ACR FOLLOWS TCASII RA NEAR BUNTS INTXN; PA. CTLR DOUBTS THE NEED SO TCASII EQUIP IS CHKED AND FOUND OK ON ARR.

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A FEW MI PAST BUNTS INTXN; FLT WAS ADVISED OF A VFR TFC 500 FT BELOW; 12 O'CLOCK POS. CREW BEGAN ACTIVELY SCANNING FOR THE TFC; HOWEVER; VISUAL CONTACT WAS NEVER ACQUIRED DUE IN PART TO A CLOUD BELOW OUR ACFT. ATIS IN PHL WAS CALLING FOR A FEW CLOUDS AT 6000 FT. TFC DID IN FACT DISPLAY ON TCASII. WHEN WITHIN 1 MI OR SO; ACFT DISPLAY STARTED TO SHOW A CLB AND TCASII GENERATED AN RA. THE PF (FO) COMPLIED WITH RA IMMEDIATELY. AT THE CLOSEST POINT; ACFT SHOWED WITHIN 200 FT OF OUR ACFT AND STILL DISPLAYED A CLB. WE CLBED APPROX 700 FT AND THEN WHEN THE RA WENT AWAY; CAME BACK DOWN TO OUR ORIGINAL ALT OF 7000 FT. THE PNF (CAPT) ADVISED ATC OF THE RA. ATC REPLIED THAT THEY NEVER SHOWED THE VFR ACFT IN A CLB AND SEEMED TO DOUBT THE CREW'S RPT. UPON LNDG; THE CAPT CALLED MAINT TO VERIFY TCASII PROPER OP. THEN THE CAPT CALLED TRACON AND WAS TOLD BY THE MGR ON DUTY THAT THE CTLR INVOLVED IN THIS INCIDENT WAS IN FACT FILING A RPT IN ORDER TO CLARIFY THIS EVENT IF NEEDED; AND IN THE INTEREST OF SAFETY IMPROVEMENT FOR SIMILAR SITS; THE CAPT ASKED MAINT TO SOMEHOW KEEP A RECORD OF THE RA. SUPPLEMENTAL INFO FROM ACN 450599: MAINT; AFTER PERFORMING NUMEROUS CHKS ON THE TCASII; DECLARED IT TO BE WORKING NORMALLY AND CLRED THE CAPT'S WRITE-UP IN THE ACFT'S LOGBOOK.