Searching nearly 500,000 square nautical miles for Flight 370

(CNN) – Search crews will be back over the southern Indian Ocean looking for any sign of the doomed Malaysia Airlines Flight 370, with time running out before the flight data and cockpit voice recorder, the so-called black box, stops "pinging."

Searchers continue to scour the area with high tech military equipment, as well as good old fashioned eyeballs out a window, but how do they figure out where to look and what's the priority?

CNN's Tom Foreman reports.