Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 17.7
Confusion; Distraction
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Human Factors; Procedure
Aircraft X was cleared for a visual approach to RWY 24.  He was flying approximately a 270 heading directly to the airport when I transferred him to the tower about 10 miles from the airport.  Aircraft Y was on a 090 heading about 6 miles northwest of Aircraft X when I gave him a 120 heading to fall behind Aircraft Y.  When I looked back at the radar to see if I could turn Aircraft Y inbound; I observed Aircraft X directly ahead of Aircraft Y.I turned Aircraft Y back to a 060 heading; and he reported the traffic in sight.  I then cleared Aircraft Y behind Aircraft X.  What I was unaware of was that the local controller had told Aircraft X to square off his turn to final.  This caused Aircraft X to turn 40-60 degrees to the northwest of his current approach course.  It put Aircraft X and Aircraft Y in a head to head situation instead of Aircraft Y being on a vector behind the course of Aircraft X.  The local controller never called me to coordinate the turn for Aircraft X.There needs to be a clear definition for when the local controller can turn an aircraft sequenced by the arrival controller. Decisions on sequencing for visual approaches are made with current aircraft tracks in mind when you're turning the next aircraft to follow. An uncoordinated turn by the local controller can easily cause a loss of separation with the following aircraft if the change in course is not observed in time.
Working Local control. I had one aircraft in the left downwind with another arrival behind him in left traffic.  Four or five Jets inbound taking visual approaches from the east and north landing RWY 24 (RWY13/31 Closed).  I had given the small aircraft a right 360 in the downwind to allow spacing for a few of the Jet arrivals; the other VFR was to follow the jet on final and keep it tight if able.  Aircraft X checked in 7-9 miles east of the field on Visual approach at a high rate of speed.  I told Aircraft X to 'Square his base turn to final' and told him about the aircraft traffic he was following. At the time Aircraft Y was still on the northeast heading at 3;000 feet.  Aircraft Y appeared to have received his base turn the same time I gave the Aircraft X his instructions to space him behind the downwind traffic.  I exchanged traffic to Aircraft X and informed him that I did have both aircraft in sight and was maintaining visual from the tower.  Aircraft Y turned back out and re-sequenced behind Aircraft X. I didn't report the incident when it happened because although I was surprised by the Aircraft Y's turn inbound; I had good visibility on both aircraft and I had space to work the Aircraft Y behind the Aircraft X even from the tight base.  I have been informed that the incident is being reviewed for possible OE/OD. *The shift times and breaks are estimated because I don't have the logs from the day with me for this report. In the past; when working Local control I would always have the Arrival frequency playing in the back of the tower over a speaker. It allowed me to hear inbound emergencies sooner; frequency changes to the tower (or not); the general flow of what aircraft coming to my final are doing; and what they have been told (other traffic; closed runways; bird and wind-shear reports) I felt much more connected to the big picture and could better work with the arrival controller. Due to a procedural change last year in the SOP stemming from a runway incursion; the facility has banned monitoring the arrival frequencies while working Local control. If I had been monitoring the arrival frequency I would have heard the Aircraft Y's inbound turn and I could have maneuvered the Aircraft X a bit closer to the field and sent the VFR around for another pass.
ABE TRACON and tower controllers describe a situation where two aircraft became a conflict resulting in traffic breaking themselves out to re-sequence.