If it was really that close wouldn't there have been a TCAS resolution by the AAL?
That's a good point, and it prompted me to try and learn more about TCAS. From what I read, an aircraft in level flight won't get an RA as early as one that's climbing or descending. On Passur's site, AAl maintains 6000 for one minute and six seconds prior to the targets merging. In that same timespan BKA climbs 2500 feet. Maybe AAL got a "do not descend" RA? (Oddly, just after the flight paths cross, AAL descends to 5900, and then climbs back to and maintains 6000 for another 27 seconds.) (And, yes, I understand that either or both transponder(s) could be reporting as much as 200 feet off.)
The fact that BKA subsequently says he was "still level at 5000 when he passed over us", even though the radar depiction clearly shows otherwise, has me siding with the AAL captain.