Narrative:

Aircraft X was sswbound descending to 7000 ft when aircraft Y departed swf airport nwbound climbing to 6000 ft but requesting FL300. Recognizing that aircraft X was a B752 and anticipating the use of visual separation; as the visibility was very good; I stopped aircraft X descent at 10000 ft. This would keep its airspeed at the assigned 290 KTS or greater; minimizing wake. Then I climbed aircraft Y to 9000 ft and; once it'd entered my airspace; vectored it to heading 300 degrees to keep it from entering any area of wake. I issued traffic to both aircraft; including types; and they reported each other in sight. Aircraft Y was at the 11 O'clock position at approximately 5 mi in front of aircraft X crossing perpendicularly and I advised aircraft Y that targets may merge. I then instructed aircraft Y to maintain visual separation from that traffic and to climb to 17000 ft. Aircraft Y advised me that they would wait until they were clear to climb to 17000 ft. I advised aircraft X that the traffic would maintain visual separation. When aircraft Y was at about the 4 O'clock position of aircraft X and about 2 mi clear; I slowed aircraft X to 250 KTS and later descended it to 7000 ft. It is claimed that; because aircraft Y wasn't issued a cautionary wake turbulence advisory; the requirements for visual separation had not been met and; therefore; there was a loss of standard separation. The only reason that this event has been characterized by our management as an operational error is because the FAA has written the requirements for visual separation in a manner that is nonsensical. I applied visual separation based upon the situation and my knowledge of the characteristics of wake turbulence. In this instance there would be no wake and; therefore; no need for a wake advisory to these professional airline pilots. Air traffic publication 7110.65; however; apparently does not allow the controller to use his judgement; instead stating that a cautionary wake turbulence advisory must be issued whenever visual separation is being applied between any aircraft and a heavy jet or B757; whether or not there is any possibility of encountering any wake. The 7110.65 could and should be better written; provide some explanation; and offer more guidance in these other aspects of visual separation to provide better service to the user and a more workable product for the controller.

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Original NASA ASRS Text

Title: ZBW CTLR EXPERIENCED OPERROR AT 10000 FT WHEN ATTEMPTING TO APPLY VISUAL SEPARATION PROCS TO A WAKE TURBULENCE SEPARATION EVENT.

Narrative: ACFT X WAS SSWBOUND DSNDING TO 7000 FT WHEN ACFT Y DEPARTED SWF ARPT NWBOUND CLBING TO 6000 FT BUT REQUESTING FL300. RECOGNIZING THAT ACFT X WAS A B752 AND ANTICIPATING THE USE OF VISUAL SEPARATION; AS THE VISIBILITY WAS VERY GOOD; I STOPPED ACFT X DSCNT AT 10000 FT. THIS WOULD KEEP ITS AIRSPD AT THE ASSIGNED 290 KTS OR GREATER; MINIMIZING WAKE. THEN I CLBED ACFT Y TO 9000 FT AND; ONCE IT'D ENTERED MY AIRSPACE; VECTORED IT TO HDG 300 DEGS TO KEEP IT FROM ENTERING ANY AREA OF WAKE. I ISSUED TFC TO BOTH ACFT; INCLUDING TYPES; AND THEY RPTED EACH OTHER IN SIGHT. ACFT Y WAS AT THE 11 O'CLOCK POS AT APPROX 5 MI IN FRONT OF ACFT X XING PERPENDICULARLY AND I ADVISED ACFT Y THAT TARGETS MAY MERGE. I THEN INSTRUCTED ACFT Y TO MAINTAIN VISUAL SEPARATION FROM THAT TFC AND TO CLB TO 17000 FT. ACFT Y ADVISED ME THAT THEY WOULD WAIT UNTIL THEY WERE CLR TO CLB TO 17000 FT. I ADVISED ACFT X THAT THE TFC WOULD MAINTAIN VISUAL SEPARATION. WHEN ACFT Y WAS AT ABOUT THE 4 O'CLOCK POS OF ACFT X AND ABOUT 2 MI CLR; I SLOWED ACFT X TO 250 KTS AND LATER DSNDED IT TO 7000 FT. IT IS CLAIMED THAT; BECAUSE ACFT Y WASN'T ISSUED A CAUTIONARY WAKE TURB ADVISORY; THE REQUIREMENTS FOR VISUAL SEPARATION HAD NOT BEEN MET AND; THEREFORE; THERE WAS A LOSS OF STANDARD SEPARATION. THE ONLY REASON THAT THIS EVENT HAS BEEN CHARACTERIZED BY OUR MGMNT AS AN OPERROR IS BECAUSE THE FAA HAS WRITTEN THE REQUIREMENTS FOR VISUAL SEPARATION IN A MANNER THAT IS NONSENSICAL. I APPLIED VISUAL SEPARATION BASED UPON THE SITUATION AND MY KNOWLEDGE OF THE CHARACTERISTICS OF WAKE TURB. IN THIS INSTANCE THERE WOULD BE NO WAKE AND; THEREFORE; NO NEED FOR A WAKE ADVISORY TO THESE PROFESSIONAL AIRLINE PLTS. AIR TFC PUB 7110.65; HOWEVER; APPARENTLY DOES NOT ALLOW THE CTLR TO USE HIS JUDGEMENT; INSTEAD STATING THAT A CAUTIONARY WAKE TURB ADVISORY MUST BE ISSUED WHENEVER VISUAL SEPARATION IS BEING APPLIED BTWN ANY ACFT AND A HVY JET OR B757; WHETHER OR NOT THERE IS ANY POSSIBILITY OF ENCOUNTERING ANY WAKE. THE 7110.65 COULD AND SHOULD BE BETTER WRITTEN; PROVIDE SOME EXPLANATION; AND OFFER MORE GUIDANCE IN THESE OTHER ASPECTS OF VISUAL SEPARATION TO PROVIDE BETTER SVC TO THE USER AND A MORE WORKABLE PRODUCT FOR THE CTLR.

Data retrieved from NASA's ASRS site as of May 2009 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.