Narrative:

2/C130 ILS runway 16 approach at dyess AFB. I assumed to be a full stop. Dyess (dys) tower coordinated that both aircraft were requesting practice approachs as individual aircraft (aircraft X and aircraft Y). Dys tower coordinated that one of the aircraft would be on a 180 degree heading (I don't recall which). Normal procedure is that the first aircraft on 180 degrees, and second runway heading. The aircraft departed and there was a delay before the aircraft tagged properly. Aircraft Y called, I assumed on a 180 degree (first) aircraft. I instructed the pilot to turn right heading 270 degrees and maintain 4000 ft. Aircraft X called and had not tagged yet. Aircraft Y had tagged up and appeared to be turning west. (Aircraft Y tagged as aircraft X.) I reissued aircraft Y the correct code. Aircraft Y advised me that he was climbing to avoid the other C130 on a collision course. The aircraft passed over the other. I am unsure of the altitude, loss of vertical separation, lateral separation and a loss of divergence. I instructed aircraft Y to maintain 5000 ft. All other xmissions with aircraft Y were normal. Aircraft X finally tagged up 8 mi south. I had to instruct aircraft Y to turn north twice. I had to change the transponder code for aircraft Y. Aircraft X also took this code. Contributing factors: training pilots, 3 call signs, 3 transponder codes, 2 aircraft. Training controller. Dyess tower. Low experience level dys tower. Assumptions on my part. Poor radar quality and persecution (ongoing problem). (All the above was reported to the supervisor.)

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Original NASA ASRS Text

Title: ABI TRACON CTLR EXPERIENCED LOSS OF SEPARATION DURING C130 FLT BREAK-UP ATTEMPT.

Narrative: 2/C130 ILS RWY 16 APCH AT DYESS AFB. I ASSUMED TO BE A FULL STOP. DYESS (DYS) TWR COORDINATED THAT BOTH ACFT WERE REQUESTING PRACTICE APCHS AS INDIVIDUAL ACFT (ACFT X AND ACFT Y). DYS TWR COORDINATED THAT ONE OF THE ACFT WOULD BE ON A 180 DEG HDG (I DON'T RECALL WHICH). NORMAL PROC IS THAT THE FIRST ACFT ON 180 DEGS, AND SECOND RWY HDG. THE ACFT DEPARTED AND THERE WAS A DELAY BEFORE THE ACFT TAGGED PROPERLY. ACFT Y CALLED, I ASSUMED ON A 180 DEG (FIRST) ACFT. I INSTRUCTED THE PLT TO TURN R HDG 270 DEGS AND MAINTAIN 4000 FT. ACFT X CALLED AND HAD NOT TAGGED YET. ACFT Y HAD TAGGED UP AND APPEARED TO BE TURNING W. (ACFT Y TAGGED AS ACFT X.) I REISSUED ACFT Y THE CORRECT CODE. ACFT Y ADVISED ME THAT HE WAS CLBING TO AVOID THE OTHER C130 ON A COLLISION COURSE. THE ACFT PASSED OVER THE OTHER. I AM UNSURE OF THE ALT, LOSS OF VERT SEPARATION, LATERAL SEPARATION AND A LOSS OF DIVERGENCE. I INSTRUCTED ACFT Y TO MAINTAIN 5000 FT. ALL OTHER XMISSIONS WITH ACFT Y WERE NORMAL. ACFT X FINALLY TAGGED UP 8 MI S. I HAD TO INSTRUCT ACFT Y TO TURN N TWICE. I HAD TO CHANGE THE XPONDER CODE FOR ACFT Y. ACFT X ALSO TOOK THIS CODE. CONTRIBUTING FACTORS: TRAINING PLTS, 3 CALL SIGNS, 3 XPONDER CODES, 2 ACFT. TRAINING CTLR. DYESS TWR. LOW EXPERIENCE LEVEL DYS TWR. ASSUMPTIONS ON MY PART. POOR RADAR QUALITY AND PERSECUTION (ONGOING PROB). (ALL THE ABOVE WAS RPTED TO THE SUPVR.)

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.