latest. david? >> reporter: hi, gregg. yes, it's five weeks now since the malaysian airlines jet went missing with 239 people on board. and it's now become a race against time to find its black boxes before their batteries expire. ships and planes have today been searching two smaller areas of about 18,000 square miles in the indian ocean west of perth, australia. the search area has narrowed considerably over the past week after signals from the black boxes were detected. but no signals were found today. the last confirmed signals were detected back on tuesday. australian prime minister, tony abbott, warned it wouldn't be easy to recover the black boxes. >> while we do have a high degree of confidence that the transmissions that we've been picking up are from flight mh-370's black box recorder, no one should underestimate the