An emergency tribunal Saturday convicted and imposed a maximum 30-year sentence on Eugene Hasenfus, the U.S. crewman seized when a Sandinista missile downed his rebel supply plane.

Hasenfus, who had been charged with terrorism and related crimes, appeared to have expected the tribunal's decision. He demonstrated little emotion, just a blink and a sigh, as the verdict was read before a packed courtroom.

Meanwhile, in what appeared to be a sign that authorities may follow the harsh sentence with a gesture of mercy, a top Sandinista leader Saturday referred to Hasenfus as a "father" and a "common citizen" who got in trouble because of the "irresponsible U.S. policy."

Saturday's decision by the People's Anti-Somocista Tribunal found Hasenfus, a 45-year-old resident of Marinette, Wis., guilty of terrorism, violation of Nicaragua's public security laws and conspiracy.

After the verdict was read in Spanish and English, Judge Reynaldo Monterrey leaned across a wooden table in the one-story court near the U.S. Embassy to ask Hasenfus if he wanted to appeal.

"I'd like to consult my lawyer before I appeal, " Hasenfus answered.

"You must say yes or no, " Monterrey answered.

"I'll appeal, " Hasenfus said.

Hasenfus' Nicaraguan defense attorney, Enrique Sotelo Borgen, later said Monterrey had "badgered" his client by demanding an immediate decision. Sotelo, echoing criticisms he has made throughout the trial, called it "another example of the injustice" of the Tribunal. But he said he would prepare a formal appeal.

Hasenfus arrived at the court in the rear cage of a paneled prison truck and was escorted into the courtroom by shoving Interior Ministry guards. He was freshly shaven, dressed in blue jeans and a newly pressed guayabera, with his red hair neatly combed.

Hasenfus' wife Sally and his brother William, a sales manager from Oshkosh, Wis., were waiting in the courtroom. But Hasenfus never appeared to acknowledge their presence.

After the verdict, Hasenfus was shoved again into the truck, handcuffed, and returned to a prison on Managua's outskirts.

Saturday's verdict came 41 days after Sandinista soldiers shot down the U.S.-manned contra supply plane in which Hasenfus had worked as a cargo handler, kicking crated weapons out to rebels waiting on the ground.

The Anti-Somocista Tribunals are two emergency, three- person courts established to try people accused of involvement in the 5-year-old rebel war.

The Tribunals have established an overwhelming tendency to convict. Of 243 verdicts handed down by the lower tribunal this year, none has been an acquittal. The conviction was expected not only because of the evidence, but because of this track record.

Hasenfus' only legal recourse is to appeal his case to a three-person appellate panel of the same Anti-Somocista Tribunal. In 1984, the People's Tribunals responded to two defense appeals by increasing the original sentences -- one from seven to 15 years, the other from seven to 20 years.

The government based its case on testimony by the soldiers who shot down Hasenfus' plane, as well as other evidence, including the defendant's written and oral statements to the court. In those statements, Hasenfus conceded his involvement in the arms shipment destined for the U.S.-backed anti-Sandinista rebels.

In his defense, Sotelo portrayed Hasenfus as a low level employee in a supply operation he knew little about.