Date: 201811
Local time of day: 0601-1200
Location: DEN.Airport, CO
Flight conditions: VMC
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B DEN
ATC / advisory: TRACON D01
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Situational Awareness; Time Pressure
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: On arrival to DEN we flew ANCHR 4 RNAV while planning for ILS 35L Approach. When switched to initial Approach Controller; were given ILS 35R. Changed approach; programmed box; rebriefed; continued on. Once in terminal area passing FULLA and approaching FFFAT we were given new approach to RNAV (RNP) Z 35R; assigned speed of 210 at DOGGG. Changed approach; programmed box; attempted briefing while programming; [and] continued on. Shortly thereafter; Approach Controller asked why we refused to accept RNAV 35R Approach. Wasn't clear on what prompted that inquiry; but immediately following it; we were given a heading to fly (right turn); then asked to report the airport for a Visual Approach 35R. Then another heading (further right) to intercept the localizer for ILS 35R. We flew a visual/backed ILS approach to 35R. Landed uneventfully. Taxied to gate. I requested a number to contact the Controller upon completion of flight. After deplaning; we discussed/debriefed the flight and in particularly the sequence of events during the terminal phase of flight. While approach didn't query our position (RNAV phase of approach) I suspect I may have flown over the waypoint from which I was to start the turn towards the runway (time/distance between where given new approach and beginning of RNAV approach wasn't sufficient to properly perform required duties. ie; program and properly sequence waypoints). While enroute to the hotel I contacted the Center and spoke with the Operational Supervisor. We had a good lengthy discussion and debrief about what transpired; from their perspective and from our perspective. Exchanged input as to what could have been done to make that sequence of events more smooth and less complicated for the both of us. He said he was going to submit an internal report on the event explaining how they can better assist us (arriving aircraft) without unknowingly increasing our workload. And we; pilots; [should] not be hesitant/intimidated to refuse a particular approach because of the workload factor and/or time constraint in preparing the approach/landing may present.




Synopsis: B757 Captain reported a track deviation occurred on the RNAV (RNP) Z Approach to 35R in DEN; when an FMC programming error occurred following a late clearance change.