Commuter light transport altitude deviation excursion from clearance altitude on approach into cwa.

Attributes
ACN	193789
Time
Date	199110
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cwa
State Reference	WI
Altitude	msl bound lower : 3800 msl bound upper : 4000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp
Operator	common carrier : air carrier
Make Model Name	Light Transport
Flight Phase	cruise other descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 110 flight time total : 4000 flight time type : 2300
ASRS Report	193789
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Proceeding to cwa airport, ZMP cleared us to the danci OM via the 17 DME arc, for the ILS runway 8 approach. The arc provides a transition to the approach, authorizing 3000 ft, no pt. Once established on the arc, we called out of 4000 ft for 3000 ft. I assumed a clearance for the arc included the transition with the descent to 3000 ft. We would be unable to fly the approach if we reached the OM at 4000 ft, we would be too high. Center told us we were not cleared for the approach, to return and report level at 4000 ft. We had gone down to 3800 ft, we immediately leveled at 4000 ft. The controller then seemed confused as to the arc clearance itself. I am aware that an approach clearance must precipitate any descent, but I assumed a clearance for a DME arc was akin to being cleared for a published transition to an approach, including descent to the applicable altitude.

Original NASA ASRS Text

Title: COMMUTER LTT ALTDEV EXCURSION FROM CLRNC ALT ON APCH INTO CWA.

Narrative: PROCEEDING TO CWA ARPT, ZMP CLRED US TO THE DANCI OM VIA THE 17 DME ARC, FOR THE ILS RWY 8 APCH. THE ARC PROVIDES A TRANSITION TO THE APCH, AUTHORIZING 3000 FT, NO PT. ONCE ESTABLISHED ON THE ARC, WE CALLED OUT OF 4000 FT FOR 3000 FT. I ASSUMED A CLRNC FOR THE ARC INCLUDED THE TRANSITION WITH THE DSCNT TO 3000 FT. WE WOULD BE UNABLE TO FLY THE APCH IF WE REACHED THE OM AT 4000 FT, WE WOULD BE TOO HIGH. CENTER TOLD US WE WERE NOT CLRED FOR THE APCH, TO RETURN AND RPT LEVEL AT 4000 FT. WE HAD GONE DOWN TO 3800 FT, WE IMMEDIATELY LEVELED AT 4000 FT. THE CTLR THEN SEEMED CONFUSED AS TO THE ARC CLRNC ITSELF. I AM AWARE THAT AN APCH CLRNC MUST PRECIPITATE ANY DSCNT, BUT I ASSUMED A CLRNC FOR A DME ARC WAS AKIN TO BEING CLRED FOR A PUBLISHED TRANSITION TO AN APCH, INCLUDING DSCNT TO THE APPLICABLE ALT.

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.