the bluefin 21 and the flight for flight 370. the bluefin reached its depth then automatically turned back when it hit about 2.7 miles down into the ocean. apparently the ocean charts were wrong on land. so explain to us what that means. >> well, a couple of things. first of all, we should know that the bluefin functioned the tway should operate. all auvs have a maximum operating depth. if they doubelow that they risk collapsing in on themselves. for safe operations they picked that depth as a design criteria. so the issue in the ocean is that the bathinatry is not well understood. the best you have, things called soundings from ship that help you understand what the, the general area, but there are going to be regions that could be deeper. regions that will be more shallow. so the vehicle needs to be able to operate as best it can in that without risking loss.