CLRED FOR DSCNT WHEN TCASII RA ISSUED. DELAY DSCNT.

Narrative

WHILE ON A R DOWNWIND AT 11000 FT MSL; IN LEVEL FLT; AT APPROX 210 KIAS; WE RECEIVED A TCASII RA WHICH VERBALLY INSTRUCTED US TO 'CLB; CLB' ETC; AND THE IVSI GUIDANCE LIGHTS INSTRUCTED US TO INITIATE A CLB AT APPROX 300 PLUS FPM OR BETTER. WE WERE IN CLR DAYLIGHT VISUAL CONDITIONS AND I COULD SEE THE ACFT CAUSING THE RA. THE ALERT ACFT WAS CLBING AT A HIGH RATE (MLG) TO THEIR INITIAL CLB ALT OF 10000 FT; WHICH IS STANDARD FOR ALL DFW AREA TURBOJET DEPS. THESE TYPES OF SITS STILL OCCUR FAIRLY FREQUENTLY AT DFW. IN OUR CASE; I INFORMED ATC WE HAD AN RA AND THE CAPT (PF) DELAYED OUR PREVIOUSLY ISSUED DSCNT FOR APPROX 30 SECONDS OR SO (JUST PRIOR TO THE RA WE HAD BEEN CLRED DOWN TO 6000 FT MSL). AFTER THE RA; I THEN SPOTTED THE ACFT VISUALLY WITH REF TO THE TCASII DISPLAY AND INFORMED ATC. THE CTLR WAS QUITE BUSY AND SOUNDED SOMEWHAT 'ANXIOUS' ABOUT THE DELAY IN INITIATING OUR DSCNT; POSSIBLY DUE TO OTHER (UNKNOWN TO US) PROJECTED CONFLICTING ACFT OR DUE TO 'SHORT FINAL' OR 'SLAM DUNK' OPS IN PROGRESS. IT IS UNKNOWN TO US; BUT ANOTHER POSSIBLY GREATER CONFLICT COULD HAVE OCCURRED IF WE HAD RAPIDLY 'PULLED-UP' AND INITIATED A CLB IN THIS VERY BUSY AIRSPACE.