B737 Undifferentiated or Other Model
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 10
Workload; Training / Qualification; Time Pressure; Situational Awareness; Human-Machine Interface; Communication Breakdown; Confusion; Distraction
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance
Procedure; Human Factors
Conducting OJTI [On the Job Training Instruction] at this time. Aircraft X was on a downwind from the west and issued a 360 heading which would be a base turn. Aircraft Y was on a 340 heading from the southeast. After issuing Aircraft X a 360 heading; Aircraft Y was given direct to SAILZ which is a point on the approach that tracks a 280 heading and descended to 3000. Next Aircraft X was issued direct SAILZ and given an approach clearance. Aircraft X read back both of the control instructions; but never executed the turns. Aircraft Y was turned to a 330 heading; and then I took over the frequency and vectored Aircraft X to a 270 heading. The trainee keyed up after this transmission and told Aircraft X to turn to a 140 heading; I took control of the frequency and turned Aircraft X to a 270 heading and vectored Aircraft Y north then east away from Aircraft X. After landing the pilot called and said it was a pilot deviation. He had his FMS incorrectly programmed and was navigating towards STERE; which is a point east of Sails. That would be about a 060 heading. The Falcon data showed the mileage as 1.53 NM and 0 feet. During this time the Conflict Alert never went off. That would have been helpful. We could have kept Aircraft Y at 4000 until we saw Aircraft X execute both instructions.Also; I spoke with the trainee and explained that once I take over the frequency; they are no longer allowed to talk on the frequency until I'm ready to give it back up. It would have been helpful if the Conflict Alert went off.
C90 TRACON Controller reported while providing On the Job Training Instruction; an aircraft did not turn as instructed. The developmental turned the aircraft to a different heading and complicated matters; which led to the loss of separation.