|
 The prediction coincided with the end to the abbreviated first
mission by the Bluefin-21 autonomous underwater vehicle six hours
into what was meant to be a 16-hour operation on Monday after it
exceeded its 4.5 km (14,750 feet) depth limit and was automatically
returned to the surface.
The introduction of the undersea drone marks a new slower paced
phase in the search for Malaysia Airlines MH370 which disappeared on
March 8 and is presumed to have crashed thousands of km (miles) off
course with the loss of all 239 people on board.
Authorities, who soon plan to scale back the air and surface search,
are confident they know the approximate position of wreckage of the
Boeing 777, some 1,550 km (960 miles) northwest of Perth, and are
moving ahead on the basis of four acoustic signals they believe are
from its black box recorders.
But having not heard a "ping" for almost a week and with the
batteries on the locator beacons two weeks past their 30-day
expected life, the slow-moving "autonomous underwater vehicle" was
launched on Monday to try and locate wreckage.
"The AUV takes six times longer to cover the same area as the towed
pinger locator. It is estimated that it will take the AUV anywhere
from six weeks to two months to scan the entire search area," Lt.
J.G. Daniel S. Marciniak, a spokesman for the U.S. Seventh Fleet,
said in a statement.
From its aborted first mission, the Bluefin-21 produced six hours of
data which authorities analyzed to find no objects of interest,
Marciniak added. The drone was expected to embark on its second
search mission late on Tuesday.
The robot, which takes two hours to descend another two to return to
the surface, as well as several hours to download data, will build
up a detailed acoustic image of the area using sophisticated
"sidescan" sonar. It hopes to repeat its success in finding a F-15
fighter jet which crashed off Japan last year.
It is capable of spending up to 16 hours scouring the sea floor. If
it detects possible wreckage, it will be sent back to photograph it
in underwater conditions with extremely low light.
Officials are focusing their acoustic search on an area equivalent
to a medium-sized city — 600 sq km (230 sq miles). But the much
broader search area off the Australian coast covers about 60,000 sq
km, according to the government.
[to top of second column] |
The deep sea area now being searched, the Zenith Plateau, has never
been mapped in detail because it is not in any country's economic
zone.
However the sea floor is likely covered in "foraminiferal ooze", a
sludge formed by microscopic marine organisms, which would show up
any large metallic object clearly, James Cook University marine
geologist Robin Beaman told Reuters.
"A sidescan is very good at detecting the difference in the acoustic
return of a hard object versus a soft, muddy sea floor," he said.
"This is quite a good environment for looking for wreck debris,
albeit deep."
The Bluefin's main challenge was to remain within 50 meters (165
feet) of the seabed to ensure the best quality sidescan detection
without exceeding its 4.5 km depth limit which could risk damaging
it, Beaman said.
Malaysian authorities have still not ruled out mechanical problems
as causing the plane's disappearance, but say evidence suggests it
was deliberately diverted from its scheduled route from Kuala Lumpur
to Beijing.
An aircraft's black box records data from the cockpit and
conversations among flight crew and may provide answers about what
happened to the missing plane.
The search for the missing plane is on track to be the most
difficult and expensive search and recovery operation in aviation
history.
(Additional reporting by Matt Siegel in Sydney;
editing by Michael
Perry and Ron Popeski)
[© 2014 Thomson Reuters. All rights
reserved.] Copyright 2014 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
