Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 10
Confusion; Distraction; Troubleshooting
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Separated Traffic
Aircraft; Human Factors; Procedure
Aircraft X was level climbing to 9;000 FT direct PTW in front of Aircraft Y about 5 miles. Aircraft Y was out of 10;000 FT climbing to 13;000 FT. When Aircraft Y vacated 11;000 FT; I climbed Aircraft X to 11;000 FT. After about a minute or two I noticed that Aircraft Y stopped his climb at 11;400 FT. It appeared that the Aircraft Y stayed at 11;400 for about a minute before starting his climb again. I had already switched Aircraft Y to ZNY Center; so I could not ask him to expedite his climb. When I noticed Aircraft Y leveling off at 11;400; I noticed Aircraft X vacating 10;000 FT. I advised Aircraft X to stop his climb at 10;400 FT. The pilot acknowledged and read back maintain 10;400 FT. It appeared that Aircraft X climbed to 10;600 FT before descending back to 10;400 FT. After calling the ZNY PTW Sector to ask if they knew why Aircraft Y stopped his climb; they replied they didn't know; he checked on and said he was climbing to 13;000 FT. It seemed that the stop climb from Aircraft Y at 11;400 was a direct result of the possible loss of separation.
Aircraft Y departed Runway 27L on the SID (268 heading) climbing to 5;000 FT. I radar identified him. Aircraft Z departed Runway 27L on the SID (268 heading) and I radar identified that aircraft and climbed him to 10;000 FT. I made a couple of other transmissions to other aircraft then came back to Aircraft Y and climbed him to 10;000 FT. After making several other transmissions to other aircraft I noticed that Aircraft Z was gaining speed and catching up to Aircraft Y. I advised Aircraft Z to reduce his speed and issued a turn of 210 degrees to avoid the potential conflict. I had Aircraft X that departed Runway 35 on a 310 degree heading prior to Aircraft Y departing Runway 27L. I wanted to climb Aircraft Y to top Aircraft X going to the same fix; PTW; so I keep him on the SID for a few extra miles. Due to the faster aircraft behind Aircraft Y (Aircraft Z); I should have issued a 290 degree heading to Aircraft Y. This would have prevented the possible loss of separation.
PHL Controller reports of loss of separation between two aircraft under his control. Use of anticipated separation was a factor. He then reports of a second incident involving a third aircraft where speed control and vectoring play a part in another conflict.