Narrative:

My flight was planned so as to avoid in-flight icing by flying a lower altitude (5;000 ft MSL) along vxx instead of a direct route at the flight planned (9;000 ft MSL) cruise altitude. I was VMC the entire flight and flew through two areas of light snow as I progressed toward the VOR. After passing the VOR I began to accrue clear and mixed ice in VMC conditions; I later concluded that I had encountered isolated areas of freezing rain; and requested 4;000 ft. Approximately 20 miles east of the VOR enroute to the next VOR on vxx; I informed center that a descent to published MEA (3;200 ft) was required to escape in-flight icing. Center advised us that their minimum enroute IFR altitude was 3;700 ft. I descended to 3;200 ft and was able to escape icing for a brief time. Center informed us that this altitude (3;200 ft) required a declaration of emergency on their behalf due to the conflict in altitude minimums and that I was now an emergency aircraft. Shortly after this time I was switched to approach control while continuing along vxx at 3;200 ft MSL. Approach began providing radar vectors to runway xxl and a descent to 3;000 ft MSL. I continued to accrue occasional clear ice the remainder of the flight. I requested as little vectoring as possible and was told I was number two for xxl. I later asked for a direct vector to the airport and was given this request and cleared for a visual approach to xxl. I made a faster than normal approach and a safe landing was made.

Google
 

Original NASA ASRS Text

Title: IFR General Aviation pilot described an icing event when descent to lower that ATC authorized altitude was required resulting in an ATC declared emergency declaration.

Narrative: My flight was planned so as to avoid in-flight icing by flying a lower altitude (5;000 FT MSL) along VXX instead of a direct route at the flight planned (9;000 FT MSL) cruise altitude. I was VMC the entire flight and flew through two areas of light snow as I progressed toward the VOR. After passing the VOR I began to accrue clear and mixed ice in VMC conditions; I later concluded that I had encountered isolated areas of freezing rain; and requested 4;000 FT. Approximately 20 miles east of the VOR enroute to the next VOR on VXX; I informed Center that a descent to published MEA (3;200 FT) was required to escape in-flight icing. Center advised us that their minimum enroute IFR altitude was 3;700 FT. I descended to 3;200 FT and was able to escape icing for a brief time. Center informed us that this altitude (3;200 FT) required a declaration of emergency on their behalf due to the conflict in altitude minimums and that I was now an emergency aircraft. Shortly after this time I was switched to Approach Control while continuing along VXX at 3;200 FT MSL. Approach began providing RADAR vectors to Runway XXL and a descent to 3;000 FT MSL. I continued to accrue occasional clear ice the remainder of the flight. I requested as little vectoring as possible and was told I was number two for XXL. I later asked for a direct vector to the airport and was given this request and cleared for a visual approach to XXL. I made a faster than normal approach and a safe landing was made.

Data retrieved from NASA's ASRS site as of April 2012 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.