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Bluefin-21, the US-supplied underwater drone fitted to Ocean Shield.
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The hunt for missing Malaysian Airlines flight MH370 was set to switch to the ocean floor today using a robot submersible after suspected black box signals were detected, one month to the day since the jet vanished.
After describing sonic "pings" picked up by the
naval vessel Ocean Shield as the "most promising lead" so far, the
head of the Australian-led search operation warned that hopes of finding
surface debris were fading.
Retired Air Chief Marshal Angus Houston said that the moment
was nearing to deploy the US-made autonomous underwater vessel Bluefin-21 to
scour for wreckage on the seabed.
"I haven't had the discussion this morning, we'll be
having that discussion a little later on," he told national radio. "I
imagine we'd be getting very close to that point."
The search is now focusing on a 600-kilometre arc of the
southern Indian Ocean, far off the coast of western Australia.
Deputy Prime Minister Warren Truss sounded a note of
optimism.
"Today is another crucial day as we try and reconnect
with the signals that perhaps have been emanating from the black box flight
recorders of MH370," he said.
"The connections two days ago were obviously a time of
great hope that there had been a significant breakthrough."
But he added: "It was disappointing that we were unable
to repeat that experience yesterday."
Ocean Shield is criss-crossing the area to try to home in on
the signals again before launching the five-metre long submersible sonar
device, and Truss indicated the deployment was imminent.
"I understand that we are using the autonomous vehicle
to examine the waters in the areas of interests of today," he said.
The signals are being investigated as the clock ticks past
the 30-day lifespan of the emergency beacons on the two data recorders from the
Malaysia Airlines jet, which vanished on March 8 with 239 people on board en
route from Kuala Lumpur to Beijing.
"As a consequence there is a chance the locator beacon
is about to cease transmission, or has ceased transmission," Houston said.
"I think it's absolutely imperative to find something
else and hopefully when we put the autonomous vehicle down, its capability is
such that it'll be able to find wreckage.
"Unfortunately with the passage of time, oceanic drift
and all the rest of it – particularly as a cyclone went through that area in
the last few days – the chances of finding anything on the surface are
diminishing with time."
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| The US Navy's Bluefin 21 Artemis autonomous underwater vehicle (AUV) being hoisted back on board the Australian navy vessel Ocean Shield. The hunt for missing Malaysia Airlines flight MH370 could soon head to the ocean floor using an autonomous sonar vessel after possible black box signals were detected. – AFP pic, April 8, 2014. |
Houston explained that the 4.5 kilometre depth of the ocean
floor was the absolute operating limit for a Bluefin-21, which is designed for
deep sea surveying and can carry video cameras.
"It can't go deeper than that, so it's quite incredible
how finely balanced all of this is," he said.
"It's a long, painstaking process, particularly when
you start searching the depths of the ocean floor."
When the sonar detects unusual formations on the ocean
floor, it is brought back to the surface to fit cameras before returning to the
seabed.
"You can't have the side sonar and the camera down
there together, it's one or the other," Houston said.
"We will continue sortie after sortie until such time
as we pick up evidence that there's something unusual on the ocean floor. We
would then send down the camera.
"What we're after is wreckage, a debris field as people
would say."
Up to 11 military planes, three civilian planes and 14 ships
were Tuesday set to take part in the unprecedented search 2,268 kilometres
northwest of Perth, the Joint Agency Coordination Centre (JACC) said.
Ocean Shield, which picked up two series of pulses lasting
two hours and 20 minutes and then 13 minutes, are operating at the northern end
of the defined search area. China's Haixun 01 and Britain's HMS Echo will work
the southern end.
Commander William Marks of the US Seventh Fleet has said one
of the signals picked up strengthened for a time, then weakened, indicating
crews were near its source.
"That is encouraging because that is what you would
expect if you are indeed moving toward the black box – that it should get
stronger and as you move away from it, it should get weaker," he told AFP.
– AFP, April 8, 2014.
