Marine Lt. Col. Oliver L. North was trying to avoid being jailed for contempt of court last month when he appealed a sealed ruling by a federal judge on a grand jury subpoena, court records indicate.

A docket entry in North's appeal of the ruling May 8 by U.S. District Court Judge Aubrey Robinson Jr. states that his attorneys filed a motion that day "for stay, or in the alternative, for bail."

The reference to bail in the case docket, on file in the U.S. Circuit Court of Appeals here, indicates that the former National Security Council aide was seeking to block incarceration for contempt of court.

The docket entry was changed later in the day to replace the words "for bail" with "for relief."

North, who has not been jailed, apparently won a stay of a contempt order by the district court, pending his appeal.

North and his attorneys, Brendan Sullivan and Barry Simon, filed their appeal immediately after they appeared before Robinson May 8 on a sealed grand jury matter.

Such proceedings are held in closed court when a grand jury subpoena is challenged.

Public documents later filed with the appellate court indicate that North is challenging the authority of independent counsel Lawrence E. Walsh to enforce subpoenas issued by a special grand jury as part of his investigation of the Iran-contra affair.

North's challenge to the constitutionality of the independent counsel law, under which Walsh was appointed by a special court, is to be aired by a three-judge panel at a public hearing today.

On the day of North's appeal, an emergency three-judge appellate panel issued two sealed orders in the case. Two other sealed orders were issued, on May 15 and May 21.

The court also ordered that the public proceedings be held on the narrow issue of North's challenge to the constitutionality of the Ethics in Government Act.

North's attorneys contend that Walsh lacks legal authority as a federal prosecutor, arguing that his appointment by a special court rather than the executive branch violates the constitutional separation-of-powers doctrine.

The precise nature of the subpoenas challenged by North is unclear. But, since he would be entitled to invoke the Fifth Amendment against self-incrimination before the grand jury, it is unlikely that Walsh is seeking to compel testimony. Rather, it is considered likely that the subpoena or subpoenas seek production of personal papers or documents not protected by Fifth Amendment privilege.

{Meanwhile, Walsh is scheduled to meet today with congressional leaders to renew his request that their Iran-contra investigating panels not grant North limited immunity from prosecution in exchange for his testimony. The committees can vote on immunity as early as Thursday.}