ACR X CLB TO OCCUPIED ALT HAD LTSS FROM ACR Y. TCASII RA EVASIVE ACTION TAKEN; STOP CLB.

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ACR X CLRED TO FILED ALT OF 5000 FT AFTER DEPARTING HARRISBURG INTL (MDT) ENRTE PHILADELPHIA (PHL). AFTER LEVELING AT 5000 FT; CREW REQUESTED AND WAS CLRED TO 7000 FT. WHILE CLBING THROUGH 6000 FT WE OBSERVED TCASII TFC LEVEL AT 7000 FT; 2 O'CLOCK AND CONVERGING. WE QUERIED HARRISBURG AS TO WHETHER THEY WERE HANDLING THE TFC AND GOT NO RESPONSE. WE STOPPED OUR CLB AT 6500 FT; WITH THE TFC IN SIGHT. WE ASKED HARRISBURG APCH AGAIN REGARDING THE TFC; AND THEY REPLIED; 'THANKS; I WAS TRYING TO COORDINATE YOUR CLB TO 7000 FT. MAINTAIN 6000 FT.' TCASII DID ISSUE A 'RA' BUT AS PER OUR OPS MANUAL; WE HAD ACR Y IN SIGHT (JETSTREAM 31) AND WERE ABLE TO MAINTAIN SEPARATION AND THUS WERE NOT OBLIGED TO COMPLY. THIS SEEMS (ON THE SURFACE) LIKE A SIMPLE 'HUMAN ERROR' EVENT. TCASII CAN BE LIFESAVER; LITERALLY. I HAVE COME TO QUESTION THE LOGIC IN OUR OPS MANUAL REGARDING NONCOMPLIANCE WITH RA'S WHEN VISUAL SEPARATION CAN BE MAINTAINED. SPECIFICALLY; IF 2 ACFT ARE RECEIVING COMPLIMENTARY RA'S AND 1 DOES NOT COMPLY; COULD A PROB BE CREATED OR WORSENED? OR DOES THE SOFTWARE ANTICIPATE THIS POSSIBILITY?