The U.S. Court of Appeals here ruled yesterday that the FBI acted improperly four years ago when it fired a homosexual mail sorter without giving him a hearing.

The ruling by a three-judge panel reinstates a suit brought by mail clerk Donald Ashton, who is challenging the right of the FBI to fire homosexuals working in its non-investigatory sections.

Ashton contends he was fired solely because of his sexual preference; the FBI contends he wasn't fired at all, but "voluntarily resigned" after being confronted with the bureau's knowledge of his homosexuality.

The court panel made it clear that it was not dealing with the issue of whether he was fired or resigned, nor with the issue of whether he could have been fired solely because of his homosexuality.

It said, instead, that those issues should be confronted at a hearing such as the one Ashton should have received before he was dismissed.

The court, in an opinion written by U.S. Circuit Judge Carl McGowan, noted, however, that it felt Ashton "could properly be dismissed only for failing to perform his duties satisfactorily and without prejudice to the FBI's achievement of its law-enforcement mission."

The court noted also that the bureau "seems preoccupied with what might well be thought [to be] the private lives of its employes," because of other personnel regulations it has promulgated concerning such items as "grooming and demeanor, outside employment or business ventures, payments of debts, and marriages, divorces, annulments, births and name changes."

Ashton had worked for the FBI from Oct. 3 1973, until Jan. 10, 1975, when he was summoned to the office of a superior. There, according to the undisputed record of the suit, he was told that the Navy had forwarded a report to the FBI that one of its employes had admitted engaging in homosexual acts with an FBI mail clerk he knew only as "Don."

Ashton denied the specifics of the alleged homosexual encounter, but told his superiors he remembered the incident and had been a homosexual for the previous three years. He added, however, that no one at the FBI knew about it.

What happened in conversations over the next hour or so is in dispute, but both sides agree that Ashton signed a hand-written resignation letter, effective immediately.

A lower court judge dismissed Ashton's suit because he said Ashton had not shown he had any "property interest" in the job and therefore he was not due a hearing.

Although the FBI argued to the appellate court that it had a solid policy against allowing known homosexuals to work for the bureau, the court said yesterday that FBI director William Webster recently indicated that might not always be the case.

In addition, the court stated, there is no written policy within the FBI that says homosexuality alone is cause for automatic dismissal from a bureau job.

Even if the bureau had such a policy, the court continued, it "stands in sharp contrast" to policies in other federal agencies and the military.

McGowan, joined by U.S. Circuit Judges Harold H. Leventhal and J. Skelly Wright, said the FBI handbook distributed to Ashton and other employes said they "may assume your position is secure, if you continue to do satisfactory work."

That, according to the appellate judges, gave Ashton a "property right" to his job and made him eligible for a full hearing before he could be dismissed.