Narrative:

We were being vectored for climb from ewr en route to lax. Passing 7800 ft we were told to level at 8000 ft 'if able'. I leveled at 8070 ft. ATC issued a TA at '11 O'clock, 4 mi, 8500 ft'. A looked in that direction, and saw an aircraft momentarily. At the same time my first officer called 'TCASII TA'. I looked back inside and he immediately called 'RA'. I disconnected the autoplt, looked at the vertical speed indicator and realized that it was commanding me to descend at approximately 1500 FPM. I pushed the nose over to comply. Upon reaching approximately 7800 ft the RA disappeared. My first officer advised ATC that we had a TCASII RA and were complying with it. Another controller came on frequency and questioned us as to why we had complied with the RA when the traffic had been reported to us and that there was other traffic below us. I had seen an aircraft for 1-2 seconds. I did not call it in sight and did not know if it was the traffic causing the conflict. Since I no longer had visual contact, I followed the TCASII instructions. I felt that the controller did not understand my obligation in this situation as compared to a TCASII TA.

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Original NASA ASRS Text

Title: ACR WDB ALT DEV EXCURSION FROM CLRNC ALT IN RESPONSE TO TCASII RA. TRACON SUPVR QUESTIONS THE DEV IN VIEW OF THE FACT THAT A TA HAD BEEN GIVEN.

Narrative: WE WERE BEING VECTORED FOR CLB FROM EWR ENRTE TO LAX. PASSING 7800 FT WE WERE TOLD TO LEVEL AT 8000 FT 'IF ABLE'. I LEVELED AT 8070 FT. ATC ISSUED A TA AT '11 O'CLOCK, 4 MI, 8500 FT'. A LOOKED IN THAT DIRECTION, AND SAW AN ACFT MOMENTARILY. AT THE SAME TIME MY FO CALLED 'TCASII TA'. I LOOKED BACK INSIDE AND HE IMMEDIATELY CALLED 'RA'. I DISCONNECTED THE AUTOPLT, LOOKED AT THE VERT SPD INDICATOR AND REALIZED THAT IT WAS COMMANDING ME TO DSND AT APPROX 1500 FPM. I PUSHED THE NOSE OVER TO COMPLY. UPON REACHING APPROX 7800 FT THE RA DISAPPEARED. MY FO ADVISED ATC THAT WE HAD A TCASII RA AND WERE COMPLYING WITH IT. ANOTHER CTLR CAME ON FREQ AND QUESTIONED US AS TO WHY WE HAD COMPLIED WITH THE RA WHEN THE TFC HAD BEEN RPTED TO US AND THAT THERE WAS OTHER TFC BELOW US. I HAD SEEN AN ACFT FOR 1-2 SECONDS. I DID NOT CALL IT IN SIGHT AND DID NOT KNOW IF IT WAS THE TFC CAUSING THE CONFLICT. SINCE I NO LONGER HAD VISUAL CONTACT, I FOLLOWED THE TCASII INSTRUCTIONS. I FELT THAT THE CTLR DID NOT UNDERSTAND MY OBLIGATION IN THIS SITUATION AS COMPARED TO A TCASII TA.

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.