A thick layer of silt in the area where searchers are hunting for missing Flight 370 could dampen or distort signals emitted by the plane’s black box and hide wreckage lying on the ocean floor, investigators said on Wednesday.
"It could be sinking into silt, it could be the batteries are reaching the end of their life," U.S. Navy Capt. Mark Matthews, who is advising the searchers, told reporters.
Officials have warned that batteries in the pingers are likely reaching the end of their 30-day expected life.
Silt could also hide wreckage and distort the sounds emanating from a black box, Royal Australian Navy Commodore Peter Leavy said on Tuesday. Leavy is helping lead the search.
Matthews was hopeful that searchers had zeroed in on Flight 370's location, saying it was “certainly a man-made device emitting that signal” and he had no explanation for what else it could be.
The recent pings heard by an Australian search vessel towing a U.S. Navy owned pinger locator indicate the device emitting them is within around a 12-mile radius, he said. That equates to a 500-square-mile area of the ocean floor, he added.
It would take an unmanned submarine six times longer to cover the area than the pinger locator being pulled behind a ship at a depth of almost 10,000 feet, Matthews added.
The Associated Press contributed to this report.