B737 FLT CREW WITH ZTL EXPERIENCED TCASII RA DURING CLB CLRNC FROM FL240 TO FL290.

Narrative

ZTL (125.62) CLRED FLT ACFT X FROM FL240 TO FL250; THEN TO FL290. BOTH PLTS HEARD THE ALT CLRNCS AND THEN READBACK CLRNCS AND WERE CONFIRMED AND THEN READBACK BY FO. EACH ALT WAS SET; THEN RESET ON MCP AND CONFIRMED BY CAPT. PASSING FL250 ACFT RECEIVED A TA WITH ANOTHER ACFT LESS THAN 20 MI ON RADAR SCREEN. ACFT SUBSEQUENTLY RECEIVED AN RA INITIALLY ACCOMPANIED BY 'MONITOR VERT SPD' AND RED VERT CLB WARNINGS; FOLLOWED BY 'DSND' COMMANDS. THE ACFT WAS IMMEDIATELY FLOWN INTO A DSCNT FROM FL250 TO FL240 IN RESPONSE TO RA COMMANDS. THE AUTOPLT WAS DISENGAGED DURING THE DSCNT. SIMULTANEOUSLY WITH THE RA COMMANDS; THE ATC CTLR SAID 'ACFT X; MAINTAIN FL240 AND WHAT ALT WERE YOU ASSIGNED?' WE RESPONDED FL290. THE CTLR SAID 'DSND IMMEDIATELY TO FL240 TFC AT 2 MI.' WE FOLLOWED RA COMMANDS TO FL240 AND RECEIVED 'CLR OF CONFLICT' AT FL240. PRIOR TO CONFLICT ACFT HAD BEEN CLRED AND WAS DIRECT TO SPA WITH LNAV AND VNAV ENGAGED AND AUTOPLT ON. WITHIN SEVERAL MINS OF CONFLICT RESOLUTION; CTLR VOICES CHANGED AND WE ASSUMED AN ACTUAL CTLR CHANGE HAD OCCURRED.