The signals detected 1,020 miles northwest of Perth by the Ocean Shield’s towed ping locators are the strongest indication yet that the plane crashed and is now at the bottom of the ocean in the area where the search is now focused.
A data analysis of the signals heard Saturday determined they were distinct, man-made and pulsed consistently, Houston said.
“They believe the signals to be consistent with the specification and description of a flight data recorder,” he said.
To assist the Ocean Shield, the Australian navy dropped buoys by parachute in a pattern near where the signals were last heard.
Royal Australian Navy Commodore Peter Leavy said each buoy will dangle a hydrophone listening device about 1,000 feet below the surface. The hope, he said, is the buoys will help better pinpoint the signals.
Houston acknowledged that searchers were running out of time, noting the last two signals were weaker and briefer than the first pair heard Saturday, suggesting the batteries are failing. One lasted two hours and 20 minutes and the second lasted 13 minutes; those heard Tuesday lasted just 51/2 minutes and 7 minutes.
“So we need to, as we say in Australia, ‘make hay while the sun shines,’” Houston said.
The weakening of the signals also could indicate the device was farther away, U.S. Navy Capt. Mark Matthews said. Temperature, water pressure or the saltiness of the sea could also be factors.
Leavy said thick silt on the ocean floor also could distort the sounds and may hide wreckage from the eventual visual search.
Houston said a decision had not yet been made on how long to use the towed ping locator while knowing the beacons’ batteries will likely fail soon, saying only that a decision to deploy an unmanned submarine in the search was “not far away.”
“Hopefully in a matter of days, we will be able to find something on the bottom that might confirm that this is the last resting place of MH370,” he said.