Date: 201810
Local time of day: 1201-1800
Location: LAS.Airport, NV
Flight conditions: VMC
Aircraft: B767 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Initial Approach
Airspace: Class B LAS
ATC / advisory: TRACON L30
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Situational Awareness; Communication Breakdown; Time Pressure
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Became Reoriented
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: We were filed and cleared the TYSSN5 RNAV arrival into Las Vegas. We had briefed the RNAV GPS to 19L. We were vectored off the arrival after KADDY and told to expect direct to LOOSN and the SITEE3 arrival. I gave the airplane to my first officer while I briefed the new arrival. After I took the airplane back. We were stepped down in altitude to 6000 ft as we approached LOOSN. Approximately at LOOSN we were given a clearance 'turn left to 270 cleared the RNAV Visual to Runway 19L.' We were expecting the RNAV GPS backed up by the visual; so it did not initially dawn on us what he had cleared us for. Shortly thereafter he came back and said he had given us an incorrect clearance and told us to return to the SITEE. We had already cleared out the SITEE and from our current position it would have been difficult to return to the arrival prior to the end of the arrival. My First Officer told the Controller that we had dumped the SITEE arrival and wished to fly 'the visual.' We were then cleared the visual. We were confused by the clearance for an RNAV Visual as it is not in our JEPPFD-PRO app and we were expecting to fly a visual backed up with the RNAV. The multiple clearance changes requiring FMS programming in close proximity to the field caused us to become task saturated and led to a situation where communication between the Controller and aircrew became unclear. My First Officer did a good job trying to mitigate the problem by getting us the visual approach. I believe we complied with the clearances as given; but this situation could have easily caused us to accept a bad clearance or to fail to follow a clearance correctly. Crews should be aware that this RNAV Visual exists in case it is given and be ready to get a different clearance since we do not have approval for this approach. Multiple FMS changes near the field coupled with expectation bias could have led to us not complying with our clearance or accepting a clearance for a procedure we are not approved to fly. Better training on the existence of RNAV visuals at different fields; the requirements for flying them would have helped us combat the expectation bias that occurred with the RNAV backed up with a visual and the RNAV Visual. Our guidance in the FOM on RNAV Visual Approaches is also not clear. In one place it specifies the RNAV Visual [at a different airport] as being the only one approved; but in another place the RNAV Visual is discussed as though we can fly them as long as certain other requirements are met.




Synopsis: B767 Captain reported multiple clearance changes on approach to LAS resulted in some confusion and workload issues.