When cleared sequentially for two different but similar RNAV stars into den the flight crew of an em...

Narrative:

Our original clearance was direct mnnow and wahuu one arrival; later changed to direct mnnow for the kohoe 2 RNAV STAR. When on the arrival we were cleared direct sayge and descend via the kohoe 2. Upon crossing sayge at 20;000 ft and slowing to 250; we were switched to approach who advised to expect landing 35R. I entered the runway in the FMS and verified it with the captain. I started to review the next crossing restrictions when I noticed the fix was not in the FMS. I checked the FMS arrival page and discovered it was back to the wahuu one arrival. I selected heading and turned to the left and reselected the arrival and was reprogramming the FMS when approach told us to turn direct the den VOR and asked what we were doing arrival wise. The captain informed them of our problems and ATC re-cleared us to the VOR and descend to 13;000 ft. The primary problems were: the FMS doing strange things like selecting a different arrival when not commanded to do so. Having 3 or 4 RNAV arrivals with the same fixes and having ATC change arrivals at will. RNAV arrivals are getting to be more trouble than they are worth.

Original NASA ASRS Text

Title: When cleared sequentially for two different but similar RNAV STARs into DEN the flight crew of an EMB-145 ended up confused miss-programmed and off course. ATC provided a simple clearance direct to the VOR with a hard altitude to resolve the dilemma.

Narrative: Our original clearance was direct MNNOW and WAHUU one arrival; later changed to direct MNNOW for the KOHOE 2 RNAV STAR. When on the arrival we were cleared direct SAYGE and descend via the KOHOE 2. Upon crossing SAYGE at 20;000 FT and slowing to 250; we were switched to approach who advised to expect landing 35R. I entered the runway in the FMS and verified it with the Captain. I started to review the next crossing restrictions when I noticed the fix was not in the FMS. I checked the FMS arrival page and discovered it was back to the WAHUU one arrival. I selected HDG and turned to the left and reselected the arrival and was reprogramming the FMS when Approach told us to turn direct the DEN VOR and asked what we were doing arrival wise. The Captain informed them of our problems and ATC re-cleared us to the VOR and descend to 13;000 FT. The primary problems were: the FMS doing strange things like selecting a different arrival when not commanded to do so. Having 3 or 4 RNAV arrivals with the same fixes and having ATC change arrivals at will. RNAV arrivals are getting to be more trouble than they are worth.

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.

Attributes
ACN	1110367
Time
Date	201308
Local Time Of Day	1201-1800
Place
Locale Reference	ZDV.ARTCC
State Reference	CO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	EMB ERJ 145 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	First Officer
Events
Anomaly	ATC Issue All Types Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Track / Heading All Types

When cleared sequentially for two different but similar RNAV stars into den the flight crew of an emb-145 ended up confused miss-programmed and off course. ATC provided a simple clearance direct to the VOR with a hard altitude to resolve the dilemma.