ACR X TCASII TA RA WITH ACR Y DSCNT THROUGH OCCUPIED ALT HAS LTSS. EVASIVE ACTION DSND.

Narrative

ACR X WHILE AT CRUISE ON J-110 65 MI SW OF STL AT FL280; WE RECEIVED A TA ON OUR TCASII I OBSERVED A YELLOW TARGET ON THE TCASII SCREEN AT 28.8 ALT DSNDING; (I HAD THE TCASII ON 20 M SCALE ON ALT.) THE ACFT WAS AT 12 O'CLOCK POS APPROX 15 MI AHEAD. THE CLOSURE RATE WAS HIGH AS WINDS WERE FROM W AT ABOUT 70 KTS. I VISUALLY SAW AN ACFT OUT OF OUR COCKPIT WINDOW COMING TOWARD US. WE RECEIVED AN RA SOON AFTER THE TA. THE TCASII SAID 'DSND; DSND.' AS THE CAPT (PF) BEGAN A DSCNT TOWARD THE GREEN BAND ON THE VSI THE TCASII SAID 'DSND NOW!' I THEN OBSERVED THE TCASII ACFT DISPLAY AT 28.4; STILL DSNDING; AND APPROX 6 MI AWAY. ATC CALLED US TO TURN TO 360 DEG HDG. I NOTIFIED HIM THAT WE WERE DSNDING IN RESPONSE TO AN RA AND WOULD TURN TO 360 DEG HDG; HIS RESPONSE WAS 'DO NOT DSND; TURN TO 360 DEG HDG.' THEN ATC ADVISED US TO STEEPEN THE TURN RATE. AS WE WERE IN A DSNDING TURN I OBSERVED THE RA TFC ON THE TCASII RIGHT UNDER THE AIRPLANE AND SYMBOL FOR OUR ACFT. I VISUALLY OBSERVED THE TFC PASS OUR L SIDE. ATC THEN GAVE US CLRNC TO DSND TO FL270. HE ALSO GAVE THE OTHER ACFT A CLB TO FL290. THE OTHER ACFT WAS XXXX. WE WERE LATER GIVEN CLRNC TO FL280 AND DIRECT TO BUM. WE ADVISED ATC OF OUR INTENTIONS TO FILE A 'NEAR MISS RPT' AS PER COMPANY PROC AND TO SAVE THE TRANSCRIPT TAPES.