NEW YORK (AP) — A 67-year-old man on Thursday admitted hijacking a plane four decades ago and forcing it to land in Cuba, telling a judge how he threatened to cut a female flight attendant's throat to get access to the cockpit, where another man held a gun to the back of the co-pilot.

U.S. District Judge Alvin K. Hellerstein forced Luis Armando Pena Soltren to reveal the details of the hijacking, highlighting the violence and scary nature of an encounter that otherwise might be lost in the stilted language of formal criminal charges.

Pena Soltren, a U.S. resident, returned to the United States in October. He entered his plea to charges of conspiracy to commit air piracy, interfering with a flight crew and kidnapping in federal court in Manhattan. Sentencing was set for June 29.

Pan American Flight 281, which had 103 passengers and crew, was traveling from New York to Puerto Rico on Nov. 24, 1968.

Pena Soltren, speaking through a Spanish interpreter, at first made it seem that he started the hijacking by holding a knife to the throat of a male flight attendant. A prosecutor later clarified that the flight attendant was a woman.

"Did you put it to the back of the neck or the front of the neck," the judge asked.

"I believe it was the front," Pena Soltren answered.

"So you were threatening to cut his throat?" Hellerstein said.

"That's right sir," Pena Soltren answered. "I told him this was an air jacking and I told him I needed him to open the door to the cabin."

Pena Soltren then explained how he and another hijacker entered the cockpit. He said an accomplice held a gun to the back of the co-pilot as the crew steered the plane to Havana.

An indictment returned in December 1968 charged Pena Soltren and two others with using pistols and large knives to force the pilots to divert the flight.

Two of the men were arrested in the mid-1970s and pleaded guilty to their roles in the skyjacking. Another man who was not on the flight was indicted but was found not guilty on all charges.

At sentencing, Pena Soltren could face life in prison, though a letter from prosecutors estimated that his federal sentencing guideline range was roughly between 22 years and 30 years.

Pena Soltren's lawyer, James Neuman, told Hellerstein he expects to ask for a sentence below the guideline range.

Pena Soltren, who has a wife and four grown children, remains held without bail.