Narrative:

Situation occurred during initial vectoring for approach after departing bucks intersection arrival fix. We were on vectors for an approach to 27R at phl. While level at 6000 ft heading 120 degree approximately 15 mi northwest of the airport. We were told to turn right heading 180. Controller called out VFR traffic Y at 1 O'clock, 5 mi, nwbound at 6500 ft en route to north philadelphia airport. Our TCASII was on the 10 mi range with numerous targets in that direction (which was toward phl international). All were white targets. TCASII was then switched to 5 mi range. Target Y just appeared on edge of TCASII picture as yellow. TCASII was switched to the 10 mi range to see the rest of the target information. It showed traffic Y now at 4 mi and closing, in a descent, and at 6300 ft TCASII gave a TA aurally. We queried the controller that the traffic was descending. Controller gave us a turn to heading 090 degree and replied that the traffic Y had apparently busted its altitude. Target Y now turned to a red target indicate at our altitude still descending. TCASII commanded 'monitor vertical speed.' we were now in a turn toward 090 degree (left turn). TCASII now commanded approximately 2000 FPM climb. Target Y was inside the 2 1/2 mi range ring. The copilot (who was at the controls), started the climb and continued to turn. I informed the controller that the target Y was at our altitude and we were climbing clear of the traffic. We climbed to 7000 ft and went to 7300 ft before stopping the climb. In the meantime the target Y indicated 5500 ft and behind us as it had passed off our right. Because we were in a turn, we did not see the traffic. After having informed controller we had a TCASII RA and had begun to climb, he declared he wasn't working the traffic but another controller was. After traffic Y was behind us he told us to descend back down to 6000 ft and change to the final controller's frequency. After landing I called the supervising controller to discuss the incident and was told the traffic Y was about 3 mi away and we had adequate separation. I informed him we were required to follow the TCASII RA commands and never did have the traffic Y in sight.

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Original NASA ASRS Text

Title: FLC OF ACR MLG RESPOND TO A TCASII RA WITH A VFR ACFT THAT DSNDED WITHOUT CLRNC.

Narrative: SITUATION OCCURRED DURING INITIAL VECTORING FOR APCH AFTER DEPARTING BUCKS INTXN ARR FIX. WE WERE ON VECTORS FOR AN APCH TO 27R AT PHL. WHILE LEVEL AT 6000 FT HDG 120 DEG APPROX 15 MI NW OF THE ARPT. WE WERE TOLD TO TURN R HDG 180. CTLR CALLED OUT VFR TFC Y AT 1 O'CLOCK, 5 MI, NWBOUND AT 6500 FT ENRTE TO N PHILADELPHIA ARPT. OUR TCASII WAS ON THE 10 MI RANGE WITH NUMEROUS TARGETS IN THAT DIRECTION (WHICH WAS TOWARD PHL INTL). ALL WERE WHITE TARGETS. TCASII WAS THEN SWITCHED TO 5 MI RANGE. TARGET Y JUST APPEARED ON EDGE OF TCASII PICTURE AS YELLOW. TCASII WAS SWITCHED TO THE 10 MI RANGE TO SEE THE REST OF THE TARGET INFO. IT SHOWED TFC Y NOW AT 4 MI AND CLOSING, IN A DSCNT, AND AT 6300 FT TCASII GAVE A TA AURALLY. WE QUERIED THE CTLR THAT THE TFC WAS DSNDING. CTLR GAVE US A TURN TO HDG 090 DEG AND REPLIED THAT THE TFC Y HAD APPARENTLY BUSTED ITS ALT. TARGET Y NOW TURNED TO A RED TARGET INDICATE AT OUR ALT STILL DSNDING. TCASII COMMANDED 'MONITOR VERT SPD.' WE WERE NOW IN A TURN TOWARD 090 DEG (L TURN). TCASII NOW COMMANDED APPROX 2000 FPM CLB. TARGET Y WAS INSIDE THE 2 1/2 MI RANGE RING. THE COPLT (WHO WAS AT THE CTLS), STARTED THE CLB AND CONTINUED TO TURN. I INFORMED THE CTLR THAT THE TARGET Y WAS AT OUR ALT AND WE WERE CLBING CLR OF THE TFC. WE CLBED TO 7000 FT AND WENT TO 7300 FT BEFORE STOPPING THE CLB. IN THE MEANTIME THE TARGET Y INDICATED 5500 FT AND BEHIND US AS IT HAD PASSED OFF OUR R. BECAUSE WE WERE IN A TURN, WE DID NOT SEE THE TFC. AFTER HAVING INFORMED CTLR WE HAD A TCASII RA AND HAD BEGUN TO CLB, HE DECLARED HE WASN'T WORKING THE TFC BUT ANOTHER CTLR WAS. AFTER TFC Y WAS BEHIND US HE TOLD US TO DSND BACK DOWN TO 6000 FT AND CHANGE TO THE FINAL CTLR'S FREQ. AFTER LNDG I CALLED THE SUPERVISING CTLR TO DISCUSS THE INCIDENT AND WAS TOLD THE TFC Y WAS ABOUT 3 MI AWAY AND WE HAD ADEQUATE SEPARATION. I INFORMED HIM WE WERE REQUIRED TO FOLLOW THE TCASII RA COMMANDS AND NEVER DID HAVE THE TFC Y IN SIGHT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.