Bluefin-21

Bluefin-21

Leut Kelli Lunt/Australia Department of Defence via Getty Images

In this handout image provided by Australia's Department of Defence, Phoenix Autonomous Underwater Vehicle (AUV) Bluefin-21 is in the water after being craned over the side of Australian Defence Vessel Ocean Shield to begin using its side scan sonar in the search for the missing Malaysia Airlines flight MH370 on April 14, 2014.