Narrative:

Working arrival, final controller. Traffic very heavy. Terminated a practice approach due to traffic. He requested clearance to hou. No time to find clearance. Turned sbound (180) off localizer and climbed to 5000. Handoff taken on air carrier X, on downwind south of localizer heading 310, level 5000 ft. Air carrier Y, B737, departed aus heading 230 degrees climbing to 4000. Air carrier Y turned heading 270. Air carrier X descended to 3000 for traffic at 5000 that was turned off localizer (air carrier on different frequency and scope) conflict alert sounded. Paths had crossed. Air carrier Y received TCASII RA and descended. Complained of traffic descending into him. Separation was not lost but it was more by luck than planning. Series of events, beginning with turning the practice approach off the localizer. Supplemental information from acn 263160: the A45 IFR clearance was 'turn right heading 230 within 2 mi maintenance 4000 ft. Shortly after takeoff aus tower switched flight to aus departure control where we were given radar contact and told to maintain 4000 ft. Leaving about 3200 ft our TCASII gave us a yellow traffic advisory on traffic at 5000 ft. (I was climbing at about 500 FPM.) upon reaching 4000 ft our TCASII gave us a red RA to descend now. I pushed the nose of the aircraft over and desnding to about 3500 ft. A advised the departure controller that I was descending to a lower altitude because of traffic that was descending on top of us. I now observed a target on our TCASII that had descended from 5000 ft to about 4500 ft. I asked the controller if he was working or talking to the traffic. He replied that the metroliner was on another frequency and he was not talking to that traffic. As I left my assigned altitude of 4000 ft for lower I glanced over my left shoulder and saw a red and white twin engine aircraft descending toward my aircraft in my 8-9 O'clock position and 1/2 mi. Shortly after descending to 3500 ft the departure controller now reclred us to 10000 ft. Our flight then proceeded onto denver.

Related reports:

Google
 

Original NASA ASRS Text

Title: ACR X DSCNT THROUGH OCCUPIED ALT FROM ACR Y TCASII TA RA EVASIVE ACTION TAKEN DSND.

Narrative: WORKING ARR, FINAL CTLR. TFC VERY HVY. TERMINATED A PRACTICE APCH DUE TO TFC. HE REQUESTED CLRNC TO HOU. NO TIME TO FIND CLRNC. TURNED SBOUND (180) OFF LOC AND CLBED TO 5000. HDOF TAKEN ON ACR X, ON DOWNWIND S OF LOC HDG 310, LEVEL 5000 FT. ACR Y, B737, DEPARTED AUS HDG 230 DEGS CLBING TO 4000. ACR Y TURNED HDG 270. ACR X DSNDED TO 3000 FOR TFC AT 5000 THAT WAS TURNED OFF LOC (ACR ON DIFFERENT FREQ AND SCOPE) CONFLICT ALERT SOUNDED. PATHS HAD CROSSED. ACR Y RECEIVED TCASII RA AND DSNDED. COMPLAINED OF TFC DSNDING INTO HIM. SEPARATION WAS NOT LOST BUT IT WAS MORE BY LUCK THAN PLANNING. SERIES OF EVENTS, BEGINNING WITH TURNING THE PRACTICE APCH OFF THE LOC. SUPPLEMENTAL INFO FROM ACN 263160: THE A45 IFR CLRNC WAS 'TURN R HDG 230 WITHIN 2 MI MAINT 4000 FT. SHORTLY AFTER TKOF AUS TWR SWITCHED FLT TO AUS DEP CTL WHERE WE WERE GIVEN RADAR CONTACT AND TOLD TO MAINTAIN 4000 FT. LEAVING ABOUT 3200 FT OUR TCASII GAVE US A YELLOW TFC ADVISORY ON TFC AT 5000 FT. (I WAS CLBING AT ABOUT 500 FPM.) UPON REACHING 4000 FT OUR TCASII GAVE US A RED RA TO DSND NOW. I PUSHED THE NOSE OF THE ACFT OVER AND DESNDING TO ABOUT 3500 FT. A ADVISED THE DEP CTLR THAT I WAS DSNDING TO A LOWER ALT BECAUSE OF TFC THAT WAS DSNDING ON TOP OF US. I NOW OBSERVED A TARGET ON OUR TCASII THAT HAD DSNDED FROM 5000 FT TO ABOUT 4500 FT. I ASKED THE CTLR IF HE WAS WORKING OR TALKING TO THE TFC. HE REPLIED THAT THE METROLINER WAS ON ANOTHER FREQ AND HE WAS NOT TALKING TO THAT TFC. AS I LEFT MY ASSIGNED ALT OF 4000 FT FOR LOWER I GLANCED OVER MY L SHOULDER AND SAW A RED AND WHITE TWIN ENG ACFT DSNDING TOWARD MY ACFT IN MY 8-9 O'CLOCK POS AND 1/2 MI. SHORTLY AFTER DSNDING TO 3500 FT THE DEP CTLR NOW RECLRED US TO 10000 FT. OUR FLT THEN PROCEEDED ONTO DENVER.

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.