Narrative:

Approaching kansas city, ZKC gave us clearance to descend out of our cruising altitude to 12000 ft. During the descent we were handed off to approach control, who subsequently cleared us to 11000 ft and called traffic at 10-11 O'clock. When we reported a visual on the traffic, an air carrier Y 737, approach cleared us to 7000 ft. Our speed was about 310 KTS and decelerating and we commenced a level off at 11000 ft to lose airspeed and allow the climbing 737 (who was leveling at 10000 ft) to pass beneath us. However, since we were still descending and he was still climbing. TCASII gave both aircraft 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 clear. The air carrier Y 737 had only heard that we were cleared to 7000 ft and thus thought a conflict was possible. They initiated a slight right turn (about 10 degrees) to fly behind us. Getting into this situation, everyone was following their assigned clrncs and everything appeared normal. In retrospect, there was a breakdown of communication somewhere in the chain that led to an unnecessary deviation.

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Original NASA ASRS Text

Title: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.