bhd. jet has been found as the search enters its 46th day — the longest hunt for a missing passenger plane in modern aviation history.

Total Blank

Search crews hunting for the wreck may need to review the area of focus again because the absence of any surface debris suggests the correct location has still not been identified, the German oceanographer who helped find the remains of Air France 447, said last week.

The optimism injected into the search after pinger signals were picked up may also prove ill-founded because the sounds could have come from sources other than the emergency beacons, said Peter Herzig, executive director of the Geomar Helmholtz Center for Oceanographic Research in Kiel, Germany.

With all the planes and ships combing the Indian ocean for signs of debris, it’s unusual to draw a total blank, Herzig said. Given that the force of an aircraft hitting the ocean is similar to collision with concrete, this should leave at least some debris floating, as was in the case with the Air France 447 plane en route from Rio to Paris in 2009, he said.

Finding the cockpit-voice and flight-data recorders are key to determining why the Boeing Co. 777-200ER jet vanished. Flight 370’s disappearance has baffled authorities because contact was lost less than an hour into a routine trip to Beijing from Kuala Lumpur.

Police Investigation

The widebody plane vanished from civilian radars while headed north over the Gulf of Thailand, then doubled back and flew over Peninsular Malaysia and on into some of the world’s most remote waters.

While the motive behind that heading remains unknown, MH370 was deliberately steered south on a path ending in the Indian Ocean, Malaysian Prime Minister Najib Razak has said.

Malaysian police are continuing with their investigations and have interviewed 260 people so far, Inspector General of Police Khalid Abu Bakar said in a text message yesterday.

“Investigations are still on-going and nothing can be revealed yet,” he said. “We will investigate as long as it takes to find out what really happened.”

With assistance from Michael Sin in Sydney.

To contact the reporters on this story: Edward Johnson in Sydney at; Manirajan Ramasamy in Kuala Lumpur at; Chong Pooi Koon in Kuala Lumpur at To contact the editors responsible for this story: Anand Krishnamoorthy at Edward Johnson.

Photo Credit: The Phoenix International Autonomous Underwater Vehicle (AUV) Artemis is craned over the side of Australian Defence Vessel Ocean Shield in the search for missing Malaysia Airlines Flight MH370 in the Southern Indian Ocean in his picture released by the Australian Defence Force on April 20, 2014. LSIS Bradley Darvill / Handout via Reuters