Narrative:

Air carrier X, a B757, on FMS east side arrival to john wayne airport, uga Y, an AC12 on V8 east of sli at 5000 ft. Air carrier X was descending on profile to sna. Traffic was exchanged to each aircraft about each other repeatedly. Based on air carrier X's descent rate I felt there would be no problem. Air carrier X leveled off at 5000 ft, same altitude as uga Y. Air carrier X advised he had a TCASII RA to descend immediately. Air carrier X was advised traffic was no factor contact tower bottom line here, it was a bad judgement call on my part. I called traffic, looking to get visual separation and did not get it. But if an aircraft is on FMS east side arrival to sna and there is traffic on V8 at 5000 ft nebound and the controller does not take 1 of the aircraft off their route, this will happen every time, there will be a loss of separation. The aircraft will not hit, I had 1.42 mi in my case, but the controller will be held accountable. Supplemental information from acn 290985: TCASII idented an intruder over FO29L at 5000 ft. Our crossing altitude is 5100 ft. We were in clouds. TCASII gave us a RA of at least a 3000 FPM pitch down, which I did. I called socal upon arrival at sna and was advised that the tapes showed a miss of 1.42 NM at the same altitude. The area manager said there is a victor airway 3 NM north of FO29L of the east side arrival. The airway is not depicted on the east side one arrival chart, and the los angeles area chart does not show the east side one arrival track. So we have no way of even knowing of a potential conflict and the airway is only 3 mi away. That's too close. This needs to be fixed.

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Original NASA ASRS Text

Title: OPERROR.

Narrative: ACR X, A B757, ON FMS E SIDE ARR TO JOHN WAYNE ARPT, UGA Y, AN AC12 ON V8 E OF SLI AT 5000 FT. ACR X WAS DSNDING ON PROFILE TO SNA. TFC WAS EXCHANGED TO EACH ACFT ABOUT EACH OTHER REPEATEDLY. BASED ON ACR X'S DSCNT RATE I FELT THERE WOULD BE NO PROB. ACR X LEVELED OFF AT 5000 FT, SAME ALT AS UGA Y. ACR X ADVISED HE HAD A TCASII RA TO DSND IMMEDIATELY. ACR X WAS ADVISED TFC WAS NO FACTOR CONTACT TWR BOTTOM LINE HERE, IT WAS A BAD JUDGEMENT CALL ON MY PART. I CALLED TFC, LOOKING TO GET VISUAL SEPARATION AND DID NOT GET IT. BUT IF AN ACFT IS ON FMS E SIDE ARR TO SNA AND THERE IS TFC ON V8 AT 5000 FT NEBOUND AND THE CTLR DOES NOT TAKE 1 OF THE ACFT OFF THEIR RTE, THIS WILL HAPPEN EVERY TIME, THERE WILL BE A LOSS OF SEPARATION. THE ACFT WILL NOT HIT, I HAD 1.42 MI IN MY CASE, BUT THE CTLR WILL BE HELD ACCOUNTABLE. SUPPLEMENTAL INFO FROM ACN 290985: TCASII IDENTED AN INTRUDER OVER FO29L AT 5000 FT. OUR XING ALT IS 5100 FT. WE WERE IN CLOUDS. TCASII GAVE US A RA OF AT LEAST A 3000 FPM PITCH DOWN, WHICH I DID. I CALLED SOCAL UPON ARR AT SNA AND WAS ADVISED THAT THE TAPES SHOWED A MISS OF 1.42 NM AT THE SAME ALT. THE AREA MGR SAID THERE IS A VICTOR AIRWAY 3 NM N OF FO29L OF THE E SIDE ARR. THE AIRWAY IS NOT DEPICTED ON THE E SIDE ONE ARR CHART, AND THE LOS ANGELES AREA CHART DOES NOT SHOW THE E SIDE ONE ARR TRACK. SO WE HAVE NO WAY OF EVEN KNOWING OF A POTENTIAL CONFLICT AND THE AIRWAY IS ONLY 3 MI AWAY. THAT'S TOO CLOSE. THIS NEEDS TO BE FIXED.

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.