Paul R. Boucher, a 40-year-old official of the Small Business Administration, was killed in a bizarre accident on the Fourth of July, 1982. A model airplane, out of control, smashed into his chest as he stood talking to another man in a field in Loudoun County.

Yesterday, Ginette Boucher, his widow, agreed to accept $165,000 as settlement of her $2.5 million lawsuit in Fairfax County Circuit Court against James S. Benson, the man who had been flying the gasoline-powered plane using a remote radio control box.

Paul Boucher, a lawyer for a number of government agencies beginning in 1972, was SBA's inspector general. Appointed to the SBA job by President Jimmy Carter, he survived a purge of federal inspectors general with the advent of the Reagan administration.

Like Benson, he was a model plane hobbyist, and had gone to the field to fly his own model airplane when the accident happened.

The settlement of his widow's suit was announced after lunch yesterday to a jury that had already begun to hear testimony in the case that was to be marked by expert witnesses and discussions of aerodynamics, safety records and preflight check procedures similar to those for full-size, general aviation planes.

The model plane -- in pieces -- that struck Boucher rested on the table in front of Ginette Boucher's attorneys. It is an 8 pound Aeromaster Too biplane with a 6-foot wingspan that was used for stunt flying.

Ginette Boucher, 40, who lives with her son, 16, and daughter, 12, in Vienna, said she was satisfied with the settlement. One of her attorneys, Robert Lewis, said: "165,000 is a long way from zero, which is what a lot of people thought this suit was worth."

After the jury was dismissed, Ginette Boucher spoke briefly with Benson, saying, "I never had any animosity toward you. If the situation had been reversed, I'm sure your wife would have done the same thing."

It was the first time the two had spoken since Benson went to Loudoun Memorial Hospital, where Boucher died, on the day of the accident.

Benson, 45, an employe of the Food and Drug Administration who lives near Tysons Corner, told a reporter, "The whole thing has been very difficult for me. I've been very concerned for Mrs. Boucher . . . . I'm relieved that it's over."

An attorney for Benson would not say whether the settlement is covered by insurance.

Benson, an enthusiastic model airplane hobbyist who had flown model planes weekly for six years at the time of the accident, said he has not done so since.

Why his model plane went out of control was in dispute.

It had crashed about two months before the accident that killed Boucher, according to yesterday's court proceedings, and Benson had then repaired its horizontal stabilizer with glue.

Either shortly before the accident or as a result of it, the stabilizer, which forms part of the tail assembly, ripped off, according to testimony. Lewis, Ginette Boucher's attorney, contended that it ripped off in flight, causing the plane to go out of control.

"The repair he did to the broken stabilizer was inadequate and negligent," Lewis told the jury in his opening argument. "Paul Boucher was killed because of the negligence of this defendant."

Robert Ellis, Benson's attorney, said the repair was adequate, and said Benson had flown the plane three or four times after the repair, including once in a stunt-flying contest, without problems.

"The evidence will show that this was a freak accident," Ellis said. He said "crack-ups" in model airplane flying were "the rule rather than the exception."