Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Chart Or Publication; Human Factors
On arrival with vogler transition to join localizer 27L; crew momentarily overshot localizer course.Better understanding that 'VOGLR' transition to join 27L localizer does not include CENAK waypoint overfly.
We were cleared to fly the WATSN2 RNAV arrival into ORD. After STYLE and before VOGLR; the controller told us to 'Fly the VOGLR Transition'. With very little time; the Captain and First Officer reviewed the arrival again and could find no transition on the arrival. We both agreed that the arrival instructed us to depart CENAK on a heading of 270 or assigned; and expect radar vectors to final approach course. We flew the remainder of the arrival as published; and from CENAK; we turned to 270 degree heading. The Controller then asked us if we had 'missed the turn'; and instructed us to fly heading 250 and intercept the final approach course for Runway 27L. We complied and intercepted the 27L final approach course. VOGLR is listed as an IAF for the ILS 27L approach; and I believe the controller wanted us to depart VOGLR and fly course 281 to NRMAH and intercept the final approach course; even though we were not cleared for the approach when the event occurred. The WATSN2 Arrival instructs crews to fly from VOGLR to CENAK; then turn to heading 270; however; the ILS 27L approach can begin at VOGLR. The crew was confused as to what exactly the controller wanted. The crew should have queried the controller and verified exactly what he expected us to do. Next; the WATSN2 Arrival should have transitions listed if ATC expects crews to fly 'transitions' off of the arrival. In addition; the IAP's should have approach transitions listed if crews are expected to fly 'transitions'. Reference the ILS 35R at KDEN. The WATSN2 and the ILS 27L; do not seem to have a seamless transition. It would have been more clear if we were cleared for the approach prior to VOGLR. The crew should have recognized that this clearance is not commonly given at this airport and immediately asked for clarification from the controller.
ERJ-175 flight crew reported some confusion on what constituted their cleared track on the WATSN2 RNAV arrival to ORD.