Narrative:

We were inbound to the kalispell VOR on V448 from spokane when we received descent clearance to 13000', and then 12000'. Shortly after we were cleared to 12000'. ATC instructed us that we were 'cleared to the smith lake NDB via the killy transition, cleared approach.' we were established inbound on V448 outside killy intersection when we received the instructions. We descended to 12000', and after killy intersection, we descended to 8000'. At smith lake NDB we turned outbnd to intercept the localizer and started to descend to 7700', in order to set-up for the procedure turn. Approximately 30 seconds later ATC asked us our altitude and we replied, '8000'.' he told us that we were supposed to maintain 12000'. We said that we thought we were cleared for the approach. ATC said, 'negative, fly current heading.' 30 seconds later he told us to climb to 10000'. Shortly afterward we were cleared back to the NDB to hold. About 3 mi prior to reaching the NDB, ATC cleared us for the approach and we proceeded to do the approach. Factors that may have contributed to the misunderstanding of the clearance could have been that when inbound on the arwy to kalispell VOR, ATC told us that it would be in our best interest to reduce our airspeed since there were already 2 other aircraft involved in the approach. I anticipated either holding at the NDB or continuing the approach, and when ATC cleared us to the NDB with no holding instructions my mind clicked into the approach mode. Complacency was probably a factor also since I have flown this particular approach many times under similar situations. Another factor could have been this pilot's inability to get a good night's rest since I slept for only 3 1/2 hours the night before, as most air carrier pilots can attest happens on occasion. An extra measure of vigilance must be maintained when complacency sets in.

Related reports:

Google
 

Original NASA ASRS Text

Title: FLT CREW OF LTT MISINTERPRETED THEIR CLRNC, DESCENDED ON TRANSITION, CORRECTED BY ZLC CTLR.

Narrative: WE WERE INBND TO THE KALISPELL VOR ON V448 FROM SPOKANE WHEN WE RECEIVED DSCNT CLRNC TO 13000', AND THEN 12000'. SHORTLY AFTER WE WERE CLRED TO 12000'. ATC INSTRUCTED US THAT WE WERE 'CLRED TO THE SMITH LAKE NDB VIA THE KILLY TRANSITION, CLRED APCH.' WE WERE ESTABLISHED INBND ON V448 OUTSIDE KILLY INTXN WHEN WE RECEIVED THE INSTRUCTIONS. WE DSNDED TO 12000', AND AFTER KILLY INTXN, WE DSNDED TO 8000'. AT SMITH LAKE NDB WE TURNED OUTBND TO INTERCEPT THE LOC AND STARTED TO DSND TO 7700', IN ORDER TO SET-UP FOR THE PROC TURN. APPROX 30 SECS LATER ATC ASKED US OUR ALT AND WE REPLIED, '8000'.' HE TOLD US THAT WE WERE SUPPOSED TO MAINTAIN 12000'. WE SAID THAT WE THOUGHT WE WERE CLRED FOR THE APCH. ATC SAID, 'NEGATIVE, FLY CURRENT HDG.' 30 SECS LATER HE TOLD US TO CLB TO 10000'. SHORTLY AFTERWARD WE WERE CLRED BACK TO THE NDB TO HOLD. ABOUT 3 MI PRIOR TO REACHING THE NDB, ATC CLRED US FOR THE APCH AND WE PROCEEDED TO DO THE APCH. FACTORS THAT MAY HAVE CONTRIBUTED TO THE MISUNDERSTANDING OF THE CLRNC COULD HAVE BEEN THAT WHEN INBND ON THE ARWY TO KALISPELL VOR, ATC TOLD US THAT IT WOULD BE IN OUR BEST INTEREST TO REDUCE OUR AIRSPD SINCE THERE WERE ALREADY 2 OTHER ACFT INVOLVED IN THE APCH. I ANTICIPATED EITHER HOLDING AT THE NDB OR CONTINUING THE APCH, AND WHEN ATC CLRED US TO THE NDB WITH NO HOLDING INSTRUCTIONS MY MIND CLICKED INTO THE APCH MODE. COMPLACENCY WAS PROBABLY A FACTOR ALSO SINCE I HAVE FLOWN THIS PARTICULAR APCH MANY TIMES UNDER SIMILAR SITUATIONS. ANOTHER FACTOR COULD HAVE BEEN THIS PLT'S INABILITY TO GET A GOOD NIGHT'S REST SINCE I SLEPT FOR ONLY 3 1/2 HRS THE NIGHT BEFORE, AS MOST ACR PLTS CAN ATTEST HAPPENS ON OCCASION. AN EXTRA MEASURE OF VIGILANCE MUST BE MAINTAINED WHEN COMPLACENCY SETS IN.

Data retrieved from NASA's ASRS site as of August 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.