Armand J. Thieblot, 74, an internationally known aircraft-designer, died of cancer Jan. 6 at Washington County Hospital in Hagerstown.

Born in Paris, he had designed aircraft in Europe before coming to this country in 1928. He was a designer for Columbia Air Liners and then was with Fokker Aircraft Corp. before joining Fairchild Aircraft in 1933.

He was chief structural engineer at the firm in Hagerstown and became chief engineer in 1937. He was involved in developing a number of military aircraft during World War 11.

Mr. Thieblot formed his own consulting firm, the A.J. Thielblot Aircraft Engineering Co., in 1951. Five years later it became part of the Vitro Corp. of America.

He remained with Vitro as a director and continued as president of the Thieblot Aircraft Division until 1959, whe he returned to Fairchild as director of engineering.

A year later, he formed the Thieblot and Associates Corp. and subsequently the Vulcana Corp., an engineering firm with which he was affiliated until his retirement in 1966.

Mr. Thieblot then taught for several years at the Hagerstown Junior College. He was the author of numerous technical articles and belonged to many technical organizations.

He is survived by his wife, Eva Mancini Thieblot, of the home in Hagerstown; two sons, Robert J. and Armand J. Jr., both of Baltimore; a sister, Juliette Crept, of Paris, and one grandchild.