BARCELONA, Spain (AP) _ The attorney for an American convicted of drug trafficking filed an appeal Monday of his six-year sentence.

A three-judge provincial court found Conan Owen, 23, of Annandale, Va., guilty of drug trafficking on April 5 and sentenced him to six years in prison.

Owen's lawyer, Ana Campa, said she had filed an appeal. She said the prosecution had meanwhile appealed the court's decision to aquit her client on a separate charge of possession of contraband.

That charge would carry an additional three years in prison.

Ms. Campa said it was normal in Spanish drug cases for the prosecution to appeal if the court failed to convict on the contraband charge.

Owen is a 1986 Syracuse University graduate, a 1984 summer intern in Vice President George Bush's office and a second lieutenant in the U.S. Army reserve.

He went on trial in Barcelona on March 26 after serving more than a year of pretrial detention in the city's 85-year-old prison.

Owen was arrested March 13, 1987 at Barcelona's airport after a customs agent found about four pounds of cocaine in a suitcase he had checked through on his flight from Santiago, Chile, via Amsterdam to Barcelona.

Owen told the court he believed he was taking a suitcase full of tourist brochures to Barcelona for a travel agency that hired him for a four-day free- lance photo assignment. He had been given the suitcase by George Barahona of Alexandria, Va., he said.

Attorney General Edwin Meese III personally delivered copies to Spanish judicial authorities of a statement by Barahona saying Owen knew nothing about the drugs and had been used as a courier.

Under a 1987 Spanish-American treaty. U.S. citizens convicted of crimes in Spain can serve their prison terms in the United States.

But a transfer cannot be approved until all appeals have been exhausted.

he court said it was convinced Owen knew there was cocaine in the suitcase. But it said the cocaine had not passed out of the airport customs area and so it rejected the contraband charge.