NEW : Investigators are yet to provide an explanation of why the plane flew way off course or pinpoint exactly where it ended up . nearly two dozen naval vessels begin the underwater search using listening technology . They focus on the `` area of highest probability '' of where the plane may have hit water . The overall search resumes ' Weeks with Two ships and aircraft . The search is `` the most difficult in human history , '' London 's Chandrika Sharma says .
NEW : nearly two dozen naval vessels begin the underwater search using listening technology . They focus on the `` area of highest probability '' of where the plane may have hit water . The overall search resumes ' Weeks with Two ships and aircraft . The search is `` the most difficult in human history , '' London 's Chandrika Sharma says .