An archeologist claims he does not believe that the pings heard, by pinger locators aboard vessels looking for the missing Malaysia Airlines jet MH370, could actually be from the plane's black box, as earlier thought.
William Meacher, who is part of the University of Hong Kong, says there are hundreds of marine animals fitted with detectors as their movements are tracked across the world.
Writing for the Malaysian Insider, he said: "For several decades, pingers with frequencies of 30 or 50kHz have been commonly used to track large, deep ocean animals. Location and other data is transmitted to receivers in the ocean or to satellites whenever the animals surfaces. Acoustic pingers are also widely used as fishing net protectors, to drive away predators that would steal fish."
The towed pinger locator (TPL), used in search vessels scouring through the waters in the southern Indian Ocean, had detected certain 'pings' in different locations in the ocean last month. The pings were thought to be from the missing MH370's black box.
Meacher has argued that the evidence obtained by the TPL suggests that the signals were rather from a tracking device, or a pinger attached to a net that is drifting, and not from MH370's remote locator.
"First and foremost is the signal's frequency of 33.3khz. This is NOT within the manufacturer's specs of 37.5 +/- 1 for the black box pinger," the archeologist pointed out.
Citing a message to him from PH Nargeolt, an oceanographer who was involved in the search for Air France 447 that crashed into the Atlantic, Meacher adds that the frequency detected alone proves that the pings were not from MH370's black box.
He also said that scientists from the Woods Hole Oceanographic Institution used a pinger with the same specification as MH370 in their study of baleen whales. The maximum range of detection was found to be 2.3kms. But the distances between the four supposed 'black box pings" were well beyond, at 9.5, 12.3 and 13.6kms, he notes.
Also, Meacher argues that the first detection lasted for over two hours, and the ship that heard it was moving at two knots, so it covered 9kms while the detection lasted.
"Since it can only pick up a signal at most 3kms away, this long detection suggests a target moving parallel or at an angle to the TPL," he stressed.
Investigators have been almost blindfolded by the lack of a clear picture of what exactly happened to MH370, ever since it went missing in the early hours of March 8, just an hour into its journey from Kuala Lumpur to Beijing, carrying 239 people onboard. The massive search has been conducted based on an arc drawn, after UK satellite firm Inmarsat claimed the missing aircraft had followed a particular flight trajectory, based on the 'pings' it received from the aircraft.