A new acoustic signal was detected in the hunt for Malaysia Airlines Flight MH370 yesterday, further boosting confidence that officials are zeroing in on the missing plane after weeks of searching.

The signal, which could be from the plane’s black box recorders, brings to five the number of “pings” detected in recent days within the search area in the Indian Ocean.

The first four signals were detected by a US Navy “Towed Pinger Locator” (TPL) aboard Australia’s Ocean Shield vessel, while the latest was reported by an aircraft picking up transmissions from a listening device buoy laid near the ship on Wednesday.

“While conducting an acoustic search this afternoon a RAAF AP-3C Orion aircraft has detected a possible signal in the vicinity of the Australian Defence Vessel Ocean Shield,” Angus Houston, head of the Australian agency co-ordinating the search, said in a statement.

The data would require further analysis overnight but it showed the potential of being from a “man-made source”, he said.

The mystery of Malaysia Airlines Flight MH370, which disappeared more than a month ago, has sparked the most expensive search and rescue operation in aviation history, but concrete information has proven frustratingly illusive.

The black boxes record cockpit data and may provide answers about what happened to the plane, which was carrying 227 passengers and 12 crew when it vanished on March 8 and flew thousands of kilometres off its Kuala Lumpur-to-Beijing route.

But the batteries in the black boxes have already reached the end of their 30-day expected life, making efforts to swiftly locate them on the murky ocean floor all the more critical.

Things are more positive than they were some time ago

“We are still a long way to go, but things are more positive than they were some time ago,” Martin Dolan, chief commissioner of the Australian Transport Safety Board, which is involved in the search mission, told Reuters.

Up to 10 military aircraft, four civil aircraft and 13 ships are involved in the search effort that has proven fruitless in identifying any physical evidence of wreckage from the flight. Efforts are now focused on two areas – a larger one for aircraft and ships about 2,240km northwest of Perth and a smaller area about 600km closer to that west Australian city.

The smaller zone is around where the Ocean Shield picked up the acoustic signals and where dozens of acoustic sonobuoys were dropped on Wednesday. Each of the sonobuoys is equipped with a listening device called a hydrophone, which is dangled about 305 metres below the surface and is capable of transmitting data to search for aircraft via radio signals.

“That does provide a lot of sensors in the vicinity of the Ocean Shield without having a ship there to produce the background noise,” said Australian Navy Commodore Peter Leavy, operational head of the Australian search.

But experts say the process of teasing out the signals from the cacophony of background noise in the sea is a slow and exhausting process. Operators must separate a ping lasting just 9.3 milliseconds – a tenth of the blink of a human eye – and repeated every 1.08 seconds.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.