On 7/18/2015 8:40 PM, son_of_flubber wrote:
http://www.ntsb.gov/_layouts/ntsb.av...15FA259A&rpt=p

To me, this is the crucial passage:
"At 1100:49, the radar target of the F-16 was located 1/2 nautical mile
northeast of the Cessna, at an indicated altitude of 1,500 feet, and was
on an approximate track of 215 degrees. At that time, the Cessna
reported an indicated altitude of 1,400 feet, and was established on an
approximate track of 110 degrees. At 1100:52 the controller advised the
F-16 pilot, "traffic passing below you 1,400 feet." "

I find transponder-reported altitudes to be pretty notoriously
inaccurate in general. So it seems to me that these two planes
indicating only 100 feet apart (but only reporting their altitudes in
100 feet increments) should have been considered at the SAME altitude.

With my PCAS, I consider +/- 400 to be the same altitude.