Narrative:

During our descent to land at lgb, coast approach advised us of traffic somewhere between 12 and 2 O'clock. When this advisory was received, we were just north of el toro naval air station and in a descent passing 8000 ft to 7500 ft. The first officer idented traffic in this approximately position and the traffic was also being displayed on the TCASII. Shortly thereafter, an additional target appeared on the TCASII display at our 12 O'clock position. We were still descending and the target became a red square indicating 300 ft below our altitude. We immediately received an RA display and aural command climb, climb. Neither the first officer nor I could locate the conflicting traffic, but I began increasing thrust from idle and rotating the aircraft attitude toward a climb. The first officer advised coast approach control that we had a TCASII conflict warning and were being directed to climb. Our best recollection is that coast replied that they understood, and that we should not climb above 7500 ft MSL. I leveled the aircraft at about 6800 ft and climbed slightly to about 7000 ft. During this maneuver, the TCASII display cleared and the aural RA terminated. At that point, we continued our descent to the altitude to which we had been cleared. Subsequently, we experienced 2 more traffic displays which seemed to indicate potential traffic conflicts: one at 10-11 O'clock and minus 200 ft, and some time later, another at 9 O'clock at our altitude. We questioned approach control about the 9 O'clock traffic at our altitude and he stated there was not traffic at that position. Also, we never idented any traffic at 10-11 O'clock and minus 200 ft either visually or by notification from ATC when that warning occurred. In each case where these 'assumed false' indications were noted, there were legitimate idented (either by ATC or visually) targets being displayed on the TCASII. No avoidance actions were taken with respect to the latter 2 traffic displays and the targets disappeared. We continued our approach to lgb and landed without incident. There was a message when we arrived to call coast approach control and I spoke to controller supervisor. He stated that he understood we had a TCASII advisory but that IFR separation was lost during our level off at 7000 ft. The TCASII system provides us with an additional source of data for safer operation of our aircraft, but carries the additional requirement that we must be even more aware of the environment in which we are operating to insure that directed evasive actions which we take are not going to result in catastrophe.

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Original NASA ASRS Text

Title: POTENTIAL CONFLICT DURING EVASIVE ACTION CLB AFTER TCASII RA.

Narrative: DURING OUR DSCNT TO LAND AT LGB, COAST APCH ADVISED US OF TFC SOMEWHERE BTWN 12 AND 2 O'CLOCK. WHEN THIS ADVISORY WAS RECEIVED, WE WERE JUST N OF EL TORO NAVAL AIR STATION AND IN A DSCNT PASSING 8000 FT TO 7500 FT. THE FO IDENTED TFC IN THIS APPROX POS AND THE TFC WAS ALSO BEING DISPLAYED ON THE TCASII. SHORTLY THEREAFTER, AN ADDITIONAL TARGET APPEARED ON THE TCASII DISPLAY AT OUR 12 O'CLOCK POS. WE WERE STILL DSNDING AND THE TARGET BECAME A RED SQUARE INDICATING 300 FT BELOW OUR ALT. WE IMMEDIATELY RECEIVED AN RA DISPLAY AND AURAL COMMAND CLB, CLB. NEITHER THE FO NOR I COULD LOCATE THE CONFLICTING TFC, BUT I BEGAN INCREASING THRUST FROM IDLE AND ROTATING THE ACFT ATTITUDE TOWARD A CLB. THE FO ADVISED COAST APCH CTL THAT WE HAD A TCASII CONFLICT WARNING AND WERE BEING DIRECTED TO CLB. OUR BEST RECOLLECTION IS THAT COAST REPLIED THAT THEY UNDERSTOOD, AND THAT WE SHOULD NOT CLB ABOVE 7500 FT MSL. I LEVELED THE ACFT AT ABOUT 6800 FT AND CLBED SLIGHTLY TO ABOUT 7000 FT. DURING THIS MANEUVER, THE TCASII DISPLAY CLRED AND THE AURAL RA TERMINATED. AT THAT POINT, WE CONTINUED OUR DSCNT TO THE ALT TO WHICH WE HAD BEEN CLRED. SUBSEQUENTLY, WE EXPERIENCED 2 MORE TFC DISPLAYS WHICH SEEMED TO INDICATE POTENTIAL TFC CONFLICTS: ONE AT 10-11 O'CLOCK AND MINUS 200 FT, AND SOME TIME LATER, ANOTHER AT 9 O'CLOCK AT OUR ALT. WE QUESTIONED APCH CTL ABOUT THE 9 O'CLOCK TFC AT OUR ALT AND HE STATED THERE WAS NOT TFC AT THAT POS. ALSO, WE NEVER IDENTED ANY TFC AT 10-11 O'CLOCK AND MINUS 200 FT EITHER VISUALLY OR BY NOTIFICATION FROM ATC WHEN THAT WARNING OCCURRED. IN EACH CASE WHERE THESE 'ASSUMED FALSE' INDICATIONS WERE NOTED, THERE WERE LEGITIMATE IDENTED (EITHER BY ATC OR VISUALLY) TARGETS BEING DISPLAYED ON THE TCASII. NO AVOIDANCE ACTIONS WERE TAKEN WITH RESPECT TO THE LATTER 2 TFC DISPLAYS AND THE TARGETS DISAPPEARED. WE CONTINUED OUR APCH TO LGB AND LANDED WITHOUT INCIDENT. THERE WAS A MESSAGE WHEN WE ARRIVED TO CALL COAST APCH CTL AND I SPOKE TO CTLR SUPVR. HE STATED THAT HE UNDERSTOOD WE HAD A TCASII ADVISORY BUT THAT IFR SEPARATION WAS LOST DURING OUR LEVEL OFF AT 7000 FT. THE TCASII SYS PROVIDES US WITH AN ADDITIONAL SOURCE OF DATA FOR SAFER OP OF OUR ACFT, BUT CARRIES THE ADDITIONAL REQUIREMENT THAT WE MUST BE EVEN MORE AWARE OF THE ENVIRONMENT IN WHICH WE ARE OPERATING TO INSURE THAT DIRECTED EVASIVE ACTIONS WHICH WE TAKE ARE NOT GOING TO RESULT IN CATASTROPHE.

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.