Narrative:

I was on an IFR flight plan from las vegas mc carran to carson city municipal airport at FL200. Approximately 75 NM southeast of carson city I entered the clouds and was in and out of VMC. At approximately 45 NM from carson I requested a descent into carson city and was assigned 16000'. At 17500' in VMC I cancelled IFR and proceeded a VFR descent in a large break in the cloud cover. Upon reaching 13000' VFR I saw we could not continue under the cloud deck VFR and initiated a climb back on top. (Tops in the area were 13000-20000' layered.) at 14500' I called ZOA back and advised them I could not continue the flight under the deck of clouds in VFR conditions and requested a vector to carson city. ZOA advised a 10 degree correction to the right and an altitude of 14000'. We proceeded in VFR conditions at 14000' until making visibility contact with the carson city airport, approximately 25 NM southeast. I advised ZOA of the visibility contact of the airport and was proceeding under my own navigation. I began the descent to clear a layer of clouds over the carson valley when ZOA called me back to see if I was planning to again cancel my IFR. Because of my descent, I was not receiving ZOA clearly and changed to the frequency 128.8 (the local ZOA frequency for the carson area) and advised them I was proceeding VFR to carson and had already cancelled my IFR flight plan with ZOA on 125.75. It was my understanding I was still VFR and never established another IFR clearance. The entire flight was made in VFR conditions after the initial cancellation of the IFR flight plan. Apparently it was ZOA's understanding that they had given me a hard altitude and was back to IFR and that my descent into carson city broke the assigned altitude of 14000'.

Related reports:

Google
 

Original NASA ASRS Text

Title: PLT BEGAN DESCENT WITHOUT CLRNC THINKING HE WAS VFR.

Narrative: I WAS ON AN IFR FLT PLAN FROM LAS VEGAS MC CARRAN TO CARSON CITY MUNICIPAL ARPT AT FL200. APPROX 75 NM SE OF CARSON CITY I ENTERED THE CLOUDS AND WAS IN AND OUT OF VMC. AT APPROX 45 NM FROM CARSON I REQUESTED A DSCNT INTO CARSON CITY AND WAS ASSIGNED 16000'. AT 17500' IN VMC I CANCELLED IFR AND PROCEEDED A VFR DSCNT IN A LARGE BREAK IN THE CLOUD COVER. UPON REACHING 13000' VFR I SAW WE COULD NOT CONTINUE UNDER THE CLOUD DECK VFR AND INITIATED A CLB BACK ON TOP. (TOPS IN THE AREA WERE 13000-20000' LAYERED.) AT 14500' I CALLED ZOA BACK AND ADVISED THEM I COULD NOT CONTINUE THE FLT UNDER THE DECK OF CLOUDS IN VFR CONDITIONS AND REQUESTED A VECTOR TO CARSON CITY. ZOA ADVISED A 10 DEG CORRECTION TO THE RIGHT AND AN ALT OF 14000'. WE PROCEEDED IN VFR CONDITIONS AT 14000' UNTIL MAKING VIS CONTACT WITH THE CARSON CITY ARPT, APPROX 25 NM SE. I ADVISED ZOA OF THE VIS CONTACT OF THE ARPT AND WAS PROCEEDING UNDER MY OWN NAV. I BEGAN THE DSCNT TO CLR A LAYER OF CLOUDS OVER THE CARSON VALLEY WHEN ZOA CALLED ME BACK TO SEE IF I WAS PLANNING TO AGAIN CANCEL MY IFR. BECAUSE OF MY DSCNT, I WAS NOT RECEIVING ZOA CLEARLY AND CHANGED TO THE FREQ 128.8 (THE LCL ZOA FREQ FOR THE CARSON AREA) AND ADVISED THEM I WAS PROCEEDING VFR TO CARSON AND HAD ALREADY CANCELLED MY IFR FLT PLAN WITH ZOA ON 125.75. IT WAS MY UNDERSTANDING I WAS STILL VFR AND NEVER ESTABLISHED ANOTHER IFR CLRNC. THE ENTIRE FLT WAS MADE IN VFR CONDITIONS AFTER THE INITIAL CANCELLATION OF THE IFR FLT PLAN. APPARENTLY IT WAS ZOA'S UNDERSTANDING THAT THEY HAD GIVEN ME A HARD ALT AND WAS BACK TO IFR AND THAT MY DSCNT INTO CARSON CITY BROKE THE ASSIGNED ALT OF 14000'.

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.