Narrative:

Unable to maintain VFR at an assigned minimum altitude, I continued a descent in front of the path of a B737 according to ATC. ATC did not provide detail of miss distance or if any action was required by the B737. I did not observe the B737. While en route, I was on flight following VFR at 10500 ft. At 40 NM wsw of isz, I was in contact with cincinnati approach who indicated 'altitude your discretion' and I began a descent. Although luk reported visibility of 5 NM and clear, there were many clouds in the area to approximately 8000 ft. I selected what appeared to be a large hole along my path of flight and began to steepen my descent. At about this time, I was contacted to maintain altitude at or above 4500 ft which I acknowledged. Upon approaching 4500 ft, I realized clouds continued well below this level and it would be impossible to level off and maintain VFR. I contacted ATC while continuing descent (150 KIAS, approximately 1200 FPM). ATC indicated that they would appreciate it if I would inform them sooner next time, adding that I had descended in front of the flight path of a B737 on approach. No additional information about the miss was conveyed. At that time radar services were terminated. I failed to obtain WX information about cloud ceilings before beginning descent. I mistakenly assumed ATC's altitude request implied ceilings and VFR conditions at that altitude. I made a poor selection of descent area, resulting in aggressive descent profile, and accepting altitude minimum without knowing if it could be complied with.

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Original NASA ASRS Text

Title: LOW-TIME C172RG PLT ON VFR FLT FOLLOWING CAUSED AIRBORNE CONFLICTION WITH A B737 ON APCH TO CVG.

Narrative: UNABLE TO MAINTAIN VFR AT AN ASSIGNED MINIMUM ALT, I CONTINUED A DSCNT IN FRONT OF THE PATH OF A B737 ACCORDING TO ATC. ATC DID NOT PROVIDE DETAIL OF MISS DISTANCE OR IF ANY ACTION WAS REQUIRED BY THE B737. I DID NOT OBSERVE THE B737. WHILE ENRTE, I WAS ON FLT FOLLOWING VFR AT 10500 FT. AT 40 NM WSW OF ISZ, I WAS IN CONTACT WITH CINCINNATI APCH WHO INDICATED 'ALT YOUR DISCRETION' AND I BEGAN A DSCNT. ALTHOUGH LUK RPTED VISIBILITY OF 5 NM AND CLR, THERE WERE MANY CLOUDS IN THE AREA TO APPROX 8000 FT. I SELECTED WHAT APPEARED TO BE A LARGE HOLE ALONG MY PATH OF FLT AND BEGAN TO STEEPEN MY DSCNT. AT ABOUT THIS TIME, I WAS CONTACTED TO MAINTAIN ALT AT OR ABOVE 4500 FT WHICH I ACKNOWLEDGED. UPON APCHING 4500 FT, I REALIZED CLOUDS CONTINUED WELL BELOW THIS LEVEL AND IT WOULD BE IMPOSSIBLE TO LEVEL OFF AND MAINTAIN VFR. I CONTACTED ATC WHILE CONTINUING DSCNT (150 KIAS, APPROX 1200 FPM). ATC INDICATED THAT THEY WOULD APPRECIATE IT IF I WOULD INFORM THEM SOONER NEXT TIME, ADDING THAT I HAD DSNDED IN FRONT OF THE FLT PATH OF A B737 ON APCH. NO ADDITIONAL INFO ABOUT THE MISS WAS CONVEYED. AT THAT TIME RADAR SVCS WERE TERMINATED. I FAILED TO OBTAIN WX INFO ABOUT CLOUD CEILINGS BEFORE BEGINNING DSCNT. I MISTAKENLY ASSUMED ATC'S ALT REQUEST IMPLIED CEILINGS AND VFR CONDITIONS AT THAT ALT. I MADE A POOR SELECTION OF DSCNT AREA, RESULTING IN AGGRESSIVE DSCNT PROFILE, AND ACCEPTING ALT MINIMUM WITHOUT KNOWING IF IT COULD BE COMPLIED WITH.

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.