The
signal had a frequency of 37.5 kHz, the report said, which is the
frequency used for all standard underwater locator devices attached to
aircraft data and voice recorders, commonly known as black boxes.
Hours
after the report, the Australian chief coordinator of the Indian Ocean
search, retired Air Chief Marshall Angus Houston, said “the
characteristics reported are consistent with the aircraft black box.” He
also noted that white objects had been spotted floating in the water
about 56 miles from the area where the sounds were heard.
But
he urged caution, saying the reports could not be immediately verified
-- a sentiment echoed by Malaysian and Chinese officials.
“There
is no confirmation at this stage that the signals and the objects are
related to the missing aircraft,” said Mr. Houston, chief of the Joint
Agency Coordination Center, an Australian government group.
False
alerts can be triggered by sea life, including whales, or by noise from
ships. An alert sounded on the British Royal Navy vessel HMS Echo last
week turned out to be false, according to the Australians.
The
Chinese vessel, Haixun 01, was searching about 1,020 miles northwest of
Perth, Australia, on Saturday when it picked up the pulse signal,
Xinhua reported.
In
the four weeks since Flight 370 veered off its scheduled path from
Kuala Lumpur to Beijing and dropped off civilian and military radar, no
trace of the plane has been found. In the past week, searchers have
concentrated their efforts in several areas of the Indian Ocean more
than 900 miles off the coast of Perth, Australia. A flotilla of ships
from various nations have combed the water as aircraft have conducted
daily reconnaissance flights.
Crews
aboard the planes and ships have spotted floating items nearly every
day, but so far all the objects have turned out to be fishing equipment
and other detritus not related to Flight 370.
On
Saturday, 10 military planes, 3 civilian jets and 11 ships were
scheduled to search an area about 1,050 miles northwest of Perth, and
the signal reported by the Chinese ship appeared to come from that area,
according to coordinates provided by Xinhua.
The
Haixun 01 has been a regular member of the search flotilla for days and
is one of at least eight vessels China has deployed to the Indian Ocean
to help in the search.
On
Friday, search coordinators announced that the underwater phase of the
hunt had begun with the addition of two military ships — one from
Australia and the other from Britain — equipped with underwater sensor
technology.
Both
those ships planned to resume their underwater search on Saturday, the
Australian Coordination Center said in a statement early in the day.
There was no mention, however, of the Haixun 01’s part in the underwater
search or whether it was outfitted with technology for detecting black
boxes.
The
Haixun 01 went into service last year, when the Shanghai Maritime
Safety Administration said it was the biggest of China’s civilian
maritime administration vessels with the most advanced equipment.
Black
boxes are equipped to emit a signal that can be detected by a receiver
under the surface of the water. The maximum detection range is typically
up to about two to three kilometers, or less than two miles, though the
range is dependent on various factors including the sensitivity of the
receiver, sea conditions, water temperature or whether the black boxes
are buried by debris.
Much
hope is riding on the effectiveness of the underwater listening
devices. The black boxes’ batteries, which have a life span of about a
month, are expected to expire as early as this week. When they die, so
will the pinger signal, leaving the boxes to rest mutely on the seabed,
making their discovery far more difficult.
Source: NYTimes
