Malaysia Airlines MH370: search area shrinks after more signals detected

Updated

The search area for missing Malaysian Airlines flight MH370 has been narrowed following the detection of two more signals from what is hoped to be the plane's black box.

Australian Defence vessel Ocean Shield has now detected four signals in an area less than 40 kilometres apart, prompting the Indian Ocean search zone to be reduced from 75,000 square kilometres to 57,923.

The centre of the search area lies approximately 2,280 kilometres north west of Perth.

Retired Air Chief Marshal Angus Houston says it may just be a matter of days before they close in on MH370's "final resting place".

"I think we're looking in the right area, but I'm not prepared to confirm anything until such time as somebody lays eyes on the wreckage," he said.

Air Chief Marshal Houston says the Ocean Shield will be looking to pick up more transmissions which would help to better pinpoint where the signal is coming from.

He says once the search area has been narrowed down, searchers could then find something in a "matter of days".

"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," he said.

The reduced search area has also led to a boost in visual search operations on the ocean surface.

Aircraft and ships reported spotting a large number of objects during yesterday's search, but only a small number were able to be recovered.

None of the recovered items were believed to be associated with MH370.

Up to 10 military aircraft, four civil aircraft and 13 ships are involved in today's search.

The Royal Australian Air Force is also dropping sonar buoys into the water to help pick up more signals.

Both signals picked up on Tuesday lasted just over five minutes. However the signals were becoming weaker, which may be due to the batteries running out.

What is the Bluefin-21?

An autonomous underwater vehicle (AUV) designed for deep-sea surveying.

It has a "swappable payload". It will first use sonar in the search and will be refitted with cameras if something is detected.

It's 5m long and weighs 750kg. Has an endurance of 25 hours underwater at a speed of 3 knots, with a top speed of 4 knots.

It has a depth rating of 4,500m, meaning it will be at its limit in the Indian Ocean search zone.

Bluefin Robotics says its AUV can also be used for archaeology, oceanography, mine countermeasures, and unexploded ordnance.

Once the signal dies, an autonomous underwater vehicle called the Bluefin-21 will be deployed to scan the ocean floor, which is more than four kilometres deep.

Air Chief Marshal Houston says an underwater search could present its own challenges.

"I'm informed by experts that there's a lot of silt down there," he said.

"That could complicate the search because the silt on the bottom of the ocean can be very thick and things disappear into it and it makes a visual search underwater very difficult."

He says an underwater search can take up to six times longer to cover the same area as a search on the surface.

Signals cannot be used to officially verify the missing plane, and Air Chief Marshal Houston says he wants more.

"I'd just like to have that hard evidence - a photograph - that there are pieces of evidence down there," he said.

Once located, a new type of submersible will be needed to bring the wreckage to the surface, and hopefully find the crucial flight data and voice recorders.

Meanwhile, preparations are underway in Perth to accommodate the families of those missing on the flight.

MH370 went missing on March 8 with 239 people on board, including six Australians. The majority of those on board were Chinese.

Topics: air-and-space, disasters-and-accidents, perth-6000, wa, australia, malaysia

First posted