Narrative:

Aircraft #1 departed lws northbound and cleared via airway climbing to the MEA of 6000 ft. Aircraft #2 was inbound from the north and level at 7000 ft. Aircraft #1 reported aircraft #2 in sight during departure climb out. Immediately after, aircraft #2 reported aircraft #1 in sight along with the airport in sight. Aircraft #2 was cleared for visual approach with restr to maintain visual separation from aircraft #1. Aircraft #1 was advised aircraft #2 was on visual approach and maintaining visual separation. Aircraft #1 advised they still had aircraft #2 in sight. When both aircraft were within 2 mi of each other, a voice on frequency said something to the effect of 'what are you guys doing?' a second voice said something like 'we're going around you, what are you worried about?' a few seconds later, aircraft #1 advised 'responding to RA.' it appeared both aircraft moved horizontally and aircraft #1 descended to near 5000 ft. The minimum IFR altitude I could assign in this area is also 5000 ft. There were 2-3 other aircraft on frequency. I have a few concerns with this incident. When I clear an aircraft to maintain visual separation, how that aircraft plans to provide visual separation is unknown. Will they turn left, right, climb, descend, or level off? The other aircraft and myself are left guessing. Second, when aircraft #2 states 'responding to RA,' I am also uninformed whether they will climb or descend. Even if aircraft #2 states they are descending, the questions begs, 'how far will this aircraft descend?' terrain and/or my minimum IFR altitude could have been a factor in the events that transpired in seconds. My not applying visual separation and keeping both aircraft vertically separated until clear could have resolved the situation. However, this would have caused delay to the arriving flight by keeping them high until very near the landing airport. Communication by the arriving aircraft of how it planned to apply visual separation would have been useful to the other pilot and myself. Instead, it became last second xmissions and actions. The extreme stress I endured during this incident could have only been exceeded by the 2 crews.

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Original NASA ASRS Text

Title: 2 DH8 ACFT APPLYING VISUAL SEPARATION DURING CLB AND DSCNT MANEUVER RESULT IN TCASII WHILE UNDER ZSE CTL.

Narrative: ACFT #1 DEPARTED LWS NBOUND AND CLRED VIA AIRWAY CLBING TO THE MEA OF 6000 FT. ACFT #2 WAS INBOUND FROM THE N AND LEVEL AT 7000 FT. ACFT #1 RPTED ACFT #2 IN SIGHT DURING DEP CLBOUT. IMMEDIATELY AFTER, ACFT #2 RPTED ACFT #1 IN SIGHT ALONG WITH THE ARPT IN SIGHT. ACFT #2 WAS CLRED FOR VISUAL APCH WITH RESTR TO MAINTAIN VISUAL SEPARATION FROM ACFT #1. ACFT #1 WAS ADVISED ACFT #2 WAS ON VISUAL APCH AND MAINTAINING VISUAL SEPARATION. ACFT #1 ADVISED THEY STILL HAD ACFT #2 IN SIGHT. WHEN BOTH ACFT WERE WITHIN 2 MI OF EACH OTHER, A VOICE ON FREQ SAID SOMETHING TO THE EFFECT OF 'WHAT ARE YOU GUYS DOING?' A SECOND VOICE SAID SOMETHING LIKE 'WE'RE GOING AROUND YOU, WHAT ARE YOU WORRIED ABOUT?' A FEW SECONDS LATER, ACFT #1 ADVISED 'RESPONDING TO RA.' IT APPEARED BOTH ACFT MOVED HORIZLY AND ACFT #1 DSNDED TO NEAR 5000 FT. THE MINIMUM IFR ALT I COULD ASSIGN IN THIS AREA IS ALSO 5000 FT. THERE WERE 2-3 OTHER ACFT ON FREQ. I HAVE A FEW CONCERNS WITH THIS INCIDENT. WHEN I CLR AN ACFT TO MAINTAIN VISUAL SEPARATION, HOW THAT ACFT PLANS TO PROVIDE VISUAL SEPARATION IS UNKNOWN. WILL THEY TURN L, R, CLB, DSND, OR LEVEL OFF? THE OTHER ACFT AND MYSELF ARE LEFT GUESSING. SECOND, WHEN ACFT #2 STATES 'RESPONDING TO RA,' I AM ALSO UNINFORMED WHETHER THEY WILL CLB OR DSND. EVEN IF ACFT #2 STATES THEY ARE DSNDING, THE QUESTIONS BEGS, 'HOW FAR WILL THIS ACFT DSND?' TERRAIN AND/OR MY MINIMUM IFR ALT COULD HAVE BEEN A FACTOR IN THE EVENTS THAT TRANSPIRED IN SECONDS. MY NOT APPLYING VISUAL SEPARATION AND KEEPING BOTH ACFT VERTLY SEPARATED UNTIL CLR COULD HAVE RESOLVED THE SIT. HOWEVER, THIS WOULD HAVE CAUSED DELAY TO THE ARRIVING FLT BY KEEPING THEM HIGH UNTIL VERY NEAR THE LNDG ARPT. COM BY THE ARRIVING ACFT OF HOW IT PLANNED TO APPLY VISUAL SEPARATION WOULD HAVE BEEN USEFUL TO THE OTHER PLT AND MYSELF. INSTEAD, IT BECAME LAST SECOND XMISSIONS AND ACTIONS. THE EXTREME STRESS I ENDURED DURING THIS INCIDENT COULD HAVE ONLY BEEN EXCEEDED BY THE 2 CREWS.

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.