Narrative:

I was working final monitor west at mem; I did the frequency over ride check. I notified local that final monitoring was in progress and determined how far out traffic was visible. Local said 2 - 2 1/2 mi. Local asked about calling the approach fixes because the DME on the runway 36L localizer was OTS. Final monitor east commented that the WX sequence on the ids screen was not current. He/she moved down to the next position (about 3 ft) to check the current WX and I monitored the ATIS; to determine the current WX and to verify that the DME OTS was broadcast correctly. Aircraft X was established on the runway 36L localizer crossing the step-down fix at 4000 ft while aircraft Y was on the base for the east parallel about 2 mi behind aircraft X at 3000 ft. All is well. I move on with my scan. A few seconds later; fme points to aircraft X and tells me to stop them at 4000 ft. I look at aircraft X and he is descending out of 3700 ft still on the localizer and aircraft Y is about 2 mi behind on a northeast heading. Aircraft Y apparently went through the localizer and was correcting. I told fme that they had diverging courses. Procedures require that aircraft are established on the final and on tower frequency outside of the west step-down fix; west runway at 4000 ft; east runway at 3000 ft. Aircraft Y went through the localizer and joined 2 mi inside the east step-down fix. The east step-down fix is approximately 1 mi inside the west step-down fix. I don't see how I could have prevented this error and I certainly did nothing to cause it.

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Original NASA ASRS Text

Title: MEM APCH CTLR DESCRIBED CONFLICT WHILE WORKING FINAL MONITOR POS WHEN ACFT MISSED LOC INTERCEPT AND CONFLICTED WITH PARALLEL TFC.

Narrative: I WAS WORKING FINAL MONITOR W AT MEM; I DID THE FREQ OVER RIDE CHK. I NOTIFIED LCL THAT FINAL MONITORING WAS IN PROGRESS AND DETERMINED HOW FAR OUT TFC WAS VISIBLE. LCL SAID 2 - 2 1/2 MI. LCL ASKED ABOUT CALLING THE APCH FIXES BECAUSE THE DME ON THE RWY 36L LOC WAS OTS. FINAL MONITOR E COMMENTED THAT THE WX SEQUENCE ON THE IDS SCREEN WAS NOT CURRENT. HE/SHE MOVED DOWN TO THE NEXT POS (ABOUT 3 FT) TO CHK THE CURRENT WX AND I MONITORED THE ATIS; TO DETERMINE THE CURRENT WX AND TO VERIFY THAT THE DME OTS WAS BROADCAST CORRECTLY. ACFT X WAS ESTABLISHED ON THE RWY 36L LOC XING THE STEP-DOWN FIX AT 4000 FT WHILE ACFT Y WAS ON THE BASE FOR THE E PARALLEL ABOUT 2 MI BEHIND ACFT X AT 3000 FT. ALL IS WELL. I MOVE ON WITH MY SCAN. A FEW SECONDS LATER; FME POINTS TO ACFT X AND TELLS ME TO STOP THEM AT 4000 FT. I LOOK AT ACFT X AND HE IS DSNDING OUT OF 3700 FT STILL ON THE LOC AND ACFT Y IS ABOUT 2 MI BEHIND ON A NE HDG. ACFT Y APPARENTLY WENT THROUGH THE LOC AND WAS CORRECTING. I TOLD FME THAT THEY HAD DIVERGING COURSES. PROCS REQUIRE THAT ACFT ARE ESTABLISHED ON THE FINAL AND ON TWR FREQ OUTSIDE OF THE W STEP-DOWN FIX; W RWY AT 4000 FT; E RWY AT 3000 FT. ACFT Y WENT THROUGH THE LOC AND JOINED 2 MI INSIDE THE E STEP-DOWN FIX. THE E STEP-DOWN FIX IS APPROX 1 MI INSIDE THE W STEP-DOWN FIX. I DON'T SEE HOW I COULD HAVE PREVENTED THIS ERROR AND I CERTAINLY DID NOTHING TO CAUSE IT.

Data retrieved from NASA's ASRS site as of January 2009 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.