Narrative:

We were flying the arrival into the los angeles area at 7000 ft. I heard a transmission by approach control pointing out a '727 at 'X' O'clock to another aircraft. That aircraft responded with 'traffic in sight.' it was then cleared to descend. We received a TCASII TA on a nearby aircraft. This was followed by a traffic resolution to 'descend! Descend!' the captain immediately started a descent. The airwaves were filled with non-stop instructions and replies, but I managed to interject, 'approach, X descending due to TCASII.' approach control replied with something like, 'I don't recommend descending: we don't have control over that air space. The other aircraft has you in sight.' I examined our scope and advised the captain that the other aircraft was right on top of us. The captain started a right turn in addition to our descent. We were now at about 6000 ft and still descending. At some point I vaguely recall hearing, 'we lost sight of the aircraft.' I told the captain that the other aircraft was 300 ft and descending just to our left (according to our TCASII scope). I looked out his window and spotted a jetstream BA3100 slightly above and about 200-300 ft in our 9 O'clock position. We had already descended from 7000 ft to about 5800 ft, and turned right from the 068 radial to about 090 degrees. The RA had continued to sound 'descend! Descend!' during the entire situation. Naturally, it had been very tense in the cockpit, and I may have missed a possible, routine-toned. 'X turn right to 120.' I replied with 'roger, turning to 120 at 6000 ft.' the rest of the vectored approach and landing were uneventful. 1) we avoided an almost certain mid-air collision because of our TCASII instructions, our prompt action in following them, and our adding a turn to the 'descend!' RA. 2) although approach control apparently gave us a turn to 120 after we had done considerable maneuvering, it was far too late to have avoided the conflict! I certainly would like to have heard the first 'turn to 120' call: however, I think it was a bit too late to do much good. When the other aircraft said he had the traffic in sight, was that traffic us? Did he ever see us? Did he have a TCASII? If he did, was it giving him a TA and subsequently a RA? Why did approach control intentionally vector 2 aircraft so close together, even if 1 supposedly saw the other? We were flying a STAR, not a final approach to parallel runways.) why did approach control try to discourage us from descending to avoid a mid-air collision? But the jetstream and our B-727 targets must have been pretty close together on his radar screen! The controller did give us instructions to turn, but only well after the fact.

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Original NASA ASRS Text

Title: NMAC ON LAX VISUAL APCH.

Narrative: WE WERE FLYING THE ARR INTO THE LOS ANGELES AREA AT 7000 FT. I HEARD A XMISSION BY APCH CTL POINTING OUT A '727 AT 'X' O'CLOCK TO ANOTHER ACFT. THAT ACFT RESPONDED WITH 'TFC IN SIGHT.' IT WAS THEN CLRED TO DSND. WE RECEIVED A TCASII TA ON A NEARBY ACFT. THIS WAS FOLLOWED BY A TFC RESOLUTION TO 'DSND! DSND!' THE CAPT IMMEDIATELY STARTED A DSCNT. THE AIRWAVES WERE FILLED WITH NON-STOP INSTRUCTIONS AND REPLIES, BUT I MANAGED TO INTERJECT, 'APCH, X DSNDING DUE TO TCASII.' APCH CTL REPLIED WITH SOMETHING LIKE, 'I DON'T RECOMMEND DSNDING: WE DON'T HAVE CTL OVER THAT AIR SPACE. THE OTHER ACFT HAS YOU IN SIGHT.' I EXAMINED OUR SCOPE AND ADVISED THE CAPT THAT THE OTHER ACFT WAS RIGHT ON TOP OF US. THE CAPT STARTED A R TURN IN ADDITION TO OUR DSCNT. WE WERE NOW AT ABOUT 6000 FT AND STILL DSNDING. AT SOME POINT I VAGUELY RECALL HEARING, 'WE LOST SIGHT OF THE ACFT.' I TOLD THE CAPT THAT THE OTHER ACFT WAS 300 FT AND DSNDING JUST TO OUR L (ACCORDING TO OUR TCASII SCOPE). I LOOKED OUT HIS WINDOW AND SPOTTED A JETSTREAM BA3100 SLIGHTLY ABOVE AND ABOUT 200-300 FT IN OUR 9 O'CLOCK POS. WE HAD ALREADY DSNDED FROM 7000 FT TO ABOUT 5800 FT, AND TURNED R FROM THE 068 RADIAL TO ABOUT 090 DEGS. THE RA HAD CONTINUED TO SOUND 'DSND! DSND!' DURING THE ENTIRE SIT. NATURALLY, IT HAD BEEN VERY TENSE IN THE COCKPIT, AND I MAY HAVE MISSED A POSSIBLE, ROUTINE-TONED. 'X TURN R TO 120.' I REPLIED WITH 'ROGER, TURNING TO 120 AT 6000 FT.' THE REST OF THE VECTORED APCH AND LNDG WERE UNEVENTFUL. 1) WE AVOIDED AN ALMOST CERTAIN MID-AIR COLLISION BECAUSE OF OUR TCASII INSTRUCTIONS, OUR PROMPT ACTION IN FOLLOWING THEM, AND OUR ADDING A TURN TO THE 'DSND!' RA. 2) ALTHOUGH APCH CTL APPARENTLY GAVE US A TURN TO 120 AFTER WE HAD DONE CONSIDERABLE MANEUVERING, IT WAS FAR TOO LATE TO HAVE AVOIDED THE CONFLICT! I CERTAINLY WOULD LIKE TO HAVE HEARD THE FIRST 'TURN TO 120' CALL: HOWEVER, I THINK IT WAS A BIT TOO LATE TO DO MUCH GOOD. WHEN THE OTHER ACFT SAID HE HAD THE TFC IN SIGHT, WAS THAT TFC US? DID HE EVER SEE US? DID HE HAVE A TCASII? IF HE DID, WAS IT GIVING HIM A TA AND SUBSEQUENTLY A RA? WHY DID APCH CTL INTENTIONALLY VECTOR 2 ACFT SO CLOSE TOGETHER, EVEN IF 1 SUPPOSEDLY SAW THE OTHER? WE WERE FLYING A STAR, NOT A FINAL APCH TO PARALLEL RWYS.) WHY DID APCH CTL TRY TO DISCOURAGE US FROM DSNDING TO AVOID A MID-AIR COLLISION? BUT THE JETSTREAM AND OUR B-727 TARGETS MUST HAVE BEEN PRETTY CLOSE TOGETHER ON HIS RADAR SCREEN! THE CTLR DID GIVE US INSTRUCTIONS TO TURN, BUT ONLY WELL AFTER THE FACT.

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.