ALTDEV ALT EXCURSION DURING PLT FLC RESPONSE TO TCASII RA. EVASIVE ACTION DSCNT.

Narrative

A TA ADVISORY WAS RECEIVED WHILE ON RADAR VECTORS AT 9000 FT. THE ADVISORY WAS LEVEL AT +300 FT AT 1 O'CLOCK. THE TA WAS IMMEDIATELY FOLLOWED BY AN RA ADVISORY TO DSND; STILL SHOWING TFC LEVEL +300 FT. AS SOON AS THE DSCNT WAS STARTED; THE ADVISORY CANCELLED AND THE TARGET DISAPPEARED. NO TARGETS WERE SHOWING PRIOR TO THE TA. NO TFC WAS SIGHTED VISUALLY. THE FO ADVISED MKE APCH OF THE ALERT AND DSCNT AS WE LEVELED AT 8500 FT. APCH SAID THERE WAS NO TFC IN OUR AREA. HE THEN CLRED US TO 7000 FT FOR THE HDOF TO ORD APCH. AS WE LEVELED AT 7000 FT WE RECEIVED ANOTHER TA AND RA ADVISORY AT 12 O'CLOCK -2500 FT CLBING. THIS TFC WAS SPOTTED VISUALLY. IT WAS A HIGH PERFORMANCE SINGLE PULLING INTO A LOOP. NO DEV WAS MADE AND THE ADVISORY CANCELLED AS HE STARTED DOWN THE BACK SIDE OF THE LOOP. I HAVE NO IDEA IF THE ACFT DOING AEROBATICS COULD HAVE TRIGGERED THE ADVISORY AT 9000 MSL. JUDGING BY HIS SPD AND PERFORMANCE; HE MAY HAVE. PERHAPS THE RAPID ALT AND POS CHANGES OF HIS AEROBATICS CAUSED THE TCASII COMPUTER TO ISSUE A FALSE ADVISORY. MY EXPERIENCE WITH TCASII HAS BEEN POSITIVE. IT GIVES FAST; ACCURATE TFC INFO. PLUS IT GIVES YOU SOME INSIGHT AND RESPECT FOR THE CTLRS.