Air Traffic Control Fully Certified
Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors; Procedure
A Hawker was on a vector for Runway 01C at 3;000 FT and a CRJ was on downwind for Runway 01L. I turned the CRJ on a base heading a descended them to 3;000 FT. I had planned on the CRJ turning in front of the Hawker; however due to the new GIBBZ RNAV arrival; the CRJ was further west and heading southwest. This resulted in the CRJ making a wider turn than I'm used too; because of this wide turn I lost separation with the CRJ and the Hawker prior to the CRJ having the airport in sight. I would recommend moving the fix SIYOB on the GIBBZ arrival to the west as this would allow a heading between SIYOB and MIKEJ that would parallel the final approach course. Also; with the new arrival the airspace boundary with final and Tilly Sector is further south and this makes it harder to descend the arrivals on downwind and turn towards the airport.
PCT Controller experienced a loss of separation event between two arrivals to IAD. The reporter listed the new GIBBS RNAV STAR's track as contributing to the event.