Narrative:

Air carrier Z was a factor in this scenario; but I don't believe that separation was lost between that aircraft and either aircraft X or air carrier Y. Air carrier Z was approaching abe from the west to land at abe. Air carrier Z was descending to 6;000 feet east bound while aircraft X was northeast bound climbing to 5;000 feet. The speed of these two aircraft led me to believe that air carrier Z would overtake aircraft X and then be able to continue descending once aircraft X was overtaken. As aircraft X leveled off and the airspeed increased; I also observed that air carrier Z was slowing down. I called traffic to these aircraft; and upon observing the traffic air carrier Z was instructed to maintain visual separation with aircraft X and descend to 3;000 feet. Air carrier Z asked about the heading of aircraft X; and upon being told that he would continue northeast bound; said something about passing him to the south. While this was occurring air carrier Y was south of them north bound at 4;000 feet. This aircraft was going around some weather that I could not observe; and would continue north bound to the lvz VORTAC when able. I became concerned about air carrier Z descending to 3;000 feet in time to remain separated from air carrier Y. I climbed air carrier Y to 5;000 feet to help insure that these two aircraft remained separated; and this worked as planned. The problem was that aircraft X still remained north of air carrier Y at 5;000 feet; and now air carrier Y was also at 5;000 feet. I was not yet aware that these two would conflict; and I proceeded to point out the airport to the landing air carrier Z. Once air carrier Z was cleared for a visual approach and switched to the tower I went back to the other two aircraft. When I observed the approaching conflict between aircraft X and air carrier Y they were 3-4 miles apart and converging. I turned air carrier Y and called the traffic. I turned aircraft X also and called the traffic. Air carrier Y reported the traffic in sight and I instructed him to maintain visual separation. I told aircraft X about this instruction to air carrier Y. Unfortunately; I believe that these two aircraft were approximately two miles apart by the time that this was accomplished. Aircraft X was returned on course once the conflict was averted and neither pilot expressed any other concerns.my entire career I have heard that errors are very common at the beginning or at the end of a shift. This event occurred eleven minutes after the start of my shift. My first mistake was not vectoring air carrier Z away from aircraft X for his descent and the original separation. I knew that the overtake would need watching; but I chose to let the aircraft continue straight towards the airport. My second mistake was when I climbed air carrier Y to 5;000 feet. I was focused on him and air carrier Z at that point; and somehow just wasn't thinking about aircraft X at 5;000 feet. I did need air carrier Y at 5;000 or 7;000 feet prior to him leaving my airspace and I was probably thinking about this when I climbed the aircraft to insure separation with air carrier Z. The need to clear air carrier Z for an approach contributed to my inattention to the problem about to occur with the other two aircraft.

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Original NASA ASRS Text

Title: ABE Controller experienced a loss of separation event when corrective action involving two aircraft was too late to secure needed distance; the reporter noting the event occurred shortly after assuming the position.

Narrative: Air Carrier Z was a factor in this scenario; but I don't believe that separation was lost between that aircraft and either Aircraft X or Air Carrier Y. Air Carrier Z was approaching ABE from the west to land at ABE. Air Carrier Z was descending to 6;000 feet east bound while Aircraft X was northeast bound climbing to 5;000 feet. The speed of these two aircraft led me to believe that Air Carrier Z would overtake Aircraft X and then be able to continue descending once Aircraft X was overtaken. As Aircraft X leveled off and the airspeed increased; I also observed that Air Carrier Z was slowing down. I called traffic to these aircraft; and upon observing the traffic Air Carrier Z was instructed to maintain visual separation with Aircraft X and descend to 3;000 feet. Air Carrier Z asked about the heading of Aircraft X; and upon being told that he would continue northeast bound; said something about passing him to the south. While this was occurring Air Carrier Y was south of them north bound at 4;000 feet. This aircraft was going around some weather that I could not observe; and would continue north bound to the LVZ VORTAC when able. I became concerned about Air Carrier Z descending to 3;000 feet in time to remain separated from Air Carrier Y. I climbed Air Carrier Y to 5;000 feet to help insure that these two aircraft remained separated; and this worked as planned. The problem was that Aircraft X still remained north of Air Carrier Y at 5;000 feet; and now Air Carrier Y was also at 5;000 feet. I was not yet aware that these two would conflict; and I proceeded to point out the airport to the landing Air Carrier Z. Once Air Carrier Z was cleared for a visual approach and switched to the Tower I went back to the other two aircraft. When I observed the approaching conflict between Aircraft X and Air Carrier Y they were 3-4 miles apart and converging. I turned Air Carrier Y and called the traffic. I turned Aircraft X also and called the traffic. Air Carrier Y reported the traffic in sight and I instructed him to maintain visual separation. I told Aircraft X about this instruction to Air Carrier Y. Unfortunately; I believe that these two aircraft were approximately two miles apart by the time that this was accomplished. Aircraft X was returned on course once the conflict was averted and neither pilot expressed any other concerns.My entire career I have heard that errors are very common at the beginning or at the end of a shift. This event occurred eleven minutes after the start of my shift. My first mistake was not vectoring Air Carrier Z away from Aircraft X for his descent and the original separation. I knew that the overtake would need watching; but I chose to let the aircraft continue straight towards the airport. My second mistake was when I climbed Air Carrier Y to 5;000 feet. I was focused on him and Air Carrier Z at that point; and somehow just wasn't thinking about Aircraft X at 5;000 feet. I did need Air Carrier Y at 5;000 or 7;000 feet prior to him leaving my airspace and I was probably thinking about this when I climbed the aircraft to insure separation with Air Carrier Z. The need to clear Air Carrier Z for an approach contributed to my inattention to the problem about to occur with the other two aircraft.

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.