Narrative:

After intermediate level off at 7000 ft MSL, ATC (ontario departure) called traffic at 12 O'clock below. TCASII showed traffic at 200 ft below and directed an RA climb of approximately 2000 FPM. (We never visually acquired this traffic -- it was hazy below.) as we climbed, an air carrier medium large transport was crossing above at what we believed was 10000 ft from left to right. (We had the medium large transport in sight the entire time.) at about this time the TCASII commanded an RA descent of approximately 1400 FPM. We pushed over and made a left, 30 degree bank turn and passed approximately 1.5-2.0 NM and approximately 500 ft below the other aircraft. I felt the captain responded relatively quickly to the traffic below. The first officer did a good job making a call to ATC that we were climbing from the resultant RA, but I learned that by deviating from assigned altitude in busy airspace, there's a good chance that you can immediately get an RA moving you back down to the initial altitude. I feel we responded fairly quickly to both RA's, but I'll be anticipating the second RA quicker the next time this happens.

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Original NASA ASRS Text

Title: CAPT OF ACR LGT ACFT RESPONDED TO TCASII RA RESULTING IN AN EXCURSION FROM ASSIGNED ALT.

Narrative: AFTER INTERMEDIATE LEVEL OFF AT 7000 FT MSL, ATC (ONTARIO DEP) CALLED TFC AT 12 O'CLOCK BELOW. TCASII SHOWED TFC AT 200 FT BELOW AND DIRECTED AN RA CLB OF APPROX 2000 FPM. (WE NEVER VISUALLY ACQUIRED THIS TFC -- IT WAS HAZY BELOW.) AS WE CLBED, AN ACR MLG WAS XING ABOVE AT WHAT WE BELIEVED WAS 10000 FT FROM L TO R. (WE HAD THE MLG IN SIGHT THE ENTIRE TIME.) AT ABOUT THIS TIME THE TCASII COMMANDED AN RA DSCNT OF APPROX 1400 FPM. WE PUSHED OVER AND MADE A L, 30 DEG BANK TURN AND PASSED APPROX 1.5-2.0 NM AND APPROX 500 FT BELOW THE OTHER ACFT. I FELT THE CAPT RESPONDED RELATIVELY QUICKLY TO THE TFC BELOW. THE FO DID A GOOD JOB MAKING A CALL TO ATC THAT WE WERE CLBING FROM THE RESULTANT RA, BUT I LEARNED THAT BY DEVIATING FROM ASSIGNED ALT IN BUSY AIRSPACE, THERE'S A GOOD CHANCE THAT YOU CAN IMMEDIATELY GET AN RA MOVING YOU BACK DOWN TO THE INITIAL ALT. I FEEL WE RESPONDED FAIRLY QUICKLY TO BOTH RA'S, BUT I'LL BE ANTICIPATING THE SECOND RA QUICKER THE NEXT TIME THIS HAPPENS.

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.