Narrative:

We were flying downwind at 6000 ft for a visual approach to runway 27 at lindberg field; san diego. I (captain) was PF with autoplt off and autothrottles on. There was a military aircraft on the same frequency (socal) with call sign aircraft Y that was requesting a PAR into north island. Socal gave us a call 'air carrier X descend immediately to 5000 ft.' I pulled throttles to idle and pushed the nose over to start a descent and immediately got a TCASII RA to climb. I responded to the RA and had the first officer advise socal that we were climbing in response to an RA. As soon as a positive vertical speed was achieved; the RA changed to 'descend; descend.' so I responded to that RA. So at this point the aircraft had gone from a level attitude to an assertive nose down and idle attitude (in response to 'descend immediately') to an aggressive power on and nose up in response to a 'climb; climb' RA back to aggressive nose down; idle in response to the second RA. At this point I picked up visually the aircraft that was causing the RA. It was a military jet. I am pretty sure it was a T45. My assessment of the T45 from the visual sighting is that he transitioned from a high rate of descent to a slight climb. At the point of merge; I assess that the T45 was approximately 800-1000 ft above us in a l-hand turn and a possible slight climb. Socal made a comment that the close pass could have been avoided if we would have descended immediately. I responded on the radio that we climbed in response to a climbing RA. His response was that the RA was giving us bad information. We landed in san uneventfully. The passenger and flight attendants told us that it was very disconcerting in the back during the descent; climb; descent maneuver. After a quick turnaround; we flew back to sfo. The first officer called socal and talked to the supervisor at the time of the close pass. From the information gained from that phone call; combined with the actual close pass; the following is my assessment of what happened. As we were flying east at 6000 ft; the T45 was east of us at a higher altitude traveling west toward us. Socal gave the T45 a clearance to descend to an altitude of 6000 ft or possibly lower. The T45 descended at a rate much greater than the controller expected and quickly became a factor to us. At the time the controller gave us a 'descend immediately' call; the TCASII assessed the high rate of descent of the T45 and close proximity (approximately 500 ft above us) and gave us a climb command. I think the TCASII assessed that even with us below the T45 and descending; that a collision was still pending due to the high rate of descent of the T45. As we responded to the RA; the T45 stopped the high rate of descent to level or a possible climb. The TCASII then assessed that our RA induced climb could cause another potential collision and reversed from 'climb; climb' to 'descend; descend' at which time we followed the command.

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Original NASA ASRS Text

Title: A319 ON DOWNWIND FOR RWY 27 AT SAN AT 6000 FT EXPERIENCED TCASII RA WITH MIL ACFT; BOTH ACFT UNDER SCT TRACON CTL.

Narrative: WE WERE FLYING DOWNWIND AT 6000 FT FOR A VISUAL APCH TO RWY 27 AT LINDBERG FIELD; SAN DIEGO. I (CAPT) WAS PF WITH AUTOPLT OFF AND AUTOTHROTTLES ON. THERE WAS A MIL ACFT ON THE SAME FREQ (SOCAL) WITH CALL SIGN ACFT Y THAT WAS REQUESTING A PAR INTO NORTH ISLAND. SOCAL GAVE US A CALL 'ACR X DSND IMMEDIATELY TO 5000 FT.' I PULLED THROTTLES TO IDLE AND PUSHED THE NOSE OVER TO START A DSCNT AND IMMEDIATELY GOT A TCASII RA TO CLB. I RESPONDED TO THE RA AND HAD THE FO ADVISE SOCAL THAT WE WERE CLBING IN RESPONSE TO AN RA. AS SOON AS A POSITIVE VERT SPD WAS ACHIEVED; THE RA CHANGED TO 'DSND; DSND.' SO I RESPONDED TO THAT RA. SO AT THIS POINT THE ACFT HAD GONE FROM A LEVEL ATTITUDE TO AN ASSERTIVE NOSE DOWN AND IDLE ATTITUDE (IN RESPONSE TO 'DSND IMMEDIATELY') TO AN AGGRESSIVE PWR ON AND NOSE UP IN RESPONSE TO A 'CLB; CLB' RA BACK TO AGGRESSIVE NOSE DOWN; IDLE IN RESPONSE TO THE SECOND RA. AT THIS POINT I PICKED UP VISUALLY THE ACFT THAT WAS CAUSING THE RA. IT WAS A MIL JET. I AM PRETTY SURE IT WAS A T45. MY ASSESSMENT OF THE T45 FROM THE VISUAL SIGHTING IS THAT HE TRANSITIONED FROM A HIGH RATE OF DSCNT TO A SLIGHT CLB. AT THE POINT OF MERGE; I ASSESS THAT THE T45 WAS APPROX 800-1000 FT ABOVE US IN A L-HAND TURN AND A POSSIBLE SLIGHT CLB. SOCAL MADE A COMMENT THAT THE CLOSE PASS COULD HAVE BEEN AVOIDED IF WE WOULD HAVE DSNDED IMMEDIATELY. I RESPONDED ON THE RADIO THAT WE CLBED IN RESPONSE TO A CLBING RA. HIS RESPONSE WAS THAT THE RA WAS GIVING US BAD INFO. WE LANDED IN SAN UNEVENTFULLY. THE PAX AND FLT ATTENDANTS TOLD US THAT IT WAS VERY DISCONCERTING IN THE BACK DURING THE DSCNT; CLB; DSCNT MANEUVER. AFTER A QUICK TURNAROUND; WE FLEW BACK TO SFO. THE FO CALLED SOCAL AND TALKED TO THE SUPVR AT THE TIME OF THE CLOSE PASS. FROM THE INFO GAINED FROM THAT PHONE CALL; COMBINED WITH THE ACTUAL CLOSE PASS; THE FOLLOWING IS MY ASSESSMENT OF WHAT HAPPENED. AS WE WERE FLYING E AT 6000 FT; THE T45 WAS E OF US AT A HIGHER ALT TRAVELING W TOWARD US. SOCAL GAVE THE T45 A CLRNC TO DSND TO AN ALT OF 6000 FT OR POSSIBLY LOWER. THE T45 DSNDED AT A RATE MUCH GREATER THAN THE CTLR EXPECTED AND QUICKLY BECAME A FACTOR TO US. AT THE TIME THE CTLR GAVE US A 'DSND IMMEDIATELY' CALL; THE TCASII ASSESSED THE HIGH RATE OF DSCNT OF THE T45 AND CLOSE PROX (APPROX 500 FT ABOVE US) AND GAVE US A CLB COMMAND. I THINK THE TCASII ASSESSED THAT EVEN WITH US BELOW THE T45 AND DSNDING; THAT A COLLISION WAS STILL PENDING DUE TO THE HIGH RATE OF DSCNT OF THE T45. AS WE RESPONDED TO THE RA; THE T45 STOPPED THE HIGH RATE OF DSCNT TO LEVEL OR A POSSIBLE CLB. THE TCASII THEN ASSESSED THAT OUR RA INDUCED CLB COULD CAUSE ANOTHER POTENTIAL COLLISION AND REVERSED FROM 'CLB; CLB' TO 'DSND; DSND' AT WHICH TIME WE FOLLOWED THE COMMAND.

Data retrieved from NASA's ASRS site as of January 2009 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.