Narrative:

First officer was flying aircraft on warrd 2 arrival into ewr. We were given a clearance to cross holey intersection at 11000 ft, which is depicted on the arrival. Just south of holey at approximately 14000 ft during descent, center told us we had traffic at 12 O'clock, opp direction, 8 NM at 12500 ft. Our aircraft was TCASII equipped and we could verify the traffic was in the announced location. I advised center we were negative contact and wanted to level at 13000 ft until clear. I anticipated a conflict. The geometry didn't look good. From here on it got sort of confusing and I'm not sure what center said in reply to my wanting to level off at 13000 ft until clear of traffic. The first officer leveled off momentarily at 13000 ft and the center said the traffic would pass off our left. The TCASII indicated target was about 4-5 NM at approximately 11:30 position. We did not have a visibility on traffic. The first officer continued the descent (attempted to). I was outside looking visually and notice we were descending. Through 12800 ft at about 500 FPM. Simultaneously with me saying, 'no, stay at 13000 ft.' we got a TCASII RA advising a climb. I took the aircraft and immediately started a 500 FPM climb back to 13000 ft. There was no 'clear of conflict' TCASII advisory after traffic passed. I then advised center we would be unable to cross holey at 11000 ft and was told to 'just descend to 11000 ft.' I advised center we had experience a TCASII RA instruction, but didn't know if it was on previous traffic on some other unknown. We never got a visual on the traffic. If we had continued our descent to 11000 ft as originally cleared, the traffic would have been a serious threat. It was my initiative to level at 13000 ft that probably prevented a near miss. I'm not sure what center's criteria is on VFR vs IFR traffic for sep, but it appears it was non-merging returns. Anyway it was kind of lonely. I had a center controller and a first officer both trying to get us as close to traffic as they could. Radio traffic and controller workload on the frequency appeared light to moderate. I can't recall if 12500 ft traffic was on same frequency or if it had a visibility on us.

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Original NASA ASRS Text

Title: TCAS II RA. TRAFFIC NOT IN SIGHT. ACFT LEVELED AT 13000'. TRAFFIC WAS ISSUED BY ARTCC RADAR CTLR BEFORE THE RA. TRAFFIC AT 12500'.

Narrative: FO WAS FLYING ACFT ON WARRD 2 ARR INTO EWR. WE WERE GIVEN A CLRNC TO CROSS HOLEY INTXN AT 11000 FT, WHICH IS DEPICTED ON THE ARR. JUST S OF HOLEY AT APPROX 14000 FT DURING DSNT, CTR TOLD US WE HAD TFC AT 12 O'CLOCK, OPP DIRECTION, 8 NM AT 12500 FT. OUR ACFT WAS TCASII EQUIPPED AND WE COULD VERIFY THE TFC WAS IN THE ANNOUNCED LOCATION. I ADVISED CTR WE WERE NEGATIVE CONTACT AND WANTED TO LEVEL AT 13000 FT UNTIL CLR. I ANTICIPATED A CONFLICT. THE GEOMETRY DIDN'T LOOK GOOD. FROM HERE ON IT GOT SORT OF CONFUSING AND I'M NOT SURE WHAT CTR SAID IN REPLY TO MY WANTING TO LEVEL OFF AT 13000 FT UNTIL CLR OF TFC. THE FO LEVELED OFF MOMENTARILY AT 13000 FT AND THE CTR SAID THE TFC WOULD PASS OFF OUR LEFT. THE TCASII INDICATED TARGET WAS ABOUT 4-5 NM AT APPROX 11:30 POS. WE DID NOT HAVE A VIS ON TFC. THE FO CONTINUED THE DSNT (ATTEMPTED TO). I WAS OUTSIDE LOOKING VISUALLY AND NOTICE WE WERE DSNDING. THROUGH 12800 FT AT ABOUT 500 FPM. SIMULTANEOUSLY WITH ME SAYING, 'NO, STAY AT 13000 FT.' WE GOT A TCASII RA ADVISING A CLB. I TOOK THE ACFT AND IMMEDIATELY STARTED A 500 FPM CLB BACK TO 13000 FT. THERE WAS NO 'CLR OF CONFLICT' TCASII ADVISORY AFTER TFC PASSED. I THEN ADVISED CTR WE WOULD BE UNABLE TO CROSS HOLEY AT 11000 FT AND WAS TOLD TO 'JUST DSND TO 11000 FT.' I ADVISED CTR WE HAD EXPERIENCE A TCASII RA INSTRUCTION, BUT DIDN'T KNOW IF IT WAS ON PREVIOUS TFC ON SOME OTHER UNKNOWN. WE NEVER GOT A VISUAL ON THE TFC. IF WE HAD CONTINUED OUR DSNT TO 11000 FT AS ORIGINALLY CLRED, THE TFC WOULD HAVE BEEN A SERIOUS THREAT. IT WAS MY INITIATIVE TO LEVEL AT 13000 FT THAT PROBABLY PREVENTED A NEAR MISS. I'M NOT SURE WHAT CTR'S CRITERIA IS ON VFR VS IFR TFC FOR SEP, BUT IT APPEARS IT WAS NON-MERGING RETURNS. ANYWAY IT WAS KIND OF LONELY. I HAD A CTR CTLR AND A FO BOTH TRYING TO GET US AS CLOSE TO TFC AS THEY COULD. RADIO TFC AND CTLR WORKLOAD ON THE FREQ APPEARED LIGHT TO MODERATE. I CAN'T RECALL IF 12500 FT TFC WAS ON SAME FREQ OR IF IT HAD A VIS ON US.

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.