Narrative:

First day working busy traffic with new oapm (optimization of airspace and procedures metroplex) opd (optimal profile descent) arrival procedures. The new procedures are complex and take much of your attention because all aircraft come over 'descending via' the procedure and are not level at hard altitudes. The center sector is now allowed to feed dual arrivals which must be blended into a single stream; which is extremely difficult when it is hard to establish altitude separation. While working out a handful of arrivals that needed to be blended together I was late in slowing an aircraft about to turn the downwind. I may have used the wrong call sign. Aircraft X and aircraft Y were both on the frequency. When the trailing aircraft wasn't slowing quickly enough I expedited the lead aircraft (aircraft Z) to 11000 feet to gain altitude separation; and a few seconds later I noticed the trail aircraft (aircraft Y) also descending out of 12;000 feet. I believe aircraft Y had taken the descent to 7;000 feet that was previously issued to aircraft X on the downwind. I immediately stopped aircraft Y at 11;000 feet to prevent him from descending into departure airspace; but also creating a loss of in trail separation with aircraft Z. I may be at fault for mixing up the similar callsigns or missing a readback where the descent was acknowledged by the wrong aircraft; but I believe that the 1+30 hours on position working heavy volume and added complexity of the new procedures contributed to me not catching the problem before the loss of separation.the inability of controllers to establish altitude separation quickly when blending the dual stream of arrivals has created a much more complex situation that requires a lot more of the controller's attention. This takes attention away from other areas and may cause things to go unnoticed creating losses of separation and compromising safety. Having the opd arrivals terminate at hard altitudes at the TRACON airspace boundary would make things much more manageable. The 'descending via' would not be an issue in a single arrival situation where no blending is required.

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Original NASA ASRS Text

Title: JAX TRACON Controller had a loss of separation between two arrivals while utilizing new arrival routes and procedures after confusing similar sounding call signs.

Narrative: First day working busy traffic with new OAPM (Optimization of Airspace and Procedures Metroplex) OPD (Optimal Profile Descent) arrival procedures. The new procedures are complex and take much of your attention because all aircraft come over 'descending via' the procedure and are not level at hard altitudes. The center sector is now allowed to feed dual arrivals which must be blended into a single stream; which is extremely difficult when it is hard to establish altitude separation. While working out a handful of arrivals that needed to be blended together I was late in slowing an aircraft about to turn the downwind. I may have used the wrong call sign. Aircraft X and Aircraft Y were both on the frequency. When the trailing aircraft wasn't slowing quickly enough I expedited the lead aircraft (Aircraft Z) to 11000 feet to gain altitude separation; and a few seconds later I noticed the trail aircraft (Aircraft Y) also descending out of 12;000 feet. I believe Aircraft Y had taken the descent to 7;000 feet that was previously issued to Aircraft X on the downwind. I immediately stopped Aircraft Y at 11;000 feet to prevent him from descending into departure airspace; but also creating a loss of in trail separation with Aircraft Z. I may be at fault for mixing up the similar callsigns or missing a readback where the descent was acknowledged by the wrong aircraft; but I believe that the 1+30 hours on position working heavy volume and added complexity of the new procedures contributed to me not catching the problem before the loss of separation.The inability of controllers to establish altitude separation quickly when blending the dual stream of arrivals has created a much more complex situation that requires a lot more of the controller's attention. This takes attention away from other areas and may cause things to go unnoticed creating losses of separation and compromising safety. Having the OPD arrivals terminate at hard altitudes at the TRACON airspace boundary would make things much more manageable. The 'descending via' would not be an issue in a single arrival situation where no blending is required.

Data retrieved from NASA's ASRS site 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.