fees ya indonesia is going to look specifically at the tropical region there in the indian ocean. so we have some progress on that front. we're looking and we believe we're looking in the right place. we just haven't found it yet. john? >> it is a very big place to look. thank you, jim clancy live for us there. >>> there has been a lot of focus on the plane's acars, jim mentioned it. it stands for "aircraft communications addressing and reporting system" and investigators are trying to determine when exactly the system was turned off on flight 370. i guess more importantly, by who. we heard that from jim clancey. right now they simply dent know the answer. martin savage shows us what the acars does and how it works. >> reporter: with this particular airline mystery, a lot of people are learning a lot about technology that up until now most of us knew nothing about. case in point, the acars system. let me kind of try and walk and talk you through it. first of all, i can bring it up on this screen down here, watch, i'll push a bus on the. this is a simple menu and it works very much