Narrative:

ZLA cleared us to 17000 ft from FL220. ATC advised us of learjet at 1-2 O'clock position at 17500 ft. Did not have in sight. ATC told us we could level off higher, but we were already descending through 17500 ft and leveled off at 17000 ft. Received TCASII to descend. Started descent and then saw lear at 10 O'clock position above us at about 4 mi. Started to climb back to 17000 ft from about 16500 ft when ATC told us to contact socal approach. Socal told us to climb back to 17000 ft. I told them we had an RA and were climbing. About that time we had another TCASII to climb. Socal came back and said 'aircraft Z at 9 O'clock position at 16000 ft.' I again told them we had an RA and were climbing. I had aircraft Z in sight. No other transmission in regards to that traffic. Conclusion: we were sandwiched between 2 aircraft. One at 17500 ft and one at 16000 ft. We reacted to 2 TCASII RA's -- 1 to descend, and 1 to climb. I did not tell ZLA we were descending when we started down as I was looking for the lear and then got a TCASII to climb from the Z aircraft. Suggest keeping VFR traffic out of arrival corridor at altitudes near designated descent altitudes. Supplemental information from acn 450726: ZLA cleared us to 17000 ft from FL220. ATC advised us of traffic at 12-1 O'clock position at 17500 ft we did not have in sight. ZLA told us we could level off higher, but we were already passing through 17500 ft. Got a TCASII alert to descend and saw lear at 10 O'clock position and 4 mi. Started to climb back 17000 ft when we had another alert to climb. Socal approach said air carrier at 9 O'clock and 16000 ft. We reacted to 2 TCASII alerts.

Google
 

Original NASA ASRS Text

Title: MD80 CREW HAD A DOUBLE TCASII RA ON DSCNT INTO LAX.

Narrative: ZLA CLRED US TO 17000 FT FROM FL220. ATC ADVISED US OF LEARJET AT 1-2 O'CLOCK POS AT 17500 FT. DID NOT HAVE IN SIGHT. ATC TOLD US WE COULD LEVEL OFF HIGHER, BUT WE WERE ALREADY DSNDING THROUGH 17500 FT AND LEVELED OFF AT 17000 FT. RECEIVED TCASII TO DSND. STARTED DSCNT AND THEN SAW LEAR AT 10 O'CLOCK POS ABOVE US AT ABOUT 4 MI. STARTED TO CLB BACK TO 17000 FT FROM ABOUT 16500 FT WHEN ATC TOLD US TO CONTACT SOCAL APCH. SOCAL TOLD US TO CLB BACK TO 17000 FT. I TOLD THEM WE HAD AN RA AND WERE CLBING. ABOUT THAT TIME WE HAD ANOTHER TCASII TO CLB. SOCAL CAME BACK AND SAID 'ACFT Z AT 9 O'CLOCK POS AT 16000 FT.' I AGAIN TOLD THEM WE HAD AN RA AND WERE CLBING. I HAD ACFT Z IN SIGHT. NO OTHER XMISSION IN REGARDS TO THAT TFC. CONCLUSION: WE WERE SANDWICHED BTWN 2 ACFT. ONE AT 17500 FT AND ONE AT 16000 FT. WE REACTED TO 2 TCASII RA'S -- 1 TO DSND, AND 1 TO CLB. I DID NOT TELL ZLA WE WERE DSNDING WHEN WE STARTED DOWN AS I WAS LOOKING FOR THE LEAR AND THEN GOT A TCASII TO CLB FROM THE Z ACFT. SUGGEST KEEPING VFR TFC OUT OF ARR CORRIDOR AT ALTS NEAR DESIGNATED DSCNT ALTS. SUPPLEMENTAL INFO FROM ACN 450726: ZLA CLRED US TO 17000 FT FROM FL220. ATC ADVISED US OF TFC AT 12-1 O'CLOCK POS AT 17500 FT WE DID NOT HAVE IN SIGHT. ZLA TOLD US WE COULD LEVEL OFF HIGHER, BUT WE WERE ALREADY PASSING THROUGH 17500 FT. GOT A TCASII ALERT TO DSND AND SAW LEAR AT 10 O'CLOCK POS AND 4 MI. STARTED TO CLB BACK 17000 FT WHEN WE HAD ANOTHER ALERT TO CLB. SOCAL APCH SAID ACR AT 9 O'CLOCK AND 16000 FT. WE REACTED TO 2 TCASII ALERTS.

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.