Narrative:

An large transport was southbound at FL280 requesting FL310. Large transport Y was northbound at FL290. (Both were large transport's.) sector was extremely busy with 22 aircraft. This sector is of a size that requires it to be worked on a 125 mi range. On that range with 22 full data blocks the congestion is considerable and data blocks overlap. Additionally the sector underlies a super high sector and only contains 9000' of vertical airspace. Due to short staffing I had been working a combined radar and handoff position with heavy traffic for 1 1/2 hours. Large transport Y's full data block was obscured by several others and I didn't see him when I climbed large transport X to FL310. The situation was discovered through the conflict alert at which time I turned both aircraft and descended large transport Y. This sector suffers from a chronic overload problem because the super-high was established to take approximately half the traffic but departures from the washington metropolitan area who are requesting altitudes in the super-high structure are routinely stopped at lower altitudes due to traffic volume in the sector which lies geographically north of this sector. When the traffic counts were done to validate the high (ilm) and super-high (diw) sectors those aircraft requesting at or above FL350 were included in the super-high structure which evenly divided the traffic between the two sectors. Since many of these aircraft requesting higher altitudes are being stopped lower the high (ilm) sector becomes oversaturated causing an imbalance in the traffic worked by each sector. This was a primary cause of this incident.

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Original NASA ASRS Text

Title: AN LGT SOUTHBOUND REQUESTED A HIGHER ALT AND THE ARTCC RADAR CTLR APPROVED THE REQUEST WHICH RESULTED IN LESS THAN STANDARD SEPARATION FROM A NORTHBOUND LGT.

Narrative: AN LGT WAS SBND AT FL280 REQUESTING FL310. LGT Y WAS NBOUND AT FL290. (BOTH WERE LGT'S.) SECTOR WAS EXTREMELY BUSY WITH 22 ACFT. THIS SECTOR IS OF A SIZE THAT REQUIRES IT TO BE WORKED ON A 125 MI RANGE. ON THAT RANGE WITH 22 FULL DATA BLOCKS THE CONGESTION IS CONSIDERABLE AND DATA BLOCKS OVERLAP. ADDITIONALLY THE SECTOR UNDERLIES A SUPER HIGH SECTOR AND ONLY CONTAINS 9000' OF VERTICAL AIRSPACE. DUE TO SHORT STAFFING I HAD BEEN WORKING A COMBINED RADAR AND HANDOFF POSITION WITH HEAVY TFC FOR 1 1/2 HRS. LGT Y'S FULL DATA BLOCK WAS OBSCURED BY SEVERAL OTHERS AND I DIDN'T SEE HIM WHEN I CLIMBED LGT X TO FL310. THE SITUATION WAS DISCOVERED THROUGH THE CONFLICT ALERT AT WHICH TIME I TURNED BOTH ACFT AND DESCENDED LGT Y. THIS SECTOR SUFFERS FROM A CHRONIC OVERLOAD PROBLEM BECAUSE THE SUPER-HIGH WAS ESTABLISHED TO TAKE APPROX HALF THE TFC BUT DEPS FROM THE WASHINGTON METROPOLITAN AREA WHO ARE REQUESTING ALTS IN THE SUPER-HIGH STRUCTURE ARE ROUTINELY STOPPED AT LOWER ALTS DUE TO TFC VOLUME IN THE SECTOR WHICH LIES GEOGRAPHICALLY N OF THIS SECTOR. WHEN THE TFC COUNTS WERE DONE TO VALIDATE THE HIGH (ILM) AND SUPER-HIGH (DIW) SECTORS THOSE ACFT REQUESTING AT OR ABOVE FL350 WERE INCLUDED IN THE SUPER-HIGH STRUCTURE WHICH EVENLY DIVIDED THE TFC BETWEEN THE TWO SECTORS. SINCE MANY OF THESE ACFT REQUESTING HIGHER ALTS ARE BEING STOPPED LOWER THE HIGH (ILM) SECTOR BECOMES OVERSATURATED CAUSING AN IMBALANCE IN THE TFC WORKED BY EACH SECTOR. THIS WAS A PRIMARY CAUSE OF THIS INCIDENT.

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.