SYDNEY — Almost six months after Malaysia Airlines Flight 370 disappeared with 239 people on board, officials expressed cautious optimism Thursday that the jet would eventually be found, as Australia, China and Malaysia concluded agreements on continuing the search in the southern Indian Ocean for 12 more months.
“All of the countries involved remain cautiously optimistic that we will find the missing aircraft,’’ Australia’s deputy prime minister, Warren Truss, said at a news conference in Canberra, the Australian capital, with Malaysia’s transport minister, Liow Tiong Lai, and China’s vice minister for transport, He Jianzhong.
Truss said teams continued to refine the search area, noting that data from a failed attempt to contact the plane with a satellite phone had provided some new information.
“After MH370 disappeared from the radar, Malaysia Airlines ground staff sought to make contact with the aircraft using a satellite phone,’’ Truss said. “That was unsuccessful. But the detailed research that is being done now has been able to identify or trace that phone call and help to position the aircraft and the direction it was traveling. That has suggested to us that the aircraft may have turned south a little earlier than we had previously expected.’’
Flight 370 left Kuala Lumpur, Malaysia, on March 8 on an overnight flight to Beijing, but it inexplicably turned off course and headed south. Transmissions from the aircraft, known as electronic “handshakes,’’ captured by a satellite station in Perth indicated that the flight had come to an end off the west coast of Australia, somewhere on a long arc over the Indian Ocean.
But a 52-day air search of the sea surface off Australia’s coast, as well as the use of towed undersea devices able to track “pings’’ from an aircraft’s so-called black boxes, failed to turn up a single trace of the Boeing 777-200. Officials believe the plane flew south for hours on autopilot, but they do not know why its communications systems were switched off or why it deviated from its flight path.
Truss said no conclusions could be reached about what had happened in the plane’s cockpit until the black boxes were retrieved.
The search area remains on the arc determined by the last electronic handshake picked up from the plane, but Truss said the area had been refined slightly in light of the data gleaned from the failed satellite phone call.
Truss also described the area of ocean floor where the Australian Transport Safety Bureau will lead a deep-sea search starting in September. In some places it is more than 4 miles deep, he said, and it is studded with volcanoes and plateaus that could damage surveying equipment.
A bathymetric survey, or mapping of the seafloor, in the search area has covered more than 33,000 square miles and revealed at least two volcanoes, as well as significantly greater depths than had been expected, Truss said.
Truss and Liow said the cost of the search during the next 12 months, unless the plane is found sooner, would probably be in the order of $49 million, to be divided equally between Malaysia and Australia. China is to provide search vessels and make other contributions. Most of Flight 370’s passengers were Chinese.
Liow said he hoped to be able to provide families of the missing with more timely and regular updates on the progress of the search.