9 Apr 2014

Two more ‘pings’ heard in hunt for MH370

Australian officials have detected two new signals in the hunt for missing Malaysia Airlines flight MH370 but time is running out as the batteries in on flight black boxes are expected to fail soon.

The Australian search ship ‘Ocean Shield’ detected one “ping” on Tuesday afternoon that last for five minutes and 25 seconds, and a second “ping” on Tuesday night which was maintained for seven minutes.

Over the weekend, two other signals in the “same broad area”, were detected.

Angus Houston, head of the Australian agency coordinating the search, said the new “pings” would help create a “much more manageable search area on the ocean floor.”

“I believe we are searching in the right area but we need to visually identify aircraft wreckage before we can confirm with certainty that this is the final resting place of MH370.”

Read more: Would finding the black box help solve MH370 mystery?

The battery powered black boxes have already reached the end of their 30-day life expectancy, meaning the search teams are now operating on “bonus time”.

The search for MH370, which disappeared on 8 March with 239 people on board, is now centred on an area around 1,400 miles northwest of Perth in Australia. The search area total more than 29,000 square miles.

Shrinking search area

Two more detections of faint electronic pings from deep in the ocean doesn't sound like a lot, but they could be the difference between finding the wreckage of the missing jet or not, writes Science Editor Tom Clarke

The "towed pinger locator" being dragged behind the Australian search ship is able to establish the direction of where the pings are coming from. Having two more detections means there can now start to triangulate the position of the flight data recorder.

Detailed analysis of the pings heard at the weekend has also confirmed they are from "specific electronic equipment" -- most likely a flight data recorder.

Angus Houston who is heading up the search concluded last night: "I'm now optimistic that we will find the aircraft, or what is left of the aircraft in the not too distant future."

That's because all the locations from which they have heard pings are within 20 kilometres of each other - a radically smaller search area than the one they were dealing with just a few days ago.

Furthermore, now they have four different points from which they can draw virtual lines from in the direction from which the sound was coming. The triangulation - where those lines overlap - will then further narrow the search area.

But there are still challenges to pinpointing the wreckage. "The main problem is sound waves don't travel in straight lines underwater," said Prof David Stupples an electronic engineer at City University of London. Signals can bounce off terrain and even be deflected by layers of seawater at different temperatures.

Once the search teams believe the batteries on the black boxes have run out, a submarine will be sent underwater to search for the plane’s wreckage. The water in the area is more than two miles deep.

Mr Houston told reporters in Perth: “Now hopefully with lots of transmissions we’ll have a tight, small area and hopefully in a matter of days we will be able to find something on the bottom that might confirm that this is the last resting place of MH370.”

Read more from Science Editor Tom Clarke: MH370 search faces ridges, canyons and spiralling costs

“Bear in mind, that the time spent on the surface, we’re covering six times more area and any given time than we’ll be able to do when we go underwater. So with the batteries likely to fade or fail very shortly, we need to get as much positional data as we can so that we can define a very small search area.”