BAe 125 Series 800
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Human Factors
We were approaching CYVR on the Grizz5 arrival landing east (8R). On downwind we called field in sight and were cleared the visual approach except maintain on or south of the 8R localizer; because another aircraft from the north side of the airport was doing the mirror image of us. The localizer signal was preprogrammed in FMS. During the base to final turn (where it was imperative to remain on or south of the localizer); the Controller pointed out our traffic. I scanned out the left window (I was Non Flying pilot in right seat) and as I found the traffic and returned to scan inside; the Controller said to us we were showing north of the center line. As I then looked forward out the window we appeared very slightly off center line; the localizer needle was less than half of its width off. During the event the pilot flying had the autopilot on and was using heading mode to capture the localizer centerline. The Collins FMS will usually automatically switch to localizer and track inbound if set up properly. This time it did not and the Pilot flying did not take the appropriate action (click off the auto pilot) to remain on the centerline. We as pilots need to stop letting the automation get in the way of flying the airplane and complying with ATC instructions.
HS-125-800XPC Captain reported a track deviation on approach to CYVR.