William H.L. Mullins, 55, corporate vice president for government affairs of General Dynamics Corp. and a retired Air Force brigadier general who was a heavily decorated combat veteran of the Vietnam War, died Sept. 29 in a plane crash in Chatham, Mass.

General Dynamics is the giant St. Louis-based defense contracting concern. Gen. Mullins worked out of the company's Washington offices, situated in Crystal City in Arlington.

Gen. Mullins, who lived in Alexandria, was visiting Cape Cod for a golf tournament. The airport manager said that the general was the passenger in a restored P-51 Mustang fighter plane of World War II vintage flown by George F. Enhorning, 63, of Wolcott, Conn. Enhorning also died in the crash, the airport manager said. He added that Federal Aviation Administration officials are investigating the cause of the crash.

In 1979, Gen. Mullins retired from the Air Force and joined General Dynamics as its deputy director of legislative affairs. He became director in 1980, and was named staff vice president for legislative affairs. He had been corporate vice president since 1986.

Gen. Mullins was a native of Independence, Mo., and a 1957 graduate of the U.S. Military Academy at West Point. He also was a graduate of the Air Command and Staff College and the National War College and received a master's degree in business administration from the University of Arizona.

He spent much of his Air Force career as a fighter pilot, flying F-100s in Japan from 1959 to 1961, and F-4s from Thailand in 1967 and 1968. During his years in Thailand, he flew 146 combat missions, 116 of them over North Vietnam.

He also held a variety of Air Force staff, operations and budget posts. His last Air Force assignment was deputy director of legislative liaison in the office of the secretary of the Air Force.

His decorations included the Bronze Star, five Distinguished Flying Crosses and 13 Air Medals.

Gen. Mullins had served on the board of the National Security Industrial Association. He was a member of the National Democratic, Capitol Hill, Burning Tree and Belle Haven country clubs.

Survivors include his wife, the former Florine Lucy Magnani, of Alexandria, and two sons, Dan, an Air Force second lieutenant who is stationed in Mississippi, and Todd, of Alexandria.