William M. Magruder, a former aircraft industry engineer, designer and project coordination who headed the Nixon administration's unsuccessful effort to launch an American SST program, died Saturday in a Winston Salem, N.C., hospital after suffering a heart attack. He was 54.

At the time of his death, Mr. Magruder was living in Winston Salem and working as an executive vice president of Piedmont Airlines.

Mr. Magruder came to Washington in June, 1970 to take the post of Director-SST development in the Department of Transportation.

For the next nine months Mr. Magruder waged a tough, if unsuccessful, fight to convince Congress that this country should join the race to produce a commercially viable supersonic transport.

The former Air Force engineer and test pilot made a controversial appearance on the Dick Cavett television talk show in March 1971, after filing a complaint with the FCC charging that the show had only presented the negative side of the SST controversy.

Following the SST defeat in Congress, Mr. Magruder was named a special consultant to the President to head the New Technologies Opportunities Group, a White House panel looking for new forms of technology that could provide jobs and economic growth for the country.

Mr. Magruder was a native of Evanston, Ill. He attended the University of Nebraska and received a B.S. degree in aeronautical engineering from the University of California. He also did graduate work in mathematics at the Ohio State University graduate school.

During his years in private industry, Mr. Magruder worked first for the Douglas Aircraft Co., now McDonald Douglas, and then for the Lockheed California Co., where he was intimately involved in that company's SST development program.

Mr. Magruder was also chief advanced design engineer for the development of Lockheed's L-1011 commercial jet transport.

During his five years with the Air Force, Mr. Magruder, a graduate of the Air Force's Experimental Test Pilot School, supervised the engineering, and evaluated the performance, of such aircraft as the B-57 and B-52 bombers, C-124 transport and the F-86 fighter.

A member of numerous test pilots' and aircraft industry groups and associations, he was the past president of the Society of Experimental Test Pilots.

Mr. Magruder is survived by his wife, Barbara, of the home; a son, William M. Magruder, of New York City; a daugther, Nancy, of the home; and a brother, Bruar, of Long Beach, Calif.