When the ping locator’s use is exhausted, the unmanned sub will be sent to create a sonar map of a potential debris field on the seabed. The Bluefin 21 sub takes six times longer to cover the same area as the ping locator.
Matthews said the detections indicate the beacon is within about a 20-kilometer (12-mile) radius, equal to a 1,300-square-kilometer (500-square-mile) chunk of the ocean floor.
That’s like trying to find a desktop computer in a city the size of Los Angeles and would take the sub about six weeks to two months to canvass. So it makes more sense to continue using the ping locator to zero in on a more precise location, Matthews said.
The Bluefin sub’s sonar scans about to 100 meters and can “see” with lights and cameras only a few meters. Its maximum dive depth is 4,500 meters, and some areas of the search zone are deeper.
The audio search was narrowed to its current position after engineers predicted a flight path by analyzing signals between the plane and a satellite and investigators used radar data to determine the plane’s speed and where it may have run out of fuel.
Houston noted that all four of the pings detected since Saturday were near the site of a final, partial “handshake” signal revealed earlier in the investigation.
He also noted the surface search for any floating debris has been adjusted and intensified based on where the four pings were heard and where ocean currents might have caused objects to drift. Fifteen planes and 14 ships searched a 75,400-square-kilometer area that extends from 2,250 kilometers northwest of Perth on Wednesday.
Despite the challenges, those involved in the hunt were buoyed by the Ocean Shield’s findings.
“I’m an engineer so I don’t talk emotions too much,” Matthews said. “But certainly when I received word that they had another detection, you feel elated. You’re hopeful that you can locate the final resting place of the aircraft and bring closure to all the families involved.”