Narrative:

While being vectored to intercept the localizer for 25R at lax, we received a clearance to fly a heading and altitude to intercept the final approach course (I think the heading was approximately 270 degrees, and the altitude 2500' MSL). Shortly after this, as we were intercepting final, the TCASII system broadcast an audio alert for traffic, and directed us to descend. We followed TCASII guidance and descended to approximately 2300', at which point the TCASII notified the conflict was over (we were IMC during this time). This avoidance action was noted by the controller (either by our slight altitude deviation or by the fact that we did not fly the final approach correctly). When the captain reported what we were doing to the controller, the controller told us to let him know before we followed TCASII guidance next time so he could tell us whether or not to follow it. The captain replied that we are directed to follow TCASII guidance. After landing, the ground controller told us on the radio to contact the TRACON (about the incident). When my captain contacted TRACON, a different, more senior controller told my captain that we were not in any trouble for deviating from assigned altitude, and that the other controller was incorrect for asking us to notify him in advance of following TCASII directives (to obtain some type of approval to follow TCASII guidance). This senior controller said the controller in question had been corrected. As far as recommendations, I simply suggest that controllers be made aware of current pilot guidance to follow TCASII guidance, even if it results in deviating from the assigned clearance (and also, false TCAS alerts for simultaneous approach traffic be rectified. I don't know if this was why we got our warning). I should also add that following the TCASII guidance while intercepting final, along with the ensuing confusion with the controller, resulted in terminating the first approach and received vectors for a second ILS form which we landed. Also, because of 2 simultaneous minor aircraft malfunctions at this same time (a HSI problem for the first officer and an air conditioning pack malfunction) we were rather busy in the cockpit, and none of us even had time to look at the TCAS scope to see the aircraft providing the conflict. All we did was follow the command on the vertical velocity indicator and audio warning to descend.

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Original NASA ASRS Text

Title: TCASII RESOLUTION RESULTS IN A CONFLICT WITH APCH CTL.

Narrative: WHILE BEING VECTORED TO INTERCEPT THE LOC FOR 25R AT LAX, WE RECEIVED A CLRNC TO FLY A HDG AND ALT TO INTERCEPT THE FINAL APCH COURSE (I THINK THE HDG WAS APPROX 270 DEGS, AND THE ALT 2500' MSL). SHORTLY AFTER THIS, AS WE WERE INTERCEPTING FINAL, THE TCASII SYS BROADCAST AN AUDIO ALERT FOR TFC, AND DIRECTED US TO DSND. WE FOLLOWED TCASII GUIDANCE AND DSNDED TO APPROX 2300', AT WHICH POINT THE TCASII NOTIFIED THE CONFLICT WAS OVER (WE WERE IMC DURING THIS TIME). THIS AVOIDANCE ACTION WAS NOTED BY THE CTLR (EITHER BY OUR SLIGHT ALT DEVIATION OR BY THE FACT THAT WE DID NOT FLY THE FINAL APCH CORRECTLY). WHEN THE CAPT RPTED WHAT WE WERE DOING TO THE CTLR, THE CTLR TOLD US TO LET HIM KNOW BEFORE WE FOLLOWED TCASII GUIDANCE NEXT TIME SO HE COULD TELL US WHETHER OR NOT TO FOLLOW IT. THE CAPT REPLIED THAT WE ARE DIRECTED TO FOLLOW TCASII GUIDANCE. AFTER LNDG, THE GND CTLR TOLD US ON THE RADIO TO CONTACT THE TRACON (ABOUT THE INCIDENT). WHEN MY CAPT CONTACTED TRACON, A DIFFERENT, MORE SENIOR CTLR TOLD MY CAPT THAT WE WERE NOT IN ANY TROUBLE FOR DEVIATING FROM ASSIGNED ALT, AND THAT THE OTHER CTLR WAS INCORRECT FOR ASKING US TO NOTIFY HIM IN ADVANCE OF FOLLOWING TCASII DIRECTIVES (TO OBTAIN SOME TYPE OF APPROVAL TO FOLLOW TCASII GUIDANCE). THIS SENIOR CTLR SAID THE CTLR IN QUESTION HAD BEEN CORRECTED. AS FAR AS RECOMMENDATIONS, I SIMPLY SUGGEST THAT CTLRS BE MADE AWARE OF CURRENT PLT GUIDANCE TO FOLLOW TCASII GUIDANCE, EVEN IF IT RESULTS IN DEVIATING FROM THE ASSIGNED CLRNC (AND ALSO, FALSE TCAS ALERTS FOR SIMULTANEOUS APCH TFC BE RECTIFIED. I DON'T KNOW IF THIS WAS WHY WE GOT OUR WARNING). I SHOULD ALSO ADD THAT FOLLOWING THE TCASII GUIDANCE WHILE INTERCEPTING FINAL, ALONG WITH THE ENSUING CONFUSION WITH THE CTLR, RESULTED IN TERMINATING THE FIRST APCH AND RECEIVED VECTORS FOR A SECOND ILS FORM WHICH WE LANDED. ALSO, BECAUSE OF 2 SIMULTANEOUS MINOR ACFT MALFUNCTIONS AT THIS SAME TIME (A HSI PROB FOR THE F/O AND AN AIR CONDITIONING PACK MALFUNCTION) WE WERE RATHER BUSY IN THE COCKPIT, AND NONE OF US EVEN HAD TIME TO LOOK AT THE TCAS SCOPE TO SEE THE ACFT PROVIDING THE CONFLICT. ALL WE DID WAS FOLLOW THE COMMAND ON THE VERT VELOCITY INDICATOR AND AUDIO WARNING TO DSND.

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.