MH370 search: Hunt for plane narrows to Indian Ocean strip

The search for the missing Malaysia Airlines Flight MH370 has narrowed to a strip of the Indian Ocean but faces numerous challenges as it seeks to locate the aircraft's black box in a stretch of deep and little-known water. A search aircraft detected a further signal believed to be from the black-box locator beacon yesterday, following the previous day's dramatic announcement that two sets of signals were heard on Tuesday. The signal was picked up by an Australian P-3 Orion surveillance aircraft which was conducting an acoustic search. "The acoustic data will require further analysis overnight but shows potential of being from a man-made source," said search coordinator Angus Houston. Following the detections on Tuesday and two sets of signals heard last Saturday, Houston, the former Australian defence chief who heads the Joint Agency Coordination Centre, predicted the aircraft was likely to be found "in a matter of days". But he noted yesterday that he was not confident about the black-box beacon continuing to ping for much longer "because the likelihood on Day 34 is that the batteries must be getting near their use-by date". An Australian navy vessel, Ocean Shield, is towing a black-box pinger locator to try to detect further signals before the pinger's batteries run out. The batteries last about 30 days - and the plane, carrying 239 people, disappeared 35 days ago today. The underwater search is focused on a little-charted part of the Indian Ocean bordering two areas known as the Wharton Basin and the Perth Abyssal Plain. The coordination centre confirmed to The Straits Times yesterday the search area had been narrowed to a strip that was "30km in length by 20km in width". The difficulties of locating and retrieving the black box were laid out on Wednesday by Commodore Peter Leavy, the operational head of the Australian search, who said "we know more about the surface of the moon than our own seabed of our ocean floor". "The indication we have that silt is on the seabed is taken from some core samples that were taken some years ago and 130 miles (209km) away… That gives an indication of how little understanding we have of the detailed topography of the seabed," he said. Experts said challenges are great because the waters are deep and the ocean floor is complex. Professor Neville Exon, a marine scientist at the Australian National University, said the area was mostly flat and the main obstacle was the area's water depth. A trough in the region reaches depths of more than 5,000m but the flatter part of the search area is about 4,500m deep. "It is in quite a complicated area. A mixture of soft sediment and rocky ridges is likely to be common in the general area of the pinger location... The water depth makes it incredibly difficult." The authorities are seeking to further refine the search area and will stop using the pinger locator only once they deem the signals have ended or if they find the precise location of the black box. An unmanned submarine will then be deployed to capture an image of the ocean floor but it operates to a depth of only about 4,500m. The search yesterday included 10 military and four civil aircraft and 13 ships covering an area of 57,923 sq km. A Chinese and a British vessel with underwater capabilities were seeking signals in an area south of where the Ocean Shield was operating.