Black Box From Malaysia Airlines Flight 370 Has Probably Expired, So Search Crews Have A Plan B

After six days of no pings, search crews hunting for the missing Malaysia Airlines jet have decided to give up on detecting signals from Flight 370's black box, and will now be deploying an underwater vessel to scour the southern Indian Ocean instead. The robotic submersible will be sent out Monday night local time, and will create a map of the ocean floor in a process that will take a painfully long time — maybe even months.

With a battery life of only 30 days, the cockpit voice recorder has been the team's main lead in locating the Boeing 777, and hopes were high last week after teams picked up pinger signals consistent with the flight's black box. After nearly a week of silence, though, the crew is now ready to admit that the batteries may have finally died. "We haven't had a single detection in six days, and I guess it's time to go under water," said Angus Houston, who is leading the search and recovery effort, at a press conference.

Late Monday, a small submarine (or "autonomous underwater vehicle") named Bluefin-21 will be sent out to map the floor of the southern Indian Ocean using sonar technology. It's a long, arduous process: the machine will take two hours just to get down to its limit of 4,500 meters. It'll then spend roughly 16 hours moving painstakingly slowly along the ocean floor, after which it will take another two hours to come back up.

Finally, downloading the data it has collected will take another four hours (and it's possible that none of the information it's gathered will even be useful). This will be done every day — in order to map the latest search zone, the sub will likely need a couple of months.

"We [will] start where we think the best location is, then go out from there," Houston told press. "If we don't find anything, we go further out and look a bit further afield."

But he added: "Don't be over optimistic, be realistic."

One potentially good sign for the search is another oil slick found Sunday, located in the same area as the pings were picked up last week. Nothing has, as of yet, been confirmed, but a sample is currently being analyzed to check whether it may have come from the missing plane.