Alfred S. Trask, 76, a retired electrical engineer long active in area civic affairs, died in his sleep Monday at his home in Washington.

Born in Minneapolis, he was a graduate of the University of Minnesota. He came here in 1931 to work as an electrical engineer for the U.S. Patent Office.

Mr. Trask earned a law degree from Georgia Washington University in 1934 and became a patent examiner, retiring from the Patent Office in 1967.

He was active in the American University Park Citizens Association, of which he was a past president. He also was former chairman of the transportation committee of the Federation of Citizens Associations and was a current delegate to the federation.

As an official of these organizations, Mr. Trask testified frequently at congressional committee hearings and wrote many letters to the editor concerning community affairs.

He was credited with helping plan for the publicly owned mass transportation system here and in the establishment of the C&O Canal as a national park.

He is survived by his wife, Eleanor, of the home; two sons, David, of Raleigh, N.C., and Richard, of Frostburg, Md.; a daughter, Marian Lapp, of Washingfton, and nine grandchildren.

The family suggests that expressions of sympathy may be in the form of contributions to St. Columbia's Episcopal Church Memorial Fund.