HMAS Albatross is playing a critical role in attempting to find the missing Malaysia Airlines flight MH370.
Personnel at the Australasian Joint Acoustic Analysis Centre at HMAS Albatross are analysing pings received from the search zone, possibly from the flight data recorder on the missing plane.
Staff at the high security establishment analysed the first two pings - detected on April 5 at 4.45pm and at 9.27pm Perth time.
That analysis determined that a very stable, distinct and clear signal was detected at 33.331 kilohertz that consistently pulsed at a 1.106-second interval.
The head of the search's Joint Agency Co-ordination Centre Retired Air Chief Marshal Angus Houston said it was a “promising development”, reviving hope the missing Malaysia Airlines plane's black box is still transmitting data days after its batteries were due to run dead.
Mr Houston said the transmission had been assessed and was not of natural origin, and was likely sourced from specific electronic equipment.
“The signals are believed to be consistent with the specification and description of a flight data recorder,” he said.
He said the two latest pings were detected on Tuesday - at 4.27pm and 10.17pm, Perth time.
The Australian Defence Vessel Ocean Shield, towing a US pinger locator, detected two sets of pings on Tuesday afternoon and then again about five hours later.
The signal detected on Tuesday afternoon was held for about five minutes and 32 seconds; followed by a second signal on Tuesday night, which was held for seven minutes.
The development came more than two days after Ocean Shield first detected the month-long search's most promising lead: two acoustic events on Saturday.
Eleven military aircraft including an S-70B2 Seahawk helicopter and its 16-member flight crew from 816 Squadron at HMAS Albatross are taking part in the search efforts from on board the Anzac frigate HMAS Toowoomba, along with four civil aircraft and up to 14 ships.
The search area has been refined to a single zone, about 75,423 square kilometres in size, 2261 kilometres north west of Perth, which was a considerably smaller area than in previous days.
“It looks like the signals we picked up recently have been much weaker than the original signals we picked up ... we're either a long away from it or in my view more likely the batteries are starting to fade,” Mr Houston said.
A RAAF aircraft has been diverted to Ocean Shield to drop buoys around the field to lay a “sonar buoy pattern”, which will involve underwater and floating components transmitting data back to the aircraft.
That will provide a range of sensors, 1000 feet down, which is 1000 feet closer to the pinger locator on the ocean floor.
Despite an extensive and costly international search operation off the West Australian coast, the effort has failed to turn up a single piece of evidence to confirm the plane's final resting place.