Narrative:

I was training on an arrival position in a north flow. My developmental is close to check out so I was trying to let him/her 'work' the traffic. I knew that aircraft X was going to be close behind aircraft Y {a heavy B757} & prompted him to level aircraft X at 4000 MSL & slow him more before descending. Aircraft Y heavy was at 3000 MSL at that time & even though the ATIS advertised ILS approaches; we were getting visuals at 3000 MSL & below. Aircraft Y heavy was on a visual approach & was on a four mile final on the tower frequency. Aircraft X saw the field but not the B757 so my developmental cleared him & vectored him to join final six to seven miles from the field. I had a five mile j-ring on aircraft Y heavy & a five mile 'P' leader line on aircraft X. If aircraft X flew the heading he was told to join the final he would be over five miles behind the heavy B757 but he was coming up on the five mile J ring of the heavy B757 & I don't know the exact path that aircraft Y heavy took to join final. Aircraft X saw the heavy B757 & was instructed to follow that traffic. I don't know if he was five or 4.9 miles away. We have been told that a heavy aircraft leaves wake turbulence five miles behind & a mile wide but I don't know if aircraft X was in his remnants since we can't see them! I do know that if aircraft X followed his vector he would join final more than five miles behind the heavy B757! What are wake turbulence remants? I cannot find any written rule defining them!!! Do they go up at all and if so how far? I have heard that they are a mile wide but once again I can't find that in writing! It's very hard to train somebody & tell them to avoid something that is not defined! It's a credibility issue and credibility is needed to train someone! My recommendation is this: get ato (air traffic organization) safety or aov (air traffic safety oversight service) or whoever dreamed up wake turbulence remnants to define them & put it in the 7110.65! Then allow us to see them on our radar scopes.

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Original NASA ASRS Text

Title: An Approach Controller reported that controllers are supposed to separate from wake turbulence remnants which are not depicted nor defined.

Narrative: I was training on an arrival position in a north flow. My developmental is close to check out so I was trying to let him/her 'work' the traffic. I knew that Aircraft X was going to be close behind Aircraft Y {a Heavy B757} & prompted him to level Aircraft X at 4000 MSL & slow him more before descending. Aircraft Y Heavy was at 3000 MSL at that time & even though the ATIS advertised ILS approaches; we were getting visuals at 3000 MSL & below. Aircraft Y Heavy was on a visual approach & was on a four mile final on the Tower Frequency. Aircraft X saw the field but not the B757 so my Developmental cleared him & vectored him to join final six to seven miles from the field. I had a five mile J-ring on Aircraft Y Heavy & a five mile 'P' leader line on Aircraft X. If Aircraft X flew the heading he was told to join the final he would be over five miles behind the Heavy B757 but he was coming up on the five mile J ring of the heavy B757 & I don't know the exact path that Aircraft Y Heavy took to join final. Aircraft X saw the Heavy B757 & was instructed to follow that traffic. I don't know if he was five or 4.9 miles away. We have been told that a Heavy aircraft leaves wake turbulence five miles behind & a mile wide but I don't know if Aircraft X was in his remnants since WE CAN'T SEE THEM! I do know that if Aircraft X followed his vector he would join final more than five miles behind the Heavy B757! What are WAKE TURBULENCE REMANTS? I cannot find any written rule defining them!!! Do they go up at all and if so how far? I have heard that they are a mile wide but once again I can't find that in writing! It's very hard to train somebody & tell them to avoid something that is not defined! It's a credibility issue and credibility is needed to train someone! My recommendation is this: Get ATO (Air Traffic Organization) Safety or AOV (Air Traffic Safety Oversight Service) or whoever dreamed up wake turbulence remnants to define them & put it in the 7110.65! Then allow us to see them on our radar scopes.

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.