Tracon controller reported that when an airbus followed a B744 on the same SID; aircraft performance...

Narrative:

I was providing otj to a controller in training. Traffic was light; but we were in the middle of a runway change. Aircraft X departs runway xxl on departure SID; a left turn toward VOR to intercept an outbound radial to the south. Aircraft X was turned to a 090 heading and climbed to 7;000. Aircraft Y departs next; on the same SID; but since the A320 rotates before the B744; he turns inside the track of the B744. Aircraft Y is also turned east; 100 or 110 heading I think. I have not listened to the tape yet. Again; the A320 performs differently and turns pretty quick; therefore cutting off more of the track of the B744. This; I believe; is not realized by the trainee. I place a j ring on the B744 and we are very close. I take the frequency; call the traffic and ask aircraft Y if he has it in sight. Aircraft Y acknowledges that he does and I instruct him to maintain visual separation; caution wake turbulence.the question now is if I was able to apply the visual separation before I lost separation. It may have been lost before aircraft Y was turned. But since we turned the aircraft X off the SID; I would have to assume that we buy it; not the tower. The loss was a remnant violation. 4.99 miles when 5.0 was needed; and I think the A320 was never less than 1;000 below the B744. That is what I don't understand about the whole remnant issue.

Original NASA ASRS Text

Title: Tracon Controller reported that when an Airbus followed a B744 on the same SID; aircraft performance characteristics led to a compromise in separation. The result was a 'wake remnant' violation.

Narrative: I was providing OTJ to a Controller in training. Traffic was light; but we were in the middle of a runway change. Aircraft X departs Runway XXL on departure SID; a left turn toward VOR to intercept an outbound radial to the south. Aircraft X was turned to a 090 heading and climbed to 7;000. Aircraft Y departs next; on the same SID; but since the A320 rotates before the B744; he turns inside the track of the B744. Aircraft Y is also turned east; 100 or 110 heading I think. I have not listened to the tape yet. Again; the A320 performs differently and turns pretty quick; therefore cutting off more of the track of the B744. This; I believe; is not realized by the trainee. I place a j ring on the B744 and we are very close. I take the frequency; call the traffic and ask Aircraft Y if he has it in sight. Aircraft Y acknowledges that he does and I instruct him to maintain visual separation; caution wake turbulence.The question now is if I was able to apply the visual separation before I lost separation. It may have been lost before Aircraft Y was turned. But since we turned the Aircraft X off the SID; I would have to assume that we buy it; not the tower. The loss was a remnant violation. 4.99 miles when 5.0 was needed; and I think the A320 was never less than 1;000 below the B744. That is what I don't understand about the whole remnant issue.

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.

Attributes
ACN	934145
Time
Date	201102
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Aircraft 1
Make Model Name	B747-400
Operating Under FAR Part	Part 121
Flight Phase	Initial Climb
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Initial Climb
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Departure
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

Tracon controller reported that when an airbus followed a B744 on the same SID; aircraft performance characteristics led to a compromise in separation. The result was a 'wake remnant' violation.