Malaysia Airlines Flight 370 has now been missing for 37 days, and it's been several days since searchers detected a ping consistent with the plane's black-box locators. As has been frequently noted, the batteries that power the recorders' beacons are only supposed to last 30 days. So, while it's always hard to say anything definitive about the missing jet, it seems likely that the black boxes' signals have died.
"What they're hoping for is to get one more, maybe two more pings so they can do a triangulation of the sounds and try and narrow the [search] area," aviation expert Geoffrey Thomas told the Associated Press. Once officials are certain that they have heard the last of the pings, an underwater vehicle will be sent down into the Indian Ocean to look for Flight 370's wreckage. With a search area of about 500 square miles, finding anything could take quite a while: According to the AP, it will take the Bluefin-21 submersible six to eight weeks cover that patch of seabed.