the split radar, like all atc radar, tracks primarily by aircraft transponder. so, when the split radar lost track of the ron brown aircraft, what was actually lost was the transponder return, as the aircraft was still there, on the approach path, although just starting to veer slightly left. now let's look at the awacs. the awacs system is designed to track non-transpondered targets. radar "hits" are placed in a computer system that keeps a list and tries to match the returns from the present radar sweep to the returns from the previous sweeps in order to generate meaningful target tracking data for the operators and weapons management systems. part of that process involves target to target comparisons to make certain that what the computer thinks is target xyz this sweep is the same target it thought was xyz last sweep. the total workload on the computer is a power function of the total number of non-transpondered targets being carried in the target list. if a target has a transponder, the awacs will track the target using the transponder return, because not only is less computer power needed for a transpondered target, but the workload for non-transpondered targets is reduced. how do we know that the awacs was tracking the ron brown plane via transponder? because the awacs lost it's track at the same time that the split radar lost it's transponder return. had the awacs been tracking the ron brown plane via skin-paint, there is no reason for it to lose track of the aircraft at the same time that split did, while the aircraft was still 7 miles from the crash site.
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