Narrative:

Facility was mid-way through a 48 hour eram test. Received position briefing and relieved radar position. Went to invoke 'pref-set' (preferential settings) for this sector and there were none. I had apparently overwritten sector X 'pref-set' the night before when using an atypical sector combination. I was using the previous controller's 'pref-set' until I could update my own with 21 plus aircraft under my control. Air carrier Y was in the middle of a 2 gate double arrival stream. Air carrier X was an overflight 'swimming upstream;' requested a descent clearance to FL310 from FL350. Several of the south stream aircraft had been descended to FL320 to clear traffic; now given FL300 for air carrier X new requested altitude. The plan was to wait for descent on air carrier Y until past air carrier X at FL350; then air carrier X requested lower. Air carrier Y needed descent due to proximity to arrival gate and air carrier X's lower altitude. Air carrier X was given a left turn 15 degrees for his descent and cleared to FL330 interim. Air carrier Y was descended to FL300 then given a gate crossing clearance of FL190. When air carrier X was established north of traffic; cleared to FL310; the radar associate updated air carrier X route. The route was close to air carrier Y; but appeared to clear; so air carrier X was cleared on course to preclude a further conflict with aircraft on either arrival stream. Air carrier X passed air carrier Y; both aircraft descending and appeared to clear with minimum separation of 5 NM. Recommendation; take more time to establish that correct eram 'pref-set' is available. Using another controller's 'pref-set' is definitely a distraction and disadvantage. It would have been more prudent to clear air carrier x on course 'reaching FL310'; giving more time and altitude margin to ensure separation.

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Original NASA ASRS Text

Title: Enroute Controller described a probable loss of separation event during a ERAM testing period; the Controller listed the lack of Preferential Settings ('pref-set') availability as one causal factor.

Narrative: Facility was mid-way through a 48 hour ERAM test. Received position briefing and relieved RADAR position. Went to invoke 'pref-set' (Preferential Settings) for this sector and there were none. I had apparently overwritten Sector X 'pref-set' the night before when using an atypical sector combination. I was using the previous Controller's 'pref-set' until I could update my own with 21 plus aircraft under my control. Air Carrier Y was in the middle of a 2 gate double arrival stream. Air Carrier X was an overflight 'swimming upstream;' requested a descent clearance to FL310 from FL350. Several of the south stream aircraft had been descended to FL320 to clear traffic; now given FL300 for Air Carrier X new requested altitude. The plan was to wait for descent on Air Carrier Y until past Air Carrier X at FL350; then Air Carrier X requested lower. Air Carrier Y needed descent due to proximity to arrival gate and Air Carrier X's lower altitude. Air Carrier X was given a left turn 15 degrees for his descent and cleared to FL330 interim. Air Carrier Y was descended to FL300 then given a gate crossing clearance of FL190. When Air Carrier X was established north of traffic; cleared to FL310; the RADAR Associate updated Air Carrier X route. The route was close to Air Carrier Y; but appeared to clear; so Air Carrier X was cleared on course to preclude a further conflict with aircraft on either arrival stream. Air Carrier X passed Air Carrier Y; both aircraft descending and appeared to clear with minimum separation of 5 NM. Recommendation; take more time to establish that correct ERAM 'pref-set' is available. Using another Controller's 'pref-set' is definitely a distraction and disadvantage. It would have been more prudent to clear Air Carrier x on course 'reaching FL310'; giving more time and altitude margin to ensure separation.

Data retrieved from NASA's ASRS site as of July 2013 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.