Narrative:

A flight of two C130s; VFR pop-up; requested the high speed left downwind runway xx at ZZZ. About the time I was radar identifying the aircraft and coordinating with the tower for the request; I took a hand off on aircraft Y; IFR; inbound for landing at ZZZ. I had only been on position maybe 5 minutes or so. I vectored aircraft Y east southeast during the descent to make him #2. When I turned him in and cleared him for the visual approach runway xx; I advised him that he was following the C130s and I fully expected to have the required separation to touchdown when I frequency changed him to tower. Tower called not long afterward and coordinated a 360 for aircraft Y for spacing; which I approved. As I looked at the situation; I realized that the C130 flight had flown a wider pattern than I had expected and that aircraft Y had kept his speed up longer as well. I'm mostly certain that aircraft Y's altitude was well above the C130s; but I'm not 100% sure. It's been nagging at me; though; that I'm not sure whether I lost wake turbulence separation or not; which is why I am choosing to report it. I should have either had aircraft Y report the C130s in sight and instructed him to maintain visual separation or kept him wider longer before cutting him loose on the visual to ensure there was absolutely no way he could catch them. It was early in my shift and it was one of those days when I personally felt a little behind the eight ball before I even talked to any aircraft. I made the mistake of ignoring that personal indicator and not giving a little extra room as I normally would on those rare occasions I feel that way.

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Original NASA ASRS Text

Title: TRACON Controller described a flawed visual approach clearance resulting in an overtake situation; requiring a turn by the second aircraft on final; the reporter acknowledging the spacing judgment was inaccurate.

Narrative: A flight of two C130s; VFR pop-up; requested the high speed left downwind Runway XX at ZZZ. About the time I was RADAR identifying the aircraft and coordinating with the Tower for the request; I took a hand off on aircraft Y; IFR; inbound for landing at ZZZ. I had only been on position maybe 5 minutes or so. I vectored aircraft Y east southeast during the descent to make him #2. When I turned him in and cleared him for the visual approach Runway XX; I advised him that he was following the C130s and I fully expected to have the required separation to touchdown when I frequency changed him to Tower. Tower called not long afterward and coordinated a 360 for aircraft Y for spacing; which I approved. As I looked at the situation; I realized that the C130 flight had flown a wider pattern than I had expected and that aircraft Y had kept his speed up longer as well. I'm mostly certain that Aircraft Y's altitude was well above the C130s; but I'm not 100% sure. It's been nagging at me; though; that I'm not sure whether I lost wake turbulence separation or not; which is why I am choosing to report it. I should have either had Aircraft Y report the C130s in sight and instructed him to maintain visual separation or kept him wider longer before cutting him loose on the visual to ensure there was absolutely no way he could catch them. It was early in my shift and it was one of those days when I personally felt a little behind the eight ball before I even talked to any aircraft. I made the mistake of ignoring that personal indicator and not giving a little extra room as I normally would on those rare occasions I feel that way.

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.