Hugh Allen Overby, 70, a retired Federal Aviation Agency electronics engineer, died of congestive heart failure Sunday at Northern Virginia Doctors Hospital. He lived in Alexandria.

Mr. Overby joined the old Civil Aeronautics Authority as an electronics engineer in 1939. From 1955 to 1960, he worked with the State Department in Panama, then returned here to the old Federal Aviation Agency where he worked until retiring in 1966.

Mr. Overby was a member of the Fourth Presbyterian Church in Bethesda. He was a member of the Lawyer's Club Prayer Group here and a past member of the FAA Prayer Group.

Mr. Overby was a member of the Institute of Radio Engineers. He was a member of the Robert E. Lee Chapter of sons of Confederate Veterans. He was a Mason and member of Kena temple. He also had been a member of the Order of the Eastern Star.

Mr. Overby was a native of Wister, Okla., and served in the Navy from 1931 to 1937. He was a 1951 graduate of Canal Zone Junior College and attended the University of Panama.

Survivors include his wife of 36 years, the former Mirial Lillian Todd, of Alexandria, and two sisters, Ina Le Flore and Irene McCurtain, both of Oklahoma.