Narrative:

I was providing OJT on radar east low, which was combined with radar east high and east coordinator. Barksdale AFB was conducting a training exercise comprised of a 16 aircraft (B52's) departure. The departure interval was supposed to be 1 min in trail. All 16 aircraft had abcd as a call sign prefix, followed by 2 digits. The briefed departure interval was key in my decision to not have the coordinator position split off. Similar call signs for the B52's was detrimental to good hearback/readback. The operational error occurred when aircraft Y was issued a descent clearance from 13000 ft to 5000 ft with opposite direction traffic abcd 12(B52) leveling at 12000 ft, approximately 12 mi apart with a 700 KT closure rate. At the time the developmental issued the descent clearance, I was coordinating a release clearance for an IFR departure off of a satellite airport, with radar flight data. I noticed the conflict and issued traffic alerts to both aircraft when they were approximately 6.5 mi apart. Poor radio quality, numerous hearback/readback errors, departure intervals not always 1 min in trail, B52 not willing to accept vectors off of runway heading for between 10-15 mi, were all ingredients that factored into the difficulty level. I believe that if the coordinator position had been open, I would have noticed the judgemental error of descending the MU30 immediately, and taken action to prevent the error.

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Original NASA ASRS Text

Title: OPERROR OCCURRED WHEN INSTRUCTOR CTLR BECOMES INVOLVED WITH RELEASING TFC OFF A SATELLITE ARPT WHILE THE DEVELOPMENTAL CTLR ISSUES A DSCNT CLRNC TO AN MU2 THROUGH AN OCCUPIED ALT.

Narrative: I WAS PROVIDING OJT ON RADAR E LOW, WHICH WAS COMBINED WITH RADAR E HIGH AND E COORDINATOR. BARKSDALE AFB WAS CONDUCTING A TRAINING EXERCISE COMPRISED OF A 16 ACFT (B52'S) DEP. THE DEP INTERVAL WAS SUPPOSED TO BE 1 MIN IN TRAIL. ALL 16 ACFT HAD ABCD AS A CALL SIGN PREFIX, FOLLOWED BY 2 DIGITS. THE BRIEFED DEP INTERVAL WAS KEY IN MY DECISION TO NOT HAVE THE COORDINATOR POS SPLIT OFF. SIMILAR CALL SIGNS FOR THE B52'S WAS DETRIMENTAL TO GOOD HEARBACK/READBACK. THE OPERROR OCCURRED WHEN ACFT Y WAS ISSUED A DSCNT CLRNC FROM 13000 FT TO 5000 FT WITH OPPOSITE DIRECTION TFC ABCD 12(B52) LEVELING AT 12000 FT, APPROX 12 MI APART WITH A 700 KT CLOSURE RATE. AT THE TIME THE DEVELOPMENTAL ISSUED THE DSCNT CLRNC, I WAS COORDINATING A RELEASE CLRNC FOR AN IFR DEP OFF OF A SATELLITE ARPT, WITH RADAR FLT DATA. I NOTICED THE CONFLICT AND ISSUED TFC ALERTS TO BOTH ACFT WHEN THEY WERE APPROX 6.5 MI APART. POOR RADIO QUALITY, NUMEROUS HEARBACK/READBACK ERRORS, DEP INTERVALS NOT ALWAYS 1 MIN IN TRAIL, B52 NOT WILLING TO ACCEPT VECTORS OFF OF RWY HDG FOR BTWN 10-15 MI, WERE ALL INGREDIENTS THAT FACTORED INTO THE DIFFICULTY LEVEL. I BELIEVE THAT IF THE COORDINATOR POS HAD BEEN OPEN, I WOULD HAVE NOTICED THE JUDGEMENTAL ERROR OF DSNDING THE MU30 IMMEDIATELY, AND TAKEN ACTION TO PREVENT THE ERROR.

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.