No new signals detected as search narrows in on black box

The search for missing Malaysia Airlines flight MH370 continues today with authorities confirming no further acoustic signals have been detected in the past 24 hours.  [Special coverage]

Prime Minister Tony Abbott on Friday said authorities were "very confident" that a series of signals picked up in the Indian Ocean were from the plane's black box.

But while he said the search area had been significantly narrowed to within "some kilometres", he warned the signals were starting to fade.

The search for the flight recorders is focused on an area, 1,670 kilometres north-west of Perth, where dozens of acoustic sonobuoys were dropped on Wednesday.

Today's search involves up to 10 planes and 14 ships and the Ocean Shield will continue scouring the area with its underwater pinger locator.

The so-called black box, which refers to two orange boxes that record flight data and cockpit chatter, may provide answers about what happened to the plane, which was carrying 227 passengers and 12 crew when it vanished on March 8.

It was flying thousands of kilometres off its Kuala Lumpur to Beijing route.

The quick recovery of the flight recorders is critical as the batteries in the boxes have already reached the end of their 30-day expected life, meaning the underwater pulse they send out may fade or cease.

Mr Abbott said yesterday that although the search area had narrowed there were still significant challenges.

"We are confident that we know the position of the black box flight recorder to within some kilometres, but confidence in the approximate position of the black box is not the same as recovering wreckage from almost four-and-a-half kilometres beneath the sea," he said.

Once the final search area has been identified an autonomous underwater vehicle, the Bluefin-21, could be deployed to look for wreckage on the sea floor.

In a statement released after Mr Abbott spoke yesterday, search coordinator retired Air Chief Marshal Angus Houston said there had been "no major breakthrough".

"On the information I have available to me, there has been no major breakthrough in the search for MH370," he said.

"I will provide a further update if, and when, further information becomes available."

The Australian Maritime Safety Authority (AMSA) said yesterday's search efforts also took place in two other areas hundreds of kilometres further west of the black box's believed location.

The Joint Agency Coordination Centre (JACC), based in Perth, confirmed yesterday that a signal detected by a RAAF P3 Orion on Thursday night was not related to the underwater aircraft beacon.