Narrative:

I was working the PM2 position at sct, los angeles area and a B737 on 10 mi final checked on frequency. The PM1 controller noticed the A310 on final for runway 25L had left the localizer and entered the ntz on about the 11 mi final. At that point I issued a traffic alert to the B737 and instructed the pilot to turn right heading 270 degrees. PM1 turned the A310 south and the conflict was resolved. Supplemental information from acn 375120: I spoke to the los angeles TRACON supervisor on duty. He said that we were drifting north of course and that separation from a B737 inbound to runway 24R was not adequate. He said that he would call me if a report would be filed. Our indications were centered on both localizer and navigation display. I wrote up the aircraft as such. Approach check confirmed 109.9 for runway 25L and the FMS runway 25L was briefed and crosschecked. Supplemental information from acn 375196: I saw the B737 and mentioned it to the captain. It was below us about 400 ft and approximately 3/4 of a mi to our right. It was not converging with us in my opinion at the time of the wave-off. We subsequently wrote the aircraft up for a possible ILS problem with our maintenance department.

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Original NASA ASRS Text

Title: PLTDEV LTSS WHEN A310 DRIFTED N OF THE RWY 25L APCH COURSE AND CONFLICTED WITH A B737 ON APCH TO RWY 24R.

Narrative: I WAS WORKING THE PM2 POS AT SCT, LOS ANGELES AREA AND A B737 ON 10 MI FINAL CHKED ON FREQ. THE PM1 CTLR NOTICED THE A310 ON FINAL FOR RWY 25L HAD LEFT THE LOC AND ENTERED THE NTZ ON ABOUT THE 11 MI FINAL. AT THAT POINT I ISSUED A TFC ALERT TO THE B737 AND INSTRUCTED THE PLT TO TURN R HDG 270 DEGS. PM1 TURNED THE A310 S AND THE CONFLICT WAS RESOLVED. SUPPLEMENTAL INFO FROM ACN 375120: I SPOKE TO THE LOS ANGELES TRACON SUPVR ON DUTY. HE SAID THAT WE WERE DRIFTING N OF COURSE AND THAT SEPARATION FROM A B737 INBOUND TO RWY 24R WAS NOT ADEQUATE. HE SAID THAT HE WOULD CALL ME IF A RPT WOULD BE FILED. OUR INDICATIONS WERE CTRED ON BOTH LOC AND NAV DISPLAY. I WROTE UP THE ACFT AS SUCH. APCH CHK CONFIRMED 109.9 FOR RWY 25L AND THE FMS RWY 25L WAS BRIEFED AND XCHKED. SUPPLEMENTAL INFO FROM ACN 375196: I SAW THE B737 AND MENTIONED IT TO THE CAPT. IT WAS BELOW US ABOUT 400 FT AND APPROX 3/4 OF A MI TO OUR R. IT WAS NOT CONVERGING WITH US IN MY OPINION AT THE TIME OF THE WAVE-OFF. WE SUBSEQUENTLY WROTE THE ACFT UP FOR A POSSIBLE ILS PROB WITH OUR MAINT DEPT.

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.