Narrative:

I am a recently certified fpl at a level 3 approach control. I was working approach and departure combined. Traffic was light. The 3 aircraft involved were aircraft a: scheduled air carrier (jet), aircraft B: scheduled air carrier (jet), and aircraft C: small transport. WX was MVFR. Aircraft a and B were on downwinds east and west of localizer for same runway. ILS approach to same runway. Aircraft C was on left base for an intersecting runway ILS approach. WX became IFR. I relayed WX and received acknowledgement from each. I issued aircraft B a left turn heading 310 degrees and descent to 3000'. I issued aircraft C a left turn heading 310 degrees to join localizer and descent to 2100', #1 for airport. Aircraft a was sequenced to follow aircraft C, and aircraft B to follow aircraft a. Aircraft a was turned right to 140 and 160 degrees, and descended to 2500'. Aircraft C was turned left to 280 degrees. Aircraft a was closing too rapidly on aircraft C to provide sep on simultaneous ILS approachs to intersecting runways, so instead of allowing aircraft a to go through localizer toward aircraft, I turned him back to a downwind toward aircraft C. I turned aircraft C left heading 250 degrees to join and descended to 2500', climbed aircraft a to 4000' due to proximity of aircraft B. Pilot acknowledged with 'out of 3 for 4.' turned aircraft C immediately left heading 150 degrees and told aircraft a to expedite through 5000'. Aircraft acknowledged he had traffic and was 'out of 3 for 5.' tried to use visibility sep between aircraft, but pilot was going into clouds. Turned aircraft C left heading 130 degrees to diverge courses. My own inexperience caused this operational error. I will never forget this lesson to be learned. Aircraft a should have gone through final to follow aircraft B. Supplemental information from acn 109141: it appeared the controller made a mistake and had 2 aircraft in the same airspace at the same altitude.

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Original NASA ASRS Text

Title: IN ATTEMPTING TO SEQUENCE ARR TRAFFIC, CTLR VECTORED ACFT TOO CLOSE TO ANOTHER ACFT. LESS THAN STANDARD SEPARATION OCCURRED.

Narrative: I AM A RECENTLY CERTIFIED FPL AT A LEVEL 3 APCH CTL. I WAS WORKING APCH AND DEP COMBINED. TFC WAS LIGHT. THE 3 ACFT INVOLVED WERE ACFT A: SCHEDULED ACR (JET), ACFT B: SCHEDULED ACR (JET), AND ACFT C: SMT. WX WAS MVFR. ACFT A AND B WERE ON DOWNWINDS E AND W OF LOC FOR SAME RWY. ILS APCH TO SAME RWY. ACFT C WAS ON LEFT BASE FOR AN INTERSECTING RWY ILS APCH. WX BECAME IFR. I RELAYED WX AND RECEIVED ACKNOWLEDGEMENT FROM EACH. I ISSUED ACFT B A LEFT TURN HDG 310 DEGS AND DSCNT TO 3000'. I ISSUED ACFT C A LEFT TURN HDG 310 DEGS TO JOIN LOC AND DSCNT TO 2100', #1 FOR ARPT. ACFT A WAS SEQUENCED TO FOLLOW ACFT C, AND ACFT B TO FOLLOW ACFT A. ACFT A WAS TURNED RIGHT TO 140 AND 160 DEGS, AND DSNDED TO 2500'. ACFT C WAS TURNED LEFT TO 280 DEGS. ACFT A WAS CLOSING TOO RAPIDLY ON ACFT C TO PROVIDE SEP ON SIMULTANEOUS ILS APCHS TO INTERSECTING RWYS, SO INSTEAD OF ALLOWING ACFT A TO GO THROUGH LOC TOWARD ACFT, I TURNED HIM BACK TO A DOWNWIND TOWARD ACFT C. I TURNED ACFT C LEFT HDG 250 DEGS TO JOIN AND DSNDED TO 2500', CLBED ACFT A TO 4000' DUE TO PROX OF ACFT B. PLT ACKNOWLEDGED WITH 'OUT OF 3 FOR 4.' TURNED ACFT C IMMEDIATELY LEFT HDG 150 DEGS AND TOLD ACFT A TO EXPEDITE THROUGH 5000'. ACFT ACKNOWLEDGED HE HAD TFC AND WAS 'OUT OF 3 FOR 5.' TRIED TO USE VIS SEP BTWN ACFT, BUT PLT WAS GOING INTO CLOUDS. TURNED ACFT C LEFT HDG 130 DEGS TO DIVERGE COURSES. MY OWN INEXPERIENCE CAUSED THIS OPERROR. I WILL NEVER FORGET THIS LESSON TO BE LEARNED. ACFT A SHOULD HAVE GONE THROUGH FINAL TO FOLLOW ACFT B. SUPPLEMENTAL INFO FROM ACN 109141: IT APPEARED THE CTLR MADE A MISTAKE AND HAD 2 ACFT IN THE SAME AIRSPACE AT THE SAME ALT.

Data retrieved from NASA's ASRS site as of August 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.