Narrative:

I was one of two iros on our flight to den. We were filed and cleared to descend via the moltn RNAV STAR. Early in the arrival phase; we were told to expect the ILS runway 34R. About 3-4 miles prior to himom fix on the arrival; we were told to change our approach to the RNAV Z 34L. Almost immediately we were given the clearance; 'at himom cleared the RNAV Z 34R.' [predictably] the aircraft's FMS and mouse pad cursor allows nothing to happen 'quickly' in setting up the FMS for last minute approach changes. Being only a 'few miles' from the RNAV Z if [initial fix] (himom) it took us time to set up the approach and sequence the legs page so that the automation [matched our clearance]. In doing so; we flew past himom; and the autopilot did not sequence correctly [via the approach transition] himom; mcmul; bsayn; etc. The plane kept tracking south past himom. The crew and ATC coordinated a southerly vector with by which to set up for a visual approach to runway 34R. To our knowledge traffic separation was never lost and the approach was completed without incident.

Google
 

Original NASA ASRS Text

Title: A late runway change clearance as the airliner was only a few miles from the runway transition IF resulted in a temporary track deviation as the flight crew attempted to program the change. ATC provided vectors for the subsequent approach.

Narrative: I was one of two IROs on our flight to DEN. We were filed and cleared to descend VIA the MOLTN RNAV STAR. Early in the arrival phase; we were told to expect the ILS Runway 34R. About 3-4 miles prior to HIMOM fix on the arrival; we were told to change our approach to THE RNAV Z 34L. Almost immediately we were given the clearance; 'at HIMOM cleared the RNAV Z 34R.' [Predictably] the aircraft's FMS and mouse pad cursor allows nothing to happen 'quickly' in setting up the FMS for last minute approach changes. Being ONLY a 'few miles' from the RNAV Z IF [Initial Fix] (HIMOM) it took us time to set up the approach and sequence the legs page so that the automation [matched our clearance]. In doing so; we flew past HIMOM; and the autopilot did not sequence correctly [via the approach transition] HIMOM; MCMUL; BSAYN; etc. The plane kept tracking south past HIMOM. The crew and ATC coordinated a southerly vector with by which to set up for a Visual Approach to Runway 34R. To our knowledge traffic separation was never lost and the approach was completed without incident.

Data retrieved from NASA's ASRS site as of July 2013 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.