Narrative:

West (approximately 20 NM) of sea isle VOR (sie) we were given a clearance, 'be over sea isle in a descent to 5000 ft'. We were at 8000 ft assigned altitude and I asked my first officer to get clarification of when we were cleared to start our descent. He tried, but could not get a response from our controller before we arrived at sie VOR. (The controller was working other traffic on our VHF frequency, and additional traffic on another frequency because we could only hear parts of controller transmissions and none of the replies of some of the other traffic.) at sea isle VOR we were given a left turn to 040 degree about the same time as I started my descent to 5000 ft. During descent at approximately 7700 ft our TCASII sounded a TA followed immediately by a RA. TCASII system indicated climb 2000 FPM. It was clear ahead and above and I initiated a climb of 2000 FPM. (At this point I asked my first officer how close was the traffic and he replied 400 ft.) approximately 8500 ft warning stopped and I leveled off at 8700 ft and saw 2 fgt aircraft off my left wing slightly ahead, below and pulling away from me. I told my first officer to call ATC, tell them what we did and why, and I reinitiated my descent to 5000 ft and turn to 080 degree. I did not hear our controller acknowledge our call, but did hear the clearance to descend to 3000 ft, cleared for a VFR approach to atlantic city, and frequency change to atlantic city tower. We were given VFR single engine traffic while en route southwest of the airport, but we were not told of the fgt jet traffic. I called the ATC sector supervisor from our atlantic city operations office and was told that the fgt were returning from the warning area and were told to hold at 10000 ft for traffic, but they elected to cancel IFR clearance and continue to the airport VFR, and the span did not permit our controller to advise us of the VFR flight before our collision avoidance system was activated. It appears that the fgt were at 7500 ft headed northeast for atlantic city airport area when we were given the left turning descent over sea isle VOR and although they may have seen us, they were in our blind area below and slightly behind and right of us moving toward us and to our left. I believe our TCASII system prevented a potential collision.

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Original NASA ASRS Text

Title: FLC OF MLG RECEIVED TCASII RA AND CLBED TO AVOID VFR FGT IN VICINITY OF SIE VOR.

Narrative: W (APPROX 20 NM) OF SEA ISLE VOR (SIE) WE WERE GIVEN A CLRNC, 'BE OVER SEA ISLE IN A DSCNT TO 5000 FT'. WE WERE AT 8000 FT ASSIGNED ALT AND I ASKED MY FO TO GET CLARIFICATION OF WHEN WE WERE CLRED TO START OUR DSCNT. HE TRIED, BUT COULD NOT GET A RESPONSE FROM OUR CTLR BEFORE WE ARRIVED AT SIE VOR. (THE CTLR WAS WORKING OTHER TFC ON OUR VHF FREQ, AND ADDITIONAL TFC ON ANOTHER FREQ BECAUSE WE COULD ONLY HEAR PARTS OF CTLR TRANSMISSIONS AND NONE OF THE REPLIES OF SOME OF THE OTHER TFC.) AT SEA ISLE VOR WE WERE GIVEN A L TURN TO 040 DEG ABOUT THE SAME TIME AS I STARTED MY DSCNT TO 5000 FT. DURING DSCNT AT APPROX 7700 FT OUR TCASII SOUNDED A TA FOLLOWED IMMEDIATELY BY A RA. TCASII SYS INDICATED CLB 2000 FPM. IT WAS CLR AHEAD AND ABOVE AND I INITIATED A CLB OF 2000 FPM. (AT THIS POINT I ASKED MY FO HOW CLOSE WAS THE TFC AND HE REPLIED 400 FT.) APPROX 8500 FT WARNING STOPPED AND I LEVELED OFF AT 8700 FT AND SAW 2 FGT ACFT OFF MY L WING SLIGHTLY AHEAD, BELOW AND PULLING AWAY FROM ME. I TOLD MY FO TO CALL ATC, TELL THEM WHAT WE DID AND WHY, AND I REINITIATED MY DSCNT TO 5000 FT AND TURN TO 080 DEG. I DID NOT HEAR OUR CTLR ACKNOWLEDGE OUR CALL, BUT DID HEAR THE CLRNC TO DSND TO 3000 FT, CLRED FOR A VFR APCH TO ATLANTIC CITY, AND FREQ CHANGE TO ATLANTIC CITY TWR. WE WERE GIVEN VFR SINGLE ENG TFC WHILE ENRTE SW OF THE ARPT, BUT WE WERE NOT TOLD OF THE FGT JET TFC. I CALLED THE ATC SECTOR SUPVR FROM OUR ATLANTIC CITY OPS OFFICE AND WAS TOLD THAT THE FGT WERE RETURNING FROM THE WARNING AREA AND WERE TOLD TO HOLD AT 10000 FT FOR TFC, BUT THEY ELECTED TO CANCEL IFR CLRNC AND CONTINUE TO THE ARPT VFR, AND THE SPAN DID NOT PERMIT OUR CTLR TO ADVISE US OF THE VFR FLT BEFORE OUR COLLISION AVOIDANCE SYS WAS ACTIVATED. IT APPEARS THAT THE FGT WERE AT 7500 FT HEADED NE FOR ATLANTIC CITY ARPT AREA WHEN WE WERE GIVEN THE L TURNING DSCNT OVER SEA ISLE VOR AND ALTHOUGH THEY MAY HAVE SEEN US, THEY WERE IN OUR BLIND AREA BELOW AND SLIGHTLY BEHIND AND R OF US MOVING TOWARD US AND TO OUR L. I BELIEVE OUR TCASII SYS PREVENTED A POTENTIAL COLLISION.

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.