Search crews looking for missing Malaysia Airlines Flight 370 this weekend have detected several "pings" on underwater sonar equipment that they said were "consistent with those emitted from airplane black boxes," retired Australia Air Chief Marshal Angus Houston said.
The signals could be a major break in the search for the plane that disappeared March 8 during a flight from Malaysia to China with 239 passengers on board. Here are the next steps in the international search operation:
Battery Life Expiring
The battery life on a plane's black box is set to last about 35 days after a plane disappears, which means that it should be getting close to running out since the plane disappeared 31 days ago. The maker of the black box, U.S. company Dukane Seacom, told the BBC that the battery should have "three to four more days of good, solid output."
Search teams will be focusing their efforts on finding additional pings in the next 72 hours before the signal begins to fade.
Deep Dive Exploration
The pings were heard in the deepest parts of the Indian Ocean, about 2.8 miles or 14,000-plus feet below the surface, so crews will deploy deep water search vehicles and submarines to try and find more pings.
"In very deep oceanic water, nothing happens fast," Houston said.
"We need to reacquire this same signal. Once we get that we can get a good location of where we think these black boxes are. And then we can deploy our side scan sonar," Commander William Marks, a spokesman for the U.S. Navy's Seventh fleet, told ABC News today.
High-Tech Underwater Drones
The Navy has sent an autonomous underwater vehicle, basically a deep-sea drone, to the search site to help look for signs of the plane. The Bluefin 21 can dive as deep as 14,000 feet. It's limit is right about the depth of the Indian Ocean where the pings were detected. They will use the Bluefin and British submarines to try and confirm the pings in the next few days.
Once Pings Are Confirmed, Search for Wreckage Begins
Even if the pings are confirmed and search crews can pinpoint where the plane went down, it could still take a long time to find the wreckage and recover the black boxes, as searchers who worked on the Air France Flight 4476 recovery learned in 2009. The vehicles that recovery teams use can search about 25 square miles a day, he said.
"The Air France plane crashed far from shore in an area with fairly deep water and a very rugged sea floor," said Mike Purcell, principal engineer for the Woods Hole Oceanographic Institution who worked on the recovery of the Air France wreckage.
"A search area location far from shore requires good planning," Purcell said in an email to ABC News. "Initially, our underwater vehicles had some problems with the rugged terrain, but with some modifications we adapted to the terrain. There were concerns that the wreckage would lie in an area of very rugged terrain and be difficult to spot with our acoustic sensors."