FLC OF MLG TOOK EVASIVE ACTION BY LEVELING OFF IN DSCNT IN RESPONSE TO A TCASII RA. THE OTHER ACFT MADE AN EVASIVE ACTION TURN.

Narrative

APCHING KANSAS CITY; ZKC GAVE US CLRNC TO DSND OUT OF OUR CRUISING ALT TO 12000 FT. DURING THE DSCNT WE WERE HANDED OFF TO APCH CTL; WHO SUBSEQUENTLY CLRED US TO 11000 FT AND CALLED TFC AT 10-11 O'CLOCK. WHEN WE RPTED A VISUAL ON THE TFC; AN ACR Y 737; APCH CLRED US TO 7000 FT. OUR SPD WAS ABOUT 310 KTS AND DECELERATING AND WE COMMENCED A LEVEL OFF AT 11000 FT TO LOSE AIRSPD AND ALLOW THE CLBING 737 (WHO WAS LEVELING AT 10000 FT) TO PASS BENEATH US. HOWEVER; SINCE WE WERE STILL DSNDING AND HE WAS STILL CLBING. TCASII GAVE BOTH ACFT A TA. WE FELT THERE WAS NO CONFLICT SINCE THERE WAS STILL AT LEAST 1000 FT OF SEPARATION AND WE WERE GOING TO MAINTAIN THAT UNTIL CLR. THE ACR Y 737 HAD ONLY HEARD THAT WE WERE CLRED TO 7000 FT AND THUS THOUGHT A CONFLICT WAS POSSIBLE. THEY INITIATED A SLIGHT R TURN (ABOUT 10 DEGS) TO FLY BEHIND US. GETTING INTO THIS SIT; EVERYONE WAS FOLLOWING THEIR ASSIGNED CLRNCS AND EVERYTHING APPEARED NORMAL. IN RETROSPECT; THERE WAS A BREAKDOWN OF COM SOMEWHERE IN THE CHAIN THAT LED TO AN UNNECESSARY DEV.