Narrative:

We wanted to make a VFR flight from oakland to sacramento mather, due to a passenger's discomfort with IMC. We had checked WX 3 times before departure, and mhr consistently reported 5 mi and clear. Approaching sacramento airspace from the southwest, we obtained mather ATIS, which was again 5 mi and clear. We were receiving flight following from sacramento approach, and when we were 4 mi from the field, sacramento approach advised that mather had just issued a special 1/2 mi visibility, ceiling 100 ft with fog. Quite a surprise! We requested and were cleared for the ILS to runway 22L. As we approached the airport, we could clearly see runway 22L, but the edge of the fog bank had enveloped the tower. We advised approach that the runway was VFR, and we'd like to cancel IFR, and just turn base and land. Approach replied that he didn't think we could cancel IFR, because we didn't have 1 mi of visibility. We advised that we had at least 5 mi of flight visibility, and didn't that govern? Approach then handed us off to the tower. Tower cleared us to land, which we did in VFR conditions. After checking with my instructor, I realize I didn't handle this properly. With the tower reporting IFR and less than 1 mi visibility, I had no option besides an instrument approach. I focused on the VFR runway and forgot that reported visibility controled the requirement for a clearance.

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Original NASA ASRS Text

Title: A GA INST RATED PLT BECOMES CONFUSED ABOUT THE NEED TO USE AN INST APCH WHEN THE TWR RPTS IFR AND YET HE CAN SEE THE RWY.

Narrative: WE WANTED TO MAKE A VFR FLT FROM OAKLAND TO SACRAMENTO MATHER, DUE TO A PAX'S DISCOMFORT WITH IMC. WE HAD CHKED WX 3 TIMES BEFORE DEP, AND MHR CONSISTENTLY RPTED 5 MI AND CLR. APCHING SACRAMENTO AIRSPACE FROM THE SW, WE OBTAINED MATHER ATIS, WHICH WAS AGAIN 5 MI AND CLR. WE WERE RECEIVING FLT FOLLOWING FROM SACRAMENTO APCH, AND WHEN WE WERE 4 MI FROM THE FIELD, SACRAMENTO APCH ADVISED THAT MATHER HAD JUST ISSUED A SPECIAL 1/2 MI VISIBILITY, CEILING 100 FT WITH FOG. QUITE A SURPRISE! WE REQUESTED AND WERE CLRED FOR THE ILS TO RWY 22L. AS WE APCHED THE ARPT, WE COULD CLRLY SEE RWY 22L, BUT THE EDGE OF THE FOG BANK HAD ENVELOPED THE TWR. WE ADVISED APCH THAT THE RWY WAS VFR, AND WE'D LIKE TO CANCEL IFR, AND JUST TURN BASE AND LAND. APCH REPLIED THAT HE DIDN'T THINK WE COULD CANCEL IFR, BECAUSE WE DIDN'T HAVE 1 MI OF VISIBILITY. WE ADVISED THAT WE HAD AT LEAST 5 MI OF FLT VISIBILITY, AND DIDN'T THAT GOVERN? APCH THEN HANDED US OFF TO THE TWR. TWR CLRED US TO LAND, WHICH WE DID IN VFR CONDITIONS. AFTER CHKING WITH MY INSTRUCTOR, I REALIZE I DIDN'T HANDLE THIS PROPERLY. WITH THE TWR RPTING IFR AND LESS THAN 1 MI VISIBILITY, I HAD NO OPTION BESIDES AN INST APCH. I FOCUSED ON THE VFR RWY AND FORGOT THAT RPTED VISIBILITY CTLED THE REQUIREMENT FOR A CLRNC.

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.