Frederic L. Royer, 62, retired official of the old Post Office Department and a director of the U.S. Postal Service Federal Credit Union for 18 years, died of a respiratory ailment Wednesday at the National Institutes of Health.

He retired in 1971 as director of the department personnel division at Post Office headquarters here. He had joined the department as a placement officer in 1956 and later was chief of the employee developement branch.

The department became the Postal Service in July 1971. Three years after he retired, Mr. Royer returned as a special consultant to the postmaster general.

He was appointed to the credit union board of directors in 1961 and served as president of the board from March 1977, until last March.

Mr. Royer was born in Salamanca, N.Y. After serving with the Army in Europe in World War ii, he came here and worked as a civilian with the Army Corps of Engineers until transferring to the Post Office Department. a

He is survived by his wife, Edna H., of the home in Silver Spring; a daughter Carol Costello of Fairfax; a son, F. David, of La Pine, Ore.; two sisters, Elizabeth Royer of Cleveland, and Helen Royer of Phoenix, Ariz., and four grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to Grace Episcopal Church in Silver Spring.