Officials in charge of tracing Malaysia Airlines flight MH370 have said they will hold off on sending a robot sub deep below the Indian Ocean surface. Instead, the team will listen for any final clues to narrow the hunt.
It had been expected that the unmanned submersible Bluefin 21, which will map the seabed for signs of wreckage, would be deployed on Tuesday.
However, Australian officials heading the hunt for MH370 announced the vessel would likely remain above the surface for several days. The team hopes the search zone, far off Australia's west coast, could be narrowed by the detection of further "pings" from the possible wreckage.
The first "pinger return" that was detected by the Ocean Shield, which is towing advanced US Navy listening equipment, lasted more than two hours. The vessel turned around and picked up the same sound for a further 13 minutes. The Ocean Shield has been deployed on a gradually converging course with the British HMS Echo, which is also carrying sonic detectors.
Australian Defense Minister David Johnston said it was believed the pingers were still active, and that the search could continue for several days.
While the pingers from the plane normally have a battery life of 30 days, Johnston indicated that - on Day 32 of the search - there was still hope they might be functioning.
Australian Search Coordinator Angus Houston said the advice from the manufacturers of the pingers was that the frequency detected, 33.2 kilohertz, could be that emitted by the device. He confirmed that the device would not be deployed until it was certain there would be no more signals from the wreckage.
"It's a large area for a small submersible that has a very narrow field of search," said Houston, adding that the Bluefin 21 would have to travel close to the ocean floor. "That's why it's very important to get another transmission. We need to continue until there's no chance that the devices are still transmitting."
Apparent change of plan
The information appeared to contradict a statement earlier on Tuesday that Bluefin 21 would be deployed below the surface.
Houston himself has said he imagined "we'd be getting very close to that point," while Australian Deputy Prime Minister Warren Truss said he understood the autonomous vessel would be used today.
The pings have been described as the most promising lead so far in the huge international operation to find out what might have become of the plane. The search has hit several snags, with teams initially searching an area hundreds of kilometers south of the current search area.
MH370 went missing on March 8, when its crew last made radio contact with ground control in Malaysia, prompting numerous theories as to what caused its disappearance. The plane was determined to have flown thousands of miles off route, through a "southern corridor" according to satellite data.
rc/av (AFP, AP, dpa, Reuters)