A B737-800 crew reported changing the FMS to the moltn two RNAV and the approach from the ILS 34R to...

Attributes
ACN	1173110
Time
Date	201405
Local Time Of Day	0601-1200
Place
Locale Reference	D01.TRACON
State Reference	CO
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Route In Use	STAR MOLTN TWO RNAV
Flight Plan	IFR
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 12000 Flight Crew Type 30
Person 2
Function	Pilot Not Flying First Officer
Experience	Flight Crew Last 90 Days 160 Flight Crew Total 11500 Flight Crew Type 3000
Events
Anomaly	ATC Issue All Types Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types

Narrative:

Original clearance was the tshnr one RNAV arrival into denver. After checking ATIS; we asked if we should expect the moltn two arrival since denver was landing north. We were then re-cleared for the moltn two arrival to wooky. I had briefed the visual backed up by the ILS to 34R at 80 miles before TOD. The ATIS said to expect visual or ILS to 34R; 35L; rnpz approach available. When we checked in with approach near ramms we were told to expect the RNAV rnpz 34R approach. We had to hurry to change the FMC from the ILS 34R to the RNAV rnpz 34R with little time to brief and reset everything at a very busy time of the arrival. Approaching himom we were cleared to descend to 9;000 feet. At himom is where things became more confusing. While descending to 9;000 feet and just past himov; we were given a turn to 80 heading. They called traffic for 35L which we reported in sight. In my recollection; this turn occurred before mcmul or kalme. In either case; we thought we were still on the 173 track. At this point; we didn't know if we were cleared for the rnpz approach or not. A suggestion that would help the pilots as well as the controllers would be to get a definite clearance for the RNAV rnpz approach well before himom to prevent unstable approaches or inability to even fly the approach properly and to avoid any confusion as to what the clearance is.

Original NASA ASRS Text

Title: A B737-800 crew reported changing the FMS to the MOLTN TWO RNAV and the approach from the ILS 34R to the RNAV RNPZ 34R and while on a vector the crew and ATC was uncertain if they were cleared for the approach.

Narrative: Original clearance was the TSHNR ONE RNAV arrival into Denver. After checking ATIS; we asked if we should expect the MOLTN TWO arrival since Denver was landing north. We were then re-cleared for the MOLTN TWO arrival to Wooky. I had briefed the visual backed up by the ILS to 34R at 80 miles before TOD. The ATIS said to expect visual or ILS to 34R; 35L; RNPZ approach available. When we checked in with approach near RAMMS we were told to expect the RNAV RNPZ 34R approach. We had to hurry to change the FMC from the ILS 34R to the RNAV RNPZ 34R with little time to brief and reset everything at a very busy time of the arrival. Approaching HIMOM we were cleared to descend to 9;000 feet. At HIMOM is where things became more confusing. While descending to 9;000 feet and just past HIMOV; we were given a turn to 80 heading. They called traffic for 35L which we reported in sight. In my recollection; this turn occurred before MCMUL or KALME. In either case; we thought we were still on the 173 track. At this point; we didn't know if we were cleared for the RNPZ approach or not. A suggestion that would help the pilots as well as the controllers would be to get a definite clearance for the RNAV RNPZ approach well before HIMOM to prevent unstable approaches or inability to even fly the approach properly and to avoid any confusion as to what the clearance is.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

A B737-800 crew reported changing the FMS to the moltn two RNAV and the approach from the ILS 34R to the RNAV rnpz 34R and while on a vector the crew and ATC was uncertain if they were cleared for the approach.