Regional Jet 900 (CRJ900)
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Communication Breakdown; Human-Machine Interface
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Returned To Clearance
Aircraft; Human Factors
While descending on the Bluzz2 arrival; we were assigned Runway 36R. Runway 36L had been loaded into the FMS; so as PF (Pilot Flying) I reloaded the approach and landing speeds. After hitting 'execute'; the aircraft initiated a 180 degree turn because while loading the approach; we passed the LTOWN fix. I selected heading on the FCP; selected DAPLE on the FMS; and executed that. I don't know if I selected NAV mode or not; but I suspect I didn't. The aircraft flew on course until CLARK; at which time it continued on a heading. I noticed we were off course; disengaged the autopilot and turned back to the course. A couple of seconds after that; MEM Approach gave us a heading of 160; which appeared to be a heading to get us back on course; and 4000 ft. A few seconds after that; the heading was changed to 170. We were vectored the rest of the way to the airport. As PF; I don't think I articulated the FMA calls appropriately; so the pilot monitoring wasn't sure what was happening and so he wasn't able to properly monitor the aircraft course. If I had been more inclusive; this event probably wouldn't have happened. Always call out FCP mode changes and always verify them on the FMA.
CRJ-900 Captain reported mismanagement of FMS and CRM resulted in being off course.