different area, about 300 miles away. officials cannot confirm anything that has been heard over the last 48 hours is connected to this plane. want to dig into what this latest information can actually mean for the search. i'm joined now by expeditions logistics specialists christine dennison. cnn's michael kay. and thomas alshiler, telemanager of bp design systems which designs and builds the black box pingers and also the pinger detectors. perhaps you can tell me what the job is now. now that we've had these two very promising detections, marchly from the ocean shield, because it seems to be the longest, the two-hour ping followed by the 15-minute ping that had the echo. what's the job now for the ocean shield? what are they trying to do? >> they're trying to do -- kind of cover the area and narrow where they thing the ping's coming from. they need to shrink the box they're going to look in when they put the vehicle down.