Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 150; Flight Crew Total 22000; Flight Crew Type 4000
Workload; Time Pressure; Human-Machine Interface; Distraction
ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew FLC complied w / Automation / Advisory
Human Factors; Chart Or Publication; Airport; Procedure
During an RNAV arrival into DIA we received an arrival change just prior to top of descent. This occurs quite often. We reprogrammed the new arrival and began descent. Just prior to the final fix on the RNAV arrival we were cleared for the transition to the runway. Because we hadn't anticipated this clearance we were then quite busy programming the change. This all happened while receiving late descent clearance for a visual to 16L. A high descent rate then caused a TCAS RA and a level off for the parallel aircraft on 16R. This further delayed our descent. The recovery went well. All of this would never have happened in the pre-RNAV approaches. I believe the new RNAV arrivals are very problematic with all the speed and altitude restrictions. The lateral NAV is not a problem. However; the designers need to limit the altitude and speed restrictions to the minimum necessary.
Late and untimely changes to RNAV STAR assignments inbound to DIA contributed to expedited descent rates and a TCAS RA response with conflicting traffic for a B757 flight crew. The reporter commented that; while the demands of lateral nav is acceptable; the multiple airspeed and altitude constraints common to many of the RNAV STARs are distracting and require excessive flight crew attention.