Theodore Edward Hall III, 33, an architect and a sailing enthusiast, his wife, Catherine Rita Hall, also 33 and a sailing enthusiast and an employe of a boat owners association, and Theodore Ewing Hall IV, their 5-month-old son, were killed Sunday when the private plane in which they were passengers crashed moments after taking off from Woodbridge Airport.

Herbert Ewing, 60, the pilot and Mr. Hall's stepfather, and his wife, Evelyn Longstreet Hall Ewing, 58, Mr. Hall's mother, also were killed. Officials of the National Transportation Safety Board said the crash was still under investigation.

Mr. Hall was born in Redbank, N.J. He graduated from Texas Technological College at Lubbock with a degree in architecture. He moved to Maryland about 1978 and went to work for the Centex Construction Co. at Fort Meade. He later worked for Henningson, Durham & Richardson International Inc. in Alexandria. For the past year, he had been with Settles Associates Inc. in Arlington. He was a member of the American Institute of Architects.

Mr. and Mrs. Hall and their son lived in Alexandria.

From August 1981, to May 1982, Mr. Hall and his wife, the former Catherine Rita Powell, cruised from Maine to the Caribbean aboard a 40-foot sloop.

At the time of her death, Mrs. Hall was the associate director of consumer affairs of the Boat Owners Association of The United States. She had worked for the association since 1982 and before that had written free-lance articles about sailing for general interest magazines.

She was born in Washington and raised in Bethesda. She received an associate degree in general education from Montgomery College and graduated from the University of Maryland in 1980. She worked for the GEICO insurance company from 1974 to 1981 and had been an automobile claims adjuster.

Mr. and Mrs. Ewing were residents of Holmdel, N.J. Mr. Ewing was an engineer with a tugboat company. Mrs. Ewing was a first grade teacher in Wall Township, N.J.

Mr. Hall's survivors include his father, Theodore E. Hall Jr. of Oceanport, N.J., and two brothers, Thomas L. and Douglas M., both of Bricktown, N.J.

Mrs. Hall's survivors include her mother, Rita Powell of Bethesda; a sister, Maureen, also of Bethesda, and two brothers, Paul, of Bethesda, and James, of Silver Spring, and one grandmother, Catherine Fitzgerald of Silver Hill, Md.