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| The chief coordinator of the Joint Agency Coordination Center retired Chief Air Marshall Angus Houston shows a map to the media during a press conference about the on going search operations for wreckage and debris of missing Malaysia Airlines Flight 370 in Perth, Australia, Monday, April 7, 2014. Houston reported the towed pinger locator deployed from the Ocean Shield has detected two signals consistent with those emitted by an in flight back box recorder, in the northern part of the current search area in the southern Indian Ocean. |
PERTH, Australia
(AP) -- After a month of failed hunting and finding debris that
turned out to be ordinary flotsam, an Australian ship detected faint
pings deep in the Indian Ocean in what an official called the "most
promising lead" yet in the search for Flight 370.
Officials
coordinating the multinational search for the missing Malaysia Airlines
jet still urged caution Monday after a weekend that also brought
reports of "acoustic noise" picked up by a Chinese vessel also trying to
solve the aviation mystery.
The Boeing 777 vanished March 8 while flying from Kuala Lumpur, Malaysia, to Beijing with 239 people on board.
The
focus of the search changed repeatedly since contact was lost with the
plane between Malaysia and Vietnam. It began in the South China Sea,
then shifted toward the Strait of Malacca to the west, where Malaysian
officials eventually confirmed that military radar had detected the
plane.
An analysis of satellite data indicated
the plane veered far off course for a still-unknown reason, heading to
the southern Indian Ocean, where officials say it went down at sea. They
later shifted the search area closer to the west coast of Australia.
"We
are cautiously hopeful that there will be a positive development in the
next few days, if not hours," Malaysian Defense Minister Hishammuddin
Hussein said in the capital of Kuala Lumpur.
But
Angus Houston, the retired Australian air chief marshal who heads the
search operation, added: "We haven't found the aircraft yet."
The
Ocean Shield, an Australian ship towing sophisticated U.S. Navy
listening equipment, detected two distinct, long-lasting sounds
underwater that are consistent with the pings from an aircraft's "black
boxes" - the flight data and cockpit voice recorders, Houston said.
Navy
specialists were urgently trying to pick up the signal detected Sunday
by the Ocean Shield so they can triangulate its position and go to the
next step of sending an unmanned miniature submarine into the depths to
look for any plane wreckage.
Geoff Dell,
discipline leader of accident investigation at Central Queensland
University in Australia, said it would be "coincidental in the extreme"
for the sounds to have come from anything other than an aircraft's
flight recorder.
"If they have a got a
legitimate signal, and it's not from one of the other vessels or
something, you would have to say they are within a bull's roar," he
said. "There's still a chance that it's a spurious signal that's coming
from somewhere else and they are chasing a ghost, but it certainly is
encouraging that they've found something to suggest they are in the
right spot."
And in "very deep oceanic water," Houston said, "nothing happens fast."
"Clearly,
this is a most promising lead," he said in Perth. "And probably in the
search so far, it's probably the best information that we have had."
Houston
said the signals picked up by the Ocean Shield were stronger and lasted
longer than faint signals a Chinese ship reported hearing about 555
kilometers (345 miles) south in the remote search zone off Australia's
west coast.
The British ship HMS Echo was
using sophisticated sound-locating equipment to determine whether two
separate sounds heard by the Chinese patrol vessel Haixun 01 were
related to Flight 370. The Haixun detected a brief "pulse signal" on
Friday and a second signal Saturday.
The
Chinese reportedly were using a sonar device called a hydrophone dangled
over the side of a small boat - something experts said was technically
possible but extremely unlikely. The equipment aboard the British and
Australian ships is dragged slowly behind each vessel over long
distances and is considered far more sophisticated.
Little
time is left to locate the flight recorders, whose locator beacons have
a battery life of about a month.
Tuesday marks exactly one month since
the Malaysia Airlines plane disappeared.
China's
official Xinhua News Agency reported late Saturday that the signal
detected by the Haixun crew was pulsing at 37.5 kilohertz - the same
frequency emitted by flight data recorders. Malaysia's civil aviation
chief, Azharuddin Abdul Rahman, confirmed the frequency emitted by
Flight 370's black boxes was 37.5 kilohertz.
The Ocean Shield picked up its signals late Saturday night and early Sunday morning.
The
first lasted two hours and 20 minutes before it was lost. The ship then
turned around and picked up a signal again - this time recording two
distinct "pinger returns" that lasted 13 minutes, Houston said.
"Significantly,
this would be consistent with transmissions from both the flight data
recorder and the cockpit voice recorder," Houston said.
The
frequency used by aircraft flight recorders was chosen because no other
devices use it, and because nothing in the natural world mimics it,
said William Waldock, a search-and-rescue expert who teaches accident
investigation at Embry-Riddle Aeronautical University in Prescott, Ariz.
"They picked that so there wouldn't be false alarms from other things in the ocean," he said.
But
these signals are being detected by computer sweeps, and "not so much a
guy with headphones on listening to pings," said U.S. Navy spokesman
Chris Johnson. So until the signals are fully analyzed, it's too early
to say what they are, he said.
"We'll hear
lots of signals at different frequencies," he said. "Marine mammals. Our
own ship systems. Scientific equipment, fishing equipment, things like
that. And then of course there are lots of ships operating in the area
that are all radiating certain signals into the ocean."-
The
Ocean Shield is dragging a ping locator at a depth of 3 kilometers (1.9
miles). It is designed to detect signals at a range of 1.8 kilometers
(1.12 miles), meaning it would need to be almost on top of the recorders
to detect them if they were on the ocean floor, which is about 4.5
kilometers (2.8 miles) deep.
"It's like
playing hot and cold when you're searching for something and someone's
telling you you're getting warmer and warmer and warmer," U.S. Navy
Capt. Mark Matthews said. "When you're right on top of it, you get a
good return."
While Matthews said the signals
picked up by the Ocean Shield were both 33.3 kilohertz, the manufacturer
indicated the frequency can drift in older equipment.
If
they pick up the signal again, the crew will launch an underwater
vehicle to investigate, Matthews said. The Bluefin 21 autonomous sub can
create a sonar map of the area to chart any debris on the sea floor. If
it maps out a debris field, the crew will replace the sonar system with
a camera unit to photograph any wreckage.
The water depth there is right at the limits of the sub's capability.
Meanwhile, the search effort continued on the surface.
Twelve
planes and 14 ships scoured three designated zones, one of which
overlaps with the Ocean Shield's underwater search. All of the previous
surface searches have found only fishing equipment or other sea trash,
something that gave Houston pause.
"I would
want more confirmation before we say this is it," he said. "Without
wreckage, we can't say it's definitely here. We've got to go down and
have a look."
