A family member of another passenger said staying together allowed the relatives to support one another through the ordeal. “If we go back to our homes now, it will be extremely painful,” said Steve Wang. “We have to face a bigger pain of facing uncertainty, the unknown future. This is the most difficult to cope with.”
Investigators have not found any explanation yet for why the plane lost communications and veered far off its Beijing-bound course, so the black boxes containing the flight data and cockpit voice recorders are key to learning what went wrong.
“Everyone’s anxious about the life of the batteries on the black box flight recorders,” said Truss, who is acting prime minister while Tony Abbott is overseas. “Sometimes, they go on for many, many weeks longer than they’re mandated to operate for — we hope that’ll be the case in this instance. But clearly there is an aura of urgency about the investigation.”
The first sound picked up by the equipment on board the Ocean Shield lasted two hours and 20 minutes before it was lost, Houston said. The ship then turned around and picked up a signal again — this time recording two distinct “pinger returns” that lasted 13 minutes. That would be consistent with transmissions from both the flight data recorder and the cockpit voice recorder.
The black boxes normally emit a frequency of 37.5 kilohertz, and the signals picked up by the Ocean Shield were both 33.3 kilohertz, U.S. Navy Capt. Mark Matthews said.
Houston said the frequency heard was considered “quite credible” by the manufacturer, and noted that the frequency from the Air France jet that crashed several years ago was 34 kilohertz. The age of the batteries and the water pressure in the deep ocean can affect the transmission level, he said.
The Ocean Shield is dragging a pinger locator at a depth of 1.9 miles. It is designed to detect signals at a range of 1.12 miles, meaning it would need to be almost on top of the recorders to detect them if they were on the ocean floor, which is about 2.8 miles deep.
The surface search for any plane debris also continued Tuesday. Up to 14 planes and as many ships were focusing on a single search area covering 29,954 square miles of ocean, said the Joint Agency Coordination Center, which is overseeing the operation.