The D.C. Court of Appeals, for the third time in a year, has issued guidelines to ensure further that a defendant receives adequate representation during a trial.

A three-judge panel of the appeals court, in a 33-page opinion written by Chief Justice Theodore R. Newman, ruled that if an attorney raises a questions about his own trial experience then the trial judge must closely question both the attorney and the defendant about the experience issue.

According to the opinion, no such questions were asked in the murder trial of William H. Pierce, 35, whose 1976 conviction the court overturned yesterday. Pierce was found guilty in the shooting death of Raymond Battle, 30, a few hours after the two men had argued, according to the opinion.

During the hearing two weeks before the start of the trial, Pierce's attorney, Arthur Marc Levin, asked the court to appoint a second attorney in the because Levin had only two years' trial experience, the opinion said.

"My conern here . . . is not that I don't feel competent to present the case because Levin had only two years' seriousness of the case, I frankly would like the advice of senior counsel," Levin told the trial judge, Eugene N. Hamilton, according to the opinion.

A week later, however, Levin told the judge that after consulting with other attorneys, "I am satisfied . . . that the experience I have is adequate to deal with this case at trial" and withdrew his request.

The appeals panel, with one dissent, said it was reversing the conviction because Hamilton failed to ask Pierce whether he was "satisfied with his attorney" and failed to inquire into Levin's "background and experience . . . with first-degree murder cases . . ."

In to cases decided last year the appeals court established new rules judges should follow when a defendant claims "ineffective assistance of counsel."

Fager appealed the conviction on Pierce's behalf. Pierce now is at Lorton Penitentiary, serving his sentence of 20 years to life, Fager said.