quickly right after the incident. >> everything right now indicates this was a mistake. they didn't know what they were shooting at. the rebels thought it was a ukrainian military plane, a cargo plane. if they were using this equipment correctly, is that mistake possible? >> not really. the fact they shot a civilian airliner is very troubling, but they're probably not using the entire system. it consists of four components. one of those components is an air surveillance radar. that's capable of determining what your target is, whether it is a civilian aircraft or not. it has a transponder that would receive the code from the aircraft that would say, i'm a