ACR X SAME ALT ASSIGNED TCASII TA RA HAD LTSS FROM ACFT Y. EVASIVE ACTION TAKEN CLB SYS ERROR.

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PHL APCH CTL HAD CLRED ACR X TO A HDG OF 090 DEGS AFTER PASSING BUCKS. WE ASKED FOR AND RECEIVED A DEV CLRNC TO THE R OF COURSE. WE WERE TOLD TO RETURN TO A HDG OF 090 DEGS WHEN CLR OF THE WX. WE WERE ON A DEV HDG OF 110 DEGS WHEN WE RECEIVED A TA FOLLOWED BY AN RA ALERT. PHL APCH WAS NOTIFIED OF OUR RA AND WE WERE COMPLYING. TCASII INSTRUCTED US TO CLB AT 1500 FPM. PHL APCH TOLD US TO TURN TO A HDG OF 060 DEGS FOLLOWED BY 360 DEGS. WE CLBED IN COMPLIANCE WITH THE TCASII RA. THE ALT WE REACHED WAS 8700 FT MSL BEFORE WE RECEIVED THE CLR OF CONFLICT SIGNAL WITH ACFT Y AND RETURNED TO 8000 FT MSL. AFTER LNDG I CALLED PHL APCH AND WAS TOLD THEY WERE INVESTIGATING A POSSIBLE OPERROR. SUPPLEMENTAL INFO FROM ACN 242797: WE DEVIATED BTWN 2 OR 3 SMALL CELLS WHICH REQUIRED SMALL CORRECTIONS FROM 090 DEGS TO 110 DEGS. THE CELLS WERE NOT SIGNIFICANT; BUT I WAS LOOKING FOR THE SMOOTHEST RIDE. THE CTLR THEN STATED THAT OPPOSITE DIRECTION TFC WAS CLBING TO OUR ALT; ASKED US TO TURN TO 090 DEGS; THEN 060 DEGS. ABOUT THIS TIME WE RECEIVED A TA ON OUR TCASII (YELLOW TARGET). THE ACFT AT 12 O'CLOCK AND ABOUT 5 MI. I INCREASED THE ANGLE OF BANK PAST 30 DEGS WHEN THE CTLR ASKED FOR A FURTHER L TURN TO 360 DEGS. WE RECEIVED AN RA TO CLB FROM PLUS 2000 FPM TO PLUS 2500 FPM. I COMPLIED; AND DEVIATED FROM ASSIGNED ALT; TO ABOUT 8700 FT. I RETURNED TO 8000 FT AFTER TFC WAS CLR (VIA TCASII). THE CTLR COULD HAVE BEEN A LITTLE MORE TIMELY; AND A TONE OF URGENCY MAY HAVE PROMPTED A MORE AGGRESSIVE TURN; EARLIER.