Bruce Dorminey, Contributor
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4/09/2014 @ 3:42AM |46,297 views
In a major break in a race against time, searchers for MH370 have detected two new electronic pings — both received in the last 24 hours — from what they hope is the missing Boeing 777-200’s black box flight data recorders. The news was announced at a Wednesday morning press conference in Perth.
“I’m now optimistic that we will find the aircraft; what’s left of the aircraft,” Retired RAAF Air Marshal Angus Houston told reporters.
Just days before batteries on the black box pingers are expected to expire, Australian authorities leading the southern Indian Ocean search for the Malaysia Airlines 777 confirmed that Australian Defence Vessel Ocean Shield had, in fact, detected two new pings in the current northernmost search area; or some 1500 km (930 mi) northwest of Perth.
The U.S. Navy’s TPL-25 Towed Pinger Locator sonar, now deployed on the Ocean Shield, has been operating 24 hours a day at depths of up to 9000 ft. Thus far, it has detected four separate ping events; two on April 5th and two on April 8th local time.
The U.S. Navy assists in the search for Malaysia Airlines flight MH370. (Photo credit: Official U.S. Navy Imagery)
The most recent signals detected by the ocean shield were consistent with what you would expect from a black box held for a little more than five minutes, Seventh Fleet spokesman Cmdr. William Marks told Forbes.com.
“It’s a continuous pinging, with pings at one-second intervals,” Marks said by phone from aboard the U.S.S. Blue Ridge. “Our sonar can pick it, but it’s not audible to the human ear.”
Marks says the pingers attached to the two separate black boxes — a cockpit voice recorder and a separate flight data recorder — each give out separate continuous signals until they run out of battery life, which by some estimates could be any day now.
“The batteries just fade, like a flashlight getting dimmer and dimmer,” said Marks.
The Ocean Shield search track is in what marks has described as a “ladder pattern” not unlike a pattern used to mow a lawn; following a straight course in one direction which is then reversed on a slightly different heading.
The key to it all is in triangulating the black box locations by using individual lines of bearing. Thus far, the Ocean Shield crew has detected four lines of bearing. But ideally, they would need a few more in order to hone the black boxes’ positions to optimally only a few couple of hundred yards.
The key to it all is in triangulating the black box locations by using individual lines of bearing. Thus far, the Ocean Shield crew has detected four lines of bearing. But ideally, they would need a few more in order to hone the black boxes’ positions to optimally only a few couple of hundred yards.
The goal, says Marks, is to triangulate the signals using various lines of bearing (or direction). To do that, he said the Ocean Shield needs to have a wide range of motion to detect the signal at various points along the search track.
“When we had two hours of coverage on the 5th,” said Marks, “the signal got stronger and stronger and then weaker and weaker. That’s consistent with how it should be if you are getting closer to the black boxes or further away.”
A U.S. official who requested anonymity told Forbes.com that the signals detected by the Ocean Shield do not occur in nature and could not be caused by a commercial shipping vessel.
However, Marks said it’s too soon to say that they have differentiated between the two separate signals since they both ping at about the same frequency of 37.5 kHz.
“We have the [search area] narrowed down to a small defined boundary within tens of km,” said Marks. “That’s pretty darned defined considering the vastness of the Indian Ocean.”
Source: http://www.forbes.com
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