An inmate who flees a jail can be acquitted of escape charges if he can prove the reason he escaped was because of bad conditions there instead of merely to seek freedom, the U.S. Court of Appeals here ruled yesterday.

In a 2-to-1 ruling written by U.S. Circuit Chief Judge J. Skelly Wright, the appeals panel ordered new trials under those guidelines for four men who escaped from the new D.C. jail on Aug. 26, 1976.

The panel said the judge in the original trial had unnecessarily told the jury not to consider certain arguments by the defendants concerning alleged poor conditions at the city jail.

The dissenting appellate judge, Malcolm R. Wilkey, issued a blistering, long and sarcastic dissent in which he said his two colleagues "are apparently prepared to labor mightily to exculpate these defendants" and that the application of the ruling "would make a mockery" out of federal escape laws.

The trial judge had allowed the defendants to present evidence that there had been frequent fires at the new jail that were allowed to burn themselves out, poor ventilation, threats and beatings by guards, and alleged denial of medical treatment for one of the inmates.

Jail officials largely denied the accusations during the trial.

Although the trial judge, U.S. District Judge Oliver Gasch, allowed the evidence to be presented to the jury, he instructed the jurors at the end of the case that the conditions at the jail could not be used as a justification for an escape. He also told the jury they could not consider a defense of "duress" because none of the defendants tried to voluntarily turn themselves in to authorities after actually leaving the alleged bad conditions.

The appeals court said in its ruling that, under the law, the word "escape - like many other legal terms - is not self-defining" and a judge has to carefully instruct a jury about the essential elements of the crime.

The appeals court concluded that an "escape" occurs when a defendant leaves custody voluntarily without permission and with an intent to avoid confinement.

"If a prisoner offers evidence to show that he left confinement only to avoid conditions that are not normal aspects of 'confinement' - such as beating in reprisal for testimony in a trial, failure to provide essential medical care, or homosexual attacks - the intent element of the crime of escape may not be satisfied," Wright said in a footnote.

In refusing to let the jury consider the prison conditions, Wright added, the trial judge had omitted evidence that was relevant to an essential element of the crime.

He said the trial judge apparently had based his exclusion of the evidence on cases "in which courts, moved by fears of undermining prison discipline or encouraging mass escapes, have hesitated to allow juries to consider such (evidence) unless various rigorous conditions have been satisfied."

Wright said juries are accustomed to determing whether or not a defendant had a criminal intent to commit a crime, "and we see nothing in the context of prosecutions for escape that requires the court to risk denying the defendants a fair trial by denying the jury its normal function."

He said allowing the jury to perform its accustomed role "may make those responsible for prison conditions more conscious of their responsibilities and may well lead to fewer, rather than more, escapes."

Joining with Judge Wright in the majority opinion was U.S. Circuit Judge Carl McGowan.