Searchers engaged in a race against time to pinpoint "pings" from the missing Malaysian airliner's black boxes yesterday detected a possible fifth signal, fuelling hopes that wreckage will soon be found.
The beacons on flight MH370's data and cockpit voice recorders are due to fade, more than a month after the Boeing 777 vanished. So the Australian-led search is vying to determine an exact location before sending down a submersible to plumb the Indian Ocean depths.
The Perth-based Joint Agency Coordination Centre (JACC) said the latest ping was detected yesterday afternoon by an Australian air force P-3C Orion surveillance plane, which has been dropping dozens of sonar buoys into the remote waters of the search zone.
"The acoustic data will require further analysis overnight but shows potential of being from a made-made source," JACC chief Angus Houston said in a statement.
The Australian ship Ocean Shield, bearing a special US Navy "towed pinger locator", is now focused on a far smaller area of the Indian Ocean 2,280 kilometres (1,400 miles) northwest of Perth where it picked up two fresh signals Tuesday.
Those transmissions matched a pair of signals logged over the weekend.
"When you put those two (sets of pings) together, it makes us very optimistic," US Seventh fleet spokesman commander William Marks said earlier on CNN, adding that the search was getting "closer and closer".
Marks said he expected the pings to last "maybe another day or two" as the batteries powering the black box beacons fade after their normal lifespan of about 30 days.