Frank R. Mahan, 49 a senior electronics engineer at the Johns Hopkins Applied Physics Laboratory, died Thursday at the University of Maryland Hospital in Baltimore after an apparent heart attack.

A regular staff member at the laboratory since 1952, he was responsible for the application of mini-and micro-computer technology in the design of several advanced electronic systems.

Mr. Mahan had worked on missile guidance and digital computers and was considered an authority on programming computers as intelligent system elements.

Born in Warren, Ohio, he served in the U.S. Marines after World War II, and was assigned as a technician to the Johs Hopkins Laboratory. There he participated in the early testing of the first ramjet-propelled missile, the TALOS.

Mr. Mahan was on other duty with the Marine Corps during the Korean conflict and then returned to the laboratory as a civilian.

He had received an associate in arts degree from Montgomery College and took advanced work in electronics and digital logic at the University of Maryland and University of Michigan. He lived in Columbia, Md.

He is survived by a daughter, Kathleen Blankenship, of Alexandria; a son, Frank p., of Illinois, and a brother, Richard, of Warren.