Narrative:

A MD11 was inbound to koa from drayk intersection. A B757 was outbound from ogg to eloyi (outer fix of our airspace). The B757 had leveled off at FL380 and the MD11 was preceding direct upp VORTAC; initially when I looked at their flight paths it did not appear to be a problem. This crossing traffic is usually always present in my mind and if it is a; I resolve it immediately instead of waiting. Because I did not think they would be a factor; I chose to leave the MD11 at his present altitude. After a few minutes I scanned my scope and since I was using two scopes; I had to look at each individually; I noticed nothing on the first; but on the second I saw 3 data blocks overlapping; and two targets converging. I went back and moved the data tags and immediately notice what had happened. I issue a turn to both aircraft and descend the MD11 to avoid any conflict. The B757 said he had an RA advisory and climbed up 200 ft but said my turn would be sufficient to keep clear so he went back down to FL380. No conflict alert ever went off. I am not sure of the separation between the two aircraft; as my range was set to about 300 miles to be able to see all of my airspace; but I believe there was at least 5 miles. I reported the incident to my supervisor because of the RA advisory the B757 gave me; even though he did not complete it. This was a mistake in judgment on my part. I should never have assumed the speeds/flight paths would take the aircraft where they originally appeared to be going. I will be more vigilant in the future in preventing incidents like this as safety is always my first priority.

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Original NASA ASRS Text

Title: HCF Controller described a possible loss of separation event during combined position operations; with expanded range settings; the Controller acknowledging a lack of vigilance.

Narrative: A MD11 was inbound to KOA from DRAYK Intersection. A B757 was outbound from OGG to ELOYI (outer fix of our airspace). The B757 had leveled off at FL380 and the MD11 was preceding direct UPP VORTAC; initially when I looked at their flight paths it did not appear to be a problem. This crossing traffic is usually always present in my mind and if it is a; I resolve it immediately instead of waiting. Because I did not think they would be a factor; I chose to leave the MD11 at his present altitude. After a few minutes I scanned my scope and since I was using two scopes; I had to look at each individually; I noticed nothing on the first; but on the second I saw 3 Data Blocks overlapping; and two targets converging. I went back and moved the Data Tags and immediately notice what had happened. I issue a turn to both aircraft and descend the MD11 to avoid any conflict. The B757 said he had an RA advisory and climbed up 200 FT but said my turn would be sufficient to keep clear so he went back down to FL380. No Conflict Alert ever went off. I am not sure of the separation between the two aircraft; as my range was set to about 300 miles to be able to see all of my airspace; but I believe there was at least 5 miles. I reported the incident to my supervisor because of the RA advisory the B757 gave me; even though he did not complete it. This was a mistake in judgment on my part. I should never have assumed the speeds/flight paths would take the aircraft where they originally appeared to be going. I will be more vigilant in the future in preventing incidents like this as safety is always my first priority.

Data retrieved from NASA's ASRS site as of April 2012 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.