work. that's one of the biggest problems in this search. the plane's transponder and the a car system that sends back data about the plane's health were apparently switched off. >> wouldn't surprise me that in the aftermath of this investigati investigation, a safety recommendation comes from the ntsb in this country, say you just have to put on a tracking system in every airliner that cannot be disabled. >> another piece of technology that could be due for an upgrade, flight data recorders. their batteries are only required to last 30 days and the signals they send have a range of only about two miles, making them difficult to find unless search teams are close by and lu lucky. >> let's talk a little more about the complications of upgrading these planes. and the cost. with andrew thomas, the founding editor in chief for the journal of transportation, security and