Fairchild Industries Inc. has promoted Rodney L. Woodworth to president and chief operating officer of the firm's commercial/industrial group. Woodworth, formerly president of the group's industrial and building products division, has been with Fairchild since it acquired VSI Corp. in 1980. He succeeds Frank S. Marra , who will be a special assistant to the group's chief executive, Executive Vice President George S. Attridge.

Crown Central Petroleum Corp. in Baltimore has elected Victor G. Oberschall vice president for supply and transportation. Oberschall, formerly assistant secretary for the corporation and general manager for transportation, petrochemicals and feedstocks, will continue to work in the firm's Bellaire, Tex., office.

Diagnon Corp., the Laurel-based manufacturer of medical diagnostic equipment, has elected W. Wallace McDowell Jr. and J. Thomas August directors of the one-year-old company. McDowell is chairman of the Prospect Group Inc., a New York-based venture capital firm. August, a founder and the chief scientific advisor of Diagnon, is director of the Department of Pharmacology and Experimental Therapeutics at the Johns Hopkins University School of Medicine. Diagnon also announced the resignation of Director James C. Cooke , executive vice president of Laidlaw, Adams & Peck Inc., who cited commitments that preclude his participation in the firm's affairs.

Occidental Petroleum Corp. has appointed Edward Crotty general counsel of its Washington-based subsidiary, Occidental International Corp. Crotty was formerly deputy assistant general counsel for the Department of the Air Force.