Narrative:

I was working arrival radar west, combined with departure radar west and a shared final radar. I had aircraft on 2 separate frequencys. Small transport X, reported to me at 4000', 3 mi south of bna airport, IFR en route to jwn airport (10 mi west of bna) on a 290 degree heading. Shortly thereafter, air carrier Y departed bna heading 280 degree and climbing to 4000'. Due to split frequencys, I did not hear air carrier Y on initial call, but instead heard another air carrier inbound to bna report the airport in sight. I proceeded to clear other air carrier for a visual approach to runway 2L at bna. I then made 2 other xmissions to other aircraft before air carrier Y reattempted contact. I immediately became aware of the problem with small transport X which had been cleared for a visual approach to jwn. I issued traffic then turned air carrier Y away from small transport X. It appears the aircraft passed 1 1/2 mi laterally and 600' vertically prior to divergence being established. During the time leading to and during the incident, I had 2 jets on the approach to bna, 3 other departures, and the small transport X en route to jwn. I should have waited until the small transport X was no factor to the departure release area prior to issuing approach clearance. Also, it happened 3 other times during this 5-7 min period that aircraft called on both frequencys at once, causing garbled communications. Callback conversation with reporter revealed the following: reporter stated bna ATC tower has a departure route in which they can release aircraft without coordination. The reporter failed to hold departures off bna prior to clearing small transport X into the airspace. Working combined position with several frequencys in use was discussed with the reporter. This policy is being modified. Air carrier Y was an small transport.

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Original NASA ASRS Text

Title: RADAR CTLR HAD LESS THAN STANDARD SEPARATION BETWEEN SMT X AND ACR Y. SYSTEM ERROR.

Narrative: I WAS WORKING ARR RADAR W, COMBINED WITH DEP RADAR W AND A SHARED FINAL RADAR. I HAD ACFT ON 2 SEPARATE FREQS. SMT X, REPORTED TO ME AT 4000', 3 MI S OF BNA ARPT, IFR ENRTE TO JWN ARPT (10 MI W OF BNA) ON A 290 DEG HDG. SHORTLY THEREAFTER, ACR Y DEPARTED BNA HDG 280 DEG AND CLIMBING TO 4000'. DUE TO SPLIT FREQS, I DID NOT HEAR ACR Y ON INITIAL CALL, BUT INSTEAD HEARD ANOTHER ACR INBND TO BNA REPORT THE ARPT IN SIGHT. I PROCEEDED TO CLEAR OTHER ACR FOR A VISUAL APCH TO RWY 2L AT BNA. I THEN MADE 2 OTHER XMISSIONS TO OTHER ACFT BEFORE ACR Y REATTEMPTED CONTACT. I IMMEDIATELY BECAME AWARE OF THE PROBLEM WITH SMT X WHICH HAD BEEN CLRED FOR A VISUAL APCH TO JWN. I ISSUED TFC THEN TURNED ACR Y AWAY FROM SMT X. IT APPEARS THE ACFT PASSED 1 1/2 MI LATERALLY AND 600' VERTICALLY PRIOR TO DIVERGENCE BEING ESTABLISHED. DURING THE TIME LEADING TO AND DURING THE INCIDENT, I HAD 2 JETS ON THE APCH TO BNA, 3 OTHER DEPS, AND THE SMT X ENRTE TO JWN. I SHOULD HAVE WAITED UNTIL THE SMT X WAS NO FACTOR TO THE DEP RELEASE AREA PRIOR TO ISSUING APCH CLRNC. ALSO, IT HAPPENED 3 OTHER TIMES DURING THIS 5-7 MIN PERIOD THAT ACFT CALLED ON BOTH FREQS AT ONCE, CAUSING GARBLED COMS. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: REPORTER STATED BNA ATC TWR HAS A DEP ROUTE IN WHICH THEY CAN RELEASE ACFT WITHOUT COORD. THE REPORTER FAILED TO HOLD DEPS OFF BNA PRIOR TO CLEARING SMT X INTO THE AIRSPACE. WORKING COMBINED POSITION WITH SEVERAL FREQS IN USE WAS DISCUSSED WITH THE REPORTER. THIS POLICY IS BEING MODIFIED. ACR Y WAS AN SMT.

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.