AUS Controller described witnessing a conflict event involving the use of visual separation between two aircraft; another controller working the aircraft providing another perspective.
Synopsis
AUS Controller described witnessing a conflict event involving the use of visual separation between two aircraft; another controller working the aircraft providing another perspective.
Narrative
I witnessed a Near Mid-Air Collision (NMAC) within the first four hours of my shift. All sectors were open. OJTI was taking place on RW. Air Carrier X departed AUS and was turned northeast; stopped at 5;000. Aircraft Y was inbound from the northeast; descending to 6;000. The aircraft were wired for the same common point in the sky; but separated. The RE Controller issued traffic to Air Carrier X; and the Air Carrier X pilot reported the traffic in sight. The RE Controller then told Air Carrier X to maintain Visual Separation from that traffic (Aircraft Y); and issued a climb to 12;000. I did not hear if Aircraft Y was informed that visual separation was being applied. The RE Controller then said; 'Oh; I've never had that happen before'; and the RE Controller then turned Aircraft Y left to a heading of 110; and turned Air Carrier X left to a heading of 010. The RE Controller then said that Air Carrier X had lost sight of his traffic; but the aircraft were already less than 1;000 FT and 3 miles. These two aircraft passed within 1 mile of each other at the same altitude on converging courses; a NMAC in my book. I've reported this before regarding the usage of visual separation at AUS. We use it incorrectly; inappropriately and we are going to kill someone. How close is too close? I thought that we were Controllers; but apparently we have a pattern and practice of asking the pilots to provide visual separation; and this is what happens. My recommendation? Why don't we just separate the aircraft?
Second reporter narrative
Aircraft Y southbound descending to 6;000. Air Carrier X northeast bound climbing to 5;000. Traffic issued to Aircraft Y; pilot advised we think we have him in sight. Aircraft Y instructed to maintain visual separation as he climbs through your altitude. Aircraft Y complies. Air Carrier X advised about the visual separation and instructed to climb to 120. Aircraft Y advises 'we've lost him'. Right a way I turned Aircraft Y east (110 heading) and Air Carrier X north (010 heading). Closest proximity was about 1.5 mi with Aircraft Y at 6;300; and Air Carrier X at 6;000 when they passed. No report of TCAS RA by either pilot. If pilot cannot maintain visual separation from another aircraft; they need to say so.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.