A C560 crew descended from their assigned altitude prior passing the IAF on an ase VOR DME approach.

Attributes
ACN	641653
Time
Date	200412
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ase.airport
State Reference	CO
Altitude	msl single value : 13100
Environment
Flight Conditions	IMC
Weather Elements	Ice Snow
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ase.tracon
Operator	general aviation : corporate
Make Model Name	Citation V
Operating Under FAR Part	Part 91
Navigation In Use	other vortac
Flight Phase	descent : approach
Route In Use	approach : instrument non precision arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : multi engine pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 30 flight time total : 6100 flight time type : 2100
ASRS Report	641653
Person 2
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : cfi pilot : instrument pilot : multi engine pilot : atp pilot : commercial
Experience	flight time last 90 days : 60 flight time total : 3500 flight time type : 1000
ASRS Report	641655
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : far non adherence : published procedure
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : executed go around
Supplementary
Problem Areas	Flight Crew Human Performance Airspace Structure
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While being vectored for the VOR-DME 'C' approach into aspen, co, crew was vectored to the final approach course and instructed to 'maintain 14000 ft MSL until established cleared for the VOR-DME 'C' approach aspen.' once established, crew descended to next stepdown to maintain 13100 ft MSL. Crew then realized that the 13100 ft stepdown was not to take place until reaching the VOR. Crew initiated descent from 14000 ft MSL approximately 4 NM outside the dbl VOR and reached 13100 ft upon crossing the dbl VOR. Upon realizing the error crew immediately executed a missed approach. Due to the high terrain and extra attention to detail needed while traveling in and out of these mountainous airports, longer time to get established would have helped, along with ATC declaring where we were being vectored to, ie, outside dbl VOR to join final approach course.

Original NASA ASRS Text

Title: A C560 CREW DSNDED FROM THEIR ASSIGNED ALT PRIOR PASSING THE IAF ON AN ASE VOR DME APCH.

Narrative: WHILE BEING VECTORED FOR THE VOR-DME 'C' APCH INTO ASPEN, CO, CREW WAS VECTORED TO THE FINAL APCH COURSE AND INSTRUCTED TO 'MAINTAIN 14000 FT MSL UNTIL ESTABLISHED CLRED FOR THE VOR-DME 'C' APCH ASPEN.' ONCE ESTABLISHED, CREW DSNDED TO NEXT STEPDOWN TO MAINTAIN 13100 FT MSL. CREW THEN REALIZED THAT THE 13100 FT STEPDOWN WAS NOT TO TAKE PLACE UNTIL REACHING THE VOR. CREW INITIATED DSCNT FROM 14000 FT MSL APPROX 4 NM OUTSIDE THE DBL VOR AND REACHED 13100 FT UPON XING THE DBL VOR. UPON REALIZING THE ERROR CREW IMMEDIATELY EXECUTED A MISSED APCH. DUE TO THE HIGH TERRAIN AND EXTRA ATTN TO DETAIL NEEDED WHILE TRAVELING IN AND OUT OF THESE MOUNTAINOUS ARPTS, LONGER TIME TO GET ESTABLISHED WOULD HAVE HELPED, ALONG WITH ATC DECLARING WHERE WE WERE BEING VECTORED TO, IE, OUTSIDE DBL VOR TO JOIN FINAL APCH COURSE.

Data retrieved from NASA's ASRS site as of July 2007 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.